GROUNDWATER EVALUATION FOR ANGLO-SAXON ......1900-2013 1 Table 2 : Data from Bores and Wells, Pinjin...

GROUNDWATER EVALUATION

FOR ANGLO-SAXON MINING

PROPOSAL

PINJIN AREA, WA

APRIL 2014

REPORT FOR

HAWTHORN RESOURCES LIMITED

(Report No. 165-0/14/01)

Rockwater Pty Ltd165.0/14/01

TABLE OF CONTENTSPAGE

1 INTRODUCTION 1

2 REGIONAL DESCRIPTION 1

2.1 Climate and Rainfall 1

2.2 Topography and Drainage 1

2.3 Geology 2

2.4 Hydrogeology 2

3 WATER SOURCES FOR HAUL ROAD AND MINING 3

3.1 Bore PSWB001 (‘Tropicana Road Bore’) 4

3.2 REBECCA BORE 4

3.3 BORES ALONG HAWTHORN’S HAUL ROAD 4

3.3.1 Bedrock 43.4 Bedrock Bores Drilled in 2013 6

3.5 Palaeochannel BoreS 7

3.5.1 South of Pinjin 73.5.2 South-East of Rebecca Bore 7

4 GROUNDWATER TENEMENTS AND LICENCES 7

5 CHEMICAL ANALYSIS OF GROUNDWATER 8

6 MODELLED GROUNDWATER INFLOW TO THE PIT 8

6.1 MODEL Description 8

6.2 Model Parameters and Boundary Conditions 9

6.3 Modelling Results 9

6.3.1 Pit Inflows 96.3.2 Sensitivity Analysis 10

7 FINAL VOID ASSESSMENT 11

8 SUMMARY 11

REFERENCES 12

Tables

Table 1 : Mean Monthly and Annual Rainfall for Edjudina Station (BOM Station No. 12027)

1900-2013 1

Table 2 : Data from Bores and Wells, Pinjin Area (1991) 5

Table 3 : Data from Bores and Wells, Edjudina area, 1980-81 5

Table 4 : Results of Groundwater Exploration Programme Pinjin, November 2013 6

Table 5 : Aquifer Parameters Adopted In Model 9

Table 7: Model-Calculated Groundwater Flows 10

Table 8: Results of Sensitivity Analysis 10

Table 9: Pit Void Water Balance 11


TABLE OF CONTENTS(Continued)

Figures

1 Locality Plan with Geology

2 Model Calculated Peak Drawdowns (m) Around Planned Pinjin Pit – A Pit

3 Model Calculated Peak Drawdowns (m) Around Planned Pinjin Pit – A and B Pits

Appendix

I Chemical Analysis of Water Sample from Tropicana Road Bore, by AMDEL

Groundwater Evaluation for Anglo-Saxon Mining ProposalPinjin Area, WA Page 1


1 INTRODUCTION

This groundwater evaluation is concerned with the development of water supplies for the

construction and maintenance of a haul road to transport ore from the proposed Pinjin gold

mine of Hawthorn Resources Limited (‘Hawthorn’) to processing facilities at the Carosue

Dam project of Saracen Mines Limited. The estimated water requirement is 0.4

gigalitres/annum.

A preliminary assessment of mine dewatering for the proposed operation, and a final void

evaluation, are presented herein.

2 REGIONAL DESCRIPTION

2.1 CLIMATE AND RAINFALL

The Pinjin area has a semi-arid climate with very hot summers and mild winters. Average

monthly maxima range from 17oC to 34oC and minima from 5oC to 18oC. Rainfall averages

222 mm per year, with mean monthly values ranging from 10 mm in September to 28 mm in

February (Table 1). The small annual rainfall (on average) is derived variably from low-

pressure systems moving from northerly directions in summer and from southerly directions

in winter. The summer rainfall (January to March) tends to be higher and more variable than

winter rainfall (June to August).

