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Certificate of Analysis, ROCKLABS Reference Material OxJ47, 13 March 2006. Page 1 of 6.
Certificate of Analysis
Reference Material OxJ47
Recommended Gold Concentration: 2.384 µg/g
95% Confidence Interval: +/- 0.020 µg/g
The above values apply only to product in jars or sachets which have an identification number
within the following range: 109 952 – 111 272.
Prepared and Certified By: Malcolm Smith BSc, FNZIC
Malcolm Smith Reference Materials Ltd
40 Oakford Park Crescent, Greenhithe,
Auckland 1311
NEW ZEALAND
Email: [email protected]
Telephone: +64 9 444 3534
Fax: +64 9 444 7739
Date of Certification: 13 March 2006
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: Feldspars 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
NEW ZEALAND
Email: [email protected]
Website: www.rocklabs.com
Telephone: +64 9 634 7696
Certificate of Analysis, ROCKLABS Reference Material OxJ47, 13 March 2006. Page 2 of 6.
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.
The approximate chemical composition is:
(Uncertified Values)
%
SiO2 66.63
Al2O3 19.13
Na2O 8.38
K2O 3.84
CaO 0.22
MgO 0.18
TiO2 0.03
MnO 0.00
P2O5 0.09
Fe2O3 0.53
L O I 0.39
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. The reference
material is stable, with weight changes of less than 0.5 % at
extremes of naturally occurring temperature and humidity
conditions.
Method of Preparation: Pulverized feldspar minerals were blended with finely
pulverized and screened, gold-containing minerals. Once the
powders were uniformly mixed the composite was placed into
1321 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.
Certificate of Analysis, ROCKLABS Reference Material OxJ47, 13 March 2006. Page 3 of 6.
Homogeneity Assessment:
An independent laboratory carried out all gold analyses by fire assay of 30 g 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 candidate reference material.
Homogeneity Assessment After Packaging
The contents of five 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 removed from the top of each of the 40 jars randomly selected from the
1321 jars in the batch. The results of analysis of the 70 samples (randomly ordered
and then consecutively numbered before being sent to the laboratory) produced a
coefficient of variation of 1.2 %.
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 40 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.
Calculation of Certified Value:
Results for gold were returned from 29 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 = 24 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.
Certificate of Analysis, ROCKLABS Reference Material OxJ47, 13 March 2006. Page 4 of 6.
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
2.245 2.250 2.248
2.318 2.294 2.306
2.33 2.34 2.333
2.31 2.37 2.340
2.33 2.37 2.349
2.345 2.355 2.350
2.370 2.355 2.363
2.39 2.36 2.373
2.360 2.385 2.373
2.37 2.39 2.380
2.374 2.395 2.385
2.42 2.35 2.385
2.36 2.42 2.390
2.41 2.37 2.390
2.40 2.40 2.400
2.390 2.414 2.402
2.41 2.40 2.405
2.40 2.41 2.405
2.42 2.42 2.420
2.38 2.48 2.430
2.417 2.463 2.440
2.42 2.47 2.445
2.45 2.44 2.445
2.445 2.460 2.453
Average of 24 sets = 2.384 ppm
Standard deviation of 24 sets = 0.048 ppm
Coefficient of variation = 2.0 %
95% Confidence interval for average = 0.020 ppm
Statistical analysis of both homogeneity and consensus test results has been carried
out by independent statistician, Tim Ball.
Certificate of Analysis, ROCKLABS Reference Material OxJ47, 13 March 2006. Page 5 of 6.
Participating Laboratories
Australia 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
Certificate of Analysis, ROCKLABS Reference Material OxJ47, 13 March 2006. Page 6 of 6.
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 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.
Certifying Officer Independent Statistician
M G Smith BSc, FNZIC Tim Ball BSc (Hons)
Certificate of Analysis, ROCKLABS Reference Material OxJ64, 23 October 2007. 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
Reference Material OxJ64
Recommended Gold Concentration: 2.366 µg/g
95% Confidence Interval: +/- 0.031 µg/g
The above values apply only to product in jars or sachets which have an identification number
within the following range: 150 346 – 151 884.
