Preliminary Feasibility Study for the South Arturo Mine ...

Effective Date:

December 1, 2020

Report Date:

January 25, 2021

Preliminary Feasibility Study for the South Arturo Mine,

Elko County, NV

Prepared By:

Practical Mining LLC.

495 Idaho Street, Suite 205

Elko, Nevada 89801

Prepared for:

Premier Gold Mines Ltd.

1100 Russell Street, Suite 200

Thunder Bay, Ontario P7B 5N2

Dagny Odell, P.E.

Laura Symmes, SME,

Robert Raponi, P. Eng

Authors:

Page ii

Preliminary Feasibility Study for the South Arturo

Mine, Elko County, NV i-80 Gold Corp..

Practical Mining LLC January 25, 2021

This page intentionally left blank.

i-80 Gold Corp. Preliminary Feasibility Study for the South Arturo

Mine, Elko County, NV

Page iii


Date and Signature Page

The undersigned prepared this Technical Report (TR) report, titled: Preliminary Feasibility Study

for the South Arturo Mine, Elko County, NV, dated the 25th day of January, 2021, with an effective

date of December 1, 2020, in support of the public disclosure of Mineral Resource and Mineral

Reserve estimates for the Arturo Project. The format and content of the Technical Report have

been prepared in accordance with Form 43-101F1 of National Instrument 43-101 – Standards of

Disclosure for Mineral Projects of the Canadian Securities Administrators.

Dated this January 25, 2021

Signed “Dagny Odell” No. 13708, Nevada

Dagny Odell, P.E SME No. 2402150

Practical Mining LLC (Sealed)


Elko, Nevada 89815, USA

(775) 345-3718

Email: [email protected]

Signed “Laura Symmes” SME No. 4196936

Laura Symmes (Sealed)

Practical Mining LLC


Elko, Nevada 89815, USA

(775) 345-3718


Signed “Robert Raponi”

Tommaso Roberto Raponi, P Eng SME No. 2641200

TR Raponi Consulting Ltd. (Sealed)

15-223 Rebecca Street

Oakville, Ontario, CA L6K 3Y2

416-358-8748


mailto:[email protected]



Page iv




Table of Contents

Date and Signature Page ................................................................................................................ iii

Table of Contents ........................................................................................................................... iv

List of Tables ................................................................................................................................. ix

List of Figures ................................................................................................................................ xi

List of Abbreviations ................................................................................................................... xiii

1. Summary ............................................................................................................................... 14

Introduction .................................................................................................................... 14

Property Description ...................................................................................................... 16

Geology and Mineral Resource ...................................................................................... 16

Mineral Reserves ............................................................................................................ 18

Metallurgical Testing and Processing ............................................................................ 19

Mining, Infrastructure, and Project Schedule................................................................. 19

Economic Analysis ......................................................................................................... 19

Conclusions .................................................................................................................... 20

Recommendations .......................................................................................................... 21

2. Introduction ........................................................................................................................... 22

Terms of Reference and Purpose of this Technical Report ............................................ 22

Qualification of the Authors ........................................................................................... 22

Sources of Information ................................................................................................... 23

Units of Measure ............................................................................................................ 23

Coordinate Datum .......................................................................................................... 23

3. Reliance on Other Experts .................................................................................................... 24

4. Property Description and Location ....................................................................................... 25

Property Description ...................................................................................................... 25

Status of Mineral Titles .................................................................................................. 26

Royalties ................................................................................................................. 28

Environmental Liabilities ............................................................................................... 29

Permits/Licenses............................................................................................................. 29



Page v


5. Accessibility, Climate, Local Resources, Infrastructure, and Physiography ........................ 30

Accessibility ................................................................................................................... 30

Climate ........................................................................................................................... 30

Local Resources ............................................................................................................. 30

Infrastructure .................................................................................................................. 30

Physiography .................................................................................................................. 31

6. History................................................................................................................................... 32

Previous Owners ............................................................................................................ 32

Historic Exploration ....................................................................................................... 32

Historic Mining .............................................................................................................. 33

7. Geologic Setting and Mineralization .................................................................................... 34

Regional Geology ........................................................................................................... 34

Local Geology ................................................................................................................ 36

Mineralization ................................................................................................................ 39

8. Deposit Types ....................................................................................................................... 41

9. Exploration ............................................................................................................................ 42

10. Drilling .................................................................................................................................. 43

Drilling and Sampling Methods ..................................................................................... 44

Recovery Factors ............................................................................................................ 45

11. Sample Preparation, Analysis and Security .......................................................................... 47

Sample Preparation Procedures ........................................................................... 47

Laboratory Analysis Procedures ......................................................................... 47

Security................................................................................................................ 48

Standards and Blanks .......................................................................................... 48

Duplicate Assays ................................................................................................. 51

12. Data Verification ................................................................................................................... 53

13. Mineral Processing and Metallurgical Testing ..................................................................... 55

Historical Metallurgical Test Work................................................................................ 55

2017 Metallurgical Samples ........................................................................................... 55

Column Leach Tests ....................................................................................................... 57

Page vi




CIL Bottle Roll Tests ..................................................................................................... 58

Recovery Estimates ........................................................................................................ 60

Conclusions .................................................................................................................... 61

Recommendations: ......................................................................................................... 61

14. Mineral Resource Estimates ................................................................................................. 62

Introduction .................................................................................................................... 62

Modeling of Lithology and Mineralization .................................................................... 65

Drill Data and Compositing ........................................................................................... 66

Drill Data Set ....................................................................................................... 66

Compositing ........................................................................................................ 67

Density ........................................................................................................................... 67

Statistics and Variography ............................................................................................. 68

Grade Capping................................................................................................................ 70

Block Model ................................................................................................................... 70

Grade Estimation and Resource Classification .............................................................. 72

Mined Depletion and Sterilization ................................................................................. 74

Model Validation............................................................................................................ 74

Model Reconciliation .......................................................................................... 75

Pit Optimization ............................................................................................................. 77

Underground Stope Optimizer ....................................................................................... 78

Mineral Resources .......................................................................................................... 79

15. Mineral Reserve Estimates ................................................................................................... 81

Open Pit .......................................................................................................................... 82

Underground Mineral Reserves ..................................................................................... 83

16. Mining Methods .................................................................................................................... 85

SAJV Past Production .................................................................................................... 85

Open Pit .......................................................................................................................... 85

Material Routing ................................................................................................. 86

Geotechnical ........................................................................................................ 89

Underground................................................................................................................... 92



Page vii


Mine Development .............................................................................................. 92

Mining Methods .................................................................................................. 92

Ground Support ................................................................................................... 93

Cemented Rock Fill ............................................................................................. 93

Ventilation and Secondary Egress....................................................................... 93

Dewatering ..................................................................................................................... 94

Mine Plan ....................................................................................................................... 94

17. Recovery Methods ................................................................................................................ 95

Introduction .................................................................................................................... 95

ROM Heap Leaching ..................................................................................................... 95

Oxide Milling ................................................................................................................. 96

Roaster ............................................................................................................................ 97

Autoclave ....................................................................................................................... 98

18. Infrastructure ....................................................................................................................... 100

Dewatering ................................................................................................................... 100

Electrical Power ........................................................................................................... 100

Water ............................................................................................................................ 100

Underground Mine Facilities ....................................................................................... 100

Surface Mine Facilities................................................................................................. 101

19. Market Studies and Contracts ............................................................................................. 102

Precious Metal Markets ................................................................................................ 102

Contracts....................................................................................................................... 103

20. Environmental Studies, Permitting and Social or Community Impact ............................... 104

Environmental Studies and Issues ................................................................................ 104

Social or Community Impacts ...................................................................................... 104

Permitting ..................................................................................................................... 104

Closure and Reclamation Requirements ...................................................................... 106

21. Capital and Operating Costs ............................................................................................... 108

Capital Costs ................................................................................................................ 108

Operating Costs ............................................................................................................ 108

Page viii




El Niño Underground Mine............................................................................... 109

Cutoff Grade ................................................................................................................. 109

22. Economic Analysis ............................................................................................................. 111

Sensitivity ..................................................................................................................... 115

23. Adjacent Properties ............................................................................................................. 117

24. Other Relevant Data and Information ................................................................................. 118

25. Interpretation and Conclusions ........................................................................................... 119

26. Recommendations ............................................................................................................... 120

Risks and Opportunities ............................................................................................... 120

Work Program .............................................................................................................. 120

27. References ........................................................................................................................... 122

Certification of Authors .............................................................................................................. 123



Page ix


List of Tables

Table 1-1 South Arturo Mineral Resources Exclusive of Mineral Reserves Attributable to i-80

(40% Basis) ................................................................................................................................... 17

Table 1-2 South Arturo Mineral Reserves Attributable to i-80 (40% Basis) ............................... 18

Table 1-3 Financial Statistics Attributable to i-80 ........................................................................ 19

Table 2-1 Qualified Professionals ................................................................................................. 22

Table 2-2 Units of Measure .......................................................................................................... 23

Table 4-1 South Arturo JV Unpatented Mining Claims ............................................................... 27

Table 4-2 Franco Nevada USA Leased Claim Royalties .............................................................. 29

Table 6-1 Historic Dee Mine Gold Production ............................................................................. 33

Table 11-1 Gold Blank and Standard Summary Statistics............................................................ 48

Table 13-1 Number of Additional Metallurgical Tests in 2018 ................................................... 57

Table 13-2 Arturo Phase 1 CIL/Leach Tests for Low Grade and High Grade Samples .............. 58

Table 13-3 Arturo Phase 3 CIL/Leach Tests for Low Grade and High Grade Samples .............. 60

Table 14-1 Geology Codes ........................................................................................................... 65

Table 14-2 Indicator Cutoff Values .............................................................................................. 66

Table 14-3 Drill Hole Summary ................................................................................................... 67

Table 14-4 Density ........................................................................................................................ 67

Table 14-5 Search Ellipsoid Parameters- East Deep Underground Zone ..................................... 68

Table 14-6 Search Ellipsoid Parameters - Open Pit Zones ........................................................... 68

Table 14-7 Gold Composite Statistics .......................................................................................... 69

Table 14-8 Composite Grade Capping ......................................................................................... 70

Table 14-9 Block Model Parameters ............................................................................................ 71

Table 14-10 Block Model Variables ............................................................................................. 71

Table 14-11 Estimation Parameters for the Underground Zone ................................................... 72

Table 14-12 Estimation Parameters for the Open Pit Zones......................................................... 73

Table 14-13 South Arturo Underground Classification Conditions ............................................. 73

Table 14-14 South Arturo Open Pit Classification Conditions .................................................... 73

Table 14-15 Estimate Comparison for Au ID3 versus Nearest Neighbor .................................... 74

Table 14-16 Mine to Model Reconciliation .................................................................................. 75

Table 14-17 Mill to Model Reconciliation ................................................................................... 76

Table 14-18 Resource Pit Shells Incremental Statistics ............................................................... 77

Table 14-19 South Arturo Mineral Resources Attributable to i-80 (Exclusive of Reserves) ....... 79

Table 15-1 Mineral Reserves Attributable to i-80 (40%) ............................................................. 81

Table 16-1 South Arturo Joint Venture Gold Recovered (000's oz.) ............................................ 85

Table 16-2 Equipment Requirements ........................................................................................... 85

Table 16-3 Phase 1 Pit Mining and Processing Schedule ............................................................. 86

Table 16-4 Arturo Material Routing ............................................................................................. 87

Page x




Table 16-5 Recommended Inter-ramp and Overall Slope Designs .............................................. 91

Table 16-6 El Niño Production Schedule ..................................................................................... 94

Table 20-1 Arturo Project Significant Permits ........................................................................... 104

Table 21-1 Project Capital Costs ($M) ....................................................................................... 108

Table 21-2 Unit Operating Costs ................................................................................................ 109

Table 21-3 El Niño Unit Mining Costs ....................................................................................... 109

Table 21-4 Reserve Cutoff Grades by Mine and Process ........................................................... 109

Table 21-5 Resource Cutoff Grades by Mine and Process ......................................................... 110

Table 22-1 Income Statement Attributable to i-80’s 40% Interest ............................................. 112

Table 22-2 Cash Flow Statement Attributable to i-80’s 40% Interest ........................................ 112

Table 22-3 Financial Statistics Attributable to i-80 .................................................................... 113

Table 26-1 Project Risks ............................................................................................................. 120

Table 26-2 Opportunities ............................................................................................................ 120

Table 26-3 South Arturo Work Program .................................................................................... 121



Page xi


List of Figures

Figure 1-1 Project Overview ......................................................................................................... 15

Figure 4-1 Location Map .............................................................................................................. 26

Figure 4-2 South Arturo Joint Venture Property .......................................................................... 28

Figure 7-1 Carlin Trend Geology ................................................................................................. 35

Figure 7-2 South Arturo Geology ................................................................................................. 38

Figure 10-1 Drill Hole Collar Locations ....................................................................................... 43

Figure 10-2 Drill Section at 33500N, Looking North................................................................... 44

Figure 11-1 Blank Assay Results BL-46 ...................................................................................... 50

Figure 11-2 GS-25 Standard Reference Material Results ............................................................. 50

Figure 11-3 BCH-OX-06 Standard Reference Material Results .................................................. 51

Figure 11-4 821 Prep Duplicates - ALS Method AA23 ............................................................... 52

Figure 11-5 488 Prep Duplicates - ALS Method AuCN AA13 .................................................... 52

Figure 13-1 South Arturo Phase 1 and Phase 3 Pit Metallurgical Drill Hole Locations .............. 56

Figure 14-1 South Arturo Block Model Extents ........................................................................... 64

Figure 14-2 Medium and High Grade Shells with Faults and Lithology at 33500N, looking North

....................................................................................................................................................... 66

Figure 14-3 Underground Zone Variaograms............................................................................... 68

Figure 14-4 Open Pit Variograms ................................................................................................. 69

Figure 14-5 Section View Displaying Block and Drill Grades at 33500N, looking North .......... 75

Figure 14-6 El Niño Mill to Model Reconciliation ...................................................................... 76

Figure 14-7 Pit Optimization Summary ........................................................................................ 77

Figure 14-8 South Arturo Resource Pit Limit............................................................................... 78

Figure 14-9 El Niño Stope Optimizer Results .............................................................................. 79

Figure 15-1 Mineral Reserve Pit ................................................................................................... 83

Figure 15-2 Isometric View of El Niño Underground Mine and Reserve Excavations ............... 84

Figure 16-1 Arturo Ore Control Flow Chart ................................................................................. 88

Figure 16-2 Pit Wall Sectors ......................................................................................................... 90

Figure 16-3 El Niño Plan View Showing Portals and Main Ramp .............................................. 92

Figure 17-1 Proposed Heap Leach Flowsheet .............................................................................. 96

Figure 17-2 NGM Cortez Flowsheet for Oxide Ore Processing ................................................... 97

Figure 17-3 Goldstrike Roaster Simplified Flowsheet ................................................................. 98

Figure 17-4 Goldstrike Pressure Oxidation Simplified CaTS-RIL Flowsheet ............................. 99

Figure 18-1 El Niño Facilities Layout ........................................................................................ 101

Figure 19-1 Historical Monthly Average Gold and Silver Prices and 36 Month Trailing Average

..................................................................................................................................................... 102

Figure 20-1 Permitted Disturbance ............................................................................................. 107

Figure 22-1 Gold Production and Unit Costs ............................................................................. 111

Page xii




Figure 22-2 Cash Flow Waterfall Chart...................................................................................... 114

Figure 22-3 Gold Price Sensitivity ............................................................................................. 115

Figure 22-4 Operating Cost Sensitivity ...................................................................................... 116

Figure 22-5 Capital Cost Sensitivity ........................................................................................... 116



Page xiii


List of Abbreviations

A Ampere kCFM thousand cubic feet per minute

AA atomic absorption assay Kg Kilograms

A/m2 amperes per square meter km kilometer

AGP Acid Generation Potential km2 square kilometer

Ag Silver kWh/t kilowatt-hour per ton

ANFO ammonium nitrate fuel oil LoM Life-of-Mine

ANP Acid Neutralization Potential m meter

Au Gold m2 square meter

AuEq gold equivalent m3 cubic meter

btu British Thermal Unit masl meters above sea level

°C degrees Celsius mg/L milligrams/liter

CCD counter-current decantation mm millimeter

CIL carbon-in-leach mm2 square millimeter

CoG Cut off grade mm3 cubic millimeter

cm centimeter MME Mine & Mill Engineering

cm2 square centimeter Moz million troy ounces

cm3 cubic centimeter Mt million tonnes

cfm cubic feet per minute MTW measured true width

ConfC confidence code MW million watts

CRec core recovery m.y. million years

CSS closed-side setting NGO non-governmental organization

CTW calculated true width NI 43-101 Canadian National Instrument 43-101

° degree (degrees) oz Troy Ounce

dia. diameter opt Troy Ounce per short ton

EA Environmental Assesment oz/ton Troy Ounce per short ton

EIS Environmental Impact Statement % percent

EMP Environmental Management Plan PLC Programmable Logic Controller

FA fire assay PLS Pregnant Leach Solution

Ft Foot PMF probable maximum flood

Ft2 Square foot POO Plan of Operations

Ft3 Cubic foot ppb parts per billion

g Gram ppm parts per million

g/L gram per liter QAQC Quality Assurance/Quality Control

g-mol gram-mole RC reverse circulation drilling

g/t grams per metric tonne ROM Run-of-Mine

ha hectares RQD Rock Quality Description

HDPE Height Density Polyethylene SEC U.S. Securities & Exchange Commission

HTW horizontal true width Sec second

ICP induced couple plasma SG specific gravity

ID2 inverse-distance squared SPT Standard penetration test

ID3 inverse-distance cubed ton US Short Ton

ILS Intermediate Leach Solution tonne Metric Tonne

LOI Loss On Ignition tpd US Short Tons per day

kA kiloamperes

Preliminary Feasibility Study for the South

Arturo Mine, Elko County, NV

i-80 Gold Corp.


1. Summary

Introduction

Practical Mining LLC (“Practical” or “PM”) was engaged by Premier Gold Mines USA Inc., a

subsidiary of Premier Gold Mines Limited (collectively “Premier” or “the Company”) to prepare

a Preliminary Feasibility Study (PFS) on the South Arturo Project in Elko and Eureka Counties,

Nevada. This Technical Report (TR) is the initial statement of Mineral Resources and Mineral

Reserves for i-80 Gold Corporation (“i-80”). This TR has been prepared in accordance with

National Instrument 43-101 (NI43-101) of the Canadian Security Administrators and follows the

“CIM Estimation of Mineral Resource and Mineral Reserves Best Practices” guidelines (CIM

2019). Mineral Resources classifications are in accordance with the “CIM Standards on Mineral

Resources and Reserves: Definition and Guidelines” (CIM 2014).

The South Arturo project (the "South Arturo Project") is a joint venture (the "SAJV") in respect

of the South Arturo mine (the "South Arturo Mine") located in Nevada, U.S.A between Nevada

Gold Mines LLC ("NGM"), 60% owner and operator, and Goldcorp Dee LLC ("Goldcorp

Dee"), a wholly owned subsidiary of Premier, 40% owner. NGM is a Delaware Limited Liability

Company that is a joint venture combining the Nevada assets of Newmont Mining Corporation

("Newmont") and Barrick Gold Corporation ("Barrick"). The South Arturo Project includes the

completed east lobe Phase 2 (Button Hill) open pit and the active El Niño underground mine at the

bottom of the Phase 2 pit. The northern and southern lobes of the ultimate pit are the Phase 1 (Dee)

and Phase 3 (Arturo) respectively. Mineral Reserves are limited to refractory mineralization from

the Phase 1 pit and El Niño underground. A small portion of the Mineralization extends north from

the Phase 1 pit onto the Barrick Rossi property (Figure 1-1).

The creation of NGM has resulted in a surplus of mineralization for processing at the refractory

facilities. The Goldstrike Roaster Facility is prioritizing high grade underground mineralization

from all NGM underground mines and therefore mining of the South Arturo Phase 1 pit can been

delayed until 2025.

i-80 Gold Corp Summary


Figure 1-1 Project Overview

This TR dated the 25th day of January, 2021 with an effective date of December 1, 2020 is the

initial statement of Mineral Reserves and Mineral Resources for i-80 Gold Corp.’s 40% interest in

the South Arturo Joint Venture.

Cautionary Notes:

1. The financial analysis contains certain information that may constitute "forward-looking information"

under applicable Canadian securities legislation. Forward-looking information includes, but is not

limited to, statements regarding the Company’s achievement of the full-year projections for ounce

production, production costs, AISC costs per ounce, cash cost per ounce and realized gold/silver price

per ounce, the Company’s ability to meet annual operations estimates, and statements about strategic

plans, including future operations, future work programs, capital expenditures, discovery and

production of minerals, price of gold and currency exchange rates, timing of geological reports and

corporate and technical objectives. Forward-looking information is necessarily based upon a number

of assumptions that, while considered reasonable, are subject to known and unknown risks,

uncertainties, and other factors which may cause the actual results and future events to differ

materially from those expressed or implied by such forward looking information, including the risks

inherent to the mining industry, adverse economic and market developments and the risks identified

in Premier's annual information form under the heading "Risk Factors". There can be no assurance



i-80 Gold Corp.


that such information will prove to be accurate, as actual results and future events could differ

materially from those anticipated in such information. Accordingly, readers should not place undue

reliance on forward-looking information. All forward-looking information contained in this

Presentation is given as of the date hereof and is based upon the opinions and estimates of

management and information available to management as at the date hereof. Premier disclaims any

intention or obligation to update or revise any forward-looking information, whether as a result of

new information, future events or otherwise, except as required by law;

Property Description

The South Arturo Project is comprised of unpatented mining claims owned by Goldcorp Dee LLC

(Dee), a wholly owned subsidiary of Premier, and unpatented mining claims leased from Franco-

Nevada Corp. The property encompasses 4,909 acres including the previously mined Dee Pit. The

project is at the northern extent of the Carlin Trend and is approximately four miles from NGM’s

Goldstrike operation.

