Remote Monitoring

of Limestone Quarries

Saumen Karkun

Holtec Consulting, IndiaHOLTEC

Case Studies in Africa, Middle East and India

Dubai 2016HOLTEC

Changing quality

requirements

Increasing mining

constraints

Tighter planning schedules

Shrinking material resources

Inaccessibility & cost of timely,

global expertise

Today’s Challenges in Mining

Delayed corrective action

Escalating production

costs

Dubai 2016HOLTEC

� Inaccuracies caused by wider grid spacing initially employed

� Unexpected occurrences of deleterious material and land constraints

� Changes in environmental statute and quality variations in input materials and product requirements

� Ease of mining considerations of mines manager

� Inadequacy of local expertise (manpower, analytical tools, etc)

� O&M contracts which ignore resource conservation

Why Remote Monitoring ?Cost-efficient solution to dynamically optimize mine operations

Dubai 2016HOLTEC

� Permits remote monitoring of mining operations on a

dynamic (weekly/ fortnightly/ monthly) basis

� Allows flexibility in mining operations by dynamically

optimizing extraction plans

� Assures steady supply of homogenized material to

meet changing quality requirements

� Minimizes human dependency and bias

� Guarantees savings in mining costs

� Most importantly, extends deposit life

What it achieves

Dubai 2016HOLTEC

Remote Monitoring System

Remote

Expert

Sensitivity of CaO and MgO on Reserves

43.0

43.5

44.0

44.5

45.0

45.5

0

50

100

150

200

250

2.40 2.60 2.80 3.00 3.20 3.40 3.60

MgO (%)

Re

se

rve

s (

mio

t)

`

Block Model

Equipment

Scheduling

Short Term

Scheduling

Global

Optimization

Long Term

Scheduling

Blast

Hole

Mine

Layout

Site Data

Centre

Internet

Dubai 2016HOLTEC

Methodology

Raw Mix/

RoM

Parameters

Blast Hole

SchedulingBlasting

Blast Hole

Inputs

Pile

Parameters

Deposit

Block Model

Optimization

/ Long Term

Planning

Quarterly

Planning

Monthly

Planning

Blast

ModelRevised

Schedule

Weekly

PlanningFeedback

Revision of Block

Model based on

Feedback Data

Mining

Constraints

Raw Mix/

RoM

Parameters

Equipment

Availability

Equipment

Scheduling

Dubai 2016HOLTEC

Tools

Block

ModelingOptimization Long Term

Planning

Short Term

PlanningWeekly

Planning

Block Model

RevisionDeposit

Inventory

BORE HOLE

LOGGER/

DHDB

MINRES MIX DESIGN MINSCHED LAB FITVALIDATION

GEOSTAT QUARRY SCHEDULING & OPTIMIZATION SURPAC/

DATAMINESURPAC/

DATAMINE

Dubai 2016HOLTEC

1480

MARL MARGINAL GRADE LIMESTONE

GYPSUM HIGH GRADE LIMESTONE

SANDSTONE ULTIMATE PIT

Case Study 1 : North Africa

1580

1660 Problems

• Only HG Limestone was being used

• MG Limestone was being dumped as reject over

the HG Limestone area

• Mine advancement inhibited due to the OB dump

> 30 m height totalling ~ 5 mio t

• High production cost

Recommendations

• Blending of MG Limestone dumped as OB with

HG Limestone by optimization study

• Systematic sampling & analysis of dump

• Raw-mix study utilizing Marl and MG Limestone in-

situ as well as material dumped as OB

Benefits

• Increase in reserves by 29 mio t

• Enhancement of deposit life by 10 years

• Recovery ratio reduced from 1:1 to 1:0.55

• Saving of USD 2.75 mio / annum

• Minimization of equipment and man-power

• Environmentally sustainable operation

OB Dump

Dubai 2016HOLTEC

Relative Locations

CrusherCrusherCrusherCrusher

PlantPlantPlantPlant

Dubai 2016HOLTEC

Distances & Logistics

Plant

Long distance Uphill Conveyor (4)

