Mara Rosa Metallurgical Testwork Report · Principal Consultant - Metallurgy . Coffey Mining Pty Ltd DOCUMENT INFORMATION Mara Rosa Pre-Feasibility Study – MINEWPER00525AC (10410)

Mara Rosa Metallurgical Testwork Report

Amarillo Gold Corporation

Mara Rosa Pre-Feasibility Study

MINEWPER00525AC (10410)

MINEWPER00525AC (10410)

Coffey Mining Pty Ltd ABN 52 065 481 209 1162 Hay Street, West Perth WA 6005 Australia PO Box 1671, West Perth WA 6872 Australia T (+61) (8) 9324 8800 F (+61) (8) 9324 8877 coffey.com

6 May 2011

Amarillo Gold Corporation Belo Horizonte, Minas Gerias BRAZIL Attention: Frank Baker

Dear

RE: Mara Rosa Metallurgical Testwork Report

Please find attached final report on the metallurgical testwork completed to date for the Pre-Feasibility Study, and recommended for the Feasibility Study. For and on behalf of Coffey Mining Pty Ltd Rod Smith Principal Consultant - Metallurgy

Coffey Mining Pty Ltd

DOCUMENT INFORMATION

Mara Rosa Pre-Feasibility Study – MINEWPER00525AC (10410) Mara Rosa Metallurgical Testwork Report – May 2011

Author(s): Rod Smith Principal Consultant - Metallurgy BSc (Met), MAusIMM

Chris Witt Consultant - Metallurgist BSc (Met), MAusIMM

Date: May 2011

Project Number: MINEWPER00525AC (10410)

Version / Status: Final

Path & File Name: F:\MINE\Projects\Coffey (BELO)\MINEWPER00525AC_10410_Amarillo Metallurgical Review\Report\CMWPr_525AC_MaraRosa_MetallurgicalTestwork_May2011_Final.docx

Print Date: Friday, 6 May 2011

Copies: Amarillo Gold Corporation (2)

Coffey Mining – Perth (1)

Document Change Control

Version Description (section(s) amended) Author(s) Date

Final Minor updates R Smith, C Witt 6 May 2011

Final Draft Formatted, geochem and FS testwork added R Smith, C Witt 5 May 2011

Rev 1 Update after cleint review R Smith, C Witt 29 April 2011

Rev 0 For client review R Smith, C Witt 25 April 2011

Document Review and Sign Off

Primary Author Rod Smith

Supervising Principal Linton Kirk

This document has been prepared for the exclusive use of Amarillo Gold Corporation (“Client”) on the basis of instructions, information and data supplied by them. No warranty or guarantee, whether express or implied, is made by Coffey Mining with respect to the completeness or accuracy of any aspect of this document and no party, other than the Client, is authorised to or should place any reliance whatsoever on the whole or any part or parts of the document. Coffey Mining does not undertake or accept any responsibility or liability in any way whatsoever to any person or entity in respect of the whole or any part or parts of this document, or any errors in or omissions from it, whether arising from negligence or any other basis in law whatsoever.



Table of Contents

EXECUTIVE SUMMARY ...........................................................................................................................i

1 Introduction ..................................................................................................................................3

2 Background ..................................................................................................................................4

3 Metallurgical Domaining ..............................................................................................................8

4 Mineralogy ....................................................................................................................................9

5 Sample Selection ....................................................................................................................... 11

6 Head Grade Analysis ................................................................................................................ 14

7 Testwork Programme ................................................................................................................ 15

8 Comminution Testwork Results and Interpretation .............................................................. 20

9 Metallurgical Testwork Results and Interpretation ................................................................ 22

9.1 Grind Size ....................................................................................................................... 23 9.2 Lime Demand and Effect of pH ...................................................................................... 25

9.3 Pre-Oxidation and Cyanidation Time Leach .................................................................. 27

9.4 Cyanidation Leach Residues .......................................................................................... 27

10 Geochemistry ............................................................................................................................ 28

10.1 Introduction ..................................................................................................................... 28 10.2 Samples .......................................................................................................................... 28

10.3 Testwork Programme ..................................................................................................... 28

10.4 Acid-Base Chemistry ...................................................................................................... 29 10.4.1 Maximum Potential Acidity (MPA) ......................................................................... 29 10.4.2 Acid Neutralisation Capacity (ANC) ...................................................................... 29 10.4.3 Net Acid Producing Potential (NAPP) ................................................................... 29 10.4.4 Net Acid Generating (NAG) ................................................................................... 29 10.4.5 Results Discussion ................................................................................................ 30

10.5 Multi Element Analysis ................................................................................................... 31 10.5.1 Tails Solids ............................................................................................................ 31

10.6 Conclusions .................................................................................................................... 33

11 Ancillary Testwork .................................................................................................................... 34

12 Key Design Criteria ................................................................................................................... 35

13 Process Flowsheet .................................................................................................................... 36

14 Further Testwork Recommendations ...................................................................................... 37



List of Tables Table 1 – Key Design Criteria for Mara Rosa Samples ii

Table 3_1 – Mineralogy Samples 8

Table 4_1 – Mineralogy Samples 10

Table 5_1 – Main Zone Composite Sample 12

Table 5_2 – Hanging Wall Zone Composite Sample 13

Table 6_1 – Head Grade Analysis of Composite Sample 14

Table 8_1 – Key Design Criteria for Comminution Testwork 20

Table 9_1 – Pre-Oxidation & Leach Design Criteria for Mara Rosa Samples 23

Table 9_2 – Pre-Oxidation and Cyanidation Time Leach Testwork 24

Table 10.4.5._1 – Acid Base Results Summary 30

Table 10.5.1_1 – Tails Multi Elemental Analysis – Main Composite 32

Table 10.5.1_2 – Tails Multi Elemental Analysis – Hanging Wall Composite 32

Table 12_1 – Design Criteria for Mara Rosa Samples 35

List of Figures Figure 5_1 – Schematic Plan View of Metallurgical Drillhole Locations 11

Figure 7_1 – Proposed Testwork Programme Flowsheet 17



Figure 9.1_1 – Grind Size Recovery Relationship at pH12 after 24 hours 25

Figure 9.2_1 – Main Composite – pH Demand 26

Figure 9.2_2 – Hanging Wall Composite Lime Demand 26

List of Appendices Appendix A – Metallurgical Drillhole Sample Details

Appendix B – Comminution Results

Appendix C – Pre-Oxidation & Cyanidation Leach Results

Appendix D – FS Metallurgical Testwork Program


Mara Rosa Pre-Feasibility Study – MINEWPER00525AC (10410) Page: i Mara Rosa Metallurgical Testwork Report – May 2011

EXECUTIVE SUMMARY

Metallurgical testwork was undertaken on representative samples from the Mara Rosa Project as part of the pre-feasibility study (PFS).

The Mara Rosa metallurgical samples comprised of a free milling component of gold (~75%) and a refractory component, which may be associated with sulphides as well as tellurides (~25%).

Gold recoveries in excess of 93% were readily achieved using conventional carbon in leach (CIL) technology with the addition of a simple pre-oxidation stage (3 agitated tanks) prior to the CIL circuit to account for the refractory gold telluride component in the mineralisation.

Cyanide consumption was low at 0.26kg/t, whilst lime requirements were slightly higher than average at 1.93kg/t. The slightly higher lime requirement is needed to raise the pH to 12 to accelerate the gold telluride oxidation process.

A review of the previous metallurgical testwork found many of the results to be inconsistent and less successful due to a lack of understanding of gold telluride chemistry, which although not overly complex, is rarely seen in practice with less than a handful of plants treating such materials worldwide.

Mineralisation containing gold tellurides simply needs to have an allowance for the oxidation of the gold telluride, using agitated tanks similar in size to the CIL tanks. The Mara Rosa mineralisation needs to be ground to a P80 size of 45µm prior to a pre-oxidation stage of 12 hours and a CIL stage of 24 hours. The overall plant residence time of 36 hours is strongly influenced by the relatively slow process of gold telluride oxidation. Given recent improvements in the understanding of aqueous sulphide and telluride oxidation, it is considered that there remains considerable scope for a reduction in the residence time of the plant with the completion of testwork to feasibility level.

There were three mineralogical domains identified; main, hanging wall and foot wall, although there were no significant differences between the domains from a metallurgical perspective. The samples tested were in the soft to medium range of competency in terms of milling and displayed no viscosity issues even at finer grind sizes. The abrasion index of the samples was in the medium to high range.

It is proposed that the process flowsheet would include primary crushing followed by secondary and tertiary crushing in closed circuit. Tertiary crushed material would then feed a primary mill and secondary mill utilising cyclone classification to achieve a P80 grind of approximately 45µm.

This material would be pre-oxidised at a pH of 12 for a period of 12 hours in agitated tanks and then leached under conventional CIL conditions for 24 hours during which an average of 93% of the gold would be dissolved and adsorbed onto activated carbon. The adsorbed gold would then be eluted using a convention desorption plant.

Tailings would be thickened to recover a significant proportion of the cyanide in the process solution, with the remaining thickened pulp detoxified to remove residual free cyanide prior to deposition in a tailings storage facility.


Mara Rosa Pre-Feasibility Study – MINEWPER00525AC (10410) Page: ii Mara Rosa Metallurgical Testwork Report – May 2011

Table 1 shows a summary of the key design criteria based on the metallurgical testwork results for the Mara Rosa samples.

Table 1 Mara Rosa Project

Key Design Criteria for Mara Rosa Samples

Criteria Unit Annual throughput tpa 2,500,000 Availability % 90.0% Instantaneous throughput tph 317 Bond rod mill work index kWh/t 13.4 Bond ball mill work index kWh/t 13.0 Abrasion index 0.3426 P80 grind size µm 45 pH set point 12.0 Pre-oxidation time hrs 12 Cyanidation leach time hrs 24 Cyanide consumption kg/t 0.26 Lime consumption kg/t 1.93 Thickener settling rate t/m2/h 0.50 Gold head grade g/t Au 1.47 Gold in residue (design) g/t Au 0.10 Gold recovery (design) % 93.2 Gold in residue (optimum) g/t Au 0.06 Gold recovery (optimum) % 95.9


Mara Rosa Pre-Feasibility Study – MINEWPER00525AC (10410) Page: 3 Mara Rosa Metallurgical Testwork Report – May 2011

1 INTRODUCTION

Coffey Mining were initially requested to undertake a review of the preliminary metallurgical testwork results and data from the Mara Rosa project, prior to being appointed to develop and manage a suitable metallurgical testwork programme for the project to a pre-feasibility level.

The Mara Rosa Project is located in Goias, Brazil and contains gold mineralisation associated with sulphides and tellurides. Geologically, it is a greenstone belt, shear hosted meso-thermal gold mineralized system of Neo-Proterozoic age.

The project encompasses approximately 60,000 hectares of exploration permits and 2,600 hectares of mining permits. Local infrastructure is excellent, with nearby access to Brazil's main North-South highway and close proximity to the national capital of Brasilia (320km) and the state capital, Goiania (350km). The main accumulation of gold within the Mara Rosa project is known as the Posse Deposit, which occurs in two main zones, Posse North and Posse South.

Prior to the Coffey Mining review, Amarillo had commissioned a preliminary metallurgical testwork study with the aim of establishing likely gold recovery and flowsheet options for processing mid to low grade Posse mineralisation. Previous higher grade (~3.5g/t Au) Posse mineralisation processed by WMC yielded recoveries of approximately 84% using standard, aerated CIL techniques.

The preliminary metallurgical testwork aimed to establish indicative gold recoveries that might be obtained using similar processing techniques to those previously used, but at a significantly lower resource grade of approximately 1.5g/t Au.

The Coffey Mining review noted that the gold mineralisation was associated with tellurides and sulphides, and that previous testwork programmes had failed to recognise the fundamental requirements for recovering gold from such minerals, hence the testwork recoveries tended to be inconsistent and less than optimal.

The recovery of gold from refractory sulphides is dependent on the association of the gold to the sulphide. If the gold is simply occluded (or locked within) the sulphide, then the recovery of such gold can be as simple as ensuring that the sulphides are ground fine enough to liberate the gold so that it can be dissolved in cyanide. If the gold is part of the atomic structure of the sulphide species, then it can only be recovered if the sulphide structure is broken down (generally oxidised) releasing the gold so that it can then be dissolved in cyanide.

However, for gold tellurides, it is imperative that the telluride be oxidised first, else the gold will remain insoluble in cyanide solutions. In a normal agitated leach tank, this may take up to 48 hours or more at an elevated pH of around 12. Only after the telluride has been oxidised can the gold be dissolved in cyanide.



2 BACKGROUND

A number of metallurgical testwork investigations have been conducted on the Mara Rosa mineralisation, primarily by WMC and Barrick.

Prior to the commissioning of the more recent testwork programmes, a number of preliminary cyanide leaching tests were completed on Posse core pulp samples at the metallurgical laboratory and pilot plant run by the Goias State mining entity Funmineral in the city of Goiania.

A number of mid to low grade samples were prepared from samples taken from 11 drillholes drilled within the Posse deposit with grades of 0.60, 0.76, 1.09 and 1.39g/t Au. The drill core had been previously pulped by Acme Labs in Goiania so that the samples had a P90 of approximately 75 microns. The results of the Funmineral tests indicated that an average gold recovery of 83% could be obtained from standard cyanidation bottle roll tests. It was suspected that the higher than expected gold recoveries might have been due to the natural oxidation of the sulphide materials during storage.

Amarillo commissioned Desenvolvimento de Processo Ltda to complete a new testwork programme in December 2009 to determine the likely metallurgical performance and gold recovery of the Posse sulphide mineralisation at a lower cutoff grade of 0.5g/t Au and a predicted run of mine gold grade of 1.48g/t Au. The testwork incorporated gravity and flotation concentration followed by cyanide leaching, including pre-oxidation treatment.

A total of 212kg of drill core intercept samples from the Posse mineralisation zone were selected and from these, six composite samples representing the main lithological domains and likely plant feeds were prepared.

Preliminary results from the cyanidation testwork yielded similar results to previous testwork in terms of lime demand, cyanide consumption and recovery. Under standard CIL conditions a consistent solid residue of between 0.40g/t – 0.60g/t Au was observed, which equates to a recovery of 60%-75% at a head grade of approximately 1.48g/t Au.

During the subsequent kinetic and pre-oxidation tests however, several anomalous results from one particular composite (Sample F) resulted in the suspension of the testwork. It is unclear whether the erroneous grades reported were the result of representivity issues relating to the splitting of the composite sample, or possible analytical error at the laboratory.

In order to further investigate the issue, the metallurgical laboratory subsequently re-homogenized the anomalous composite sample and re-assayed the material. The results returned results as expected, however, due to questions regarding the sample’s representivity, the testwork programme was halted.

Flotation testwork was carried out and achieved gold recoveries from 50% to 79% to a sulphide concentrate whilst preliminary Knelson centrifugal gravity concentration tests recovered less than 30% of the gold at a centrifugal force of 60G.



At this point, Amarillo provided Coffey Mining with summary reports of the historical testwork results for review. The majority of the testwork results related to mineralogical analysis, cyanide leaching and flotation recovery performance.

Mineralogical analysis indicated that the Posse mineralisation consisted predominately of pyrite with minor chalcopyrite, pyrrhotite and galena. Gold was present as both free grains and also associated with tellurides (predominately iron tellurides FeTe2). Tellurides occurred as isolated grains disseminated in the gangue or included in pyrite crystals. The main telluride minerals were calaverite (AuTe2), forming complex intergrowths with stibnite and native gold, and frohbergite. Sylvanite (AuAgTe4) was locally observed, associated with calaverite. The gold grain size was generally fine, ranging from 1µm to 10µm and occurred in various locations, including within silicates; composite with iron telluride; and/or at silicate grain boundaries.

