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Certificate of Analysis, ROCKLABS Reference Material Si54, 19 April, 2010. Page 1 of 6.

Certificate of Analysis

Reference Material Si54

Recommended Gold Concentration: 1.780 µg/g

95% Confidence Interval: +/- 0.011 µg/g

The above values apply only to product in jars or sachets which have an identification number

within the following range: 207 954 – 209 655.

Prepared and Certified By: Malcolm Smith BSc, FNZIC

Malcolm Smith Reference Materials Ltd

40 Oakford Park Crescent, Greenhithe

North Shore City 0632

NEW ZEALAND

Email: [email protected]

Telephone: +64 9 444 3534

Date of Certification: 19 April 2010

Certificate Status: Original

Available Packaging: This reference material has been packed in wide-

mouthed jars that contain 2.5 kg of product. The

contents of some jars may be subsequently

repacked into sealed polyethylene sachets.

Origin of Reference Material: Feldspar minerals, basalt and iron pyrites with

minor quantities of finely divided gold-

containing minerals that have been screened to

ensure there is no gold nugget effect.

Supplier of Reference Material: ROCKLABS Ltd

P O Box 18 142

Auckland 1743

NEW ZEALAND


Website: www.rocklabs.com

Telephone: +64 9 634 7696


Description: The reference material is a light grey powder that has been

well mixed and a homogeneity test carried out after the entire

batch was packaged into wide-mouthed jars. There is no soil

component. The product contains crystalline quartz and

therefore dust from it should not be inhaled.

The approximate chemical composition is:

(Uncertified Values)

%

SiO2 54.34

Al2O3 15.89

Na2O 3.72

K2O 5.73

CaO 3.91

MgO 3.27

TiO2 0.98

MnO 0.07

P2O5 0.28

Fe2O3 5.06

Fe 2.6

S 2.8

Intended Use: This reference material is designed to be included with every

batch of samples analysed and the results plotted for quality

monitoring and assessment purposes.

Stability: The container (jar or sachet) and its contents should not be

heated to temperatures higher than 50 °C. Iron pyrites are

likely to oxidize in the air but tests have shown that the

increase in weight of an exposed reference material of similar

matrix, in the Auckland climate, is less than 0.1% per year.

Method of Preparation: Pulverized feldspar minerals, basalt rock and barren iron

pyrites were blended with finely pulverized and screened,

gold-containing minerals. Once the powders were uniformly

mixed the composite was placed into 1702 wide-mouthed

jars, each bearing a unique number. 48 jars were randomly

selected from the packaging run and material from these jars

was used for both homogeneity and consensus testing.

Homogeneity Assessment:

An independent laboratory carried out gold analysis by fire assay of 30 g portions,

using an AAS finish. Steps were taken to minimize laboratory method variation in

order to better detect any variation in the candidate reference material.


Homogeneity Assessment continued:

The contents of six randomly selected jars were compacted by vibration (to simulate

the effect of freighting) and five samples removed successively from top to bottom

from each jar. In addition, five samples were removed from the last jar in the series.

A sample was also removed from the top of each of the 48 jars randomly selected

from the 1702 jars in the batch. The results of analysis of the 83 samples (randomly

ordered and then consecutively numbered before being sent to the laboratory)

produced a relative standard deviation of 1.7 %.

Analytical Methodology:

Once homogeneity had been established, two sub-samples were submitted to a

number of well-recognized laboratories in order to assign a gold value by consensus

testing. The sub-samples were drawn from the 48 randomly selected jars and each

laboratory received samples from two different jars. Indicative concentration ranges

were given. All laboratories used fire assay for the gold analysis, with most using an

instrument finish and some a gravimetric finish.

Calculation of Certified Value:

Results for gold were returned from 43 laboratories. Statistical analysis to identify

outliers was carried out using the principles detailed in sections 7.3.2 – 7.3.4, ISO

5725-2: 1994. Assessment of each laboratory’s performance was carried out on the

basis of z-scores, partly based on the concept described in ISO/IEC Guide 43-1.

Details of the criteria used in these examinations are available on request. As a result

of these statistical analyses, five sets of results were excluded for the purpose of

assigning a gold concentration value to this reference material. A recommended

value was thus calculated from the average of the remaining n = 38 sets of replicate

results. The 95 % confidence interval was estimated using the formula:-

X ± ts/√n

(where X is the estimated average, s is the estimated standard deviation of the

laboratory averages, and t is the 0.025 tail-value from Student’s t-distribution with n-

1 degrees of freedom). The recommended value is provided at the beginning of the

certificate in µg/g (ppm) units. A summary of the results used to calculate the

recommended value is listed on page 4 and the names of the laboratories that

submitted results are listed on page 5. The results are listed in increasing order of the

individual laboratory averages.

Statistical analysis of the consensus test results has been carried out by independent

statistician, Tim Ball.