Geology and Mineral Resource

The South Arturo deposits are sedimentary rock and intrusive hosted gold and silver deposits

hosted mainly in silicified breccias. Oxide gold mineralization in the existing Dee pit mine area is

structurally controlled, dominantly paralleling the north-south striking Dee Fault Zone. Gold was

emplaced by several pulses of silica alteration, which converted mineralized wall rocks into

massive silica or silica breccia. Enriched zones are found where the Dee Fault Zone intersects

northwest trending faults. Minor gold mineralization can be traced along northwest, northeast and

east-west structures trending away from the Dee Fault Zone.

Mineral Resources as of December 1, 2020 are presented in Table 1-1. Open pit and stockpile

Mineral Resources include oxide mineralization amenable to CIL milling or heap leaching along

with refractory roaster material. Underground Mineral Resources are entirely refractory roaster

material.



Table 1-1 South Arturo Mineral Resources Exclusive of Mineral Reserves Attributable to i-80 (40% Basis)

Process

Tons

(000’s)

Tonnes

(000’s)

Au

(opt)

Au

(g/t)

Ag

(opt)

Ag

(g/t)

Au ozs

(000’s)

Ag ozs

(000’s)

Measured

Open Pit 5,117 4,642 0.035 1.21 0.220 7.56 180.6 1,128

Stockpile 783 710 0.016 0.55 0.013 0.44 12.4 10

Underground 18 16 0.518 17.77 0.400 13.72 9.1 7

Measured 5,917 5,368 0.034 1.17 0.193 6.63 200.2 1,145

Indicated

Open Pit 16,073 14,581 0.034 1.17 0.176 6.02 548.6 2,824

Stockpile - - - - - - - -

Underground 47 43 0.374 12.83 0.168 5.77 17.5 8

Indicated 16,120 14,624 0.035 1.20 0.176 6.02 566.1 2,832

Measured and Indicated

Open Pit 21,190 19,223 0.034 1.18 0.186 6.39 729.2 3,952

Stockpile 783 710 0.016 0.55 0.013 0.44 12.4 10

Underground 64 58 0.414 14.18 0.232 7.94 26.7 15

Measured and

Indicated

22.037 19,992 0.035 1.20 0.180 6.19 768.3 3,977`

Inferred

Open Pit 11,092 10,063 0.028 0.95 0.160 5.47 307.5 1,770

Stockpile - - - - - - - -

Underground 60 55 0.247 8.46 0.148 5.08 14.9 9

Inferred 11,153 10,117 0.029 0.99 0.159 5.47 322.4 1,779

Notes:

1. Mineral Resources are exclusive of Mineral Reserves;

2. Mineral Recourses are stated as of December 1, 2020;

3. Mineral Resources are estimated using variable cutoff grades that are dependent upon recovery and

processing method;

4. Open Pit Mineral Resources are constrained within a pit shell generated using a gold price of $1,500 per

ounce and a silver price of $15 per ounce;

5. Underground Mineral Resources are constrained by Mine Stope Optimizer shapes generated using a gold

price of $1,500 per ounce and a silver price of $15 per ounce;

6. Modifying mill to model factors for tons and contained metal have not been applied to the open pit

Mineral Resources;

7. Underground Mineral Resources include modifying mill to model reconciliation factors of 1.025 and –

0.901 applied to tons and contained metal respectively;



i-80 Gold Corp.


8. A Mineral Resource is a concentration or occurrence of solid material of economic interest in or on the

Earth’s crust in such form, grade or quality and quantity that there are reasonable prospects for eventual

economic extraction. The location, quantity, grade or quality, continuity and other geological

characteristics of a Mineral Resource are known, estimated or interpreted from specific geological

evidence and knowledge, including sampling;

9. An Inferred Mineral Resource is that part of a Mineral Resource for which quantity and grade or quality

are estimated on the basis of limited geological evidence and sampling. Geological evidence is sufficient

to imply but not verify geological and grade or quality continuity. An Inferred Mineral Resource has a

lower level of confidence than that applying to an Indicated Mineral Resource and must not be converted

to a Mineral Reserve. It is reasonably expected that the majority of Inferred Mineral Resources could be

upgraded to Indicated Mineral Resources with continued exploration; and

10. The reference point for mineral resources is in situ.

Mineral Reserves

Mineral reserves are reported only for the Phase 1 pit and El Niño underground and only for

material amenable to roasting. Mineral Reserves are summarized in Table 1-2.

Table 1-2 South Arturo Mineral Reserves Attributable to i-80 (40% Basis)

Tons

(000’s)

Tonnes

(000’s)

Au

(opt)

Au

g/t

Ag

(opt)

Ag

(g/t)

Au ozs

(000’s)

Ag ozs

(000’s)

Proven

Open Pit 2,617 2,374 0.089 3.05 0.500 17.15 233 1,309

Stockpile 220 200 0.074 2.54 0.129 4.44 16 29

Underground 66 60 0.186 6.38 0.135 4.62 12 9

Proven 2,904 2,634 0.090 3.09 0.464 15.90 261.5 1,347

Probable

Open Pit 1,212 1,100 0.063 2.16 0.419 14.37 76.4 508

Stockpile - - - - - - - -

Underground 72 66 0.175 6.00 0.131 4.50 12.7 10

Probable 1,285 1,166 0.069 2.38 0.403 13.81 89.1 518

Proven and Probable

Open Pit 3,829 3,474 0.081 2.77 0.475 16.27 309.1 1,817

Stockpile 220 200 0.074 2.54 0.129 4.44 16.4 29

Underground 139 126 0.180 6.18 0.133 4.56 25.0 18

Proven and Probable 4,189 3,800 0.084 2.87 0.445 15.23 350.5 1,864

Notes:

1. Mineral Reserves are stated as of December 1, 2020;

2. Mineral Reserves are estimated using variable cutoff grades that are dependent upon recovery and

processing method;

3. Mineral Reserves have been estimated at a gold price of $1,200 per troy ounce and a silver price of $15

per ounce;



4. The base case economic analysis is presented at a gold price of $1,400 per ounce and a silver price of

$15 per ounce;

5. Underground Mineral Reserves include modifying mill to model reconciliation factors of 1.14 and – 0.96

applied to tons and contained metal respectively;

6. Modifying factors for tons and contained metal have not been applied to open pit Mineral Reserves; and,


Metallurgical Testing and Processing

The metallurgical test results determined that sulfide ore and ore containing preg-robbing organic

carbon above the target cut-off gold grade would be roasted and oxide ore above the target cut-off

gold grade would be processed via ROM heap leach. Mill grade oxide ore could be processed via

CIL processing. Mineralized material containing preg-robbing organic carbon below the cut-off

gold grade for roasting will be considered waste. The mill recovery ranges from 48% to 92%

depending on the process employed. Column leach tests on Phase 1 low grade oxide samples

showed poor gold recoveries (average of 31%) while Phase 3 samples had higher recoveries

averaging 62%. Column leach test recoveries are factored to estimate ROM recoveries.

Mining, Infrastructure, and Project Schedule

South Arturo is being mined by both open pit and underground methods. All work is performed

by and supported by NGM’s Goldstrike operation. A qualified contractor has been retained to

complete underground mining. All required infrastructure is in place.

Underground mining is from the bottom of the Phase 2 pit and is currently producing

approximately 600 tpd of roaster material. All mineralization is mined using underhand drift and

fill methods.

Open pit mining is a conventional shovel truck operation using large electric or hydraulic shovels

and 320-ton capacity haul trucks. The open pit mining rate is approximately 135,000 tpd.

Economic Analysis

Table 1-3 Financial Statistics Attributable to i-80

Parameter El Niño UG Phase 1 Pit Combined

Gold price - base case (US$/oz) $1,400 $1,400 $1,400

Silver price - base case (US$/oz) $15 $15 $15

Mine life (years) 2.0 18 18

Mining Rate (tons/day) 600 135,000 N/A

Average grade (oz/t Au) 0.180 0.081 0.084

Average gold recovery (roaster %) 88.5% 80.8% 81.4%

Average annual gold production (koz) 12 15 16

Total recovered gold (koz) 23.5 265.6 289.1



i-80 Gold Corp.



Capital (M$) $- $29.7 $29.7

Cash cost (US$/oz)1 $1,028 $622 $655

All-in sustaining cost (US$/oz)1,3 $1,066 $845 $863

All in Costs (US$/oz)1,4 $1,066 $845 $863

Project after-tax NPV5% (M$) $7.2 $76.4 $83.7

Project after-tax IRR NA 54% NA

Payback Period NA 7.0 5.9

Profitability Index 5%2 NA 4.3 4.6

Notes:

1. Net of byproduct sales;

2. Profitability index (PI), is the ratio of payoff to investment of a proposed project. It is a useful tool for

ranking projects because it allows you to quantify the amount of value created per unit of investment. A

profitability index of 1 indicates breakeven;

3. Excludes, construction capital, exploration, corporate G&A, interest on debt, and corporate taxes; and

4. Excludes exploration, corporate G&A, interest on debt, and corporate taxes; and,






plans, including future operations, future work programs, capital expenditures, discovery and production

of minerals, price of gold and currency exchange rates, timing of geological reports and corporate and

technical objectives. Forward-looking information is necessarily based upon a number of assumptions

that, while considered reasonable, are subject to known and unknown risks, uncertainties, and other

factors which may cause the actual results and future events to differ materially from those expressed or

implied by such forward looking information, including the risks inherent to the mining industry, adverse

economic and market developments and the risks identified in Premier's annual information form under

the heading "Risk Factors". There can be no assurance that such information will prove to be accurate,

as actual results and future events could differ materially from those anticipated in such information.

Accordingly, readers should not place undue reliance on forward-looking information. All forward-

looking information contained in this Presentation is given as of the date hereof and is based upon the

opinions and estimates of management and information available to management as at the date hereof.

Premier disclaims any intention or obligation to update or revise any forward-looking information,

whether as a result of new information, future events or otherwise, except as required by law.

Conclusions

Resource Delineation and Exploration

1. Multiple zones of mineralization are open along strike and down dip from previous

mineralization intercepts;

2. The geology at South Arturo is well understood;

3. Drilling and data management procedures are adequate; and,

4. Mineral resource modelling follows generally acceptable practices.

Processing and Metallurgical Testing



1. The Goldstrike Roaster will not be available for processing South Arturo open pit

refractory mineralization before 2026 and it will take 12 years to complete processing of

South Arturo refractory production from the Phase 1 pit;

2. Previous bottle roll and column leach tests from Phase 1 composites achieved poor

recoveries. These composites may not be representative of shallower oxide mineralization;

3. Phase 3 sample column leach tests gold recoveries averaging 62%; and,

4. Mineral Reserves include only mineralization amenable to roasting.

Mining and Infrastructure

1. The South Arturo open pit will be mined at 135,000 tons per day using facilities and

equipment from NGM’s Goldstrike operations; and,

2. Underground drift and fill mining is successfully extracting mineralization below the Phase

2 Pit.

Financials

1. Financial analysis of the South Arturo Project indicates i-80’s 40% interest has a net

present value at a 5% discount rate of US$83.7M; and,

2. The open pit and underground mines are independent, profitable, stand-alone operations.

Recommendations


1. Drill untested targets on trend with existing mineralization intercepts.

Metallurgical Testing

1. Expedite bottle roll and column leach tests from Phase 1 composites taken from shallower

oxide mineralization.

Mining

1. Develop mineral resources down dip from current El Niño underground workings; and,

2. If positive metallurgical testing results are achieved, accelerate construction of the leach

pad and mining of the Phase 1 pit targeting oxide mineralization.



i-80 Gold Corp.


2. Introduction

Terms of Reference and Purpose of this Technical Report

Premier Gold Mines Ltd, and Premier Gold Mines USA Inc. (collectively “Premier”) has spun off

its Nevada assets in the formation of i-80 Gold Corporation (i-80), a newly created public

company. This TR was prepared in accordance with the requirements of NI 43-101 and Form 43-

101F1 (43-101F1) for technical reports and is the initial statement of Mineral Reserves and

Mineral Resources for i-80 at the South Arturo Project for i-80.

Mineral resource and mineral reserve definitions are set forth in “Canadian Institute of Mining,

Metallurgy and Petroleum (CIM) – Definition Standards for Mineral Resources and Mineral

Reserves adopted by CIM Council on May 10, 2014.”

Qualification of the Authors

This TR includes technical evaluations from three independent consultants. The consultants are

specialists in the fields of geology, exploration, metallurgy, open pit and underground mining.

None of the Qualified Professionals (QPs) has any beneficial interest in Premier or i-80 or any of

its subsidiaries, or in the assets of Premier or i-80 or any of its subsidiaries or in any property near

the South Arturo Mine. Similarly, the QPs do not have any beneficial interest in Barrick Gold

Corp., Newmont Mining Corp. or Nevada Gold Mines LLC or any of their subsidiaries. The QPs

will be paid a fee for this work in accordance with normal professional consulting practices.

The QP’s and the sections of this report each contributed to are listed in Table 2-1. QP’s Odell and

Symmes personally inspected the El Niño underground, underground infrastructure, and Arturo

open pits. They also interviewed NGM personnel responsible for exploration, geology, resource

modelling, database management, cost accounting and mine engineering. QP Raponi resides in

Canada and international travel restrictions related to the Covid-19 pandemic prevented him from

making a personal inspection of the project. However, QP Raponi conducted a remote interview

with the NGM metallurgist responsible for Arturo. The Certificates of Qualifications for each are

provided in at the end of this report.

Table 2-1 Qualified Professionals

Company

QP Title Discipline

Most Recent

Personal Inspection Responsible Sections


Dagny Odell Manager Mining, Mineral

Resources and

Mineral Reserves

June 25, 2020

1.1 – 1.4, 1.6 - 1.9, 2 – 6, 11,

14 – 16, 18 - 26

i-80 Gold Corp Introduction


Company

QP Title Discipline

Most Recent

Personal Inspection Responsible Sections

Laura Symmes Sr. Geologist Geology and

Mineral Resources

June 25, 2020 7 - 10, 12, 14

Raponi Engineering

T. Raponi President Metallurgy None 1.5, 1.8, 1.9, 13, 17, 25, 26

Sources of Information

Information sources are documented either within the text and cited in references or are cited in

references only. The authors believe the information provided by Premier and NGM to be accurate

based on their work at the project. NGM provided the resource block model and mining plans.

Geotechnical pit wall design was prepared by Piteau and Associates, the Joint Venture’s

geotechnical consultant (Piteau 2010).

Units of Measure

U.S. Imperial units of measure are used throughout this document unless otherwise noted.

US/Metric conversion factors are listed in Table 2-2. Currency is expressed as United States

Dollars unless otherwise noted.

Table 2-2 Units of Measure

US Imperial to Metric Conversions

Linear Measure Weight

1 inch = 2.54 cm 1 short ton = 2,000 lbs = 0.9071 metric tons

1 foot = 0.3048 m 1 lb = 0.454 kg = 14.5833 troy oz.

1 mile = 1.6 km Assay values

Area Measure 1 ounce per short ton = 34.2857 g/t

1 acre = 0.4047 ha 1 part per million = 0.0292 opt

1 square mile = 640 acres = 259 ha 1 troy oz. = 31.10348 g

Coordinate Datum

Spatial data utilized in analysis presented in this TR are projected in the NGM local mine grid.



i-80 Gold Corp.


3. Reliance on Other Experts

Mining claim and land holding status is reliant on information provided by Erwin Thompson and

Faillers, Premier legal counsel. Permitting and environmental status was provided by Premier and

NGM.

i-80 Gold Corp Property Description and Location


4. Property Description and Location

Property Description

The South Arturo Joint Venture (SAJV) is located 34 miles north west of Carlin, Nevada at 21°27’

N and 116°26’ W. (Figure 4-1). Parties to the Joint Venture are Nevada Gold Mines LLC (NGM),

a Delaware Limited Liability Company, 60% interest and operator and Goldcorp Dee LLC (GD)

a Nevada Limited Liability Company, 40% interest. Goldcorp Dee LLC is a wholly owned

subsidiary of i-80 Gold Corporation (i-80).

The Project encompasses 4,909 acres of federal land administered by the Bureau of Land

Management.



i-80 Gold Corp.


Figure 4-1 Location Map

(BLM 2012)

Status of Mineral Titles

The Project comprises 217 unpatented mining claims leased from Franco-Nevada U.S.

Corporation (Franco) and 171 unpatented mining claims owned by Goldcorp Dee LLC (Dee). A



summary of leased and owned claims is provided in Table 4-1. Nevada Gold Mines LLC (NGM)

holds a 60% interest and is the operator of the SAJV. Dee holds the remaining 40%.

Table 4-1 South Arturo JV Unpatented Mining Claims

Claim Group Claim Type County Owner of Record Number

ANT Lode Elko/Eureka Goldcorp Dee LLC 20

B.E. Lode Elko Franco-Nevada USA 2

Bart Lode Elko Franco-Nevada USA 45

BC Lode Elko/Eureka Goldcorp Dee LLC 40

BS Lode Elko Franco-Nevada USA 13

DEE Millsite Elko Goldcorp Dee LLC 102

JAG Lode Elko Franco-Nevada USA 62

KCH Lode Elko/Eureka Goldcorp Dee LLC 4

LUKE Lode Elko Goldcorp Dee LLC 5

PAG Lode Elko Franco-Nevada USA 4

RUSS Lode Elko Franco-Nevada USA 90

RUSS Fraction Lode Elko Franco-Nevada USA 1

(Erwin, et al 2020)

On June 2, 2015 Premier completed the acquisition of 100% interest in Goldcorp Dee LLC

(“Dee”), a Nevada Limited Liability Company, from Goldcorp Inc., an Ontario Corporation and

Goldcorp USA, a Nevada Corporation (collectively “Goldcorp”). Sale terms included base cash

consideration of $20,000,000, reasonable development and construction costs of $15,690,917, and

cash contributions of $986,648.40 made by Goldcorp to the South Arturo Joint Venture (“SAJV”).

Non-cash consideration included the transfer of 5% of Premier’s interest in the Rahill-Bonanza

Joint venture in Ontario, Canada to Goldcorp. Premier also granted Goldcorp the Right of First

Refusal (“Cove ROFR”) on any proposed third-party joint ventures or third-party sales of

Premier’s 100% owned McCoy-Cove Project in Lander County, Nevada. Within 30 days of

closing Goldcorp contributed C$12,500,000 in exchange for securities of Premier in a financing

to be completed by Premier (Goldcorp et al., 2015).

On December 16, 2020 Premier Gold Mines announced that it has entered into an agreement with

Equinox Gold whereby Equinox Gold would acquire all the outstanding shares of Premier. At

closing, Premier will spin-out its 40% interest in the SAJV to i-80 Gold Corporation (i-80).



i-80 Gold Corp.


Figure 4-2 South Arturo Joint Venture Property

Royalties

Royalties on the Franco leased claims vary from 4% to 8% depending on gold grade and process

type. Details of the royalty schedule are shown in Table 4-2.



Table 4-2 Franco Nevada USA Leased Claim Royalties

Gold Assay 0 < 𝐴𝑢 𝑜𝑝𝑡 ≤ 0.13 0.13 < 𝐴𝑢 𝑜𝑝𝑡 ≤ 0.26 0.26 < 𝐴𝑢 𝑜𝑝𝑡

Oxide 4% 6% 8%

Refractory 6% 6% 6%

Environmental Liabilities

At completion of operations the SAJV is required to reclaim the project site as specified in the

Nevada Division of Environmental Quality Bureau of Mining Regulation and Reclamation

(BMRR) approved reclamation plan. Closure requirements include reclamation of waste rock

storage facilities, heap leach pad, roads, removal of all facilities, revegetation and monitoring of

vegetation regrowth and water quality. The SAJV has in place a $32,512,581 reclamation bond

with the state of Nevada (NDEPBMRR 2020).

Pit lakes are anticipated to begin forming 100 years from the end of NGM’s dewatering program

at the Goldstrike operation and reach an elevation of 5093 feet amsl 250 years later. The South

Arturo Pit lake is modeled to act as a groundwater sink with a pH of 7 – 7.8 and total dissolved

solids ranging from 1,400 to 1,500 mg/l (BLM 2014).

Permits/Licenses

The SAJV has multiple active permits from the Bureau of Land Management and State of Nevada,

Bureau of Alcohol, Tobacco and Firearms (BATF) for the storage and use of explosives and

numerous minor permits and licenses with county, state and federal agencies. Significant permits

are discussed in Section 20.



i-80 Gold Corp.


5. Accessibility, Climate, Local Resources, Infrastructure, and

Physiography

Accessibility

Access to the Project area is via State Highway 766 north 18.9 miles from the town of Carlin, and

then 14.5 miles north west on Nevada Gold Mines access road. Alternatively, west on i-80 for 26.3

miles to Dunphy exit 254, then north on the T-S / Boulder Valley Road for 26.9 miles to the project

site.

Climate

The climate in Elko and Eureka Counties is typical of the high-desert environment. Average July

temperatures range between 65°F and 75°F in the lower valleys and cooler in the higher elevations.

Summer highs in the valleys are approximately the mid-90°F, with temperatures in the range of

50°F or 60°F at night. Winter temperatures average between 20°F and 30°F in the valleys with

the possibility of frost from early September through June.

