MODELLING OF PIT DEWATERING AND EVAPORATION BASIN …€¦ · 1 INTRODUCTION Mineral Resources Ltd...

PARKER RANGE PROJECT

MOUNT CAUDAN IRON ORE

DEPOSIT

MODELLING OF

PIT DEWATERING AND

EVAPORATION BASIN

DISPOSAL

REPORT FOR

MINERAL RESOURCES LTD

DECEMBER 2019

Report No. 349.5.1/19/02

Rockwater Pty Ltd 349-5-1/19-02

TABLE OF CONTENTS 1 INTRODUCTION 1 2 PHYSICAL SETTING 1

2.1 LOCATION AND LICENCES 1 2.2 CLIMATE 2 2.3 LANDFORMS AND DRAINAGE 2 2.4 GEOLOGY AND HYDROGEOLOGY 2

3 MODELLING OF PIT DEWATERING 5 3.1 MODEL DESCRIPTION 5 3.2 DEWATERING RATE PREDICTION 7 3.3 WATER LEVEL PREDICTION 7

4 MODELLING OF EVAPORATION BASIN DISPOSAL CAPACITY 7 5 FINAL VOID 8 6 SUMMARY AND CONCLUSIONS 8 REFERENCES 9

Tables

Table 1: Rainfall and Evaporation Data 2

Table 2: Bore Details 4

Table 3: Constant-Rate Pumping Test Results 4

Table 4: Model Zones and Parameters 5

Table 5: Mining Schedule and Modelled Pumping Rates 6

Figures

1 Locality Map

2 Geology, Bores and Proposed Pits

3 Model Bores and Permeability Zones

4 Required and Modelled Water Level, Base-case Scenario

5 Required and Modelled Water Level, High Porosity Scenario

6 Base-case Scenario, Modelled Water Level, End Mining

7 High Storage Scenario, Modelled Water Level, End Mining

8 Evaporation Basin, Modelled Water Balance

REVISION AUTHOR REVIEW AUTHORISED ISSUED

0 PDEB PHW PDEB 5/12/2019

1 PdeB Carmelo Bella (MRL) 22/1/2020

Parker Range Iron Ore Deposit

Modelling of Pit Dewatering and Evaporation Basin Disposal Page 1


1 INTRODUCTION

Mineral Resources Ltd (MRL) purchased the Parker Range iron-ore deposit (also known as the Mt Caudan

iron-ore deposit) located nearby to Marvel Loch (Fig. 1), from Cazaly Resources in August 2019. The deposit

has a proven and probable ore reserve of 31.4Mt and is expected to produce an iron ore lump and fines

product of 56.4% iron. Current plans are for the deposit to be mined as two main pits, with each pit being

an amalgamation of two smaller pits (Fig. 2). Mining is scheduled to commence in early 2020, and at a

mining rate of 4 Mtpa will be completed by the end of 2024. The two central pits (Pits 1 and 2) will be mined

first and then backfilled during the mining of Pits 3 and 4.

The proposed Parker Range pits vary in depth between about 108 m (Pit 3) and 122 m (Pit 4), which equates

to 318 and 288 mRL, respectively (Fig. 2). As the standing water level (SWL) lies at about 362 mRL, the pits

will require substantial dewatering to enable dry-floor mining. Water requirements for dust suppression,

ore processing and other mining operations are expected to be about 18 L/s, so it would be desirable for

dewatering to be managed such that it matches the mine water requirement as closely as possible. An

evaporation basin will be constructed to dispose of any excess dewatering water, should that be necessary.

Based on the results of permeability tests conducted in RC mineral exploration holes by Rockwater (2009a),

and the drilling and test-pumping of four production bores (PKPB01-04) and four monitoring bores

(PKMB01-04) by Rockwater (2010), MRL commissioned Rockwater to construct numerical models to assess

the rate of pit dewatering and the disposal capacity of the evaporation basin. The results of the modelling

investigations are presented in this report, which will be used to assist in the preparation of a revised mining

proposal for the Parker Range Project, and possibly also with the application for a groundwater extraction

(GWL) licence.

Modelling assessments of dewatering at Parker Range have previously been undertaken by Rockwater

(2009a, 2010). However, these are largely redundant because they are based on different pit designs and

a different mining schedule from those currently proposed. The pumping test results presented in

Rockwater (2010) have also been reviewed to provide more-reliable estimates of the main aquifer

parameters for use in modelling.

