Prepared by:

ENVIRONMENTAL GEOCHEMISTRY INTERNATIONAL

PTY LTD

81A College Street, Balmain, NSW 2041 Australia

Telephone: (61-2) 9810 8100 Facsimile: (61-2) 9810 5542

Email: [email protected]

ACN 600 298 271 ABN 48 600 298 271

For:

NITRO SOLUTIONS PTY LTD

ON BEHALF OF KGL RESOURCES PTY LTD

September 2018

Document No. 9350/1273

Geochemical Assessment of the Jervois Base Metal Project, Northern Territory

ii

Environmental Geochemistry International Pty Ltd

Contents

LIST OF TABLES ................................................................................................................................ iii

LIST OF FIGURES .............................................................................................................................. iii

LIST OF PLATES ................................................................................................................................ iv

LIST OF APPENDICES ........................................................................................................................ v

LIST OF ABBREVIATIONS ................................................................................................................ vi

EXECUTIVE SUMMARY ................................................................................................................... viii

1.0 INTRODUCTION ........................................................................................................................ 1

2.0 BACKGROUND AND GEOLOGY ............................................................................................. 1

4.0 SAMPLE SELECTION AND PREPARATION ......................................................................... 16 4.1 Drill Hole Samples for Future Waste Rock and Ore .............................................................. 16 4.2 Historic Mine Materials .......................................................................................................... 27 4.3 Metallurgy Samples ............................................................................................................... 27

5.0 METHODOLOGY ..................................................................................................................... 28

6.0 GEOCHEMICAL CHARACTERISATION RESULTS FOR WASTE ROCK AND ORE

SAMPLES ........................................................................................................................................... 29 6.1 pH and EC ............................................................................................................................. 29 6.2 Acid Base (NAPP) Results .................................................................................................... 30 6.3 Single Addition NAG Results ................................................................................................. 35 6.4 Sequential NAG Testing ........................................................................................................ 38

6.5 Kinetic NAG Testing .............................................................................................................. 38 6.6 Acid Buffering Characteristic Curve (ABCC) Testing ............................................................ 39 6.7 Carbon Speciation Testing .................................................................................................... 40 6.8 Sulphur Speciation ................................................................................................................. 43 6.9 Multi-Element Analysis of Solids ............................................................................................ 45 6.10 Composition of Water Extracts .............................................................................................. 46 6.11 Sample Classification and Distribution of Geochemical Rock Types .................................... 46

7.0 GEOCHEMICAL CHARACTERISATION RESULTS FOR SAMPLES OF HISTORIC MINE

MATERIALS ........................................................................................................................................ 50

8.0 GEOCHEMICAL CHARACTERISATION RESULTS FOR METALLURGICAL ORE FEED

AND TAILINGS SAMPLES ................................................................................................................ 53

9.0 CONCLUSIONS AND RECOMMENDATIONS ........................................................................ 56

iii


List of Tables

Table 1: Relative abundance of alteration and lithological combinations for Rockface Underground

waste rock and ore. .......................................................................................................... 17

Table 2: Count of selected samples by alteration and lithological combinations for Rockface

Underground waste rock and ore. .................................................................................... 17

Table 3: Relative abundance of alteration and lithological combinations for Marshall/Reward

Underground waste rock and ore. .................................................................................... 18

Table 4: Count of selected samples by alteration and lithological combinations for

Marshall/Reward Underground waste rock and ore. ........................................................ 18

Table 5: Relative abundance of alteration and lithological combinations for Marshall/Reward Open

Cut waste rock and ore. .................................................................................................... 19

Table 6: Count of selected samples by alteration and lithological combinations for

Marshall/Reward Open Cut waste rock and ore. .............................................................. 20

List of Figures

Figure 1: Box plots showing the distribution of S, Ca and Mg for Rockface Underground split by

alteration domain. Box plots have 5th, 10th, 25th, 50th (median), 75th, 90th and 95th

percentiles, and mean marked. ........................................................................................ 21

Figure 2: Box plots showing the distribution of S, Ca and Mg for Marshal/Reward Underground split

by alteration domain. Box plots have 5th, 10th, 25th, 50th (median), 75th, 90th and 95th


Figure 3: Box plots showing the distribution of S, Ca and Mg for Marshal/Reward Open Pit split by

alteration domain. Box plots have 5th, 10th, 25th, 50th (median), 75th, 90th and 95th


Figure 4: Plots showing the range of S, Ca and Mg values (minimum, median and maximum)

represented by the samples selected for Rockface Underground split by alteration

domain. ............................................................................................................................. 24


represented by the samples selected for Marshall/Reward Underground split by alteration

domain. ............................................................................................................................. 25


represented by the samples selected for Marshall/Reward Open Pit split by alteration

domain. ............................................................................................................................. 26

Figure 7: Plot showing pH1:2 and EC1:2 versus total S for waste rock samples. ........................... 30

Figure 8: Box plot showing the distribution of S split by rock unit. Box plots have 5th, 10th, 25th,

50th (median), 75th, 90th and 95th percentiles, and mean marked. ................................ 32

Figure 9: Box plot showing the distribution of ANC split by rock unit. Box plots have 5th, 10th, 25th,

50th (median), 75th, 90th and 95th percentiles, and mean marked. ................................ 32

Figure 10: Acid-base account (ABA) plot split by waste rock unit. .................................................... 33

Figure 11: As for Figure 10 with expanded axes. .............................................................................. 33

Figure 12: Acid-base account (ABA) plot for ore split by oxidation. .................................................. 34


iv


Figure 14: ARD classification plot showing NAGpH versus NAPP, split by waste rock unit. ............ 36

Figure 15: As for Figure 8 with an expanded NAPP axis. .................................................................. 36

Figure 16: ARD classification plot for ore samples showing NAGpH versus NAPP, split by oxidation.

37

Figure 17: As for Figure 8 with an expanded NAPP axis. .................................................................. 37

Figure 18: Total C versus carbonate C. ............................................................................................. 41

Figure 19: ANC estimated from Total C versus standard ANC by titration. ....................................... 41


Figure 21: ANC estimated from Total C and standard ANC by titration versus effective ANC from

ABCC testing. ................................................................................................................... 42


Figure 23: ICP S versus Leco total S for waste rock and ore samples. ............................................ 44


Figure 25: Stacked bar chart showing proportions (by sample count) of ARD classes for each major

rock type. .......................................................................................................................... 47

Figure 26: Box plot showing the distribution of S split by ARD classification for waste rock and ore

samples. Box plots have 5th, 10th, 25th, 50th (median), 75th, 90th and 95th percentiles.

48

Figure 27: Box plot showing the distribution of NAPP (ANC Total C) split by ARD classification for

waste rock and ore samples. Box plots have 5th, 10th, 25th, 50th (median), 75th, 90th

and 95th percentiles marked. ........................................................................................... 48

Figure 28: Box plot showing the distribution of NAGpH split by ARD classification for waste rock and

ore samples. Box plots have 5th, 10th, 25th, 50th (median), 75th, 90th and 95th

percentiles marked. .......................................................................................................... 49

Figure 29: Acid-base account (ABA) plot for historic mine material samples. ................................... 50

Figure 30: ARD classification plot showing NAGpH versus NAPP for historic mine material samples.

51

Figure 31: Acid-base account (ABA) plot for metallurgical samples. ................................................. 54

Figure 32: ARD classification plot showing NAGpH versus NAPP for metallurgical samples. .......... 55

List of Plates

Plate 1: Bellbird Pit showing shallow workings, dumps of stockpiled oxide copper ore, and side

cast waste rock mullock heaps. .......................................................................................... 3

Plate 2: Bellbird Pit showing shallow workings, dumps of stockpiled oxide copper ore, and side

cast waste rock mullock heaps. .......................................................................................... 3

Plate 3: Bellbird Pit showing shallow workings and side cast waste rock mullock heaps. .............. 4

Plate 4: Green Parrot Pit. ................................................................................................................. 4

Plate 5: Green Parrot TSF. .............................................................................................................. 5

Plate 6: Tailings or milled ore storage adjacent to Green Parrot process plant. ............................. 5

Plate 7: Green Parrot ROM pad, stockpiled ore, process plant, and tailings/milled ore storage. .... 6

Plate 8: Stockpiled ore from Green Parrot. ...................................................................................... 6

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Plate 9: Surface salts due to partial sulphide oxidation on northern part of Bellbird Pit

development. ...................................................................................................................... 7

Plate 10: Surface salts due to partial sulphide oxidation on northern part of Bellbird Pit

development. ...................................................................................................................... 7

Plate 11: Galena-sphalerite ore with white salts and oxide copper ore. ............................................ 8

Plate 12: Galena-sphalerite ore with green-yellow salts. ................................................................... 8

Plate 13: Mineralised zone with abundant chalcopyrite and pyrite. Dark phases are mainly

magnetite. Hole KJD216, 640.65m. .................................................................................. 10

Plate 14: Mineralised zone with massive sulphide dominated by pyrite with lesser chalcopyrite.

Hole KJD215, 613.25m. .................................................................................................... 10

Plate 15: Mineralised zone with massive sulphide dominated by chalcopyrite with lesser pyrite.

Hole KJD216, 645.85m. .................................................................................................... 11

Plate 16: Mineralised zone with abundant chalcopyrite and pyrite, and with carbonate veining. Dark

phases are mainly magnetite. Hole KJD216, 641.90m. ................................................... 11

Plate 17: Sharp contact between the mineralised zone and non-sulphidic waste rock. Hole

KJD216, 647.27m to 650.83m. ......................................................................................... 11

Plate 18: Typical non-sulphidic pelite waste rock in the distal alteration zone. Hole KJD216, 688.48

to 691.86m. ....................................................................................................................... 12

Plate 19: Typical non-sulphidic psammite waste rock in the distal alteration zone. Hole KJD216,

664.39 to 667.73m. ........................................................................................................... 12

Plate 20: Minor pyrite on foliations in distal alteration zone. Hole KJD216, 571.15m. .................... 12

Plate 21: Minor pyrite associated with quartz vein in distal alteration zone. Hole KJD216, 568.00m.

13

Plate 22: Pyrite on foliations and disseminated pyrite in intermediate alteration zone. Hole KJD216,

580.2m. ............................................................................................................................. 13

Plate 23: Disseminated pyrite in intermediate alteration zone. Hole KJD216, 581.5m. .................. 14

Plate 24: Pyrite on foliations and disseminated pyrite in intermediate alteration zone. Hole KJD216,

583.4m. ............................................................................................................................. 14

Plate 25: Waste proximal alteration zone with massive magnetite and significant pyrite and

chalcopyrite. Hole KJD215, 610.0m. ................................................................................ 14

Plate 26: Typical thin carbonate veining in distal alteration zone. Hole KJD216, 557.5m. .............. 15

Plate 27: Larger carbonate veining in ore zone. KJD212, 687.3m. ................................................. 15

Plate 28: Carbonate breccia in proximal alteration zone. KJD215, 595.65m. ................................. 15

List of Appendices (after text)

Appendix A – Assessment of Acid Forming Characteristics

Appendix B – Acid Forming Characteristics and Multi-Element Testing Tables

Appendix C – Kinetic NAG and ABCC Plots

vi


List of Abbreviations

Abbreviations Used in Geochemical Assessment

ARD Acid Rock Drainage

AMD Acid, Metalliferous and Saline Drainage

NMD Neutral and Metalliferous Drainage

ABA Acid Base Account

pH1:2 pH of a sample slurry with a solid to water ratio of 1:2 (by weight)

EC1:2 Electrical Conductivity of a sample slurry with a solid to water ratio of 1:2 (by weight)

ESP Exchangeable Sodium Percentage

ECEC Effective Cation Exchange Capacity

S Sulphur

CRS Chromium Reducible Sulphur

KCl Potassium Chloride

H2SO4 Sulphuric Acid

SO4 Sulphate

CaCO3 Calcium Carbonate

ANC Acid Neutralising Capacity in kg H2SO4/t

ANCABCC Acid Neutralising Capacity in kg H2SO4/t estimated from ABCC testing

CNV Carbonate Neutralising Value in kg H2SO4/t

MPA Maximum Potential Acidity, calculated from total S in kg H2SO4/t

NAPP Net Acid Producing Potential, calculated from ANC and total S (or MPA) in

kg H2SO4/t.