Cyanide leach testing indicated that the Posse mineralisation contained a refractory component that was not readily cyanidable under normal conditions. Solid residues in the range of 0.4g/t Au – 0.6g/t Au were obtained in the majority of the Posse sulphide (deep) samples. This equated to a recovery of 60% - 75% at a 1.5g/t Au head grade. Some samples of Posse oxide, or shallow mineralisation, yielded significantly better recoveries in excess of 95% under standard leach conditions.

Kinetic leach tests indicated that the sulphide mineralisation contained a fast leaching, readily cyanidable portion, followed by an extremely slow leaching, semi-refractory portion. This was consistent with the mineralogical observation of both fine, free gold and gold/telluride/pyrite phases.

Diagnostic testwork conducted on the leach residues indicated that the majority of the non-leached gold was associated with the pyrite phase and to a lesser extent pyrrhotite and silicates, however, in the presence of tellurides, such diagnostic leach testing can often be flawed. It has been estimated that on average the mineralisation contained approximately 65% readily cyanidable gold and 35% refractory gold.

The diagnostic tests performed were unable to differentiate between the refractory sulphide and/or telluride components of the mineralisation. It was unclear if the refractory portion of gold was fine gold locked within pyrite, gold telluride species, gold/telluride locked in pyrite or a combination of all three.

A number of standard methods were investigated in order to increase gold recovery, including increasing cyanide concentration, increasing residence time, reducing the grind size, the addition of lead nitrate and pre-oxidation. Of these only the intensive pre-oxidation had any significant effect in increasing the gold recovery, yielding >80% @1.5g/t Au head grade, although results were inconsistent.

Preliminary flotation testwork by WMC indicated that >80% of the gold and >90% of the sulphur could be readily concentrated by flotation under typical conditions. The testwork performed involved simple single stage rougher tests. No locked-cycle, cleaning or reagent optimisations were performed.



WMC also operated a high grade CIL and heap leach operation processing the Posse mineralisation in the early 1990’s, with approximately 80,000oz Au being mined from the deposit at an average grade of 3.5g/t Au. Summary historical production records provided by Amarillo indicate that the standard CIL circuit returned an overall gold recovery of 84% at this higher head grade. This would appear to be consistent with the testwork above and indicates that the solid residues were in the order of 0.50g/t Au to 0.60g/t Au.

Coffey recommended that Amarillo undertake further testwork in a staged manner, with decisions for each subsequent stage based on the previous stage outcomes. This would enable design criteria and flow sheet options suitable for a pre-feasibility level of study to be established.

Although not an imperative to success, Coffey Mining recommended that the testwork be carried out at a commercial laboratory in Perth, Australia, where previous telluride testwork has been carried out with successful outcomes.

The presence of gold telluride is less common in operating gold projects possibly due to its refractory nature and the poor understanding of how to successfully process material that contain such mineralisation. In simple terms, gold tellurides are insoluble in cyanide unless they have first been oxidised prior to cyanidation. Some oxidation reactions for gold telluride are shown below.

AuTe2 + 2O2 + 2H2O ↔ Au + 2H2TeO3 (aqueous)

AuTe2 + 2O2 ↔ Au + 2TeO2 (gaseous – roasting)

In a normal agitated leach tank, the aqueous process may take 48 hours or more, even at elevated pH (>12), which increases the oxidation rate. Gold telluride that is not oxidised does not leach in cyanide and can therefore be the reason for reduced gold recovery in certain samples.

Based on the information provided by Coffey Mining, Amarillo instructed Desenvolvimento de Processo Ltda to complete some further metallurgical testwork with a focus on finer grinding of the samples and pre-oxidation of the gold telluride prior to the cyanidation step. A P80 grind of 38µm was targeted for each of the samples and then calcium hypochlorite at 5%w/v was used to pre-oxidise the samples over a 4 hour period prior to leaching. This methodology of finer grind, pre-oxidation and leaching generally achieved gold recoveries in excess of 90% and up to 98%.

Although the outcomes of the additional testwork were greatly improved in terms of gold recovery, the use of calcium hypochlorite (particularly at such concentrations) as a per-oxidant is impractical in a full scale plant. However, the important component of these testwork results was that they verified Coffey Mining’s opinion that the gold tellurides needed to be oxidised if they were to be soluble in cyanide.



As an aside, calcium hypochlorite is a very strong oxidant, but is also similar in price to sodium cyanide, which is used at around 0.030% to 0.050% w/v in most gold plants. Hence the use of calcium hypochlorite at levels of 5% w/v in the gold recovery process is not realistic in terms of process flow sheet development.

There are relatively few gold operations processing gold telluride, and as a consequence, there is relatively limited knowledge of the testwork requirements in many laboratories (and consultancies) worldwide.

An important component of the Mara Rosa testwork samples would likely be a comprehensive understanding of the mineralogy and nature of the cyanidation leach residues. The use of correct procedures and competent personnel would be vital in this area.

In addition to this, there have been several processes that have been developed and refined in more recent years that are potentially capable of providing an economic means for treatment of difficult refractory gold mineralisation, for example, the Albion process. For these reasons, it was strongly recommended that certain components of the testwork be carried out in specific laboratories rather than generic ones.

Amarillo decided to send approximately 316kg of samples representing the foot wall, main zone and hanging wall to Perth Australia, where laboratories were reasonably familiar with the requirements for processing difficult refractory gold ore samples.



3 METALLURGICAL DOMAINING

Discussions were held between Amarillo and Coffey Mining regarding the nature of the deposit from a mineralogical and metallurgical perspective. Based on the known geology and the preliminary mineralogical testwork that had been previously undertaken, it was decided that the most suitable mineralogical domaining for the proposed testwork programme would likely be based on the following:

Foot wall domain FW ~10% of the deposit

Main domain Main ~60% of the deposit

Hanging wall domain HW ~30% of the deposit

From a geological perspective, the deposit displayed reasonably good homogeneity and so the domaining as described above may not be required. Lithologically, the samples had been categorised by position (FW, Main, HW) and by colour (grey, pink, black).

The Coffey Mining review had identified that the most likely problematic components to the Mara Rosa deposit would be sulphide and / or telluride gold species. The identification of gold in sulphides and gold tellurides is extremely difficult from a mineralogical standpoint due to the very low levels that gold and telluride are present at. It is sometimes possible to undertake mineralogical analysis on such species, but this is generally on samples well defined by prior testwork and after concentration of the gold and telluride by methods such as superpanning.

For this reason, it was decided that an approach towards the non-sulphide mineralogy would be applied, that is, do the samples having different colours that represent the FW, Main and HW display different mineralogies on a macro scale. For example, is the mineralogical make-up of the MAIN samples similar when a black and pink sample are analysed.

Table 3_1 shows the six samples that were selected for mineralogical analysis. The aim of the mineralogical analysis was to identify the minerals present, describe any relevant characteristics regarding their mineral association with each other, identify where possible the liberation size of the key minerals and if telluride and / or gold species were identified, describe them.

Table3_1

Mara Rosa Project Mineralogy Samples

Hole ID Depth From (m)

Depth To (m) Domain Colour Au

(ppm) Te

(ppm)

MRP0001

154.28 155.21 MAIN Black 1.52 3.07

158.87 159.64 MAIN Grey 1.15 2.62

168.50 169.20 MAIN Pink 1.81 4.15

MRP0006 137.00 138.00 HW Grey 1.45 1.98

152.00 153.00 MAIN Grey 1.40 3.43

MRP0010 125.77 126.43 FW Black 1.08 2.50



4 MINERALOGY

Six samples of quartered diamond drill core were sent to Roger Townsend and Associates for mineralogical analysis.

The six samples represented various lithologies of the deposit based on the material location, that is, foot wall, main zone and hanging wall as well as the colour of the samples.

Binocular microscope examination suggested that in two of the samples, there was significant lithological variation, as is shown in the Table 4_1.

Two of the samples displayed varying gangue components within the same sample, although the effect of the variance in gangue component as observed is less likely to produce significant variability in either the physical or metallurgical properties of the samples.



Table 4_1 Mara Rosa Project

Summary of Mineralogical Analysis

MRP001 MRP006 1.52ppm 1.15ppm 1.84ppm 1.45ppm 1.40ppm 1.08ppm

Main Main Main HW Main FW Black Grey Pink Grey Grey Black

380243 380248 380259A 380259B 380393 380401 380474A 380474B Quartz Major Major Major Major Major Dom Major Plagioclase (Na,Ca)(Si,Al)4O8 Minor Major Dom Minor Major Dom Acc Acc K Feldspar ? Minor Trace Acc Major Acc Muscovite KAl2(Si3Al)O10(OH,F)2 Acc Acc Acc Acc Acc Acc Acc Biotite Acc Acc Acc Dom Acc Acc Acc Major Epidote Acc Minor Major Calcite Trace Minor Acc Clinoamphibole Acc A B B C D B A E

Table Key: Dom Dominant >50% Major Major 20% to 50% Minor Minor 10% to 20% Acc Accessory 1% to 10% Trace Trace <1%



5 SAMPLE SELECTION

Amarillo dispatched approximately 316kg of samples from 12 different diamond drillholes. The samples were inspected upon arrival to Australia to identify the nature of the respective samples (eg friable, competent) and to confirm that the proposed mineralogical domaining was not inappropriate.

The details of all of the individual diamond drillhole sample intervals including the gold and tellurium assays, gold to tellurium ratio and the weight of each sample are included in Appendix A.

Table 5_1 and Table 5_2 identify the individual drillhole intercepts that were selected to produce the two composite samples representing the main zone and the hanging wall zone.

Figure 5_1 shows the plan view of the metallurgical drillholes.

Figure5_1 Plan View of Metallurgical Drillhole Locations



Table 5_1

Mara Rosa Project Main Zone Composite Sample

Drillhole Depth From (m)

Depth To (m)

Weight (kg) Domain Colour Au

(ppm) Te

(ppm)

MRP0001

153.48 154.28 1.176 MAIN Black 2.01 3.39 154.28 155.21 1.214 MAIN Black 1.52 3.07 155.21 156.21 1.162 MAIN Black 1.78 4.37 156.21 157.07 0.838 MAIN Grey 0.94 3.23 157.07 157.96 0.964 MAIN Grey 3.61 4.67 157.96 158.87 1.040 MAIN Grey 0.65 1.29 158.87 159.64 0.786 MAIN Grey 1.15 2.62 159.64 160.57 1.194 MAIN Grey 0.98 4.39 160.57 161.53 1.142 MAIN Black 0.71 2.38 161.53 162.44 1.056 MAIN Black 1.37 3.23 162.44 163.15 0.880 MAIN Black 2.01 3.89 163.15 163.64 0.600 MAIN Black 1.95 4.21

MRP0002

127.00 128.00 1.188 MAIN Grey 0.88 1.40 128.00 129.00 0.996 MAIN Grey 0.76 1.93 129.00 130.00 1.112 MAIN Grey 1.02 2.39 130.00 131.00 1.028 MAIN Grey 4.99 7.51 131.00 132.00 1.138 MAIN Grey 1.01 2.65 132.00 133.00 1.140 MAIN Grey 1.88 3.14 133.00 134.00 1.126 MAIN Grey 4.37 7.38 134.00 135.00 0.982 MAIN Grey 0.74 2.18 135.00 135.75 0.792 MAIN Grey 0.79 2.01 135.75 136.40 0.706 MAIN Grey 1.83 2.85 137.00 138.00 0.988 MAIN Pink 0.51 1.25 138.00 139.00 0.974 MAIN Pink 0.50 1.31

MRP0003

147.06 147.66 0.728 MAIN Grey 1.80 3.02 147.66 148.27 0.834 MAIN Grey 0.71 1.82 149.06 149.88 1.008 MAIN Grey 4.22 5.58 149.88 150.31 0.524 MAIN Grey 0.76 3.10 150.31 150.85 0.624 MAIN Pink 0.76 1.95 152.45 153.00 0.622 MAIN Pink 0.65 1.34 153.00 154.00 1.210 MAIN Pink 3.13 4.29 154.00 155.00 1.074 MAIN Pink 1.62 2.75 155.00 155.94 1.142 MAIN Pink 4.83 6.66 155.94 156.77 1.020 MAIN Grey 1.97 4.17 156.77 157.25 0.546 MAIN Grey 0.55 2.16 157.25 157.88 0.816 MAIN Grey 2.15 4.04

MRP0009

131.00 132.00 1.126 MAIN Grey 0.82 2.05 132.00 133.00 1.148 MAIN Grey 1.55 2.47 133.00 134.00 1.144 MAIN Grey 2.66 5.62 134.00 135.00 1.182 MAIN Grey 2.75 4.90 135.00 136.00 1.070 MAIN Black 2.22 6.03 136.00 137.00 1.224 MAIN Black 0.76 1.51 137.00 138.00 1.230 MAIN Black 0.62 1.44 138.00 139.00 1.216 MAIN Black 0.68 1.17 139.00 140.00 1.234 MAIN Black 0.56 2.11 140.00 141.00 1.368 MAIN Grey 0.56 2.21 141.00 142.00 1.188 MAIN Grey 2.01 3.74 142.00 143.00 1.238 MAIN Grey 0.55 2.08

MRP0010

102.00 103.00 1.088 MAIN Black 1.44 2.81 103.00 104.06 1.290 MAIN Black 1.46 2.24 104.06 105.00 1.266 MAIN Grey 0.56 1.02 105.00 106.00 1.232 MAIN Black 1.16 2.21 106.00 107.00 1.304 MAIN Black 1.47 2.06 107.00 108.00 1.244 MAIN Grey 2.02 2.94 108.00 109.00 0.994 MAIN Grey 1.11 2.73 109.00 109.94 1.100 MAIN Black 1.12 2.75 109.94 110.55 0.750 MAIN Black 1.51 2.94 110.55 111.59 1.124 MAIN Black 1.16 2.73 111.59 112.49 1.014 MAIN Black 0.97 3.23 112.49 113.48 1.024 MAIN Black 0.53 2.06



Table 5_2

Mara Rosa Project Hanging Wall Zone Composite Sample


Depth To (m)


(ppm) Te

(ppm)

MRP0006

132.63 133.55 1.212 HW Black 0.58 0.62 133.55 134.50 1.070 HW Grey 0.80 1.99 134.50 135.35 1.058 HW Grey 1.19 2.20 135.35 136.00 0.764 HW Grey 1.96 2.20 136.00 137.00 1.206 HW Grey 0.51 1.03 137.00 138.00 1.170 HW Grey 1.45 1.98 138.00 139.00 1.088 HW Grey 0.85 1.44 139.00 140.00 1.110 HW Grey 0.48 1.10 140.00 141.00 1.244 HW Grey 2.93 5.27 141.00 142.00 1.248 HW Grey 0.52 1.86 145.00 146.00 1.090 HW Grey 0.70 1.95

MRP0011

285.00 287.00 2.442 HW Grey 0.76 1.75 292.00 293.00 1.094 HW Grey 1.22 15.93 294.00 295.00 1.150 HW Grey 0.53 1.72 295.00 296.00 1.030 HW Grey 0.92 2.73 296.00 297.00 1.152 HW Grey 1.09 2.47 298.00 299.00 1.272 HW Grey 0.73 2.07 299.00 300.00 1.160 HW Grey 0.76 2.12 300.00 301.00 1.172 HW Grey 1.74 3.55 301.00 302.00 1.174 HW Grey 1.79 4.05 302.00 303.00 1.182 HW Grey 3.94 4.87 303.00 304.00 1.236 HW Grey 1.31 2.57 304.00 305.00 1.096 HW Grey 1.40 3.39 305.00 306.00 1.220 HW Black 0.87 4.46 306.00 307.00 1.290 HW Black 1.75 16.92 307.00 308.00 1.084 HW Black 1.57 15.38 315.00 316.00 1.192 HW Grey 0.64 4.52 331.00 332.00 1.084 HW Grey 0.61 1.92

MRP0012

242.00 243.00 1.034 HW Black 0.70 0.95 245.00 246.00 1.170 HW Black 0.53 0.76 250.00 251.00 1.160 HW Black 2.31 2.12 256.00 257.00 1.146 HW Grey 0.61 1.02 258.00 259.18 1.300 HW Grey 0.79 1.30 269.00 270.00 1.086 HW Black 0.83 1.22 291.00 292.25 1.586 HW Black 0.56 0.91 293.00 294.00 1.238 HW Grey 0.84 2.24 296.00 297.00 1.164 HW Black 0.53 1.62

MRP0014

242.00 244.00 2.524 HW Black 0.74 2.02 252.00 254.00 2.448 HW Black 1.64 2.25 254.00 256.00 2.536 HW Black 2.84 4.71 256.00 258.00 2.340 HW Black 0.76 1.71 258.00 260.00 2.364 HW Black 0.55 1.43 260.00 262.00 2.275 HW Black 0.51 1.22 268.00 270.00 2.352 HW Black 0.64 1.29 285.00 287.00 2.374 HW Black 0.69 2.25 291.00 293.00 2.414 HW Black 0.54 1.92 293.00 294.35 1.632 HW Black 0.51 1.63 294.35 296.35 2.574 HW Black 1.16 1.63



6 HEAD GRADE ANALYSIS

Table 6_1 shows the details of the head grade analysis for the Main, Hanging Wall and Foot Wall composite samples.