2 PHYSICAL SETTING

2.1 LOCATION AND LICENCES

The Parker Range iron-ore deposit is situated about 50 km southeast of Southern Cross and 20 km southeast

of Marvel Loch (Fig. 1). Main access is via the Parker Range Road.

The area is a centre for gold mining, with large open-cuts and associated groundwater borefields having

been established at the Marvel Loch, Great Victoria, Yilgarn Star and Southern Star mines (Rockwater

2009b).

The project falls within mining leases M77/741, M77/742 and M77/746, which are held by MRL; and is

located at the western boundary of the Goldfields Groundwater Management area and the Yilgarn sub-

catchment area for DWER (Department of Water and Environmental Regulation) management purposes.

There are no known active groundwater bores in the Parker Range area (Fig. 1). The southern-most pit

(Pit 3) overlaps water reserve R 13208 (Fig. 2), but this is not in use and presumably authorisation has been

granted to mine (and dewater) in the area.




2.2 CLIMATE

The Mt Caudan area has a semi-arid climate with an irregular rainfall influenced by both the southern

temperate and northern tropical systems. Long-term climatic data recorded at Southern Cross indicate that

the area has an average annual rainfall of about 305 mm, with a maximum rainfall occurring during May to

August and a more well-defined minimum in rainfall occurring during October to December (Table 1).

Based on climatic records from Kalgoorlie, the long-term average potential evaporation of the area is about

2,650 mm, with evaporation greatly exceeding rainfall during every month of the year (Table 1).

Groundwater recharge is therefore limited, probably being restricted to short-term events during which the

rainfall exceeds evaporation.

Table 1: Rainfall and Evaporation Data

A. Long-term Average Monthly Rainfall at Southern Cross

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total

31.28 24.13 36.07 22.1 26.81 27.29 35.15 30.54 20.31 18.69 17.36 15.83 305.56

Source: Bureau of Meteorology, 1996-2019

B. Long-term Average Monthly Evaporation at Kalgoorlie

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total

387.5 302.4 266.6 174 111.6 78 86.8 117.8 174 252 319.3 372 2,642

Source: Bureau of Meteorology, 1996-2019

2.3 LANDFORMS AND DRAINAGE

The iron ore deposit occupies the northern and central sections of a narrow, subdued, northerly-trending

strike-ridge, situated about 2 km east of the Parker Range (Fig 1, 2). The strike-ridge is 3.5 km long and

attains a maximum elevation of 452 mAHD at Mt Caudan, which is about 50 m above the surrounding plain.

Surface drainage is ephemeral and occurs towards the axis of a major valley about 4.5 km to the east of the

Parker Range. The floor of the valley is occupied by a chain of salt lakes and has an elevation of about

360 mAHD (Fig. 1).

2.4 GEOLOGY AND HYDROGEOLOGY

The Parker Range Project is located at the western margin of the Parker (granitic) Dome, within the middle

section of the Southern Cross Greenstone Belt. The greenstone rocks comprise thick mafic-ultramafic

volcanic sequences, and metasediments composed of pelites, psamites and banded iron-formation (BIF)

(Cazaly 2011).

Local hydrothermal enrichment of the BIF has led to the development of the iron-ore deposit to be mined

in the four proposed pits (Fig. 2). Goethite is the dominant iron-oxide mineral, with lesser amounts of

hematite and martite, and accessory manganese and silica are common.




The goethite deposit dips at 60-70o to the west and varies in true thickness from about 10 to 70 m. The

eastern (footwall) side of the deposit is bounded by fine-grained metasediments and the western

(hangingwall) side of the orebody is bounded by amphibolite. To a depth of 100-120 m, both rock-types

have been weathered to clay and are therefore likely to have a low permeability.

Photos of diamond core show that goethitic sections of the orebody in particular are vuggy, and that the

central part of the orebody is very broken, probably associated with a series of faults which cuts the BIF

ridge at an oblique angle at Pits 1 and 2 (Fig. 2). The overall hydrogeological setting of the deposit is

therefore a narrow zone of moderate to high permeability and porosity goethitic ore, sandwiched between

weathered hangingwall and footwall rocks of low permeability. A narrow “bridge” of low permeability rocks

probably occurs along Parker Range Rd between Pits 1 and 2, where the orebody appears to be absent.