Average rainfall is 10 in to 15 in, with less than 10 in of rain in the lowest areas and up to 20 in

occurring in the mountains. The majority of precipitation falls between November and May, with

the possibility of summer thunderstorms.

Mining operations operate year-round with infrequent weather delays.

Local Resources

The Carlin Trend has a long history of mining activity, and mining suppliers and contractors are

locally available. Both experienced and general labor is readily available from the towns of Elko,

Carlin and Spring Creek in Elko County and Battle Mountain in Lander County.

Infrastructure

Site facilities and infrastructure include:

• Access roads;

• Waste rock disposal facilities;

• Electrical substation supplied from the NV energy grid;

• Electrical distribution lines;

• Explosives storage;

• 1 MM gallon water storage tank;

• Underground backfill plant, shop, offices and staging area;

i-80 Gold Corp Accessibility, Climate, Local Resources, Infrastructure,

and Physiography


• Storm water control structures; and

• Perimeter fencing.

Physiography

The Project lies in the Basin and Range Province, a structural and physiographic province

comprised of generally north to north-northeast trending, fault bounded mountain ranges separated

by alluvial filled valleys. The Mine is situated within an area of low, broad, northwest-southeast

trending ridges. The elevations in the area range from 5,300 to 6,200 feet amsl. Within the Mine

area, there are several ephemeral stream drainages. Common vegetation found in the area includes

cheat grass, foxtail chess, mustard grass, shadscale, green rabbitbrush, sagebrush, western

wheatgrass, and sedge.



i-80 Gold Corp.


6. History

Previous Owners

Mining activities at Dee were initiated by Rayrock Mines Ltd. (Rayrock) and its subsidiary Dee

Gold Mining Co. (Dee Gold) in 1994.

The Barrick Dee Mining Venture (BDMV) was formed in 1997 through an exploration agreement

between Barrick Gold Exploration Inc. and Dee Gold to explore areas outside of the active mining

area. Barrick was the operator and 60% owner of BDMV and Dee Gold held 40%. Rayrock was

acquired by Glamis in 1999. In 2007 Glamis was acquired by Marigold Mining Company

(Marigold), a wholly owned subsidiary of Goldcorp. Premier acquired Goldcorp’s 40% interest in

BDMV on June 2, 2015.

Drilling by Barrick in July 2005 led to the discovery of the South Arturo deposit beneath the Dee

Gold waste rock facilities.

Historic Exploration

Exploration of the Carlin Trend has been ongoing since the early 1900’s. Exploration for barite

and gold began on the property in 1975. Between 1981 – 1983 the property was explored by

Cordex Exploration Company and two gold deposits were identified. Subsequent exploration work

on the property has been performed by FMC Gold/Meridian, Dee Gold, Glamis and Barrick.

The majority of the South Arturo deposit lies on the BDMV property with a minor portion

extending north onto the Rossi property.

Exploration work conducted by Barrick includes:

• Re-evaluation and assembling pertinent data from both properties into a combined data set;

• Property wide detailed geologic mapping at a scale of 1:2400;

• Geologic mapping of the Dee open pit at a scale of 1:1200;

• Geologic mapping at 1:600 and sampling of approximately 12,000 m of trenches;

• Geologic mapping at 1:1200 and sampling the Queen and Sagehen Barite open pits;

• Geologic mapping of the Dee and Storm underground workings at 1:240;

• Acquisition and evaluation of 210-line km of magnetotelluric and Induced Polarization

(MT/IP) data (property wide survey) on lines spaced 300 m apart;

• Acquisition and evaluation of 140-line km of ground magnetics;

• Acquisition and evaluation of 27-line km of Controlled Source Audio-frequency

Magnetotelluric (CSAMT) data, a frequency-based electromagnetic sounding geophysical

survey technique that uses a remote synchronous signal source;

i-80 Gold Corp History


• Collection of 1,035 gravity stations on a 150 m x 150 m survey;

• Collection and analysis of more than 2,500 soil samples on various grid spacings;

• Completion of a 3D Vulcan/Geocad property wide geologic model;

• Reprocessing and detailed Geophysical analysis of property wide geophysical data;

• Detailed geochemical analysis of property wide geochemical data; and

• More than 338,473 m of combined RC, mud rotary, sonic, and core drilling.

Historic Mining

Production from the Dee open pit initiated in 1984 and the Dee Deep North underground mine

began producing in 1999. Both operations ceased in December 2000 due to low gold prices. Gold

production during this period is detailed in Table 6-1.

Table 6-1 Historic Dee Mine Gold Production

Year Mill (oz) Heap Leach (oz) Total (oz)

1984 6,388 - 6,388

1985 42,613 7,019 49,632

1986 43,351 7,682 51,033

1987 43,657 9,377 53,034

1988 43,698 6,090 49,788

1989 35,193 10,467 45,660

1990 37,035 11,029 48,064

1991 37,058 4,988 42,046

1992 29,900 8,918 38,818

1993 6,568 19,204 25,772

1994 9,083 16,541 25,634

1995 28,829 14,954 43,782

1996 28,829 9,789 38,618

1997 33,977 5,655 39,632

1998 25,070 3,453 28,523

1999 17,224 841 18,065

Total 468,482 136,006 604.488

Reclamation and closure activity began in 2000 on the historic Dee leach pads, tailings

impoundment and waste rock disposal areas. All surface facilities except electrical supply and

water supply system were removed. NGM began resloping off the Phase 2 East Waste Rock

Storage Facility in 2019.



i-80 Gold Corp.


7. Geologic Setting and Mineralization

Regional Geology

The South Arturo Mine is located within the northern Carlin Trend in the Basin and Range

physiographic province in northeastern Nevada. Late Devonian-Mississippian continental arc

collision (Antler Orogeny) juxtaposed a siliceous deep-water assemblage over the favorable shelf

and slope facies carbonate assemblage. A sequence of compressional and extensional tectonic

events has transformed the district into large scale, north-northwest trending folds, and northwest

to northeast trending faults, which exposed “windows” of the lower plate rocks within the upper

plate. The northern Carlin Trend is defined by a north-northwest trending alignment of gold

deposits in a series of these windows. The windows in the Carlin Trend from south to north are

the Railroad, Rain, Maggie Creek, Carlin, Lynn, and Bootstrap. The South Arturo Mine is located

within the Bootstrap Window (Figure 7-1).

Igneous activity along the Carlin Trend has occurred periodically from the Jurassic through the

Tertiary with the emplacement of medium size diorite stocks, diorite, dacite, and lamprophyre

dikes and sills, and a very large deep-seated intrusion at Mary’s Mountain. A two-mile-wide

northwest trending lamprophyre dike swarm defines the overall axis of the Carlin Trend.

i-80 Gold Corp Geologic Setting and Mineralization


Figure 7-1 Carlin Trend Geology



i-80 Gold Corp.


Local Geology

In general, the South Arturo deposits are sedimentary rock and intrusive hosted gold and silver

deposits hosted mainly in silicified breccias. Oxide gold mineralization in the existing Dee pit

mine area is structurally controlled, dominantly paralleling the north-south striking Dee Fault

Zone. Gold was emplaced simultaneous to several pulses of silica alteration, which converted

mineralized wall rocks into massive silica or silica breccia. Enriched zones are found where the

Dee Fault Zone intersects northwest trending faults. Minor gold mineralization can be traced along

northwest, northeast and east-west structures trending away from the Dee Fault Zone.

The oldest formation known near the South Arturo Mine is the Ordovician Hanson Creek dolomite,

intersected in a deep drill hole west of the deposit. A 700-foot-thick section of the Silurian-

Devonian Roberts Mountains limestone occurs above the Hanson Creek dolomite. There is a

gradational contact between the Roberts Mountains formation and the overlying Silurian-

Devonian Bootstrap limestone. The Bootstrap limestone is a grey, massive limestone deposited in

a reef margin environment. The thickness of the Bootstrap limestone ranges from less than 200

feet to more than 400 feet along a north-northwest trend. West of the reef margin is a full section

of Devonian Popovich Formation slope-facies carbonates. East of the reef margin, the Popovich

carbonates thin to less than 100 feet above the Bootstrap limestone. The upper contact of the

Popovich Formation grades conformably into the Devonian Rodeo Creek siliceous argillite and

mudstone sequence, which ranges in thickness from 200 feet to 2,500 feet north of the Mine. The

stratigraphic section west of the Mine is consistent with the type section described by Newmont

Mining Corporation (Newmont) at Bootstrap/Capstone/Tara and with the Popovich section

described by Barrick at Rodeo/Goldstrike. The stratigraphic section east of the Mine is consistent

with the type section described by Barrick at Meikle (Barrick, 2009).

Upper plate rocks at the South Arturo Mine consist of a sequence of mudstone, argillite, and

bedded cherts of the Vinini, Elder, and Slaven Chert formations. The Tertiary Carlin Formation, a

sequence of tuffaceous sedimentary rocks and air-fall tuff, fills channels and depressions in the

Dee Mine area.

At least three generations of dikes occur at South Arturo. The most notable zone is a 1.5 mile wide

northwest trending lamprophyre dike swarm that includes the Jurassic Arturo dike. Other, possibly

Tertiary, intrusive rocks include a quartz-bearing biotite dacite dike in the Dee fault and an andesite

dike along the northeast Flower structure.

North-south striking Basin and Range faulting is prominent throughout the deposit. The Dee Fault

Zone controls mineralization in the Dee area (Phase 1). Northeast and northwest striking faults act

as secondary controls on mineralization. The Hinge fault controls mineralization in the Hinge



zone; West Button Hill mineralization is coincident with mapped structures encountered in the

Phase 2 mining (Figure 7-2).



i-80 Gold Corp.


Figure 7-2 South Arturo Geology



Mineralization

The South Arturo gold-silver deposits can be divided into five mineralized areas. These areas are

the South Arturo, West Button Hill, Southwest Dee pit, Deep North, and Hinge. The majority of

these deposits are classified as “Meikle Type” breccia hosted Carlin type deposits. A complex set

of breccias occur at the upper contact of the Bootstrap limestone. These breccias can be generalized

into four basic types: silicified heterolithic breccias, silica-Sulfide breccia, dolomite breccia, and

cavity-fill breccias.

While mineralization is widespread throughout the South Arturo Mine area, localized high-grade

gold mineralization drives the economics and mine locations.

South Arturo

The northern extent of South Arturo mineralization lies approximately 200 feet southeast of the

Dee pit and under 600 feet of waste rock. An overall north-south orientation to mineralization is

inferred from the grade thickness contours, which define an area 1,700 feet in a north-south

direction by 300 feet to 350 feet wide in an east-west direction. The mineralization and Tertiary

contact dip 15° to 20° to the south. Drilling has shown that rocks are oxidized to a depth of up to

2,000 feet. Paleozoic rocks host the mineralization mainly in multi-stage, multi-lithic breccias with

gold values ranging from 0.006 opt Au. These breccias are commonly formed by karsting or

dissolution of carbonate rock and subsequent collapse and cavity fill. In general, decalcification is

followed by weak to strong silicification with local argillization. Silver to gold ratios are generally

1:1 at grades of greater than 0.06 opt Au but increase to 5:1 at lower gold grade values.

Dee Deep North

Dee Deep North is a north-northeast trending pod of mineralization that plunges slightly north and

is approximately 600 feet long, 150 feet wide, and 150 feet thick. The majority of high-grade

refractory mineralization is in silica-Sulfide breccia within a flat to west-dipping silicified, multi-

lithic breccia body above the Bootstrap limestone between 4,900 FASL and 5,100 FASL. The

principal controls are the north-northeast trending high angle EB fault and southwest dipping low

angle structures.

Southwest Dee

The Southwest Dee pit mineralization is along the north-northeast trending, west dipping Dee Fault

Zone. The mineralization is carbonaceous, partially oxidized, variably silicified mudstone/

siltstone breccia approximately 300 feet in a north-south strike length, 100 feet wide, and 150 feet

in thickness. The mineralization sits between 4,900 FASL and 5,100 FASL, with a small portion

exposed along the southwest high wall at the bottom of the Dee pit.



i-80 Gold Corp.


West Button Hill

The West Button Hill mineralization trends north-northeast for over 2,000 feet in strike length, in

pods that vary up to 600 feet wide and 50 feet thick. The majority of high-grade refractory

mineralization is in the lower Rodeo Creek Formation and multi-lithic breccias above the

Bootstrap limestone. The principal controls are the north-northeast and north-south trending high

angle structures and favorable host rocks. The mineralization has been shown to extend 1,230 feet

below pre-mining surface elevation, as it is offset on the northeast striking, down-to-the-east Tara

West fault.

Hinge

The Hinge zone is a north-south striking zone that lies between the Arturo zone to the south west

and West Button Hill to the northeast and is due east relative to the existing Dee pit. It is

approximately 1,400 feet long and up to approximately 300 feet wide, lying between elevations of

4,750 FASL and 5,250 FASL at depths from 330 feet to 900 feet below surface. Mineralization is

hosted in the lower portion of the Rodeo Creek Formation and silicified breccias of the Basal

Rodeo Creek and Popovich Upper Mud units. Breccia bodies drape the Bootstrap limestone.

Mineralization in the Hinge zone is controlled by the Hinge fault, a steeply east dipping north-

south structure that appears to be a northerly extension of faults in Newmont’s Bootstrap pit to the

south. Intersecting faults that influence mineralization have not been clearly identified. Much of

the mineralization is partially to completely oxidized, even in the more deeply buried zones.

i-80 Gold Corp Deposit Types


8. Deposit Types

The South Arturo Mine is located in the northern end of the Carlin Trend, a 40 mile long north-

northwest alignment of sedimentary rock-hosted gold deposits. These deposits are generally

known as Carlin-type deposits named after the Carlin deposit. More than 50 million ounces of gold

have been mined from the Carlin Trend since 1980. Characteristically, the gold mineralization in

the Carlin-type gold deposits is dispersed, micron-sized, and found commonly on the rims of pyrite

grains in predominately carbonate-bearing host rocks. Decalcification, silicification, and

dolomitization are the most dominant alteration features. Generally, there is negligible base metal

content, low silver to gold ratios, and a geochemical enrichment in arsenic, antimony and mercury.

Carlin-type gold deposits represent a spectrum of deposit types including the classic stratigraphic

hosted deposit end member, collapse breccia hosted deposit end member, and structurally

controlled deposit end member. Most, if not all, of these deposit types contain individual

components of the end members. Most of the South Arturo gold mineralization is considered to be

of the breccia hosted Carlin-type with structural controls, similar to Barrick’s Meikle deposit

located approximately 4 miles to the southeast.



i-80 Gold Corp.


9. Exploration

Premier has not conducted exploration at South Arturo. Exploration conducted by Nevada Gold

Mines and previous operators is summarized in Section 6 History and Section 10 Drilling.

i-80 Gold Corp Drilling


10. Drilling

Drilling has been carried out over the 50-year history of the Carlin complex by several operators

including Nevada Gold Mines, Barrick, Glamis (Dee Gold), Haliburton and Meridian. Premier has

not drilled holes on the property. A number of drilling techniques have been used, including

reverse circulation (RC), core, conventional air rotary, and conventional air mud. Currently, only

RC above the water table and core drilling are used. Figure 10-1 shows the location of holes drilled

in the South Arturo area, which total more than 3,280 holes.

Figure 10-1 Drill Hole Collar Locations



i-80 Gold Corp.


Drilling and Sampling Methods

Drill holes are planned to intersect mineralization as near to perpendicular as available drill

platforms allow. The style of mineralization at South Arturo is well understood, which allows for

reasonable interpretation of mineralized intervals in conjunction with close drill spacing. Figure

10-2 shows a representative drill section at 33500 N.

Figure 10-2 Drill Section at 33500N, Looking North

Drilling is carried out by contract drill companies and supervised by Nevada Gold Mines

personnel. Core drilling typically uses HQ and NQ diameter core. PQ core is used for obtaining

samples for metallurgical testing. Core is placed in labelled cardboard boxes. Drillers mark each

drill run by placing a wooden block in the core box. Length of the run and length of sample

recovered are recorded on each block by the driller. Core boxes are transported to the Goldstrike

core shed by Nevada Gold Mines personnel; geologists and geotechnicians then photograph, log,

and sample the core.

Geologists log data digitally using a standardized set of descriptive options. Data cells are filled

by selecting from drop-down lists to complete several data fields including rock quality description

(RQD), structure, lithology, alteration, and mineralization. Sample intervals are chosen by the

geologist to best characterize mineralization. Core sample lengths are nominally five feet, ranging

from two feet to seven feet. Sampling is completed by geotechnicians. Depending on the purpose

of the drill hole the entire core may be placed in the sample bag or the core may be cut

longitudinally with a water-cooled diamond blade saw. If the core is cut, the remaining half is

returned to the original core box and stored on-property. When the core is too fragmented to be

i-80 Gold Corp Drilling


cut with a saw, the sampler scoops the sample from the core box, taking half longitudinally as best

they can. The sampler inserts QAQC samples in the sample stream as instructed by the geologist.

The samples are then transferred to an outside assay lab by NGM personnel. Occasionally samples

are assayed in the onsite lab if external backlogs would significantly impact the timing of results.

RC samples are normally collected on five-foot intervals. Samples pass from the drill through a

rotary wet splitter into the sample bag. Rotary splitters are typically fitted with multiple sample

outlets to allow for collection of duplicate samples. A small fraction of each five-foot sample is

caught with a sieve and placed in chip trays to be logged by geologists. The driller maintains

appropriate sample size by regularly monitoring and adjusting the splitter. The splitter is rinsed,

and the driller pauses drilling and cleans the hole between each sample. QAQC samples are

typically inserted at pre-determined intervals. The samples are transferred to the selected assay lab

by NGM personnel. Chip trays are transferred to geologists, who log lithology, alteration, and

mineralization data using the same software used to log core.

Drill hole collar locations are surveyed by NGM or contract surveyors. On occasion it was not

possible to complete the collar survey so planned coordinates were used. Downhole surveys of

surface holes are typically completed by a contractor using a conventional gyroscopic instrument.

Underground holes are surveyed using a Reflex EZ-Trac or FlexIT.

Recovery Factors

Recovery statistics are not available for South Arturo drill data. Core sample recovery is measured

by the driller and geologist. The data is used for rock quality description (RQD), but it has not

been applied in any way in relation to the reliability of the assay value of the sample interval. RC

sample recovery is measured indirectly by the assay lab, which weighs the sample on arrival and

after drying. This is not a direct measurement of sample recovery because sample volume is not

measured, a specific expected sample weight is not defined, sample density is variable, and

multiple factors affect proportion of material routed into the sample bag. Although the assay lab

sample mass data exists, it has not been applied in any way to geological analysis or in relation to

the reliability of the assay value of the sample interval. Sample recovery only directly applies to

assay reliability to the extent that where no sample was recovered, or the volume of sample

recovered was too small to perform an assay, no assay exists to represent the interval. This is an

inherent difficulty associated with drill data. Less than complete recovery of drill samples is

generally attributable to factors also associated with mineralization, such as fragmented or low

strength rock mass. It is generally accepted that mineralization is likely to be under-represented in

a poor recovery sample. This provides a level of safety in resource estimation because it is more

likely to result in under estimation than over estimation.



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The authors recommend that the database should be complete and organized in such a way as to

allow the calculation of recovery statistics for core holes. The authors believe drilling is carried

out in accordance with industry standards, and the South Arturo drill data is suitable for use in

resource estimation.

i-80 Gold Corp Sample Preparation, Analysis and Security


11. Sample Preparation, Analysis and Security

PM regards the sample preparation, security, and analytical procedures as adequate to support the

estimation of Mineral Resources.

Sample Preparation Procedures

Samples have been analyzed by several laboratories over the years, all of which were reputable.

The majority of analysis has been provided by ALS Minerals, American Assay Laboratory (AAL),

and internal NGM laboratories. Multiple assay methods are employed during different phases of

exploration and development, including fire assay, acid digestion, and cyanide leaching. Only fire

assay results are used for resource estimation. The general process of sample preparation for fire

assay is as follows: Samples are received by the lab, catalogued, dried and weighed. Each sample

is crushed to a specified fineness, then split down to a specified weight. The collected fraction of

sample is then pulverized to a specified fineness and placed in an envelope to be sent to the assay

facility. The prepared sample is called a pulp. The specific volume and fineness of the pulp depends

on the particular fire assay method selected. An example of a typical pulp is 100 grams of sample

pulverized to 85% passing 75 microns. A larger pulp may be prepared if multiple analyses or a

larger sample is desired, and pulverization may be adjusted depending on the geochemistry of the

sample.

Laboratory Analysis Procedures

The general process of fire assay is as follows: Pulps are received. Crucibles are placed in trays

and charged with flux formulated to the geochemistry of the sample. The purpose of the flux is to

help achieve complete melting of the sample in the assay furnace. Flux typically includes borax,

sodium carbonate, silica and lead. A specified amount of pulp is measured from the envelope and

placed in the crucible with the flux. The trays are placed in the assay furnace until the samples are

melted, or “fused”. The trays are removed from the furnace and the molten samples are poured

into molds and allowed to cool. As the slag hardens, the sample fractionates. The hardened slag is

removed from the mold and tapped with a hammer to separate the lead button (containing the

precious metals) from the lighter fraction of sample. The lead button is placed in a clay crucible

called a Cupel. Cupels absorb molten lead. The tray of cupels is placed in a cupellation furnace

and heated to the boiling point of lead, then allowed to cool. The bead of Au +- Ag remaining in

the cupel, called a prill, may then be placed in a parting cup and heated with a nitric acid solution

to dissolve the silver away from the gold. The remaining gold dore bead may then be processed

for measurement by either of two methods: Atomic absorption finish, which involves dissolving

the bead in aqua regia and analyzing the solution for gold content using an atomic absorption

spectroscopy machine; or gravimetric finish, where the bead is physically weighed on a

microbalance. The preferred method of finish depends on the grade of the sample. Gravimetric



i-80 Gold Corp.


finish provides better accuracy above a certain grade threshold, when the bead is more easily

visible to the assay technician and heavy enough to be sensed by the microbalance. For lower grade

samples spectroscopy is more accurate.