NAG Net Acid Generation (test)

NAGpH pH of NAG solution before titration

NAG(pH4.5) NAG acidity titrated to pH 4.5 in kg H2SO4/t

NAG(pH7.0) NAG acidity titrated to pH 7.0 in kg H2SO4/t

ABCC Acid Buffering Characteristic Curve

GAI Geochemical Abundance Index based on multi-elements of solids

PAF Potentially Acid Forming

PAF-LC Potentially Acid Forming - Low Capacity

NAF Non Acid Forming

UC Uncertain

AC Acid Consuming

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Units of Measurement

% Percentage

°C Degrees Celsius

dS Deci Siemen

µm Micrometre

mm Millimetre

m Metre

mg Milligram

g Gram

mg Milligram

kg Kilogram

t Tonne

L Litre

ml Millilitre

Other Abbreviations

ALS Australian Laboratory Services

EGi Environmental Geochemistry International Pty Ltd

ROM Run-of-Mine

viii


Executive Summary Environmental Geochemistry International Pty Ltd (EGi) was commissioned by Nitro Solutions Pty

Ltd on behalf of KGL Resources Pty Ltd (KGL) to carry out a geochemical assessment of the Jervois

Base Metal Project (the Project), located approximately 270 km east-north-east of Alice Springs,

Northern Territory. This work will contribute to an Environmental Impact Statement (EIS) for the

Project. The objectives of the geochemical assessment were to identify issues and opportunities, and

clarify implications for materials handling, storage and construction considerations.

The Project would be developed to extract copper, lead and zinc ore from a variety of individual

deposits, using both underground and open cut mining methods, and will generate waste rock

dumps, low grade ore and ore stockpiles, tailings storage facilities, open cut pits and underground

workings. There have been historic mining disturbances on site, including tailings storage facilities,

waste rock dumps, decommissioned processing plants and equipment, pits, prospecting trenches,

run of mine (ROM) pads, water storages and evaporation ponds, an exploration camp, exploration

disturbances, roads and tracks. Where possible, the project would utilise the historic infrastructure to

minimise the footprint impact.

The project area is arid with dry, hot summers and short, dry winters. Mean annual rainfall is

approximately 300mm, mainly falling between October and March, and sometimes in high intensity

events that cause flooding.

The following samples were tested:

• 662 waste rock and ore samples from Rockface and Marshall/Reward Deposits to represent

the geological and spatial variation of mine materials;

• 22 historic mine material samples to provide some initial guide to potential legacy

geochemistry issues; and

• 20 ore feed and tailings samples from metallurgical test work carried out on ore from

Rockface, Marshall/Reward, Green Parrot and Bellbird deposits to represent the range of ore

and tailings materials likely to be produced.

Results show that the Project open cut and underground mine waste rock materials will comprise

mainly NAF material, accounting for 70% of the waste rock samples tested. Note that this proportion

does not reflect the true proportion of materials to be mined, and the overall proportion of NAF is

expected to be higher once an acid rock drainage (ARD) block model has been completed, providing

significant flexibility in materials segregation and handling. The smaller portion of PAF (including

PAF-LC and NAF-HS) materials occur mainly within a halo around the sulphidic ore. Inspection of the

core showed that PAF units in the waste rock should be readily visually identified, with S a good

discriminator of ARD rock types. Although testing focussed on Rockface and Marshall/Reward

projects, it is understood that Bellbird geology is similar, and results and findings can be generally

applied to Bellbird mine materials. A summary of ARD potential by waste rock unit based on results

to date is provided below:

ix


Oxide Waste Rock NAF with occasional zones of PAF/PAF-LC

Transition Waste Rock NAF with occasional zones of PAF/PAF-LC

Distal NAF with occasional zones of PAF/PAF-LC

Proximal NAF with common zones of PAF/PAF-LC

Mineralised Mixed NAF and PAF/PAF-LC

Felsic NAF

Vein (Quartz/Tourmaline) NAF with common zones of PAF/PAF-LC

Over 90% of the unoxidised ore samples were PAF/PAF-LC with high S (generally greater than

2%S), indicating primary ore stockpiles, and residual primary ore zones in underground workings and

open pits will be a potential source of ARD. Oxide ore had much less PAF/PAF-LC as expected, with

over 80% of samples classified NAF. Transition ore samples were approximately 50% NAF.

Specialised testing indicated the presence of iron carbonate, resulting in slow reaction rates and

variable ANC effectiveness. Despite this, kinetic NAG testing of PAF materials indicated significant

lag times before acid conditions develop after exposure to atmospheric oxidation, ranging from

months to several years, but leach column testing would be required to confirm these preliminary

findings. Longer lag times would provide flexibility in management of waste rock seepage during any

temporary storage or short term exposure during operations.

Sulphidic waste rock and ore materials show strong enrichment in a variety of metals/metalloids

including Ag, Bi, Be, Cd, Co, Cs, Cu, Mo, Pb, S, Se, Tl, W and Zn with enrichment increasing with

proximity to ore. A number of samples were also enriched in Fe and Mn, and individual samples were

enriched in As, Ag, As, Bi, Cd, Cu, Hg, Pb, Sb, Se, Tl and Zn.

Water extract testing indicates that the majority waste rock materials will not liberate significant acid,

salinity or metals/metalloids. However, under acid conditions mobilisation of Al, Cd, Co, Cu, Fe, Mn,

Ni, SO4 and Zn, and possibly Pb, can be expected. In addition, PAF materials during the lag phase

and some higher S (>1%S) NAF materials may generate salinity (SO4) and elevated Cu, Mn and Zn

with oxidation. The solubility of metals/metalloids will largely be determined by pH and therefore

control of acid generation will effectively control metal leaching.

Historic mine materials showed varying acid and salinity potential, but were generally metalliferous

and all generated leachates with some degree of elevated metals/metalloids in water extracts,

particularly Cd, Co, Cu, Mn, Ni, Pb and Zn.

Results suggest that tailings from sulphide ore samples will have moderate S values of around 1%S,

but are still likely to be PAF. Tailings showed enrichment in a similar suite of metals/metalloids as the

waste rock and ore, including Ag, Bi, Be, Cd, Co, Cs, Cu, Fe, Mn, Pb, S Mo, Se, Tl, W and Zn. Some

mobilisation of Cd, Co, Cu, SO4, Mn and Zn can be expected during the lag period.

x


Results indicate that the following preliminary segregation criteria based on total S only could be

used for routine classification:

NAF: ≤ 0.4%S

PAF: > 0.4%S

where PAF represents combined NAF-HS, PAF-LC and PAF classes

Results have the following implications for mine materials management:

• Most waste rock from pit and underground development is expected to be NAF and

environmentally benign, and will not require specific management for control of ARD.

Controlling ARD from the smaller portion of PAF (including PAF-LC and NAF-HS) should be

relatively straight forward, but will require selective handling and specific management to

prevent ARD into the long term. Long term options could include:

o in pit or underground disposal below recovery water table levels;

o selective underground disposal of PAF as part of paste backfill; or

o construction of an infiltration control cover system in-pit or ex-pit.

• Subaqueous disposal is the most secure option for controlling sulphide oxidation and ARD,

but the feasibility of this mechanism will depend on long term recovery groundwater and pit

water levels, and the volume of PAF mine materials this can accommodate.

• Placement of PAF underground along with cement backfill is preferred to surface dumping,

but will need to consider the reactivity of the sulphidic materials, and the transmissivity and

sensitivity of the receiving groundwater system.

• Most of the underground decline and other development not associated with ore extraction

would be carried out within distal units, and hence would be expected to be manly NAF, but

horizontal ore drives would become more sulphidic and PAF as the contact with the ore

zones are approached. Scheduling of underground waste rock should attempt to directly

utilise PAF in back fill and avoid bringing PAF materials to surface.

• Seepage and runoff from any surface dumped (or stockpiled) PAF waste rock materials may

require management during operations to mitigate any potential impacts on the receiving

environment. Contingency for treatment during operations may be required, including dump

surface limestone addition and/or blending to help delay onset of acid drainage, and/or

collection of seepage/runoff and treatment.

• Ore and low grade ore materials are likely to be mainly sulphidic and PAF, and represent a

potential source of ARD during operations. Ore and low grade ore stockpiles should be

managed to ensure capture and monitoring of any seepage/runoff, with contingency for

treatment if required. This will be particularly important for low grade materials expected to

be stockpiled for an extended period.

• The final pit voids will include a mix of NAF and PAF materials, with at least a portion likely to

generate acid (particularly exposures of fresh mineralised/residual ore materials), but

understanding the lag times, overall leaching characteristics, and final water quality will

require additional work. Pit water monitoring should be carried out during operations with

again contingency for treatment to help control impacts on the receiving environment. Pit

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closure requirements for the pit will depend on the final distribution and leaching properties of

geochemical rock types in the final walls and floors.

• The stopes and drives close to the ore are likely to be sulphidic and PAF, and underground

seepage water from these zones is expected to be ultimately acidic, although cement backfill

may offset this to some degree. Potential impacts on the groundwater system from

underground water would need to be assessed.

• Dewatering of pits and underground workings is likely to require active management during

operations to ensure water quality of receiving drainage meets compliance. This could entail

water storage on site, water treatment, and/or controlled discharge during wet periods at set

dilution ratios.

• Tailings from fresh ore processing are expected to be PAF, and the proposed TSF will

require management to prevent ARD. The TSF will require a secure low permeability base to

prevent leaching of process water and oxidation products during operations, and is likely to

require an infiltration control cover system for closure. The potential for paste backfill of

tailings into underground workings should be assessed to help reduce the inventory of

tailings requiring surface management.

• Historic mine materials are metalliferous and show varying potential for generating acid,

saline, and metalliferous drainage, although on a localised scale. Given the small volume of

these materials, the uncertainty of the current effects from these materials on the receiving

environment, and the uncertainty in regard to the security of facilities constructed to contain

them, reactivation of any of the old facilities for storage of waste rock and tailings as part of

the proposed Project should allow for re-handling or incorporation of historic mine materials

into management approaches that demonstrate isolation from the receiving environment.

The following programmes are recommended to better understand the geochemical properties of

mine materials and help determine appropriate materials management requirements for operations

and closure:

• Carry out kinetic leach column and batch water extraction testing to better understand the

leaching characteristics of key mine materials. Leach columns provide information on

leaching rates and geochemical evolution under atmospheric oxidation rates that can be

related to field conditions, and results can be used to model the water quality of mine

components during operations and at closure.

• Develop an initial S distribution model using the existing S database for all deposits to better

define the ARD potential of mine development materials using the preliminary S criteria.

• Target further S testing to infill gaps in coverage for the S model, with additional geochemical

characterisation to confirm cut off criteria.

• Carry out specific geochemical assessment of Bellbird and other key deposits not directly

assessed to date.

• Further develop PAF waste rock management options, with priority on preferential placement

of PAF as underground backfill. This may include assessment of potential underground void

contaminant pathways, investigations into cover system designs, seepage/runoff collection

xii


and treatment approaches, pit void backfilling options and modelling of pit and underground

recovery water levels.

• Clarify TSF base design and permeability, and investigate options for tailings infiltration

control cover systems, taking into account the effects of high intensity rainfall events.

• Assess the potential for paste backfill of tailings into underground workings to help reduce

the inventory of tailings requiring surface management

• Carry out preliminary water quality geochemical equilibrium modelling to better define the

likely impacts during operations and closure on surface and groundwater from the various

mine components with varying management options. This kinetic leach column data

recommended above would be a key input to the modelling.

Geochemical Assessment of the Jervois Base Metal Project, Northern Territory 1


1.0 Introduction

Environmental Geochemistry International Pty Ltd (EGi) was commissioned by Nitro Solutions Pty

Ltd on behalf of KGL Resources Pty Ltd (KGL) to carry out a geochemical assessment of the

Jervois Base Metal Project (the Project), located approximately 270 km east-north-east of Alice

Springs, Northern Territory. This work will contribute to an Environmental Impact Statement (EIS)

for the Project. The objectives of the geochemical assessment were to identify issues and

opportunities, and clarify implications for materials handling, storage and construction

considerations, with focus on understanding the following aspects:

• Relative proportions of geochemically problematic waste rock materials (e.g. potentially

acid forming, neutral but metal leaching), leaching characteristics (rates of reaction and lag

times) and potential impacts on the receiving environment;

• Waste rock management implications and options, such as surface versus underground

storage, segregation and selective handling, stockpiling and rehandling, requirements for a

cover system to control ARD;

• Influence of tailings on the water quality of the receiving environment, and management

implications including cover system requirements and treatment contingencies;

• Geochemical characteristics of pit and underground workings and potential impacts on the

receiving environment;

• Geochemistry of ore and low grade ore and implications for stockpile management.

The geochemical assessment included the following tasks:

• Completion of a scoping phase involving a site visit, liaison with relevant project personnel,

compilation of background project data and identification of key information gaps;

• Preparation of a sampling programme in conjunction with site geologists and other relevant

personnel to represent mine materials;

• Collection of samples and arrangement of sample preparation by KGL personnel with

advice from EGi;

• Laboratory testing of samples; and

• Assessment of results and reporting.