Summary of Results Used to Calculate Gold Value (Listed in increasing order of individual laboratory averages)

Gold (ppm)

Sample 1 Sample 2 Average

1.71 1.72 1.715

1.73 1.70 1.715

1.748 1.709 1.728

1.770 1.719 1.745

1.77 1.725 1.748

1.760 1.737 1.749

1.730 1.770 1.750

1.75 1.75 1.750

1.76 1.74 1.750

1.75 1.77 1.760

1.77 1.75 1.760

1.743 1.779 1.761

1.744 1.778 1.761

1.763 1.760 1.762

1.78 1.75 1.765

1.795 1.755 1.775

1.77 1.78 1.775

1.79 1.760 1.775

1.80 1.76 1.780

1.770 1.790 1.780

1.780 1.785 1.783

1.775 1.795 1.785

1.80 1.77 1.785

1.80 1.79 1.795

1.80 1.79 1.795

1.792 1.807 1.800

1.80 1.80 1.800

1.81 1.79 1.800

1.78 1.82 1.800

1.82 1.785 1.803

1.790 1.815 1.803

1.795 1.830 1.813

1.83 1.81 1.820

1.82 1.82 1.820

1.795 1.855 1.825

1.83 1.82 1.825

1.830 1.835 1.833

1.86 1.88 1.870

Average of 38 sets = 1.780 ppm

Standard deviation of 38 sets = 0.034 ppm

Relative standard deviation = 1.9 %

95% Confidence interval for average = 0.011 ppm

Note: this standard deviation should not be used as

a basis to set control limits when plotting results

from an individual laboratory.


Participating Laboratories

Australia ALS Mineral, Kalgoorlie

ALS Mineral, Orange

ALS Mineral, Perth

ALS Mineral, Townsville

Amdel Ltd, Adelaide

Amdel Ltd, Kalgoorlie

Genalysis Laboratory Services, Perth

Independent Assay Laboratories, Perth

SGS Minerals Services, Perth

Standard and Reference Laboratories, Perth

Ultra Trace Pty Ltd, Perth

Burkina Faso ALS Mineral, Burkina Faso

Canada Acme Analytical Laboratories Ltd, Vancouver

ALS Mineral, Val d’Or

ALS Mineral, Vancouver

Assayers Canada, Vancouver

International Plasma Labs Ltd, Richmond

Loring Laboratories Ltd, Calgary

SGS Mineral Services, Lakefield

Techni-Lab S.G.B. Abitibi Inc, Quebec

TSL Laboratories Inc, Saskatoon

Chile Acme Analytical Laboratories Ltd, Santiago

ALS Mineral, La Serena

Kyrgyzstan Stewart Assay and Environmental Laboratories LLC, Kara-Balta

Malaysia Performance Laboratories, Raub

Mali ALS Mineral, Bamako

New Zealand Amdel Ltd, Reefton

SGS Minerals Services, Waihi

Peru ALS Mineral, Lima

Inspectorate Services Peru S.A.C., Callao

Minera Yanacocha SRL – Newmont, Lima

South Africa AB Analytical Laboratory Services, Boksburg

ALS Mineral, Johannesburg

Anglo Research, Johannesburg

Goldfields West Wits Analytical Laboratory

Performance Laboratories, Allanridge

Performance Laboratories, Randfontein

SGS South Africa (Pty) Ltd, Johannesburg

UK Inspectorate International Ltd, Essex

USA ALS Mineral, Reno

Barrick Goldstrike – Met Services

Newmont Mining Corporation, Carlin Laboratory

Newmont Mining Corporation, Lone Tree Laboratory


Instructions and Recommendations for Use:

Weigh out quantity usually used for analysis and analyze for total gold by normal

procedure. Homogeneity testing has shown that consistent results are obtainable for gold

when 30g portions are taken for analysis.

We quote a 95% confidence interval for our estimate of the declared value. This

confidence interval reflects our uncertainty in estimating the true value for the gold

content of the reference material. The interval is chosen such that, if the same procedure as

used here to estimate the declared value were used again and again, then 95% of the trials

would give intervals that contained the true value. It is a reflection of how precise the trial

has been in estimating the declared value. It does not reflect the variability any particular

laboratory will experience in its own repetitive testing.

Some users in the past have misinterpreted this confidence interval as a guide as to how

different an individual test result should be from the declared value. Some mistakenly use

this interval, or the standard deviation from the consensus test, to set limits for control

charts on their own routine test results using the reference material. Such use inevitably

leads to many apparent out-of-control points, leading to doubts about the laboratory’s

testing, or of the reference material itself.

A much better way of determining the laboratory performance when analysing the

reference material is to accumulate a history of the test results obtained, and plot them on a

control chart. The appropriate centre line and control limits for this chart should be based

on the average level and variability exhibited in the laboratory’s own data. This chart will

provide a clear picture of the long-term stability or otherwise of the laboratory testing

process, providing good clues as to the causes of any problems. To help our customers do

this more simply for themselves, we can provide a free Excel template that will produce

sensible graphs, with intelligently chosen limits, from the customer’s own data.