Length 7.5 km; Altitude Difference 700 m

Crusher

Dubai 2016HOLTEC

Limestone associated with MarlLimestone associated with MarlLimestone associated with MarlLimestone associated with Marl

High grade Limestone OutcropHigh grade Limestone OutcropHigh grade Limestone OutcropHigh grade Limestone Outcrop

Material Occurrences

HG

Limestone

Marginal Grade

Limestone

Marl

Dubai 2016HOLTEC

Deposit Evaluation

� Marl: Occurs at top, highly heterogeneous and low grade

� Limestone : Heterogeneous marginal grade of about 50 m thickness overlies 30 m thick bottom high grade

� Use of marl to the extent possible to achieve:

� Lower Recovery Ratio

� Reduced Production Cost

� Enhanced Deposit Life

Dubai 2016HOLTEC

Optimization

The intervention parameters examined to effect optimization included

� LSF

� Alumina Ratio

� Silica Ratio

� SO3

Outcomes studied were reserves, recovery ratios and mining costs

Impact of LSF on Reserves

0

40

80

120

160

200

90 92 94 96 98 100 102 104 106

LSF

Reserves (in miot)

0.00

0.40

0.80

1.20

1.60

2.00

[SR=2.5 AR= 1.5]

Recovery Ratio (RR)

Limestone RR

Impact of SO3 on Reserves

0

40

80

120

160

200

0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2

SO3 %

Reserves (in miot)

0.0

1.0

2.0

3.0

4.0

[LSF=98 SR= 2.50]

Recovery Ratio (RR)

Limestone RR

Dubai 2016HOLTEC

� Optimization was achieved by enhancing AR to 1.5, keeping SR at 2.5 and limiting LSF to 0.98 and SO3 to 0.9.

� This resulted in an increase in deposit life by 10 years and a costsaving of approximately 2.2.2.2.75757575miomiomiomio USDUSDUSDUSD per annum

Gain

Reserves (mio t)/ Life (Years)

137

108

4636

0

40

80

120

160

Before Optimization After Optimization

Reserves

Life

OB Ratio/ Cost per t (USD)

0.451.02

2.00

2.70

0.00

1.00

2.00

3.00

Before Optimization After Optimization

OB Ratio

Cost

Dubai 2016HOLTEC

Blast hole sampling with appropriate geo coding is being done regularly and transmitted to Holtec’s office in India

Eastern Block Western Block

SiO2 Al2O3 Fe2O3 CaO SO3 SiO2 Al2O3 Fe2O3 CaO SO3

Mean 11.39 2.64 1.35 46.94 0.59 12.55 2.75 2.32 43.70 0.56

SD 3.40 1.20 0.94 4.72 0.21 4.70 1.27 1.28 5.04 0.18

Remote Monitoring

Dubai 2016HOLTEC

Description Output

• Short Term blast modelling based on blast

hole data and geo coding of model for

interactive use

• Scheduling with revised production plan on

fortnightly basis (if necessitated by the fresh

data from blast hole samples) for meeting

pile requirements

• Equipment placement scheduling with

revised production plan and mine

development needs

• - - - - - - - - - -

• - - - - - - - - - -

Fortnightly Production Scheduling

Dubai 2016HOLTEC

Fortnightly Production & Equipment Scheduling Report Location Blast

Nos

Bench Type

of Matl

Qty of

RoM

(MT)