2.0 Background and Geology

Exploration and mining activities have occurred on the Project since 1929 and there is significant

existing disturbance across the site. Historic mining disturbances include tailings storage facilities,

waste rock dumps, decommissioned processing plants and equipment, pits, prospecting trenches,

ROMs, water storages and evaporation ponds, an exploration camp, exploration disturbances,

roads and tracks.



The Project would be developed by KGL Resources Pty Ltd (KGL) to extract copper, lead and zinc

ore from a variety of individual deposits, using both underground and open cut mining methods.

Ore would be processed on site using standard flotation methods. The project would produce

approximately 30 Mt of ore, 87 Mt of waste rock and 20 Mt of tailings over a 12 to 15 year mine life.

Development of the project would utilise the existing waste rock dumps and TSF where possible to

minimise the footprint impacted. The key mine components resulting from development and most

relevant to geochemical assessment are waste rock dumps, low grade ore and ore stockpiles,

tailings storage facilities, open cut pits and underground workings.

The project area is arid with dry, hot summers and short, dry winters. Mean annual rainfall is

approximately 300mm, mainly falling between October and March, and sometimes in high intensity

events that cause flooding.

EGi carried out a site visit in September 2017 to support geochemical assessment of the Project.

The site visit involved inspection of the key project areas and existing pits, ore stockpiles and

tailings storages, viewing of representative core, and collection of grab samples of historic waste

rock, tailings and low grade materials.

The main previous mine development on site comprised shallow mining of copper ore from the

oxide zone at the Bellbird deposit, and mining of oxide and sulphide lead-zinc ore at the Green

Parrot deposit. Residual disturbance from development of the Bellbird deposit was relatively minor,

with small waste mullock heaps, drums of stockpiled ore, and small pits/trenches evident on site

(Plates 1 to 3). The Green Parrot development was at a larger scale and required a flotation plant,

with residual disturbance including a small pit (Plate 4), a tailings storage facility (Plate 5), a

possible tailings storage or stockpile of milled ore adjacent to the process plant (Plate 6), a run-of-

mine (ROM) pad (Plate 7) and stockpiled ROM ore (Plate 8).

Because the Bellbird deposit was developed in oxide ore, the residual pits and mine materials are

generally non-sulphidic. One minor exception was observed on the northern end of the workings, in

which it appears a shaft was excavated into the sulphidic zone, with the last materials placed on

the adjacent mullock heap partly sulphidic and showing salt development most likely due to partial

sulphide oxidation (Plates 9 to 10).

Green Parrot stockpiled ore materials included significant sulphide as expected, particularly galena

and sphalerite, but also included oxide copper ore (Plates 11 and 12). The sulphide minerals

showed oxidation effects (white and green-yellow salts), and some local seepage of

metals/metalloids and sulphate salts from the stockpile could be expected.



Plate 1: Bellbird Pit showing shallow workings, dumps of stockpiled oxide copper ore, and side cast waste rock mullock heaps.

Plate 2: Bellbird Pit showing shallow workings, dumps of stockpiled oxide copper ore, and side cast waste rock mullock heaps.



Plate 3: Bellbird Pit showing shallow workings and side cast waste rock mullock heaps.

Plate 4: Green Parrot Pit.



Plate 5: Green Parrot TSF.

Plate 6: Tailings or milled ore storage adjacent to Green Parrot process plant.



Plate 7: Green Parrot ROM pad, stockpiled ore, process plant, and tailings/milled ore storage.

Plate 8: Stockpiled ore from Green Parrot.

ROM Pad

Ore Stockpiles

Tailings/Milled

Ore



Plate 9: Surface salts due to partial sulphide oxidation on northern part of Bellbird Pit development.

Plate 10: Surface salts due to partial sulphide oxidation on northern part of Bellbird Pit development.



Plate 11: Galena-sphalerite ore with white salts and oxide copper ore.

Plate 12: Galena-sphalerite ore with green-yellow salts.



Drill core was examined on site from three holes, KJD212 (Rockface), KJD215 (Rockface) and

KJD216 (Reward). Hole KJD216 was laid out to view the ore zone together with waste rock

extending well into the distal alteration zones either side (30m uphole and 90m downhole),

whereas the two Rockface holes viewed represented mainly the proximal alteration zones either

side of the ore. It is understood that the general geology and mineralisation styles viewed are

typical of copper mineralisation across the site. Application of 10% HCl to rock containing

significant amounts of reactive acid neutralising carbonates (such as calcite and dolomite) results

in vigorous fizzing. During inspection of the core, 10% HCl was applied intermittently to provide an

indication of the presence of reactive carbonate. Observations from core examination are as

follows:

• Ore zones are distinct, with abundant sulphide and commonly massive to semi massive,

with intermittent carbonate veining, and associated with magnetite (Plate 13 to 16).

• The sulphides in ore zones include a high proportion of pyrite.

• Contacts between ore and waste can be very sharp, with non-sulphidic waste rock

immediately adjacent to the ore zone (Plate 17).

• Waste rock in the distal alteration zones is generally devoid of significant sulphide (Plate 18

and 19), apart from occasional pyrite along foliations and associated with quartz veins

(Plate 20 and 21).

• Some zones of significant pyrite are observed outside of ore zones, and although much

less sulphidic than the ore zone, these zones could still be an issue for acid rock drainage

(ARD). Observed waste rock pyritic zones included:

– Pyrite along foliations and disseminated pyrite in Intermediate and proximal

alteration zones (Plate 22 to 24); and

– Magnetite waste zones with significant pyrite and chalcopyrite (Plate 25).

• Occasional carbonate veining (generally thin) was evident throughout the core in waste

and ore zones (Plates 16 and 26), with less common larger veins and breccia in a proximal

alteration and ore zones (Plate 27 and 28), all of which showed moderate fizzing, indicating

moderately effective acid buffering in local intervals. Generally, however, the core showed

a lack of fizzing, suggesting only limited background neutralising potential.



Plate 13: Mineralised zone with abundant chalcopyrite and pyrite. Dark phases are mainly magnetite. Hole KJD216, 640.65m.

Plate 14: Mineralised zone with massive sulphide dominated by pyrite with lesser chalcopyrite. Hole KJD215, 613.25m.

Chalcopyrite

Pyrite

Chalcopyrite

Pyrite

Magnetite



Plate 15: Mineralised zone with massive sulphide dominated by chalcopyrite with lesser pyrite. Hole KJD216, 645.85m.

Plate 16: Mineralised zone with abundant chalcopyrite and pyrite, and with carbonate veining. Dark phases are mainly magnetite. Hole KJD216, 641.90m.

Plate 17: Sharp contact between the mineralised zone and non-sulphidic waste rock. Hole KJD216, 647.27m to 650.83m.

Carbonate

Veins

Waste Ore



Plate 18: Typical non-sulphidic pelite waste rock in the distal alteration zone. Hole KJD216, 688.48 to 691.86m.

Plate 19: Typical non-sulphidic psammite waste rock in the distal alteration zone. Hole KJD216, 664.39 to 667.73m.

Plate 20: Minor pyrite on foliations in distal alteration zone. Hole KJD216, 571.15m.



Plate 21: Minor pyrite associated with quartz vein in distal alteration zone. Hole KJD216, 568.00m.

Plate 22: Pyrite on foliations and disseminated pyrite in intermediate alteration zone. Hole KJD216, 580.2m.



Plate 23: Disseminated pyrite in intermediate alteration zone. Hole KJD216, 581.5m.

Plate 24: Pyrite on foliations and disseminated pyrite in intermediate alteration zone. Hole KJD216, 583.4m.

Plate 25: Waste proximal alteration zone with massive magnetite and significant pyrite and chalcopyrite. Hole KJD215, 610.0m.



Plate 26: Typical thin carbonate veining in distal alteration zone. Hole KJD216, 557.5m.

Plate 27: Larger carbonate veining in ore zone. KJD212, 687.3m.

Plate 28: Carbonate breccia in proximal alteration zone. KJD215, 595.65m.



4.0 Sample Selection and Preparation

4.1 Drill Hole Samples for Future Waste Rock and Ore

A total of 662 drill hole samples were selected by KGL geologists in conjunction with EGi to capture

geological and spatial variation in proposed mine materials from declines, stopes and drives in

underground development at Rockface and Marshall/Reward, and open cut development at

Marshall/Reward. The sampling focused on Rockface and Marshall/Reward deposits, since these

currently represent the bulk of the resource, and would be developed first.

The key aims of the testing were to define the geochemical properties of mine materials, and

develop ARD segregation criteria based on a combination of geology and indicator test parameters

that can be used throughout the deposits tested to better define proportions of ARD rock types.

These criteria can then be extended to other deposits not directly tested.

The approach used to select a representative sample set from available drill hole samples involved

reviewing, adapting and assessing the Project geological and assay database to understand the

distribution of rock types; and selection of samples to account for variation of lithology and

alteration types for oxidised and unoxidised ore and waste, variation in sulphide content, and the

range of S, Ca and Mg for each key rock type, while also capturing spatial distribution. KGL

geologists provided a list of available pulverised samples, and samples were selected from this set

wherever possible to save time and costs involved in sample preparation from core.

KGL provided a merged geology and assay database split into project areas. Alteration domains

and lithological descriptions in this database were summarised based on combined legacy codes

and new codes in consultation with KGL geologists. Ore and waste for Rockface and

Marshall/Reward Underground development were differentiated in the merged database with a

nominal cut off of 1.5%Cu, based on advice from KGL geologists. For the Marshall/Reward Open

Cut a 0.5%Cu cut off was used. This did not accurately distinguish between ore and waste, but was

used to provide a guide to the distribution of S, Ca and Mg in ore and waste zones to ensure the

range was covered in the geochemical sampling.

Matrices of alteration domain and lithology were produced from the supplied database for Rockface

Underground, Marshall/Reward Underground and Marshall/Reward Open Cut, and the relative

proportions of alteration/lithology combinations were used to help focus the sampling on key

alteration/lithology types.

Table 1 is a matrix showing the relative abundance of alteration domain and lithological

combinations for Rockface Underground. Oxidised intervals (codes CO, MO, PO and SO) were

excluded from this since fresh materials will dominate development, apart from a small section in

the upper part of the decline. Specific holes were selected for sampling to capture the oxide section

of the decline. Table 2 shows the count of selected samples by alteration domain and lithological

combinations. The distribution of samples does not match up exactly to the proportions in Table 1,

but the main lithology/alteration combinations are well represented, with some emphasis on

mineralised zone waste rock to adequately capture the range of sulphide content not as well

represented in the available ore samples, which is important for assessment of residual stope

surfaces.



Table 1: Relative abundance of alteration and lithological combinations for Rockface Underground waste rock and ore.

Table 2: Count of selected samples by alteration and lithological combinations for Rockface Underground waste rock and ore.

Table 3 shows the relative abundance of alteration domain and lithological combinations for

Marshall/Reward Underground. In this case, the samples were all at depth, and filtering the oxide

portion was unnecessary. The upper portion of decline development was all within the open pit

footprint, and hence the open cut sample selection for Marshall/Reward will also cover any decline

development within the oxide zone. The sample count for Marshall/Reward Underground is shown

in Table 4, which again shows the sampling covers the main alteration domain/lithological

combinations but with additional emphasis on mineralised waste rock as for Rockface. Note that

Rockface Waste Rock - Excludes Oxidised Samples (CO, MO, PO, SO)

Pelite PsammiteMagnetite/

IronstonePegmatite

Quartz

Vein

Calc-

Silicate

Felsic

SchistMarble Porphyry

Tourmaline

Vein

Distal 76.3% 3.8% 0.1% 0.0% 0.0% 0.1% 0.0% 0.0% 0.0% 0.0% 80.3%

Proximal 9.8% 2.7% 0.2% 0.1% 0.0% 0.1% 0.0% 0.0% 0.0% 0.0% 13.0%

Mineralised 2.5% 0.2% 0.9% 0.0% 0.0% 0.1% 0.0% 0.0% 0.0% 0.0% 3.7%

Felsic 0.0% 0.0% 0.0% 2.5% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 2.5%

Other 0.0% 0.0% 0.0% 0.0% 0.6% 0.0% 0.0% 0.0% 0.0% 0.0% 0.6%

Total 88.7% 6.7% 1.1% 2.6% 0.6% 0.2% 0.0% 0.0% 0.0% 0.0% 100.0%

Rockface Ore - Excludes Oxidised Samples (CO, MO, PO, SO)


IronstonePegmatite

Quartz

Vein

Calc-

Silicate

Felsic


Tourmaline

Vein

Distal 4.7% 2.9% 0.3% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 7.9%

Proximal 2.4% 0.9% 0.2% 0.0% 7.5% 0.0% 0.0% 0.0% 0.0% 0.0% 11.0%

Mineralised 19.2% 4.0% 55.6% 0.0% 0.0% 1.3% 0.0% 0.2% 0.0% 0.0% 80.4%

Felsic 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

Other 0.0% 0.0% 0.0% 0.0% 0.7% 0.0% 0.0% 0.0% 0.0% 0.0% 0.7%

Total 26.3% 7.8% 56.2% 0.0% 8.2% 1.3% 0.0% 0.2% 0.0% 0.0% 100.0%

Lithology

Alteration

Domain

Lithology

Total

TotalAlteration

Domain

Rockface Selected Waste Rock Samples


Ironstone

Pegmat

ite

Quartz

Vein

Calc-

Silicate

Felsic


Tourmaline

Vein

Distal 95 8 103

Proximal 38 11 49

Mineralised 34 4 16 54

Felsic 6 6

Other 6 1 7

Total 167 23 16 6 6 0 0 0 0 1 219

Rockface Selected Ore Samples


Ironstone

Pegmat

ite

Quartz

Vein

Calc-

Silicate

Felsic


Tourmaline

Vein

Distal 1 1

Proximal 0


Felsic 0

Other 0

Total 6 4 16 0 0 0 0 0 0 0 26

Total

Lithology

Alteration

Domain

Lithology

Alteration

DomainTotal



there is a large proportion of mineralisation within the distal alteration domain, which suggests a

possible issue in assigning alteration domains based on legacy codes for this deposit.

