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i n f o @o re .c o m .a u w w w .o re a s .c o m

CERTIFICATE OF ANALYSIS FOR

CERTIFIED REFERENCE MATERIAL

OREAS 292
Gold-Antimony Ore (Costerfield, VIC, Australia)

Document: COA-1628-OREAS292-R1 19-September-2022

(Template:BUP-70-10-01 Rev:2.0)
 TABLE OF CONTENTS

INTRODUCTION ...............................................................................................................6
SOURCE MATERIAL .........................................................................................................7
PERFORMANCE GATES ..................................................................................................7
COMMINUTION AND HOMOGENISATION PROCEDURES ............................................8
PHYSICAL PROPERTIES .................................................................................................8
ANALYTICAL PROGRAM..................................................................................................8
STATISTICAL ANALYSIS ..................................................................................................9
Standard Deviation intervals ...................................................................................9
Certified Values and their uncertainty intervals .......................................................9
Homogeneity Evaluation .........................................................................................12
PREPARER AND SUPPLIER ............................................................................................15
PARTICIPATING LABORATORIES ...................................................................................15
METROLOGICAL TRACEABILITY ....................................................................................19
COMMUTABILITY .............................................................................................................19
INTENDED USE ................................................................................................................19
MINIMUM SAMPLE SIZE ..................................................................................................20
PERIOD OF VALIDITY & STORAGE INSTRUCTIONS .....................................................20
INSTRUCTIONS FOR HANDLING & CORRECT USE ......................................................21
LEGAL NOTICE .................................................................................................................21
DOCUMENT HISTORY .....................................................................................................22
QMS ACCREDITATION.....................................................................................................22
CERTIFYING OFFICER.....................................................................................................22
REFERENCES ..................................................................................................................22

LIST OF TABLES

Table 1. Certified Values and Performance Gates for OREAS 292. .................................... 3
Table 2. Indicative Values for OREAS 292. ......................................................................... 5
Table 3. Physical properties of OREAS 292. ....................................................................... 8
Table 4. 95% Uncertainty & Tolerance Limits for OREAS 292. ......................................... 10
Table 5. Neutron Activation Analysis of Au (in ppm) on 20 x 85mg subsamples. .............. 13

LIST OF FIGURES

Figure 1. Au by Fire Assay in OREAS 292 ........................................................................ 16

Figure 2. Au by aqua regia digestion in OREAS 292 ......................................................... 17
Figure 3. Sb by peroxide fusion with ICP finish in OREAS 292 ......................................... 18

COA-1628-OREAS292-R1 Page: 2 of 23
 Table 1. Certified Values and Performance Gates for OREAS 292.
Absolute Standard Deviations Relative Standard Deviations 5% window
Certified
Constituent
Value 2SD 2SD 3SD 3SD
1SD 1RSD 2RSD 3RSD Low High
Low High Low High
Pb Fire Assay
Au, ppm 11.06 0.353 10.36 11.77 10.00 12.12 3.19% 6.38% 9.58% 10.51 11.62
Aqua Regia Digestion (sample weights 10-50g)
Au, ppm 9.70 0.691 8.32 11.09 7.63 11.78 7.12% 14.24% 21.36% 9.22 10.19
Peroxide Fusion ICP
Sb, wt.% 4.54 0.217 4.11 4.98 3.89 5.19 4.77% 9.54% 14.32% 4.32 4.77
4-Acid Digestion
Ag, ppm 0.760 0.098 0.565 0.955 0.467 1.052 12.84% 25.67% 38.51% 0.722 0.798
Al, wt.% 6.76 0.341 6.08 7.44 5.74 7.78 5.04% 10.08% 15.12% 6.42 7.10
As, ppm 495 74 346 644 271 718 15.05% 30.10% 45.15% 470 519
Ba, ppm 549 33 484 615 451 647 5.96% 11.93% 17.89% 522 577
Be, ppm 2.53 0.172 2.18 2.87 2.01 3.05 6.81% 13.62% 20.43% 2.40 2.66
Bi, ppm 0.55 0.051 0.45 0.66 0.40 0.71 9.26% 18.52% 27.79% 0.53 0.58
Ca, wt.% 0.594 0.029 0.535 0.652 0.506 0.681 4.91% 9.83% 14.74% 0.564 0.623
Cd, ppm 0.067 0.015 0.038 0.096 0.023 0.111 21.83% 43.66% 65.49% 0.064 0.070
Ce, ppm 68 11 45 90 34 101 16.49% 32.99% 49.48% 64 71
Co, ppm 11.5 1.7 8.0 14.9 6.3 16.7 15.12% 30.23% 45.35% 10.9 12.0
Cr, ppm 105 12 81 130 68 142 11.67% 23.35% 35.02% 100 110
Cs, ppm 13.6 0.91 11.8 15.4 10.9 16.3 6.65% 13.30% 19.95% 12.9 14.3
Cu, ppm 58 4.7 49 68 44 72 8.05% 16.11% 24.16% 55 61
Dy, ppm 2.75 0.36 2.03 3.47 1.67 3.83 13.14% 26.29% 39.43% 2.61 2.89
Er, ppm 1.62 0.17 1.28 1.96 1.11 2.13 10.56% 21.11% 31.67% 1.54 1.70
Eu, ppm 0.95 0.10 0.76 1.14 0.66 1.24 10.12% 20.25% 30.37% 0.90 1.00
Fe, wt.% 3.40 0.207 2.99 3.82 2.78 4.02 6.09% 12.19% 18.28% 3.23 3.57
Ga, ppm 17.0 1.17 14.7 19.4 13.5 20.5 6.84% 13.69% 20.53% 16.2 17.9
Gd, ppm 3.69 0.350 2.99 4.39 2.64 4.74 9.48% 18.97% 28.45% 3.51 3.88
Ge, ppm 0.33 0.05 0.23 0.43 0.18 0.48 14.97% 29.94% 44.92% 0.32 0.35
Hf, ppm 3.27 0.250 2.77 3.77 2.52 4.02 7.63% 15.26% 22.89% 3.11 3.44
Ho, ppm 0.54 0.08 0.38 0.69 0.30 0.77 14.83% 29.66% 44.49% 0.51 0.56
In, ppm 0.062 0.007 0.049 0.075 0.042 0.081 10.57% 21.15% 31.72% 0.059 0.065
K, wt.% 2.87 0.139 2.60 3.15 2.46 3.29 4.82% 9.64% 14.47% 2.73 3.02
La, ppm 35.3 5.1 25.1 45.6 20.0 50.7 14.50% 29.00% 43.50% 33.6 37.1
Li, ppm 24.1 9.3 5.4 42.8 0.0 52.1 38.70% 77.41% 116.11 22.9 25.3
%
Lu, ppm 0.25 0.04 0.17 0.32 0.13 0.36 15.46% 30.93% 46.39% 0.23 0.26
Mg, wt.% 1.32 0.058 1.20 1.43 1.15 1.49 4.36% 8.72% 13.08% 1.25 1.38
Mn, wt.% 0.098 0.006 0.086 0.110 0.079 0.116 6.31% 12.61% 18.92% 0.093 0.103
Na, wt.% 0.369 0.016 0.338 0.401 0.322 0.416 4.26% 8.51% 12.77% 0.351 0.388
Nd, ppm 30.0 2.59 24.8 35.1 22.2 37.7 8.64% 17.28% 25.91% 28.5 31.4
Ni, ppm 37.8 4.1 29.6 46.1 25.4 50.2 10.92% 21.84% 32.76% 36.0 39.7
P, wt.% 0.049 0.005 0.039 0.059 0.034 0.063 10.14% 20.27% 30.41% 0.046 0.051
Pb, ppm 46.9 5.1 36.6 57.1 31.5 62.3 10.94% 21.88% 32.81% 44.5 49.2
Pr, ppm 7.94 0.734 6.47 9.40 5.73 10.14 9.25% 18.50% 27.75% 7.54 8.33
Rb, ppm 168 10 148 189 138 199 6.02% 12.03% 18.05% 160 177
Re, ppm < 0.002 IND IND IND IND IND IND IND IND IND IND
SI unit equivalents: ppm (parts per million; 1 x 106) ≡ mg/kg ≡ µg/g ≡ 0.0001 wt.%.
Note 1: intervals may appear asymmetric due to rounding.
Note 2: the number of decimal places quoted does not imply accuracy of the certified value to this level but are given to
minimise rounding errors when calculating 2SD and 3SD windows.