Table 1 : Mean Monthly and Annual Rainfall for Edjudina Station (BOM Station

No.12027) 1900-2013

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

21 28 26 19 22 22 19 17 10 11 14 13 222

Evaporation from a free water surface exceeds 3,000 mm per annum. The large excess of

evaporation over rainfall indicates that groundwater recharge would be limited to the

infrequent intense rainfall events.

2.2 TOPOGRAPHY AND DRAINAGE

The topography at Pinjin is subdued, with ground elevations in the range 325 to 440 m AHD.

Steepest topography occurs along narrow ridges of layered “greenstone” rocks, although flat-

lying sand plain underlain by granitic rocks achieves the highest elevation (about 14 km NW

of Anglo Saxon deposit).

Drainage from the Anglo Saxon area is south-westerly towards Lake Rebecca and north-

easterly towards Lake Raeside (Fig. 1). All the drainage lines are ephemeral. Both lakes are



saline playas that occur along separate palaeodrainages with low gradients to the south-east,

towards the Eucla Basin. The Anglo Saxon deposit, and most of the haul-road route, are in

the Lake Rebecca catchment; the north-eastern part of the haul-road route is in the Lake

Raeside catchment.

2.3 GEOLOGY

A 45 km-wide belt of greenstone rocks extending south-south-easterly through the Edjudina

area is separated by a granite batholith into eastern (Pinjin) and western (Mulgabbie)

segments. The batholith, about 25 km wide, underlies the broad sand plain lying to the west

of the Pinjin greenstones and to the north of Lake Rebecca (Fig. 1).

The Pinjin greenstone belt comprises mainly felsic volcanics, mafic igneous rocks,

metasediments (including thin Banded Iron Formation), and minor ultramafics. It is cut by a

few ENE-trending Proterozoic-age mafic dykes.

Two major northerly-trending shear zones have been interpreted (Swager, 1991); one passes

through the Anglo Saxon deposit, the other is 10 km or more to the west.

A Tertiary-age palaeochannel (fossil drainage channel) of estimated width about 1 km is

located beneath the northern flank of Lake Rebecca, and is thought to run roughly parallel to

the present lake. It has been located by drilling to the south of Pinjin, but is largely undefined.

The palaeochannel contains alluvial deposits, mainly clay and a basal sand bed, to depths of

about 100 m.

2.4 HYDROGEOLOGY

Groundwater occurrence in the Pinjin area may be summarised as follows:

Fresh groundwater (less than 1,000 mg/LTDS) – very rare: small supplies (e.g. bore

LS1 near Relief Hill, Fig. 1) in mafic bedrock.

Stock quality groundwater (less than 6,000 mg/L TDS) – uncommon: small supplies in

bedrock e.g. metasediments, mafics, and granite overburden (e.g. Oldfield well,

Chinamans well).

Highly saline groundwater (generally 40,000 to 200,000 mg/L TDS) – available in

moderate to large supplies near Lake Rebecca in a palaeochannel and in decomposed

bedrock; also found in small to moderate supplies in metasediments, mafics, and

granite overburden.

The lower-salinity groundwater occurs in fractured (permeable) bedrock or overburden in

elevated areas several kilometres from saline playas, at locations where there is opportunity



for recharge from rainfall as a result of the overburden being of small thickness or high

permeability.

High-salinity groundwater is almost ubiquitous, and reaches hypersaline concentrations near

and beneath the playas.

In the vicinity of the Anglo Saxon deposit and along the proposed haul road, the greenstone

and granitic rocks (and overburden) have been found to be low-yielding. Groundwater

supplies located in test holes to date have been mainly in the range 100 to 200 m3/d (1.2 to

2.3 L/s), or less. Permeability values calculated from 11 slug tests on drill holes in the Anglo

Saxon deposit ranged from 0.04 to 2.3 m/d and averaged 0.47 m/d, indicating generally low

permeability of the weathered bedrock at that location. Gravelly material, penetrated by

Rebecca Bore (interpreted to be palaeochannel deposits) near Lake Rebecca, has yielded quite

large water supplies, 400 to 900 m3/d (4.6 to10.4 L/s). A bore along the Tropicana access road

south of the Pinjin mine is also reported to have yielded moderate supplies (about 4 L/s from

possible palaeochannel deposits.