Legal Notice:

This certificate and the reference material described in it have been prepared with due care

and attention. However ROCKLABS Ltd, Malcolm Smith Reference Materials Ltd and

Tim Ball Ltd accept no liability for any decisions or actions taken following the use of the

reference material.

References:

For further information on the preparation and validation of this reference material please

contact Malcolm Smith.

Certifying Officer Independent Statistician

M G Smith BSc, FNZIC Tim Ball BSc (Hons)

Certificate of Analysis, ROCKLABS Reference Material SI15, 26 September 2003. Page 1 of 1.


Reference Material SI15

Recommended Values and 95% Confidence Intervals Gold Concentration: 1.805 (+/- 0.028) µg/g Silver concentration: 19.68 (+/- 0.46) µg/g

The above values apply only to product in jars or sachets which have an identification number within the following range: The number range is not published on the website

Prepared and Certified By: Malcolm Smith BSc, FNZIC Malcolm Smith Reference Materials Ltd 2 Morriggia Place Auckland 10 NEW ZEALAND Telephone: +64 9 444 3534 Telefax: +64 9 444 7739 Email: [email protected]

Date of Certification: 26 September 2003


Available Packaging: This reference material has been packed in wide-mouthed jars that contain 2.5kg of product. The contents of some jars may be subsequently repacked into sealed polyethylene sachets.

Origin of Reference Material: Feldspars and iron pyrites with minor quantities of finely divided gold and silver-containing minerals that have been screened to ensure there is no gold nugget effect.

Supplier of Reference Material: ROCKLABS Ltd P O Box 18 142 Auckland NEW ZEALAND Email: [email protected] Telephone: +64 9 634 7696


Description: The component minerals have been well mixed and a homogeneity test carried out after the entire batch was packaged into wide-mouthed jars to ascertain that the gold is evenly distributed throughout the reference material. There is no soil component. The product contains crystalline quartz and therefore dust from it should not be inhaled.


(Uncertified Values) % SiO2 64.33

Al2O3 17.83

Na2O 10.15

K2O 0.25

CaO 0.48

MgO 0.09

TiO2 0.06

MnO 0.01

P2O5 0.14

Fe 3.2

S 2.9

Intended Use: This reference material is designed to be included with every batch of samples analysed and the results plotted for quality monitoring purposes.

Stability: The container (jar or sachet) and its contents should not be heated to temperatures higher than 50 °C. Iron pyrites are likely to oxidize in the air but preliminary tests have shown that the increase in weight of an exposed reference material of similar matrix, in the Auckland climate, is less than 0.1% per year.

Instructions for Use: Weigh out quantity usually used for analysis and analyze by normal procedure. Homogeneity testing has shown that consistent results are obtainable for gold when 30g portions are taken for analysis. 1g portions should be sufficient to obtain reasonable repeatability for silver analysis.

Method of Preparation: Pulverized feldspar minerals and barren iron pyrites were blended with finely pulverized and screened, gold and silver-containing minerals. Once the powders were uniformly mixed the composite was placed into 748 wide-mouthed jars, each bearing a unique number. 30 jars were randomly selected from the packaging run and material from these jars was used for both homogeneity and consensus testing.


Homogeneity Assessment for Gold: An independent laboratory carried out all gold analyses by fire assay of 30g portions, using a gravimetric finish with a balance capable of reading to one microgram. Steps were taken to minimize laboratory method variation in order to better detect any variation in the reference material. Homogeneity Assessment Prior to Packaging 30 samples were removed at regular intervals from the prepared candidate reference material prior to packaging into 2.5 kg jars. The results of analysis of the 30 samples produced a coefficient of variation of 0.8%. Homogeneity Assessment After Packaging The contents of three randomly selected jars were compacted by vibration (to simulate the effect of freighting) and five samples removed successively from top to bottom from each of the three jars. In addition, five samples were removed from the last jar in the series. 30 samples were removed from the top of 30 jars randomly selected from the 748 jars in the batch. The results of analysis of the 50 samples produced a coefficient of variation of 1.0%. As the homogeneity testing was carried out using 30g analytical portions, the same degree of homogeneity cannot be guaranteed if smaller weights are taken for analysis.

Homogeneity Assessment for Silver:

Ten x 1g portions, taken from ten different jars, produced a coefficient of variation of 1.6 % when analysed together in the one batch by an independent laboratory. The method used was an aqua regia digest followed by AAS.

Analytical Methodology: Once homogeneity had been established, two sub-samples were submitted to a number of well-recognized laboratories in order to assign gold and silver values by consensus testing. The sub-samples were drawn from the 30 randomly selected jars and each laboratory received samples from two different jars. Indicative concentration ranges were given. Two laboratories used neutron activation and the remainder used fire assay for gold analysis. Most laboratories used an acid digest/instrumental detection procedure for silver.