COA-1628-OREAS292-R1 Page: 3 of 23
 Table 1. continued.
Absolute Standard Deviations Relative Standard Deviations 5% window
Certified
Constituent
Value 2SD 2SD 3SD 3SD
1SD 1RSD 2RSD 3RSD Low High
Low High Low High
4-Acid Digestion continued
S, wt.% 2.09 0.085 1.92 2.26 1.84 2.35 4.05% 8.10% 12.14% 1.99 2.20
Sb, wt.% 3.52 1.29 0.95 6.10 0.00 7.38 36.46% 72.93% 109.39 3.35 3.70
%
Sc, ppm 12.5 0.81 10.9 14.1 10.1 15.0 6.46% 12.92% 19.38% 11.9 13.2
Se, ppm 10.1 1.2 7.7 12.4 6.5 13.6 11.70% 23.39% 35.09% 9.6 10.6
Sm, ppm 5.64 0.489 4.66 6.62 4.17 7.11 8.67% 17.34% 26.01% 5.36 5.92
Sn, ppm 3.12 0.54 2.03 4.20 1.48 4.75 17.48% 34.96% 52.44% 2.96 3.27
Sr, ppm 153 8 136 169 127 178 5.49% 10.98% 16.47% 145 160
Ta, ppm 0.58 0.10 0.38 0.79 0.27 0.89 17.64% 35.27% 52.91% 0.55 0.61
Tb, ppm 0.45 0.08 0.30 0.61 0.22 0.69 17.29% 34.58% 51.87% 0.43 0.47
Te, ppm 0.058 0.025 0.008 0.108 0.000 0.133 42.74% 85.48% 128.21 0.055 0.061
%
Th, ppm 14.5 1.5 11.5 17.6 10.0 19.1 10.42% 20.83% 31.25% 13.8 15.3
Tl, ppm 0.87 0.14 0.60 1.15 0.46 1.29 15.80% 31.60% 47.40% 0.83 0.92
Tm, ppm 0.23 0.04 0.16 0.30 0.12 0.33 15.55% 31.10% 46.64% 0.22 0.24
U, ppm 2.53 0.190 2.15 2.91 1.96 3.10 7.52% 15.04% 22.55% 2.40 2.66
V, ppm 56 20 17 95 0 115 34.89% 69.79% 104.68 53 59
%
Y, ppm 14.8 2.7 9.5 20.1 6.9 22.8 17.86% 35.72% 53.58% 14.1 15.6
Yb, ppm 1.59 0.21 1.17 2.01 0.96 2.22 13.21% 26.43% 39.64% 1.51 1.67
Zn, ppm 105 12 82 129 71 140 10.96% 21.91% 32.87% 100 111
Zr, ppm 108 8 91 125 83 133 7.81% 15.62% 23.43% 103 114
Aqua Regia Digestion
Ag, ppm 0.739 0.051 0.637 0.842 0.586 0.893 6.90% 13.80% 20.70% 0.702 0.776
Al, wt.% 1.24 0.111 1.02 1.46 0.91 1.57 8.95% 17.91% 26.86% 1.18 1.30
As, ppm 488 66 357 620 291 686 13.50% 26.99% 40.49% 464 513
Ba, ppm 136 14 108 165 93 180 10.56% 21.11% 31.67% 130 143
Be, ppm 1.05 0.14 0.78 1.33 0.64 1.46 12.96% 25.92% 38.89% 1.00 1.11
Bi, ppm 0.62 0.038 0.54 0.69 0.50 0.73 6.20% 12.41% 18.61% 0.59 0.65
Ca, wt.% 0.576 0.038 0.501 0.652 0.463 0.689 6.55% 13.09% 19.64% 0.547 0.605
Cd, ppm 0.067 0.011 0.046 0.089 0.035 0.099 15.87% 31.73% 47.60% 0.064 0.071
Ce, ppm 32.5 3.9 24.6 40.3 20.7 44.2 12.10% 24.19% 36.29% 30.8 34.1
Co, ppm 12.5 0.66 11.2 13.8 10.5 14.5 5.30% 10.60% 15.90% 11.9 13.1
Cr, ppm 38.2 5.6 27.1 49.3 21.5 54.9 14.56% 29.12% 43.67% 36.3 40.1
Cs, ppm 5.04 0.83 3.38 6.70 2.55 7.53 16.49% 32.98% 49.47% 4.79 5.29
Cu, ppm 62 2.6 57 67 54 70 4.19% 8.38% 12.57% 59 65
Fe, wt.% 3.27 0.194 2.89 3.66 2.69 3.86 5.92% 11.85% 17.77% 3.11 3.44
Ga, ppm 3.55 0.55 2.45 4.66 1.89 5.21 15.55% 31.10% 46.66% 3.37 3.73
Ge, ppm 0.083 0.012 0.058 0.107 0.046 0.119 14.91% 29.83% 44.74% 0.078 0.087
Hg, ppm 0.15 0.02 0.12 0.19 0.11 0.20 10.65% 21.29% 31.94% 0.15 0.16
In, ppm 0.038 0.003 0.032 0.044 0.029 0.048 8.37% 16.75% 25.12% 0.036 0.040
K, wt.% 0.572 0.044 0.485 0.659 0.441 0.703 7.62% 15.23% 22.85% 0.543 0.601
La, ppm 16.2 2.2 11.7 20.6 9.5 22.8 13.70% 27.40% 41.10% 15.4 17.0
Li, ppm 12.0 0.99 10.0 14.0 9.0 14.9 8.23% 16.45% 24.68% 11.4 12.6
Mg, wt.% 1.02 0.036 0.94 1.09 0.91 1.12 3.59% 7.18% 10.77% 0.96 1.07
Mn, wt.% 0.101 0.005 0.090 0.111 0.085 0.117 5.22% 10.43% 15.65% 0.096 0.106
SI unit equivalents: ppm (parts per million; 1 x 106) ≡ mg/kg; wt.% (weight per cent) ≡ % (mass fraction).
Note 1: intervals may appear asymmetric due to rounding.
Note 2: the number of decimal places quoted does not imply accuracy of the certified value to this level but are given to
minimise rounding errors when calculating 2SD and 3SD windows.