Quality Remarks

SiO2 Al2O3 Fe2O3 CaO MgO LOI LSF SR AR

B1/NW 554 1 RoM 18,000 9.86 1.85 1.15 45.35 2.20 38.98 148.5 3.29 1.61Feed to

Pile

B3/SE 1002 3 RoM 20,000 13.38 2.25 2.65 43.78 0.75 37.20 104.0 2.73 0.85 Standby

Information to Site

Month Fortnight Type of M/c M/C No Capacity Face Qty to be handled

April 1

Shovel 1 6.0 cum B1/NW 18,000 T

Dumper 3,4,5 50 T B1/NW 18,000 T

Shovel 3 3.8 cum B3/SE Standby

Dubai 2016HOLTEC

Predicted versus Actual Results

Model Validation for continuous monitoring of predicted

versus actual results, based on feedback data from blast

holes

Actual versus Predicted

CADE Predicted

45

55

Predicted

35

25

0 100 20050 150 250

Actual

Blocks

CaO%

Dubai 2016HOLTEC

LIMESTONE

ULTIMATE PIT

Case Study 2 : South AfricaProblems

• Deposit was being exploited at 5% MgO cut off,

resulting in unwarranted rejection of usable

Limestone

• Deposit was not evaluated scientifically

• High SO3% content in ROM Limestone reported

Recommendations

• Deposit was scientifically evaluated by CADE

and QSO

• MgO% cut off could be raised to 8% by

optimisation of Dolomitic Limestone while

maintaining plant process parameters

• Confirmatory boreholes to validate

geological model

965

805

885

GREENSTONE

DOLOMITIC LIMESTONE

DOLERITE

Benefits

• Increase in reserves by 17 mio t

• Enhancement of deposit life by 10 years

• Saving in costs by USD 0.25 mio / annum

• Recovery ratio reduced from >1:1 to <1:0.6

Dubai 2016HOLTEC

Ultimate Pit

Case Study 3 : Middle EastProblems

• Steeply dipping Limestone was being mined

without forming benches in footwall side

• Side overburden was not being handled

• Slope failure and threat to safety

• Unable to advance to further depth due to space

constraints

Recommendations

• Confirmatory borehole to establish continuation

of limestone at depth

• Re-evaluation of the deposit and development

of a new Mine design

885

Benefits

• Scientific re-design of quarry for full

exploitation of mineral resources

• Increased reserves, extending current Plant life

and facilitating Plant expansion

• Saving in costs by USD 0.75/t

• Safety for Men and Machinery

Metamorphic

Limestone

Central

Schist

Dolomitic

Limestone

100m vertical wall

Current Pit

1,560

1,640

Dubai 2016HOLTEC

ULTIMATE PIT

Case Study 4 : Central India

Problems

• Only High grade Limestone was being

exploited leaving MG and LG Limestone

• High recovery ratio

Recommendations

• Deposit was scientifically evaluated by CADE

and QSO

• LG and MG Limestone could be utilised along

with HG Limestone

• Acquisition of additional adjoining area under

mineral concession

380

Benefits

• Utilization of MG and LG Limestone increasing

reserves and enhancing deposit life by 12 years

• Saving in production cost by USD 0.15/t

Low grade Limestone

High grade Limestone Marginal grade Limestone

Shale / Shaly Limestone

460

Dubai 2016HOLTEC

Case Study 5 : South IndiaProblems

• Limestone was being fed from 5 distantly

located (1 km to 40 km) quarries

• Heterogeneity in quality of limestone

Recommendations

• Blending of high iron containing limestone with

low iron containing limestone

• Modified target values for Silica and Alumina

Ratios

• High Sulphur limestone optimally blended with

low Sulphur limestone

• Block Model validated and mine planning

altered based on feedback from blast hole data

Benefits

• Increase in Reserves by 30 mio t

• Enhancement of deposit life by 5 years

• Recovery Ratio reduced to 1:0.11

• Cost saving of USD 0.24 mio/annum

Cement

Plant

Mine-5

Mine-3

Mine-4

1kmMine-1

Mine-2

35km

1km 40km

2km

Dubai 2016HOLTEC

Thank you

Web : www.holtecnet.com

E-Mail : ska@holtecnet.com

Address : Holtec Centre, A Block Sushant Lok,

Gurgaon 122001 - India

Telephone : +91 - 124 - 2385095, 4047900

Facsimile : +91 - 124 - 2385114, 2385116

Contact Details