Air-lift rates in excess of 20 L/s were produced during the reaming of bores PKPB01, PKPB04 and PKPPB02

(Rockwater 2010), which are located in Pits 4, 2 and 3, respectively (Fig. 2, Table 2). Large cavities

intersected during drilling of monitoring bore PKMB04 indicate that the goethite aquifer at Pit 1 is likely to

be at least as productive.

The high permeability of the goethitic ore at Parker Range is confirmed by the results of the pumping tests

performed by Rockwater (2010). Testing of bores PKPB04 and PKPB02 appears to have been compromised

by the re-circulation of water back from the sumps used for disposal. However, on the basis of the early-

time constant-rate test data for PKPB02, the step-rate test data for PKPB04, and the complete constant-

rate test data for the other bores, it is estimated that the permeability of the orebody is 1 to 5 m/d (Table 2).

A significantly higher permeability may occur in the north of Pit 2, where the ore may be particularly highly

faulted. The core of ore material is generally too broken for the faults to be recognised.

A specific yield of 0.24 is indicated for the goethitic orebody by the drawdown in monitoring bore PKMB03

during the constant-rate test of PKPB03 (Rockwater 2010). This is similar to that of a fine- to coarse-grained

sand and is probably an order of magnitude higher than in the adjoining country rocks.

The standing water level (SWL) lies at 360–367 mAHD, which corresponds to a depth of 45-65 m below

ground level (mbgl) (Table 2). Owing to relatively high rates of infiltration, it is likely that a slight

groundwater mound had formed beneath the orebody.

The salinity of groundwater at Parker Range ranges from about 20,000 to 60,000 mg/L TDS (total dissolved

solids (Table 2). This is considerably lower than the salinity of groundwater at the nearby Great Victoria,

Yilgarn Star and Southern Star mines (Rockwater 2009b), and possibly relates to a higher rate of recharge

beneath the BIF ridge. However, the lower-salinity water probably occurs as surficial lens which will be

depleted by dewatering. Significantly higher long-term salinities are therefore expected.

It should be noted that bores PKPB01-04 are constructed of 155 mm NB Class 9 PVC, which makes them too

fragile and of insufficient diameter for in-pit dewatering. These will need to be replaced by 200 mm NB,

steel-cased bores before the start of mining.




Table 2: Bore Details

Bore Type mE mN Ground

Elev. (mAHD)

Drill Depth

(m)

TOC (magl)

PVC Casing

Top Slots (m)

Bottom Slots (m)

Airlift, Pilot Hole (L/s)

Airlift, Reaming

(L/s)

SWL (mbtc)

SWL (mAHD)

TDS (mg/L)

Ore Intersection

(m)

Bores drilled into ore and hangingwall and footwall in Pit 4 (northern end of northern pit)

PKPB01 PB 742368 6499462 407.6 120 0.5 155 CL9 62 110 3.7 15-20 47.52 360.58 59,200 0 – 108

PKMB01 MB 742347 6499460 406.6 114 0.4 50 CL12 50.5 98.5 3 46.65 360.38 0 – 100

PKPS27 EH 742158 6499234 404.1 96 NC


Modelling of Pit Dewatering Rates and Evaporation Basin Disposal Page 5


3 MODELLING OF PIT DEWATERING

Using the results of the pumping tests, and geological information; including cross-sections, lithological logs

and core photos supplied by MRL (formerly Cazaly), a simple groundwater model was constructed to assess

if a total extraction rate of 18 L/s is sufficient for dewatering of the pits, and to assess the redial extent of

drawdown that will be produced at the end of mining. The model was not calibrated. It is recommended

that this should be performed when operational pumping and water level data become available.

3.1 MODEL DESCRIPTION

The groundwater model used was Processing Modflow Pro Version X, which incorporates Modflow, the

industry-standard finite-difference groundwater model designed by the U.S. Geological Survey (McDonald

and Harbaugh 1988).

The model domain comprised a 4 x 8 km rectangle, subdivided into 420 rows and 136 columns, with the

columns aligned in a northerly direction, roughly parallel to the strike of the orebody. A grid cell size of

50 x 50 m was used, except in the area of the orebody where it was reduced to 10 x 10 m. One unconfined

model layer was used, with the dip of the orebody assumed to be vertical.

The model boundary was assigned no-flow, and the initial water level was set at 362 mAHD. Dewatering

was simulated by using a hypothetical production bore in the centre of each of the four proposed pits (PB1

in Pit 1, PB2 in Pit 2 etc.) (Fig. 3).