COA-1628-OREAS292-R1 Page: 4 of 23
 Table 1. continued.
Absolute Standard Deviations Relative Standard Deviations 5% window
Certified
Constituent
Value 2SD 2SD 3SD 3SD
1SD 1RSD 2RSD 3RSD Low High
Low High Low High
Aqua Regia Digestion continued
Mo, ppm 1.32 0.128 1.06 1.58 0.93 1.70 9.74% 19.49% 29.23% 1.25 1.38
Na, wt.% 0.031 0.002 0.027 0.035 0.025 0.037 6.23% 12.46% 18.69% 0.029 0.032
Ni, ppm 39.0 2.38 34.3 43.8 31.9 46.2 6.10% 12.19% 18.29% 37.1 41.0
P, wt.% 0.046 0.004 0.038 0.054 0.034 0.059 9.08% 18.15% 27.23% 0.044 0.048
Pb, ppm 41.1 8.7 23.7 58.6 15.0 67.3 21.19% 42.38% 63.58% 39.1 43.2
Rb, ppm 32.2 3.09 26.0 38.4 22.9 41.5 9.59% 19.19% 28.78% 30.6 33.8
Re, ppm 0.001 0.000 0.000 0.002 0.000 0.002 38.31% 76.63% 114.94 0.001 0.001
%
S, wt.% 2.12 0.079 1.96 2.28 1.88 2.36 3.73% 7.46% 11.19% 2.01 2.23
Sb, wt.% 4.61 0.237 4.13 5.08 3.90 5.32 5.14% 10.28% 15.42% 4.38 4.84
Sc, ppm 4.97 0.247 4.48 5.47 4.23 5.71 4.96% 9.92% 14.89% 4.72 5.22
Se, ppm 8.73 1.46 5.81 11.65 4.35 13.12 16.73% 33.46% 50.19% 8.30 9.17
Sn, ppm 0.84 0.14 0.56 1.11 0.42 1.25 16.57% 33.14% 49.71% 0.80 0.88
Sr, ppm 113 7 100 127 93 134 6.03% 12.07% 18.10% 108 119
Ta, ppm < 0.01 IND IND IND IND IND IND IND IND IND IND
Tl, ppm 0.29 0.03 0.23 0.35 0.19 0.38 10.90% 21.81% 32.71% 0.27 0.30
U, ppm 1.06 0.100 0.86 1.26 0.76 1.36 9.39% 18.79% 28.18% 1.01 1.11
V, ppm 16.0 2.2 11.5 20.5 9.3 22.8 14.00% 28.00% 42.01% 15.2 16.8
Y, ppm 7.01 0.217 6.58 7.44 6.36 7.66 3.09% 6.19% 9.28% 6.66 7.36
Zn, ppm 107 3 102 112 99 115 2.51% 5.01% 7.52% 102 112
SI unit equivalents: ppm (parts per million; 1 x 106) ≡ mg/kg; wt.% (weight per cent) ≡ % (mass fraction).
Note 1: intervals may appear asymmetric due to rounding.
Note 2: the number of decimal places quoted does not imply accuracy of the certified value to this level but are given to
minimise rounding errors when calculating 2SD and 3SD windows.

Table 2. Indicative Values for OREAS 292.

Constituent Unit Value Constituent Unit Value Constituent Unit Value
Pb Fire Assay
Pd ppb <5 Pt ppb <5
Peroxide Fusion ICP
Al wt.% 7.03 Ga ppm 12.6 S wt.% 2.09
As ppm 619 K wt.% 2.92 Sc ppm 13.2
Ba ppm 595 La ppm 37.6 Si wt.% 28.15
Be ppm <5 Li ppm <5 Sn ppm < 10
Bi ppm <5 Mg wt.% 1.36 Sr ppm 140
Ca wt.% 0.693 Mn wt.% 0.112 Ti wt.% 0.380
Cd ppm < 0.5 Mo ppm 3.10 V ppm 69
Co ppm 18.5 Nb ppm <5 W ppm 65
Cr ppm 150 Ni ppm 39.1 Y ppm 26.3
Cu ppm 91 P wt.% 0.057 Zn ppm 122
Peroxide Fusion ICP continued
Fe wt.% 3.70 Pb ppm 45.8
SI unit equivalents: ppb (parts per billion; 1 x109)≡ µg/kg; ppm (parts per million; 1 x 106) ≡ mg/kg; wt.% (weight per cent)
≡ % (mass fraction).
Note: the number of significant figures reported is not a reflection of the level of certainty of stated values. They are
instead an artefact of ORE’s in-house CRM-specific LIMS.

COA-1628-OREAS292-R1 Page: 5 of 23
 Table 2. continued.
Constituent Unit Value Constituent Unit Value Constituent Unit Value
4-Acid Digestion
Hg ppm 0.19 Nb ppm 5.81 W ppm 2.05
Mo ppm 1.00 Ti wt.% 0.216
Aqua Regia Digestion
B ppm 18.3 Nb ppm 0.20 Th ppm 4.79
Dy ppm 1.57 Nd ppm 11.7 Ti wt.% 0.007
Er ppm 0.82 Pd ppb < 10 Tm ppm 0.11
Eu ppm 0.54 Pr ppm 2.87 W ppm 0.66
Gd ppm 2.37 Pt ppb 1.75 Yb ppm 0.77
Hf ppm 0.16 Sm ppm 2.79 Zr ppm 8.24
Ho ppm 0.30 Tb ppm 0.31
Lu ppm 0.11 Te ppm 0.076
Borate Fusion XRF
Al2O3 wt.% 13.39 MgO wt.% 2.27 SiO2 wt.% 60.24
CaO wt.% 0.839 MnO wt.% 0.141 SO3 wt.% 5.13
Fe2O3 wt.% 5.24 P2O5 wt.% 0.138 TiO2 wt.% 0.635
K2O wt.% 3.56 Sb wt.% 4.77
Thermogravimetry
LOI1000 wt.% 6.72
Infrared Combustion
C wt.% 1.14 S wt.% 2.11
Laser Ablation ICP-MS
Ag ppm 0.900 Hf ppm 4.48 Sm ppm 5.87
As ppm 588 Ho ppm 0.99 Sn ppm 3.60
Ba ppm 583 In ppm 0.050 Sr ppm 150
Be ppm 2.50 La ppm 38.3 Ta ppm 1.05
Bi ppm 0.65 Lu ppm 0.39 Tb ppm 0.86
Cd ppm 0.13 Mn wt.% 0.102 Te ppm < 0.2
Ce ppm 74 Mo ppm 1.70 Th ppm 15.6
Co ppm 13.9 Nb ppm 12.7 Ti wt.% 0.375
Cr ppm 114 Nd ppm 34.1 Tl ppm 0.70
Cs ppm 13.4 Ni ppm 45.0 Tm ppm 0.40
Cu ppm 63 Pb ppm 55 U ppm 2.89
Dy ppm 4.75 Pr ppm 8.74 V ppm 85
Er ppm 2.74 Rb ppm 169 W ppm 8.00
Eu ppm 1.09 Re ppm 0.065 Y ppm 27.2
Ga ppm 17.1 Sb wt.% 4.79 Yb ppm 2.92
Gd ppm 5.32 Sc ppm 12.9 Zn ppm 108
Ge ppm 1.70 Se ppm <5 Zr ppm 168
SI unit equivalents: ppm (parts per million; 1 x 106) ≡ mg/kg; wt.% (weight per cent) ≡ % (mass fraction).
Note: the number of significant figures reported is not a reflection of the level of certainty of stated values. They are
instead an artefact of ORE’s in-house CRM-specific LIMS.