30 sets of results were returned for gold and 22 sets for silver. Statistical analysis to identify outliers was carried out using the principles detailed in sections 7.3.2 – 7.3.4, ISO 5725-2: 1994. Assessment of each laboratory’s performance was carried out on the basis of z-scores, partly based on the concept described in ISO/IEC Guide 43-1. Details of the criteria used in these examinations are available on request. As a result of these statistical analyses, five sets of gold results and one set of silver results were excluded for the purpose of assigning gold and silver concentration values to this reference material. Recommended values were thus calculated from the average of the remaining n = 25 sets of replicate results for gold and n = 21 sets of replicate results for silver. The 95% confidence interval for each average was estimated using the formula:-

X ± ts/�n


Calculation of Certified Value (continued): (where X is the estimated average, s is the estimated standard deviation of the laboratory averages, and t is the 0.025 tail-value from Student’s t-distribution with n-1 degrees of freedom). The recommended values are provided at the beginning of the certificate in µg/g (ppm) units. A summary of the results used to calculate the recommended values are listed below and the names of the laboratories that submitted results are listed on page 5.

Legal Notice: This certificate and the reference material described in it have been prepared with due care and attention. However ROCKLABS Ltd, Malcolm Smith Reference Materials Ltd and Tim Ball Ltd accept no liability for any decisions or actions taken following the use of the reference material.

Summary of Results Used to Calculate Gold and Silver Values (not related to order of laboratories listed on page 5)

Statistical analysis of both homogeneity and consensus test results has been carried out by an independent statistician.

Gold (ppm) Silver (ppm)Sample 1 Sample 2 Average Sample 1 Sample 2 Average

1.695 1.674 1.685 18.5 17.0 17.751.75 1.67 1.710 18.1 18.0 18.051.75 1.68 1.715 18.3 18.7 18.501.73 1.73 1.730 18.9 19.0 18.951.74 1.74 1.740 19 19 19.01.73 1.78 1.755 19.1 19.1 19.101.78 1.74 1.760 19.1 19.2 19.15

1.745 1.776 1.761 19.25 19.20 19.2251.74 1.80 1.770 19.3 19.4 19.351.73 1.82 1.775 20 19 19.51.76 1.80 1.780 19 20 19.51.79 1.78 1.785 19.88 19.73 19.8051.81 1.78 1.795 20.1 19.8 19.95

1.800 1.819 1.810 20 20 20.01.810 1.825 1.818 20 20 20.01.83 1.83 1.830 20.2 20.1 20.151.85 1.83 1.840 20.6 20.1 20.351.85 1.85 1.850 22 20 21.01.86 1.88 1.870 21.8 20.3 21.051.87 1.87 1.870 22.7 20.0 21.351.87 1.88 1.875 21.8 21.4 21.60

1.871 1.902 1.8871.860 1.915 1.8881.92 1.88 1.9001.93 1.93 1.930

Average of 25 sets = 1.805 ppm Average of 21 sets = 19.68 ppmStandard deviation of 25 sets = 0.067 ppm Standard deviation of 21 sets = 1.02 ppm

Coefficient of variation = 3.7 % Coefficient of variation = 5.2 %95% Confidence interval for average = 0.028 ppm 95% Confidence interval for average = 0.46 ppm


Participating Laboratories Australia Amdel, Adelaide Amdel, Perth

Amdel, Kalgoorlie Becquerel Laboratories, Lucas Heights Genalysis Laboratory Services Pty Ltd, Perth SGS Analabs, Perth SGS Analabs, Townsville Standard and Reference Laboratories, Perth

Brazil Lakefield Geosol Limitada

Canada Acme Analytical Laboratories Ltd, British Columbia Activation Laboratories Ltd, Ontario ALS Chemex, British Columbia ALS Chemex Chimitec, Quebec Bourlamaque Assay Laboratories Ltd, Quebec SGS Lakefield Research Limited, Ontario

SGS XRAL Laboratories, Ontario

Ireland OMAC Laboratories Ltd

New Zealand Amdel New Zealand Ltd, Otago SGS New Zealand Ltd, Waihi

Russia Irgiredmet, Irkutsk Magadangeologia, Magadan Tsnigri, Moscow

South Africa Anglo American Research Laboratories (Pty) Ltd AngloGold, Vaal River AngloGold, West Wits Mintek, Analytical Services Division SGS Lakefield Research Africa (Pty) Ltd

United States of America ALS Chemex, Nevada Barrick Goldstrike Mines Inc, Nevada Newmont Mining Corporation, Nevada

References: For further information on the preparation and validation of this reference material please contact Malcolm Smith.



Certificate of Analysis, ROCKLABS Reference Material Si64. 9 March 2012. Page 1 of 6.

P.O Box 18-142, Glen Innes 1743 Auckland, New Zealand.

P 64 9 634 7696 F 64 9 634 6896 E [email protected]

www.rocklabs.com

World Leaders in Sample Preparation Equipment,

Automated Systems and Certified Reference Materials








Rocklabs Reference Materials


Auckland 0632

NEW ZEALAND


Telephone: +64 9 444 3534

Date of Certification: 9 March 2012










Supplier of Reference Material: ROCKLABS

P O Box 18 142

Glen Innes

Auckland 1743

NEW ZEALAND











%

SiO2 55.13

Al2O3 16.23

Na2O 4.87

K2O 4.46

CaO 3.65

MgO 3.40

TiO2 0.94

MnO 0.07

P2O5 0.22

Fe2O3 4.82

Fe 2.7

S 3.0

Intended Use:

This reference material is designed to be included with every


monitoring and assessment purposes.