For the assignment of aquifer parameters, seven spatial zones were defined for the orebody and one spatial

zone was defined for the country rocks. Locations of the zones are shown in Figure 3, and details of the

aquifer parameters for each zone are provided in Table 4.

Table 4: Model Zones and Parameters

Parameter Orebody Zones Country

Rocks 1 2 3 4 5 6 7

LAYER 1

Top (mAHD) 450 450 450 450 450 450 450 450

Bottom (mAHD) 250 250 250 250 250 250 250 250

Initial Water Level (mAHD) 362 362 362 362 362 362 362 362

Hydraulic Conductivity (m/d) 0.1 2.0 5.0 0.1 10.0 2.0 0.1 0.01

Specific Yield (Base-Case Scenario) 0.05 0.15 0.15 0.05 0.2 0.15 0.05 0.01

Specific Yield (High porosity Scenario) 0.05 0.3 0.3 0.05 0.3 0.3 0.05 0.01

Two modelling scenarios were performed. The first, base-case scenario, involved using aquifer parameters

which are geologically most likely. The second, high porosity scenario, involved increasing the specific yield

of orebody zones 2, 3, 6 and 7, from 0.15 or 0.2 to 0.3, which given the results of the pumping test of

PKPB03, seems possible.

Three model stress periods were used based on a mining schedule provided by MRL. These are shown in

Table 5 and described briefly below.




Table 5: Mining Schedule and Modelled Pumping Rates

Year Quarter Cumm Days

Pit Floor Elevation (mRL) Model Stress Period

Base-case Scenario, Pumping Rate (L/s) High Porosity Scenario, Pumping Rate (L/s)

Pit 2 Pit 1 Pit 3 Pit 4 Bore 2 Bore 1 Bore 3 Bore 4 Total Bore 2 Bore 1 Bore 3 Bore 4 Total

2020 2 91 408 450 432 414 1 15 8 0 0 23 18 12 0 0 30

2020 3 183 402 420 432 414 1 15 8 0 0 23 18 12 0 0 30

2020 4 274 390 408 432 414 1 15 8 0 0 23 18 12 0 0 30

2021 1 365 378 402 432 414 1 15 8 0 0 23 18 12 0 0 30

2021 2 456 360 402 432 414 1 15 8 0 0 23 18 12 0 0 30

2021 3 548 330 402 432 414 1 15 8 0 0 23 18 12 0 0 30

2021 4 639 306 396 432 414 1 15 8 0 0 23 18 12 0 0 30

2022 1 730 306 384 432 414 2 0 6 4 8 18 0 12 6 10 28

2022 2 821 306 372 432 414 2 0 6 4 8 18 0 12 6 10 28

2022 3 913 306 360 432 414 2 0 6 4 8 18 0 12 6 10 28

2022 4 1,004 306 336 420 414 2 0 6 4 8 18 0 12 6 10 28

2023 1 1,095 306 306 408 402 2 0 6 4 8 18 0 12 6 10 28

2023 2 1,186 306 306 396 390 3 0 0 8 6 14 0 0 8 10 18

2023 3 1,278 306 306 384 384 3 0 0 8 6 14 0 0 8 10 18

2023 4 1,369 306 306 360 372 3 0 0 8 6 14 0 0 8 10 18

2024 1 1,460 306 306 318 360 3 0 0 8 6 14 0 0 8 10 18

2024 2 1,551 306 306 318 342 3 0 0 8 6 14 0 0 8 10 18

2024 3 1,643 306 306 318 324 3 0 0 8 6 14 0 0 8 10 18

2024 4 1,734 306 306 318 288 3 0 0 8 6 14 0 0 8 10 18

Red text = start of mining, Blue text = mining below water table, Purple text = end mining - pit backfilling production bore no longer accessible, Green text = end mining - no pit backfilling - production bore remains

accessible




The first model stress period was designed to simulate dewatering of Pits 1 and 2, which are the

first to be mined and will be deepened fairly rapidly. The stress period ends at the completion of

Pit 2, when it starts to be backfilled and access to the dewatering bore (PB2) is assumed to be no

longer possible.

The second model stress period was designed to simulate dewatering of Pits 1, 3 and 4, and ends

at the completion of Pit 1, when this pit starts to be backfilled and access to the dewatering bore

(PB1) is assumed to be no longer possible.