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: 23 October 2007
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: Basalt and feldspar minerals 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
NEW ZEALAND
Email: [email protected]
Website: www.rocklabs.com
Telephone: +64 9 634 7696
Certificate of Analysis, ROCKLABS Reference Material OxJ64, 23 October 2007. Page 2 of 6.
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 61.68
Al2O3 17.60
Na2O 6.78
K2O 3.36
CaO 2.51
MgO 2.68
TiO2 0.73
MnO 0.06
P2O5 0.23
Fe2O3 3.88
L O I 0.31
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. The reference
material is stable, with weight changes of less than 0.5 % at
extremes of naturally occurring temperature and humidity
conditions.
Method of Preparation: Pulverized basalt rock and feldspar minerals were blended
with finely pulverized and screened, gold-containing
minerals. Once the powders were uniformly mixed the
composite was placed into 1539 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.
Certificate of Analysis, ROCKLABS Reference Material OxJ64, 23 October 2007. Page 3 of 6.
Homogeneity Assessment:
An independent laboratory carried out all gold analyses by fire assay of 30 g portions,
using a gravimetric finish. Steps were taken to minimize laboratory method variation
in order to better detect any variation in the candidate reference material.
Homogeneity Assessment After Packaging
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 1539 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 coefficient of variation (COV) of 3.2 %. This unexpectedly high CoV
was due to one spuriously high result. Further samples were subsequently analyzed
from the jar that produced the high result as well as from adjacent jars, with no other
high results being obtained. The cause of this single high result is unknown. If the
one high result is omitted, the coefficient of variation of the remaining 82 results is
1.0%.
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.
Calculation of Certified Value:
Results for gold were returned from 31 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, four 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 = 27 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.
Certificate of Analysis, ROCKLABS Reference Material OxJ64, 23 October 2007. Page 4 of 6.
Summary of Results Used to Calculate Gold Value (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.
Gold (ppm)
Sample 1 Sample 2 Average
2.22 2.18 2.200
2.22 2.23 2.225
2.221 2.262 2.2415
2.31 2.29 2.300
2.293 2.310 2.3015
2.31 2.32 2.315
2.36 2.29 2.325
2.34 2.31 2.325
2.350 2.325 2.3375
2.33 2.36 2.345
2.369 2.324 2.3465
2.361 2.362 2.3615
2.40 2.34 2.370
2.34 2.40 2.370
2.36 2.38 2.370
2.314 2.434 2.3740
2.34 2.41 2.375
2.39 2.38 2.385
2.41 2.37 2.390
2.41 2.39 2.400
2.383 2.434 2.4085
2.43 2.39 2.410
2.455 2.465 2.4600
2.46 2.47 2.465
2.449 2.485 2.4670
2.417 2.520 2.4685
2.550 2.567 2.5585
Average of 27 sets = 2.366 ppm
Standard deviation of 27 sets = 0.079 ppm
Coefficient of variation = 3.3 %
95% Confidence interval for average = 0.031 ppm
Note: this standard deviation should not be used as
a basis to set control limits when plotting results
from an individual laboratory.
Certificate of Analysis, ROCKLABS Reference Material OxJ64, 23 October 2007. Page 5 of 6.