Stability: The container (jar or sachet) should not be heated to

temperatures higher than 50 °C. Iron pyrites are likely to

oxidize in the air but tests have shown that the increase in

weight of an exposed reference material of similar matrix, in

the Auckland climate, is less than 0.1% per year.


pyrites were blended with finely pulverized and screened








An independent laboratory carried out gold analysis by fire assay of 30 g portions,





from each jar. In addition, five samples were removed from the last jar in the series.

A sample was also removed from the top of each of the 54 jars randomly selected

from the 2563 jars in the batch. The results of analysis of the 89 samples (randomly


produced a relative standard deviation of 1.2 %.






were given. All laboratories used fire assay for the gold analysis, with most using an

instrument finish and 3 using a gravimetric finish.







of these statistical analyses, nine sets of results were excluded for the purpose of




X ± ts/√n






submitted results are listed on page 5. The results are listed in increasing order of the

individual laboratory averages.

Statistical analysis of the consensus test results has been carried out by independent

statistician, Tim Ball.


Summary of Results Used to Calculate Gold Value (Listed in increasing order of individual laboratory averages)

Sample 1 Sample 2 Average1.726 1.702 1.714

1.723 1.720 1.7221.76 1.6845 1.722

1.733 1.714 1.724

1.710 1.745 1.728

1.701 1.754 1.7281.741 1.726 1.734

1.73 1.75 1.740

1.73 1.76 1.745

1.73 1.76 1.7451.770 1.734 1.752

1.740 1.770 1.755

1.731 1.783 1.7571.760 1.757 1.758

1.790 1.740 1.765

1.76 1.77 1.765

1.725 1.806 1.7661.78 1.76 1.770

1.76 1.78 1.770

1.768 1.775 1.7721.755 1.790 1.773

1.773 1.775 1.774

1.75 1.81 1.780

1.77 1.79 1.7801.780 1.790 1.785

1.784 1.794 1.789

1.800 1.780 1.790

1.790 1.800 1.7951.83 1.78 1.805

1.82 1.79 1.805

1.79 1.82 1.8051.82 1.80 1.810

1.81 1.81 1.810

1.809 1.822 1.816

1.825 1.825 1.8251.85 1.80 1.825

1.84 1.82 1.830

1.84 1.87 1.855

1.85 1.86 1.8551.859 1.860 1.860

1.910 1.880 1.895



Relative standard deviation = 2.4 %95% Confidence interval for average = 0.013 ppm

Gold (ppm)

Note: this standard deviation should not be used as a

basis to set control limits when plotting results from an

individual laboratory.



Australia ALS Minerals, Kalgoorlie

ALS Minerals, Perth

ALS Minerals, Townsville

Bureau Veritas Amdel, Adelaide

Bureau Veritas Amdel, Kalgoorlie

Intertek Genalysis Laboratory Services, Perth


Ultra Trace – Bureau Veritas, Perth

Burkina Faso ALS Minerals, Burkina Faso

Semafo Burkina Faso S.A.

Canada Acme Analytical Laboratories, Vancouver

ALS Minerals, Val d’Or

ALS Minerals, Vancouver

Loring Laboratories (Alberta) Ltd, Calgary

SGS Minerals Services, Lakefield

SGS Minerals Services, Vancouver

Techni-Lab S.G.B. Abitibi Inc/Actlabs, Québec

TSL Laboratories Inc, Saskatoon

Chile Acme Analytical Laboratories, Santiago

ALS Minerals, La Serena

Côte d’Ivoire Bureau Veritas Mineral Laboratories, Abidjan

Ireland OMAC Laboratories Ltd

Kyrgyz Republic Stewart Assay and Environmental Laboratories LLC, Kara-Balta

Mali ALS Minerals, Bamako

Namibia Bureau Veritas- Mineral Laboratories, Swakopmund

New Zealand SGS New Zealand Ltd, Otago

SGS New Zealand Ltd, Reefton

SGS New Zealand Ltd, Waihi

Peru ALS Minerals, Lima

Inspectorate Services Perú S.A.C., Callao

Minera Yanacocha SRL – Newmont, Lima

Romania ALS Minerals, Rosia Montana

Russia Irgiredmet Analytical Centre, Irkutsk

South Africa AB Analytical Laboratory Services, Boksburg

ALS Minerals, Modderfontein

AngloGold Ashanti, Vaal River Chemical Laboratory - Metallurgy

Gold Fields West Wits Analytical Laboratory

Performance Laboratories, Allanridge

Performance Laboratories, Barberton

Performance Laboratories, Randfontein

SGS South Africa (Pty) Ltd, Johannesburg

Turkey Acme Analitik Laboratuar Hizmetleri Ltd, Sirketi

ALS Minerals, Izmir

United Kingdom Inspectorate International, Essex

USA Acme Analytical Laboratories, Alaska

ALS Minerals, Reno

Barrick Goldstrike – Met Services

Inspectorate, Sparks


Zimbabwe Performance Laboratories, Ruwa

























this, we can provide a free Excel template that will produce sensible graphs, with

intelligently chosen limits, from the customer’s own data.