Table 3: Relative abundance of alteration and lithological combinations for Marshall/Reward Underground waste rock and ore.

Table 4: Count of selected samples by alteration and lithological combinations for Marshall/Reward Underground waste rock and ore.

The relative abundance of alteration domain and lithological combinations for Marshall/Reward

Open Cut are shown in Table 5. Oxide and transition intervals were assigned separate alteration

domains, given the strong controls oxidation will have on both sulphide and carbonate content.

Marshall/Reward Underground Waste Rock


IronstonePegmatite

Quartz

Vein

Calc-

Silicate

Felsic

SchistMarble Granite

Tourmaline

Vein

Distal 54.6% 20.9% 0.0% 0.0% 0.0% 1.9% 1.6% 0.3% 0.0% 0.0% 79.3%

Proximal 2.3% 3.9% 0.1% 0.0% 0.0% 0.8% 0.1% 0.0% 0.0% 0.0% 7.2%

Mineralised 6.8% 0.1% 0.9% 0.0% 0.0% 0.2% 0.0% 0.7% 0.0% 0.0% 8.8%

Felsic 0.0% 0.0% 0.0% 3.3% 0.0% 0.0% 0.0% 0.0% 0.1% 0.0% 3.4%

Other 0.0% 0.0% 0.0% 0.0% 1.2% 0.0% 0.0% 0.0% 0.0% 0.2% 1.4%

Total 63.7% 24.9% 1.0% 3.3% 1.2% 2.9% 1.8% 1.0% 0.1% 0.2% 100.0%

Marshall/Reward Underground Ore


IronstonePegmatite

Quartz

Vein

Calc-

Silicate

Felsic


Tourmaline

Vein

Distal 36.0% 2.8% 0.0% 0.0% 0.0% 0.3% 0.6% 0.0% 0.0% 0.0% 39.7%

Proximal 2.1% 2.5% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 4.5%

Mineralised 40.1% 3.0% 7.4% 0.0% 0.0% 0.0% 0.0% 0.6% 0.0% 0.0% 51.1%

Felsic 0.0% 0.0% 0.0% 0.8% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.8%

Other 0.0% 0.0% 0.0% 0.0% 3.6% 0.0% 0.0% 0.0% 0.0% 0.2% 3.8%

Total 78.2% 8.3% 7.4% 0.8% 3.6% 0.3% 0.6% 0.6% 0.0% 0.2% 100.0%

Lithology

Alteration

Domain

Lithology

Total

Alteration

DomainTotal

Marshall/Reward Underground Selected Waste Rock Samples


IronstonePegmatite

Quartz

Vein

Calc-

Silicate

Felsic


Tourmaline

Vein

Distal 66 25 9 2 1 103

Proximal 12 29 4 1 1 47


Felsic 13 13

Other 13 1 14

Total 109 54 6 13 14 10 2 5 0 1 214

Marshall/Reward Underground Selected Ore Samples


IronstonePegmatite

Quartz

Vein

Calc-

Silicate

Felsic


Tourmaline

Vein

Distal 1 1

Proximal 1 2 3

Mineralised 6 12 16 1 35

Felsic 3 3

Other 1 1

Total 8 14 16 4 0 0 0 0 0 1 43

Alteration

Domain

Lithology

Total

Alteration

Domain

Lithology

Total



Oxide was defined as regolith lithology, or CO, SO or MO oxidation. Transition was defined as PO

oxidation. The sample count for Marshall/Reward Underground in Table 6 shows the sampling

covers the main alteration domain/lithological combinations, with some additional emphasis on

oxidised materials, as this could affect the S forms and result in overestimation of ARD potential,

and also additional emphasis on mineralised waste rock as with the other deposits. Similar to the

Marshall/Reward Underground, there is a large proportion of mineralisation within the distal

alteration domain, assumed to be due to potential issues in assigning alteration domains based on

legacy codes for Marshall/Reward.

Table 5: Relative abundance of alteration and lithological combinations for Marshall/Reward Open Cut waste rock and ore.

Marshall/Reward Pit Waste Rock


IronstonePegmatite

Quartz

Vein

Calc-

Silicate

Felsic


Tourmaline

VeinSaprolite

Oxidised 7.3% 3.9% 0.0% 0.1% 0.1% 0.0% 0.0% 0.1% 0.0% 0.0% 0.4% 11.9%

Transition 10.4% 5.6% 0.0% 0.0% 0.1% 0.2% 0.1% 0.3% 0.0% 0.0% 0.0% 16.6%

Distal 37.0% 23.9% 0.0% 0.0% 0.0% 0.3% 0.6% 0.1% 0.0% 0.0% 0.0% 62.0%

Proximal 1.3% 3.1% 0.0% 0.0% 0.0% 0.7% 0.0% 0.0% 0.0% 0.0% 0.0% 5.1%

Mineralised 2.3% 0.0% 0.1% 0.0% 0.0% 0.4% 0.0% 0.0% 0.0% 0.0% 0.0% 2.7%

Felsic 0.0% 0.0% 0.0% 1.2% 0.0% 0.0% 0.0% 0.0% 0.1% 0.0% 0.0% 1.2%

Other 0.0% 0.0% 0.0% 0.0% 0.5% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.5%

Total 58.3% 36.4% 0.1% 1.2% 0.6% 1.7% 0.7% 0.5% 0.1% 0.0% 0.4% 100.0%

Marshall/Reward Pit Ore


IronstonePegmatite

Quartz

Vein

Calc-

Silicate

Felsic


Tourmaline

VeinSaprolite

Oxidised 6.7% 9.3% 0.0% 0.0% 0.0% 0.0% 0.0% 0.5% 0.0% 0.0% 0.0% 16.5%

Transition 3.3% 6.8% 0.0% 0.0% 0.0% 0.3% 0.2% 0.2% 0.0% 0.0% 0.0% 10.8%

Distal 15.6% 24.7% 0.0% 0.0% 0.0% 0.0% 0.1% 0.0% 0.0% 0.0% 0.0% 40.3%

Proximal 2.9% 1.3% 0.0% 0.0% 0.0% 2.8% 0.0% 0.0% 0.0% 0.0% 0.0% 7.0%

Mineralised 20.8% 0.0% 0.8% 0.0% 0.0% 0.4% 0.0% 0.1% 0.0% 0.0% 0.0% 22.1%

Felsic 0.0% 0.0% 0.0% 1.6% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 1.6%

Other 0.0% 0.0% 0.0% 0.0% 1.7% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 1.7%

Total 49.2% 42.2% 0.8% 1.6% 1.7% 3.5% 0.2% 0.8% 0.0% 0.0% 0.0% 100.0%

Alteration

Domain

Lithology

Total

Alteration

Domain

Lithology

Total



Table 6: Count of selected samples by alteration and lithological combinations for Marshall/Reward Open Cut waste rock and ore.

Figures 1 to 3 are box plots that show the distribution of S (as an indication of pyrite content), and

Ca and Mg (as an indication of carbonate content) for each deposit, split by alteration domains,

with ore as a separate domain. These distributions were used to guide sample selection to ensure

that the range of S, Ca and Mg was represented for each domain.

The ranges (minimum, median and maximum) of S, Ca and Mg represented by the samples

selected for each deposit split by alteration domain are shown in Figures 4 to 6. The figures

demonstrate that the S, Ca and Mg distributions in Figures 1 to 3 are generally well represented by

the selected samples for the main domains. Felsic and other (quartz vein and tourmaline vein)

domains are less well represented in the samples selected, but only account for a small proportion

of the materials to be mined.

The number of samples selected for the key materials types and assay values as part of the

sample selection process was considered sufficient to produce a defendable representative sample

set to ensure confident assessment of the overall ARD potential of the Project materials, and

development of reliable segregation criteria.

Sample preparation was arranged by KGL personnel and EGI was provided with -75µm samples

for testing.

Marshall/Reward Pit Selected Waste Rock Samples


IronstonePegmatite

Quartz

Vein

Calc-

Silicate

Felsic


Tourmaline

VeinSaprolite

Oxidised 17 8 25

Transition 6 7 1 1 15

Distal 15 17 32

Proximal 2 14 1 17

Mineralised 12 4 16

Felsic 2 2

Other 0

Total 52 46 1 2 0 5 1 0 0 0 0 107

Marshall/Reward Pit Selected Ore Samples


IronstonePegmatite

Quartz

Vein

Calc-

Silicate

Felsic


Tourmaline

VeinSaprolite

Oxidised 7 7 14

Transition 11 7 18

Distal 2 4 6

Proximal 3 3

Mineralised 4 4

Felsic 0

Other 0

Total 27 18 0 0 0 0 0 0 0 0 0 45

Alteration

Domain

Lithology

Total

Alteration

Domain

Lithology

Total



Figure 1: Box plots showing the distribution of S, Ca and Mg for Rockface Underground split by alteration domain. Box plots have 5th, 10th, 25th, 50th (median), 75th, 90th and 95th percentiles, and

mean marked.



Figure 2: Box plots showing the distribution of S, Ca and Mg for Marshal/Reward Underground split by alteration domain. Box plots have 5th, 10th, 25th, 50th (median), 75th, 90th and 95th percentiles,

and mean marked.



Figure 3: Box plots showing the distribution of S, Ca and Mg for Marshal/Reward Open Pit split by alteration domain. Box plots have 5th, 10th, 25th, 50th (median), 75th, 90th and 95th percentiles, and

mean marked.



Figure 4: Plots showing the range of S, Ca and Mg values (minimum, median and maximum) represented by the samples selected for Rockface Underground split by alteration domain.



Figure 5: Plots showing the range of S, Ca and Mg values (minimum, median and maximum) represented by the samples selected for Marshall/Reward Underground split by alteration domain.



Figure 6: Plots showing the range of S, Ca and Mg values (minimum, median and maximum) represented by the samples selected for Marshall/Reward Open Pit split by alteration domain.



4.2 Historic Mine Materials

A total of 22 samples were collected from historic mine materials on site to provide some initial

guide to potential legacy geochemistry issues. Most samples were associated with the Green

Parrot development as this produced the most materials, including tailings, stockpiles, and possible

milled ore. Grab samples of 10 to 15kg were collected by shovel, and comprised:

• Two mullock samples with white salts from Bellbird representing apparent sulphidic

materials excavated from a nearby shaft;

• Eight tailings samples from the Green Parrot TSF collected along a line at variable intervals

from the original spigot to capture grain size and density variation;

• Five samples of tailings or possible milled ore adjacent to the Green Parrot process plant,

representing various grain sizes, and materials present; and

• Seven low grade ore/ore samples at various points around the stockpiles on the Green

Parrot ROM.

A detailed sample list is provided in Appendix B, Table B7.

Sample preparation was carried out by International Resource Laboratories (IRL) (Brisbane), which

involved drying (as required), crushing to a nominal -4mm where required, splitting, and pulverising

a 500g split to -75µm.