Table 6_1

Mara Rosa Project Head Grade Analysis of Composite Sample

Analyte Unit Main Composite #1

Hanging Wall Composite #1

Foot Wall Composite

Au1 g/t 1.19 1.24 0.71 Au2 g/t 1.22 1.40 0.67 Ag g/t <0.3 <0.3 0.3 Al % 7.52 7.68 7.76 As ppm 20 10 20 Ba ppm 700 900 446 Be ppm 2.1 2.4 2.6 Bi ppm <10 <10 <10 CTOTAL % 0.21 0.36 0.15 CORGANIC % <0.03 <0.03 < 0.03 Ca % 2.20 2.60 1.78 Cd ppm <5 <5 <5 Co ppm 10 15 10 Cr ppm 50 90 40 Cu ppm 264 188 510 Fe % 3.08 3.38 3.12 Hg ppm 0.10 0.20 < 0.1 K % 2.40 3.00 1.72 Li ppm <5 10 5 Mg % 0.92 1.32 5740 Mn ppm 900 1000 505 Mo ppm 25 15 25 Na ppm 3 3 3.35 Ni ppm 40 50 45 P ppm 600 600 600 Pb ppm 14 18 45 STOTAL % 1.90 1.12 1.58 SSULPHIDE % 1.78 1.10 1.30 Sb ppm 11.6 1.6 0.3 SiO2 % 67.0 63.6 67.8 Sn ppm <50 <50 <50 Sr ppm 158 252 198 Te ppm 1.8 2.0 2.2 Th ppm 16.0 14.0 12 Ti ppm 3400 3400 5 U ppm 5.3 5.6 2.7 V ppm 66 80 58 Y ppm 28 24 28 Zn ppm 70 62 94 Zr ppm 221 219 195



7 TESTWORK PROGRAMME

The metallurgical testwork programme for the Mara Rosa composite samples was completed using a staged approach. This was primarily due to the historical testwork results, which had on occasions produced inconsistent results, largely due to a lack of understanding of gold telluride chemistry.

Although all three mineralogical domains were tested for their metallurgical characteristics, there was an initial focus on the main and hanging wall samples, as they represented the major component of the deposit and the mineralogical analysis did not identify any significant differences that would likely affect the metallurgical behaviour of the three nominated mineralogical domains.

The staged approach to the testwork programmes allowed for ongoing decisions to be made with respect to the necessity of all of the proposed testwork.

In summary, the proposed testwork programme was to include the following:

Sample Preparation:

Select individual samples for mineralogical analysis;

Main and hanging wall composite samples for testwork;

Foot wall composite sample for testwork.

Mineralogy:

Minerals present;

Mineral associations;

Liberation size for relevant minerals;

Gold and telluride deportment (if feasible).

Head grade determination of all three mineralogical domains.

Grind Determination:

At a P80 of 75µm and 45µm.

Lime Demand:

Lime required to achieve pH’s of 9.0, 9.5, 10.0, 10.5, 11.0, 11.5 and 12.0 at a P80 of 45µm.

Pre-oxidation and cyanidation time leach testwork:

24hrs and 72hrs pre-oxidation with cyanidation time leach testwork at 2, 4, 8, 18, 24 and 48hrs at 40%w/w solids, pH 12, DO >20ppm;

Assay leach residue.



Leach residue diagnostic analysis:

If Au in residue >0.10ppm Au, then complete.

Flotation testwork:

If Au in residue >0.10ppm Au, then complete if justified.

Optimisation testwork on pre-oxidation and cyanidation time leach (pending results).

Physical testwork:

Ai, Wi(ball), Wi(rod).

Geochemistry on tailings sample.

The details of the proposed Ammtec testwork programmes for the main, hanging wall and foot wall composite samples are shown in Figures 7_1 to 7_3.



Figure7_1 Proposed Testwork Programme Flowsheet









8 COMMINUTION TESTWORK RESULTS AND INTERPRETATION

The comminution testwork programme identified the abrasion and grinding characteristics of the main and hanging wall composite samples. The foot wall composite sample was not tested due to its low percentage contribution to the deposit.

The samples displayed a medium to high level of abrasiveness and were in the soft to medium range of competency with respect to grinding.

Table 8_1 shows the key design criteria for comminution based on the testwork results.


Key Design Criteria for Comminution Testwork

Test Unit Main Composite

Hanging Wall Composite

Ai Abrasion Index 0.3410 0.3426 Wi(rod) Bond rod mill work index kWhr/t 13.4 13.1 Wi(rod) Bond rod mill work index kWhr/t 12.9 13.0

Diamond drill core samples with a minimum diameter of 50mm were not available and hence unconfined compressive strength (UCS) and crushing work index (CWi) testwork were not completed.

The options of primary crushing / SAG milling versus three stage crushing / ball milling were considered with respect to the comminution testwork for pre-feasibility level.

Given the metallurgical need for a relatively fine grind and the consequent power requirement, as well as the lack of clayey material in the deposit, it was proposed that three stage crushing and ball milling would provide an improved economic outcome, particularly with respect to grinding power costs. For this reason, any additional physical testwork that would be required to progress the study to a more detailed level could be completed at that point in time.

Ideally, the UCS would have been determined during this testwork programme, however, the assumption for the design criteria is that it exceeds 100MPa and hence a crusher capable of reducing competent rock in the higher ranges of UCS has been proposed.

If SAG milling is to be considered at more detailed levels of study, then JKTech style testwork would be required.

The abrasion index for the main and hanging wall composite samples were 0.3410 and 0.3426 respectively. This places the samples in the medium to high range for abrasive properties. For reference purposes, 0.10 would be considered to be in the lower range, 0.25 in the medium range and 0.40 (equivalent to quartz) in the higher range.



The detailed results of the abrasion test are included in Appendix B.

The Bond rod mill work index for the main and hanging wall composite samples were 13.4kWhr/t and 13.1kWhr/t respectively.

The Bond ball mill work index for the main and hanging wall composite samples were 12.9kWhr/t and 13.0kWhr/t respectively.

These results place the samples in the softer to medium range of competency for grinding. Although the option of SAG milling has not been selected in the process flowsheet, the ratio of the rod:ball mill work indices would suggest that the samples are amenable to SAG milling. This is based on the fact that the rod:ball mill work index ratios are less than 1.25:1. This indicative outcome does not preclude the need for further detailed grindability testwork, should SAG milling be considered as part of the flowsheet in the future.

The detailed results of the Bond rod and ball mill tests are also included in Appendix B.



9 METALLURGICAL TESTWORK RESULTS AND INTERPRETATION

The metallurgical testwork results for the main, hanging wall and foot wall composite samples indicated that a leach residue of 0.10g/t Au or less could be readily achieved via a process flowsheet that included grinding to a P80 of 45µm, pre-oxidation over a period of 12hrs at a pH of 12 and leaching at conventional cyanide concentrations for a period of 24hrs.

Although percentage gold recoveries are displayed in all of the testwork results, these are invariably grade dependent in most gold deposits, and hence the real focus of the testwork was to gain an understanding of the nature of the non-recovered gold in the cyanidation leach residue.

If cyanidation leach residues of 0.10g/t Au or less could not be achieved, then detailed diagnostic testwork on the leach residues was planned. A leach residue of 0.10g/t Au or less was achieved for all three mineralogical domains.

In the case of the main and hanging wall domains, lower leach residues of 0.06g/t Au were achieved when the pre-oxidation and cyanidation leach times were extended to 72hrs and 48hrs respectively. The foot wall composite sample did not have extended pre-oxidation and cyanidation leach time testwork performed due to the good results achieved at lesser times and the lower contribution of this domain to the overall deposit.

The respective head grades for the main, hanging wall and footwall composite samples were 1.39g/t Au, 1.43g/t Au and 0.76g/t Au respectively, whilst the respective leach residue grades with 12hrs pre-oxidation and 24hrs cyanidation leaching were 0.10g/t Au, 0.09g/t Au and 0.10g/t Au, for equivalent gold recoveries of approximately 93% at a head grade of 1.47g/t Au.

The testwork indicated that under typical CIL conditions (24hrs @ pH 10) without pre-oxidation, leach residues of 0.26g/t Au and 0.53g/t Au were achieved, equating to gold recoveries of 64% and 82% for the main and hanging wall composite samples respectively.

This indicates that the effect of the gold tellurides in the different samples can differ somewhat and if not sufficiently oxidised, then the results may well be erratic and inconsistent, as was the case in much of the earlier testwork on the Mara Rosa deposit.

The parameter that has the most significant effect is the oxidation of the gold tellurides. There is minimal literature regarding the nature of gold telluride oxidation (as compared to other gold mineralisation) and hence the understanding of this subject has remained more of a practical one learnt in the few operations that treat such materials worldwide, including the Fimiston mine in Kalgoorlie operated by Kalgoorlie Consolidated Gold Mines (KCGM) that Coffey Mining is familiar with. More recent developments in refractory gold processing (Albion Process) has indicated that gold tellurides can be rapidly oxidised (in 2hrs to 4hrs) at temperatures in excess of 60°C and at a pH of 9.0 to 9.5. However, without a sufficient concentration of oxidising sulphides (for example from a flotation concentrate) to provide an autogenous heat source, it is impractical to achieve these pulp temperatures.



Beyond this, efficient methodologies, apart from conventional oxygenation, for oxidising the gold tellurides at ambient temperature are less understood. Given that the gold tellurides oxidise more rapidly at finer grind sizes, indicating that their oxidation is less time dependent but rather reliant on oxygen mass transfer, then it is highly likely that if efficient methods of oxygen transfer are applied, then the gold tellurides may be oxidised over shorter time intervals.

If this is the case and devices such as oxygen injectors, pipe reactors, etc, are applied, then leach residues of 0.06g/t Au would be achievable over time frames not dissimilar to conventional plants, that is, 24hrs oxidation and residence time.

Such residues equate to a percentage gold recovery of approximately 96% at a head grade of 1.47g/t Au.

The key design criteria from a metallurgical perspective for each of the mineralogical domains are shown in Table 9_1.

Table 9_1

Mara Rosa Project Pre-Oxidation & Leach Design Criteria for Mara Rosa Samples

Criteria Unit P80 grind size µm 45 pH set point 12.0 Pre-oxidation time hrs 12 Cyanidation leach time hrs 24 Cyanide consumption kg/t 0.26 Lime consumption kg/t 1.93 Gold head grade g/t Au 1.47 Gold in residue (design) g/t Au 0.10 Gold recovery (design) % 93.2 Gold in residue (optimum) g/t Au 0.06 Gold recovery (optimum) % 95.9

Table 9_2 shows a summary of the gold recoveries for different grinds, pH, pre-oxidation times and leach times. The details of the individual leach tests are included in Appendix C.

9.1 Grind Size

Pre-oxidation and cyanidation leach tests were initially conducted at a P80 grind size of 45µm. The relatively fine grind size was selected so as to afford the gold telluride species the best opportunity for complete oxidation within the pre-oxidation and cyanidation leach time frames.

The tests carried out at a P80 grind size of 45µm yielded good gold recoveries and so coarser P80 grind sizes of 53µm and 75µm were also tested.

The testwork results displayed a strong correlation between grind size and gold recovery, although this is less likely to be the result of gold liberation, as would normally be the case, but instead a dependency on the ability of the gold telluride particles to oxidise during the pre-oxidation and cyanidation leach stages.




Pre-Oxidation and Cyanidation Time Leach Testwork

Test Number Composite Sample P80 Pre Oxidation pH Au Head

Grade Au Leach Residue

Au Recovery CN kg/t

Lime kg/t @ 8hrs @ 18hrs @ 24hrs @ 48hrs

HS24241 Main 45 0hr 10.0 1.39 0.17 65.3 80.0 81.3 87.8 0.16 1.24 HS24243 Main 45 6hr 12.0 1.43 0.08 84.7 88.8 91.9 94.4 0.29 1.92 HS24245 Main 45 12hr 12.0 1.43 0.08 85.0 91.4 93.2 94.4 0.26 2.14 HS23865 Main 45 24hr 12.0 1.37 0.07 88.3 93.1 94.0 94.9 0.27 4.76 HS23867 Main 45 72hr 12.0 1.35 0.06 89.9 92.9 93.8 95.6 0.29 4.52 HS24247 Main 45 24hr 11.0 1.37 0.15 73.4 81.1 84.3 89.1 0.30 1.76 HS24251 Main 53 24hr 12.0 1.41 0.14 78.7 85.3 87.9 90.1 0.20 1.58 HS24249 Main 75 24hr 12.0 1.39 0.16 78.3 84.9 86.8 88.5 0.20 1.40 HS24242 Hanging Wall 45 0hr 10.0 1.59 0.35 53.6 63.5 66.7 78.0 0.21 0.42 HS24244 Hanging Wall 45 6hr 12.0 1.49 0.07 84.1 92.0 93.7 95.3 0.28 1.60 HS24246 Hanging Wall 45 12hr 12.0 1.42 0.07 90.6 92.5 93.4 95.1 0.21 1.78 HS23866 Hanging Wall 45 24hr 12.0 1.24 0.07 91.3 92.4 93.4 94.4 0.27 3.36 HS23868 Hanging Wall 45 72hr 12.0 1.29 0.06 91.4 93.4 94.4 95.3 0.26 3.16 HS24248 Hanging Wall 45 24hr 11.0 1.48 0.28 64.0 69.4 75.3 81.0 0.30 1.08 HS24252 Hanging Wall 53 24hr 12.0 1.57 0.10 75.8 85.1 87.5 93.6 0.20 1.64 HS24250 Hanging Wall 75 24hr 12.0 1.40 0.14 76.7 85.6 88.8 90.0 0.16 1.50 HS24680 Footwall 45 24hr 12.0 0.76 0.10 78.3 83.5 86.8 0.31 1.86



The results at a P80 grind size of 53µm and 75µm were still reasonable although gold recoveries decreased by between 2% and 4%.

Figure 9.1_1 shows the grind size – recovery relationship at pH 12 after 24 hours.

Figure 9.1_1 Grind Size Recovery Relationship at pH12 after 24 hours

Based on the testwork results, a P80 grind size of 45µm has been recommended, although it should be noted that this grind size is based on laboratory screening, whilst an actual plant would utilise hydrocyclones, which classify according to mass. The effect of this is that the minerals with higher specific gravities, such as sulphides and tellurides, would be ground finer due to their specific gravity and the consequent bimodal classification effect, meaning that a P80 grind size of 53µm would likely produce a P80 of 45µm for the sulphide and telluride particles.

9.2 Lime Demand and Effect of pH

The oxidation rate of gold tellurides is considerably slower at a pH of less than 12 and at lower pulp temperatures (<60oC). Although it is impractical to raise the temperature, the pH can be elevated by the addition of lime. The amount of lime required to raise the pH from neutral (7.0) to 9.0 and then to 12.0 at increments of 0.5 was measured.