Groundwater levels stand at depths of 35 to 50 m below ground surface (bgs) in the elevated

bedrock areas, and at very shallow depths, probably 0 to 2 m bgs, at Lake Rebecca. The

relative groundwater levels slope down from 339 m AHD near Anglo Saxon to about 325 m

AHD at Lake Rebecca, reflecting groundwater flow southwards towards the lake. The same

would occur north-eastwards from near Anglo Saxon towards Lake Raeside. When the lakes

become inundated, saline groundwater would flow away from the lakes, in peripheral areas.

3 WATER SOURCES FOR HAUL ROAD AND MINING

The water-supply requirements for constructing and maintaining the 50 km proposed haul

road for the Anglo Saxon project are estimated to be 12.5 L/s (1,100 m3/d), based on an

average usage of 0.25 L/s per km. The water might be drawn from existing bores (owned by

others) adjacent to the project’s mining and miscellaneous tenements, and from new bores

(yet to be constructed) along the haul-road route. The owners of the existing adjacent bores –

AngloGold Ashanti Australia Limited (Tropicana project) to the east and Saracen Mineral

Holdings Limited (Carosue Dam project) to the west – have entered into discussions that may

result in Hawthorn Resources having access to water from the nominated bores: PSWB001

and Rebecca Bore respectively.



3.1 BORE PSWB001 (‘TROPICANA ROAD BORE’)

The details of Bore PSWB001 are as follows:

Coordinates (MGA): 470,060mE 6,666,470mN

Depth: 100 m

Casing Diameter: 155mm

Casing material: PVC Class 12

Slotted Intervals: 24.5m – 78.5m and 90.5 – 96.5m

Static Water Level: 4m

Water Salinity: 91,300 mg/L TDS

Bore PSWB001 is not currently equipped for use by AngloGold. The pumping rate of 4L/s

(350 m3/d) has been assigned to this bore, subject to confirmation by formal test-pumping.

Higher pumping rates might be sustainable.

3.2 REBECCA BORE

The details of Rebecca Bore are as follows:

Coordinates: 438,435mN 6,682,643mE

Depth: 81m

Casing Diameter: 155mm

Casing Material: PVC Class 12

Slotted Interval: 3-81m

Static Water Level: 23.3m

Rebecca Bore is reported to have yielded 10 L/s when it was newly-constructed in 2003. It

has been pumped for several years, and in 2012-13 it was pumped at average rates in the

range 1.2 to 4.6 L/s for road-watering use by Saracen Holdings. These rates are taken to be

less than the bore’s capacity. Subject to agreement and confirmation by test-pumping, the

pumping rates for Hawthorn’s use could be in the range 3 to 5 L/s. Higher rates might be

sustainable, depending on bore performance and Saracen’s water usage.

3.3 BORES ALONG HAWTHORN’S HAUL ROAD

3.3.1 Bedrock

Groundwater produced from bedrock at rates of 100 m3/d (0.9 L/s) or more are likely to be

useful if located within two or three kilometres of the haul road route. Bore depths will need

to be up to 100 m, as static water levels are 30 to 50 m below ground surface (m bgs) in the



moderately-elevated areas in the vicinity of the haul road. In low-lying areas near the salt

lakes, the water levels are less than 10 m bgs (e.g. at Ten Mile Well).