INTRODUCTION

OREAS reference materials are intended to provide a low-cost method of evaluating and
improving the quality of analysis of geological samples. To the geologist they provide a
means of implementing quality control in analytical data sets generated in exploration from
the grass roots level through to prospect evaluation, and in grade control at mining
operations. To the analyst they provide an effective means of calibrating analytical

COA-1628-OREAS292-R1 Page: 6 of 23
equipment, assessing new techniques and routinely monitoring in-house procedures.
OREAS reference materials enable users to successfully achieve process control of these
tasks because the observed variance from repeated analysis has its origin almost
exclusively in the analytical process rather than the reference material itself. In evaluating
laboratory performance with this CRM, the section headed ‘Instructions for correct use’
should be read carefully.

Table 1 provides performance gate intervals for the certified values, Table 2 shows indicative
values, Table 3 provides some indicative physical properties and Table 4 presents the 95%
expanded uncertainty and tolerance limits for all certified values. Tabulated results of all
analytes together with uncorrected means, medians, standard deviations, relative standard
deviations and per cent deviation of lab means from the corrected mean of means (PDM3)
are presented in the detailed certification data for this CRM (OREAS 292-
DataPack.1.2.220901_141016.xlsx).

Results are also presented in scatter plots for gold by fire assay, gold by aqua regia digestion,
and antimony by peroxide fusion (Figures 1 to 3, respectively) together with ±3SD (magenta)
and ±5% (yellow) control lines and certified value (green line). Accepted individual results are
coloured blue and individual and dataset outliers are identified in red and violet, respectively.

SOURCE MATERIAL

OREAS 292 was prepared from a sample of high-grade gold-antimony ore with a minor
addition of barren metasediment. The ore was sourced from the Costerfield Operation
(owned by Mandalay Resources Ltd) located approximately 10km northeast of the town of
Heathcote in Victoria, Australia.

PERFORMANCE GATES
Table 1 above shows intervals calculated for two and three standard deviations. As a guide
these intervals may be regarded as warning or rejection for multiple 2SD outliers, or rejection
for individual 3SD outliers in QC monitoring, although their precise application should be at
the discretion of the QC manager concerned (also see ‘Intended Use’ section below).
Westgard Rules extend the basics of single-rule QC monitoring using multi-rules (for more
information visit www.westgard.com/mltirule.htm). A second method utilises a 5% window
calculated directly from the certified value.

Standard deviation is also shown in relative percent for one, two and three relative standard
deviations (1RSD, 2RSD and 3RSD) to facilitate an appreciation of the magnitude of these
numbers and a comparison with the 5% window. Caution should be exercised when
concentration levels approach lower limits of detection of the analytical methods employed
as performance gates calculated from standard deviations tend to be excessively wide
whereas those determined by the 5% method are too narrow. One approach used at
commercial laboratories is to set the acceptance criteria at twice the detection level (DL) ±
10%.
I.e., Certified Value ± 10% ± 2DL [1].

COA-1628-OREAS292-R1 Page: 7 of 23
 COMMINUTION AND HOMOGENISATION PROCEDURES

The material constituting OREAS 292 was prepared in the following manner:
• Drying the source materials to constant mass at 85 degrees Celsius;
• Crushing and multi-stage milling of the ore to 100% passing 30 microns;
• Crushing and multi-stage milling of the barren metasediment to >98% minus 75 microns;
• Preliminary homogenisation;
• Check assaying of the ore material;
• Blending the ore and barren materials in a specific ratio to achieve target grades;
• Packaging in 60g units under nitrogen in laminated foil pouches.

PHYSICAL PROPERTIES

OREAS 292 was tested at ORE Research & Exploration Pty Ltd’s onsite facility for various
physical properties. Table 3 presents these findings that should be used for informational
purposes only.

Table 3. Physical properties of OREAS 292.

Bulk Density (g/L) Moisture% Munsell Notation‡ Munsell Color‡

913 0.60 N5 Medium Gray

‡The Munsell Rock Color Chart helps geologists and archeologists communicate with colour more
effectively by cross-referencing ISCC-NBS colour names with unique Munsell alpha-numeric colour
notations for rock colour samples.

ANALYTICAL PROGRAM
Twenty-two commercial analytical laboratories participated in the program to certify the
elements reported in Table 1. The following methods were employed:
• Au by 25-50g fire assay with AAS (14 laboratories) and ICP-OES (5 laboratories)
finish;
• Au by 15-30g aqua regia digestion with ICP-MS (9 laboratories), AAS (2
laboratories) and ICP-OES (1 laboratory) finish;
• Sb by peroxide fusion with ICP-OES (11 laboratories) and ICP-MS (2 laboratories)
finish and one laboratory used pressed powder pellet with XRF finish;
• Full ICP-OES and MS elemental suites by 4-acid digestion (up to 18 laboratories
depending on the element);
• Full ICP-OES and MS elemental suites by aqua regia digestion (up to 19
laboratories depending on the element);
• Instrumental neutron activation analysis (INAA) for Au on 20 x 85mg subsamples to
confirm homogeneity undertaken by the Australian Nuclear Science and Technology
Organisation (ANSTO) located in Lucas Heights, NSW, Australia.

For the round robin program, twenty 800g test units were taken at predetermined intervals
during the bagging stage, immediately following homogenisation and are considered
representative of the entire prepared batch. Six 110g pulp samples were submitted to each
laboratory for analysis. The samples received by each laboratory were obtained by taking

COA-1628-OREAS292-R1 Page: 8 of 23
two 110g samples from each of three separate 800g test units. This format enabled nested
ANOVA treatment of the results to evaluate homogeneity, i.e., to ascertain whether
between-unit variance is greater than within-unit variance.

STATISTICAL ANALYSIS

Standard Deviation intervals (see Table 1) provide an indication of a level of performance

that might reasonably be expected from a laboratory being monitored by this CRM in a
QA/QC program. They take into account errors attributable to measurement uncertainty and
CRM variability. For an effective CRM the contribution of the latter should be negligible in
comparison to measurement errors. The Standard Deviation values include all sources of
measurement uncertainty: between-lab variance, within-run variance (precision errors) and
CRM variability.

The SD for each analyte’s certified value is calculated from the same filtered data set used
to determine the certified value, i.e., after removal of all individual, lab dataset (batch) and
3SD outliers (single iteration). These outliers can only be removed after the absolute
homogeneity of the CRM has been independently established, i.e., the outliers must be
confidently deemed to be analytical rather than arising from inhomogeneity of the CRM.

The standard deviation is then calculated for each analyte from the pooled accepted
analyses generated from the certification program.

Indicative (uncertified) values (Table 2) are present where the number of laboratories
reporting a particular analyte is insufficient (< 5) to support certification or where inter-
laboratory consensus is poor.

Certified Values and their uncertainty intervals (Table 4) have been determined for each
analyte following removal of individual, laboratory dataset (batch) and 3SD outliers (single
iteration).

For individual outliers within a laboratory batch the z-score test is used in combination with
a second method that determines the per cent deviation of the individual value from the
batch median. Outliers in general are selected on the basis of z-scores > 2.5 and with per
cent deviations (i) > 3 and (ii) more than three times the average absolute per cent deviation
for the batch. In certain instances, statistician’s prerogative has been employed in
discriminating outliers. Each laboratory data set mean is tested for outlying status based on
z-score discrimination and rejected if > 2.5. After individual and laboratory data set (batch)
outliers have been eliminated a non-iterative 3 standard deviation filter is applied, with those
values lying outside this window also relegated to outlying status.