Security

Security at NGM sites is tightly controlled. Access to the site is staffed round the clock and all

persons entering or leaving are logged. Samples are bagged and tagged with Arturo generated

barcodes, tied and picked up at the beginning of each shift by NGM geotechnicians. Samples are

stored at the core shed for logging and core preparation. The commercial lab will pick up samples

on site and generate the chain of custody paperwork that is filed and kept on site.

Standards and Blanks

Blank materials used since 1990 have been sourced at a gravel pit near Maggie Creek. Blanks are

inserted at intervals of 50-feet for RC drilling and 200-feet for core. The resulting insertion rate is

2-5%.

Each sample batch contains from three to seven check samples. Project geologists review assay

results and periodically request a batch re-run and /or entire hole based on expected verses actual

results. Analysis beyond two standard deviations will require a rerun of the batch. The geologists

are responsible for the QAQC program.

Large batches of standard material are collected from NGM sites. Each batch is sent to an outside

laboratory for preparation. Each batch is tested for homogeneity against certified reference

materials (CRM) prior to being returned to NGM.

PM reviewed the results from 2,093 blank and standard reference assays submitted with South

Arturo samples. These are listed in Table 11-1 and shown graphically for selected standards in

Figure 11-1 through Figure 11-3. Most of the failures for BL-46 occurred near the end of 2017 and

results since that time have improved. GS-25 is a high-grade standard with most of the out of limit

values being below the acceptable limit.

Table 11-1 Gold Blank and Standard Summary Statistics

ID Count

Lab Mean

PPM Lab Std Dev

Out of Limit

Rate

Std. Value

PPM

BL-43 37 0.012 0.018 2.7% 0.0025

BL-44 120 0.006 0.011 0.8% 0.0025

BL-45 150 0.009 0.023 2.7% 0.0025

BL-46 487 0.063 0.716 8.0% 0.000

BL-47 9 0.003 0.000 0.0% 0.000



ID Count

Lab Mean

PPM Lab Std Dev

Out of Limit

Rate

Std. Value

PPM

BCH-DR-01 7 1.163 0.046 0.0% 1.140

BCH-DR-02 32 7.494 0.927 9.4% 7.760

BCH-OX-01 60 0.216 0.009 0.0% 0.214

BCH-OX-02 51 0.349 0.012 2.0% 0.338

BCH-OX-03 98 2.330 0.088 0.0% 2.260

BCH-OX-04 85 6.387 0.188 3.5% 6.450

BCH-OX-06 137 0.323 0.248 5.1% 0.283

BCH-SR-02 20 4.193 0.107 5.0% 4.250

BCH-SR-03 42 16.180 0.221 0.0% 15.980

BCH-SR-05 125 2.059 0.193 4.0% 2.080

BCH-SR-06 111 4.126 0.096 0.9% 4.130

CDN-GS-1V 64 1.033 0.077 3.1% 1.022

CDN-GS-2T 65 1.776 0.119 10.8% 1.749

CDN-GS-8C 20 8.600 0.185 0.0% 8.589

GS-20A 6 21.098 0.917 0.0% 8.530

GS-25 93 24.390 5.099 17.2% 21.120

GS-3S 5 3.495 0.176 0.0% 25.601

GS-4E 86 4.122 0.372 11.6% 3.579

GS-P5E 30 0.602 0.165 26.7% 4.190

GS-P6B 34 0.738 0.613 26.5% 0.655

ME-1708 69 6.686 1.149 4.3% 0.624

SJ80 6 2.255 0.558 33.3% 6.967

SK78 15 4.053 0.114 0.0% 2.656

SP73 10 17.590 0.582 10.0% 4.134

2,093 6.0%



i-80 Gold Corp.


Figure 11-1 Blank Assay Results BL-46

Figure 11-2 GS-25 Standard Reference Material Results



Figure 11-3 BCH-OX-06 Standard Reference Material Results

Duplicate Assays

PM reviewed the results of 1,356 South Arturo duplicate assays performed at ALS. The review

included four assay methods for gold. Data from two of these are displayed graphically in Figure

11-4 and Figure 11-5.



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Figure 11-4 821 Prep Duplicates - ALS Method AA23

Figure 11-5 488 Prep Duplicates - ALS Method AuCN AA13

i-80 Gold Corp Data Verification


12. Data Verification

The authors have not conducted an independent review of the drill database. A significant

proportion of the drill holes in the South Arturo area are historic. Raw data certificates are not

easily available. Significant economic production has occurred in the South Arturo area, so mine

production data sets are available for reconciliation with mineral resource models. The data

reconcile fairly well, which is a strong indication that the drill data are accurate.

All project data is stored in a GeoScience database on SQL Database server, current database

structure is acQuire. Drill hole data was converted to acQuire™ software beginning in 2008 from

in-house databases. The exploration and underground databases were used until 2017 when these

were combined with the Arturo database to form a single Goldstrike site-wide database. Assay

data is imported directly from laboratory certificates or direct laboratory SSIS packages for internal

labs. Data is validated and checked upon import by the data management group. Data must be

approved by project geologists before it is available for export for use in mineral resource

modeling.

Nevada Gold Mines utilizes integrated sub-programs called “Triggers” and “Constraints” that

automatically validates data whenever new information is added to, or changed within, the

database. These sub-programs perform calculations, validation, verification, and range bound

checks on the data to ensure that data errors are flagged and kept out of the data sets. Data

extractions are accomplished using the acQuire export object and checked against previous exports

to ensure data is not being altered and that exports are exporting the same historical data. Assays

are ranked based on lab quality, assay method, and date assayed.

Database administrators perform occasional random checks to ensure that imported data matches

lab certificates. External audits have previously occurred. Lynda Bloom of Analytical Solutions

Ltd. reviewed Barrick’s Storm Resource Area QAQC results for 1999 through 2004. Her report

was not available for review. RPA 2018 noted that Bloom found no evidence of serious issues with

accuracy, bias or analytical procedures. In 2018, Todd Wakefield of Mine Technical Services Ltd,

reviewed QAQC results for South Arturo control samples submitted from April 7, 2014 through

March 5, 2018. Wakefield identified one set of blanks with an elevated failure rate and

recommended more careful sourcing of blank material. An external audit by Golder in September

2018 identified moderate risk associated with the use of conventional and non-down-hole surveyed

data (Wakefield, 2018).

The authors interviewed site personnel to gain a basic understanding of data management

procedures. The authors have reviewed QAQC data for 2017 through 2019 as reported in Section

11. Holes were checked for overlapping intervals using Vulcan, and there were none. Hole traces

were viewed in Vulcan to confirm there were no extreme downhole survey deviations.

Underground collar locations were observed to conform with mine as-built surveys. Surface collar

locations correspond with topographic surfaces where contemporary data are available, although



i-80 Gold Corp.


surface displacement has occurred since many of the holes were drilled. Lithology and mineralogy

data correspond reasonably between adjacent holes, which supports accurate hole location.

Lithology was viewed in Vulcan to confirm that the geology model conforms to the geology data.

In summary, the authors rely on positive reconciliation results, visual checks, and basic Vulcan

checks to conclude the drill data is suitable for use in the resource estimation.

i-80 Gold Corp Mineral Processing and Metallurgical Testing


13. Mineral Processing and Metallurgical Testing

Historical Metallurgical Test Work

Metallurgical testing dates to 2006 with initial testing to determine heap leach characteristics via

column tests. Further testing was completed in 2012 and 2013 as part of the BDMV, South Arturo

Project Feasibility Study. Additional testing included conventional grinding and leaching as well

as roasting and leaching tests for refractory samples.

McClelland Labs Inc. (McClelland) in Sparks, Nevada, performed column leach tests to estimate

the heap leaching performance, and Barrick’s Goldstrike Metallurgical Lab performed carbon-in-

leach (CIL) and roaster/CIL tests to estimate the CIL and roaster/CIL recovery for the South Arturo

deposit.

The metallurgical test results determined the following:

• Sulfide ore and ore containing preg-robbing organic carbon above the target cut-off gold

grade would be roasted.

• Oxide ore above the target cut-off gold grade would be processed via ROM heap leach.

• Ore containing preg-robbing organic carbon below the cut-off grade gold grade for roasting

will be considered waste.

The mill recovery ranges from 48% to 92% depending on the process employed. Recovery may

be higher than predicted if the ore is ground finer than 80% passing 200 mesh (74 µm). Previous

gold deportment studies and metallurgical test results indicated that a large portion of the gold is

most likely encapsulated in silica.

2017 Metallurgical Samples

Metallurgical tests were completed on Arturo Phase 1 and Phase 3 Pit samples that were drilled in

2017. Phase 1 holes were identified as BD17-01, BD17-02, BD17-03, BD17-04, BD17-05, BD17-

06, and BD17-07. Phase 3 holes were identified as ART17-01, ART17-02, ART17-03, ART17-

04, ART17-06, and ART17-07. Drill hole locations are shown in Figure 13-1.

Column tests were completed at McClelland Laboratories in Reno, Nevada while the standard

leach tests and bench top roasting tests were completed at Barrick Goldstrike Metallurgical

Laboratories.



i-80 Gold Corp.


Figure 13-1 South Arturo Phase 1 and Phase 3 Pit Metallurgical Drill Hole Locations

(Nevada Gold Mines 2020)

Phase 1 drill holes had a total of 408 samples, with 187 of those samples classified as heap leach

for the purposes of the testing program, had a head grades between 0.003 to 0.030 oz./ton; thirty-

six (36) samples, classified as mill grade, had head grades higher than 0.030 oz./ton. All remaining

samples were classified as waste and not tested.

Phase 3 drill holes had a total of 426 samples. Two hundred and thirty-nine (239) of those samples,

were classified as heap leach with head grade between 0.003 to 0.030 oz./ton; one hundred and

thirty-nine (139) samples, classified as mill grade with head grades above 0.030 oz./ton with

remaining classified as waste and not tested.



Nine of the Phase 3 samples with sulfide grades above 0.2% were subjected to bench top roaster

(BTR) tests. This included both heap leach grade and mill grade samples.

Composites for the column tests were compiled based on preliminary mining plans. Where

possible mining separation could occur, mill grade material was eliminated from the composite.

Five Phase 1 composite samples and eight Phase 3 composite samples were assembled for the

column testing program.

Gold recovery via cyanide leaching processes, i.e., heap leaching or CIL, is commonly a function

of cyanide solubility of the gold. Gold assaying using cyanide solubility assays (AA) and fire assay

(FA) methods are performed on drill core intervals. From these assays, the cyanide solubility ratio

(AA/FA) is used to estimate gold recovery for all ore samples. In the case of the South Arturo

Mine, gold recovery via cyanide leaching appears to be a function of both the cyanide solubility

ratio and the amount of silica contained in the samples based on data generated from early

metallurgical testing. The roaster recovery has been previously shown to be a function of only the

silica concentration. However, earlier BTR on monthly composites from West Button Hill ore did

not shown a strong correlation between gold recovery and silica, but the recovery continues to be

a function of the head grade.

Table 13-1 Number of Additional Metallurgical Tests in 2018

Test ID Phase 1 Phase 3

Bottle Rolls Leach Tests (-200 mesh) 223 378

Coarse Bottle Rolls Leach Tests (-6 mesh) 223 378

Column Tests (3/4) 5 8

Coarse Bottle Rolls Leach Tests (-10 mesh) 5 8

BTR 0 9

Column Leach Tests

Thirteen column leach tests and coarse bottle roll tests were performed at McClelland in 2018.

The Phase 1 sample results generally showed poor amenability to coarse particle size leaching at

both 80%-10 mesh (2 mm) and 80%-3/4” (19.1 mm). Gold recoveries ranged from 17% to 50%

and 17% to 39% respectively at 10 mesh and -3/4”. The -3/4” average gold recovery was 31%.

Silver recoveries in the column leach tests is very low, ranging from 3% to 25% and 6% to 10%

respectively at 10 mesh and -3/4” respectively.

The Phase 3 sample results generally showed better amenability to coarse particle size leaching at

both 80%-10 mesh and 80%-3/4”. Gold recoveries ranged from 38% to 80% and 18% to 92%

respectively at 10 mesh and -3/4”. The -3/4” average gold recovery was 62%. Silver recoveries in

the column leach tests is very low, ranging from 5% to 33% and 2% to 50% respectively at 10

mesh and 3/4” respectively.



i-80 Gold Corp.


CIL Bottle Roll Tests

The CIL bottle roll test work was performed at Barrick’s Goldstrike Metallurgical Lab in 2017 and

2018 using targeted grinds of 80% passing 6 mesh (3.35 mm) and 200 mesh (74 µm). Composites

for bottle roll tests at Goldstrike’s Metallurgical Laboratory were assembled within each drill hole

to test leaching parameters at silica and carbonate geological designations. Gold generally was

found to occur within high silica areas, but recovery seemed to be more affected by sulfide

concentration.

The Phase 1 results are shown in Table 13-2 segregated by the two grade ranges (<0.03 oz./ton to

heap leach; >0.030 oz./ton for mill processing). Phase 1 mill material leached at 80% passing 200

mesh shows that recovery can range from 67 to 84%, averaging 74%. The low-grade samples

leached at 6 mesh, showed recoveries ranging from 22% to 62%, averaging 46%. The low

recoveries for some samples indicate that heap leaching processing may not be economic.

Table 13-2 Arturo Phase 1 CIL/Leach Tests for Low Grade and High Grade Samples

Process

Route Composite

Leach Tests Feed Assays

No. of

Samples

Calculate

d Head

(oz./ton

Au)

-200

mesh CIL

Recovery

(% Au)

-6 Mesh

Leach

Recovery

(% Au)

"Sulfide

Sulfur

No. of

Samples

Calculate

d Head

(oz./ton

Au)

Hea

p L

each

Gra

de

(<0

.03

0 o

z./t

on

)

BD17-01 Comp-2 18 0.021 71.7 - 0.15 4.85 0.08

BD17-01 Comp-3 12 0.020 60.7 - 0.14 1.65 0.11

BD17-02 Comp-1 3 0.003 67.1 50.0 0.05 50.36 0.02

BD17-03 Comp-1 6 0.010 79.1 38.9 0.15 8.94 0.04

BD17-03 Comp-2 5 0.012 75.9 38.2 0.14 19.83 0.05

BD17-03 Comp-3 6 0.015 73.3 34.9 0.34 15.44 0.05

BD17-04 Comp-1 11 0.006 67.2 32.5 0.06 0.25 0.11

BD17-04 Comp-2 4 0.009 55.4 24.8 1.40 0.50 0.03

BD17-04 Comp-3 8 0.005 51.9 42.9 0.41 5.85 0.05

BD17-05 Comp-1 16 0.016 81.4 62.1 0.13 4.00 0.03

BD17-05 Comp-2 16 0.014 71.4 35.9 0.17 4.50 0.05

BD17-05 Comp-3 26 0.010 71.3 36.7 0.15 6.20 0.07

BD17-06 Comp-1 18 0.011 65.0 26.1 0.29 37.87 0.02

BD17-06 Comp-2 4 0.010 69.7 33.0 0.33 21.38 0.03

BD17-06 Comp-3 6 0.023 70.2 27.8 0.28 6.44 0.05

BD17-06 Comp-4 11 0.019 68.3 21.6 0.13 6.79 0.13

BD17-07 Comp-1 13 0.018 77.7 35.7 0.02 15.69 0.03

BD17-07 Comp-2 4 0.013 84.7 37.5 0.05 17.34 0.02

Totals and Averages 187 0.013 70.1 36.2



Process

Route Composite


No. of

Samples

Calculate

d Head

(oz./ton

Au)

-200

mesh CIL

Recovery

(% Au)

-6 Mesh

Leach

Recovery

(% Au)

"Sulfide

Sulfur

No. of

Samples

Calculate

d Head

(oz./ton

Au)

Mil

l G

rad

e (>

0.0

30

oz.

/ton

)

BD17-01 Comp-1 9 0.075 67.0 - 0.22 1.85 0.05

BD17-04 Comp-4 5 0.063 76.3 23.9 0.04 0.20 0.08

BD17-05 Comp-4 2 0.161 79.2 42.3 0.01 0.20 0.02

BD17-06 Comp-5 3 0.057 69.4 28.3 0.18 8.24 0.04

BD17-06 Comp-6 2 0.046 69.6 31.4 0.15 2.25 0.13

BD17-06 Comp-7 6 0.090 71.8 29.7 0.09 0.90 0.06

BD17-07 Comp-3 3 0.051 84.4 40.2 0.02 3.60 0.02


The Phase 3 results are shown in Table 13-3 segregated by the two grade ranges (<0.03 oz./ton to

heap leach; >0.030 oz./ton for mill processing). Phase 3 mill grade samples leached at 80% passing

200 mesh shows that recovery can range from 73% to 93%, averaging 82% without roasting. The

low-grade samples leached at 6 mesh, showed recoveries ranging from 22% to 80%, averaging

43%. The low recoveries for some of these samples indicate that heap leaching processing may

not be economic.

Select low grade and mill grade samples were selected for bench-top roasting prior to CIL testing.

Samples were selected if sulfide concentration exceeded 0.2%. Two samples were selected outside

of the parameter. When the minimum sulfide grade was above the threshold, approximately 6%

recovery improvement was seen.



i-80 Gold Corp.


Table 13-3 Arturo Phase 3 CIL/Leach Tests for Low Grade and High Grade Samples

Process

Route Composite


No. of

Samples

Calculate

d Head

(oz./ton

Au)

-200

mesh CIL

Recovery

(% Au)

-6 Mesh

Leach

Recovery

(% Au)

"Sulfide

Sulfur

No. of

Samples

Calculate

d Head

(oz./ton

Au)

Hea

p L

each

Gra

de

(<0

.03

0 o

z./t

on

)

ART17-03 Comp 4 17 0.010 90.4 41.7 0.10 49.01 0.04

ART17-07 Comp 1 11 0.006 51.9 40.0 0.01 0.10 0.05

ART17-01 Comp 3 14 0.008 75.1 57.1 0.01 0.15 0.11

ART17-03 Comp 1 27 0.020 84.6 40.8 0.11 0.60 0.05

ART17-06 Comp 1 21 0.009 66.7 25.0 0.03 0.20 0.03

ART17-02 Comp 1 50 0.013 84.7 80.1 0.06 2.70 0.05

ART17-03 Comp 2 17 0.021 81.0 30.0 0.65 5.15 0.13

ART17-04 Comp 5 5 0.011 56.0 25.0 0.18 47.41 0.03

ART17-01 Comp 4 22 0.020 84.2 70.3 0.25 0.30 0.16

ART17-02 Comp 5 12 0.018 59.3 30.8 0.19 25.78 0.07

ART17-02 Comp 3 8 0.018 55.5 22.4 0.13 0.20 0.14

ART17-03 Comp 3 26 0.031 72.8 37.6 0.54 6.15 0.08

ART17-01 Comp 5 9 0.029 72.3 54.3 0.47 0.20 0.31


Mil

l G

rad

e (>

0.0

30

oz.

/to

n)

ART17-01 Comp 6 23 0.046 74.0 54.3 0.51 0.10 0.18

ART17-04 Comp 3 13 0.060 83.4 52.2 0.05 5.25 0.06

ART17-01 Comp 2 15 0.073 93.9 76.6 0.01 0.20 0.05

ART17-02 Comp 4 7 0.091 72.5 34.1 0.18 0.15 0.07

ART17-02 Comp 2 14 0.118 78.8 52.9 0.31 1.00 0.08

ART17-04 Comp 4 13 0.130 85.0 55.2 0.10 7.84 0.04

ART17-04 Comp 1 16 0.168 74.4 43.0 0.35 0.15 0.07

ART17-04 Comp 2 16 0.247 85.5 59.4 0.08 2.95 0.05

ART17-01 Comp 1 22 0.343 93.3 67.3 0.03 0.15 0.03


Recovery Estimates

Currently Arturo ore that meets the grade requirements is sent to NGM’s Goldstrike roaster for

processing. Other ore mined is stockpiled for future processing. In general, the following recovery

estimates are applied to Arturo ores:

• The LOM contains the addition of the Arturo heap leach in which metallurgical testing and

characterization is being conducted. Recovery from initial testwork has been applied and

averages 52.5%.

• The current roaster LOM has an average recovery of 88%.

• The autoclave with parallel calcium thiosulphate (CaTS) leaching-resin in leach circuits

provide a possible destination for Arturo ore. The current autoclave LOM has an average

recovery of 50% when running solely alkaline ore (one SAG-Ball Mill circuit and 3



autoclaves to process 3.6 Mtpa) and an average of 73% expected after converting the RIL

circuit to CIL and running single refractory ore.

Conclusions

The metallurgical test results determined the following:

• Column tests on Phase 1 composite samples showed gold recoveries of 17% to 39%,

averaging 31% at 80% -0.75”. At 80% passing 10 mesh, gold recoveries ranged from 17%

to 50%.

• Column tests on Phase 3 composite samples showed gold recoveries of 38% to 92%,

averaging 62% at 80% -0.75”. At 80% passing 10 mesh, gold recoveries ranged from 38%

to 85%.