Legal Notice:


and attention. However ROCKLABS Ltd, Scott Technology Ltd and Tim Ball Ltd accept

no liability for any decisions or actions taken following the use of the reference material.

References:





Certificate of Analysis, ROCKLABS Reference Material Si42, 12 March 2008. Page 1 of 6.

161 Neilson Street, Auckland, New Zealand Email: [email protected]

Tel: +64 9 634 7696 Fax: +64 9 634 6896 Website: www.rocklabs.com Certificate of Analysis







Malcolm Smith Reference Materials Ltd


North Shore City 0632

NEW ZEALAND


Telephone: +64 9 444 3534











Supplier of Reference Material: ROCKLABS Ltd

P O Box 18 142

Auckland

NEW ZEALAND



Telephone: +64 9 634 7696









%

SiO2 57.48

Al2O3 16.55

Na2O 5.63

K2O 4.49

CaO 2.76

MgO 2.90

TiO2 0.79

MnO 0.06

P2O5 0.21

Fe2O3 4.14

Fe 2.7

S 3.0

Intended Use: This reference material is designed to be included with every


monitoring purposes.

Stability: The container (jar or sachet) and its contents should not be

heated to temperatures higher than 50 °C. Iron pyrites are

likely to oxidize in the air but tests have shown that the

increase in weight of an exposed reference material of similar

matrix, in the Auckland climate, is less than 0.1% per year.


pyrites were blended with finely pulverized and screened,








An independent laboratory carried out all gold analyses by fire assay of 30 g portions,



Homogeneity Assessment After Packaging



from each jar. In addition, samples were removed from the last jar in the series. A

sample was also removed from the top of each of the 48 jars randomly selected from

the 1609 jars in the batch. The results of analysis of the 83 samples (randomly


produced a coefficient of variation of 1.4 %.






were given. All laboratories used fire assay for the gold analysis.







of these statistical analyses, five sets of results were excluded for the purpose of




X ± ts/√n






submitted results are listed on page 5.


Summary of Results Used to Calculate Gold Value (not related to order of laboratories listed on page 5)

Gold (ppm)

Sample 1 Sample 2 Average

1.66 1.66 1.660

1.70 1.65 1.675

1.68 1.68 1.680

1.68 1.71 1.695

1.70 1.72 1.710

1.71 1.72 1.715

1.742 1.717 1.7295

1.730 1.739 1.7345

1.730 1.750 1.7400

1.72 1.77 1.745

1.750 1.740 1.7450

1.7450 1.7480 1.7465

1.750 1.760 1.755

1.74 1.79 1.765

1.73 1.82 1.775

1.780 1.779 1.7795

1.791 1.772 1.7810

1.785 1.783 1.7838

1.77 1.80 1.785

1.74 1.83 1.785

1.841 1.753 1.7970

1.795 1.800 1.7975

1.79 1.83 1.810

1.825 1.820 1.8225

1.804 1.843 1.8235

1.860 1.790 1.8250

1.8830 1.9165 1.8998



Coefficient of variation = 3.0 %

95% Confidence interval for average = 0.021 ppm

Note: this standard deviation should not be used as

a basis to set control limits when plotting results

from an individual laboratory.

Statistical analysis of both homogeneity and consensus test results has been carried

out by independent statistician, Tim Ball.



Australia Amdel Ltd, Adelaide

Amdel Laboratories Ltd, Perth

Amdel Laboratories Ltd, Kalgoorlie

Genalysis Laboratory Services Pty Ltd, Perth


SGS Townsville Minerals, Townsville

Standard and Reference Laboratories, Perth

Ultra Trace Analytical Laboratories, Perth

Canada Accurassay Laboratories, Ontario

Acme Analytical Laboratories Ltd, British Columbia

ALS Chemex, British Columbia

ALS Chemex, Quebec

Assayers Canada, British Columbia

Bourlamaque Assay Laboratories Ltd, Quebec

International Plasma Labs Ltd, British Columbia

Loring Laboratories Ltd, Alberta

SGS Minerals Services, Ontario

TSL Laboratories Inc, Saskatchewan

Chile Acme Analytical Laboratories S.A.

Kyrgyzstan Alex Stewart Assay and Environmental Laboratories Ltd

New Zealand Amdel NZ Ltd, Macraes, Otago

SGS Minerals, Waihi

Peru Minera Yanacocha SRL – Newmont

Russia Irgiredmet JSC, Irkutsk

Russian Academy of Science, Karelia

South Africa Anglo Research, Johannesburg

SGS South Africa Pty Ltd, Johannesburg

MINTEK: Analytical Services Division, Randburg

United States of America ALS Chemex, Nevada

Barrick Goldstrike Mines Inc, Nevada


Newmont Mining Corporation, Lone Tree Laboratory

























this more simply for themselves, we can provide a free Excel template that will produce

sensible graphs, with intelligently chosen limits, from the customer’s own data.