Certified Values are the means of accepted laboratory means after outlier filtering and are the
present best estimate of the true value. The INAA data (see Table 5) is omitted from
determination of the certified value for Au and is used solely for the calculation of Tolerance
Limits and homogeneity evaluation (see ‘Homogeneity Evaluation’ section below).

95% Expanded Uncertainty provides a 95% probability that the true value of the analyte
under consideration lies between the upper and lower limits and is calculated according to
the method in the ISO Guides [6,15]. All known or suspected sources of bias have been
investigated or taken into account. The 95% Expanded Uncertainty should not be used
as control limits for laboratory performance.

COA-1628-OREAS292-R1 Page: 9 of 23
 Table 4. 95% Uncertainty & Tolerance Limits for OREAS 292.
Certified 95% Expanded Uncertainty 95% Tolerance Limits
Constituent
Value Low High Low High
Pb Fire Assay
Au, Gold (ppm) 11.06 10.90 11.22 11.01* 11.11*
Aqua Regia Digestion (sample weights 10-50g)
Au, Gold (ppm) 9.70 9.20 10.21 9.66* 9.75*
Peroxide Fusion ICP
Sb, Antimony (wt.%) 4.54 4.33 4.75 4.47 4.62
4-Acid Digestion
Ag, Silver (ppm) 0.760 0.665 0.855 0.722 0.797
Al, Aluminium (wt.%) 6.76 6.46 7.06 6.55 6.98
As, Arsenic (ppm) 495 448 541 479 510
Ba, Barium (ppm) 549 524 574 532 566
Be, Beryllium (ppm) 2.53 2.33 2.73 2.35 2.71
Bi, Bismuth (ppm) 0.55 0.50 0.61 0.53 0.58
Ca, Calcium (wt.%) 0.594 0.566 0.621 0.575 0.612
Cd, Cadmium (ppm) 0.067 0.042 0.092 IND IND
Ce, Cerium (ppm) 68 60 75 64 71
Co, Cobalt (ppm) 11.5 10.4 12.5 10.9 12.0
Cr, Chromium (ppm) 105 96 115 101 109
Cs, Caesium (ppm) 13.6 12.9 14.3 12.9 14.3
Cu, Copper (ppm) 58 55 62 56 60
Dy, Dysprosium (ppm) 2.75 2.19 3.31 2.55 2.95
Er, Erbium (ppm) 1.62 1.37 1.87 IND IND
Eu, Europium (ppm) 0.95 0.78 1.11 IND IND
Fe, Iron (wt.%) 3.40 3.26 3.54 3.32 3.49
Ga, Gallium (ppm) 17.0 16.0 18.1 16.3 17.8
Gd, Gadolinium (ppm) 3.69 3.20 4.18 3.42 3.96
Ge, Germanium (ppm) 0.33 0.26 0.41 0.27 0.40
Hf, Hafnium (ppm) 3.27 3.04 3.50 3.14 3.41
Ho, Holmium (ppm) 0.54 0.40 0.67 IND IND
In, Indium (ppm) 0.062 0.052 0.071 0.056 0.067
K, Potassium (wt.%) 2.87 2.77 2.97 2.79 2.96
La, Lanthanum (ppm) 35.3 31.9 38.8 33.9 36.8
Li, Lithium (ppm) 24.1 19.0 29.2 22.3 25.9
Lu, Lutetium (ppm) 0.25 0.20 0.29 0.23 0.26
Mg, Magnesium (wt.%) 1.32 1.27 1.37 1.29 1.35
Mn, Manganese (wt.%) 0.098 0.094 0.102 0.096 0.100
SI unit equivalents: ppm (parts per million; 1 x
106) ≡ mg/kg; wt.% (weight per cent) ≡ % (mass fraction).
Note: intervals may appear asymmetric due to rounding.
*Gold Tolerance Limits for typical 30g fire assay and 25g aqua regia digestion methods are determined from 20 x 85mg
INAA results and the Sampling Constant (Ingamells & Switzer, 1973).
Note: intervals may appear asymmetric due to rounding.
IND = indeterminate (due to limited reading resolution of the methods employed).

COA-1628-OREAS292-R1 Page: 10 of 23
 Table 4. continued.
Certified 95% Expanded Uncertainty 95% Tolerance Limits
Constituent
Value Low High Low High
4-Acid Digestion continued
Na, Sodium (wt.%) 0.369 0.355 0.383 0.357 0.382
Nd, Neodymium (ppm) 30.0 26.7 33.2 28.1 31.8
Ni, Nickel (ppm) 37.8 35.3 40.4 36.1 39.6
P, Phosphorus (wt.%) 0.049 0.046 0.051 0.047 0.050
Pb, Lead (ppm) 46.9 43.5 50.2 44.9 48.9
Pr, Praseodymium (ppm) 7.94 6.82 9.06 7.40 8.47
Rb, Rubidium (ppm) 168 159 178 162 174
Re, Rhenium (ppm) < 0.002 IND IND IND IND
S, Sulphur (wt.%) 2.09 2.01 2.18 2.04 2.15
Sb, Antimony (wt.%) 3.52 2.64 4.41 3.35 3.70
Sc, Scandium (ppm) 12.5 11.9 13.2 12.0 13.0
Se, Selenium (ppm) 10.1 8.6 11.6 9.3 10.9
Sm, Samarium (ppm) 5.64 4.95 6.33 5.17 6.11
Sn, Tin (ppm) 3.12 2.74 3.49 2.90 3.33
Sr, Strontium (ppm) 153 145 160 149 157
Ta, Tantalum (ppm) 0.58 0.43 0.74 0.51 0.66
Tb, Terbium (ppm) 0.45 0.37 0.53 0.42 0.48
Te, Tellurium (ppm) 0.058 0.000 0.123 IND IND
Th, Thorium (ppm) 14.5 13.3 15.8 14.0 15.1
Tl, Thallium (ppm) 0.87 0.78 0.97 0.82 0.92
Tm, Thulium (ppm) 0.23 0.16 0.29 IND IND
U, Uranium (ppm) 2.53 2.35 2.70 2.41 2.65
V, Vanadium (ppm) 56 45 67 52 60
Y, Yttrium (ppm) 14.8 13.0 16.7 13.9 15.7
Yb, Ytterbium (ppm) 1.59 1.34 1.84 IND IND
Zn, Zinc (ppm) 105 98 112 102 109
Zr, Zirconium (ppm) 108 102 114 104 113
Aqua Regia Digestion
Ag, Silver (ppm) 0.739 0.694 0.785 0.717 0.762
Al, Aluminium (wt.%) 1.24 1.17 1.31 1.20 1.27
As, Arsenic (ppm) 488 446 531 474 503
Ba, Barium (ppm) 136 127 146 132 141
Be, Beryllium (ppm) 1.05 0.94 1.16 0.99 1.12
Bi, Bismuth (ppm) 0.62 0.58 0.66 0.59 0.64
Ca, Calcium (wt.%) 0.576 0.546 0.607 0.559 0.593
Cd, Cadmium (ppm) 0.067 0.058 0.077 IND IND
Ce, Cerium (ppm) 32.5 28.6 36.3 31.2 33.7
SI unit equivalents: ppm (parts per million; 1 x
106) ≡ mg/kg; wt.% (weight per cent) ≡ % (mass fraction).
Note: intervals may appear asymmetric due to rounding.
IND = indeterminate (due to limited reading resolution of the methods employed).