• BTR results on the West Button Hill monthly composites showed a good correlation

between head grade and gold recovery – similar to the predictive model used for estimating

Goldstrike Roaster gold recovery performance. Silica encapsulation was not found to

negatively influence recovery results.

• The average gold recovery for the Phase 1 heap leach samples at 80% passing 6 mesh is

36% with a range of 22% to 62%. Mill grade average gold recovery at 80% passing 200

mesh is 74% with a range of 67% to 84%.

• Phase 3 samples showed average gold recoveries for heap leach samples at 80% passing 6

mesh of 43% with a range of 22% to 80%. Mill grade samples showed average recoveries

at 80% passing 200 mesh of 82% with a range of 73% to 94%.

• The Phase 3 high sulfide samples (>0.2%) showed an average 10% recovery improvement

over standard CIL leach at grind of 80% passing 200 mesh.

Recommendations:

• Sulphide ore and ore containing preg-robbing organic carbon above the target cut-off gold

grade is currently roasted.

• Oxide ore above the target cut-off gold grade would be processed via ROM heap leach,

when constructed.

• Ore containing preg-robbing organic carbon below the cut-off gold grade for roasting will

be considered waste.

• Additional testing should be completed in Phase 3 to quantify sufficient reserves to support

the construction of the heap leach pad.



i-80 Gold Corp.


14. Mineral Resource Estimates

Introduction

The mineral resource estimate presented herein has been prepared following the guidelines of the

Canadian Securities Administrators’ National Instrument 43-101 and Form 43-101F1 (Canadian

Securities Administrators, 2011) and in conformity with generally accepted “CIM Estimation of

Mineral Resource and Mineral Reserves Best Practices” guidelines (Canadian Instirute of Mining,

Metallurgy, and Petroleum, 2019). Mineral resources have been classified in accordance with the

“CIM Standards on Mineral Resources and Reserves: Definition and Guidelines” (Canadian

Institute of Mining Metallurgy and Petroleum, 2014 B)

• Measured Mineral Resource: “A ‘Measured Mineral Resource’ is that part of a mineral

resource for which quantity, grade or quality, densities, shape, and physical characteristics are so

well established that they can be estimated with confidence sufficient to allow the appropriate

application of technical and economic parameters, to support production planning and evaluation

of the economic viability of the deposit. The estimate is based on detailed and reliable exploration,

sampling and testing information gathered through appropriate techniques from locations such as

outcrops, trenches, pits, workings and drill-holes that are spaced closely enough to confirm both

geological and grade continuity.”

• Indicated Mineral Resource: “An ‘Indicated Mineral Resource’ is that part of a mineral

resource for which quantity, grade or quality, densities, shape and physical characteristics, can be

estimated with a level of confidence sufficient to allow the appropriate application of technical

and economic parameters, to support mine planning and evaluation of the economic viability of

the deposit. The estimate is based on detailed and reliable exploration and testing information

gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings

and drill-holes that are spaced closely enough for geological and grade continuity to be reasonably

assumed.”

• Inferred Mineral Resource: “An ‘Inferred Mineral Resource’ is that part of a mineral

resource for which quantity and grade or quality can be estimated on the basis of geological

evidence and limited sampling and reasonably assumed, but not verified, geological and grade

continuity. The estimate is based on limited information and sampling gathered through

appropriate techniques from locations such as outcrops, trenches, pits, workings and drill-holes.”

Mineral resources are not mineral reserves and do not have demonstrated economic viability.

There is no guarantee that all or any part of the mineral resource will be converted into mineral

reserve. Confidence in the estimate of Inferred Mineral Resources is insufficient to allow the

i-80 Gold Corp Mineral Resource Estimates


meaningful application of technical and economic parameters or to enable an evaluation of

economic viability worthy of public disclosure.

All mineral resource estimation work reported herein was carried out by Nevada Gold Mines

personnel.

The effective date of this mineral resource estimate is November 20, 2019. All data coordinates

are in local mine grid and quantities are given in imperial units unless indicated otherwise.

The gold and silver mineralization at the Project was estimated using Vulcan modeling software

using the Inverse Distance Cubed (ID3) estimation method with dynamic anisotropy. Multiple

estimation passes were completed. Figure 14-1 shows the block model extents.



i-80 Gold Corp.


Figure 14-1 South Arturo Block Model Extents



Modeling of Lithology and Mineralization

Modeled geological surfaces and solids were generated using Leapfrog Geo software. Data were

sourced from the drill hole database and geological mapping of the surface, pits and underground

mine areas. The cutoff date for geology data was July 31, 2019, and geology modeling work was

completed September 3, 2019. Each deposit was sub-domained into separate zones based on

multiple geological characteristics including mineralization, alteration, lithology, structure, grade

orientation and grade population data. Waste rock characterization models were also developed.

Digitized surfaces representing faults and contacts of lithological units were created by

interpolating between known points observed in drill holes and maps. Interpretation of the data

involved some editing and local smoothing to maintain sensible continuity of surfaces. The lower

surface of each lithologic unit was smoothed and clipped to ensure the interpreted sequence was

logically maintained. The lithology surfaces that were modeled are listed in Table 14-1 along with

the corresponding numeric code used in the block model.

Table 14-1 Geology Codes

Formation Name Code

Tertiary Carlin Formation 2000

Undifferentiated Tertiary Volcanics 2500

Vinini Formation 3600

Rodeo Creek Formation 4000

Popovich Formation 4200

Roberts Mountains Formation 4400

Undifferentiated Breccia 8000

Mineralization was constrained using an indicator run at low, medium and high-grade cutoffs in

Vulcan. A combination of stratigraphic unit surfaces and faults were used to define search

orientations and create directional domains. Two sets of directions were estimated into the model.

One set used fault surfaces only and the other used a blend of stratigraphic units and fault surfaces.

The fault directional set was prioritized for blocks within 100 feet of a modeled fault surface for

the medium and high-grade indicator runs. For the low-grade indicator run, only the blended

directional set was used. The indicator cutoff grades are listed in Table 14-2 along with codes for

the directional domains.



i-80 Gold Corp.


Table 14-2 Indicator Cutoff Values

Indicator Cutoff (opt)

Fault directional

code

Blend (fault and stratigraphic)

directional code

0.1 13 23

0.01 12 22

0.003 11 21

Figure 14-2 shows the medium and high-grade shells along with faults and lithology used to define

search orientations and create directional domains.

Figure 14-2 Medium and High Grade Shells with Faults and Lithology at 33500N, looking North

Drill Data and Compositing

Drill Data Set

All project data is stored in a GeoScience database on SQL Database server. The current database

structure is acQuire. Database managers export the data to be used in resource modeling as CSV

files and deliver it to the modeling group. The modeling group imports the data from the CSV files

into a Vulcan ISIS drillhole database. The drill data set used for the resource estimation contains

3,168 drill holes totaling 1,779,091 feet of drilling (Table 14-3).



Table 14-3 Drill Hole Summary

2019 year-end cutoff totals

Number of Holes 3,168

Number of Samples 279,926

Total Length (ft) 1,779,091

Compositing

Both 20-foot and 10-foot composite lengths were used at South Arturo. The 10- foot composites

were used in the mineralized area defined by a 0.003 opt Au opt indicator grade shell. The 20-foot

composites were used for estimation in the parent size blocks (40ft x 40ft x 20ft) outside of the

mineralized area. Modified length weighted compositing is used, so there is a soft boundary across

the low-grade indicator shell.

Density

A sizeable density data set for lithologies of the Carlin Trend has been amassed over the years by

various operators. The densities calculated for each rock type mined at South Arturo are listed in

Table 14-4. Adjustments are applied for non-insitu overburden such as backfill and dumps.

Tonnage estimates are completed on a dry basis. All samples are dried before specific gravity (SG)

determinations occur using various methods by on-site and off-site labs including but not limited

to submerging in water or mercury, wax and water submersion, or Zonge’s method. Zonge’s

method entails saturating samples with tap water under a vacuum, then weighing the sample in air

and water, calculating volume, drying the sample, determining dry weight then dividing dry weight

by volume to obtain bulk density.

Table 14-4 Density

Zone Density (ton/ft3)

Upper Tertiary Formation 0.0625

Non-Highly Silicified Rocks 0.0730

Highly Silicified Rocks (mostly breccia) 0.0787

Roberts Mountain Formation 0.0833



i-80 Gold Corp.


Statistics and Variography

EDA and variography were conducted by site personnel using JMP statistical software, Vulcan,

Excel, and in-house software. Variography was used to analyze the spatial continuity and relation

within each of the main domains to determine appropriate search strategies and estimation

parameters. Underground variogram properties are listed in Table 14-5 and shown in Figure 14-3

and variograms for the open pit are shown in Figure 14-4 and properties are listed in Table 14-6.

Table 14-5 Search Ellipsoid Parameters- East Deep Underground Zone

Sill (Gamma)

Major Range (ft)

Semi Range (ft)

Minor Range (ft)

0.8 48 34 38

0.9 72 50 56

1 200 145 56

Figure 14-3 Underground Zone Variaograms

Table 14-6 Search Ellipsoid Parameters - Open Pit Zones

Sill (Gamma)

Major Range (ft)

Semi Range (ft)

Minor Range (ft)

0.8 90 90 20/40

0.9 140 140 20/40

1 210 210 20/40



Figure 14-4 Open Pit Variograms

Multifactor data analysis was completed on each separate geological domain with the aim of

identifying any grade outliers, assess capping values, and validate data. General gold composite

statistics are listed in Table 14-7.

Table 14-7 Gold Composite Statistics

Rock Description Rock Code

AuFA Mean (opt)

AuFA Std Dev (opt)

AuFA Max (opt)

Coefficient of Variation

Tertiary Carlin Formation 2000 0.001 0.008 0.364 0.570

Undifferentiated Tertiary Volcanics 2500 0.001 0.003 0.079 0.522

Vinini Formation 3600 0.004 0.034 5.965 0.822

Rodeo Creek Formation 4000 0.030 0.114 5.338 0.376



i-80 Gold Corp.



AuFA Mean (opt)

AuFA Std Dev (opt)

AuFA Max (opt)

Coefficient of Variation

Popovich Formation 4200 0.001 0.021 0.572 1.414

Roberts Mountain Formation 4400 0.015 0.057 1.750 0.379

Undifferentiated Breccia 8000 0.059 0.170 5.367 0.291

Grade Capping

Exploratory data analysis (EDA) was completed on each separate geological domain with the aim

of identifying any grade outliers and to choose an optimum top cut value for each of the orientation

domains. The analysis tools applied include histogram plot, log probability plot, mean and CV

curve to look for the stability point, top 7.5% metal impact, and visual checking. Table 14-8 shows

the capping/top cut statistics and value chosen for each mineralized rock type. Grades were capped

after compositing.

Table 14-8 Composite Grade Capping


AUFA (Max) (opt)

AUFA (capped) max (opt)

Capping value (opt)

Sample Count

Samples capped

Capped %

Tertiary Carlin Formation

2000 0.364 0.2 0.2 15879 4 0.0003

Undifferentiated Tertiary Volcanics

2500 0.079 0.079 0.2 2470 0 0

Vinini Formation 3600 5.965 0.9 0.9 74249 8 0.0001

Rodeo Creek Formation 4000 5.338 2 2 95159 35 0.0004

Popovich Formation 4200 0.572 0.572 2 742 0 0

Roberts Mountain Formation

4400 1.75 1.75 2 36502 0 0

Undifferentiated Breccia

8000 5.367 2 2 49043 61 0.0012

Block Model

Estimation was completed using Inverse Distance 3 with Dynamic Anisotropy (DA). South Arturo

has utilized dynamic anisotropy to allow for a localized change in strike, dip and plunge of the

mineralization. Future model updates for other deposits will review whether the application of

dynamic anisotropy is warranted.



The block model origin was set at coordinate 0, 0, 0 with bearing 90°. The plunge and dip were

both set to zero. The model extends 12,000 feet to the north, 9,600 feet to the east, and is 3,300

feet thick. The parent block size is 40 ft x 40 ft x 20 ft with a sub block size of 10 ft x 10 ft x 10 ft

inside 0.003 opt low grade indicator cutoff areas. Underground mine depletion uses 2.5 ft x 2.5 ft

x 2.5 ft blocks which are applied after grade estimation is completed. The block model parameters

are listed in Table 14-9.

Table 14-9 Block Model Parameters

Axis Origin

(ft) Start offset

(ft) End offset

(ft) Parent Block

Size (ft)

Minimum (ft) Low Grade Indicator

Minimum (ft) Mined

North / Y 0 25200 37200 40 10 2.5

East / X 0 -7600 2000 40 10 2.5

RL / Z 0 3000 6300 20 10 2.5

Volume comparisons between the block model and the ore wireframes as well as comparison to

equipment selectivity and historic knowledge have shown, overall, that an appropriate block size

and/or sub-blocking procedure is in place.

The block model variables are listed in Table 14-10.

Table 14-10 Block Model Variables

Variable Data Type Default Value

Description

aurat Float (Real * 4) -99 cyanide solubility ratio for gold

agfa Float (Real * 4) -99 estimated silver adjusted for backfill in subblock

aufa Float (Real * 4) -99 estimated gold adjusted for backfill in subblock

auaa Float (Real * 4) -99 estimated aucn adjusted for backfill in subblock

density_rock Float (Real * 4) -99 density new adjusted to mined

ncv Float (Real * 4) -99 block net carbonate value

prclc Float (Real * 4) -99 block pregrob pct

redox Float (Real * 4) -99 block estimated redox

s2 Float (Real * 4) -99 Sulfide sulphur

s2c Float (Real * 4) -99 block s2 to co3 ratio

silica Float (Real * 4) -99 block alteration silicification btons Float (Real * 4) 0 block tons calculated from density_2 (old method

- pre MY2019)

btons_rock Float (Real * 4) 0 adjust block tons for mined and filled

aufa_orig Float (Real * 4) -99 idw estimated gold grade



i-80 Gold Corp.


Variable Data Type Default Value

Description

rock Integer (Integer * 4)

0 modified modeled strat unit and lith combined

cat Integer (Integer * 4)

0 block classification modified

zone_ug Integer (Integer * 4)

0 storm ug without pit = 1, elnino ug without pit = 2

ug_block Integer (Integer * 4)

0 inserted ug area

tg_tons Double (Real * 8) -99 Tim's ton calc

tg_zone Integer (Integer * 4)

0 Tim's slope zone

tg_silica Integer (Integer * 4)

0 silica from JH new shape

tg_redox Integer (Integer * 4)

0 oxide from JH's new shape

mined Float (Real * 4) -99 Tim's mined variable (surface only)

pit_hl_oxm_nif Integer (Integer * 4)

99 Tim's pit optimization

th_zone Integer (Integer * 4)

0 Tyler Blue Sky Zones

Grade Estimation and Resource Classification

Grade variables in the block model were estimated using inverse distance cubed (ID3) and nearest

neighbor methods. Several metallurgical variables were also estimated. Dynamic anisotropy

allows for dynamic orientation of the search ellipse to account for localized changes in strike, dip

and plunge. Directional data defined by fault and lithology surfaces are contained in a Vulcan

database structure referenced by the estimation utility. Search ellipse parameters are listed in Table

14-11 and Table 14-12.

Table 14-11 Estimation Parameters for the Underground Zone

Estimation Pass

Major Axis (ft)

Semi-Major Axis (ft)

Minor Axis (ft)

SAMPLE (MIN)

SAMPLE (MAX)

SAMPLE PER HOLE

(MAX)

PASS 2000 48 34 38 2 3 1

PASS 3000 72 50 56 2 3 1

PASS 4000 200 146 56 2 3 1

PASS 5000 300 219 56 1 3 1



Table 14-12 Estimation Parameters for the Open Pit Zones

Estimation Pass

Major Axis (ft)

Semi-Major Axis (ft)

Minor Axis (ft)

SAMPLE (MIN)

SAMPLE (MAX)

SAMPLE PER HOLE

(MAX)

PASS 2000 90 90 20 2 3 1

PASS 3000 140 140 20 2 3 1

PASS 4000 210 210 20 2 3 1

PASS 5000 300 300 20 1 3 1

Resource classification criteria are listed in Table 14-13 and Table 14-14. Mineral Resources are

classified as Measured, Indicated, and Inferred Resources based on a combination of drilling

density, geological continuity, and the variogram range continuity. All blocks that have an

estimated gold grade are subsequently classified based on the confidence in the estimation.

Table 14-13 South Arturo Underground Classification Conditions

Estimation Pass

Sample distance (ft) No. of holes Category Classification

PASS 2000 0 - 35 >= 3 1 Measured

PASS 2000 0 - 35 >= 2 2 Indicated

PASS 2000 0 - 70 >= 3 2 Indicated

PASS 2000 3 Inferred

PASS 3000 0 - 35 >= 2 2 Indicated

PASS 3000 0 - 70 >= 2 3 Inferred

PASS 3000 0 - 140 >= 3 3 Inferred

PASS 3000 4 Inventory

PASS 4000 0 - 50 >= 2 3 Inferred

PASS 4000 0 -105 >= 2 4 Inferred


PASS 5000 0 -105 >= 2 4 Inventory


Table 14-14 South Arturo Open Pit Classification Conditions

Estimation Pass

Sample distance (ft) No. of holes Category Classification

PASS 2000 0 - 40 >= 3 1 Measured

PASS 2000 2 Indicated

PASS 3000 0 - 70 >= 3 2 Indicated

PASS 3000 3 Inferred

PASS 4000 0 - 105 >= 2 3 Inferred



i-80 Gold Corp.



PASS 5000 0 - 150 >= 2 4 Inventory


Mined Depletion and Sterilization

The block model was depleted against the current open pit surface as-built and underground mined

asbuilts as of the end of September 2019. The surface as-builts are based on 3-meter topography

contours created from bi-annual third-party manned aerial surveys and updated with point cloud

surfaces with sub 1-meter accuracy created monthly from aerial drones and photogrammetry. The

as-builts of underground excavations are three-dimensional solids created from point cloud data

gathered by total stations and cavity monitoring system (CMS) laser scanners. Mined area density

and gold value were updated to reflect material removed or filled.

Model Validation

Validation procedures are undertaken on the estimations. Block coding is visually inspected after

each estimation step. Statistics of assay, composite and block model values are compared.

Estimated grades are compared to nearest neighbor grades. Block grades are visually compared to

composite grades in plan and section. Estimated ounces are compared to mined reconciliation for

mined areas. Results of the new model are compared with the previous model.

The ID3 grades were compared to nearest neighbor grades modeled in Vulcan and in-house

software. The comparison is presented in Table 14-15. The ID3 estimate is lower than the nearest

neighbor.

Table 14-15 Estimate Comparison for Au ID3 versus Nearest Neighbor

domain_dir Mean

(est_au) opt

Mean (aunn)

opt

Std Dev (est_au)

opt

Std Dev (aunn)

opt

Max (est_au)

opt

Max (aunn)

opt

CV (est_au)

opt

CV (aunn)

opt

12 0.045 0.043 0.061 0.072 2 2 0.135 0.168

13 0.257 0.247 0.226 0.259 2 2 0.088 0.105

21 0.012 0.012 0.019 0.031 1.497 2 0.154 0.248

22 0.042 0.041 0.051 0.062 1.872 2 0.122 0.154

23 0.242 0.233 0.192 0.221 1.995 2 0.079 0.095



The model can be visually checked by comparing estimated block grades to assay grades. Figure

14-5 shows a typical cross section where the block and drill color schemes match and the data

compare well.

Figure 14-5 Section View Displaying Block and Drill Grades at 33500N, looking North

Model Reconciliation

Mill to model reconciliation of the El Niño mine from inception to date shows a tonnage variance

of 2.4% and an ounce variance of -10.9% resulting in a -13.7% grade variance. Open pit mining

has historically outperformed the resource model. The Phase 2 pit ended with a positive ounce

variance of 10%. Early benches in the Phase 1 pit show an 118 % increase in tons, an 86% increase

in ounces and 15% decrease in grade. This variance is in heap leach material located at the upper

margins of the model. Additional drilling is planned this year to define the extents of the additional

mineralization (Table 14-16, Table 14-17, and Figure 14-6).

Table 14-16 Mine to Model Reconciliation

Mine Model Variance %

Ph

ase

1

Op

en

Pit

(20

19

) Tons (000’s) 1,740.1 796.9 943.1 118%

opt 0.013 0.015 (0.002) (15%)

oz. (000’s) 22.5 12.1 10.4 86%

El

Niñ

o

(20

19

) Tons (000’s) 98.1 98.3 (0.2) -0.2%

opt 0.246 0.290 (0.044) -17.9%

oz. (000’s) 26.4 28.5 (2.1) -7.9%



i-80 Gold Corp.