The third model stress period was designed to simulate dewatering of Pits 3 and 4, which are the

only pits assumed to remain accessible. Pit 3 is completed 18 months before Pit 4, but water

extraction from the former pit continues in order to provide the 18 L/s needed for mining.

3.2 DEWATERING RATE PREDICTION

The results of the base-case modelling scenario, detailed in Table 5 and shown in Figure 4, indicate that Pits

2 and 1 will need to be dewatered at a rate of about 23 L/s. This is about 5 L/s more than can be used for

mining operations and assumes that pumping commences from the first day of mining. Thereafter, a

dewatering rate of 18-14 L/s is required to allow mining of Pits 1, 3 and 4. The dewatering excess of 5 L/s

will need to be disposed of to the evaporation basin. There is no advantage in starting to dewater Pit 2

before the start of mining as at that time there is no requirement of water for mining operations.

The results of the second, high porosity modelling scenario, detailed in Table 5 and shown in Figure 5,

indicate that dewatering rates of 28-30 L/s will be required during the mining of Pits 1 and 2 and that this

can be reduced to 18 L/s during mining of Pits 3 and 4. The 10-12 L/s of excess dewatering will need to be

disposed of to the evaporation basin.

3.3 WATER LEVEL PREDICTION

Figures 6 and 7 show the water levels that are predicted to occur at the end of the mining for the base-case

and high porosity scenarios, respectively. The water levels are very similar, which is not surprising since

the two models do not vary in terms of permeability.

For the base-case scenario, the modelled drawdown at the end of mining ranges from about 100 m at

Bore 2; through to 10 m, 450 m from the pit margin; to 1 m, 1 km from the pit margin.

For the high-porosity scenario, the modelled drawdown at the end of mining ranges from about 100 m at

Bore 2; through to 10 m, 400 m from the pit margin; to 1 m, 1 km from the pit margin.

The drawdown, in both cases, will not impact any other groundwater users or any groundwater dependent

ecosystems.

4 MODELLING OF EVAPORATION BASIN DISPOSAL CAPACITY

The results of the groundwater flow modelling (above) indicate that dewatering of Pits 1 and 2 will produce

up to 12 L/s of water in excess of what can be used for mining operations. A simple spreadsheet-based

model was therefore constructed to assess the duration over which the evaporation basin can be used to




dispose of 12 L/s (1,037 kL/d). The basin has an area of about 76,200 m2 (Fig. 2) and a maximum fillable

depth of 5.5 m. It will have a HDPE liner to prevent any leakage.

The model was designed to run at a monthly time-step using the rainfall and potential evaporation rates

shown in Table 1. Potential evaporation was discounted by a factor of 0.7 to allow for reduced evaporation

from a large water body, and then by a further 0.9 to allow for reduced evaporation from high-salinity

water.

The results of water balance model, shown in Figure 8, indicate that the proposed evaporation basin will

fill after about 17 months at a disposal rate of 12 L/s. However, the basin will not reach capacity if the

disposal rate is restricted to 5 L/s, as per the base-case modelling scenario.

5 FINAL VOID

No detailed modelling has been conducted to predict the final void water level and salinity. However, by

analogy to other similar, iron-ore pits in the region, such as the Carina Pit mined by MRL in 2011-2016, the

rate of water level recovery is likely to be very slow and stabilise at an elevation that is substantially lower

than that of the regional water table. Salinity will continue to increase as result of evaporation. The pits

will act as groundwater sinks, preventing any flow of highly saline pit lake water into the surrounding

country rocks.

6 SUMMARY AND CONCLUSIONS

Mineral Resources purchased the Parker Range iron-ore deposit from Cazaly Resources in August 2019.

The deposit to be mined as two main pits, with each pit being an amalgamation of two smaller pits. Mining

is scheduled to commence in early 2020, and at a mining rate of 4 Mtpa will be completed by the end of

2024. The two central pits (Pits 1 and 2) will be mined first and then backfilled during the mining of Pits 3

and 4.

The proposed pits vary in depth between about 108 m (Pit 3) and 122 m (Pit 4), which equates to 318 and

288 mRL, respectively. As the standing water level lies at about 362 mRL, the pits will require substantial

dewatering to enable dry-floor mining. Water requirements for mining operations are expected to be

about 18 L/s, so it would be desirable for dewatering to be managed such that it matches the mine water

requirement as closely as possible. An evaporation basin will be constructed to dispose of any excess

dewatering water, should that be necessary.