To achieve and maintain a target pH of 12.0 for 12hrs pre-oxidation and 24hrs of cyanidation leach, 2.14kg/t, 1.78kg/t and 1.86kg/t of lime were required for the main, hanging wall and foot wall composite samples respectively.

88.0

89.0

90.0

91.0

92.0

93.0

94.0

95.0

96.0

40 45 50 55 60 65 70 75 80

Reco

very

(%)

Grind Size (um)

MAIN

HW



The lime demand results for the main and hanging wall samples are shown in Figure 9.2_1 and Figure 9.2_2 respectively.

Figure 9.2_1

Main Composite Lime Demand

Figure 9.2_2 Hanging Wall Composite Lime Demand

Good gold recoveries were achieved at the initial target pH of 12 and so some additional testwork was carried out at a pH of 11, however, the gold telluride oxidation rate decreased significantly affecting overall gold recovery.

7.0

7.5

8.0

8.5

9.0

9.5

10.0

10.5

11.0

11.5

12.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

pH

Lime Addition (Kg/t)

Lime Addition Vs pH

7.0

7.5

8.0

8.5

9.0

9.5

10.0

10.5

11.0

11.5

12.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

pH

Lime Addition (Kg/t)

Lime Addition Vs pH



9.3 Pre-Oxidation and Cyanidation Time Leach

The results of the pre-oxidation and cyanidation time leach are discussed together as the exact time required to oxidise the gold tellurides is difficult to ascertain and there is little doubt that the gold telluride oxidation process is continuing to occur through the cyanidation leach tests. Hence the separation of the pre-oxidation and cyanidation leach phases is somewhat academic and for the purposes of telluride oxidation, should be combined, whilst for the purposes of cyanidation leach, the important aspect is that non-telluride gold has sufficient time to be dissolved in the cyanide solution.

A number of time combinations were tested for the main and hanging wall composite samples. The aim was to test typical practical time frames as well as to provide ideal maximum time frames, where complete gold telluride oxidation and gold cyanide dissolution should have been possible.

9.4 Cyanidation Leach Residues

Detailed diagnostic analysis on the cyanidation leach residues was not required due to the low gold residue values that were achieved.



10 GEOCHEMISTRY

10.1 Introduction

Coffey were requested by Amarillo Gold to carry out geochemical testwork and analysis on the leached tailings samples derived from the Mara Rosa metallurgical testwork.

The testwork focussed on:

Acid formation potential through ANC, NAG, NAPP testing (definitions below).

Multi-element composition of the tailings solids.

The geochemistry testwork was carried on two samples of CIL residue derived from previous metallurgical testwork conducted at Ammtec Laboratories in Perth. The gold recovery testwork was conducted on a number of composites samples representing the dominant mineralogical lithologies present in the Mara Rosa deposit.

Two leach residue samples from the ‘Main’ and ‘Hanging Wall’ composites were selected for preliminary geochemical analysis as they form the majority of the mineralisation source. The two samples represent the tail or residue from the pre-oxidation and cyanidation process.

The results indicate that both material types were ‘potentially acid forming’ (PAF), particularly the ‘Main’ composite sample which was classified in the moderate to high range.

10.2 Samples

The residue samples used for geochemistry testwork were generated from gold leaching testwork that was part of the preliminary metallurgical investigation conducted on the Mara Rosa deposit. It is assumed that the metallurgical testwork was conducted on representative feed material and that the tails produced from the leaching testwork is indicative of the final tails that could be expected from an operating plant.

10.3 Testwork Programme

The testwork procedures employed for this study are based on standard geochemical characterisation methods. The testwork was completed by AMMTEC Ltd (AMMTEC) under the project number A13025.

The two samples selected were the leach residues from cyanidation testwork samples:

HS24243 Main Composite

HS24244 Hanging Wall Composite



10.4 Acid-Base Chemistry

10.4.1 Maximum Potential Acidity (MPA)

The MPA reflects the maximum amount of acid that is generated if all the sulphide sulphur in the sample is completely oxidised according to the following reaction:

FeS2 + 15/4O2 + 7/2H2O = Fe(OH)3 + 2 H2SO4

From the elemental analysis the sulphide sulphur grade of the residue samples were as follows:

Main Composite: 1.46% 44.7kg H2SO4 per tonne of mineralisation

Hanging Wall Composite: 0.82% 25.1kg H2SO4 per tonne of mineralisation

10.4.2 Acid Neutralisation Capacity (ANC)

In this test the sample is acidified with a known amount of hydrochloric acid which is then heated to ensure reaction completion. The calcium carbonate equivalent of the sample is obtained by determining the amount of unconsumed acid by titration with standardised sodium hydroxide.

The ANC results for the two tests were as follows:

Main Composite: 36.0kg H2SO4 per tonne of mineralisation

Hanging Wall Composite: 44.6kg H2SO4 per tonne of mineralisation

10.4.3 Net Acid Producing Potential (NAPP)

The NAPP is calculated from the corresponding MPA and ANC values as follows:

NAPP = MPA - ANC

The calculated NAPP for the Mara Rosa tails samples are indicated below. A negative value for NAPP indicates that no acid should be produced. The acid neutralising component or buffer potential is higher than the maximum amount of acid that could be produced:

Main Composite: = 44.7 – 36.0 = 8.7kg H2SO4 per tonne of mineralisation

Hanging Wall Composite: = 25.1 – 44.6 = -19.5kg H2SO4 per tonne of mineralisation

10.4.4 Net Acid Generating (NAG)

In this test the sample is placed under oxidising conditions to accelerate the sulphide oxidation. The resulting solution is then back titrated to measure the amount of acid that was produced.



The following results were obtained for the Mara Rosa Project samples:

Main Composite: 11.6kg H2SO4 per tonne of mineralisation

Hanging Wall Composite: -13.3kg H2SO4 per tonne of mineralisation

This is a physical test designed to validate the theoretical NAPP calculations above. It uses accelerated oxidation to simulate the environmental conditions that occur in a tails storage or waste dump environment over a long period of time.

10.4.5 Results Discussion

Table 10.4.5_1 presents a summary of the acid base testwork results.

Table 4.5_1

Mara Rosa Project Acid Base Results Summary

Parameter Units Main Hanging Wall Sulphide Sulphur % Sulphide Sulphur 1.46 0.82 MPA kg H2SO4 / tonne 44.7 25.1 ANC kg H2SO4 / tonne 36.0 44.6 NAPP kg H2SO4 / tonne 8.7 -19.5 NAG kg H2SO4 / tonne 11.6 -13.3 ANC/MPA ratio 0.81 1.78

The results above indicate the main wall composite has a relatively high potential for acid formation. This is largely due to the high sulphide sulphur content of 1.46%. The acid neutralising capacity of the material is also relatively high at 36.0kg H2SO4 per tonne of mineralisation however this is not enough to completely neutralise all the sulphuric acid that could form, hence the positive NAPP reading.

The footwall samples had a lower sulphide sulphur content resulting in a significantly lower MPA value of 25.1kg H2SO4 per tonne of mineralisation. In this case however the material had a very high buffering capacity with an ANC of 44.6kg H2SO4 per tonne of mineralisation. Hence the neutralisation capacity is higher than the potential acid formation which results in a negative NAPP value.

The net acid generation or NAG test resulted in a good correlation with the theoretical data with the Main sample producing 11.6kg H2SO4 per tonne of mineralisation and the Hanging Wall producing -13.3kg H2SO4 per tonne of mineralisation.

In recent years, research (especially estimation of reaction-rates for diverse sulphide/gangue mineral assemblages) and field-experience at mining operations world-wide have shown that the potential for acid mine drainage (AMD) production is very low for mineralised waste and tailings materials with ANC/MPA ratios greater than 2.0.



The acid forming potential (AFP) of a sample can be classified as either:

Non-Acid forming (NAF)

Potentially acid forming (PAF)

The classification criteria often used in mining operations worldwide are:

NAF: Sulphide Sulphur <0.3%, both a negative NAPP and an ANC/MPA ratio of ≥2.0

PAF: Sulphide Sulphur ≥0.3%, a positive NAPP or a negative NAPP value with an ANC/MPA ratio of <2.0

Based on the results obtained the Main composite would be classified as PAF and is in the moderate to high range for tailings materials. The high NAPP and the confirmatory NAG test indicate that this material is likely to generate a significant amount of acid in an oxidising environment such as tail facilities or waste dump.

The Hanging Wall sample appears to be more ‘benign’ mainly due to the lower sulphide sulphur content. Overall the material produced a negative NAPP value which was confirmed with the negative NAG result.

Whilst most indications point to the hanging wall material not being an acid producer, according to established guidelines, material with ANC/MPA ratios less than 2.0 are technically classified as ‘potentially acid forming’. In this case the ANC/MPA ratio is slightly low at 1.78, however based on the overall results it would appear that the risk of significant acid formation associated with this material is low.

10.5 Multi Element Analysis

10.5.1 Tails Solids

The multi-elemental analysis of the tailing samples are presented in Table 10.5.1_1 and 10.5.1_2 for the Main and Hanging Wall samples respectively, along with a comparison with the average crustal abundance of the earth and the Geochemical Abundance Index (GAI). The GAI is calculated from the ratio of the sample element content and the average crustal abundance.

A GAI greater than 3 usually signifies enrichment to a level that warrants further investigation. Element enrichments serve as a starting point in the assessment of potential concerns for element leaching and the production of toxic dust from dry exposed tailings in the storage facility.

Both samples are similar in elemental composition with the exception of antimony which is significantly higher in the hanging wall sample. Results indicate that both molybdenum and titanium may be enriched in both tails materials. Antimony is considered slightly enriched in the hanging wall sample.



Table 10.5.1_1 Mara Rosa Project

Tails Multi Elemental Analysis – Main Composite

Element Units Element Content Average Crustal Abundance (ACA)

Geochemical Abundance Index (GAI)

Al % 7.76% 8.20% 0 Ca % 2.10% 4.10% 0 Fe % 3.70% 4.10% 0 K % 2.33% 2.10% 0 Mg % 0.84% 2.30% 0 Na % 3.26% 2.30% 0 As ppm 10 1.5 2 Ba ppm 600 500 0 Cd ppm 0 0.11 0 Co ppm 40 20 0 Cr ppm 1100 100 2 Cu ppm 240 50 1 Hg ppm 0.1 0.05 0 Mn ppm 825 950 0 Mo ppm 120 1.5 5 Ni ppm 605 80 2 P ppm 700 1000 0 Pb ppm 10 14 0 Sb ppm 0.3 0.2 0 Se ppm 0 0.05 0 Sr ppm 156 370 0 Th ppm 14 12 0 Ti ppm 3400 0.6 6 U ppm 4.4 2.4 0 V ppm 74 160 0 Zn ppm 96 75 0

Table 10.5.1_2

Mara Rosa Project Tails Multi Elemental Analysis – Hanging Wall Composite

Element Units Element Content Average Crustal Abundance (ACA)

Geochemical Abundance Index (GAI)

Al % 7.84% 8.20% 0 Ca % 2.61% 4.10% 0 Fe % 3.98% 4.10% 0 K % 3.03% 2.10% 0 Mg % 1.44% 2.30% 0 Na % 3.46% 2.30% 0 As ppm 10.00 1.5 2 Ba ppm 1200 500 0 Cd ppm 0 0.11 0 Co ppm 40 20 0 Cr ppm 1100 100 2 Cu ppm 180 50 1 Hg ppm 0.2 0.05 1 Mn ppm 985 950 0 Mo ppm 90 1.5 5 Ni ppm 565 80 2 P ppm 700 1000 0 Pb ppm 15 14 0 Sb ppm 5.9 0.2 4 Se ppm 0 0.05 0 Sr ppm 246 370 0 Th ppm 12 12 0 Ti ppm 3400 0.6 6 U ppm 4 2.4 0 V ppm 88 160 0 Zn ppm 86 75 0



Enriched minerals are only considered to be problematic if they are soluble and may potentially be leached in the tails environment. Leaching and mobilisation of the metals may occur under acid conditions that can results from acid mine drainage environments.

Molybdenum and titanium are not considered problematic and will typically form stable oxides in a tails environment. Antimony is relatively stable and forms various salts and is not typically reactive in dilute acidic or alkali environments. Antimony is toxic however and could potentially become problematic in the form of dust generated from a dry tails facility for example.

10.6 Conclusions

Based on the preliminary testwork results obtained in this study it would appear that the risk of significant acid formation associated with the main composite material from the Mara Rosa deposit is relatively high. The hanging wall material which forms the other major component of the mineralisation however was relatively benign.

Both material types would be classified as PAF according to the industry standard guidelines however the hanging wall material is considered a low risk in terms of acid production potential.

Further investigation is required in order to determine a suitable tails management strategy in order to mitigate the potential acid formation in a tails facility. The management plan could range from simply blending the high and low acid sources to minimise the risk, to engineering solutions incorporated into the process plant and tails facility designs.

It is also recommended that samples of the Mara Rosa waste rock material be sent for geochemical testing to assess the potential for acid formation in waste dumps.

The elemental results indicated that a titanium and molybdenum metals were enriched in both of the residue samples however these are relatively stable and not considered problematic in a tails environment. The hanging wall material had significantly higher levels of antimony than the main composite sample which can be toxic and hence problematic, particularly in the form of dust that can be generated from dried tailings. The antimony content is however based on one analysis and further testwork would be required to confirm the result.



11 ANCILLARY TESTWORK

No detailed ancillary testwork was undertaken at this stage, although the following comments are relevant to the progression to more detailed levels of study.

Site Water

The testwork was completed using Perth tap water. The effect of this is considered negligible as the site water is of a high quality and contains no deleterious elements or minerals that would affect the gold recovery for the proposed process flowsheet. It should be noted that site water analysis have been completed as a part of the environmental baseline studies.

Settling / Thickening

Settling / thickening testwork was not completed at this point and would not be expected to be an issue. It is proposed that a thickener precede the cyanide detoxification step, so as to recover cyanide and minimise the detoxification requirement. Given the fresh non viscous nature of the deposit, a conservative settling rate of 0.50t/m²/h has been applied for the thickener design. Despite this, such testwork should be completed as part of the feasibility stage of testwork.

Pulp Viscosity

The samples displayed no viscosity issues during the leach testwork and hence agitator design is not considered an issue even at a P80 grind of 45µm. Despite this, such testwork should be completed as part of the feasibility stage of testwork.



12 KEY DESIGN CRITERIA

The summary key design criteria is shown in Table 12_1.


Design Criteria for Mara Rosa Samples

Criteria Unit Annual throughput tpa 2,500,000 Availability % 90.0% Instantaneous throughput tph 317 Bond rod mill work index kWh/t 13.4 Bond ball mill work index kWh/t 13.0 Abrasion index 0.3426 P80 grind size µm 45 pH set point 12.0 Pre-oxidation time hrs 12 Cyanidation leach time hrs 24 Cyanide consumption kg/t 0.26 Lime consumption kg/t 1.93 Thickener settling rate t/m²/h 0.50 Gold head grade g/t Au 1.47 Gold in residue (design) g/t Au 0.10 Gold recovery (design) % 93.2 Gold in residue (optimum) g/t Au 0.06 Gold recovery (optimum) % 95.9



13 PROCESS FLOWSHEET

The Mara Rosa metallurgical samples were comprised of a free milling component of gold and a refractory component which may be associated with sulphides as well as tellurides.

The gold can be recovered using conventional CIL techniques, albeit with a requirement for finer grinding and pre-oxidation prior to leaching.

It is proposed that the mineralisation would undergo primary crushing followed by secondary and tertiary crushing in closed circuit. Tertiary crushed material would then feed a primary mill and secondary mill utilising cyclone classification to achieve a P80 grind of approximately 45µm.

This material would be pre-oxidised at a pH of 12 for a period of 12 hours in agitated tanks and then leached under conventional CIL conditions for 24 hours during which an average of 93% of the gold would be dissolved and adsorbed onto activated carbon. The adsorbed gold would then be eluted using a conventional desorption plant.