The existing bedrock bores and wells in the Pinjin area, listed in Table 2 from the 1991

Rockwater report, are reported to have provided small supplies (up to 30 m3/d) of brackish

water. They appear to have been constructed to only a few metres below static water level and

therefore tap the lowest-salinity groundwater. Deeper bores would be expected to produce

larger supplies of higher-salinity water. Generally the rock types were sheared (schistose) acid

and mafic volcanic rocks, and metasediments.

Table 2 : Data from Bores and Wells, Pinjin Area (1991)

Name Bore or

Well

Depth

m

SWL

m

Salinity

mg/L TDS

Supply

cu m/d

Rock Type

Oldfield W 55 49 4,100 11 schist/ acid volcanic

Bests B ND* ND “good” “small” schist/ acid volcanic

Battery W 49? ND “salty” 27? schist/ basic volcanic

Airstrip W ND 30 4,900 “small” schist/metasediments

Kurrajong W 18 ND 11,000 ND alluvium and granite

Ten Mile W ND 8 8,500 30 alluvium and metasediments

Table 3 contains data from an assessment of the Edjudina area, directly north of Pinjin, in

1980. It is seen that the groundwater salinities range from 670 to 34,000 mg/L TDS in the

nominated bores and wells, which are all located south of the latitude of the Edjudina

homestead. The data show that although there is a wide range of salinities, locally there is

fresh and brackish groundwater that suffices for stock-watering.

Table 3 : Data from Bores and Wells, Edjudina area, 1980-81

Name Bore or Well Water Salinity

mg/L TDS

Monaghan B 3,070

Xmas B 8,800

Kingsley W 7,060

Windy W 670

Byer W 980

Bore Well B 4,700

Soapy Head W 4,050

Loafer W 2,120

Homestead South B 1,350

Station W 1,600

West B 1,070

Lake W 2,190

PW 23A* B 3,000

PW 24C* B 34,000

PW 25* B 1,250

* Located in the Soapy Head – Bore Well area



3.4 BEDROCK BORES DRILLED IN 2013

Five recently-drilled groundwater exploration holes drilled in the vicinity of the haul road

route gave results that suggested useful supplies (1 to 2 L/s or more per bore) might be

available from production bores at those sites. Larger-diameter holes/bores (drilled at 216 mm

diam.) are likely to provide larger supplies than the 108 mm diam. test holes, although this

would need to be confirmed by test-pumping. A summary of data from the productive

exploration holes is provided in Table 3, and locations are shown in Figure 1.

Table 4 : Results of Groundwater Exploration Programme Pinjin, November 2013

Hole IDMGAmE

MGAmN

DrillDepth(m bgl)

WaterIntersected

(m bgl)

MaxAirlift

Yield (L/s)

Salinity(mg/LTDS)

pHAquifer

Lithology

HWB002 467560 6677630 89 42 2 5,400 7.57 Meta Basalt

HWB003 469264 6679109 93 54 0.9 14,500 8.1 Meta Basaltand BIF

HWB005 468927 6680528 87 52 1-2 34,000 7.59 BIF

HWB010 452693 6681814 74 41 1.8 20,200 7.6 Granite

HWB012 477610 6668978 78 33 0.7 8,100 6.97 Dolerite

One of these test-drilling sites (HWB002) is near Oldfield Well and therefore is probably

limited to Station use.

HWB003 intersected 10 m of BIF at about 54 m depth, and gave an air-lift of 0.9 L/s of

14,500 mg/L TDS water; this location is near a mapped strata-displacement.

HWB005 targeted fractured BIF, which it intersected from 35 to 87 m depth, and yielded 1 to

2 L/s of 35,000 mg/L TDS water.

HWB010, in granite country 4.3 km west of Chinamans Well, gave a maximum airlift yield of

1.8 L/s of 20,200 mg/L TDS water from 67 m depth, although the rate seems to have reduced

to 0.5 L/s at 72 m depth.

While the actual productivity of bores at these locations is not known at this stage, an

individual bore supply of 2 L/s equates to 172 kL/d which would be pumped to storage in a

lined turkey-nest dam, and (based on similar operations) should be sufficient to maintain 8 km

of road.