Legal Notice:


and attention. However ROCKLABS Ltd, Malcolm Smith Reference Materials Ltd and

Tim Ball Ltd accept no liability for any decisions or actions taken following the use of the

reference material.

References:





Certificate of Analysis, ROCKLABS Reference Material SI25, 13 March 2006. Page 1 of 6.


Reference Material SI25

Recommended Values and 95% Confidence Intervals Gold Concentration: 1.801 (+/- 0.018) µg/g Silver Concentration: 33.25 (+/- 0.61) µg/g

The above values apply only to product in jars or sachets which have an identification number within the following range: (The unique number range is not published on website).

Prepared and Certified By: Malcolm Smith BSc, FNZIC Malcolm Smith Reference Materials Ltd 40 Oakford Park Crescent Auckland 1311 NEW ZEALAND Telephone: +64 9 444 3534 Telefax: +64 9 444 7739 Email: [email protected]



Available Packaging: This reference material has been packed in wide-mouthed jars that contain 2.5kg of product. The contents of some jars may be subsequently repacked into sealed polyethylene sachets.

Origin of Reference Material: Feldspars and iron pyrites with minor quantities of finely divided gold and silver-containing minerals that have been screened to ensure there is no gold nugget effect.

Supplier of Reference Material: ROCKLABS Ltd P O Box 18 142 Auckland NEW ZEALAND Email: [email protected] Website: www.rocklabs.com

Description: The component minerals have been well mixed and a homogeneity test carried out after the entire batch was packaged into wide-mouthed jars to ascertain that the gold is evenly distributed throughout the reference material. There is


no soil component. The product contains crystalline quartz and therefore dust from it should not be inhaled.


(Uncertified Values) % SiO2 63.07

Al2O3 18.02 Na2O 7.86

K2O 3.65

CaO 0.24 MgO 0.16

TiO2 0.04

MnO 0.01 P2O5 0.11

Fe 3.0

S 2.9

Intended Use: This reference material is designed to be included with every batch of samples analysed and the results plotted for quality monitoring purposes.

Stability: The container (jar or sachet) and its contents should not be heated to temperatures higher than 50 °C. Iron pyrites are likely to oxidize in the air but tests have shown that the increase in weight of an exposed reference material of similar matrix, in the Auckland climate, is less than 0.1% per year.

Method of Preparation: Pulverized feldspar minerals and barren iron pyrites were blended with finely pulverized and screened, gold and silver-containing minerals. Once the powders were uniformly mixed the composite was placed into 1355 wide-mouthed jars, each bearing a unique number. 40 jars were randomly selected from the packaging run and material from these jars was used for both homogeneity and consensus testing.

Homogeneity Assessment for Gold: An independent laboratory carried out gold analysis by fire assay of 30g portions, using a gravimetric finish with a balance capable of reading to one microgram. Steps were taken to minimize laboratory method variation in order to better detect any variation in the reference material. Homogeneity Assessment After Packaging The contents of five of the randomly selected jars were compacted by vibration (to simulate the effect of freighting) and five samples removed successively from top to bottom from each of the five jars. In addition, five samples were removed from the last jar in the series. One sample was removed from the top of each of the 40 jars


randomly selected from the 1355 jars in the batch. The results of gold analysis of the 70 samples produced a coefficient of variation of 0.8%.

Analytical Methodology: Once homogeneity had been established, two sub-samples were submitted to a number of well-recognized laboratories in order to assign gold and silver values by consensus testing. The sub-samples were drawn from the 40 randomly selected jars and each laboratory received samples from two different jars. Indicative concentration ranges were given. All laboratories used fire assay for gold analysis and either acid digestion/instrumental or fire assay methods for silver.


29 sets of results for gold and 24 sets of results for silver were returned. Statistical analysis to identify outliers was carried out using the principles detailed in sections 7.3.2 – 7.3.4, ISO 5725-2: 1994. One set of silver results was excluded on the basis of this examination. Assessment of each laboratory’s performance for gold analysis was carried out on the basis of z-scores, partly based on the concept described in ISO/IEC Guide 43-1. Details of the criteria used in these examinations are available on request. As a result of both these statistical analyses, four sets of results were excluded for the purpose of assigning a gold concentration value to this reference material. The recommended values were thus calculated from the average of the n = 25 sets of replicate results for gold and n = 23 sets of replicate results for silver. The 95% confidence intervals were estimated using the formula:-

X ± ts/�n (where X is the estimated average, s is the estimated standard deviation of the laboratory averages, and t is the 0.025 tail-value from Student’s t-distribution with n-1 degrees of freedom). The recommended values for both gold and silver are provided at the beginning of the certificate in µg/g (ppm) units. Summaries of the results used to calculate the recommended values are listed on page 4 and the names of the laboratories that submitted results are listed on page 5.