Tailings would be thickened to recover a significant proportion of the process solution (pH 12 and CN 0.015%), with the remaining thickened pulp detoxified to remove residual free cyanide prior to deposition in a tailings storage facility.

There is considerable scope to improve the pre-oxidation stage of the process, which currently accounts for 12 hours of agitated tank residence time. This may be achieved by oxygen injectors, pipe reactors, or other innovative means.



14 FURTHER TESTWORK RECOMMENDATIONS

Further testwork is deemed necessary assuming the project proceeds to a feasibility level of study. The testwork required at this stage would need to include variability testwork, as well as confirmatory composite testwork and optimisation testwork on the grind versus pre-oxidation characteristics of the mineralisation.

In addition to this, ancillary testwork requirements as discussed in Section 11 would need to be completed.

The details of the required testwork programme are included in Appendix D.

Appendix A Metallurgical Drillhole Sample Details

Appendix A – Metallurgical Drillhole Sample Details Page: 1

Table A_1

Mara Rosa Project

Details of Metallurgical Drillhole Intercepts


Depth To (m)


(ppm) Te

(ppm) Au:Te Ratio

MRP0001 85.68 86.37 0.916 WST Black 0.88 1.47 0.60 MRP0001 138.79 139.68 1.026 HW Gray 0.82 1.96 0.42 MRP0001 140.50 141.13 0.818 HW Black 0.61 0.89 0.68 MRP0001 144.00 144.82 0.984 MAIN Gray 1.38 1.52 0.91 MRP0001 147.00 147.42 0.454 MAIN Pink 0.58 0.89 0.65 MRP0001 147.42 148.03 0.700 MAIN Black 0.80 1.10 0.73 MRP0001 148.03 148.71 0.774 MAIN Black 0.57 1.40 0.40 MRP0001 148.71 149.39 0.864 MAIN Gray 0.75 1.50 0.50 MRP0001 150.09 151.18 1.050 MAIN Gray 2.65 4.78 0.56 MRP0001 151.18 152.36 1.104 MAIN Gray 4.36 5.99 0.73 MRP0001 153.48 154.28 1.176 MAIN Black 2.01 3.39 0.59 MRP0001 154.28 155.21 1.214 MAIN Black 1.52 3.07 0.49 MRP0001 155.21 156.21 1.162 MAIN Black 1.78 4.37 0.41 MRP0001 156.21 157.07 0.838 MAIN Gray 0.94 3.23 0.29 MRP0001 157.07 157.96 0.964 MAIN Gray 3.61 4.67 0.77 MRP0001 157.96 158.87 1.040 MAIN Gray 0.65 1.29 0.50 MRP0001 158.87 159.64 0.786 MAIN Gray 1.15 2.62 0.44 MRP0001 159.64 160.57 1.194 MAIN Gray 0.98 4.39 0.22 MRP0001 160.57 161.53 1.142 MAIN Black 0.71 2.38 0.30 MRP0001 161.53 162.44 1.056 MAIN Black 1.37 3.23 0.42 MRP0001 162.44 163.15 0.880 MAIN Black 2.01 3.89 0.52 MRP0001 163.15 163.64 0.600 MAIN Black 1.95 4.21 0.46 MRP0001 164.58 165.51 1.130 MAIN Black 0.99 2.35 0.42 MRP0001 167.21 167.96 0.818 MAIN Black 1.07 3.25 0.33 MRP0001 167.96 168.50 0.678 MAIN Black 0.34 1.17 0.29 MRP0001 168.50 169.20 0.856 MAIN Pink 1.81 4.15 0.44 MRP0001 169.20 169.88 0.810 MAIN Gray 0.95 2.48 0.38 MRP0001 169.88 170.46 0.796 MAIN Black 2.19 3.80 0.58 MRP0001 170.46 170.94 0.574 MAIN Black 1.70 3.25 0.52 MRP0001 170.94 171.63 0.794 MAIN Black 2.85 5.13 0.56 MRP0001 174.44 175.32 1.074 MAIN Gray 0.55 3.42 0.16 MRP0001 175.32 176.31 1.076 MAIN Gray 0.74 2.17 0.34 MRP0001 179.03 180.00 1.194 FW Gray 0.53 2.43 0.22


Table A_2

Mara Rosa Project



Depth To (m)


(ppm) Te

(ppm) Au:Te Ratio

MRP0002 27.00 28.00 1.032 WST Black 0.81 1.26 0.64 MRP0002 97.00 98.00 1.088 HW Black 4.71 6.38 0.74 MRP0002 98.00 99.00 1.102 HW Black 3.44 5.50 0.63 MRP0002 99.00 100.00 1.176 HW Black 1.81 3.91 0.46 MRP0002 101.00 102.00 1.110 HW Gray 0.52 2.02 0.26 MRP0002 102.00 103.00 1.100 HW Black 0.73 1.69 0.43 MRP0002 107.00 108.00 1.084 HW Gray 0.51 1.27 0.40 MRP0002 108.00 109.00 1.044 HW Gray 0.90 1.47 0.61 MRP0002 110.00 111.00 1.078 HW Gray 0.67 1.27 0.53 MRP0002 111.00 112.00 1.128 HW Gray 0.51 0.96 0.53 MRP0002 113.00 114.00 1.094 HW Gray 3.33 4.35 0.77 MRP0002 119.00 120.00 1.134 MAIN Black 4.45 4.33 1.03 MRP0002 121.00 122.00 1.042 MAIN Black 0.70 1.45 0.48 MRP0002 123.00 124.00 1.150 MAIN Gray 0.72 1.70 0.42 MRP0002 124.00 125.00 1.104 MAIN Gray 0.67 1.60 0.42 MRP0002 125.00 126.00 1.096 MAIN Gray 1.90 2.82 0.67 MRP0002 126.00 127.00 1.102 MAIN Gray 2.09 3.73 0.56 MRP0002 127.00 128.00 1.188 MAIN Gray 0.88 1.40 0.63 MRP0002 128.00 129.00 0.996 MAIN Gray 0.76 1.93 0.39 MRP0002 129.00 130.00 1.112 MAIN Gray 1.02 2.39 0.43 MRP0002 130.00 131.00 1.028 MAIN Gray 4.99 7.51 0.66 MRP0002 131.00 132.00 1.138 MAIN Gray 1.01 2.65 0.38 MRP0002 132.00 133.00 1.140 MAIN Gray 1.88 3.14 0.60 MRP0002 133.00 134.00 1.126 MAIN Gray 4.37 7.38 0.59 MRP0002 134.00 135.00 0.982 MAIN Gray 0.74 2.18 0.34 MRP0002 135.00 135.75 0.792 MAIN Gray 0.79 2.01 0.40 MRP0002 135.75 136.40 0.706 MAIN Gray 1.83 2.85 0.64 MRP0002 137.00 138.00 0.988 MAIN Pink 0.51 1.25 0.40 MRP0002 138.00 139.00 0.974 MAIN Pink 0.50 1.31 0.38 MRP0002 139.84 140.51 0.720 MAIN Black 1.06 2.81 0.38 MRP0002 140.51 141.00 0.540 MAIN Black 1.67 2.77 0.60 MRP0002 141.00 142.00 1.190 MAIN Gray 0.76 2.10 0.36 MRP0002 142.00 142.37 0.398 MAIN Gray 2.56 5.01 0.51 MRP0002 142.37 143.00 0.712 MAIN Gray 0.87 3.08 0.28 MRP0002 143.00 144.00 1.090 MAIN Gray 2.57 5.24 0.49 MRP0002 144.00 145.00 0.972 MAIN Gray 0.80 2.44 0.33 MRP0002 145.00 146.00 1.036 MAIN Gray 0.52 2.71 0.19 MRP0002 147.00 148.00 1.150 MAIN Gray 0.73 2.92 0.25 MRP0002 151.00 152.00 1.042 MAIN Gray 0.73 2.86 0.26 MRP0002 152.00 153.00 1.144 MAIN Black 1.51 2.85 0.53 MRP0002 153.00 154.00 1.108 MAIN Gray 3.73 6.63 0.56 MRP0002 155.00 156.00 1.114 FW Gray 0.55 2.46 0.22 MRP0002 156.00 157.00 0.980 FW Gray 0.52 2.20 0.23


Table A_3

Mara Rosa Project



Depth To (m)


(ppm) Te

(ppm) Au:Te Ratio

MRP0003 96.77 97.39 0.776 WST Gray 1.45 2.36 0.61 MRP0003 103.59 104.10 0.586 WST Gray 0.85 1.84 0.46 MRP0003 104.10 104.75 0.842 WST Gray 1.74 2.49 0.70 MRP0003 105.95 106.96 1.274 HW Gray 4.74 8.27 0.57 MRP0003 114.00 115.00 1.222 HW Gray 1.04 1.67 0.62 MRP0003 115.00 116.00 1.138 HW Gray 0.66 1.66 0.40 MRP0003 122.47 123.05 0.820 HW Gray 0.63 1.39 0.46 MRP0003 128.17 129.00 1.142 HW Gray 0.52 1.15 0.45 MRP0003 136.13 136.96 1.060 HW Gray 0.60 1.35 0.45 MRP0003 141.16 141.82 0.868 HW Gray 0.62 1.11 0.56 MRP0003 145.21 145.67 0.576 MAIN Gray 0.65 1.21 0.53 MRP0003 146.28 147.06 1.016 MAIN Gray 2.72 4.41 0.62 MRP0003 147.06 147.66 0.728 MAIN Gray 1.80 3.02 0.60 MRP0003 147.66 148.27 0.834 MAIN Gray 0.71 1.82 0.39 MRP0003 149.06 149.88 1.008 MAIN Gray 4.22 5.58 0.76 MRP0003 149.88 150.31 0.524 MAIN Gray 0.76 3.10 0.25 MRP0003 150.31 150.85 0.624 MAIN Pink 0.76 1.95 0.39 MRP0003 152.45 153.00 0.622 MAIN Pink 0.65 1.34 0.48 MRP0003 153.00 154.00 1.210 MAIN Pink 3.13 4.29 0.73 MRP0003 154.00 155.00 1.074 MAIN Pink 1.62 2.75 0.59 MRP0003 155.00 155.94 1.142 MAIN Pink 4.83 6.66 0.72 MRP0003 155.94 156.77 1.020 MAIN Gray 1.97 4.17 0.47 MRP0003 156.77 157.25 0.546 MAIN Gray 0.55 2.16 0.25 MRP0003 157.25 157.88 0.816 MAIN Gray 2.15 4.04 0.53 MRP0003 157.88 158.40 0.600 MAIN Gray 1.50 4.80 0.31 MRP0003 159.20 159.65 0.598 MAIN Gray 0.88 1.88 0.47 MRP0003 159.65 160.32 0.826 MAIN Gray 0.60 1.49 0.40 MRP0003 160.32 161.24 1.136 MAIN Gray 0.72 1.88 0.38 MRP0003 162.78 163.38 0.776 FW Gray 0.56 2.31 0.24

Table A_4

Mara Rosa Project



Depth To (m)


(ppm) Te

(ppm) Au:Te Ratio

MRP0004 1.32 2.05 0.805 WST Gray 0.98 1.30 0.75 MRP0004 2.05 2.51 0.584 WST Gray 1.30 1.40 0.93 MRP0004 61.53 62.00 0.458 WST Black 1.11 3.77 0.29 MRP0004 62.00 63.00 1.200 WST Black 0.93 1.81 0.51 MRP0004 70.00 71.00 1.114 WST Black 0.63 1.44 0.44 MRP0004 83.00 84.00 0.990 HW Black 0.90 1.49 0.60 MRP0004 93.12 93.73 0.658 HW Pink 0.63 0.89 0.70 MRP0004 93.73 94.20 0.612 HW Black 2.15 2.40 0.90 MRP0004 94.20 95.00 0.878 HW Gray 0.71 0.67 1.07 MRP0004 98.00 99.00 1.344 MAIN Gray 1.51 2.30 0.65 MRP0004 99.00 100.00 1.382 MAIN Gray 1.40 3.04 0.46 MRP0004 104.00 105.00 1.292 MAIN Gray 0.55 1.71 0.32 MRP0004 105.00 106.00 1.268 MAIN Gray 1.04 2.12 0.49 MRP0004 106.00 107.00 1.196 MAIN Gray 3.66 5.40 0.68 MRP0004 107.00 108.00 1.398 MAIN Gray 2.58 4.07 0.63 MRP0004 108.00 109.00 1.230 FW Gray 0.58 1.53 0.38


Table A_5

Mara Rosa Project



Depth To (m)


(ppm) Te

(ppm) Au:Te Ratio

MRP0005 2.00 3.00 0.890 WST Gray 0.64 1.17 0.55 MRP0005 31.00 32.00 1.110 WST Black 0.57 0.03 19.13 MRP0005 132.17 132.92 0.892 WST Black 1.22 4.32 0.28 MRP0005 136.34 137.06 0.868 HW Gray 1.83 4.67 0.39 MRP0005 137.06 137.80 0.966 HW Gray 1.41 2.92 0.48 MRP0005 137.80 138.45 0.714 HW Gray 0.98 1.84 0.53 MRP0005 166.58 167.49 0.976 HW Gray 0.51 1.31 0.39 MRP0005 167.49 168.34 1.002 HW Gray 0.51 1.41 0.36 MRP0005 183.56 184.31 0.982 MAIN Gray 3.26 3.88 0.84 MRP0005 184.31 185.00 0.796 MAIN Gray 3.03 4.31 0.70 MRP0005 185.00 185.54 0.606 MAIN Gray 0.93 1.90 0.49 MRP0005 185.54 186.36 0.946 MAIN Gray 0.94 1.86 0.50 MRP0005 188.00 188.98 1.088 MAIN Black 0.75 0.89 0.84 MRP0005 188.98 189.73 0.876 MAIN Gray 0.65 1.06 0.62 MRP0005 189.73 190.00 0.328 MAIN Gray 1.16 2.01 0.58 MRP0005 190.00 191.00 1.132 MAIN Gray 1.24 2.05 0.60 MRP0005 191.00 192.00 1.230 FW Gray 0.54 1.21 0.45 MRP0005 192.00 193.00 1.156 FW Gray 0.53 1.22 0.43

Table A_6

Mara Rosa Project



Depth To (m)


(ppm) Te

(ppm) Au:Te Ratio

MRP0006 0.00 0.51 0.648 WST Gray 0.54 0.81 0.66 MRP0006 3.20 4.00 0.642 WST Gray 1.74 2.72 0.64 MRP0006 4.00 5.08 1.212 WST Gray 0.87 2.56 0.34 MRP0006 5.08 5.68 0.308 WST Gray 0.66 2.19 0.30 MRP0006 122.00 123.00 1.050 WST Black 1.31 2.30 0.57 MRP0006 132.63 133.55 1.212 HW Black 0.58 0.62 0.93 MRP0006 133.55 134.50 1.070 HW Gray 0.80 1.99 0.40 MRP0006 134.50 135.35 1.058 HW Gray 1.19 2.20 0.54 MRP0006 135.35 136.00 0.764 HW Gray 1.96 2.20 0.89 MRP0006 136.00 137.00 1.206 HW Gray 0.51 1.03 0.49 MRP0006 137.00 138.00 1.170 HW Gray 1.45 1.98 0.73 MRP0006 138.00 139.00 1.088 HW Gray 0.85 1.44 0.59 MRP0006 139.00 140.00 1.110 HW Gray 0.48 1.10 0.43 MRP0006 140.00 141.00 1.244 HW Gray 2.93 5.27 0.56 MRP0006 141.00 142.00 1.248 HW Gray 0.52 1.86 0.28 MRP0006 145.00 146.00 1.090 HW Gray 0.70 1.95 0.36 MRP0006 150.00 151.00 1.260 MAIN Gray 0.62 2.82 0.22 MRP0006 151.00 152.00 1.204 MAIN Gray 1.18 3.44 0.34 MRP0006 152.00 153.00 1.280 MAIN Gray 1.40 3.43 0.41 MRP0006 153.00 154.00 1.138 MAIN Gray 1.31 3.62 0.36 MRP0006 154.00 155.00 1.186 MAIN Gray 0.00 2.65 0.00 MRP0006 155.00 156.00 1.224 MAIN Gray 0.93 2.56 0.36 MRP0006 156.00 157.00 1.152 MAIN Gray 0.93 2.23 0.42 MRP0006 157.00 158.00 1.276 MAIN Gray 0.96 2.78 0.34 MRP0006 158.00 159.00 1.160 MAIN Gray 0.94 2.33 0.40 MRP0006 159.00 160.00 1.248 MAIN Gray 1.13 2.80 0.40 MRP0006 160.00 161.00 1.106 MAIN Gray 2.69 4.77 0.56 MRP0006 161.00 162.00 1.076 FW Black 0.59 1.99 0.30 MRP0006 207.46 208.00 0.644 WST Black 0.50 0.34 1.47