Additional test-drilling sites have been selected along the haul-road route. There are presently

estimated to be an additional prospective site in BIF strata on Pinjin station and five or more

potential sites (to be confirmed by ground magnetics) underlain by granitic rock along the

WNW-trending haul-road segment on Edjudina Station.



Two of the groundwater test holes drilled in 2013 near the haul-road route yielded between 1

and 2 L/s and have potential to supply more than 2 L/s each when production bores are

constructed at larger diameter (152 mm). It is realistic that a total of five water bores could be

constructed along the haul-road route, at successful exploration-hole sites.

3.5 PALAEOCHANNEL BORES

3.5.1 South of Pinjin

The position of the palaeochannel would best be determined using a gravity survey for about

5 km along the Kurnalpi–Pinjin road where it crosses Lake Rebecca (Line A-A’, Fig. 1). Sites

for drilling test hole(s) and then constructing a bore to about 90 m depth would be selected

from the gravity data.

A groundwater exploration hole would be drilled at about 152 mm diameter using mud-rotary

method. If sand with aquifer potential is encountered, the hole would be reamed out to

254 mm diameter, lined with 155 mm PVC casing and stainless-steel screens, and sand-

packed in the annulus. The completed bore would be air-lift developed and test-pumped.

It should be noted that the palaeochannel sand aquifer is likely to provide a larger and longer-

lasting supply than the bedrock option, but the water will be considerably more saline and

may not be as conveniently located.

3.5.2 South-East of Rebecca Bore

Given that the aquifer supplying Rebecca bore is described as palaeochannel sand, it most

likely extends south-easterly in a channel parallel to the Lake Rebecca playa. Subject to a

tenement being established, a gravity survey would be conducted (Line B-B’, Fig. 1) to locate

the channel, and test-drilling plus bore construction carried out as for item 2.5.1 above.

4 GROUNDWATER TENEMENTS AND LICENCES

The current 26D licence to construct water bores, from the Department of Water (DoW),

applies to mineral tenements E 31/782, E 31/882, and E 31/1049. Groundwater exploration

drilling on Edjudina Station is being conducted with the permission of the landholder.

Miscellaneous Licences along the haul-road route have been applied-for. It is proposed that

new Miscellaneous Licences be applied-for in areas south-east of Rebecca Bore and south of

Anglo Saxon mine (Fig. 1) for the test-drilling of potential palaeochannel sites.



5 CHEMICAL ANALYSIS OF GROUNDWATER

Most of the water used for dust-suppression will be hypersaline, being sourced from

Tropicana Road Bore or Rebecca Bore. An analysis of a water sample taken in August 2013

from Tropicana Road Bore, made available by AngloGold Ashanti, is presented in

Appendix I. The sample represents groundwater from palaeochannel strata on the eastern side

of Lake Rebecca. Groundwater from Rebecca Bore is likely to be similar, and will be

analysed in due course.

The analysis of the Tropicana Road Bore water, by AMDEL, indicates a salinity of 91,000 to

93,000 mg/L TDS i.e. about 2.6 times the salinity of sea water. The water contains a relatively

high proportion of magnesium (relative to calcium) compared to sea water, reflecting the

magnesium-rich bedrock and overburden locally. From the analysis, the water appears to

contain no constituents in concentrations that would be detrimental to its use for dust-

suppression. Because of the high water-salinity, preventative measures will need to be

undertaken to restrict surface run-off of saline water into vegetation or drainage lines.