Drilling data and the results of test-pumping indicate that the Parker Range iron-ore deposit comprises a

narrow, steeply-dipping aquifer of high permeability and porosity enclosed on either side by low-

permeability weathered amphibolite and metasediment.

Two groundwater modelling scenarios were performed to assess the dewatering rates that will be required

during mining. The first, base-case scenario, involved using aquifer parameters which are geologically most

likely. The second, high porosity scenario, involved substantially increasing the specific yield of orebody in

the pit areas, which seems possible.

The results of the base-case modelling scenario indicate that Pits 2 and 1 will need to be dewatered at a

rate of about 23 L/s. Thereafter, a dewatering rate of 18-14 L/s is required to allow mining of Pits 1, 3 and

4. The dewatering excess of 5 L/s will need to be disposed of in the evaporation basin.




The results of the second, high porosity modelling scenario indicate that dewatering rates of 28-30 L/s

would be required during the mining of Pits 1 and 2 and that this might be reduced to 18 L/s during mining

of Pits 3 and 4. The 10-12 L/s of excess dewatering will need to be disposed of to the evaporation basin.

The final radial extent of drawdown is about 1 km from the pit margins. This will not impact any other

groundwater users or any groundwater dependent ecosystems. The southern-most pit (Pit 3) overlaps

water reserve R 13208, but this is not in use and presumably authorisation has been granted to mine (and

dewater) in the area.

The results of a spreadsheet-based water balance model indicate that the proposed evaporation basin will

fill after about 17 months at 12 L/s of water disposal, but will accept all of the excess water for the entire

duration of mining at a disposal rate of 5 L/s.

The pits will act as groundwater sinks after dewatering ceases, preventing any flow of pit lake water into

the surrounding country rocks.

Dated: 22 January 2020 Rockwater Pty Ltd

P de Broekert

Principal Hydrogeologist

REFERENCES

McDonald, M.G., and W.A. Harbaugh, 1988, MODFLOW, A Modular Three-Dimensional Finite-Difference

Ground-Water Flow Model. U.S. Geological Survey, Washington, DC. (A:3980), open file report 83–

875, Chapter A1

Rockwater Pty Ltd, 2009a. Mt Caudan iron ore deposit, results of permeability testing and numerical

modelling of dewatering rates. Unpub. report (361.0/09/02) for Cazaly Resources Ltd, November

2009.

Rockwater Pty Ltd, 2009b. Review of existing groundwater usage, Marvel Loch – Parker Range area.

Unpub. report (361.0/09/01) for Cazaly Resources Ltd, August 2009.

Rockwater Pty Ltd, 2010. Parker Range Project, Mt Caudan iron ore deposit, bore completion, test-

pumping and groundwater modelling report. Unpub. report (361.0/10/01) for Cazaly Resources Ltd,

August 2010.


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mE (MGA)CLIENT: Mineral Resources LtdPROJECT: Parker Range DewateringDATE: November 2019Dwg No: 349.5.1/19/2-1

LOCATION MAPRockwater Pty Ltd

mN (M

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FIGURE 1

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GEOLOGY, BORES AND PROPOSED PITSRockwater Pty Ltd

mN (M

GA)

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FIGURE 2

Pit 1 (306 mRL)

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Pit 3 (318 mRL)

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MODEL BORES AND PERMEABILITY ZONESRockwater Pty Ltd

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FIGURE 3

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1:20,000

FIGURE 6

!C Modelled BoreModelled Water Level (RL)R13208

!C

!C

!C

!C

270

301

281291

311

301311

321

331342

352

360

741000

741000

741500

741500

742000

742000

742500

742500

743000

743000

743500

743500

649650

0

649650

0

649700

0

649700

0

649750

0

649750

0

649800

0

649800

0

649850

0

649850

0

649900

0

649900

0

649950

0

649950

0

650000

0

650000

0

650050

0

650050

0

650100

0

650100

0


HIGH POROSITY SCENARIOMODELLED WATER LEVELEND MINING Rockwater Pty Ltd

mN (M

GA)

1:20,000

FIGURE 7

!C Modelled BoreModelled Water Level (RL)Water Reserve R13208

MODELLING OF PIT DEWATERING AND EVAPORATION BASIN …€¦ · 1 INTRODUCTION Mineral Resources Ltd...

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