Table A_7

Mara Rosa Project



Depth To (m)


(ppm) Te

(ppm) Au:Te Ratio

MRP0008 0.00 1.00 1.126 WST Gray 0.74 1.15 0.65 MRP0008 100.21 100.75 0.810 WST Gray 1.73 9.42 0.18 MRP0008 109.00 110.00 1.146 WST Black 0.98 2.57 0.38 MRP0008 110.00 111.00 1.050 WST Gray 0.76 1.35 0.56 MRP0008 133.00 134.00 1.052 HW Black 0.57 1.50 0.38 MRP0008 154.80 155.80 1.088 MAIN Gray 0.96 2.96 0.32 MRP0008 155.80 156.80 1.112 MAIN Gray 0.74 2.80 0.26 MRP0008 156.80 157.80 1.006 MAIN Gray 0.93 3.21 0.29 MRP0008 157.80 159.00 1.438 MAIN Gray 1.10 3.54 0.31 MRP0008 159.00 160.00 1.208 MAIN Gray 0.91 1.92 0.47 MRP0008 160.00 161.00 1.050 MAIN Black 2.35 2.58 0.91

Table A_8

Mara Rosa Project



Depth To (m)


(ppm) Te

(ppm) Au:Te Ratio

MRP0009 72.00 73.00 1.254 WST Gray 1.31 0.22 5.93 MRP0009 111.00 112.00 1.076 HW Gray 0.96 1.14 0.84 MRP0009 115.93 117.08 1.310 HW Gray 2.98 3.78 0.79 MRP0009 117.08 118.00 1.070 HW Gray 0.90 3.37 0.27 MRP0009 123.00 124.00 1.166 HW Gray 0.72 2.19 0.33 MRP0009 124.00 125.00 1.226 HW Gray 0.69 1.32 0.52 MRP0009 129.00 130.00 1.176 MAIN Gray 0.66 1.65 0.40 MRP0009 130.00 131.00 1.320 MAIN Black 0.62 1.31 0.47 MRP0009 131.00 132.00 1.126 MAIN Gray 0.82 2.05 0.40 MRP0009 132.00 133.00 1.148 MAIN Gray 1.55 2.47 0.63 MRP0009 133.00 134.00 1.144 MAIN Gray 2.66 5.62 0.47 MRP0009 134.00 135.00 1.182 MAIN Gray 2.75 4.90 0.56 MRP0009 135.00 136.00 1.070 MAIN Black 2.22 6.03 0.37 MRP0009 136.00 137.00 1.224 MAIN Black 0.76 1.51 0.50 MRP0009 137.00 138.00 1.230 MAIN Black 0.62 1.44 0.43 MRP0009 138.00 139.00 1.216 MAIN Black 0.68 1.17 0.58 MRP0009 139.00 140.00 1.234 MAIN Black 0.56 2.11 0.27 MRP0009 140.00 141.00 1.368 MAIN Gray 0.56 2.21 0.26 MRP0009 141.00 142.00 1.188 MAIN Gray 2.01 3.74 0.54 MRP0009 142.00 143.00 1.238 MAIN Gray 0.55 2.08 0.26 MRP0009 143.00 144.00 1.164 MAIN Gray 0.97 2.57 0.38 MRP0009 144.00 145.00 1.128 MAIN Gray 1.08 2.49 0.43 MRP0009 145.00 146.00 1.200 MAIN Gray 1.37 3.27 0.42 MRP0009 146.00 147.00 1.228 MAIN Black 1.19 3.02 0.39 MRP0009 147.00 147.92 1.080 MAIN Black 2.33 4.08 0.57 MRP0009 147.92 149.00 1.212 MAIN Gray 2.45 4.12 0.59 MRP0009 149.00 150.00 1.252 MAIN Black 1.63 3.59 0.45 MRP0009 152.00 153.00 1.148 MAIN Gray 1.13 2.55 0.44 MRP0009 154.40 155.40 1.326 MAIN Gray 1.38 5.54 0.25 MRP0009 157.00 158.00 1.264 MAIN Black 1.01 2.83 0.36


Table A_9

Mara Rosa Project



Depth To (m)


(ppm) Te

(ppm) Au:Te Ratio

MRP0010 99.92 101.10 1.514 MAIN Black 4.48 5.05 0.89 MRP0010 101.10 102.00 1.085 MAIN Gray 2.48 3.84 0.65 MRP0010 102.00 103.00 1.088 MAIN Black 1.44 2.81 0.51 MRP0010 103.00 104.06 1.290 MAIN Black 1.46 2.24 0.65 MRP0010 104.06 105.00 1.266 MAIN Gray 0.56 1.02 0.55 MRP0010 105.00 106.00 1.232 MAIN Black 1.16 2.21 0.52 MRP0010 106.00 107.00 1.304 MAIN Black 1.47 2.06 0.71 MRP0010 107.00 108.00 1.244 MAIN Gray 2.02 2.94 0.69 MRP0010 108.00 109.00 0.994 MAIN Gray 1.11 2.73 0.41 MRP0010 109.00 109.94 1.100 MAIN Black 1.12 2.75 0.41 MRP0010 109.94 110.55 0.750 MAIN Black 1.51 2.94 0.51 MRP0010 110.55 111.59 1.124 MAIN Black 1.16 2.73 0.43 MRP0010 111.59 112.49 1.014 MAIN Black 0.97 3.23 0.30 MRP0010 112.49 113.48 1.024 MAIN Black 0.53 2.06 0.26 MRP0010 113.48 114.11 0.786 MAIN Black 0.78 2.56 0.30 MRP0010 115.00 115.61 0.788 MAIN Black 0.52 2.06 0.25 MRP0010 115.61 116.55 1.180 MAIN Black 4.97 4.26 1.17 MRP0010 118.00 119.00 1.064 MAIN Black 1.15 3.69 0.31 MRP0010 125.77 126.43 0.808 FW Black 1.08 2.50 0.43 MRP0010 126.43 127.47 1.444 FW Black 0.59 1.35 0.44

Table A_10

Mara Rosa Project



Depth To (m)


(ppm) Te

(ppm) Au:Te Ratio

MRP0011 285.00 287.00 2.442 HW Gray 0.76 1.75 0.43 MRP0011 292.00 293.00 1.094 HW Gray 1.22 15.93 0.08 MRP0011 294.00 295.00 1.150 HW Gray 0.53 1.72 0.31 MRP0011 295.00 296.00 1.030 HW Gray 0.92 2.73 0.34 MRP0011 296.00 297.00 1.152 HW Gray 1.09 2.47 0.44 MRP0011 298.00 299.00 1.272 HW Gray 0.73 2.07 0.35 MRP0011 299.00 300.00 1.160 HW Gray 0.76 2.12 0.36 MRP0011 300.00 301.00 1.172 HW Gray 1.74 3.55 0.49 MRP0011 301.00 302.00 1.174 HW Gray 1.79 4.05 0.44 MRP0011 302.00 303.00 1.182 HW Gray 3.94 4.87 0.81 MRP0011 303.00 304.00 1.236 HW Gray 1.31 2.57 0.51 MRP0011 304.00 305.00 1.096 HW Gray 1.40 3.39 0.41 MRP0011 305.00 306.00 1.220 HW Black 0.87 4.46 0.19 MRP0011 306.00 307.00 1.290 HW Black 1.75 16.92 0.10 MRP0011 307.00 308.00 1.084 HW Black 1.57 15.38 0.10 MRP0011 315.00 316.00 1.192 HW Gray 0.64 4.52 0.14 MRP0011 331.00 332.00 1.084 HW Gray 0.61 1.92 0.32


Table A_11

Mara Rosa Project



Depth To (m)


(ppm) Te

(ppm) Au:Te Ratio

MRP0012 242.00 243.00 1.034 HW Black 0.70 0.95 0.73 MRP0012 245.00 246.00 1.170 HW Black 0.53 0.76 0.70 MRP0012 250.00 251.00 1.160 HW Black 2.31 2.12 1.09 MRP0012 256.00 257.00 1.146 HW Gray 0.61 1.02 0.60 MRP0012 258.00 259.18 1.300 HW Gray 0.79 1.30 0.61 MRP0012 269.00 270.00 1.086 HW Black 0.83 1.22 0.68 MRP0012 291.00 292.25 1.586 HW Black 0.56 0.91 0.62 MRP0012 293.00 294.00 1.238 HW Gray 0.84 2.24 0.38 MRP0012 296.00 297.00 1.164 HW Black 0.53 1.62 0.33 MRP0012 307.00 308.00 1.218 MAIN Black 3.36 4.66 0.72 MRP0012 308.00 309.00 1.126 MAIN Black 0.67 1.83 0.37 MRP0012 309.00 310.00 1.074 MAIN Gray 2.03 2.97 0.68 MRP0012 310.00 310.90 1.096 MAIN Black 0.87 1.70 0.51 MRP0012 312.02 313.00 1.248 MAIN Black 4.50 5.24 0.86 MRP0012 313.00 314.04 1.312 MAIN Black 1.04 1.55 0.67

Table A_12

Mara Rosa Project



Depth To (m)


(ppm) Te

(ppm) Au:Te Ratio

MRP0014 242.00 244.00 2.524 HW Black 0.74 2.02 0.37 MRP0014 252.00 254.00 2.448 HW Black 1.64 2.25 0.73 MRP0014 254.00 256.00 2.536 HW Black 2.84 4.71 0.60 MRP0014 256.00 258.00 2.340 HW Black 0.76 1.71 0.44 MRP0014 258.00 260.00 2.364 HW Black 0.55 1.43 0.38 MRP0014 260.00 262.00 2.275 HW Black 0.51 1.22 0.42 MRP0014 268.00 270.00 2.352 HW Black 0.64 1.29 0.49 MRP0014 285.00 287.00 2.374 HW Black 0.69 2.25 0.30 MRP0014 291.00 293.00 2.414 HW Black 0.54 1.92 0.28 MRP0014 293.00 294.35 1.632 HW Black 0.51 1.63 0.31 MRP0014 294.35 296.35 2.574 HW Black 1.16 1.63 0.71 MRP0014 304.00 306.00 2.438 MAIN Black 0.66 1.68 0.39 MRP0014 306.00 308.00 2.360 MAIN Black 0.83 2.23 0.37 MRP0014 308.00 310.00 2.472 MAIN Black 0.51 1.44 0.35 MRP0014 310.00 312.00 2.410 MAIN Black 1.20 2.55 0.47 MRP0014 312.00 314.00 2.382 MAIN Black 0.92 2.12 0.43 MRP0014 316.00 318.00 2.402 MAIN Gray 1.37 2.67 0.51 MRP0014 330.00 332.00 2.708 FW Gray 0.67 2.64 0.25

Appendix B Comminution Results

Appendix B – Comminution Results Page: 1

BOND ROD MILL CLOSED CIRCUIT GRINDABILITY : 1180 MICROMETERS

SAMPLE IDENTITY MAIN COMPOSITE #1

CLIENT COFFEY MINING PTY LTD

PROJECT No A13025 : AMARILLO GOLD PROJECT

DATE FEBRUARY 2011

WT OF WT OF

PERIOD REVS WT OF WT OF WT WT NET WT NET WT CIRC'TING FRESH U/SIZE

OF 1250 NEW OF OF OF OF LOAD FEED IN FEED

MILL mls FEED O/SIZE U/SIZE U/SIZE U/SIZE ADDED TO TO NEXT

PER REV NEXT CYCLE

(g) (g) (g)* (g)* (g)* (g) (%) CYCLE (g) (g)

1 200 2163.7 2163.7 643.1 1520.6 1255.3 6.276 42 1520.6 186.5

2 143 2163.7 1520.6 940.5 1223.2 1036.7 7.250 77 1223.2 150.0

3 129 2163.7 1223.2 1049.9 1113.8 963.8 7.471 94 1113.8 136.6

4 127 2163.7 1113.8 1081.8 1081.9 945.3 7.444 100 1081.9 132.7

5 128 2163.7 1081.9 1081.8 1081.9 949.2 7.416 100 1081.9 132.7

Note : * = Ex grinding mill

PRODUCT IN THE FEED 12.26 (%)

BULK DENSITY 1.7310 (t/m 3)

IDEAL POTENTIAL PRODUCT 1081.9 (g)

AVERAGE EQUILIBRIUM CIRC LOAD 100 (%)

AVERAGE PRODUCT 7.430 (g/rev)

80 % PASSING FEED SIZE 10459 (µm)

80 % PASSING PRODUCT SIZE 678 (µm)

BOND ROD MILL WORK INDEX ( Kilowatt hours / dry ton ne ) : 13.4


BOND ROD MILL CLOSED CIRCUIT GRINDABILITY : 1180 MICROMETERS

SAMPLE IDENTITY HANGING WALL COMPOSITE #1



DATE FEBRUARY 2011

WT OF WT OF




PER REV NEXT CYCLE

(g) (g) (g)* (g)* (g)* (g) (%) CYCLE (g) (g)

1 200 2173.1 2173.1 657.4 1515.7 1270.5 6.352 43 1515.7 171.1

2 144 2173.1 1515.7 970.3 1202.8 1031.7 7.165 81 1202.8 135.7

3 133 2173.1 1202.8 1036.5 1136.6 1000.9 7.525 91 1136.6 128.3

4 127 2173.1 1136.6 1086.5 1086.6 958.3 7.546 100 1086.6 122.6

5 128 2173.1 1086.6 1086.5 1086.6 964.0 7.531 100 1086.6 122.6









BOND ROD MILL WORK INDEX ( Kilowatt hours / dry ton ne ) : 13.1


BOND BALL MILL CLOSED CIRCUIT GRINDABILITY : 106 MICROMETERS

MAIN COMPOSITE #1



DATE DECEMBER 2010

WT OF WT OF




PER REV NEXT CYCLE

(g) (g) (g)* (g)* (g)* (g) (%) CYCLE (g) (g)

1 150 1285.6 1285.6 952.2 333.4 197.7 1.3178 286 333.4 35.2

2 252 1285.6 333.4 870.4 415.2 380.0 1.5079 210 415.2 43.8

3 215 1285.6 415.2 923.9 361.7 317.9 1.4784 255 361.7 38.2

4 223 1285.6 361.7 918.3 367.3 329.1 1.4758 250 367.3 38.8

5 223 1285.6 367.3 918.3 367.3 328.5 1.4732 250 367.3 38.8









BOND BALL MILL WORK INDEX ( Kilowatt hours / dry to nne ) : 12.9

SAMPLE IDENTITY


BOND BALL MILL CLOSED CIRCUIT GRINDABILITY : 106 MICROMETERS

HANGING WALL COMPOSITE #1



DATE DECEMBER 2010

WT OF WT OF




PER REV NEXT CYCLE

(g) (g) (g)* (g)* (g)* (g) (%) CYCLE (g) (g)