6 MODELLED GROUNDWATER INFLOW TO THE PIT

6.1 MODEL DESCRIPTION

The numerical model constructed to represent the proposed enlarged Anglo Saxon pit consists

of a rectangular grid of 78 columns, 36 rows, and one active layer, covering an area of 2.5 km

east-west by 4.6 km north-south, centred on the Anglo-Saxon deposit. Cell sizes range from a

minimum of 20 m by 20 m at the planned pit to 100 m by 100 m over much of the model area

and 100 m by 500 m near the peripheries of the model area. It utilises Processing Modflow

Pro version 8.0.39 (Simcore Software, 2013) that incorporates Modflow, the finite-difference

groundwater modelling software designed by the US Geological Survey (McDonald and

Harbaugh, 1988).

The water table was assumed to be flat at 338 m AHD, and it is assumed that there are

permeable rocks extending down to 285 m AHD, the base of the model. The crest of the pit is

at an elevation of about 385 m AHD, and mining is planned to extend to between about 335

and 325 m AHD, in the northern and central pit areas (A pit), and to 322 m AHD in the south

(B pit). The required amount of drawdown is therefore small, ranging from a minimum of

about 3 m in the northern pit area, 13 m in the central pit area, and to a maximum of about

16 m in the southern pit area.

Modflow’s Drain package was used to represent in-pit sumps (and/or any dewatering bores).



6.2 MODEL PARAMETERS AND BOUNDARY CONDITIONS

Hydraulic conductivity was set at 0.08 m/d (horizontal and vertical) and increased to 0.16 m/d

along strike of the pit. This value is the geometric mean of the permeability values (0.04 to

2.3 m/d) obtained from falling head permeability tests (slug tests) on drill holes in the Anglo

Saxon deposit.

No geological structures of locally high or low permeabilities have been included in the

model, and all the rock material is assumed to have hydraulic properties in the ranges noted in

Table 5. An east-west fault that intersects the southern portion of pit A was not included

because the permeability of the faulted rock is unknown and the fault intersects only a small

portion of the required dewatering zone.

There were no pumping-out test-data available for calibration of the model. Instead, the

parameter values were varied within their likely ranges, as part of the sensitivity analysis.

Recharge was assumed to be negligible and excluded in running the model as it will be low,

perhaps one per cent of average rainfall, i.e. 2.2 mm/year.

The model boundaries have been set as a constant-head type.

Table 5 : Aquifer Parameters Adopted In Model

Parameter Units Adopted Value

Hydraulic Conductivity

(horizontal & vertical)m/d 0.08 to 0.16

Specific Yield 0.05

6.3 MODELLING RESULTS

6.3.1 Pit Inflows

The model was run to simulate dewatering of pits A and B for the periods when mining

extends below the water table. Pits A and B are planned to be mined consecutively, for

durations of 12 months per pit. Mining is scheduled to intersect the water table not until the

final three months of mining in each pit when lowering of the water table by 13 m (A pit,

central area) and 16 m (B pit) will be required. Drain conductance (which simulates

dewatering) remains active for the mining period 12 to 21 months; however, in reality the

dewatering operations might not be required during this period if the northern and southern

pits are completed separately.

Model-calculated groundwater flows to pit drains/sumps are given in Table 7. They indicate

that pit inflows are moderately low, with highest average flow of about 5.8 L/s (500 m3/d).



Table 6: Model-Calculated Groundwater Flows

Months Av. Flows

(L/s)

9 to 12 5.2

12 to 21 2.4

21 to 24 5.8

Model-calculated (peak) drawdowns around pit A at the end of 12 months of mining and 3

months of dewatering are shown in Figure 2. Figure 3 shows the model-calculated

drawdowns at the completion of mining of both pits; measurable drawdowns are predicted to

extend up to 285 m north and 145 m south of the planned pit-perimeter, and about 220 m to

the west and 180 m to the east.

6.3.2 Sensitivity Analysis

Model parameters were varied in turn to determine their effect on the calculated total volumes

of groundwater to be pumped during dewatering. The sensitivity analyses results are given in

Table 8 in the form of percentages of the flows calculated for the adopted model.