Summary of Results Used to Calculate Gold and Silver Values (not related to order of laboratories listed on page 5)


Statistical analysis of both homogeneity and consensus test results has been carried out by independent statistician, Tim Ball.


Australia

Gold (ppm) Silver (ppm)Sample 1 Sample 2 Average Sample 1 Sample 2 Average

1.69 1.71 1.700 30 30 30.01.72 1.75 1.733 29.9 31.9 30.901.73 1.75 1.740 30.25 32.0 31.125

1.740 1.750 1.745 31.8 31.8 31.801.745 1.755 1.750 32.4 32.0 32.201.77 1.76 1.765 32.35 32.50 32.425

1.765 1.77 1.768 32.6 32.6 32.601.795 1.785 1.790 32.7 32.7 32.701.783 1.800 1.792 32.775 32.765 32.7701.82 1.78 1.800 33.1 33.2 33.151.80 1.80 1.800 33.0 33.5 33.25

1.797 1.803 1.800 34 33 33.51.818 1.783 1.801 34 33 33.51.81 1.80 1.805 33.90 33.80 33.850

1.800 1.820 1.810 33.2 34.6 33.901.81 1.82 1.816 34 34 34.01.83 1.81 1.820 34.25 34.25 34.250

1.830 1.815 1.823 34.0 35.0 34.501.845 1.820 1.833 34.5 34.5 34.501.86 1.82 1.840 34.44 34.95 34.6951.85 1.83 1.840 34.8 34.6 34.701.84 1.86 1.850 34 36 35.01.83 1.88 1.857 36 35 35.5

1.831 1.896 1.8641.85 1.90 1.875

Average of 25 sets = 1.801 ppm Average of 23 sets = 33.25 ppmStandard deviation of 25 sets = 0.044 ppm Standard deviation of 23 sets = 1.40 ppm

Coefficient of variation = 2.5% Coefficient of variation = 4.2%

95% Confidence interval for average = 0.018 ppm 95% Confidence interval for average = 0.61 ppm


ALS Chemex, Perth Amdel Ltd, Adelaide Amdel Laboratories Ltd, Perth

Amdel Ltd, Kalgoorlie Genalysis Laboratory Services Pty Ltd, Perth SGS Australia Pty Ltd, Perth SGS Australia Pty Ltd, Townsville Standard and Reference Laboratories, Perth Ultra Trace Analytical Laboratories, Perth

Canada Accurassay Laboratories, Ontario Acme Analytical Laboratories Ltd, British Columbia ALS Chemex, British Columbia ALS Chemex, Quebec Assayers Canada, British Columbia Bourlamaque Assay Laboratories Ltd, Quebec International Plasma Labs Ltd, British Columbia Loring Laboratories Ltd, Alberta TSL Laboratories Inc, Saskatchewan

Kyrgyzstan Alex Stewart Assay and Environmental Laboratories Ltd New Zealand Amdel Ltd, Otago SGS New Zealand Ltd, Waihi

Russia Irgiredmet, Irkutsk Norilsk Nickel, Trans-Polar Division Russian Academy of Science, Karelia

South Africa MINTEK, Analytical Science Division SGS Lakefield Research Africa (Pty) Ltd

United States of America ALS Chemex, Nevada Barrick Goldstrike Mines Inc, Nevada Newmont Mining Corporation, Nevada


Instructions and Recommendations for Use: Weigh out quantity usually used for analysis and analyze for gold and silver by normal procedures. Homogeneity testing has shown that consistent results are obtainable for gold when 30g portions are taken for analysis.

We quote a 95% confidence interval for our estimate of the declared values. The confidence intervals reflect our uncertainty in estimating the true values for the gold and silver contents of the reference material. The interval is chosen such that, if the same procedure as used here to estimate the declared value were used again and again, then 95% of the trials would give intervals that contained the true value. It is a reflection of how precise the trial has been in estimating the declared value. It does not reflect the variability any particular laboratory will experience in its own repetitive testing.

Some users in the past have misinterpreted the confidence interval as a guide as to how different an individual test result should be from the declared value. Some mistakenly use this interval to set limits for control charts on their own routine test results using the reference material. Such use inevitably leads to many apparent out-of-control points, leading to doubts about the laboratory’s testing, or of the reference material itself. A much better way of determining the laboratory performance for testing the reference material is to accumulate a history of the test results obtained, and plot them on a control chart. The appropriate centre line and control limits for this chart should be based on the average level and variability exhibited in the laboratory’s own data. This chart will provide a clear picture of the long-term stability or otherwise of the laboratory testing process, providing good clues as to the causes of any problems. To help our customers do this more simply for themselves, we can provide a free Excel template that will produce sensible graphs, with intelligently chosen limits, from the customer’s own data.

Legal Notice: This certificate and the reference material described in it have been prepared with due care and attention. However ROCKLABS Ltd, Malcolm Smith Reference Materials Ltd and Tim Ball Ltd accept no liability for any decisions or actions taken following the use of the reference material.

References: For further information on the preparation and validation of this reference material please contact Malcolm Smith.



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