1 200 1288.9 1288.9 880.4 408.5 285.0 1.4249 216 408.5 39.1

2 231 1288.9 408.5 881.0 407.9 368.8 1.5963 216 407.9 39.1

3 206 1288.9 407.9 925.9 363.0 323.9 1.5724 255 363.0 34.8

4 212 1288.9 363.0 920.6 368.3 333.5 1.5732 250 368.3 35.3

5 212 1288.9 368.3 920.6 368.3 333.0 1.5708 250 368.3 35.3









BOND BALL MILL WORK INDEX ( Kilowatt hours / dry to nne ) : 13.0

SAMPLE IDENTITY


SAMPLE IDENTITY MAIN COMPOSITE #1

JOB NUMBER A13025 : AMARILLO GOLD PROJECT


DATE FEBRUARY 2011

Operation Size Weight Weight Weight

(mm) (g) (%) % <

Screening 12.5 505.9 31.7 68.3

10.0 401.0 25.1 43.2

8.00 109.9 6.9 36.3

4.00 102.1 6.4 29.9

2.00 53.1 3.3 26.6

1.00 38.4 2.4 24.2

-1.00 386.7 24.2

Total 1597.1 100.00

PADDLE WEIGHT BEFORE TEST (g) : 88.7236PADDLE WEIGHT AFTER TEST (g) : 88.3826

BOND ABRASION INDEX (Ai) : 0.3410

BOND ABRASION INDEX DETERMINATION

SIZE ANALYSIS : ABRASION INDEX PRODUCT

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.1 1.0 10.0 100.0

% P

AS

SIN

G

SIZE (mm)

BOND ABRASION PRODUCT SIZE ANALYSIS


SAMPLE IDENTITY HANGING WALL COMPOSITE #1

JOB NUMBER A13025 : AMARILLO GOLD PROJECT


DATE FEBRUARY 2011

Operation Size Weight Weight Weight

(mm) (g) (%) % <

Screening 12.5 600.4 37.6 62.4

10.0 383.6 24.0 38.4

8.00 68.6 4.3 34.1

4.00 85.7 5.4 28.7

2.00 42.9 2.7 26.0

1.00 32.9 2.1 24.0

-1.00 382.7 24.0

Total 1596.8 100.00

PADDLE WEIGHT BEFORE TEST (g) : 87.2113PADDLE WEIGHT AFTER TEST (g) : 86.8687

BOND ABRASION INDEX (Ai) : 0.3426

BOND ABRASION INDEX DETERMINATION

SIZE ANALYSIS : ABRASION INDEX PRODUCT

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.1 1.0 10.0 100.0

% P

AS

SIN

G

SIZE (mm)

BOND ABRASION PRODUCT SIZE ANALYSIS

Appendix C Pre-Oxidation & Cyanidation Leach Results

Appendix C – Pre-Oxidation & Cyanidation Leach Results Page: 1

PROJECT A13025 : AMARILLO GOLD PROJECT

CLIENT COFFEY MINING PTY LTDTEST No HS23865

MAIN COMPOSITE #1GRIND P 80 : 45 MICRONS WATER PERTH TAP WATERDATE NOVEMBER 2010

Additions Solution Data Removed In Sample Au Au Au

Time Cumm Leach Extrn. Extrn.

(Hours) Ore Water NaCN Lime Oxygen pH NaCN Au Vol NaCN Au Au Vessel Total Total

(g) (mls) (g) (g) (ppm) (%) (ppm) (ml) (g) (µg) (µg) (µg) (µg) (%)

500.0 750.0 6.1 7.9

0 Start Pre-Ox 0.61 23.5 12.0

2 0.22 26.5 11.8

4 0.18 24.1 11.9

8 0.75 28.7 11.9

12 0.62 24.5 11.9

24 End Pre-Ox 0.00 26.3 12.0

0 Start Cyanidation 750.0 0.38 0.00 21.0 12.0 0.050 0.00 0.00

2 720.0 0.00 0.00 20.0 12.3 0.045 0.64 30 0.014 19 19 461 480 69.91

4 690.0 0.00 0.00 26.9 12.4 0.045 0.71 30 0.014 21 41 490 530 77.25

8 660.0 0.00 0.00 28.9 12.1 0.040 0.82 30 0.012 25 65 541 606 88.30

18 630.0 0.00 0.00 26.3 12.2 0.038 0.87 30 0.011 26 91 548 639 93.11

24 600.0 0.00 0.00 25.4 12.1 0.033 0.88 30 0.010 26 118 528 646 94.03

48 End Cyanidation 570.0 0.00 0.00 21.9 12.1 0.030 0.89 30 0.009 27 144 507 652 94.90

TOTAL 0.38 2.38 180 0.069 144

COMMENTS :

1. NaCN Addition : 0.75 (Kg/t)

Gold 2. NaCN Consumption : 0.27 (Kg/t)

Product Quantity Assay Mass Dist'n 3. Lime Consumption : 4.76 (Kg/t)

(ppm) (µg) (%) 4. Perth tap w ater used : 1.000 (SG)

Solids (g) 500.0 0.07 35 5.10 5. Water Weight To Leach : 750.0 (g)

Solution (mls) 570.0 0.89 507 73.89 6. Grind Size P 80 : 45 (µm)

Solution Samples * 144 21.02 7. Evaporation Losses w ere Made Up For Prior

To Sampling At Each Period.

Total Extraction 94.90 8. 30 mls Solution Samples Were Removed At

Each Sampling Period.

Total 687 100.00 9. Additional assays conducted on 48hr solution for:

Calculated Head 1.37 Ag: 0.28 mg/L Pb: <0.05 mg/L

Assay Head 1.19 / 1.22 Cu: 36.3 mg/L Zn: 0.30 mg/L

Ni: 0.65 mg/L

* : Intermediate solution samples removed during the test.

SAMPLE

24 HR PRE-LEACH OXYGENATION / DIRECT CYANIDATION TI ME LEACH TESTWORK : OXYGEN SPARGE

GOLD EXTRACTION CALCULATIONS

0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

EXT

RA

CT

ION

(%

)

TIME (Hours)

RATE OF GOLD EXTRACTION

Au




HANGING WALL COMPOSITE #1GRIND P 80 : 45 MICRONS WATER PERTH TAP WATERDATE NOVEMBER 2010





500.0 750.0 6.0 8.2

0 Start Pre-Ox 0.60 22.3 12.0

2 0.13 26.5 11.9

4 0.17 25.8 11.9

8 0.27 29.3 11.8

12 0.51 23.4 11.9

24 End Pre-Ox 0.00 27.0 12.0


2 720.0 0.00 0.00 21.9 12.4 0.045 0.67 30 0.014 20 20 482 503 81.05

4 690.0 0.00 0.00 28.3 12.4 0.045 0.72 30 0.014 22 42 497 539 86.85

8 660.0 0.00 0.00 26.6 12.2 0.043 0.76 30 0.013 23 65 502 566 91.31

18 630.0 0.00 0.00 29.4 12.2 0.038 0.77 30 0.011 23 88 485 573 92.37

24 600.0 0.00 0.00 28.7 12.2 0.033 0.78 30 0.010 23 111 468 579 93.39

48 End Cyanidation 570.0 0.00 0.00 24.6 12.0 0.030 0.79 30 0.009 24 135 450 585 94.35

TOTAL 0.38 1.68 180 0.070 135

GOLD EXTRACTION CALCULATIONS COMMENTS :














Ni: 0.50 mg/L


SAMPLE


0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

EXT

RA

CT

ION

(%

)

TIME (Hours)


Au




MAIN COMPOSITE #1GRIND P 80 : 45 MICRONS WATER PERTH TAP WATER

DATE NOVEMBER 2010





500.0 750.0 6.1 8.0

0 Start Pre-Ox 0.61 21.2 12.0

2 0.17 25.1 11.8

4 0.16 26.5 11.9

8 0.11 29.3 11.8

12 0.05 23.0 11.9

24 0.81 27.4 11.4

48 0.00 26.3 12.1

60 0.17 24.8 11.8

72 End Pre-Ox 0.18 29.3 11.6


2 720.0 0.00 0.00 27.4 12.0 0.048 0.66 30 0.014 20 20 475 495 73.20

4 690.0 0.00 0.00 21.3 11.9 0.043 0.75 30 0.013 23 42 518 560 82.79

8 660.0 0.00 0.00 26.8 11.7 0.040 0.82 30 0.012 25 67 541 608 89.93

18 630.0 0.00 0.00 29.3 11.6 0.040 0.85 30 0.012 26 92 536 628 92.86

24 600.0 0.00 0.00 26.4 11.6 0.038 0.86 30 0.011 26 118 516 634 93.79

48 End Cyanidation 570.0 0.00 0.00 28.9 11.6 0.028 0.88 30 0.008 26 145 502 646 95.56

TOTAL 0.38 2.26 180 0.071 145

COMMENTS :














Ni: 0.95 mg/L


SAMPLE



0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

EXT

RA

CT

ION

(%

)

TIME (Hours)


Au




HANGING WALL COMPOSITE #1GRIND P 80 : 45 MICRONS WATER PERTH TAP WATER

DATE NOVEMBER 2010





500.0 750.0 6.0 8.3

0 Start Pre-Ox 0.58 25.3 12.0

2 0.15 28.2 11.9

4 0.16 26.5 11.9

8 0.17 29.3 11.8

12 0.14 26.4 11.9

24 0.28 28.7 11.5

48 0.00 27.3 12.0

60 0.00 26.9 12.0

72 End Pre-Ox 0.10 21.4 11.7


2 720.0 0.00 0.00 26.3 12.0 0.048 0.68 30 0.014 20 20 490 510 79.25

4 690.0 0.00 0.00 23.8 11.9 0.045 0.75 30 0.014 23 43 518 560 87.09

8 660.0 0.00 0.00 28.4 11.7 0.043 0.79 30 0.013 24 67 521 588 91.38

18 630.0 0.00 0.00 25.0 11.7 0.040 0.81 30 0.012 24 91 510 601 93.43

24 600.0 0.00 0.00 29.7 11.7 0.038 0.82 30 0.011 25 116 492 608 94.41

48 End Cyanidation 570.0 0.00 0.00 27.7 11.6 0.030 0.83 30 0.009 25 140 473 614 95.34

TOTAL 0.38 1.58 180 0.073 140

GOLD EXTRACTION CALCULATIONS COMMENTS :














Ni: 0.25 mg/L


SAMPLE


0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

EXT

RA

CT

ION

(%

)

TIME (Hours)


Au









500.0 750.0 6.1 8.1


2 720.0 0.00 0.00 25.7 10.1 0.048 0.47 30 0.014 14 14 338 353 50.63

4 690.0 0.00 0.00 29.8 10.1 0.045 0.54 30 0.014 16 30 369 399 57.35

8 660.0 0.00 0.00 26.5 10.1 0.043 0.62 30 0.013 18 49 406 455 65.28

18 630.0 0.00 0.00 24.1 10.1 0.043 0.77 30 0.013 23 72 485 557 79.97

24 600.0 0.00 0.00 21.1 10.0 0.040 0.79 30 0.012 24 95 471 566 81.33

48 End Cyanidation 570.0 0.00 0.00 26.9 10.0 0.038 0.86 30 0.011 26 121 490 611 87.79

TOTAL 0.38 0.62 180 0.077 121

COMMENTS :














Ni: 0.85 mg/L


SAMPLE

DIRECT CYANIDATION TIME LEACH TESTWORK : OXYGEN SPARGE


0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

EXT

RA

CT

ION

(%

)

TIME (Hours)


Au









500.0 750.0 6.4 8.3


2 720.0 0.00 0.00 26.9 10.1 0.045 0.40 30 0.014 12 12 288 300 37.72

4 690.0 0.00 0.00 28.7 10.1 0.043 0.46 30 0.013 14 26 317 343 43.15

8 660.0 0.00 0.00 23.2 10.2 0.043 0.58 30 0.013 17 43 383 426 53.56

18 630.0 0.00 0.00 21.4 10.1 0.038 0.70 30 0.011 21 64 441 505 63.52

24 600.0 0.00 0.00 25.6 10.1 0.035 0.74 30 0.011 22 86 444 530 66.68

48 End Cyanidation 570.0 0.00 0.00 29.8 10.0 0.035 0.89 30 0.011 27 113 507 620 78.00

TOTAL 0.38 0.21 180 0.072 113

COMMENTS :














Ni: 1.05 mg/L


SAMPLE

DIRECT CYANIDATION TIME LEACH TESTWORK : OXYGEN SPARGE


0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

EXT

RA

CT

ION

(%

)

TIME (Hours)


Au









500.0 750.0 6.2 8.1

0 Start Pre-Ox 0.96 22.5 12.0

2 0.00 26.9 11.9

4 0.00 28.7 11.9

6 End Pre-Ox 0.00 21.4 11.7


2 720.0 0.00 0.00 29.5 11.9 0.048 0.62 30 0.014 18 18 443 461 64.36

4 690.0 0.00 0.00 28.1 11.9 0.045 0.76 30 0.014 23 41 521 562 78.43

8 660.0 0.00 0.00 24.3 11.9 0.040 0.82 30 0.012 25 66 541 607 84.69

18 630.0 0.00 0.00 26.3 11.8 0.043 0.87 30 0.013 26 92 545 637 88.83

24 600.0 0.00 0.00 22.5 11.8 0.038 0.90 30 0.011 27 119 540 659 91.91

48 End Cyanidation 570.0 0.00 0.00 29.5 11.7 0.028 0.93 30 0.008 28 147 530 677 94.42

TOTAL 0.38 0.96 180 0.073 147

COMMENTS :














Ni: 0.65 mg/L


SAMPLE

6 HR PRE-LEACH OXYGENATION / DIRECT CYANIDATION TIM E LEACH TESTWORK : OXYGEN SPARGE


0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

EXT

RA

CT

ION

(%

)

TIME (Hours)


Au









500.0 750.0 8.0 8.2

0 Start Pre-Ox 0.80 21.4 12.0

2 0.00 26.9 12.0

4 0.00 28.7 11.9

6 End Pre-Ox 0.00 26.4 11.9


2 720.0 0.00 0.00 29.9 11.9 0.043 0.61 30 0.013 18 18 439 458 61.24

4 690.0 0.00 0.00 24.3 11.9 0.040 0.78 30 0.012 23 42 535 576 77.14

8 660.0 0.00 0.00 21.5 11.9 0.038 0.85 30 0.011 26 67 561 628 84.07

18 630.0 0.00 0.00 26.5 11.9 0.035 0.94 30 0.011 28 95 592 687 92.02

24 600.0 0.00 0.00 29.8 11.9 0.033 0.96 30 0.010 29 124 576 700 93.71

48 End Cyanidation 570.0 0.00 0.00 24.3 11.9 0.030 0.98 30 0.009 29 153 559 712 95.31

TOTAL 0.38 0.80 180 0.066 153

COMMENTS :














Ni: 0.55 mg/L


SAMPLE

6 HR PRE-LEACH OXYGENATION / DIRECT CYANIDATION TIM E LEACH TESTWORK : OXYGEN SPARGE


0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

EXT

RA

CT

ION

(%

)

TIME (Hours)


Au









500.0 750.0 6.0 8.0

0 Start Pre-Ox 1.07 21.6 12.0

2 0.00 26.6 12.1

4 0.00 29.8 12.1

8 0.00 21.4 12.0

12 End Pre-Ox 0.00 20.3 12.0


2 720.0 0.00 0.00 22.7 12.0 0.048 0.67 30 0.014 20 20 482 503 70.04

4 690.0 0.00 0.00 26.3 12.0 0.045 0.79 30 0.014 24 44 545 589 82.09

8 660.0 0.00 0.00 26.8 12.0 0.043 0.82 30 0.013 25 68 541 610 84.97

18 630.0 0.00 0.00 24.0 12.0 0.040 0.89 30 0.012 27 95 561 656 91.41

24 600.0 0.00 0.00 23.7 12.0 0.038 0.91 30 0.011 27 122 546 668 93.17

48 End Cyanidation 570.0 0.00 0.00 26.9 12.0 0.030 0.93 30 0.009 28 150 527 677 94.42

TOTAL 0.38 1.07 180 0.073 150

COMMENTS :














Ni: 0.75 mg/L


SAMPLE



0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

EXT

RA

CT

ION

(%

)