COA-1628-OREAS292-R1 Page: 11 of 23
 Table 4. continued.
Certified 95% Expanded Uncertainty 95% Tolerance Limits
Constituent
Value Low High Low High
Aqua Regia Digestion continued
Co, Cobalt (ppm) 12.5 11.7 13.3 12.0 13.0
Cr, Chromium (ppm) 38.2 35.2 41.2 36.8 39.6
Cs, Caesium (ppm) 5.04 4.44 5.64 4.85 5.23
Cu, Copper (ppm) 62 59 65 60 64
Fe, Iron (wt.%) 3.27 3.15 3.40 3.20 3.34
Ga, Gallium (ppm) 3.55 3.14 3.97 3.39 3.71
Ge, Germanium (ppm) 0.083 0.058 0.107 IND IND
Hg, Mercury (ppm) 0.15 0.13 0.18 IND IND
In, Indium (ppm) 0.038 0.032 0.044 0.033 0.043
K, Potassium (wt.%) 0.572 0.545 0.599 0.554 0.590
La, Lanthanum (ppm) 16.2 14.5 17.8 15.6 16.8
Li, Lithium (ppm) 12.0 11.1 12.9 11.4 12.5
Mg, Magnesium (wt.%) 1.02 0.99 1.04 0.99 1.04
Mn, Manganese (wt.%) 0.101 0.098 0.104 0.098 0.103
Mo, Molybdenum (ppm) 1.32 1.16 1.48 1.26 1.38
Na, Sodium (wt.%) 0.031 0.029 0.032 0.029 0.032
Ni, Nickel (ppm) 39.0 37.2 40.9 38.1 40.0
P, Phosphorus (wt.%) 0.046 0.043 0.049 0.044 0.048
Pb, Lead (ppm) 41.1 35.9 46.4 39.1 43.2
Rb, Rubidium (ppm) 32.2 29.7 34.7 30.7 33.7
Re, Rhenium (ppm) 0.001 0.001 0.001 IND IND
S, Sulphur (wt.%) 2.12 2.05 2.19 2.06 2.18
Sb, Antimony (wt.%) 4.61 4.43 4.79 4.50 4.71
Sc, Scandium (ppm) 4.97 4.72 5.23 4.69 5.26
Se, Selenium (ppm) 8.73 7.56 9.91 8.20 9.26
Sn, Tin (ppm) 0.84 0.72 0.95 IND IND
Sr, Strontium (ppm) 113 109 118 111 116
Ta, Tantalum (ppm) < 0.01 IND IND IND IND
Tl, Thallium (ppm) 0.29 0.26 0.32 0.27 0.31
U, Uranium (ppm) 1.06 0.97 1.15 1.01 1.12
V, Vanadium (ppm) 16.0 14.6 17.4 15.2 16.9
Y, Yttrium (ppm) 7.01 6.70 7.32 6.79 7.23
Zn, Zinc (ppm) 107 104 110 105 109
SI unit equivalents: ppm (parts per million; 1 x 106) ≡ mg/kg; wt.% (weight per cent) ≡ % (mass fraction).
Note: intervals may appear asymmetric due to rounding.
IND = indeterminate (due to limited reading resolution of the methods employed).

Homogeneity Evaluation
The tolerance limits (ISO 16269:2014) shown in Table 4 were determined using an analysis
of precision errors method and are considered a conservative estimate of true homogeneity.
The meaning of tolerance limits may be illustrated for antimony by peroxide fusion, where

COA-1628-OREAS292-R1 Page: 12 of 23
99% of the time (1-α=0.99) at least 95% of subsamples (ρ=0.95) will have concentrations
lying between 4.47 and 4.62 wt.%. Put more precisely, this means that if the same number
of subsamples were taken and analysed in the same manner repeatedly, 99% of the
tolerance intervals so constructed would cover at least 95% of the total population, and 1%
of the tolerance intervals would cover less than 95% of the total population (ISO Guide 35).
Please note that tolerance limits pertain to the homogeneity of the CRM only and
should not be used as control limits for laboratory performance.

Table 5. Neutron Activation Analysis of Au (in ppm) on 20 x 85mg subsamples and showing the
equivalent results scaled to a 30g sample mass typical of fire assay determination.
Replicate Au Au
No 85mg actual 30g equivalent*
1 11.24 11.276
2 10.82 11.254
3 11.15 11.271
4 11.03 11.265
5 11.36 11.283
6 12.02 11.318
7 10.98 11.262
8 10.86 11.256
9 11.50 11.290
10 11.30 11.279
11 11.33 11.281
12 11.17 11.273
13 11.69 11.300
14 11.70 11.300
15 11.45 11.287
16 11.23 11.276
17 11.28 11.279
18 11.08 11.268
19 11.01 11.264
20 11.37 11.283
Mean 11.278 11.278
Median 11.262 11.277
Std Dev. 0.296 0.016
Rel.Std.Dev. 2.623% 0.140%
�𝑥𝑥 𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼 − 𝑋𝑋�� × 𝑅𝑅𝑅𝑅𝑅𝑅@30𝑔𝑔
*Results calculated for a 30g equivalent sample mass using the formula: 𝑥𝑥 30𝑔𝑔 𝐸𝐸𝐸𝐸 = + 𝑋𝑋�
𝑅𝑅𝑅𝑅𝑅𝑅@85𝑚𝑚𝑚𝑚
where 𝑥𝑥 30𝑔𝑔 𝐸𝐸𝐸𝐸
= equivalent result calculated for a 30g sample mass
(𝑥𝑥 𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼 ) = raw INAA result at 85mg
𝑋𝑋� = mean of 85mg INAA results

The homogeneity of gold has been determined by INAA at ANSTO using the reduced
analytical subsample method which utilises the known relationship between standard
deviation and analytical subsample weight (Ingamells and Switzer, 1973). In this approach
the sample aliquot is substantially reduced to a point where most of the variability in replicate
assays should be due to inhomogeneity of the reference material and measurement error
becomes negligible.

Table 5 above shows the gold INAA data determined on 20 x 85mg subsamples of OREAS 292.
An equivalent scaled version of the results is also provided to demonstrate an appreciation of

COA-1628-OREAS292-R1 Page: 13 of 23
what this data means if 30g fire assays were undertaken without the normal measurement error
associated with this methodology. In this instance, the 1RSD of 0.140% calculated for a 30g fire
assay sample (2.623% at 85mg weights) confirms the high level of gold homogeneity in OREAS
292.

The homogeneity of gold in OREAS 292 has also been evaluated in a nested Analysis of
Variance (ANOVA) of the round robin program. Twenty-one round robin laboratories
received six samples per CRM and these samples were made up of paired samples from
three different, non-adjacent sampling intervals. The purpose of the ANOVA evaluation is to
test that no statistically significant difference exists in the variance between units to that of
the variance within units. This allows an assessment of homogeneity across the entire
prepared batch of OREAS 292. The test was performed using the following parameters:

• Gold fire assay – 114 samples (19 laboratories each providing analyses on 3 pairs of
samples);
• Gold aqua regia digestion – 72 samples (12 laboratories each providing analyses on
3 pairs of samples);
• Null Hypothesis, H0: Between-unit variance is no greater than within-unit variance
(reject H0 if p-value < 0.05);
• Alternative Hypothesis, H1: Between-unit variance is greater than within-unit
variance.