Participating Laboratories
Australia ALS Chemex, Perth
Amdel Ltd, Adelaide
Amdel Laboratories Ltd, Perth
Amdel Laboratories Ltd, Kalgoorlie
Genalysis Laboratory Services Pty Ltd, Perth
SGS Welshpool Minerals, Perth
SGS Townsville Minerals, Townsville
Standard and Reference Laboratories, Perth
Ultra Trace Analytical Laboratories, Perth
Canada ALS Chemex, British Columbia
ALS Chemex, Quebec
Assayers Canada, British Columbia
Bourlamaque Assay Laboratories Ltd, Quebec
International Plasma Labs Ltd, British Columbia
Loring Laboratories, Alberta
SGS Minerals Services, Ontario
TSL Laboratories Inc, Saskatchewan
Chile ACME Analytical Laboratories Ltda
Kyrgyzstan Alex Stewart Assay and Environmental Laboratories Ltd
New Zealand SGS Minerals, Waihi
Peru Minera Yanacocha SRL – Newmont
Russia Irgiredmet, Irkutsk
Russian Academy of Science, Karelia
South Africa Anglo Research
MINTEK: Analytical Services Division
SGS Lakefield Research Africa
United States of America ALS Chemex, Nevada
Barrick Goldstrike Mines Inc, Nevada
Newmont Mining Corporation, Carlin Laboratory
Newmont Mining Corporation, Lone Tree Laboratory
Newmont Mining Corporation, Twin Creeks Laboratory
Certificate of Analysis, ROCKLABS Reference Material OxJ64, 23 October 2007. Page 6 of 6.
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 OxJ120. 26 November 2013. 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
Certificate of Analysis
Reference Material OxJ120
Recommended Gold Concentration: 2.365 µg/g
95% Confidence Interval: +/- 0.017 µg/g
The above values apply only to product in jars or sachets which have an identification number
within the following range: 352 342– 356 598.
Prepared and Certified By: Brett Coombridge, M.Phil. Chemistry
Rocklabs Reference Materials
P.O. Box 316056
Wairau Valley Post Centre
Auckland 0760
NEW ZEALAND
Email: [email protected]
Telephone: +64 9 444 3534
Date of Certification: 26 November 2013
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: Basalt and feldspar minerals 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
P O Box 18 142
Glen Innes
Auckland 1743
NEW ZEALAND
Email: [email protected]
Website: www.rocklabs.com
Certificate of Analysis, ROCKLABS Reference Material OxJ120. 26 November 2013. Page 2 of 6
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 59.36
Al2O3 17.11
Na2O 4.97
K2O 5.59
CaO 3.33
MgO 3.18
TiO2 0.88
MnO 0.06
P2O5 0.23
Fe2O3 4.71
L O I 0.24
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) should not be heated to
temperatures higher than 50 °C. The reference material is
stable, with weight changes of less than 0.5 % at extremes of
naturally occurring temperature and humidity conditions.
Method of Preparation: Pulverized basalt rock and feldspar minerals were blended
with finely pulverized and screened gold-containing minerals.
Once the powders were uniformly mixed the composite was
placed into 4257 wide-mouthed jars, each bearing a unique
number. 75 jars were randomly selected from the packaging
run and material from these jars was used for both
homogeneity and consensus testing.
Homogeneity Assessment:
Sampling (described below) was performed by Rocklabs Reference Materials and an
independent laboratory carried out gold analysis of the samples by fire assay of 30 g
portions, using an ICP finish. Steps were taken to minimize laboratory method
variation to better detect any variation in the candidate reference material.
Certificate of Analysis, ROCKLABS Reference Material OxJ120. 26 November 2013. Page 3 of 6
Homogeneity: A sample was removed from the top of each of the 75 jars randomly
selected from the 4257 jars in the batch. The results of analysis of the 75 samples
(randomly ordered then consecutively numbered before being sent to the laboratory)
produced a relative standard deviation of 1.1%.
Settling: The contents of 6 randomly selected jars were compacted by vibration (to
simulate the effect of freighting) and 5 samples were removed successively from top
to bottom from each jar. In addition, 5 samples were removed from the last jar in the
series. No top to bottom gradation in the gold values was observed neither was there
a significant difference between the last jar and the other jars.
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 75 randomly selected jars and each
laboratory received samples from two different jars.
Participating laboratories analysed the samples by fire assay followed by either
gravimetric or instrument finish (AAS or ICP). Indicative concentration ranges were
provided. Some laboratories analysed the samples twice using both methods. In this
situation both sets of results were presented separately, and included in the statistical
analysis. The amount of sample used in the analyses varied between laboratories
(range 15 - 50g).
Calculation of Certified Value:
As some laboratories returned results for two different methods, 58 sets of gold
results were returned from 54 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, 5 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 = 53 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.