TIME (Hours)


Au









500.0 750.0 8.2 8.0

0 Start Pre-Ox 0.89 22.4 12.0

2 0.00 29.6 12.0

4 0.00 25.0 12.0

8 0.00 26.9 12.0

12 End Pre-Ox 0.00 21.4 12.0


2 720.0 0.00 0.00 22.2 12.0 0.048 0.64 30 0.014 19 19 461 480 67.63

4 690.0 0.00 0.00 26.6 12.0 0.045 0.79 30 0.014 24 43 545 588 82.85

8 660.0 0.00 0.00 29.3 12.0 0.040 0.87 30 0.012 26 69 574 643 90.63

18 630.0 0.00 0.00 24.8 12.0 0.038 0.89 30 0.011 27 96 561 656 92.49

24 600.0 0.00 0.00 26.3 12.0 0.035 0.90 30 0.011 27 123 540 663 93.38

48 End Cyanidation 570.0 0.00 0.00 21.4 12.0 0.035 0.92 30 0.011 28 150 524 675 95.07

TOTAL 0.38 0.89 180 0.072 150

COMMENTS :














Ni: 0.65 mg/L


SAMPLE



0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

EXT

RA

CT

ION

(%

)

TIME (Hours)


Au









500.0 750.0 6.4 8.2

0 Start Pre-Ox 0.88 20.4 11.0

2 0.00 29.3 11.2

4 0.00 26.5 11.1

8 0.00 21.4 11.1

12 0.00 29.8 11.1

24 End Pre-Ox 0.00 26.3 10.9


2 720.0 0.00 0.00 25.7 10.9 0.043 0.55 30 0.013 16 16 392 409 59.55

4 690.0 0.00 0.00 28.9 10.9 0.038 0.60 30 0.011 18 34 414 448 65.32

8 660.0 0.00 0.00 26.2 10.9 0.038 0.68 30 0.011 20 55 449 504 73.36

18 630.0 0.00 0.00 24.7 10.9 0.035 0.76 30 0.011 23 78 479 556 81.05

24 600.0 0.00 0.00 26.7 10.7 0.035 0.80 30 0.011 24 101 477 578 84.27

48 End Cyanidation 570.0 0.00 0.00 29.3 10.7 0.028 0.85 30 0.008 26 127 485 611 89.07

TOTAL 0.38 0.88 180 0.065 127

COMMENTS :














Ni: 0.35 mg/L


SAMPLE



0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

EXT

RA

CT

ION

(%

)

TIME (Hours)


Au









500.0 750.0 8.6 8.2

0 Start Pre-Ox 0.54 23.4 11.0

2 0.00 29.6 11.0

4 0.00 25.1 11.0

8 0.00 20.4 11.0

12 0.00 27.8 10.9

24 End Pre-Ox 0.00 29.3 10.9


2 720.0 0.00 0.00 22.2 10.9 0.038 0.48 30 0.011 14 14 346 360 48.77

4 690.0 0.00 0.00 25.8 10.9 0.038 0.55 30 0.011 17 31 380 410 55.59

8 660.0 0.00 0.00 26.3 10.9 0.038 0.64 30 0.011 19 50 422 473 64.01

18 630.0 0.00 0.00 24.5 10.9 0.035 0.70 30 0.011 21 71 441 512 69.37

24 600.0 0.00 0.00 22.0 10.9 0.035 0.77 30 0.011 23 94 462 556 75.35

48 End Cyanidation 570.0 0.00 0.00 29.3 10.7 0.028 0.84 30 0.008 25 119 479 598 81.03

TOTAL 0.38 0.54 180 0.064 119

COMMENTS :














Ni: 0.35 mg/L


SAMPLE



0

10

20

30

40

50

60

70

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90

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

EXT

RA

CT

ION

(%

)

TIME (Hours)


Au









500.0 750.0 6.4 8.0

0 Start Pre-Ox 0.70 23.5 12.0

2 0.00 26.4 11.8

4 0.00 27.8 11.8

8 0.00 29.3 11.5

12 0.00 21.4 11.5

24 End Pre-Ox 0.00 26.9 11.5


2 720.0 0.00 0.00 23.4 11.6 0.048 0.59 30 0.014 18 18 421 439 63.16

4 690.0 0.00 0.00 27.1 11.6 0.048 0.64 30 0.014 19 37 442 478 68.86

8 660.0 0.00 0.00 25.6 11.6 0.045 0.74 30 0.014 22 59 485 544 78.29

18 630.0 0.00 0.00 29.8 11.5 0.040 0.81 30 0.012 24 83 507 590 84.94

24 600.0 0.00 0.00 27.3 11.5 0.040 0.83 30 0.012 25 108 495 603 86.76

48 End Cyanidation 570.0 0.00 0.00 23.6 11.5 0.035 0.85 30 0.011 25 133 482 615 88.48

TOTAL 0.38 0.70 180 0.077 133

COMMENTS :














Ni: 0.20 mg/L


SAMPLE



0

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20

30

40

50

60

70

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90

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

EXT

RA

CT

ION

(%

)

TIME (Hours)


Au









500.0 750.0 6.2 8.4

0 Start Pre-Ox 0.75 22.4 12.0

2 0.00 28.9 11.8

4 0.00 28.1 11.8

8 0.00 21.4 11.7

12 0.00 20.3 11.7

24 End Pre-Ox 0.00 23.6 11.6


2 720.0 0.00 0.00 29.8 11.7 0.048 0.54 30 0.014 16 16 385 401 57.14

4 690.0 0.00 0.00 24.2 11.7 0.045 0.63 30 0.014 19 35 431 466 66.37

8 660.0 0.00 0.00 26.5 11.7 0.043 0.73 30 0.013 22 57 482 539 76.68

18 630.0 0.00 0.00 23.5 11.6 0.040 0.83 30 0.012 25 81 520 601 85.61

24 600.0 0.00 0.00 29.2 11.6 0.040 0.86 30 0.012 26 107 516 623 88.75

48 End Cyanidation 570.0 0.00 0.00 25.6 11.6 0.038 0.88 30 0.011 26 134 499 632 90.03

TOTAL 0.38 0.75 180 0.076 134

COMMENTS :














Ni: 0.25 mg/L


SAMPLE



0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

EXT

RA

CT

ION

(%

)

TIME (Hours)


Au









500.0 750.0 6.4 8.0

0 Start Pre-Ox 0.79 23.5 12.0

2 0.00 26.9 11.8

4 0.00 28.4 11.8

8 0.00 21.1 11.8

12 0.00 26.5 11.7

24 End Pre-Ox 0.00 26.9 11.5


2 720.0 0.00 0.00 24.5 11.5 0.048 0.59 30 0.014 18 18 425 443 62.78

4 690.0 0.00 0.00 23.6 11.5 0.045 0.65 30 0.014 20 37 449 486 68.91

8 660.0 0.00 0.00 29.2 11.5 0.043 0.75 30 0.013 23 60 495 555 78.70

18 630.0 0.00 0.00 25.5 11.4 0.040 0.82 30 0.012 25 84 517 601 85.26

24 600.0 0.00 0.00 25.9 11.3 0.038 0.85 30 0.011 26 110 510 620 87.94

48 End Cyanidation 570.0 0.00 0.00 22.0 11.3 0.035 0.88 30 0.011 26 136 499 635 90.07

TOTAL 0.38 0.79 180 0.075 136

COMMENTS :














Ni: 0.35 mg/L


SAMPLE



0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

EXT

RA

CT

ION

(%

)

TIME (Hours)


Au









500.0 750.0 6.6 8.1

0 Start Pre-Ox 0.82 23.6 12.0

2 0.00 25.4 11.9

4 0.00 28.9 11.9

8 0.00 26.3 11.8

12 0.00 21.4 11.8

24 End Pre-Ox 0.00 27.3 11.7


2 720.0 0.00 0.00 22.5 11.7 0.048 0.64 30 0.014 19 19 461 480 61.31

4 690.0 0.00 0.00 26.9 11.7 0.048 0.74 30 0.014 22 41 511 552 70.51

8 660.0 0.00 0.00 24.5 11.7 0.045 0.80 30 0.014 24 65 528 593 75.80

18 630.0 0.00 0.00 28.9 11.6 0.040 0.91 30 0.012 27 93 573 666 85.07

24 600.0 0.00 0.00 26.3 11.5 0.040 0.94 30 0.012 28 121 564 685 87.48

48 End Cyanidation 570.0 0.00 0.00 21.2 11.5 0.035 1.02 30 0.011 31 152 581 733 93.61

TOTAL 0.38 0.82 180 0.077 152

COMMENTS :














Ni: 0.40 mg/L


SAMPLE



0

10

20

30

40

50

60

70

80

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100

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(%

)

TIME (Hours)


Au




FOOTWALL COMPOSITEGRIND P 80 : 45 MICRONS WATER PERTH TAP WATERDATE FEBRUARY 2011





500.0 750.0 6.2 7.9

0 Start Pre-Ox 0.88 22.6 12.0

2 0.05 27.6 11.9

4 0.00 29.5 12.0

8 0.00 21.3 12.0

12 End Pre-Ox 0.00 27.3 11.9


2 720.0 0.00 0.00 28.3 11.8 0.040 0.32 30 0.012 10 10 230 240 63.31

4 690.0 0.00 0.00 27.9 11.8 0.040 0.37 30 0.012 11 21 255 276 72.80

8 660.0 0.00 0.00 25.0 11.8 0.038 0.40 30 0.011 12 33 264 297 78.26

18 630.0 0.00 0.00 23.5 11.8 0.033 0.43 30 0.010 13 46 271 317 83.49

24 End Cyanidation 600.0 0.00 0.00 27.1 11.8 0.028 0.45 30 0.008 14 59 270 329 86.81

TOTAL 0.38 0.93 150 0.054 59

COMMENTS :














Ni: 0.35 mg/L


SAMPLE



0

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Au

Appendix D FS Metallurgical Testwork Program


Appendix D – Metallurgical Testwork Program Page: 1

1 METALLURGICAL TESTWORK PROGRAM

1.1 Introduction

The focus of the metallurgical testwork to date was to evaluate a number of processing options. A number of basic flowsheet scenarios were tested and the results analysed to determine the likely processing route. The results from this work were used to identify the base case for feasibility study (FS) metallurgical testwork program.

The testwork program outlined below aims to confirm and optimise the flowsheet selected from previous investigations. The program also includes the various ancillary tests such as thickening and viscosity work to finalise the design criteria and aid in equipment selection and sizing.

At feasibility study level the metallurgical testwork program should be completed such that virtually no assumptions are required. The program is typically performed on a number of composite samples that are representative of the major mineralogical domains or if possible the likely mill feed if a preliminary mine plan is available.

Variability testing must also be included.

1.2 Background

The testwork completed to date on the Mara Rosa deposit identified a viable process route and simple confirmation of this testwork with the additional detail as described above should be adequate.

However, there are two aspects of the Mara Rosa deposit that are less ideal as compared to other deposits and thereby warrant further investigation from an alternative standpoint. These are the relatively fine grind size and the requirement for additional tankage for the pre-oxidation of the tellurides.

It is therefore proposed that a number of additional tests take place with the view of understanding and optimising these requirements.

The finer grind that is required is almost entirely due to the need to produce a large surface area of gold tellurides so that they can readily oxidise at an elevated pH. That is to say, that it is possible that the non-telluride gold may not require such a fine grind. One of the mistakes that is often made and was done so in the earlier Mara Rosa testwork is to assume that when a flotation concentrate is recovered, that the flotation tail does not contain recoverable gold.

It is possible that such a flotation tail may contain readily recoverable cyanidable gold, which only requires grinding to a P80 of 75µm or 106µm for example. Provided that the sulphide and telluride component of the gold can be recovered in a flotation concentrate, then it can be finely ground to 45µm separately whilst the remaining material is cyanided at a coarser grind. The ability for this theory to work is currently unknown and untested and is therefore recommended at this stage, as it would represent a potential improvement in both a capital and operating cost perspective.



In addition to this, the nature and contribution of the gold tellurides that exist in the Mara Rosa deposit are still not fully understood. A method for dealing with them is, but conventional methodologies do not isolate the contribution of sulphides versus tellurides, which could provide an improved understanding of the extraction process and hence the capital and operating cost structure.

Testwork using the Albion process, which has been previously discussed in potential testwork options, has the ability to isolate the contributions of sulphides and tellurides to a large extent. In addition to this, a large amount of knowledge of the deportment and nature of the gold can be formulated with some of these tests.

Hence, the testwork programme requirements that are discussed in the following sections comprise of two types of testwork; that which is required for the study to progress to a FS level based on the existing flowsheet and typical corporate, financial and technical requirements and that which is aimed at further understanding the complexities of the Mara Rosa deposit so that alternative options can be assessed that may provide significant improvements in the project economics.

1.3 Study Deliverables

The outcomes that should be derived from a feasibility level metallurgical and process engineering study include:

Design criteria

Mass Balance

Equipment lists

Process description

General arrangements and outline drawings

Capital and operating cost estimates

Project schedule

Specifications

1.4 Sample Selection

At a feasibility level, PQ or HQ diamond drill core would normally be the preferred sample type, as a minimum drill core diameter is required for certain tests such as the physical characterisation. NQ drill core may be combined with PQ core for the testwork programme.

For the completion of the feasibility testwork programme, ideally, approximately 100kg of material would need to be available for each composite sample and approximately 50kg for each variability sample depending on the amount of flotation tests that might be performed.

Depending on the selected flowsheet, a bulk sample from the deposit may be utilised for comprehensive flotation testwork.



The composite samples for Mara Rosa will likely come from the existing samples which are held in reserve at Ammtec in Perth. Ideally the composite samples should be as close to possible as that used in the PFS testwork.

The variability samples may need to be sourced from the subsequent geotechnical drilling that has taken place, or is to take place at the Mara Rosa deposit. A review of plan or cross-section data for these holes will be required to select approximately 6 – 8 samples for variability work.

1.5 Metallurgical Testwork

The following outlines the tests to be performed on the composite and variability samples and estimate of the required sample size and weight.

Necessary with current flowsheet:

Physical characterisation including: (~10kg)

UCS - Unconfined Compressive Strength (5 or 10 repeats)

BWi – Bond Ball Mill Work Index

RWi – Bond Rod Mill Work Index

Ai – Abrasion Index

Note: UCS testing requires a sample of 50mmØ and 125mm length. Ideally, ten repeats are completed; however, five can be sufficient. The products of some of these tests can be used for other tests.

Cyanidation testwork to optimise pre-oxidation and reagent addition for both composite samples and variability samples (after optimisation of composites)

Settling/thickening testwork (~10kg)

Viscosity testwork (~2kg)

Geochemical testwork (~2kg)

AMD waste

AMD tails

Engineering testwork (~300kg from bulk sample containing all three domains)

Conveyor surcharge angle

Angle of repose

Bin drawdown angle

Dust extinction moisture



Additional testwork for alternatives and optimisation on bulk composite from all three domains:

Grind establishment at 105µm, 106µm, 75µm, 53µm, 45µm (<1kg)

Flotation sighter tests at 105µm / 106µm / 75µm (~30kg each size)

Float concentrate:

Assay Au, Te

Regrind to 75µm, 53µm, 45µm

Cyanidation leach on 3 sizes with pre-oxidation

Cyanidation leach on 3 sizes without pre-oxidation

Float tail

Assay Au, Te

Cyanidation leach without pre-oxidation

ALBION testwork on composite sample where solution samples are removed at different stages to identify, cyanide soluble gold prior to sulphide oxidation, after sulphide oxidation, after telluride oxidation.

An outline of the above testwork program including estimated sample type and number requirements is given in Figure 1.5_1.



Figure 1.5_1 Metallurgical Program Schedule

Mara Rosa Metallurgical Testwork Report · Principal Consultant - Metallurgy . Coffey Mining Pty Ltd DOCUMENT INFORMATION Mara Rosa Pre-Feasibility Study – MINEWPER00525AC (10410)

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