Table 7: Results of Sensitivity Analysis

Parameter, and Variation% of Adopted Model

Flows

Horizontal conductivity *2 160

Horizontal conductivity *0.5 64

With barrier boundaries 100

With east-west fault 110

Specific yield *2 127

Specific yield *0.5 81

With 1% recharge 101

The results indicate that the model is sensitive to horizontal conductivity, and to a lesser

degree specific yield; and it is insensitive to the nature of the model boundaries and recharge.

Hydraulic conductivity values, which were obtained from the falling-head permeability tests,

could be more-accurately assessed by conducting pumping tests if a bore or bores were to be

constructed. Values of specific yield can only be determined after the aquifer has been

stressed for an extended period, allowing calculations based on the volume of the drawdown

cone and the total volume of water that was pumped. Consequently, there is a moderately

high probability that actual pit inflow rates could be double or half those calculated; only

minor inflows of about 1 L/s would be expected if actual permeability is in the lower range

(0.01 to 0.04 m/d) of the hydraulic conductivities obtained from the falling-head permeability

tests.



7 FINAL VOID ASSESSMENT

The numerical groundwater model was used with a water balance to assess the nature of the

final pit void.

Groundwater inflows to the mined-out pit at several pit water levels were estimated using the

model. These are included in the water balance given in Table 9.

Table 8: Pit Void Water Balance

In-Pit WaterLevel

Water Area Inflows Rainfall Evap. Balance

(m AHD) (m2) (m3/d)

375 97055 0 47.2 566 -519

335 12168 37 5.9 71 -28

330 4672 92 2.3 27 67

325 925 139 0.5 5 134

322 300 164 0.1 2 162

The values in the last column “Balance” are groundwater inflows plus rainfall accumulation

minus evaporative losses.

The rainfall accumulation value is taken to be 80 percent of the average annual rainfall within

the planned pit perimeter, on a daily basis. Evaporation losses are taken to be the average

dam evaporation rate (Luke, Burke and O’Brien, 1988) over the area of open water for each

pit water level.

It can be seen from Table 9 that inputs and outputs are in balance when the pit water level is

at about 333.5 m AHD, compared to an initial water level of about 338 m AHD.

The small final pit void has very high probability, therefore, of being a permanent

groundwater sink. The salinity of water in the void will gradually increase, but this will have

no impact on the surrounding groundwater as there will be no flow from the void.

8 SUMMARY

Water-supply requirements for the proposed gold-mining operation by Hawthorn Resources at

Pinjin are estimated to be 1,100 m3/d (0.4 gigalitres/annum), almost all of it to be used for

haul-road dust-suppression. Local groundwater will provide the supplies. Subject to

arrangements with adjacent project-operators, the water will be obtained from the Tropicana

Road Bore or Saracen’s Rebecca Bore. These bores produce hypersaline water from

palaeochannel aquifers. Alternatively or additionally, several small-producing bores could be



constructed along the haul-road route at locations where groundwater exploration drilling and

geophysical surveys have indicated potentially useful supplies.

The water produced from the palaeochannel aquifers will be hypersaline: for example, about

92,000 mg/L TDS from Tropicana Road Bore. As for other projects in the Eastern Goldfields,

water containment procedures will be designed to prevent incursion of saline water into local

catchments that may be non-saline.

Pit dewatering at between 250 and 1,000 m3/d (3 and 12 L/s) is the estimated range of

maximum pumping rates to lower water levels 13 to 16 m at the final mining depths. The

estimates are based on numerical modelling and sensitivity analysis incorporating some site-

measured permeability values. For most of the mining period, dewatering will be not required,

or it will be at lower rates than those noted.

The final mine void is calculated to become a groundwater sink, with a water level of about

333.5 m AHD, i.e. about 4.5 m lower than the present groundwater level.

Dated: 14 April 2014 Rockwater Pty Ltd

Claire Kasperkiewicz J R Passmore

Senior Hydrogeologist Principal

REFERENCES

Luke, G.J., Burke, K.L., and O'Brien, T.M., 1988, Evaporation data for Western Australia.