Certificate of Analysis, ROCKLABS Reference Material OxJ120. 26 November 2013. Page 4 of 6
Summary of Results Used to Calculate Gold Value (Listed in increasing order of individual laboratory averages)
Note: Neither the Standard deviation nor the Confidence interval should be
used as a basis to set control limits when plotting individual laboratory results.
See notes under "Instructions and Recommendations for Use" (pg 6)
Sample 1 Sample 2 Set Average2.256 2.258 2.257
2.27 2.25 2.26
2.28 2.24 2.26
2.26 2.29 2.275
2.333 2.225 2.279
2.28 2.31 2.295
2.32 2.28 2.3
2.31 2.29 2.3
2.27 2.34 2.305
2.28 2.33 2.305
2.255 2.363 2.309
2.350 2.270 2.31
2.35 2.32 2.335
2.32 2.35 2.335
2.35 2.32 2.335
2.340 2.335 2.3375
2.26 2.42 2.34
2.328 2.361 2.3445
2.32 2.37 2.345
2.389 2.312 2.3505
2.357 2.345 2.351
2.37 2.34 2.355
2.254 2.458 2.356
2.374 2.340 2.357
2.360 2.355 2.3575
2.36 2.36 2.36
2.34 2.38 2.36
2.350 2.371 2.3605
2.36 2.37 2.365
2.34 2.39 2.365
2.348 2.385 2.3665
2.385 2.350 2.3675
2.36 2.38 2.37
2.346 2.404 2.375
2.31 2.44 2.375
2.330 2.425 2.3775
2.410 2.345 2.3775
2.43 2.33 2.38
2.37 2.40 2.385
2.38 2.40 2.39
2.42 2.36 2.39
2.41 2.38 2.395
2.37 2.42 2.395
2.40 2.41 2.405
2.422 2.414 2.418
2.47 2.37 2.42
2.40 2.45 2.425
2.44 2.42 2.43
2.50 2.42 2.46
2.46 2.47 2.465
2.52 2.51 2.515
2.518 2.527 2.5225
2.59 2.54 2.565
Average of 53 sets = 2.365 ppm
Standard deviation of 53 sets = 0.063 ppmRelative standard deviation = 2.7 %95% Confidence interval for average: = +/- 0.017 ppm
Gold (ppm)
Certificate of Analysis, ROCKLABS Reference Material OxJ120. 26 November 2013. Page 5 of 6
Participating Laboratories
Australia ALS Minerals, Burnie
ALS Minerals, Kalgoorlie
ALS Minerals, Orange
ALS Minerals, Perth
ALS Minerals, Townsville
Bureau Veritas Amdel, Adelaide
Bureau Veritas Amdel, Kalgoorlie
Intertek Genalysis Laboratory Services, 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
Bourlamaque, Quebec
Loring Laboratories (Alberta) Ltd, Calgary
SGS Minerals Services, Lakefield, Ontario
SGS Minerals Services, Vancouver
Techni-Lab S.G.B. Abitibi Inc/Actlabs, Val d’Or
Techni-Lab S.G.B. Abitibi Inc/Actlabs, Ste-Germaine-Boule
TSL Laboratories Inc, Saskatoon
Chile Acme Analytical Laboratories, Santiago
Côte d’Ivoire Bureau Veritas Mineral Laboratories, Abidjan
Ghana ALS Minerals, Kumasi
SGS Performance Lab, Obuasi AngloGold
Ireland ALS Minerals, Loughrea
Kyrgyz Republic Stewart Assay and Environmental Laboratories LLC, Kara-Balta
Laos ALS Geochemistry, Vientiane
Mali ALS Minerals, Bamako
Mongolia ALS Minerals, Ulaanbaatar
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
Acme, Inspectorate M & M, Rustenburg
ALS Minerals, Edenvale
SibanyeGold, Driefontein Operations
Performance Laboratories, Barberton
Performance Laboratories, Randfontein
Performance Laboratories, Allanridge
Turkey Acme Analitik Laboratuar Hizmetleri Ltd, Sirketi
ALS Minerals, Izmir
USA ALS Minerals, Reno
Barrick Goldstrike – Met Services, Nevada
Inspectorate, Sparks
Newmont Mining Corporation, Carlin
Newmont Mining Corporation, Lone Tree
Newmont Mining Corporation, Twin Creeks
Zimbabwe Performance Laboratories, Ruwa
Certificate of Analysis, ROCKLABS Reference Material OxJ120. 26 November 2013. Page 6 of 6
Instructions and Recommendations for Use:
Weigh out quantity usually used for analysis, and analyse 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, 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, Scott Technology 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 Brett Coombridge.