Mine Model Variance % E

l

Niñ

o

(20

20

) Tons (000’s) 53.1 53.2 (0.0) 0.0%

opt 0.257 0.270 (0.013) -5.1%

oz. (000’s) 16.2 14.4 1.9 11.4%

El

Niñ

o

(PT

D)1

Tons (000’s) 151.3 151.4 (0.2) -0.1%

opt 0.282 0.283 -0.001 -0.4%

oz. (000’s) 42.6 42.8 (0.2) -0.6%

1. Through March 31, 2020

Table 14-17 Mill to Model Reconciliation

Mill Model Variance %

Ph

ase

1

Op

en

Pit

(20

19

) Tons (000’s) All mineralization has been stockpiled pending heap leach

construction. opt

oz. (000’s)

El

Niñ

o

(20

19

) Tons (000’s) 109.8 98.3 11.5 10.5%

opt 0.246 0.290 (0.044) (18.0%)

oz. (000’s) 27.0 28.5 (1.5) (5.6%)

El

Niñ

o

(20

20

)1 Tons (000’s) 45.4 53.2 (7.8) (17.1%)

opt 0.257 0.270 (0.014) (5.3%)

oz. (000’s) 11.6 14.4 (2.7) (23.3%)

El

Niñ

o

(PT

D)1

Tons (000’s) 155.2 151.4 3.8 2.4%

opt 0.249 0.283 (0.034) (13.7%)

oz. (000’s) 38.6 42.8 (4.2) (10.9%)

1. Through March 31, 2020

Figure 14-6 El Niño Mill to Model Reconciliation

Source: Nevada Gold Mines



Pit Optimization

Pit optimization was carried out using the Lerch Grossman algorithm and Vulcan mine design

software. Input parameters used are the mining costs, processing costs, material routing and

variable metal recoveries, as discussed in the respective sections of this report. Pit shells in $100

increments from $600 - $1,500 were created. These are summarized in Figure 14-7 and Table

14-18. Open pit Mineral Resources are constrained by the $1,500 pit limit shown in Figure 14-8.

Figure 14-7 Pit Optimization Summary

Table 14-18 Resource Pit Shells Incremental Statistics Resource Pit $600 $700 $800 $900 $1000 $1100 $1200 $1300 $1400 $1500 Total

Process

Total

Mt 32.5 5.8 4.1 12.9 4.2 2.6 4.1 11.7 1.1 2.5 81.5

Au opt 0.048 0.035 0.041 0.050 0.033 0.028 0.030 0.034 0.023 0.024 0.041

Au Moz 1.6 0.2 0.2 0.6 0.1 0.1 0.1 0.4 0.0 0.1 3.4

Au Moz. Prod. 1.2 0.1 0.1 0.5 0.1 0.1 0.1 0.3 0.0 0.0 2.6

Recovery 78.9% 73.3% 74.5% 77.5% 70.3% 68.6% 68.9% 69.2% 65.8% 64.0% 75.7%

Roaster

Mt 8.4 1.0 1.1 3.9 1.0 0.4 0.7 1.9 0.2 0.3 19.2

Au opt 0.121 0.098 0.086 0.102 0.064 0.066 0.068 0.080 0.056 0.061 0.102

Au Moz 1.022 0.097 0.098 0.402 0.067 0.029 0.050 0.152 0.013 0.020 1.9

Mt 3.4 0.8 0.6 2.4 0.7 0.3 0.6 2.1 0.1 0.2 11.5



i-80 Gold Corp.


CIL

Mill

Au opt 0.061 0.055 0.052 0.055 0.048 0.050 0.047 0.052 0.037 0.044 0.055

Au Moz 0.210 0.046 0.033 0.134 0.034 0.016 0.030 0.110 0.003 0.011 0.6

ROM

Heap

Leach

Mt 20.6 4.0 2.3 6.6 2.5 1.8 2.7 7.7 0.8 2.0 50.9

Au opt 0.016 0.015 0.016 0.016 0.016 0.015 0.015 0.017 0.012 0.015 0.016

Au Moz 0.319 0.060 0.038 0.108 0.039 0.028 0.041 0.130 0.009 0.029 0.8

Waste Mt 197 25 30 158 27 17 34 133 7 21 650.2

Strip Ratio 6.1 4.4 7.3 12.2 6.5 6.6 8.2 11.4 6.9 8.4 8.0

Cash Flow $M $1170 $125 $91 $324 $54 $23 $29 $69 $2 $2 $1890

Figure 14-8 South Arturo Resource Pit Limit

Underground Stope Optimizer

The stope optimizer creates an excavation design everywhere the minimum stope dimensions

exceed the cutoff grade. The El N iño dimension criteria is 15x15x5 feet and the resource cutoff

grade is 0.141 opt. Stope optimizer results are shown in Figure 14-9.



Figure 14-9 El Niño Stope Optimizer Results

Mineral Resources

Table 14-19 South Arturo Mineral Resources Attributable to i-80 (Exclusive of Reserves)

Process

Tons

(000’s)

Tonnes

(000’s)

Au

(opt)

Au

(g/t)

Ag

(opt)

Ag

(g/t)

Au ozs

(000’s)

Ag ozs

(000’s)

Measured

Open Pit 5,117 4,642 0.035 1.21 0.220 7.56 180.6 1,128

Stockpile 783 710 0.016 0.55 0.013 0.44 12.4 10

Underground 18 16 0.518 17.77 0.400 13.72 9.1 7

Measured 5,917 5,368 0.034 1.17 0.193 6.63 200.2 1,145

Indicated

Open Pit 16,073 14,581 0.034 1.17 0.176 6.02 548.6 2,824

Stockpile - - - - - - - -

Underground 47 43 0.374 12.83 0.168 5.77 17.5 8



i-80 Gold Corp.


Process

Tons

(000’s)

Tonnes

(000’s)

Au

(opt)

Au

(g/t)

Ag

(opt)

Ag

(g/t)

Au ozs

(000’s)

Ag ozs

(000’s)

Indicated 16,120 14,624 0.035 1.20 0.176 6.02 566.1 2,832

Measured and Indicated

Open Pit 21,190 19,223 0.034 1.18 0.186 6.39 729.2 3,952

Stockpile 783 710 0.016 0.55 0.013 0.44 12.4 10

Underground 64 58 0.414 14.18 0.232 7.94 26.7 15

Measured and

Indicated

22.037 19,992 0.035 1.20 0.180 6.19 768.3 3,977`

Inferred

Open Pit 11,092 10,063 0.028 0.95 0.160 5.47 307.5 1,770

Stockpile - - - - - - - -

Underground 60 55 0.247 8.46 0.148 5.08 14.9 9

Inferred 11,153 10,117 0.029 0.99 0.159 5.47 322.4 1,779

Notes:

1. Mineral Resources are exclusive of Mineral Reserves;

2. Mineral Recourses are stated as of December 1, 2020;

3. Mineral Resources are estimated using variable cutoff grades that are dependent upon recovery and

processing method;

4. Open Pit Mineral Resources are constrained within a pit shell generated using a gold price of $1,500 per

ounce and a silver price of $15 per ounce;

5. Underground Mineral Resources are constrained by Mine Stope Optimizer shapes generated using a gold

price of $1,500 per ounce and a silver price of $15 per ounce;

6. Modifying mill to model factors for tons and contained metal have not been applied to the open pit

Mineral Resources;

7. Underground Mineral Resources include modifying mill to model reconciliation f0actors of 1.025 and –

0.901 applied to tons and contained metal respectively;

8. A Mineral Resource is a concentration or occurrence of solid material of economic interest in or on the

Earth’s crust in such form, grade or quality and quantity that there are reasonable prospects for eventual

economic extraction. The location, quantity, grade or quality, continuity and other geological

characteristics of a Mineral Resource are known, estimated or interpreted from specific geological

evidence and knowledge, including sampling;

9. An Inferred Mineral Resource is that part of a Mineral Resource for which quantity and grade or quality

are estimated on the basis of limited geological evidence and sampling. Geological evidence is sufficient

to imply but not verify geological and grade or quality continuity. An Inferred Mineral Resource has a

lower level of confidence than that applying to an Indicated Mineral Resource and must not be converted

to a Mineral Reserve. It is reasonably expected that the majority of Inferred Mineral Resources could be

upgraded to Indicated Mineral Resources with continued exploration; and,


i-80 Gold Corp Mineral Reserve Estimates


15. Mineral Reserve Estimates

Mineral Reserves attributable to i-80 are listed in Table 15-1. Reserves in stockpile are from the

Phase 1 and Phase II pits.

Table 15-1 Mineral Reserves Attributable to i-80 (40%)

Tons

(000’s)

Tonnes

(000’s)

Au

(opt)

Au

g/t

Ag

(opt)

Ag

(g/t)

Au ozs

(000’s)

Ag ozs

(000’s)

Proven

Open Pit 2,617 2,374 0.089 3.05 0.500 17.15 233 1,309

Stockpile 220 200 0.074 2.54 0.129 4.44 16 29

Underground 66 60 0.186 6.38 0.135 4.62 12 9

Proven 2,904 2,634 0.090 3.09 0.464 15.90 261.5 1,347

Probable

Open Pit 1,212 1,100 0.063 2.16 0.419 14.37 76.4 508

Stockpile - - - - - - - -

Underground 72 66 0.175 6.00 0.131 4.50 12.7 10

Probable 1,285 1,166 0.069 2.38 0.403 13.81 89.1 518

Proven and Probable

Open Pit 3,829 3,474 0.081 2.77 0.475 16.27 309.1 1,817

Stockpile 220 200 0.074 2.54 0.129 4.44 16.4 29

Underground 139 126 0.180 6.18 0.133 4.56 25.0 18

Proven and

Probable

4,189 3,800 0.084 2.87 0.445 15.23 350.5 1,864

Notes:

1. Mineral Reserves are stated as of December 1, 2020;

2. Mineral Reserves are estimated using variable cutoff grades that are dependent upon recovery and

processing method;

3. Mineral Reserves have been estimated at a gold price of $1,200 per troy ounce and a silver price of $15

per ounce;

4. The base case economic analysis is presented at a gold price of $1,400 per ounce and a silver price of

$15 per ounce;

5. Underground Mineral Reserves include modifying mill to model reconciliation factors of 1.14 and – 0.96

applied to tons and contained metal respectively;

6. Modifying factors for tons and contained metal have not been applied to open pit Mineral Reserves, and,

7. The reference point for mineral reserves is in situ.



i-80 Gold Corp.


Open Pit

Open pit Mineral Reserves are contained within the Phase 1 pit shown in Figure 15-1. The majority

of mineralization is on Joint Venture claims with only a minor amount extending to the north onto

NGM’s Rossi Property. Only mineralization amenable to roasting is included in Mineral Reserves.

Based on historical reconciliations at South Arturo and the diluting material incorporated in the

large 40x40x20-foot selective mining unit, no additional modifying factor for dilution is required.

Historical reconciliations for contained metal also indicate no additional modifying factor should

be applied to mining recovery. This experience is similar to that at adjacent mines on the Carlin

Trend.

i-80 Gold Corp Mineral Reserve Estimates


Figure 15-1 Mineral Reserve Pit

Underground Mineral Reserves

Excavations for underground Mineral Reserves are fully designed including necessary waste

development (Figure 15-2). The cash flow of all sequences of excavations was evaluated and

sequences with negative cash flow were removed from the reserves mine plan. Underground

reserves are refractory and are processed at the Goldstrike roaster as they are mined.



i-80 Gold Corp.


Figure 15-2 Isometric View of El Niño Underground Mine and Reserve Excavations

i-80 Gold Corp Mining Methods


16. Mining Methods

SAJV Past Production

Gold production to date under the joint venture totals 456,400 oz. The majority is from the Phase

2 (West Button Hill) pit, completed in 2017. Production from El Niño and the Phase 1 pit began

in 2019 (Table 16-1). Mining of the Phase 1 pit was suspended in December 2019 and will resume

when roasting capacity is available.

Table 16-1 South Arturo Joint Venture Gold Recovered (000's oz.)

Source 2016 2017 2018 2019 20201 Total

Phase 1 Pit - - -- 1.0 - 1.0

Phase 2 Pit 223.1 142.8 52.5 5.3 - 423.8

El Niño UG - - - 14.9 51.6 66.5

Total 223.1 142.8 52.5 21.2 51.6 491.2

1. Through December 1, 2020.

2. 100% Basis

Open Pit

The open pits are mined with a conventional shovel/truck operation. The mining equipment fleet

and support infrastructure is shared with Goldstrike. Shovel/truck requirements for the South

Arturo Phase 1 pit are listed in Table 16-2. Support equipment includes dozers, road graders, water

trucks, blast hole drills and explosives trucks.

Table 16-2 Equipment Requirements

Description Capacity Quantity

P&H 4100 Electric Shovel 80 yd3 1

Hitachi EX5500 Hydraulic Shovel 35 yd3 1

Komatsu 930 E Haul Trucks 302 ton 18-20

.

Mining benches are 20-feet high in mineralized areas and 40 feet in waste. Haulage ramps have a

maximum gradient of +/-10% and are 140-feet wide including the safety berm. Single lane ramps

are 80-feet wide and are planned for the very lowest benches. The minimum mining width is 350-

feet.

The mine operates 24 hours per day 7 days a week. Total material moved per day averages 135,000

tons with both shovels operating. The start of mining is delayed to 2025 to coincide material



i-80 Gold Corp.


delivery with roaster availability. The complete mining and processing schedule is shown in Table

16-3.

Table 16-3 Phase 1 Pit Mining and Processing Schedule

2025 2026 2027 2028 2029 2030 2031 2032

Proven and Probable Reserves Mined

Tons (000’s) 526 4,447 1,751 2,849 - - - -

Au (opt) 0.045 0.079 0.086 0.086 - - - -

Au (000’s oz) 23.9 352.2 151.4 245.3 - - - -

Waste Tons (000’s) 48,750 44,737 22,796 1,492 - - - -

Strip Ratio 92.64 10.06 13.02 0.52 - - - -

Roaster Processing

Tons (000’s) 12 557 204 333 439 451 619 -

Au opt 0.211 0.248 0.237 0.213 0.110 0.108 0.108 -

Au oz Recovered (000’s oz.) 2.2 125.2 43.7 63.5 40.1 40.3 55.3 -

2033 2034 2035 2036 2037 2038 2039 Total

Proven and Probable Reserves Mined

Tons (000’s) - - - - - - - 9,574

Au (opt) - - - - - - - 0.081

Au (000’s oz) - - - - - - - 772.8

Waste Tons (000’s) - - - - - - - 117,775

Strip Ratio - - - - - - - 12.30

Roaster Processing

Tons (000’s) - - - 524 2,369 4,830 - 10,338

Au opt - - - 0.107 0.064 0.039 - 0.079

Au oz Recovered (000’s oz.) - - - 46.6 114.8 132.2 - 663.9

100% Basis.

Material Routing

Material is routed to the process that yields the highest net income within Leco Assay constraints.

Preg-robbing assays for heap leach material must be less than 15 and S2 less than 1.5%. CIL mill

material preg-robbing values cannot exceed 40. South Arturo material with preg-robbing values

exceeding 40 is considered refractory and sent to the appropriate roaster stockpile designation

providing the grade and recovery return a positive process net income (Table 16-4 and Figure

16-1). These criteria have been successfully used on the Carlin Trend for many years.

𝑃𝑟𝑜𝑐𝑒𝑠𝑠𝑁𝐼 = (𝐴𝑢𝐹𝐴 × 𝐴𝑢 𝑟𝑒𝑐𝑜𝑣𝑒𝑟𝑦 × (𝐴𝑢 𝑃𝑟𝑖𝑐𝑒 − 𝑅𝑒𝑓𝑖𝑛𝑖𝑛𝑔 𝐶𝑜𝑠𝑡)

+ (𝐴𝑔𝐹𝐴 × 𝐴𝑔 𝑟𝑒𝑐𝑜𝑣𝑒𝑟𝑦 × 𝐴𝑔 𝑃𝑟𝑖𝑐𝑒 )) × (1 − 𝑅𝑜𝑦𝑎𝑙𝑡𝑦) − 𝑃𝑟𝑜𝑐𝑒𝑠𝑠 𝐶𝑜𝑠𝑡



Table 16-4 Arturo Material Routing

Facility Name

Route

Code AuFA AuAA

AuAA/

AuFA TCM S2

Preg

Rob NCV

Hea

p

Lea

ch

AOL 50 0.005 – 0.015

≥ 0.35

< 0.5%

< 15

AOLH 54 0.015 – 0.035

ASL 51 0.005 – 0.015 < 1.5%

ASLH 55 0.015 – 0.035

CIL

Mil

l AOML 52 0.035 – 0.05 ≥ 0.80

< 40

AOMH 53 0.05 – 0 .125

Ro

aste

r

AR10 10 0.05 – 0.08 < 1.0%

AR11 11 0.08-0.15 < 1.0%

AR24 24 > 0.085 > 1.0%

AR25 25 > 0.15 < 1.0%

ARSO-

CO3

17 0.027 – 0.085 > 0

ARSO-

PAG

19 0.027 – 0.085 < 0

AMW 49 0.022 – 0.027 < 1.0%

Was

te Inert 40 < 0.3% > 1

PAG 41 > 0.3% < 1

Inert 42 Carlin Formation < 0.3% > 1



i-80 Gold Corp.


Figure 16-1 Arturo Ore Control Flow Chart

`

AOMH

AOLH

(54)

AOML

S2 < 0.5%

PREG CALC < 40

PREG CALC < 15

FALSE

TRUE

AR25 Aufa >= 0.15TCM <1.0%

Aufa>=0.015

FALSE

FALSE

S2 < 1.5%ASLH

(55)

ASL

S2 < 0.5%

S2 < 1.5%

AOL

Aufa>=0.05

NPIHL >=NPICIL

andNPIHL>=NPIROAST

andNPIHL> 0

TRUETRUE TRUE

FALSE

FALSE

TRUETRUE

TRUE

NPICIL>=NPIROAST

and

NPICIL >0

TRUE

FALSE

FALSE

TRUE TRUE

FALSE

TRUE TRUE

FALSE

Aufa >= 0.08 AR11 TRUE

Aufa >= 0.05

FALSE

TRUEAR10

NPIROA ST >0

FALSE

TRUE

FALSE

NCV> 0%ARSO

CO3 (17)

ARSO PAG (19)

Aufa >= 0.085 AR24

FALSE

TRUE

FALSE

Aufa >= 0.027

TCM <1.0% AMW

FALSE

TRUE TRUE

TRUE

FALSE

NCV > 1% S2 < 0.3% Carlin Waste

PAG Waste

FAL

TRUE TRUE

FALSE

Rock = Carlin

Waste

TRUE

FALSE

Roaster

FAL

Waste

CIL

HL

Phase 1A



Geotechnical

Hydrogeological conditions in the Dee Pit are fully drained by NGM’s Goldstrike dewatering

program. Eight vibrating wire piezometers were installed in the area of the South Arturo/Phase 3

pit to investigate the potential of perched water in the clay rich substrate of the Carlin formation.

The piezometers indicate perched heads of 4 to 174 feet, and two perched groundwater tables were

interpreted in the upper and lower clay ash units.

Piteau and Associates analyzed structural data collected from a nine-hole geotechnical drill

program in 2007 and mapping of the Dee Pit by Call and Nicholous in 1995. The drilling program

included oriented core, acoustic televiewer logging and optical televiewer logging. Laboratory

analyzed core samples for intact rock strength, friction angle and cohesion. Figure 16-2 shows the

pit wall slope sectors and the design recommendations for each are given in (Piteau 2010).



i-80 Gold Corp.


Figure 16-2 Pit Wall Sectors

(Piteau 2010)



Table 16-5 Recommended Inter-ramp and Overall Slope Designs

Bench Design Inter-ramp/Overall Slope Design

Pit

Design

Sector

Domains

(Lithology)

Dip

Direction

Bench

Height

(feet)

Catch

Bench

Width

(feet)

Bench

Face

Angle

Inter-ramp Slope

Angle

Max Inter-ramp

Slope Height

(feet) Ramp/Stepout Width (feet)

Toe

Pushback

Distance

(feet)

No

rth

Dee

p P

it

Ph

ase

1

I Vinini 345 – 165

60

30.0 65

46 340

105 n/a

38.7 42 420

II Rodeo

Creek/Bootstrap 285 - 165 30.0 65 46 420

III Vinini 165 - 195 32.0

65 45 240

38.6 42 420

IV. Rodeo

Creek/Bootstrap 165 – 195 29.7 60 43 420

V Vinini 195 – 315 36.9 60 40 420

VI Rodeo

Creek/Bootstrap 195 – 285 36.9 60 40 420

VII Carlin 285 – 060 48.8 60 38 240

So

uth

Art

uro

Pit

Ph

ase

338

Be

VIII Breccia/Bootstrap 315 – 165

60

30.0 65 46 420

105 n/a

IX Breccia/Bootstrap 165 – 225 32.0 65 45 420

X Breccia/Bootstrap 225 285 36.9 60 40 420

XI Carlin 073 – 253

Above 5560 48.8 65 38 240

XII Carlin 073 – 253

Below 5560

Slope orientation not recommended in Carlin and should be developed in bedrock

XIII Carlin 253 - 282

60 48.8 65

34 (above 5020)

38 (below 5020)

120 (above 5200)

180 (5080 – 5200)

240 (Below 5080)

105 (3 ramps/stepouts) n/a

044 – 073 105 (4 – 5 ramps/stepouts)

XIV Carlin 282 - 044 60 48.8 65

37 (above 5020) 120 (above 5200)

180 (5020 – 5200)

240 (below 5200)

105 (3 – 4 ramps/stepouts) 175 ft. south

38 (below 5020)



i-80 Gold Corp.


Underground

Mine Development

16.3.1.1. Access Development

Access to the El Niño underground mine is through 2 portals located in the bottom of the phase 2

open pit. Dimensions of the major access development drifts are 16-feet wide x 17-feet high. Major

access drift gradients do not exceed +/-15%.

Figure 16-3 El Niño Plan View Showing Portals and Main Ramp

Mining Methods

Underhand drift and fill mining is the preferred mining method at El Niño. Attack ramps and

production drift dimensions are 15-feet x 15-feet. Attack ramps are driven from the main

development to the mineralization boundary. Attack ramps may have a gradient of +/-15%,

however, production drifts are preferred level. Once completed, a drift is backfilled with cemented

rock fill (CRF) allowing the adjacent drift to be excavated. This process of drifting and backfilling

is repeated until all economic mineralization has been mined in a 15-foot thick vertical horizon.