P-values are a measure of probability where values less than 0.05 indicate a greater than
95% probability that the observed differences in within-unit and between-unit variances are
real. The datasets were filtered for both individual and laboratory data set (batch) outliers
prior to the calculation of the p-value.

This process derived p-values of 0.25 for Au by fire assay and 0.94 for Au by aqua regia
digestion. Both p-values are insignificant and the Null Hypothesis is retained. Additionally, none
of the other certified values showed significant p-values. Please note that only results for
constituents present in concentrations well above the detection levels (i.e., >20 x Lower Limit
of Detection) for the various methods undertaken were considered for the objective of
evaluating homogeneity

It is important to note that ANOVA is not an absolute measure of homogeneity. Rather, it

establishes whether or not the analytes are distributed in a similar manner throughout the
packaging run of OREAS 292 and whether the variance between two subsamples from the
same unit is statistically distinguishable from the variance of two subsamples taken from any
two separate units. A reference material therefore can possess poor absolute homogeneity
yet still pass a relative homogeneity (ANOVA) test if the within-unit heterogeneity is large
and similar across all units. Based on the statistical analysis of ANOVA and the results of
the interlaboratory certification program, it can be concluded that OREAS 292 is fit-for-
purpose as a certified reference material (see ‘Intended Use’ below).

COA-1628-OREAS292-R1 Page: 14 of 23
 PREPARER AND SUPPLIER

Certified reference material OREAS 292 was prepared and certified by:

ORE Research & Exploration Pty Ltd Tel: +613-9729 0333

37A Hosie Street Fax: +613-9729 8338
Bayswater North VIC 3153 Web: www.oreas.com
AUSTRALIA Email: info@ore.com.au

PARTICIPATING LABORATORIES

1. Actlabs, Ancaster, Ontario, Canada

2. ALS, Lima, Peru
3. ALS, Loughrea, Galway, Ireland
4. ALS, Perth, WA, Australia
5. ALS, Vancouver, BC, Canada
6. ANSTO, Lucas Heights, NSW, Australia
7. Bureau Veritas Commodities Canada Ltd, Vancouver, BC, Canada
8. Bureau Veritas Geoanalytical, Perth, WA, Australia
9. Bureau Veritas Minerals, Ankara, Central Anatolia, Turkey
10. Gekko Assay Labs, Ballarat, VIC, Australia
11. Inspectorate (BV), Lima, Peru
12. Inspectorate (BV), Manila, Philippines
13. Intertek Genalysis, Perth, WA, Australia
14. Intertek Testing Services, Townsville, QLD, Australia
15. Labwest Minerals Analysis, Perth, WA, Australia
16. On Site Laboratory Services, Bendigo, VIC, Australia
17. PT Geoservices Ltd, Cikarang, Jakarta Raya, Indonesia
18. PT Intertek Utama Services, Jakarta Timur, DKI Jakarta, Indonesia
19. SGS Canada Inc., Vancouver, BC, Canada
20. SGS de Mexico SA de CV, Cd. Industrial, Durango, Mexico
21. SGS del Peru, Lima, Peru
22. SGS Geosol Laboratorios Ltda, Vespasiano, Minas Gerais, Brazil

Please note: To preserve anonymity, the above numbered alphabetical list of

participating laboratories does not correspond with the Lab ID numbering on the
scatter plots below.

COA-1628-OREAS292-R1 Page: 15 of 23
 Figure 1. Au by Fire Assay in OREAS 292

COA-1628-OREAS292-R1 Page: 16 of 23
 Figure 2. Au by aqua regia digestion in OREAS 292

COA-1628-OREAS292-R1 Page: 17 of 23
 Figure 3. Sb by peroxide fusion with ICP finish in OREAS 292

COA-1628-OREAS292-R1 Page: 18 of 23
 METROLOGICAL TRACEABILITY

The analytical samples were selected in a manner to represent the entire batch of prepared
CRM. This ‘representivity’ was maintained in each submitted laboratory sample batch and
ensures the user that the data is traceable from sample selection through to the analytical
results that underlie the consensus values. Each analytical data set has been validated by
its assayer through the inclusion of internal reference materials and QC checks during
analysis.

The laboratories were chosen on the basis of their competence (from past performance in
inter-laboratory programs undertaken by ORE Pty Ltd) for a particular analytical method,
analyte or analyte suite, and sample matrix. Most of these laboratories have and maintain
ISO 17025 accreditation. The certified values presented in this report are calculated from
the means of accepted data following robust statistical treatment as detailed in this report.

Guide ISO/TR 16476:2016, section 5.3.1 describes metrological traceability in reference

materials as it pertains to the transformation of the measurand. In this section it states,
“Although the determination of the property value itself can be made traceable to appropriate
units through, for example, calibration of the measurement equipment used, steps like the
transformation of the sample from one physical (chemical) state to another cannot. Such
transformations may only be compared with a reference (when available), or among
themselves. For some transformations, reference methods have been defined and may be
used in certification projects to evaluate the uncertainty associated with such a
transformation. In other cases, only a comparison among different laboratories using
the same procedure is possible. In this case, it is impossible to demonstrate absence
of method bias; therefore, the result is an operationally defined measurand (ISO Guide
35:2017, 9.2.4c).” Certification takes place on the basis of agreement among operationally
defined, independent measurement results.

COMMUTABILITY

The measurements of the results that underlie the certified values contained in this report
were undertaken by methods involving pre-treatment (digestion/fusion) of the sample. This
served to reduce the sample to a simple and well understood form permitting calibration
using simple solutions of the CRM. Due to these methods being well understood and highly
effective, commutability is not an issue for this CRM. Being matrix-matched, OREAS 292
will display similar behaviour in the relevant measurement process to the routine ‘process’
samples for which OREAS 292 is designated to monitor. To maintain commutability, care
should be taken to always ensure ‘matrix matching’ as close as practically achievable. The
matrix of the CRM is described in the ‘Source Material’ section and users should select
appropriate CRMs matching these attributes to their field samples.

INTENDED USE

OREAS 292 is intended to cover all activities needed to produce a measurement result. This
includes extraction, possible separation steps and the actual measurement process (the
signal producing step). OREAS 292 may be used to calibrate the entire procedure by
producing a pure substance CRM transformed into a calibration solution. OREAS 292 is
intended for the following uses:

COA-1628-OREAS292-R1 Page: 19 of 23
 • For the monitoring of laboratory performance in the analysis of analytes reported in
Table 1 in geological samples;
• For the verification of analytical methods for analytes reported in Table 1;
• For the calibration of instruments used in the determination of the concentration of
analytes reported in Table 1.

MINIMUM SAMPLE SIZE

To relate analytical determinations to the values in this certificate, the minimum mass of
sample used should match the typical mass that the laboratories used in the interlaboratory
(round robin) certification program. This means that different minimum sample masses
should be used depending on the operationally defined methodology as follows:
• Au by fire assay: ≥10g;
• Au by aqua regia digestion ICP finish: ≥1g.;
• Peroxide fusion with ICP finish: ≥0.1g;
• 4-acid digestion with ICP-OES and/or MS finish: ≥0.25g;
• Aqua regia digestion with ICP-OES and/or MS finish: ≥0.5g.