4.3 Metallurgy Samples

A total of 20 ore feed and tailings samples of 0.25kg to 5kg were provided by KGL from

metallurgical test work carried out on ore from Rockface, Marshall/Reward, Green Parrot and

Bellbird:

• Rockface, 8 samples – 1 composite ore and 3 individual ore interval samples, and 4

rougher tailings samples from metallurgical testing of the composite sample;

• Marshall/Reward, 6 samples – 1 ore feed and 1 final tailings each from a Pb/Zn composite,

a transitional Cu composite and a sulphide Cu composite;

• Green Parrot, 4 samples - 1 ore feed and 1 final tailings each from a transitional Cu

composite and a sulphide Cu composite;

• Bellbird, 2 samples – 3 individual sulphide ore feed combined into one sample and 3

individual sulphide final tailings combined into one sample.

A detailed sample list is provided in Appendix B, Table B13.

Only rougher tailings were available for Rockface, but the proportion of cleaner tailings generated

in the metallurgical testing was minor at 0.5 to 1.0% of the feed, compared to 91 to 93% of the feed

for the rougher tailings. Four rougher tailings samples were selected for testing, with S values

ranging from 0.75 to 1.08%S. The highest S measured in the cleaner tailings was 8.61%S, and at

1% of the feed this equates to an increase in the combined tailings of only 0.08%S, confirming the

rougher tailings are sufficiently representative of the final tailings.



The tailings samples were provided already finely ground (-75 to -180 µm) and did not require

further sample preparation, except that the individual tailings samples from Bellbird Sulphide

Composite 1, 2 and 3 were combined by equal weight into one sample.

Sample preparation on ore feed samples was carried out by IRL. The Rockface ore feed samples

were coarse at up to 10mm, and these were crushed, split and pulverised for testing. Individual ore

feed samples for Bellbird (Bellbird Sulphide Composite 1, 2 and 3) were composited by equal

weight into one sample, which was split and pulverised. All other ore feed samples were split and

pulverised.

5.0 Methodology

Leco total sulphur (S) and carbon (C) was completed on all 662 waste rock and ore samples, 22

historic mine material samples, and 20 metallurgical samples. The following standard geochemical

characterisation testing was carried out on a subset:

• pH1:2 and electrical conductivity (EC)1:2 on deionised water extracts – 300 selected waste

rock and ore samples, all 22 historic mine material samples, and all 20 metallurgical

samples;

• acid neutralising capacity (ANC) – 513 selected waste rock and ore samples, all 22 historic

mine material samples, and all 20 metallurgical sample;

• net acid producing potential (NAPP) calculated from total S and ANC - 513 selected waste

rock and ore samples, all 22 historic mine material samples, and all 20 metallurgical

sample; and

• single addition net acid generation (NAG) test - 513 selected waste rock and ore samples,

all 22 historic mine material samples, and all 20 metallurgical sample.

Additional specialised testing was carried out on selected samples to further characterise ARD

geochemistry, as follows:

• acid buffering characteristic curve (ABCC) testing to define the relative availability of the

ANC measured – 25 selected waste rock and ore samples and 10 selected historic mine

material samples;

• sequential NAG testing of higher S samples to ensure oxidation of all pyrite and improve

predictions of total acid potential – 25 selected waste rock and ore samples and 7 selected

historic mine material samples;

• sulphur speciation to obtain a guide to the proportion of pyritic S – 30 selected waste rock

and ore samples and 10 selected historic mine material samples; and

• carbon speciation to obtain a guide to the proportion of carbonate C – 66 selected waste

rock and ore samples and 15 selected historic mine material samples; and

• kinetic NAG testing of higher S samples to check pyrite reactivity and to provide an

indication of lag times – 12 selected waste rock and ore samples.



In addition, selected samples were assayed for the following to identify any potential elemental

concerns and to provide initial elemental solubility data:

• multi-element testing of solids by multi acid digest methods to assess elemental

enrichment – 30 selected waste rock and ore samples, all 22 historic mine material

samples and all 10 metallurgical tailings samples; and

• pH, EC, acidity/alkalinity and multi-element scans of single stage deionised water batch

extracts at a ratio of 1 part solid to 2 parts water and 3 hour rotation to assess initial

elemental solubility – all 22 historic mine material samples and all 10 metallurgical tailings

samples.

• pH, EC, acidity/alkalinity and multi-element scans of single stage deionised water batch

extracts at a ratio of 1 part solid to 5 parts water and 3 hour rotation to assess initial

elemental solubility – 30 selected waste rock and ore samples. Note that a higher water

ratio was used due to low sample weights.

A general description of AMD test methods and calculations used is provided in Appendix A.

Water extractions for pH, EC and multi-element testing were carried out on crushed or as received

materials for historic mine material and metallurgical samples. Water extracts for pH, EC and multi-

element testing of waste rock and ore samples were carried out on pulverised samples as these

were the only samples readily available. Pulverised samples were used for all other tests.

The sulphur speciation procedure involved Leco total S, chromium reducible sulphur (CRS) and

KCl digestion to help differentiate pyritic S, acid forming sulphate, non-acid forming sulphate and

other S forms (including organic S, jarosite S and elemental S).

Total S and C analyses were arranged by KGL. CRS and multi-element analyses of sample solids

were carried out by ALS Laboratory Group (Brisbane). Analysis of deionised water batch extracts

were carried out by ALS Laboratory Group (Sydney). Analyses of KCl digest solutions were carried

out by Levay & Co. Environmental Services (Adelaide). All other analyses were carried out by EGi.

6.0 Geochemical Characterisation Results for Waste Rock and Ore Samples

Acid forming characteristics of waste rock and ore samples are presented in Appendix B, Table B1,

comprising pH and EC of water extracts, total S, maximum potential acidity (MPA), ANC, NAPP,

ANC/MPA ratio and single addition NAG. Results are discussed in the following subsections.

6.1 pH and EC

The pH1:2 and EC1:2 results were determined by equilibrating the sample in deionised water for

approximately 16 hours at a solid to water ratio of 1:2 (w/w). This gives an indication of the inherent

acidity and salinity of the waste material when initially exposed in a waste emplacement area.



The pH1:2 values ranged from 3.1 to 9.6, with most samples (80%) showing no inherent acidity with

a pH greater than 6. Twenty eight samples had acidic pH values less than 5.

EC1:2 values ranged from 0.05 to 13.06 dS/m with most samples (75%) falling within the non-saline

to slightly saline range with an EC of 0.8 dS/m or less. Thirty one of the samples were saline

(greater than 1.6 dS/m), of which 22 also had pH values less than 5.

Figure 7 is a plot of pH1:2 and EC1:2 versus total S, which shows that the lower pH values (< pH 5)

and the higher EC values (>1.6 dS/m) are generally associated with higher S (>1%S) samples.

This indicates that lower pH and higher EC values are primarily the result of partial sulphide

oxidation (particularly pyrite) and generation of soluble salts occurring between pit exposure and

sample testing. Results indicate low immediately available acidity and salinity in the samples

except where sulphide is present and has partially oxidised.

Figure 7: Plot showing pH1:2 and EC1:2 versus total S for waste rock samples.

6.2 Acid Base (NAPP) Results

Total S showed a broad range from below detection to 31%S. Figure 8 is a box plot of the

distribution of S split by rock unit. The plot shows that the greater majority (≥75%) of oxide waste,

transition waste, fresh distal altered and felsic waste rock types have relatively low total S of 0.3%S

or less. The S distributions increase with proximity to ore, with proximal altered waste rock distinctly

higher than distal waste rock, and mineralised altered waste rock higher than proximal, as per

geological observations. The S in ore increases with decreasing oxidation, and the ore zones have

the highest S of all mine materials, again as expected from geological observations.



ANC ranged up to 792 kg H2SO4/t. Figure 9 is a box plot of the distribution of ANC split by rock

unit. The plot shows that ANC is relatively low overall, with medians of less than 20 kg H2SO4/t, but

with a broad range in values. Oxide and transition waste rock have distinctly lower median ANC

values than fresh waste rock samples, at less than 8 kg H2SO4/t. The unoxidised ore samples have

the lowest ANC, with a median of 0 kg H2SO4/t.

The NAPP value is an acid-base account calculation using measured total S and ANC values. It

represents the balance between the MPA and ANC. A negative NAPP value indicates that the

sample may have sufficient ANC to prevent acid generation. Conversely, a positive NAPP value

indicates that the material may be acid generating. Note that sulphidic materials with sufficient ANC

to prevent acid generation may still produce saline and metalliferous drainage under circum-neutral

pH conditions.

Figure 10 is an acid-base account plot of ANC versus total S split by waste rock unit. Figure 11 is

the same as Figure 10, but re-scaled to better represent S below 5%S and ANC values below

200 kg H2SO4/t. The NAPP zero line is shown which defines the NAPP positive and NAPP negative

domains, and the line representing an ANC/MPA ratio value of 2 is also plotted. Note that the

NAPP = 0 line is equivalent to an ANC/MPA ratio of 1. The ANC/MPA ratio is used as an indication

of the relative factor of safety within the NAPP negative domain. Usually a ratio of 2 or more

signifies a high probability that the material will remain circum-neutral in pH and thereby should not

be problematic with respect to acid drainage.

The plots show a broad combination of S and ANC values. The mineralised unit samples have the

highest S and highest NAPP values, and all but two felsic samples plot in the NAPP negative

domain. Samples from the remaining rock units plot more evenly in the NAPP positive and NAPP

negative domains. Note that oxidised waste rock samples still include samples with elevated S and

low ANC, plotting in the NAPP positive domain.

Figure 12 is an acid-base account plot of ANC versus total S for ore samples split by oxidation, with

Figure 13 a re-scaled version of the same plot. The vast majority (95%) of the unoxidised ore

samples plots in the NAPP positive domain. The transition and oxide ore samples show a broader

distribution of S and ANC values across the NAPP positive and NAPP negative domains.



Figure 8: Box plot showing the distribution of S split by rock unit. Box plots have 5th, 10th, 25th, 50th (median), 75th, 90th and 95th percentiles, and mean marked.

Figure 9: Box plot showing the distribution of ANC split by rock unit. Box plots have 5th, 10th, 25th, 50th (median), 75th, 90th and 95th percentiles, and mean marked.



Figure 10: Acid-base account (ABA) plot split by waste rock unit.

Figure 11: As for Figure 10 with expanded axes.



Figure 12: Acid-base account (ABA) plot for ore split by oxidation.




6.3 Single Addition NAG Results

NAG test results are used in conjunction with NAPP values to classify samples according to acid

forming potential. Generally, a NAGpH value less than 4.5 indicates a sample may be acid forming.

Figure 14 is an ARD classification plot showing NAGpH versus NAPP value, with results split by

waste rock unit. Figure 15 is the same as Figure 14, but with an expanded NAPP axis to better

represent the range -200 to 200 kg H2SO4/t. Figure 16 and 17 are ARD classification plots for ore

samples split by oxidation. Potentially acid forming (PAF), non-acid forming (NAF) and uncertain

(UC) classification domains are indicated. A sample is classified PAF when it has a positive NAPP

and NAGpH < 4.5, and NAF when it has a negative NAPP and NAGpH ≥ 4.5. Samples are

classified uncertain when there is an apparent conflict between the NAPP and NAG results, i.e.

when the NAPP is positive and NAGpH ≥ 4.5, or when the NAPP is negative and NAGpH < 4.5.

The plots show that most samples have consistent NAPP and NAGpH results, plotting in either the

PAF or NAF domain. Eighty two samples had conflicting NAPP and NAGpH results, with 76

samples plotting in the upper right uncertain domain and six samples plotting in the lower left

uncertain domain.

A total of 287 samples plot in the NAF domain, most (80%) of which have ANC/MPA ratios of 2 or

more. Sixteen samples have elevated S of greater than 0.5%S and ANC/MPA ratios less than 2,

and there is uncertainty as to whether the readily available buffering would be sufficient to account

for all the acid generated by pyrite in these samples. ABCC, S speciation and sequential NAG

testing were carried out to confirm the classification of these samples. Fifteen samples have

elevated S of greater than 1%S, and are classified NAF high S (NAF-HS) due to potential for these

NAF materials to release significant dissolved metals/metalloids and salinity. Leach column testing

would be required to determine contaminant leaching potential for NAF-HS materials.

There are 144 samples that plot in the PAF domain. Many of these show NAG values to pH 7.0

that are much higher than the NAG values to pH 4.5, particularly the ore samples. This most likely

reflects latent acidity released by dissolved metals such as Cu and Zn into the NAG solution, which

are soluble above pH 4.5. Eight of the PAF samples have low S values of 0.5%S or less and NAG

values to pH 4.5 of 5 kg H2SO4/t or less and are expected to be PAF but with a lower capacity to

generate acid (PAF-LC). There are 40 samples with NAG values to pH 4.5 of 5 kg H2SO4/t or less

and with S values above 0.5%, and ABCC, S speciation and sequential NAG testing were carried

out to confirm the classification of these samples.