Sample drilling the ribs helps define the boundaries. Where the remining mineralization does not

justify the excavation of another drift the ribs may be slabbed to recover the mineralization before

backfilling.

To initiate the next drift and fill horizon either a new attack ramp is driven, or the sill of the

previous attack ramp is mined to reach the next drift and fill level elevation. Drifts under or



alongside fill require less ground support than drifts entirely surrounded by rock. Drifts under fill

can be widened to widths up to 20-feet.

Ground Support

The ground conditions at El Niño are typical of the northern Nevada extensional tectonic

environment. Joint spacing varies from a few inches to a foot or more. Primary ground support

includes 6-gauge 3-inch x 3-inch wire mesh, and 8-foot expandable rock bolts installed on a 4-foot

x 4-foot pattern. Intersections are supplemented with 12-foot heavy duty expandable bolts installed

on a 6-foot x 6-foot pattern. Development excavations have one or two coats of shotcrete applied

at 2-inches thick per coat. Shotcrete is applied to production excavations as needed.

Cemented Rock Fill

Cemented rock fill (CRF) is mixed on the surface and hauled underground in the same trucks used

to haul broken rock to the surface. A truck will dump its load of CRF in the drift being filled and

a load haul dump (LHD) or dozer fitted with a “Jammer” attachment will push the CRF tight to

the back and ribs eliminating all void spaces. Mining alongside fill can occur as early as seven

days following its placement and usually less than 28 days to mine underneath.

A backfill plant located on the surface near the portals produces a cement slurry at a specified

water cement ratio. Commercial cement admixtures can be added if desired. Once the slurry is

fully mixed it is sprayed into a pit containing the required volume of aggregate to achieve the

desired cement content of the final product. A rubber-tired loader then mixes the slurry and

aggregate to achieve a uniform product before loading a haul truck for transport underground.

Aggregate is crushed and screened at a plant near the Meikle Mine and trucked to El Niño. The

aggregate is combined with 8% Portland cement by weight to reach a target strength of 800 psi in

28 days. Standard 6-inch x 12-inch concrete test cylinders are prepared each shift at regular

intervals. Unconfined compressive strength (UCS) tests are completed after the required curing

and the results cross-referenced to the corresponding backfill location. If the results indicate

substandard fill strength additional precautions are implemented prior to mining underneath. To

date, the UCS test results are well above the target strength.

Ventilation and Secondary Egress

Just inside the eastern portal the main access drift splits in two. The right-hand drift contains the

main fans installed in a bulkhead. The left drift comprises an airlock. Both drifts merge just below

the airlock. The east portal acts as intake and primary escape, and the north as exhaust and

secondary escape.



i-80 Gold Corp.


Auxiliary fans intake air from the main access drift and blow through rigid or flexible ventilation

ducting to the face. Air from the face returns to the main access drift.

Dewatering

South Arturo is within the Goldstrike dewatering operations cone of depression. No dewatering is

performed on the South Arturo property.

Mine Plan

All mining at the El Niño Mine is conducted by a qualified underground mining contractor. The

mine operates 24 hours per day, 7 days per week. The production schedule is shown in Table 16-6.

Table 16-6 El Niño Production Schedule

Calendar Year 2021 2022 2024 Total Proven and Probable

Reserves

Mined (000's

Tons) 229 119 - 347

Gold Grade

(Ounce/Ton) 0.186 0.169 - 0.180

Contained

Gold (000's

Ounces)

42.5 20.1 - 62.5

Development

Footage - - - -

Waster Mined

(000’s tons) 6 1 - 21

Roaster

Processed

(000's Tons) 229 136 - 364

Gold Grade

(Ounce/Ton) 0.186 0.177 - 0.183

Recovered

Gold (000's

Ounces)

38 21 - 59

(100% Basis)

i-80 Gold Corp Recovery Methods


17. Recovery Methods

Introduction

Ore from South Arturo could be processed via one of three possible routes: ROM heap leaching

(possible in the future if economics warrant), milling and CIL, or roasting and CIL. Metallurgical

testing and mineralogical study work were conducted on various samples taken from South Arturo

to support a Feasibility Study (Barrick, 2012). The most recent metallurgical testing is described

in Section 13 Mineral Processing and Metallurgical Testing.

The majority of the precious metal production will come from ore that will be trucked to existing

NGM processing circuits located approximately eight miles (12.9) km away over mine haul roads.

Ores are classified based on gold grade, level of oxidation and refractory characteristics (e.g.

presence of preg-robbing components in ore, refractory sulfide components) which contribute to

recovery at processing facilities and is routed based on an integrated process production plan that

is devised for maximum economic returns. Generally, ores grading >0.080 oz./ton are routed to

the Goldstrike roaster.

ROM Heap Leaching

Run-of-Mine (ROM) material is segregated for future possible heap leach process if economics

justify its construction. ROM material will be placed on a permanent leach pad by haul trucks.

Cyanide solution will be applied by drip emitters. The pregnant solution will then be collected in

the pregnant solution pond and pumped to a carbon-in-column (CIC) circuit for gold recovery. The

cyanide concentration and pH of the barren solution will be adjusted prior to pumping to the heap

leach pads. Loaded carbon will be periodically removed and trucked to the Goldstrike central

carbon processing circuit for stripping and refining to recover the precious metals. Regenerated

carbon is transported to the CIC circuit at South Arturo for reuse. The possible process flowsheet

is shown in Figure 17-1. Heap Leach gold recovery is dependent on grade and cyanide solubility

ratio. Gold and silver recoveries are given by the following equations.

𝐴𝑢 𝑟𝑒𝑐𝑜𝑣𝑒𝑟𝑦 = (0.6805 ×𝐴𝑢𝐴𝐴

𝐴𝑢𝐹𝐴− 0.1207 × 𝑆𝑖 + 0.1734

𝐴𝑔 𝑟𝑒𝑐𝑜𝑣𝑒𝑟𝑦 = 0.07



i-80 Gold Corp.


Figure 17-1 Proposed Heap Leach Flowsheet


Oxide Milling

The Cortez Mill could process the oxide mill grade South Arturo ore on a campaign basis. The

process flowsheet is shown in Figure 17-2. The flowsheet includes crushing, semi-autogenous

grinding (SAG), ball milling, grind thickening, carbon-in-column (CIC) circuit for the grind

thickener overflow solution, CIL circuit, tailings countercurrent decantation (CCD) wash thickener

circuit, carbon stripping and reactivation circuits, and a refinery to produce gold doré. CIL mill

recovery is dependent on cyanide solubility and silica content. Gold and silver recoveries are given

by the following.

𝐴𝑢 𝑅𝑒𝑐𝑜𝑣𝑒𝑟𝑦 = 0.509 𝑥𝐴𝑢𝐴𝐴

𝐴𝑢𝑓𝑎− 0.027 𝑆𝑖 + 0.482



𝐴𝑔 𝑅𝑒𝑐𝑜𝑣𝑒𝑟𝑦 = 0.080 𝑥 𝐴𝑔𝐴𝐴

𝐴𝑔𝐹𝐴+ 0.298

Figure 17-2 NGM Cortez Flowsheet for Oxide Ore Processing


Roaster

The Goldstrike roaster processes 5.0 to 6.1 million tons per year and consists of primary and

secondary crushing, two parallel dry grinding circuits, two parallel dual stage fluidized bed

roasters, off-gas handling, mercury recovery systems, a slurry neutralization circuit, a carbon-in-

leach (CIL) circuit with carbon stripping, cyanide detoxification circuit, and electrowinning for

gold recovery.



i-80 Gold Corp.


Gold recovery estimates are based on both test work and operational history at both facilities with

curves utilized for both depending on operating strategy and ore characteristics. Roaster recovery

is given by the equation below.

𝐴𝑢 𝑟𝑒𝑐𝑜𝑣𝑒𝑟𝑦 = (92.027536 − 37.35906𝑒−(12.94386 𝑥 𝐴𝑢𝐹𝐴))/100

𝐴𝑔 𝑅𝑒𝑐𝑜𝑣𝑒𝑟𝑦 = 0.10

South Arturo ore has been processed through the Goldstrike roaster circuit co-mingled with other

ores to optimize recoveries and throughput. The simplified Goldstrike Roaster process flowsheet

is shown in Figure 17-3.

Figure 17-3 Goldstrike Roaster Simplified Flowsheet


Autoclave

The Goldstrike autoclave circuit processes 4 - 5 million tons per year and consists of primary

crushing, two parallel semi-autogenous grinding (SAG) Mill-Ball Mill grinding circuits with

pebble crushing, five parallel autoclaves capable of acid pressure oxidation (POX) and three of

which are capable of alkaline POX, two parallel calcium thiosulphate (CaTS) leaching circuits



with resin-in-leach (RIL), electrowinning for gold recovery, and a refinery producing doré bullion

from both autoclave and roaster circuits.

Gold recovery estimates are based on both test work and operational history at both facilities with

curves utilized for both depending on operating strategy and ore characteristics.

The current autoclave LOM has an average recovery of 50% when running solely alkaline ore (one

SAG-Ball Mill circuit and 3 autoclaves to process 4.0 million tons per year) and an average of

73% after converting the RIL circuit to CIL and running single refractory ore. The average LOM

gold recovery is 65%. The simplified Goldstrike POX flowsheet is shown in Figure 17-4.

Figure 17-4 Goldstrike Pressure Oxidation Simplified CaTS-RIL Flowsheet




i-80 Gold Corp.


18. Infrastructure

Dewatering

Dewatering facilities are located at the Goldstrike operation. South Arturo mineralization is above

the cone of depression created by dewatering at Goldstrike and Meikle.

Electrical Power

Electrical power is supplied to the site from the NVEnergy grid. Site facilities include a 120kv to

13.8 kv substation and 13.8 kv distribution lines.

Water

Water is supplied by truck from Goldstrike and transferred to a 1,000,000-gallon storage tank

above the mine. A new supply well will be required if a heap leach facility is constructed.

Underground Mine Facilities

The location of the El Niño surface facilities is shown in Figure 18-1. Portal facilities include:

• Contractors office;

• Mobile equipment maintenance shop;

• Backfill mixing plant;

• Electrical distribution;

• Lined mined material storage pads;

• Storm water collection ponds; and

• Supply storage Conex containers.

Facilities located near the Meikle mine include the backfill aggregate plant and change room for

the contractor.

i-80 Gold Corp Infrastructure


Figure 18-1 El Niño Facilities Layout

Surface Mine Facilities

Facilities in support of open pit mining located at South Arturo include:

• Fenced explosive storage with two 100-ton bins;

• Site communications systems;

• Security badge operated access gates;

• Mined mineralized material stockpile areas;

• Waste rock disposal facilities;

• Storm water control facilities; and

• Mine access and haulage roads.

Additional support and maintenance facilities for surface mining equipment are located at

Goldstrike.



i-80 Gold Corp.


19. Market Studies and Contracts

Precious Metal Markets

Gold and silver are fungible commodities with reputable smelters and refiners located throughout

the world. In 2019 gold prices began increasing after several years of stagnation. Gold prices

increased from $1,292 per ounce in January 2019 to $1,968 per ounce in August 2020. As of

December 2020, the 36-month trailing average gold price was $1,477 per ounce while the average

price during that same month was $1,857 per ounce. The silver price trend shows similar behavior

prior to 2019 with the price trend remaining flat through the early 2020. The 36-month trailing

average silver price is $17.47. Historical plots for both are shown in Figure 19-1.

Figure 19-1 Historical Monthly Average Gold and Silver Prices and 36 Month Trailing Average

i-80 Gold Corp Market Studies and Contracts


Contracts

NGM has entered into a mine development and production agreement with a reputable

underground mining contractor. Practical Mining has reviewed this agreement and found it to meet

generally acceptable terms, conditions and unit costs for underground mining in northeast Nevada.

Through the normal course of business NGM will contract for services and supplies for the South

Arturo project. These activities include exploration drilling, assaying, reclamation and other

services. These are customary practices in the area.



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20. Environmental Studies, Permitting and Social or Community Impact

The Mine has developed an Environmental Management System (EMS) for operation.

ISO14001:2015 standards have been implemented for the Mine as part of the Goldstrike EMS.

The system was certified under the ISO14001:2015 standard in October 2017.

Environmental Studies and Issues

Potential impacts on water quality will be mitigated in accordance with an approved plan.

Mitigating measures include water quality monitoring, treatment of unsuitable water quality prior

to discharge, and re-assessment of forecasted water quality conditions every five years. To date,

the most significant environmental impact is anticipated to be the pit lake water quality after

mining ceases.

Social or Community Impacts

NGM’s partners have operated in the community since 1961 and are committed to involving local

organizations and community groups in discussions regarding the impact of operations on the

community. South Arturo will provide mining employment for the area and negative impacts to

the community are not foreseen

Permitting

NGM’s environmental group is responsible for permitting activities. Activities are coordinated

through the Elko Bureau of Land Management (BLM) office and Nevada Division of

Environmental Protection (NDEP) in Carson City. BLM issued its record of decision on the South

Arturo environmental impact study in 2014 and all required permits for the operation are in place.

Major permits are listed in Table 20-1.

Table 20-1 Arturo Project Significant Permits

Permit Name Number Agency Description

Plan of Operations

NVN-

087946

NVN-

070250

NVN-

071216

BLM

Plan of Operations is required for all mining and processing

activities and exploration exceeding 5 acres of surface

disturbance on public lands managed by the BLM. The BLM

approves the plan and determines the required environmental

studies, usually an Environmental Assessment (EA) or an

Environmental Impact Statement (EIS) based on the

requirements outlined in the National Environmental Policy Act

(NEPA).

National

Environmental

Policy Act -

Environmental

DOI-

BLM-NV-

E020-

2011-

0039-EIS

BLM

A Record of Decision (ROD) in the United States is the formal

decision on an EIS document that the BLM issues to disclose

potential impacts to the environment with applicable mitigation

measures to prevent undue and unnecessary degradation to public

lands.

i-80 Gold Corp Environmental Studies, Permitting and Social or

Community Impact


Assessment

Decision Record

Water Pollution

Control Permits

NEV2013

101,

0050005,

2004109

NDEP, BMRR

- Regulation

Branch

Water Pollution Control Permit (WPCP)

Water Rights 80341/803

42 NDWR

Water rights are issued by the Nevada Division of Water

Resources and State Engineer based on Nevada water law which

allocated rights based on appropriation and beneficial use within

the water basin. Prior appropriation (also known as "first in time,

first in right") allows for the orderly use of the state's water

resources by granting priority to parties with senior water rights.

This concept ensures the senior uses are protected, even as new

uses for water are allocated. Mining water rights are considered

temporary in nature.

Nevada

Reclamation

Permit

#355, 118,

142

NDEP, BMRR

- Reclamation

Branch

The BMRR Reclamation Branch works in coordination with the

BLM for projects on public land to establish reclamation

guidelines and a reclamation cost estimate to support project

bonding. This permit and associated bond ensures land disturbed

by mining activities are reclaimed to safe and stable conditions to

promote safe and stable post-mining land use. A permit is

required for any disturbance over 5 acres. The reclamation cost

estimate (RCE) is financially secured with a posted security. The

posted surety amount provides assurance that reclamation will be

pursuant to the approved reclamation plan in the event that the

State has to perform reclamation or is held until reclamation has

been successfully conducted.

Air Quality

Operation Permit

AP1041-

3155 NDEP, BAPC

An owner or operator of any proposed stationary source must

submit an application for and obtain an appropriate operating

permit before commencing construction or operation. Class II

Air Permit - Typically for facilities that emit less than 100 tons

per year for any one regulated pollutant and emit less than 25

tons per year of total Hazardous Air Pollutants (HAP’s) and emit

less than 10 tons per year of any one HAP.

Storm Water

Control Permit

NVR3000

00- MSW-

39602

NDEP Bureau

of Water

Pollution

Control

Storm water runoff from waste rock piles, haul roads, milling

facilities and other mine areas that have not mixed with process

solutions or other contaminant sources. Typical pollutants

include suspended and dissolved solids and minerals eroded from

exposed surfaces.



i-80 Gold Corp.


Closure and Reclamation Requirements

The reclamation plan has been approved by NDEP Bureau of Mining Regulation and Reclamation

(BMRR). Requirements include the removal of all facilities, recontouring waste rock facilities,

removal of roads and revegetation of disturbed areas and monitoring of water quality and

revegetation growth.

The most current Reclamation Cost Estimate (RCE) was approved by BMRR in February 2020 in

the amount of $32,512,581. Surety for the full amount has been secured and NGM has filed with

it with the State and BLM.

i-80 Gold Corp Environmental Studies, Permitting and Social or

Community Impact


Figure 20-1 Permitted Disturbance

(Barrick 2019)



i-80 Gold Corp.


21. Capital and Operating Costs

Capital Costs

South Arturo is an ongoing satellite operation to NGM’s Goldstrike mine and process facilities.

The Goldstrike roaster is a 5M ton per year fully operational facility and will process all of the

current reserves from South Arturo. Open pit mining will draw from the existing Goldstrike

equipment fleet and will be supported by the Goldstrike facilities and infrastructure. Table 21-1

shows capital expenditures required for the reserve mine plans. Underground development unit

costs of $1,867 per foot are taken from the underground mining contract currently in force.

Definition drilling costs are from the 2020 SAJV budget and pre-stripping unit costs are based on

budgeted mining costs.

Table 21-1 Project Capital Costs ($M)

2021 2022 2023 2024 2025 2026 Total

Phase 1 Definition Drilling (0.2) - - - - - (0.2)

Phase 1 Pre-stripping - - - - (29.5) - (29.5)

Underground Development - - - - - - -

Total (0.2) - - - (29.5) - (29.7

1. Attributable to Premier;

Operating Costs

Open Pit

Operating costs were provided by NGM. NGM allocates all costs to each site monthly based on

tons. Cost allocations include all direct, indirect and sustaining capital costs. Not included in these

costs is the 1.5% joint venture management fee charged to Premier by NGM. PM has reviewed

these costs and found them to be reasonable.

i-80 Gold Corp Capital and Operating Costs


Table 21-2 Unit Operating Costs

Item Unit Cost Units

Phase 1 Pit

Mining $ 1.54 $/ ton

Rehabilitation $ 0.08 $/ton

Processing

Arturo ROM Heap Leach $ 2.34 $ /ton

Cortex Oxide Mill

Direct Processing $ 6.55 $ /ton

General and Administrative $ 2.19 $ /ton

Over the Road Trucking $ 13.80 $ /ton

Total $ 22.54 $ /ton

Goldstrike Roaster $ 20.92 $ /ton

Refining and Sales $ 0.77 $ /ounce Au

El Niño Underground Mine

The unit mining costs presented in Table 21-3 were provided by Premier and NGM and are based

on actual costs to date and the underground mining contract. Not included in these costs is the

1.5% joint venture management fee charged to Premier by NGM.

Table 21-3 El Niño Unit Mining Costs

Item Unit Cost Units

El Niño Underground

Direct Mining $ 108.61 $/ton

Roasting $ 19.66 $/ton

Mine G&A $ 12.79 $/ton

Electrical Power $ 7.32 $/ton

El Niño Total $ 148.37 $/ton

Cutoff Grade

Cutoff grades based on the costs presented above and metallurgical recovery equations are

presented for Mineral Reserves and Mineral Resources in the Table 21-4 and Table 21-5

respectively.

Table 21-4 Reserve Cutoff Grades by Mine and Process

Open Pit Roaster Underground Roaster

Gold Price ($/oz) $1,200

Refining and Sales ($/oz) $0.77

Royalty 6% 6%

Recovery1 65.8% 88.0%



i-80 Gold Corp.


Open Pit Roaster Underground Roaster

Operating Costs ($/ton) $20.92 $148.37

Dilution Modifier - 12.1%

Sustaining Capital Included in Operating

Cutoff Grade (opt) 0.027 0.168

Roaster recovery is a function of head grade.

Table 21-5 Resource Cutoff Grades by Mine and Process

Open Pit Roaster

Open Pit

CIL Mill

Open Pit

ROM Heap

Leach

Underground

Roaster

Gold Price ($/oz) $1,500

Refining and Sales ($/oz) $0.77

Royalty 6% 4% 4% 6%

Recovery1 64.1% 80% 60% 86.0%

Operating Costs ($/ton) $20.92 $22.54 2.34 $148.37

Dilution Modifier - - 12.1%

Sustaining Capital Included in Operating

Cutoff Grade (opt) 0.022 0.020 0.003 0.137

Roaster recovery is a function of head grade. CIL and Heap Leach Recovery is a function of cyanide soluble gold

and silica content.

i-80 Gold Corp Economic Analysis


22. Economic Analysis

Constant dollar cash flow analysis is presented in Table 22-1 through Table 22-3 and graphically

in Figure 22-1 and Figure 22-2. The reserve mine plans include only roaster processing at the

Goldstrike facility. The Franco royalty is applied at the appropriate rate. Federal income taxes of

21% apply to taxable income after appropriate deductions for depreciation and depletion. The gold

percentage depletion rate is 15%.

Figure 22-1 Gold Production and Unit Costs



i-80 Gold Corp.