Certifying Officer Independent Statistician
Brett Coombridge (M.Phil. Chemistry) Tim Ball BSc (Hons)
Certificate of Analysis, ROCKLABS Reference Material OxJ95, 7 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
Certificate of Analysis
Reference Material OxJ95
Recommended Gold Concentration: 2.337 µg/g
95% Confidence Interval: +/- 0.018 µg/g
The above values apply only to product in jars or sachets which have an identification number
within the following range: 260 772 – 263 228.
Prepared and Certified By: Malcolm Smith BSc, FNZIC
Rocklabs Reference Materials
40 Oakford Park Crescent, Greenhithe
Auckland 0632
NEW ZEALAND
Email: [email protected]
Telephone: +64 9 444 3534
Date of Certification: 7 March 2012
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: Basalt and feldspar minerals 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
P O Box 18 142
Glen Innes
Auckland 1743
NEW ZEALAND
Email: [email protected]
Website: www.rocklabs.com
Certificate of Analysis, ROCKLABS Reference Material OxJ95, 7 March 2012. Page 2 of 6.
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 58.18
Al2O3 17.17
Na2O 5.08
K2O 4.66
CaO 3.94
MgO 3.63
TiO2 1.01
MnO 0.07
P2O5 0.25
Fe2O3 5.33
L O I 0.51
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) should not be heated to
temperatures higher than 50 °C. The reference material is
stable, with weight changes of less than 0.5 % at extremes of
naturally occurring temperature and humidity conditions.
Method of Preparation: Pulverized basalt rock and feldspar minerals were blended
with finely pulverized and screened, gold-containing
minerals. Once the powders were uniformly mixed the
composite was placed into 2457 wide-mouthed jars, each
bearing a unique number. 54 jars were randomly selected
from the packaging run and material from these jars was used
for both homogeneity and consensus testing.
Certificate of Analysis, ROCKLABS Reference Material OxJ95, 7 March 2012. Page 3 of 6.
Homogeneity Assessment:
An independent laboratory carried out gold analysis by fire assay of 30 g portions,
using a gravimetric finish. Steps were taken to minimize laboratory method variation
in order to better detect any variation in the candidate reference material.
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 54 jars randomly selected
from the 2457 jars in the batch. The results of analysis of the 89 samples (randomly
ordered and then consecutively numbered before being sent to the laboratory)
produced a relative standard deviation of 1.0 %.
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 54 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 3 using a gravimetric finish.
Calculation of Certified Value:
Results for gold were returned from 50 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, eight 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 = 42 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.
Certificate of Analysis, ROCKLABS Reference Material OxJ95, 7 March 2012. Page 4 of 6.
Summary of Results Used to Calculate Gold Value (Listed in increasing order of individual laboratory averages)
Sample 1 Sample 2 Average2.07 2.22 2.145
2.190 2.210 2.2002.27 2.26 2.265
2.28 2.25 2.2652.30 2.29 2.2952.24 2.35 2.295
2.283 2.312 2.2982.33 2.27 2.300
2.31 2.29 2.3002.314 2.314 2.3142.29 2.34 2.315
2.360 2.271 2.3152.285 2.360 2.323
2.283 2.364 2.3242.315 2.332 2.3242.35 2.30 2.325
2.28 2.37 2.3252.33 2.33 2.330
2.33 2.33 2.3302.348 2.317 2.3332.320 2.348 2.334
2.35 2.32 2.3352.32 2.36 2.3402.350 2.335 2.343
2.342 2.347 2.3442.343 2.353 2.348
2.345 2.36 2.3532.351 2.357 2.3542.357 2.357 2.357
2.37 2.36 2.3652.360 2.375 2.368
2.38 2.36 2.3702.461 2.288 2.3752.42 2.34 2.380
2.480 2.2855 2.3832.410 2.365 2.388
2.40 2.39 2.3952.39 2.40 2.3952.40 2.42 2.410
2.420 2.404 2.4122.46 2.44 2.450
2.46 2.45 2.455Average of 42 sets = 2.337 ppm
Standard deviation of 42 sets = 0.057 ppm
Relative standard deviation = 2.4 %95% Confidence interval for average = 0.018 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.