Of the 76 samples that plot in the upper right uncertain domain, 29 samples have low total S of

0.5%S or less, and the samples are expected to be NAF since the single addition NAG test would

have accounted for all pyritic S in the sample. The other 47 samples have greater than 0.5%S, and

the single addition NAG test may not have accounted for all pyritic S in the sample. ABCC, S

speciation and sequential NAG testing were carried out to confirm the classification of these

samples.

NAG testing of the six samples that plot in the lower left uncertain domain indicates that these

samples are likely to be acid generating but low capacity (PAF-LC) indicating the ANC is not readily

available. ABCC, S speciation and sequential NAG were carried out to confirm the classification of

these samples.



Figure 14: ARD classification plot showing NAGpH versus NAPP, split by waste rock unit.

Figure 15: As for Figure 8 with an expanded NAPP axis.



Figure 16: ARD classification plot for ore samples showing NAGpH versus NAPP, split by oxidation.

Figure 17: As for Figure 8 with an expanded NAPP axis.



Figures 14 to 17 also show some broad grouping by rock types. The oxidised and transition waste

rock and ore samples mainly plot in the NAF and upper right uncertain domains. Distal and felsic

samples plot mainly in the NAF domain. All but 5 unoxidised ore samples plot in the PAF domain.

The remaining proximal, mineralised and vein samples show a spread across the NAF, PAF and

uncertain domains.

6.4 Sequential NAG Testing

When testing samples with high sulphide contents it is common for oxidation to be incomplete in

the single addition NAG test. Sequential NAG testing overcomes this limitation to an extent through

successive additions of peroxide on the same sample. Sequential NAG testing was carried out to 5

stages on 27 selected waste rock and ore samples to better determine the acid potential. Results

are presented in Appendix B, Table B2.

Sixteen samples were NAPP positive at 1 to 160 kg H2SO4/t but had zero or low NAG acidities to

pH 4.5. Samples 14115, 14175, 14199, 14652, 14662, 14755 and 14557 had low to moderate ANC

values of less than 30 kg H2SO4/t and released only minor acid in stages 1 to 2, indicating the

NAPP values overestimate the total acid potential for these samples. Sample 14562 also had a

moderate ANC of less than 30 kg H2SO4/t and released borderline acidity to pH 4.5 of

0.2 kg H2SO4/t in the single addition NAG test, but no acidity to pH 4.5 in the sequential NAG test,

indicating this samples is NAF. Samples 14093, 14206, 14240, 14628 and 14526 released greater

than 5 kg H2SO4/t to pH 4.5 in the sequential NAG test, confirming a PAF classification, but with

capacities much lower than the NAPP values. Sample 14208 had a moderate S of 1.56%S and a

moderate ANC of 47 kg H2SO4/t, but did not release acid in any of the 5 sequential NAG stages,

suggesting a NAF classification. The remaining 2 NAPP positive samples 14099, and 14722 had

high S or greater than 6%S and high ANC values of greater of 80 kg H2SO4/t and greater, and did

not release any acid in the 5 stages, indicating that if these samples are PAF, there would be an

extended lag of several years before acid would be released.

Nine samples were NAPP negative with a NAGpH of 4.5 or greater and sequential NAG testing

was carried out to check for acid production after additional stages of peroxide addition. Sample

14230 produced minor acid in stages 2 and 3, confirming this sample is likely to be PAF-LC. None

of the other samples produced acid in any of the 5 stages, confirming they are likely to be NAF.

Samples 14130 and 14764 were NAPP negative but had NAGpH values less than 4.5. Sequential

NAG testing was carried out to determine the total acid capacity. The cumulative sequential NAG

acidity to pH 4.5 was 1 kg H2SO4/t, confirming these samples are likely to be PAF-LC.

6.5 Kinetic NAG Testing

Kinetic NAG tests provide an indication of the kinetics of sulphide oxidation and acid generation for

a sample. Kinetic NAG testing was carried out on 12 selected PAF samples with S values greater

than 0.7% S and ANC ranging from 0 to 34 kg H2SO4/t. The kinetic NAGpH and temperature

profiles are presented in Appendix C, Figures C1 to C12.

Typically, there will be a distinct temperature peak of greater than 50°C in the kinetic NAG profile

for samples with pyritic S greater than about 0.7%S. Samples 14093 (Figure C1), 14128 (Figure



C3), 14130 (FigureC4), 14175 (Figure C5), 14206 (Figure C6) and 14567 (Figure C8) show

subdued temperature profiles, with total S values of 0.7% to 2.1%S, indicating either only partial

pyrite oxidation or the presence of some non pyritic S forms. The remaining 6 samples all have

distinct temperature peaks, confirming the presence of significant pyrite.

The time to pH 4 in the kinetic NAG test can be used to estimate the lag time before acid conditions

develop in a sample under atmospheric oxidation conditions.

Samples 14093 (Figure C1), 14106 (Figure C2), 14128 (Figure C3) and 14175, (Figure C5) had

low ANC values of 9 to 12 kg H2SO4/t, but showed delays of 89 to 286 minutes before dropping

below pH 4, indicating lags of 1 year or more before acid conditions would develop after exposure

to atmospheric conditions.

Samples 14243 (Figure C7), 14652 (Figure C10) and 14662 (Figure C11) also had low ANC values

of 9 to 12 kg H2SO4/t but showed faster reactions, with delays of 11 to 37 minutes before dropping

below pH 4, indicating lags of 2 to 6 months.

The remaining samples had moderate ANC values of 20 to 34 kg H2SO4/t, and showed long lags,

with samples 14130 (Figure C4), 14206 (Figure C6) and 14567 (Figure C8) failing to drop below pH

4, and samples 14628 (Figure C9) and 14764 (Figure C12) having long lags of over 300 minutes,

indicating lags of several years before acid conditions develop.

Results indicate variable lag times from months to several years for PAF materials. Leach column

testing would be required to confirm these preliminary findings.

6.6 Acid Buffering Characteristic Curve (ABCC) Testing

Acid buffering characteristic curve (ABCC) testing was carried out on 25 selected samples to

evaluate the availability of the ANC measured.

The ABCC test involves slow titration of a sample with acid while measuring the solution pH. The

acid buffering of a sample to pH 4 can be used as an estimate of the proportion of readily available

ANC. Results are shown in Appendix C, Figures C13 to C29, with calcite, dolomite, ferroan

dolomite and siderite standard curves as reference. Calcite and dolomite readily dissolve in acid

and exhibit strongly buffered pH curves in the ABCC test, rapidly dropping once the ANC value is

reached. Siderite provides very poor acid buffering, reflected in a very steep pH curve in the ABCC

test. Ferroan dolomite has an acid buffering availability between siderite and dolomite.

The ABCC curves for 12 of the samples 14099 (Figure C28), 14144 (Figure C17), 14208 (Figure

C19), 14209 (Figure C26), 14230 (Figure C20), 14738 (Figure C29), 14767 (Figure C23), 14770

(Figure C27), 14722 (Figure C22), 14724 (Figure C24), 14726 (Figure C19) and 14731 (Figure C19)

show strong buffering similar to the calcite and dolomite standard curves, but with a variable

proportion of ready availability of 30% to 100%.

Samples 14115 (Figure C15), 14212 (Figure C14), 14687 (Figure C28), 14586 (Figure C25), 14590

(Figure C20), 14592 (Figure C15), 14628 (Figure C16), 14652 (Figure C13) and 14674 (Figure C21)



have profiles that plot close to the ferroan dolomite standard curve. The readily available ANC

portion ranges from 35% to 100% of the total ANC, with reaction rates likely to be slow.

Three samples, 14101 (Figure C18), 14240 (Figure C17) and 14764 (Figure C17), have profiles that

plot between ferroan dolomite and siderite standard curves, indicating slow reactivity, with the

readily available ANC portion ranging from 30% to 55%.

The remaining sample 14657 (Figure C14) has a sideritic profile, with a low portion of readily

available buffering at 15%.

Overall results show variable ANC reactivity and effectiveness, with no clear correlation with ANC

magnitude or rock unit, suggesting the presence of a number of different neutralising carbonate

phases. The total ANC measured in materials represented by the samples tested may

overestimate the effective ANC.

6.7 Carbon Speciation Testing

Total C testing was carried out on all samples and carbon speciation testing on 66 selected

samples for comparison with standard ANC (measured by titration) and ABCC results to assess

whether total C and/or carbonate C could be used as a proxy for ANC. Results are shown in Table

B1.

Figure 18 compares total C to carbonate C, with only two samples showing significantly lower

carbonate C compared to total C. Results indicate a low proportion of organic C, and hence total C

can be used as an indication of carbonate C in these samples.

Figure 19 compares the ANC estimated from total C with the standard titrated ANC, and Figure 20

is the same plot with an expanded scale. The plots show that although there is a general increase

in standard ANC with increasing total C ANC, there is considerable spread in the results, most

likely due to the presence of iron carbonates and dissolution of faster reacting silicates in the ANC

test.

Figure 21 compares total C ANC and standard ANC with the effective ANC indicated by ABCC

testing, with Figure 22 the same plot but rescaled. Results show that both total C ANC and the

standard ANC do not reliably reflect and mainly overestimate the effective ANC. Both total C ANC

and standard ANC results should be used with caution due to the likely presence of iron carbonate

and consequent partial ineffectiveness. Total C ANC could be used in routine testing, but an

ANC/MPA ratio of 2 should be applied as a factor of safety for NAF classifications in the absence of

other data.



Figure 18: Total C versus carbonate C.

Figure 19: ANC estimated from Total C versus standard ANC by titration.




Figure 21: ANC estimated from Total C and standard ANC by titration versus effective ANC from ABCC testing.




6.8 Sulphur Speciation

Sulphur speciation analysis was carried out on 30 selected samples, with results are presented in

Appendix B, Table B3. The chromium reducible sulphur (CRS) method provides an indication of

pyritic/pyrrhotitic S content, but will not recover sulphates (gypsum/anhydrite), jarosite or alunite.

Note that the pyritic S value should only be treated as a guide to the pyrite/pyrrhotite content in the

sample due to issues with repeatability in the chromium reducible sulphur (CRS) method1.

Most samples tested have high pyritic S values, with the acid generating proportion generally over

70%, showing that the total S values are a reasonable guide to the acid generating S content. Note

that recovery of chalcopyrite, galena and arsenopyrite in the CRS method is lower than pyrite (75%

to 85%2), and the apparent residual S not accounted for by CRS may reflect this partial sulphide

recovery rather than the presence of other S forms. Note also that generally the oxidised samples

had significant pyritic S, indicating residual sulphides in oxide zone materials. The only notable

exception was near surface sample 14076, which had low S of 0.3% and negligible pyritic S,

possibly jarosite.

1 Environmental Geochemistry International, Levay and Co. and ACeSSS, 2008. ACARP Project C15034:

Development of ARD Assessment for Coal Process Wastes, EGi Document No. 3207/817, July 2008.

www.acarp.com.au.

2 Schumann, R., Stewart, W., Miller, S., Kawashima, N., Li, J. and Smart, R., 2012. Acid–Base Accounting

Assessment of Mine Wastes Using the Chromium Reducible Sulfur Method, Science of the Total Environment

424 (2012) 289–296.

http://www.acarp.com.au/



Figure 23 is a plot of ICP S results from the assay database versus Leco total S values, with Figure

24 the same plot but rescaled. The results show (apart from 2 anomalous results) a strong 1:1

correlation up to approximately 2.5%S, with the ICP results showing slight variation from the Leco

S results above 2.5%S. The results suggest that ICP S results should be a suitable guide to the

acid forming S content in a sample.

Figure 23: ICP S versus Leco total S for waste rock and ore samples.




6.9 Multi-Element Analysis of Solids

Multi-element scans of solids were carried out on 30 selected waste rock and ore samples. Results

were compared to the median soil abundance (from Bowen, 19793) to highlight enriched elements.

The extent of enrichment is reported as the Geochemical Abundance Index (GAI), which relates

the actual concentration with an average or median abundance on a log 2 scale. The GAI is

expressed in integer increments where a GAI of 0 indicates the element is present at a

concentration similar to, or less than, median soil abundance; and a GAI of 6 indicates

approximately a 100-fold enrichment above median soil abundance. Generally, a GAI of 3 or

greater signifies enrichment that warrants further examination.

Results of multi-element analysis of solids are presented in Appendix B, Table B4, and the

corresponding GAI values are presented in Table B5.

Results show that samples are strongly enriched in Ag, Bi, Cu, and enriched in Be, Cd, Co, Cs, Mo,

Pb, S, Se, Tl, W and Zn, with enrichment increasing with proximity to ore. A number of samples

were also enriched in Fe and Mn, and individual samples were enriched in As, Hg, In, Li and Ta.