Tech. Report No. 65 (2nd Ed), W.A. Dept. of Agriculture.

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.

Simcore Software, 2013, Processing Modflow, An integrated modeling environment for the

simulation of groundwater flow, transport, and reactive processes.

Swager, C.P., 1994, Geology of the Pinjin 1:100 000 sheet: Western Australia Geological

Survey, 1:100 000 Geological Series Explanatory Notes, 22p.


FIGURES

CLIENT:

PROJECT:

DATE:

Dwg. No:

LOCALITY PLANWITH GEOLOGY

Figure 1

165-0/Surfer/Rpt 14-01/100k Geology.srf

Hawthorn Resources Limited

Pinjin Project

April 2014

165-0/14/4-1

G 3100004L 3100032

L 3100066

M 3100078

M 3100079

M 3100088

M 3100113

M 3100284

Tropicana Road Bore

Deenya Bore

Rebecca Bore

Chinaman's Well

PW 40

PW 41

PW 41A

PW 42PW 43PW 44

HWB002

HWB003

HWB005

HWB010

HWB012

LS1

436000 440000 444000 448000 452000 456000 460000 464000 468000 472000 476000 480000

Easting (m MGA Zn 51)

6656000

6660000

6664000

6668000

6672000

6676000

6680000

6684000

6688000

6692000

Nort

hin

g(m

MG

AZ

n51)

LEGEND

Test Hole (2013)

Existing Bore or Well

WIN Database Test Hole

Suggested Miscellaneous Licence

Proposed Haul Road

Boundary of Current MiscellaneousLicence (application) & MiningTenements

Proposed Line of Gravity Survey

RELIEF HILL

A

A'

B

B'

B

B'

CLIENT:

PROJECT:

DATE:

Dwg. No:


Pinjin Project

April 2014

165-0/14/01-2

MODEL-CALCULATED PEAK DRAWDOWNS (m)

AROUND PLANNED PINJIN PIT

A PIT

Figure 2

I/165-1/surfer/14-01/Peak Drawdowns - A Pit.srf

BUSSELL HWY

SUES RD

WONNERUP SOUTH RD1

35

79

11

66

72

00

06

67

22

00

66

72

40

06

67

26

00

66

72

80

06

67

30

00

66

73

20

0

mN

MG

A

473600 473800 474000 474200 474400 474600

mE MGA

3Modelled peak drawdown (m)after 12 months of mining / 3 months of dewatering A Pit

Pit outline

Area to be dewatered

A Pit - planned

B Pit - planned

CLIENT:

PROJECT:

DATE:

Dwg. No:


Pinjin Project

April 2014

165-0/14/01-3

MODEL-CALCULATED PEAK DRAWDOWNS (m)

AROUND PLANNED PINJIN PIT

A and B PITS

Figure 3

I/165-1/surfer/14-01/Peak Drawdowns - A & B Pits.srf

BUSSELL HWY

SUES RD

WONNERUP SOUTH RD

1

1

1

1

3

3

3

5

5

5

7

7

9

9

11

111

31

5

66

72

00

06

67

22

00

66

72

40

06

67

26

00

66

72

80

06

67

30

00

66

73

20

0

mN

MG

A

473600 473800 474000 474200 474400 474600

mE MGA

3Modelled peak drawdown (m)after 24 months of mining / 3 months of dewatering of B Pit & A Pit

Pit outline

Area to be dewatered

A Pit - planned

B Pit - planned


APPENDIX I

Chemical Analysis of Water Sample

from Tropicana Road Bore, by Amdel

Provided by Anglogold Ashanti Australia Limited

GROUNDWATER EVALUATION FOR ANGLO-SAXON ......1900-2013 1 Table 2 : Data from Bores and Wells, Pinjin...

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