Certificate of Analysis, ROCKLABS Reference Material OxJ95, 7 March 2012. Page 5 of 6.
Participating Laboratories
Australia ALS Minerals, Kalgoorlie
ALS Minerals, Perth
ALS Minerals, Townsville
Bureau Veritas Amdel, Adelaide
Bureau Veritas Amdel, Kalgoorlie
Intertek Genalysis Laboratory Services, Perth
SGS Minerals 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
Newmont Mining Corporation, Carlin Laboratory
Zimbabwe Performance Laboratories, Ruwa
Certificate of Analysis, ROCKLABS Reference Material OxJ95, 7 March 2012. Page 6 of 6.
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, 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, Scott Technology 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 OxJ80, 19 April, 2010. Page 1 of 6.
Certificate of Analysis
Reference Material OxJ80
Recommended Gold Concentration: 2.331 µg/g
95% Confidence Interval: +/- 0.014 µg/g
The above values apply only to product in jars or sachets which have an identification number
within the following range: 204 652 – 206 295.
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: Basalt and feldspar minerals 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
Email: [email protected]
Website: www.rocklabs.com
Telephone: +64 9 634 7696
Certificate of Analysis, ROCKLABS Reference Material OxJ80, 19 April, 2010. Page 2 of 6.
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 58.31
Al2O3 16.98
Na2O 4.32
K2O 6.04
CaO 4.43
MgO 2.61
TiO2 0.78
MnO 0.06
P2O5 0.23
Fe2O3 4.15
L O I 1.65
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. The reference
material is stable, with weight changes of less than 0.5 % at
extremes of naturally occurring temperature and humidity
conditions.
Method of Preparation: Pulverized basalt rock and feldspar minerals were blended
with finely pulverized and screened, gold-containing
minerals. Once the powders were uniformly mixed the
composite was placed into 1644 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 a gravimetric finish. Steps were taken to minimize laboratory method variation
in order to better detect any variation in the candidate reference material.
Certificate of Analysis, ROCKLABS Reference Material OxJ80, 19 April, 2010. Page 3 of 6.
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 1644 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 1.2 %.
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, seven 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 = 36 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.
Certificate of Analysis, ROCKLABS Reference Material OxJ80, 19 April, 2010. Page 4 of 6.
Summary of Results Used to Calculate Gold Value (Listed in increasing order of individual laboratory averages)
Gold (ppm)
Sample 1 Sample 2 Average
2.270 2.240 2.255
2.27 2.27 2.270
2.244 2.302 2.273
2.27 2.28 2.275
2.290 2.267 2.279
2.29 2.27 2.280
2.28 2.29 2.285
2.314 2.268 2.291
2.30 2.31 2.305
2.31 2.30 2.305
2.30 2.31 2.305
2.32 2.30 2.310
2.326 2.295 2.311
2.31 2.32 2.315
2.33 2.31 2.320
2.321 2.323 2.322
2.342 2.305 2.324
2.32 2.33 2.325
2.34 2.31 2.325
2.336 2.321 2.329
2.31 2.35 2.330
2.34 2.32 2.330
2.33 2.34 2.335
2.34 2.35 2.345
2.36 2.35 2.355
2.390 2.325 2.358
2.38 2.340 2.360
2.36 2.37 2.365
2.38 2.37 2.375
2.37 2.38 2.375
2.39 2.38 2.385
2.41 2.36 2.385
2.38 2.40 2.390
2.40 2.40 2.400
2.410 2.390 2.400
2.41 2.43 2.420
Average of 36 sets = 2.331 ppm
Standard deviation of 36 sets = 0.042 ppm
Relative standard deviation = 1.8 %
95% Confidence interval for average = 0.014 ppm
Note: this standard deviation should not be used as
a basis to set control limits when plotting results
from an individual laboratory.