Results indicate these mine materials have elevated contents of a number of environmentally

significant metals/metalloids.

3 Bowen, H.J.M. (1979) Environmental Chemistry of the Elements. Academic Press, New York, p 36-37.



6.10 Composition of Water Extracts

Water extraction tests were carried out on the same 30 selected drill core samples at a solids:liquor

ratio of 1:5. The samples were rotated for 3 hours and allowed to sit overnight and filtered at

0.45µm. Water extracts were analysed for pH, EC, acidity/alkalinity and multi-elements. Results are

shown in Appendix B, Table B6, with % total S in solids provided for reference.

The pH of the extracts ranged from acidic to circum-neutral, at 3.3 to 8.6.

Most unoxidised ore samples and some of the mineralised and proximal waste rock samples had

acidic pH values of less than 5, elevated acidities, and associated high concentrations of dissolved

Al, Co, Cu, Fe, Mn, SO4 and Zn, slightly elevated Cd and Ni, and isolated elevated Pb. Many of the

extracts with circum-neutral pH showed slightly elevated to elevated Cu, Mn, SO4 and Zn,

particularly high S samples with greater than 2%S.

Results show that under acid conditions mobilisation of Al, Cd, Co, Cu, Fe, Mn, Ni, SO4 and Zn,

and possibly Pb, can be expected. The solubility of metals/metalloids will largely be determined by

pH and therefore control of acid generation will effectively control most metal leaching. Note that

some higher S (>1%S) NAF materials may be a source of salinity (SO4) and elevated Cu, Mn and

Zn with oxidation.

6.11 Sample Classification and Distribution of Geochemical Rock Types

The results and discussions presented above were used to classify samples as NAF, NAF high S

(NAF-HS), PAF, PAF-LC or UC in Table B1. PAF-LC samples are defined as having an acid

capacity of 5 kg H2SO4/t or less. NAF-HS samples are NAF samples with S greater than 1%S. All

samples with S values of less than or equal to 0.05%S were classified NAF due to the negligible

risk of acid formation.

Figure 25 shows the proportions (by sample count) of ARD classes for the major rock types.

Overall, NAF materials account for over 60% of the samples tested, with all felsic rock type

samples NAF, around 80% of oxide waste, transition waste, and fresh distal altered samples NAF,

around 70% of proximal samples NAF, and 45% of mineralised samples being NAF. This suggests

a high proportion of waste rock is likely to be NAF, and indicates significant flexibility in materials

segregation and handling.


2%S), indicating primary ore stockpiles, and residual primary ore zones in underground workings

and open pits will be a potential source of ARD. Oxide ore had much less PAF/PAF-LC as

expected, with over 80% of samples classified NAF. Transition ore samples were approximately

50% NAF.

The overall proportion of NAF-HS in both ore and waste rock is minor, accounting for only 9 of the

513 samples fully ARD tested.



Figure 25: Stacked bar chart showing proportions (by sample count) of ARD classes for each major rock type.

The ARD classifications were compared to key indicator parameters to identify possible simplified

criteria for site application.

Figure 26 is a box plot showing the distribution of Leco total S split into ARD classification classes.

The plot shows that total S alone could potentially be used for routine classification by applying a

0.4%S cut off to distinguish between NAF and NAF-HS/PAF-LC/PAF rock types. Note that a

≤ 0.4%S cut off is conservative in that it excludes all of the PAF-LC and PAF samples, but the

> 0.4%S range classifies 15% of the NAF samples as NAF-HS/PAF-LC/PAF.

A NAPP value was calculated using an ANC based on total C, and the distribution of NAPP (ANC

Total C) by ARD classification is shown in Figures 27. The plot shows that the NAPP (ANC Total C)

discriminates well between NAF and PAF-LC/PAF at cut off of 10 kg H2SO4/t, but includes most of

the NAF-HS samples. However, addition of S criteria, such that NAF is defined as sample with S ≤

1.0%S and a NAPP ≤ 10 kg H2SO4/t excludes the NAF-HS samples.

Figure 27 shows that the NAGpH is less discriminating between ARD classes. A cut off of 4.5

separates the NAF samples, but includes significant overlap of PAF samples.



Figure 26: Box plot showing the distribution of S split by ARD classification for waste rock and ore samples. Box plots have 5th, 10th, 25th, 50th (median), 75th, 90th and 95th percentiles.

Figure 27: Box plot showing the distribution of NAPP (ANC Total C) split by ARD classification for waste rock and ore samples. Box plots have 5th, 10th, 25th, 50th (median), 75th, 90th and 95th

percentiles marked.



Figure 28: Box plot showing the distribution of NAGpH split by ARD classification for waste rock and ore samples. Box plots have 5th, 10th, 25th, 50th (median), 75th, 90th and 95th percentiles

marked.

The NAF-HS samples account for only 9 of the 177 samples tested, and for the purposes of

materials segregation, it is suggested that NAF-HS materials be combined with PAF/PAF-LC

materials. Test work to date indicates that total S and NAPP (ANC Total C) are likely to be the best

choice of indicator parameter for site use, with NAGpH a potential check. Preliminary criteria for

these parameters are as follows, where PAF represents combined NAF-HS, PAF-LC and PAF

classes:

Total S Only Criteria

NAF: ≤ 0.4%S

PAF: > 0.4%S

NAPP (ANC Total C) Criteria

NAF: ≤ 10 kg H2SO4/t AND ≤ 1.0%S

PAF: > 10 kg H2SO4/t OR > 1.0%S

Where NAPP ANC Total = S x 30.6 – C x 81.7

Application of these criteria to the full geochemical data set (Table B1) has the following breakdown

by ARD class:

Criteria NAF PAF

Total S Only 53% 47%

NAPP (ANC Total C) 59% 41%



The breakdown shows that the S only criteria is only slightly less discriminating than the NAPP

(ANC Total C) criteria, and the need for additional C assays does not appear necessary. Note that

the ICP S data showed an almost identical S distribution between ARD classes as Figure 26, and

hence the S only criteria can be applied to the ICP S results in the Project assay database.

7.0 Geochemical Characterisation Results for Samples of Historic Mine Materials

Acid forming characteristics of the 22 historic mine material samples are presented in Appendix B,

Table B7.

The two sulphidic Bellbird samples with obvious white salts were confirmed acid producing, with

pH1:2 values of 3.8 and 4.0, and high salinity of 7 and 13 dS/m. TSF tailings 13105 had a slightly

acidic pH of 5.2 but only a slightly saline EC of 0.5 dS/m. The remaining samples had circum-

neutral pH of 6.5 to 8.6, with variable ECs of 0.1 to 8.6 dS/m and moderately saline to saline ECs

generally where salts were observed in the sampled material.

Total S varies from 0.02 to 7.36%S and ANC from 0 to 137 kg H2SO4/t. Figure 29 is an acid base

account plot for historic material samples. Most sample plot in the NAPP negative domain, with

ANC/MPA ratios greater than 2, indicating a high factor of safety. Four samples plot in the NAPP

positive domain; the two Bellbird samples, and one each of the Tailings/Milled ore and Green

Parrot Ore samples.

Figure 29: Acid-base account (ABA) plot for historic mine material samples.



Figure 30 is an ARD classification plot of the historic mine material samples. The same 4 samples

that plotted in the NAPP positive domain also plotted in the upper right hand uncertain domain, with

the remaining samples plotting in the NAF domain. The single addition NAGpH results are greater

than 4.5 in all samples, but the reaction was not likely to be complete in all the tests due to

elevated S and ANC.

Sequential NAG testing was carried out to 7 stages on selected samples to better determine the

acid potential. Results are presented in Appendix B, Table B8. Bellbird sample 13104 produced

acid leachate to pH 4.5 in the last 4 stages. This sample also produced acidities to pH 7 that were

much higher than the acidities to pH 4.5, most likely reflecting latent acidity released by dissolved

metals such as Cu and Zn into the NAG solution. None of the other samples produced NAGpH

values of less than 4.5 in any of the stages, but Bellbird sample 13103 and Green Parrot sample

13121 did release significant acidity to pH 7, again reflecting latent acidity. The results suggest that

apart from the two Bellbird samples, any acid produced from the other samples are likely to involve

a long lag time. Note that pH on water extracts for the two Bellbird samples confirms the materials

are already acid generating.

Figure 30: ARD classification plot showing NAGpH versus NAPP for historic mine material samples.

ABCC testing was carried out on 10 selected samples, and the profiles are presented in Appendix

C, Figures C30 to C35. The profile for TSF sample 13109 is similar to the dolomite curve, with the

readily available portion 70% of the total ANC. Tailings and Tailings/Milled Ore samples 13105,

13113 and 13117 have curves similar to the ferroan dolomite standard, with 85% to 100% readily

available but likely to be at slower reaction rates than dolomite. The remaining samples have

curves similar to siderite, suggesting poor reaction rates, with 3 to 35% readily available. Overall,



results suggest much of the ANC from these historic mine material samples is due to iron

carbonates and will have slow reaction rates and low availability.

Carbonate C results in Table B7 confirm that the vast majority of the carbon in these samples is in

carbonate form.

Sulphur speciation results for 10 selected historic waste rock samples are shown in Table B9. The

predicted proportion of acid generating S varies significantly from 2% to 80%. Most samples show

significant non acid sulphate, as expected from pyritic materials exposed to oxidation, with the two

Bellbird samples also having significant acid sulphate. The high proportion of other S forms is likely

to be due to lower recovery of chalcopyrite, galena and sphalerite in the CRS method compared to

pyrite.

Multi-element analysis was carried out on all 22 historic mine material samples. Multi-element

composition and geochemical abundance indices are presented in Appendix B, Table B10.

Samples were strongly enriched in Ag, Bi, Cu, Pb and Zn, enriched in Be, Cd, Hg, Mn, Mo, S, Se

and W, and slightly enriched in Ta and Tl. Isolated samples were enriched in As, Co and Sb.

All 22 historic mine material samples were also subjected to multi-element testing of water extracts,

with results shown in Appendix B, Table B12. The two Bellbird water extracts had acid pH and high

concentrations of acidity, SO4 and metals/metalloids. The water extract for TSF sample 13105 had

a slightly acidic pH of 5.2, and also showed elevated, but lower, concentrations of acidity, SO4 and

metals/metalloids. Water extracts for the remaining samples were circum-neutral, with generation

of slightly elevated and elevated SO4 and metals/metalloids in a number of samples.

Results of the geochemical testing discussed above show the following in regard to the various

historic mine materials:

• Bellbird - The two sulphidic Bellbird samples with obvious white salts were confirmed acid

producing. Samples were highly enriched in Cu, Ag and Bi, and enriched in As, Co, Mo,

Pb, Se and W, and liberated high concentrations of acidity, SO4, Al, Co, Cu, Mn, Ni, Zn.

These samples are a long term indicator of the elements of concern from primary Cu ore

and residual ore in workings and open pit if not managed.

• TSF - The 8 TSF tailings samples are all expected to be NAF, having moderate S of close

to 1% at the spigot discharge, but with S decreasing rapidly with distance from the spigot.

Although the tailings samples are NAF, they were highly enriched in Ag, Bi, Cd, Pb, Zn and

W, and enriched in Be, Cu, Hg, Mn, Mo and Pb. The samples close to the spigot liberated

high concentrations of Cu and Zn, with slightly elevated acidity, SO4, Cd, Co and Mn. The

samples away from the spigot generated some slightly elevated SO4 and Zn.

• Tailings/Milled Ore - Five samples were collected of what were thought to be either

tailings or milled ore located close to the process plant. All samples are expected to be

NAF. All samples were highly enriched in Ag, Bi, Cd, Cu, Pb, Zn and W, and enriched in

Be, Hg, Mn, Mo and Pb. Sample 13117 was a dark crust material scattered across the

storage area, and appeared to be primarily galena, which was confirmed with the multi

element analysis. Although this sample had high S of 7.4%, Pb multi-element results

indicates galena accounts for all S in the sample. Galena does not generate acidity when



oxidised, and hence sample 13117 is likely to be NAF, but it did generate elevated Mn, Pb

and Zn in water extracts. Sample 13113 had obvious white salts at surface, and water

extracts showed these were a mix of sulphate and chloride salts, with no significant

metal/metalloid mobilisation.

• Green Parrot Ore Stockpile - The Green Parrot ore stockpile had a mix of lead/zinc ore

with lesser copper ore, and the 7 samples collected all appear to be NAF. Samples 13121

and 13122 had elevated S of 1.3% and 4.6%S, respectively, but Zn and Pb contents

indicate this will be accounted for by sphalerite and galena, which are both non acid

generating sulphides. Samples 13121 and 13122 did generate elevated Zn, and slightly

elevated SO4, Cd, Mn and Pb.