Table 22-1 Income Statement Attributable to i-80’s 40% Interest

2021 2022 2023 2024 2025 2026 2027 2028 2029 2030

Gold Sales $21 $12 $0 $0 $1 $68 $24 $34 $22 $22

Silver Sales $0 $0 $0 $0 $0 $0 $0 $0 $0 $0

Total Revenue $21 $12 $0 $0 $1 $70 $25 $36 $23 $23

Operating Cost ($14) ($8) $0 $0 ($1) ($35) ($17) ($5) ($4) ($4)

Refining and Sales ($0) ($0) $0 $0 ($0) ($0) ($0) ($0) ($0) ($0)

Royalties ($1) ($1) $0 $0 ($0) ($4) ($1) ($2) ($1) ($1)

Nevada Net

Proceeds

($0) ($0) $0 $0 $0 ($1) ($0) ($1) ($1) ($1)

Total Cash Cost ($16) ($8) $0 $0 ($1) ($41) ($19) ($9) ($6) ($6)

Cash Cost per

Ounce1 ($/oz)

$1,044 $999 $0 $0 $1,228 $816 $1,067 $353 $356 $358

EBITA $5 $3 $0 $0 $0 $29 $6 $27 $17 $17

Reclamation

Accrual

$0 $0 $0 $0 ($2) ($2) ($1) ($0) $0 $0

Depreciation ($0) ($0) $0 $0 ($0) ($6) ($2) ($3) ($2) ($2)

Total Cost ($16) ($8) $0 $0 ($3) ($48) ($21) ($12) ($8) ($8)

Income Tax ($1) ($0) $0 $0 $0 ($3) ($0) ($4) ($2) ($2)

Net Income $5 $3 $0 $0 ($1) $20 $3 $20 $12 $13

AISC $1,092 $1042 $0 $0 $36,119 $899 $1,129 $512 $510 $512

2031 2032 2033 2034 2035 2036 2037 2038 2039 Total

Gold Sales $31 $0 $0 $0 $0 $26 $64 $74 $0 $405

Silver Sales $0 $0 $0 $0 $0 $0 $1 $1 $0 $3

Total Revenue $30 $0 $0 $0 $0 $26 $65 $75 $0 $408

Operating Cost ($5) $0 $0 $0 $0 ($4) ($19) ($40) $0 ($156)

Refining and Sales ($0) $0 $0 $0 $0 ($0) ($0) ($0) $0 ($0)

Royalties ($2) $0 $0 $0 $0 ($2) ($4) ($5) $0 ($25)

Nevada Net

Proceeds

($1) $0 $0 $0 $0 ($1) ($2) ($1) $0 ($11)

Total Cash Cost ($8) $0 $0 $0 $0 ($7) ($25) ($46) $0 ($192)

Cash Cost per

Ounce1 ($/oz)

$358 $0 $0 $0 $0 $357 $539 $845 $0 $655

EBITA $23 $0 $0 $0 $0 $19 $40 $29 $0 $215

Reclamation

Accrual

$0 $0 $0 $0 $0 $0 $0 $0 $0 ($4)

Depreciation ($2) $0 $0 $0 $0 ($2) ($5) ($6) $0 ($30)

Total Cost ($11) $0 $0 $0 $0 ($9) ($31) ($52) $0 ($226)

Income Tax ($3) $0 $0 $0 $0 ($3) ($5) ($3) $0 ($27)

Net Income $17 $0 $0 $0 $0 $14 $29 $21 $0 $155

AISC $512 $0 $0 $0 $0 $511 $654 $1,007 $0 $863

1. Net of Byproduct Sales

2. AISC Exclusive of Corporate Costs

Table 22-2 Cash Flow Statement Attributable to i-80’s 40% Interest

2021 2022 2023 2024 2025 2026 2027 2028 2029 2030

Net Income $5 $3 $0 $0 ($1) $20 $3 $20 $12 $13

Depreciation $0 $0 $0 $0 $0 $6 $2 $3 $2 $2

Reclamation $0 $0 $0 $0 $2 $2 $1 $0 ($1) ($1)



2021 2022 2023 2024 2025 2026 2027 2028 2029 2030

Working Capital ($2) $1 $1 $0 ($0) ($5) $3 $1 $0 ($0)

Oper. Cash Flow $3 $4 $1 $0 ($0) $22 $8 $24 $13 $13

Total Capital ($0) $0 $0 $0 ($29) $0 $0 $0 $0 $0

Net Cash Flow $3 $4 $1 $0 ($29) $22 $8 $24 $13 $13

Disc. CF @ 5.0% $2.7 $3.5 $0.8 $0.0 ($22.8) $15.2 $5.2 $15.5 $8.3 $7.7

Cumulative

Disc.CF @ 5.0%

$2.7 $6.2 $7.0 $7.0 ($15.7 $0.8 $6.58 $22.6 $31.3 $39.3

2031 2032 2033 2034 2035 2036 2037 2038 2039 Total

Net Income $17 $0 $0 $0 $0 $14 $29 $21 $0 $155

Depreciation $2 $0 $0 $0 $0 $2 $5 $6 $0 $30

Reclamation ($1) $0 $0 $0 $0 $0 $0 ($0) $0 $0

Working Capital ($0) $1 $0 $0 $0 ($1) ($2) ($2) $5 $0

Oper. Cash Flow $18 $1 $0 $0 $0 $16 $32 $24 $5 $85

Total Capital $0 $0 $0 $0 $0 $0 $0 $0 $0 ($29.7)

Net Cash Flow $18 $1 $0 $0 $0 $16 $32 $24 $5 $155

Disc. CF @ 5.0% $10.2 $0.5 $0.0 $0.0 $0.0 $6.9 $13.3 $9.1 $2.1 $83.3

Cumulative

Disc.CF @ 5.0%

$50.0 $50.5 $50.5 $50.5 $50.5 $57.7 $71.7 $81.6 $83.7

Table 22-3 Financial Statistics Attributable to i-80


Gold price - base case (US$/oz) $1,400 $1,400 $1,400

Silver price - base case (US$/oz) $15 $15 $15

Mine life (years) 2.0 18 18

Mining Rate (tons/day) 600 135,000 N/A

Average grade (oz/t Au) 0.180 0.081 0.084

Average gold recovery (roaster %) 88.5% 80.8% 81.4%

Average annual gold production (koz) 12 15 16

Total recovered gold (koz) 23.5 265.6 289.1

Capital (M$) $- $29.7 $29.7

Cash cost (US$/oz)1 $1,028 $622 $655

All-in sustaining cost (US$/oz)1,3 $1,066 $845 $863

All in Costs (US$/oz)1,4 $1,066 $845 $863

Project after-tax NPV5% (M$) $7.2 $76.4 $83.7

Project after-tax IRR NA 54% NA

Payback Period NA 7.0 5.9

Profitability Index 5%2 NA 4.3 4.6

Notes

1. Net of byproduct sales;

2. Profitability index (PI), is the ratio of payoff to investment of a proposed project. It is a useful tool for

ranking projects because it allows you to quantify the amount of value created per unit of investment. A

profitability index of 1 indicates breakeven;

3. Excludes, construction capital, exploration, corporate G&A, interest on debt, and corporate taxes; and

4. Excludes exploration, corporate G&A, interest on debt, and corporate taxes; and,





i-80 Gold Corp.





plans, including future operations, future work programs, capital expenditures, discovery and production

of minerals, price of gold and currency exchange rates, timing of geological reports and corporate and

technical objectives. Forward-looking information is necessarily based upon a number of assumptions

that, while considered reasonable, are subject to known and unknown risks, uncertainties, and other

factors which may cause the actual results and future events to differ materially from those expressed or

implied by such forward looking information, including the risks inherent to the mining industry, adverse

economic and market developments and the risks identified in Premier's annual information form under

the heading "Risk Factors". There can be no assurance that such information will prove to be accurate,

as actual results and future events could differ materially from those anticipated in such information.

Accordingly, readers should not place undue reliance on forward-looking information. All forward-

looking information contained in this Presentation is given as of the date hereof and is based upon the

opinions and estimates of management and information available to management as at the date hereof.

Premier disclaims any intention or obligation to update or revise any forward-looking information,

whether as a result of new information, future events or otherwise, except as required by law.

The El Niño mine provides positive cash flow from 2021 – 2024. The only year of negative cash

flow occurs in 2025 when Phase 1 pit pre-stripping occurs. Positive cash flows resume in 2026

and continue until 2031, while high-grade mineralization is processed. The final period of positive

cash flow begins in 2036, when low-grade stockpiles are processed. (Figure 22-2).

Figure 22-2 Cash Flow Waterfall Chart



Sensitivity

The South Arturo project is a producing asset with low capital requirements, operating costs and

robust economics. The breakeven gold price at a 5% discount rate is $811/oz. The project remains

economic with 40% increases in capital or operating costs. The project’s sensitivity to variations

in gold prices, operating and capital costs is presented in Figure 22-3 through Figure 22-5.

Figure 22-3 Gold Price Sensitivity



i-80 Gold Corp.


Figure 22-4 Operating Cost Sensitivity

Figure 22-5 Capital Cost Sensitivity

i-80 Gold Corp Adjacent Properties


23. Adjacent Properties

South Arturo is located 4-½ miles north west from NGM’s Goldstrike operations. Goldstrike

includes roaster and autoclave processing facilities, open pit mine, underground mines and

complete support facilities. South Arturo is operated as a satellite mine to Goldstrike.

The Storm Mine on the adjacent Rossi property was accessed through portals in the Dee Pit.



i-80 Gold Corp.


24. Other Relevant Data and Information

The authors are not aware of any other relevant technical data or information pertaining to the

South Arturo Project necessary to make this Technical Report understandable and not misleading.

i-80 Gold Corp Interpretation and Conclusions


25. Interpretation and Conclusions


1. Multiple zones of mineralization are open along strike and down dip from previous

mineralization intercepts.

Processing and Metallurgical Testing

1. The Goldstrike Roaster will not be available for processing South Arturo open pit

refractory mineralization before 2026 and it will take approximately another 12 years to

complete processing of South Arturo refractory production.

2. Previous bottle roll and column leach tests from phase 1 composites achieved poor

recoveries. These composites were not representative of shallower oxide mineralization.

Mining and Infrastructure

1. The South Arturo open pit will be mined at 135,000 tons per day using facilities and

equipment from NGM’s Goldstrike operations.

2. Underground drift and fill mining is successfully extracting mineralization below the Phase

2 Pit.

Financials

1. Financial analysis of the South Arturo Project indicates i-80’s 40% interest has a net

present value at a 5% discount rate of US$83.7M.

2. The open pit and underground mines are independent, profitable, stand-alone operations.



i-80 Gold Corp.


26. Recommendations


1. Drill untested targets on trend with existing mineralization intercepts.

Metallurgical Testing

1. Expedite bottle roll and column leach tests from Phase 1 composites taken from shallower

oxide mineralization.

Mining

1. Develop mineral resources down dip from current El Niño underground workings.

2. If positive metallurgical testing results are achieved, accelerate construction of the leach

pad and mining of the Phase 1 pit targeting oxide mineralization.

Risks and Opportunities

The authors have identified the following risks and opportunities for the project.

Table 26-1 Project Risks

Risks Impact Mitigation Measure

Roaster availability may be

delayed

Project delays Pursue heap leach and CIL

mill opportunities

Pit slopes require flattening Increased waste stripping Reduce planned pit depth

Table 26-2 Opportunities

Opportunities Impact

Drill targets near current Mineral Resources Increased Mineral Resources

Improved heap leach and CIL recoveries in

Phase 1 Pit

Earlier processing and revenue stream,

reserve growth, increased revenue,

Underground resource conversion Reserve growth, mine expansion

Work Program

The authors recommend the following work program be adopted. The goals of the program are to:

1. Complete column and bottle roll tests on near surface Phase 1 mineralization;

i-80 Gold Corp Recommendations


2. If positive results are returned from step 1 modify the Phase 1 plan to achieve earlier cash

flow from heap leach and CIL material;

3. Reduce the risk of pit wall instability in phase 3;

4. Convert near mine resources to reserves; and

5. Extend mineralization along trend where it is not closed off by drilling or other geologic

constraints.

Table 26-3 South Arturo Work Program

Description 2021 H1 2022 H2 2022 2023

Estimated

Costs (US$M)

Metallurgical Testing $ 0.2 $ - $ - $ - $ 0.2

Phase 3 Geotechnical Study $ - $ 0.1 $ 0.1 $ - $ 0.2

Phase 1 Drilling $ 0.7 $ 0.4 $ 0.4 $ 0.8 $ 2.3

Phase 3 Drilling $ - $ - $ 0.5 $ 1.0 $ 1.5

El Nino Drilling $ 1.0 $ 0.5 $ 0.6 $ 1.1 $ 3.2

Total $ 1.9 $ 1.0 $ 1.6 $ 2.9 $ 7.4

i-80 40% attributable share



i-80 Gold Corp.


27. References

Barrick Goldstrike Mines Inc., Amendment to the Arturo Mine Plan of Operations and Reclamation Plan: 2019 Waste

Rock Disposal Facility Modification and Reconciliation, March 2019

Bureau of Land Management (BLM), Draft Environmental Impact Statement for the Arturo Mine Project, December

2012.

Bureau of Land Management Arturo Mine Project Final Environmental Impact Statement, 2014.

Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Definition Standards for Mineral Resources and

Mineral Reserves, adopted by the CIM Council on May 10, 2014.

Canadian Institute of Mining, Metallurgy and Petroleum (CIM), CIM Estimation of Mineral Resources and Mineral

Reserves Best Practice Guidelines, adopted by the CIM Council on November 29, 2019

Erwin Thomson Faillers, Mineral Title Status Report, March 4, 2020.

Goldcorp Inc, Goldcorp USA Inc. and Premier Gold Mines Ltd, Purchase and Sale Agreement, June 2, 2015.

Nevada Division of Environmental Protection, Bureau of Mining Regulation and Reclamation, Reclamation Permit

#0355, Feb. 18, 2020.

Piteau Associates USA, Recommended Feasibility Open Pit Slope Designs for the Arturo Project, March 8, 2010

RPA Inc, Technical Report on the South Arturo Mine, Elko County, State of Nevada, U.S.A., March 26, 2018.

Wakefield, Todd, Goldstrike Database Audit Summary, December 10, 2018

i-80 Gold Corp Certification of Authors


Certification of Authors


Mineral Resource Professionals

495 Idaho Street, Suite 205 Elko, Nevada 89801

(775) 345-3718 Fax (775) 778-9722

CERTIFICATE of QUALIFIED PERSON

Re: Preliminary Feasibility Study for the South Arturo Mine, Elko County, NV, dated the 25th day of

January, 2021, with an effective date of December 1, 2020 (the “Technical Report”):

I, Dagny Odell, P.E., do hereby certify that:

As of January 25, 2021, I am a consulting mining engineer at:



Elko, Nevada 89801

775-345-3718

1) I am a Registered Professional Mining Engineer in the State of Nevada (# 13708), and a Registered

Member (#2402150) of the Society for Mining, Metallurgy and Exploration (SME).

2) I graduated from The Colorado School of Mines, Golden, Colorado with a Bachelor of Science

Degree in Mining Engineering in 1985. I have practiced my profession continuously since 1985.

3) Since 1985, I have held the positions of mine engineer, chief engineer, mine superintendent,

technical services manager and mine manager at underground and surface metal and coal mines in

the western United States. The past 12 years, I have worked as a self-employed mining consultant

with clients located in North America, Asia and Africa. My responsibilities have included the

preparation of detailed mine plans, geotechnical engineering, reserve and resource estimation,

preparation of capital and operating budgets and the economic evaluation of mineral deposits.

4) I have read the definition of “qualified person” set out in National Instrument 43-101 (“NI 43-101”)

and certify that by reason of my experience and qualifications and good standing with proper

designation within a recognized professional organization fully meet the criteria as a Qualified

Person as defined under NI 43-101.

5) I am a contract consulting engineer for Premier Gold Mines Ltd. and last inspected the Arturo

Project on June 25, 2020.

6) I am responsible for preparation of Sections 1 – 6, 11, 14-16, & 18-26 of this Technical Report.

7) I am independent of the Issuer within the meaning of Section 1.5 of NI 43-101.

8) I was paid a daily rate for consulting services performed in evaluation of the Arturo Project for

Premier Gold Mines Ltd. and do not have any other interests relating to the project. I do not have

any interest in adjoining properties in the Cove area.

9) I have read NI 43-101 and Form 43-101F1, and the sections of the Technical Report for which I

am responsible have been prepared in accordance with that instrument and form.




(775) 345-3718 Fax (775) 778-9722

10) I consent to the filing of the Technical Report with any stock exchange and other regulatory

authority and any publication by them for regulatory purposes, including electronic publication in

the public company files on their websites accessible by the public, of the Technical Report.

11) As at the effective date of the Technical Report, to the best of my knowledge, information and

belief, the Technical Report contains all the scientific and technical information that is required to

be disclosed to make the Technical Report not misleading.

Dated this 25th day of January, 2021,

“Signed” Dagny Odell

___________________________

Dagny Odell, P.E.


[email protected]




(775) 345-3718 Fax (775) 778-9722

CERTIFICATE OF AUTHOR

Re: Preliminary Feasibility Study for the South Arturo Mine, Elko County, NV, dated the 25th day of

January, 2021, with an effective date of December 1, 2020 (the “Technical Report”).

I, Laura M. Symmes, SME, do hereby certify that:

As of January 25, 2021, I am a geologist at:

Practical Mining, LLC


Elko, NV 89801

1) I graduated with a Bachelor of Science degree in Geology from Utah State University in 2003.

2) I am a registered member of the Society for Mining, Metallurgy & Exploration (SME) #4196936.

3) I have worked as a geologist for a total of 17 years since my 2003 graduation from university. My

experience has been focused on exploration and production of gold deposits, including planning

and supervision of drill projects, generating data from drilled materials and making geologic

interpretations, data organization, geologic mapping, building digital models of geologic features

and mineral resources, and grade control of deposits in production.

4) I have read the definition of “qualified person” set out in National Instrument 43-101 (NI 43-101)

and certify that by reason of my education, affiliation with a professional association (as defined

in NI 43-101) and past relevant work experience, I fulfill the requirements to be a “qualified

person” for the Purposes on NI 43-101.

5) I am a contract consulting geologist for Premier Gold Mines Limited.

6) I am responsible for sections 7 - 10, 12 and 14 of this Technical Report. I last visited the

Arturo Project on June 25, 2020.

7) I am independent of Premier Gold Mines Ltd.. within the meaning of Section 1.5 of National

Instrument 43-101.

8) I was paid a daily rate for consulting services performed in evaluation of the Cove Project and do

not have any other interests relating to the project. I do not have any interest in adjoining

properties in the Cove area.

9) I have read National Instrument 43-101 and Form 43-101F1, and the Technical Report has been

prepared in compliance with that instrument and form.




(775) 345-3718 Fax (775) 778-9722

10) I consent to the filing of the Technical Report with any stock exchange and other regulatory

authority and any publication by them for regulatory purposes, including electronic publication in

the public company files on their websites accessible by the public, of the Technical Report.

11) As of the effective date of the Technical Report, to the best of my knowledge, information and

belief, the Technical Report contains all the scientific and technical information that is required to

be disclosed to make the Technical Report not misleading.

Dated this 25th day of January, 2021,

“Signed” Laura M. Symmes

________________________________

Laura M. Symmes, SME SME No. 4196936



Elko, NV 89801

775-345-3718

Fax: (501) 638-9162

[email protected]


TR Raponi Consulting Ltd.

I, Tommaso Robero Raponi, P. Eng., do hereby certify that:

1. This certificate applies to the Technical Report entitled “Preliminary Feasibility Study for the South Arturo Mine, Elko County, NV, dated the 25th day of January, 2021, with an effective date of December 1, 2020 (the “Technical Report”):

2. I am currently employed as President of TR Raponi Consulting Ltd. (Ontario Certificate of

Authorization No. 100505108) with an office at 15-223 Rebecca Street, Oakville, Ontario, L6K 3Y2;

3. I am a graduate of the University of Toronto with a BASc. in Geological Engineering, 1984. I

have practiced my profession continuously since 1984;

4. I am registered as a Professional Engineer in the Province of Ontario (Reg. No. 90225970) and the Association of Professional Engineers and Geoscientists of BC (Reg. No. 23536). I am a Professional Member (reg. No. 02641200) of the Society for Mining, Metallurgy and Exploration (SME). I have worked as an independent consultant since 2016.

5. My relevant experience for the purpose of the Technical Report is in the development, design,

commissioning and operation of mineral processing plants in Canada, United States, Mexico, Brazil, Venezuela, Surinam, Chile, Kyrgyzstan, Mongolia, Turkey, and Saudi Arabia. I have worked primarily with gold projects and operations.

6. I have read the definition of "qualified person" set out in National Instrument 43-101 (NI 43-

101) and certify that by reason of my education, affiliation with a professional association (as defined in NI 43-101) and past relevant work experience, I fulfill the requirements to be a "qualified person" for the purposes of NI 43-101. I am independent of the Issuer and related companies applying all of the tests in Section 1.5 of NI 43-101;

7. I have not conducted a site visit for this project;

8. I am responsible for Sections 1.5, 1.8, 1.9, 13, 17 and 25 - 26 of this Technical Report;

9. I am independent of the Issuer and related companies applying all of the tests in Section 1.5 of the NI 43-101;

10. I have had no prior involvement with the property that is the subject of this Technical Report; 11. As of the effective date of this Technical Report, to the best of my knowledge, information and

belief, this Technical Report contains all scientific and technical information that is required to be disclosed to make the Technical Report not misleading; and

12. I have read NI 43-101, and the Technical Report has been prepared in accordance with NI 43-

101 and Form 43-101F1.

TR Raponi Consulting Ltd. Effective Date: December 1, 2020

Signing Date: 25th day of January, 2021,

“Signed” Tommaso Roberto Raponi

Tommaso Roberto Raponi, P. Eng.

Preliminary Feasibility Study for the South Arturo Mine ...

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