Certificate of Analysis, ROCKLABS Reference Material OxJ80, 19 April, 2010. Page 5 of 6.
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
Certificate of Analysis, ROCKLABS Reference Material OxJ80, 19 April, 2010. Page 6 of 6.
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 OxJ68, 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
Reference Material OxJ68
Recommended Gold Concentration: 2.342 µg/g
95% Confidence Interval: +/- 0.025 µg/g
The above values apply only to product in jars or sachets which have an identification number
within the following range: 157 264 – 158 836.
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: 12 March 2008
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: Basalt and feldspar minerals 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
NEW ZEALAND
Email: [email protected]
Website: www.rocklabs.com
Telephone: +64 9 634 7696
Certificate of Analysis, ROCKLABS Reference Material OxJ68, 12 March 2008. Page 2 of 6.
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 60.82
Al2O3 17.72
Na2O 6.18
K2O 4.43
CaO 2.75
MgO 2.65
TiO2 0.75
MnO 0.06
P2O5 0.25
Fe2O3 3.93
L O I 0.36
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. The reference
material is stable, with weight changes of less than 0.5 % at
extremes of naturally occurring temperature and humidity
conditions.
Method of Preparation: Pulverized basalt rock and feldspar minerals were blended
with finely pulverized and screened, gold-containing
minerals. Once the powders were uniformly mixed the
composite was placed into 1573 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.
Certificate of Analysis, ROCKLABS Reference Material OxJ68, 12 March 2008. Page 3 of 6.
Homogeneity Assessment:
An independent laboratory carried out all gold analyses by fire assay of 30 g portions,
using a gravimetric finish. Steps were taken to minimize laboratory method variation
in order to better detect any variation in the candidate reference material.
Homogeneity Assessment After Packaging
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 1573 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 coefficient of variation (COV) of 1.1 %.
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.
Calculation of Certified Value:
Results for gold were returned from 32 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, four 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 = 28 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.
Certificate of Analysis, ROCKLABS Reference Material OxJ68, 12 March 2008. Page 4 of 6.
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
2.19 2.20 2.195
2.270 2.205 2.2375
2.27 2.27 2.270
2.30 2.25 2.275
2.297 2.275 2.2860
2.309 2.294 2.3015
2.31 2.30 2.305
2.320 2.295 2.3073
2.315 2.300 2.3075
2.310 2.315 2.3125
2.290 2.340 2.3150
2.26 2.37 2.315
2.32 2.34 2.330
2.30 2.37 2.335
2.340 2.350 2.3450
2.34 2.35 2.345
2.338 2.357 2.3475
2.345 2.380 2.3625
2.335 2.405 2.3700
2.343 2.398 2.3705
2.3590 2.3915 2.3753
2.37 2.39 2.380
2.37 2.42 2.395
2.42 2.41 2.415
2.45 2.39 2.420
2.47 2.38 2.425
2.4330 2.4495 2.4413
2.462 2.522 2.4920
Average of 28 sets = 2.342 ppm
Standard deviation of 28 sets = 0.064 ppm
Coefficient of variation = 2.7 %
95% Confidence interval for average = 0.025 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.
Certificate of Analysis, ROCKLABS Reference Material OxJ68, 12 March 2008. Page 5 of 6.
Participating Laboratories
Australia Amdel Ltd, Adelaide
Amdel Laboratories Ltd, Perth
Amdel Laboratories Ltd, Kalgoorlie
Genalysis Laboratory Services Pty Ltd, Perth
SGS Minerals Services, 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, Carlin Laboratory
Newmont Mining Corporation, Lone Tree Laboratory
Certificate of Analysis, ROCKLABS Reference Material OxJ68, 12 March 2008. Page 6 of 6.