Overall historic mine materials are metalliferous and show varying potential for generating acid,

saline, and metalliferous drainage, although on a localised scale. Reactivation of any of the old

facilities for storage of waste rock and tailings as part of the proposed Project should allow for re-

handling or incorporation of historic mine materials into management approaches that isolate them

from the receiving environment.

8.0 Geochemical Characterisation Results for Metallurgical Ore Feed and Tailings Samples

Acid forming characteristics of 10 metallurgical ore feed and equivalent tailings samples are

presented in Appendix B, Table B13. These samples were produced in a laboratory as part of

metallurgical investigations of the various ore types across site.

Marshall/Reward sulphide ore feed sample 15328 had a slightly acidic pH of 5.8 but a non-saline

EC of 0.14 dS/m. Green Parrot and Bellbird tailings samples 15336 and 15338 had circum-neutral

pH of 7.7 to 7.8 and moderately saline EC values of 0.9 to 1.0 dS/m. The remaining samples had

circum-neutral pH of 6.0 to 8.3 and non-saline to slightly saline ECs of less than 0.8 dS/m.

Total S varies from 0.07 to 7.03%S and ANC from 1 to 42 kg H2SO4/t. Figure 31 is an acid base

account plot for metallurgical samples. Most samples plot in the NAPP positive domain, with only

three samples having a NAPP of zero or less; two of the Green Parrot tailings and one of the

Marshall/Reward tailings. As expected, sulphur values for tailings are significantly lower than the

equivalent ore feeds. The ANC is generally low, with five samples showing moderate ANC greater

than 20 kg H2SO4/t.



Figure 31: Acid-base account (ABA) plot for metallurgical samples.

Figure 32 is an ARD classification plot for metallurgical samples. All Rockface ore and tailings

samples plot in the PAF domain, along with the Marshall/Reward sulphide ore and tailings

samples. The Marshall/Reward transitional tailings and both Green Parrot tailings samples plotted

in the NAF domain. The remaining samples plotted in the upper right hand uncertain domain. with

the remaining samples plotting in the NAF domain. As with other ore and mineralised samples,

most acidities to pH 7 were much higher than the acidities to pH 4.5, most likely reflecting latent

acidity released by dissolved metals such as Cu and Zn into the NAG solution.

Final ARD classifications for the metallurgical samples were made using results of specialised

testing carried out in Section 5. Results confirmed that all sulphide ore was PAF with high S. The

two transitional ore samples had lower S than other ore samples, and were the only ones classified

NAF. Although the tailings samples had lower S than the ore samples, results indicate that tailings

derived from sulphide ore will tend to be PAF. The only exception is the Green Parrot sulphide

tailings, which had very low S of 0.07%S. Both transition tailings were also classified NAF,

consistent with the ore samples.



Figure 32: ARD classification plot showing NAGpH versus NAPP for metallurgical samples.

Multi-element analysis was carried out on all 10 metallurgical tailings samples. Multi-element

composition and geochemical abundance indices are presented in Appendix B, Tables B14 and

B15. Samples were strongly enriched in Ag, Bi, Cu and W, enriched in Be, Cd, Co, Fe, Mn, Pb, S

Mo, Se, Tl and Zn, and slightly enriched in Cs and Mn. Isolated samples were enriched in Hg, Ta

and U.

The same 10 tailings samples were also subjected to multi-element testing of water extracts, with

results shown in Appendix B, Table B16. The Marshal/Reward Pb/Zn composite sample 15330 had

a circum-neutral pH but released elevated Mn and Zn and slightly elevated Cd, Co and SO4.

Slightly elevated SO4 was also released by the Green Parrot transitional tailings sample 15336 and

Bellbird sulphide tailings sample 15338, with the latter also releasing slightly elevated Cu.

Results show that sulphide ore and tailings samples are likely to be PAF, with transition ore and

tailings likely to be NAF. Water extracts indicate that elevated Cd, Co, SO4, Mn and Zn can be

expected from Pb/Zn tailings during the lag period, and SO4 and possibly Cu from other tailings

types.



9.0 Conclusions and Recommendations

Results show that the Project open cut and underground mine waste rock materials will comprise

mainly NAF material, accounting for 70% of the waste rock samples tested. Note that this

proportion does not reflect the true proportion of materials to be mined, and the overall proportion

of NAF is expected to be higher once an acid rock drainage (ARD) block model has been

completed, providing significant flexibility in materials segregation and handling. The smaller

portion of PAF (including PAF-LC and NAF-HS) materials occur mainly within a halo around the

sulphidic ore. Inspection of the core showed that PAF units in the waste rock should be readily

visually identified, with S a good discriminator of ARD rock types. Although testing focussed on

Rockface and Marshall/Reward projects, it is understood that Bellbird geology is similar, and

results and findings can be generally applied to Bellbird mine materials. A summary of ARD

potential by waste rock unit based on results to date is provided below:

Oxide Waste Rock NAF with occasional zones of PAF/PAF-LC

Transition Waste Rock NAF with occasional zones of PAF/PAF-LC

Distal NAF with occasional zones of PAF/PAF-LC

Proximal NAF with common zones of PAF/PAF-LC

Mineralised Mixed NAF and PAF/PAF-LC

Felsic NAF

Vein (Quartz/Tourmaline) NAF with common zones of PAF/PAF-LC


2%S), indicating primary ore stockpiles, and residual primary ore zones in underground workings

and open pits will be a potential source of ARD. Oxide ore had much less PAF/PAF-LC as

expected, with over 80% of samples classified NAF. Transition ore samples were approximately

50% NAF.

Specialised testing indicated the presence of iron carbonate, resulting in slow reaction rates and

variable ANC effectiveness. Despite this, kinetic NAG testing of PAF materials indicated significant

lag times before acid conditions develop after exposure to atmospheric oxidation, ranging from

months to several years, but leach column testing would be required to confirm these preliminary

findings. Longer lag times would provide flexibility in management of waste rock seepage during

any temporary storage or short term exposure during operations.

Sulphidic waste rock and ore materials show strong enrichment in a variety of metals/metalloids

including Ag, Bi, Be, Cd, Co, Cs, Cu, Mo, Pb, S, Se, Tl, W and Zn with enrichment increasing with

proximity to ore. A number of samples were also enriched in Fe and Mn, and individual samples

were enriched in As, Ag, As, Bi, Cd, Cu, Hg, Pb, Sb, Se, Tl and Zn.

Water extract testing indicates that the majority waste rock materials will not liberate significant

acid, salinity or metals/metalloids. However, under acid conditions mobilisation of Al, Cd, Co, Cu,

Fe, Mn, Ni, SO4 and Zn, and possibly Pb, can be expected. In addition, PAF materials during the

lag phase and some higher S (>1%S) NAF materials may generate salinity (SO4) and elevated Cu,

Mn and Zn with oxidation. The solubility of metals/metalloids will largely be determined by pH and

therefore control of acid generation will effectively control metal leaching.



Historic mine materials showed varying acid and salinity potential, but were generally metalliferous

and all generated leachates with some degree of elevated metals/metalloids in water extracts,

particularly Cd, Co, Cu, Mn, Ni, Pb and Zn.

Results suggest that tailings from sulphide ore samples will have moderate S values of around

1%S, but are still likely to be PAF. Tailings showed enrichment in a similar suite of

metals/metalloids as the waste rock and ore, including Ag, Bi, Be, Cd, Co, Cs, Cu, Fe, Mn, Pb, S

Mo, Se, Tl, W and Zn. Some mobilisation of Cd, Co, Cu, SO4, Mn and Zn can be expected during

the lag period.

Results indicate that the following preliminary segregation criteria based on total S only could be

used for routine classification:

NAF: ≤ 0.4%S

PAF: > 0.4%S

where PAF represents combined NAF-HS, PAF-LC and PAF classes

Results have the following implications for mine materials management:

• Most waste rock from pit and underground development is expected to be NAF and

environmentally benign, and will not require specific management for control of ARD.

Controlling ARD from the smaller portion of PAF (including PAF-LC and NAF-HS) should

be relatively straight forward, but will require selective handling and specific management

to prevent ARD into the long term. Long term options could include:

o in pit or underground disposal below recovery water table levels;

o selective underground disposal of PAF as part of paste backfill; or

o construction of an infiltration control cover system in-pit or ex-pit.

• Subaqueous disposal is the most secure option for controlling sulphide oxidation and ARD,

but the feasibility of this mechanism will depend on long term recovery groundwater and pit

water levels, and the volume of PAF mine materials this can accommodate.

• Placement of PAF underground along with cement backfill is preferred to surface dumping,

but will need to consider the reactivity of the sulphidic materials, and the transmissivity and

sensitivity of the receiving groundwater system.

• Most of the underground decline and other development not associated with ore extraction

would be carried out within distal units, and hence would be expected to be manly NAF,

but horizontal ore drives would become more sulphidic and PAF as the contact with the ore

zones are approached. Scheduling of underground waste rock should attempt to directly

utilise PAF in back fill and avoid bringing PAF materials to surface.

• Seepage and runoff from any surface dumped (or stockpiled) PAF waste rock materials

may require management during operations to mitigate any potential impacts on the

receiving environment. Contingency for treatment during operations may be required,

including dump surface limestone addition and/or blending to help delay onset of acid

drainage, and/or collection of seepage/runoff and treatment.



• Ore and low grade ore materials are likely to be mainly sulphidic and PAF, and represent a

potential source of ARD during operations. Ore and low grade ore stockpiles should be

managed to ensure capture and monitoring of any seepage/runoff, with contingency for

treatment if required. This will be particularly important for low grade materials expected to

be stockpiled for an extended period.

• The final pit voids will include a mix of NAF and PAF materials, with at least a portion likely

to generate acid (particularly exposures of fresh mineralised/residual ore materials), but

understanding the lag times, overall leaching characteristics, and final water quality will

require additional work. Pit water monitoring should be carried out during operations with

again contingency for treatment to help control impacts on the receiving environment. Pit

closure requirements for the pit will depend on the final distribution and leaching properties

of geochemical rock types in the final walls and floors.

• The stopes and drives close to the ore are likely to be sulphidic and PAF, and underground

seepage water from these zones is expected to be ultimately acidic, although cement

backfill may offset this to some degree. Potential impacts on the groundwater system from

underground water would need to be assessed.

• Dewatering of pits and underground workings is likely to require active management during

operations to ensure water quality of receiving drainage meets compliance. This could

entail water storage on site, water treatment, and/or controlled discharge during wet

periods at set dilution ratios.

• Tailings from fresh ore processing are expected to be PAF, and the proposed TSF will

require management to prevent ARD. The TSF will require a secure low permeability base

to prevent leaching of process water and oxidation products during operations, and is likely

to require an infiltration control cover system for closure. The potential for paste backfill of

tailings into underground workings should be assessed to help reduce the inventory of

tailings requiring surface management.

• Historic mine materials are metalliferous and show varying potential for generating acid,

saline, and metalliferous drainage, although on a localised scale. Given the small volume

of these materials, the uncertainty of the current effects from these materials on the

receiving environment, and the uncertainty in regard to the security of facilities constructed

to contain them, reactivation of any of the old facilities for storage of waste rock and tailings

as part of the proposed Project should allow for re-handling or incorporation of historic

mine materials into management approaches that demonstrate isolation from the receiving

environment.

The following programmes are recommended to better understand the geochemical properties of

mine materials and help determine appropriate materials management requirements for operations

and closure:

• Carry out kinetic leach column and batch water extraction testing to better understand the

leaching characteristics of key mine materials. Leach columns provide information on

leaching rates and geochemical evolution under atmospheric oxidation rates that can be

related to field conditions, and results can be used to model the water quality of mine

components during operations and at closure.



• Develop an initial S distribution model using the existing S database for all deposits to

better define the ARD potential of mine development materials using the preliminary S

criteria.

• Target further S testing to infill gaps in coverage for the S model, with additional

geochemical characterisation to confirm cut off criteria.

• Carry out specific geochemical assessment of Bellbird and other key deposits not directly

assessed to date.

• Further develop PAF waste rock management options, with priority on preferential

placement of PAF as underground backfill. This may include assessment of potential

underground void contaminant pathways, investigations into cover system designs,

seepage/runoff collection and treatment approaches, pit void backfilling options and

modelling of pit and underground recovery water levels.

• Clarify TSF base design and permeability, and investigate options for tailings infiltration

control cover systems, taking into account the effects of high intensity rainfall events.

• Assess the potential for paste backfill of tailings into underground workings to help reduce

the inventory of tailings requiring surface management

• Carry out preliminary water quality geochemical equilibrium modelling to better define the

likely impacts during operations and closure on surface and groundwater from the various

mine components with varying management options. This kinetic leach column data

recommended above would be a key input to the modelling.

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