PERIOD OF VALIDITY & STORAGE INSTRUCTIONS

The certification of OREAS 292 remains valid, within the specified measurement
uncertainties, until August 2037, provided the CRM is handled and stored in accordance
with the instructions given below. This certification is nullified if the CRM is any way changed
or contaminated.

Store in a clean and cool dry place away from direct sunlight.

Long-term stability will be monitored at appropriate intervals and purchasers notified if any
changes are observed. The period of validity may well be indefinite and will be reassessed
prior to expiry with the aim of extending the validity if possible.

Single-use sachets
OREAS 292 contains a significant concentration of Sulphur (2.1 wt.% S) and is packaged
under dry nitrogen in single-use, laminated foil sachets. Following analysis, it is the
manufacturer’s expectation that any remaining material is discarded. It is the user’s
responsibility to prevent contamination and avoid prolonged exposure of the sample to the
atmosphere prior to analysis.

OREAS 292 contains a non-hygroscopic* matrix with an indicative value for moisture
provided to enable users to check for changes to stored material by determining moisture in
the user’s laboratory and comparing the result to the value in Table 3 in this certificate.

*A non-hygroscopic matrix means exposure to atmospheres significantly different, in terms of temperature and humidity,
from the climate during manufacturing should have negligible impact on the precision of results. Hygroscopic moisture is
the amount of adsorped moisture (weakly held H2O- molecules on the surface of exposed material) following exposure to
the local atmosphere. Usually, equilibration of material to the local atmosphere will only occur if the material is spread into
a thin (~2mm thick) layer and left exposed for a period of 2 hours.

COA-1628-OREAS292-R1 Page: 20 of 23
 INSTRUCTIONS FOR HANDLING & CORRECT USE

Pre-homogenisation of the CRM prior to subsampling and analysis is not necessary as there
is no particle segregation under transport [12].

Fine powders pose a risk to eyes and lungs and therefore standard precautions including
the use of safety glasses and dust masks are advised.

QC monitoring using multiples of the Standard Deviation (SD)

In the application of SD’s in monitoring performance it is important to note that not all
laboratories function at the same level of proficiency and that different methods in use at a
particular laboratory have differing levels of precision. Each laboratory has its own inherent
SD (for a specific concentration level and analyte-method pair) based on the analytical
process and this SD is not directly related to the round robin program.

The majority of data generated in the round robin program was produced by a selection of
world class laboratories. The SD’s thus generated are more constrained than those that
would be produced across a randomly selected group of laboratories. To produce more
generally achievable SD’s the ‘pooled’ SD’s provided in this report include interlaboratory
bias. This ‘one size fits all’ approach may require revision at the discretion of the QC
manager concerned following careful scrutiny of QC control charts.

The performance gates shown in Table 1 are intended only to be used as a first principle
guide as to what a laboratory may be able to achieve. Over a period of time monitoring your
own laboratory’s data for this CRM, SD's should be calculated directly from your own
laboratory's process. This will enable you to establish more specific performance gates that
are fit for purpose for your application as well as the ability to monitor bias. If your long-term
trend analysis shows an average value that is within the 95% confidence interval then
generally there is no cause for concern in regard to bias.

For use with the aqua regia digestion method

It is important to note that in the analytical industry there is no standardisation of the aqua
regia digestion process. This method is a partial empirical digest and differences in
recoveries for various analytes are commonplace. These are caused by variations in the
digest conditions and can include the ratio of nitric to hydrochloric acids, acid strength,
temperatures, leach times and secondary digestions. Recoveries for sulphide-hosted base
metal sulphides approach total values, however, other analytes, in particular the lithophile
elements, show greater sensitivity to method parameters. This can result in lack of
consensus in an inter-laboratory certification program for these elements.

The approach applied here is to report certified values in those instances where reasonable
agreement exists amongst a majority of participating laboratories. The results of specific
laboratories may differ significantly from the certified values, but will, nonetheless, be valid
and reproducible in the context of the specifics of the aqua regia method in use. Users of
this reference material should, therefore, be mindful of this limitation when applying the
certified values in a quality control program.

LEGAL NOTICE

Ore Research & Exploration Pty Ltd has prepared and statistically evaluated the property
values of this reference material to the best of its ability. The Purchaser by receipt hereof

COA-1628-OREAS292-R1 Page: 21 of 23
releases and indemnifies Ore Research & Exploration Pty Ltd from and against all liability
and costs arising from the use of this material and information.

DOCUMENT HISTORY

Revision
Date Changes applied
No.

Minor revision has been made to the certified values and associated
statistics for multi-element aqua regia and 4-acid digestion (one
1 19th September, 2022
laboratory’s aqua regia results were inadvertently mapped as 4-acid
digestion and vice versa).

0 9th August, 2022 First publication.

QMS ACCREDITATION
ORE Pty Ltd is accredited to ISO 9001:2015 by Lloyd’s Register Quality Assurance Ltd for
its quality management system including development, manufacturing, certification and
supply of CRMs.

CERTIFYING OFFICER

19th September, 2022

Craig Hamlyn (B.Sc. Hons - Geology), Technical Manager - ORE P/L

REFERENCES

[1] Govett, G.J.S. (1983). Handbook of Exploration Geochemistry, Volume 2: Statistics and
Data Analysis in Geochemical Prospecting (Variations of accuracy and precision).
[2] Ingamells, C. O. and Switzer, P. (1973). A Proposed Sampling Constant for Use in
Geochemical Analysis, Talanta 20, 547-568.
[3] ISO Guide 30:2015. Terms and definitions used in connection with reference materials.
[4] ISO Guide 31:2015. Reference materials – Contents of certificates and labels.
[5] ISO Guide 35:2017. Certification of reference materials - General and statistical
principals.
[6] JCGM 100:2008; Evaluation of Measurement Data — Guide to the Expression of
Uncertainty in Measurement (GUM 1995 with Minor Corrections); Joint Committee
for Guides in Metrology (JCGM) (2008); available at
www.bipm.org/utils/common/documents/jcgm/JCGM_100_2008_E.pdf (accessed

COA-1628-OREAS292-R1 Page: 22 of 23
 Nov 2021), (also known as ISO Guide 98-3:2008. Guide to the expression of
uncertainty in measurement).
[7] ISO 16269:2014. Statistical interpretation of data – Part 6: Determination of statistical
tolerance intervals.
[8] ISO/TR 16476:2016, Reference Materials – Establishing and expressing metrological
traceability of quantity values assigned to reference materials.
[9] ISO 17025:2005, General requirements for the competence of testing and calibration
laboratories.
[10] ISO Guide 17034:2016. General requirements for the competence of reference
material producers.
[11] OREAS-BUP-70-09-11: Statistical Analysis - OREAS Evaluation Method.
[12] OREAS-TN-04-1498: Stability under transport; an experimental study of OREAS
CRMs.
[13] OREAS-TN-05-1674: Long-term storage stability; an experimental study of OREAS
CRMs.
[14] Thompson, A.; Taylor, B.N.; Guide for the Use of the International System of Units
(SI); NIST Special Publication 811; U.S. Government Printing Office: Washington,
DC (2008); available at: https://physics.nist.gov/cuu/pdf/sp811.pdf (accessed Nov
2021).
[15] Van der Veen AMH and Pauwels, J. (2001), Accred Qual Assur 6: 290-294.

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