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 OxJ36, 29 July 2004. Page 1 of 5.
Certificate of Analysis
Reference Material OxJ36
Recommended Gold Concentration: 2.398 µg/g 95% Confidence Interval: +/- 0.031 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, Greenhithe, Auckland 1311 NEW ZEALAND Email: [email protected] Telephone: +64 9 444 3534 Fax: +64 9 444 7739
Date of Certification: 29 July 2004
Certificate Status: Original
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 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 NEW ZEALAND Email: [email protected] Telephone: +64 9 634 7696 Fax: +64 9 634 6896
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
Certificate of Analysis, ROCKLABS Reference Material OxJ36, 29 July 2004. Page 2 of 5.
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.
The approximate chemical composition is:
(Uncertified Values) % SiO2 67.84
Al2O3 19.42
Na2O 10.89
K2O 0.29
CaO 0.33
MgO 0.14
TiO2 0.04
MnO 0.01
P2O5 0.08
Fe2O3 0.56
L O I 0.40
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. The reference material is stable, with weight changes of less than 0.5% at extremes of naturally occurring temperature and humidity conditions.
Instructions 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. Homogeneity cannot be guaranteed if smaller weights are taken for analysis.
Method of Preparation: Pulverized feldspar minerals were blended with finely pulverized and screened, gold-containing minerals. Once the powders were uniformly mixed the composite was placed into 749 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: 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
Certificate of Analysis, ROCKLABS Reference Material OxJ36, 29 July 2004. Page 3 of 5.
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 0.6%. 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 749 jars in the batch. The results of analysis of the 50 samples produced a coefficient of variation of 0.7%. 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.
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 30 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.
Calculation of Certified Value:
27 sets of results for gold were returned from 27 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, three 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 = 24 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.
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.
Certificate of Analysis, ROCKLABS Reference Material OxJ36, 29 July 2004. Page 4 of 5.
Summary of Results Used to Calculate Gold Value (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.
Participating Laboratories
Australia Amdel Laboratories Ltd, Adelaide Amdel Ltd, Perth
Amdel Ltd, Kalgoorlie Genalysis Laboratory Services Pty Ltd, Perth SGS Australia Pty Ltd, Perth SGS Australia Pty Ltd, Townsville
Gold (ppm)Sample 1 Sample 2 Average
2.217 2.273 2.2452.195 2.325 2.2602.342 2.279 2.3112.33 2.34 2.3352.33 2.37 2.3502.35 2.35 2.3502.35 2.35 2.350
2.320 2.390 2.3552.379 2.351 2.3652.30 2.46 2.3802.40 2.40 2.4002.40 2.40 2.4002.37 2.43 2.4002.40 2.43 2.4152.41 2.43 2.4202.40 2.45 2.4252.54 2.33 2.435
2.441 2.449 2.4452.45 2.46 2.455
2.467 2.456 2.4622.47 2.46 2.465
2.475 2.480 2.4782.466 2.495 2.4812.580 2.548 2.564
Average of 24 sets = 2.398 ppmStandard deviation of 24 sets = 0.073 ppm
Coefficient of variation = 3.0 %95% Confidence interval for average = 0.031 ppm
Certificate of Analysis, ROCKLABS Reference Material OxJ36, 29 July 2004. Page 5 of 5.
Standard and Reference Laboratories, Perth
Brazil Lakefield Geosol Laboratorios Ltda
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
Ireland OMAC Laboratories Ltd
New Zealand Amdel NZ Ltd, Otago SGS New Zealand Ltd, Waihi
Russia Irgiredmet, Irkutsk Magadangeologia, Magadan Norilsk Nickel, Trans-Polar division Russian Academy of Science, Karelia Tsnigri, Moscow
South Africa Anglo American Research Laboratories AngloGold Ashanti West Wits SGS Lakefield Research Africa
United States of America 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.
Certifying Officer Independent Statistician
M G Smith BSc, FNZIC Tim Ball BSc (Hons)