OREAS 281
SKU: 281
OREAS 281 was prepared from a blend of high-grade gold ore and barren
materials comprising quartz, black slate, pyrite, white marble, dolomite, and
graphite. The ore was sourced from the Leeville Mine, near the western crest of
the Tuscarora Mountains, approximately 20 miles northwest of Carlin, Nevada,
USA. Leeville is an underground, high-grade refractory gold deposit on the
Carlin Trend. The ore was provided by Nevada Gold Mines, operated under
Barrick’s management. The Leeville deposit is hosted in carbonate rocks within
the Carlin Trend, where gold occurs as fine-grained, disseminated, and
structurally controlled Carlin-type mineralisation, commonly associated with
pyrite and arsenian pyrite in decalcified and weakly to moderately silicified
zones.
The ore is double-refractory, containing both sulphidic sulphur and
carbonaceous (organic) matter. Gold occurs as submicroscopic inclusions within
sulphide minerals and is also adsorbed onto organic carbon surfaces, which can
exhibit strong preg-robbing behaviour during cyanidation.
Fifty-nine commercial analytical laboratories participated in the program to
certify the elements reported below using the following methods:
Gold by Pb collection fire assay (25-50g charge weight) with AAS and
ICP-OES finish
Gold by Bi collection fire assay (30 g charge weight) with AAS finish
Gold by PhotonAssay™ (protocol PAAU02) with recommended gross fill mass of
450-480 g
Total C and S by IR combustion furnace
Full ICP-OES and ICP-MS elemental suites by 4-acid (HNO3-HF-HClO4-HCl)
digestion
Full ICP-OES and ICP-MS elemental suites by aqua regia digestion
To confirm homogeneity, gold by instrumental neutron activation analysis
(INAA) was undertaken on 20 x 85mg. This format enabled a nested ANOVA treatment
of the INAA results to compare within- and between-unit variances, providing a
statistical measure of batch homogeneity.
Specifications
- State: primary
- Matrix: siliceous shale
- Mineralisation: Carlin style
- CRM Group: Au >1 ppm, Au only
Certified Values
| Analyte | Certified Value | 1SD | 95% CL Low | 95% CL High | Method |
|---|---|---|---|---|---|
| Au, Gold (ppm) | 10.90 | 0.404 | 10.78 | 11.02 | Pb Fire Assay |
| Au, Gold (ppm) | 10.90 | 0.346 | Bi Fire Assay | ||
| Au, Gold (ppm) | 11.18 | 0.180 | 11.13 | 11.24 | PhotonAssay |
| C, Carbon (wt.%) | 0.937 | 0.028 | 0.916 | 0.958 | Infrared Combustion |
| S, Sulphur (wt.%) | 1.63 | 0.042 | 1.60 | 1.67 | Infrared Combustion |
| Ag, Silver (ppm) | 0.479 | 0.041 | 0.446 | 0.513 | 4-Acid Digestion |
| Al, Aluminium (wt.%) | 2.86 | 0.081 | 2.78 | 2.94 | 4-Acid Digestion |
| As, Arsenic (wt.%) | 0.150 | 0.004 | 0.145 | 0.155 | 4-Acid Digestion |
| Ba, Barium (ppm) | 1026 | 166 | 944 | 1109 | 4-Acid Digestion |
| Be, Beryllium (ppm) | 0.47 | 0.041 | 0.42 | 0.53 | 4-Acid Digestion |
| Bi, Bismuth (ppm) | 0.58 | 0.037 | 0.55 | 0.62 | 4-Acid Digestion |
| Ca, Calcium (wt.%) | 1.60 | 0.065 | 1.54 | 1.65 | 4-Acid Digestion |
| Cd, Cadmium (ppm) | 0.25 | 0.03 | 0.22 | 0.29 | 4-Acid Digestion |
| Ce, Cerium (ppm) | 28.1 | 1.40 | 26.9 | 29.4 | 4-Acid Digestion |
| Co, Cobalt (ppm) | 10.0 | 0.68 | 9.5 | 10.5 | 4-Acid Digestion |
| Cr, Chromium (ppm) | 201 | 53 | 173 | 229 | 4-Acid Digestion |
| Cs, Caesium (ppm) | 2.17 | 0.085 | 2.08 | 2.25 | 4-Acid Digestion |
| Cu, Copper (ppm) | 227 | 7 | 220 | 234 | 4-Acid Digestion |
| Dy, Dysprosium (ppm) | 2.36 | 0.26 | 2.10 | 2.61 | 4-Acid Digestion |
| Er, Erbium (ppm) | 1.35 | 0.20 | 1.15 | 1.55 | 4-Acid Digestion |
| Eu, Europium (ppm) | 0.65 | 0.12 | 0.54 | 0.77 | 4-Acid Digestion |
| Fe, Iron (wt.%) | 1.87 | 0.058 | 1.82 | 1.93 | 4-Acid Digestion |
| Ga, Gallium (ppm) | 6.96 | 0.339 | 6.59 | 7.32 | 4-Acid Digestion |
| Gd, Gadolinium (ppm) | 2.89 | 0.164 | 2.65 | 3.12 | 4-Acid Digestion |
| Hf, Hafnium (ppm) | 1.34 | 0.106 | 1.22 | 1.47 | 4-Acid Digestion |
| Ho, Holmium (ppm) | 0.45 | 0.05 | 0.39 | 0.52 | 4-Acid Digestion |
| In, Indium (ppm) | 0.044 | 0.008 | 0.036 | 0.051 | 4-Acid Digestion |
| K, Potassium (wt.%) | 0.420 | 0.017 | 0.407 | 0.432 | 4-Acid Digestion |
| La, Lanthanum (ppm) | 15.5 | 0.48 | 14.8 | 16.3 | 4-Acid Digestion |
| Li, Lithium (ppm) | 28.8 | 1.36 | 27.4 | 30.3 | 4-Acid Digestion |
| Lu, Lutetium (ppm) | 0.18 | 0.016 | 0.15 | 0.21 | 4-Acid Digestion |
| Mg, Magnesium (wt.%) | 0.279 | 0.013 | 0.267 | 0.290 | 4-Acid Digestion |
| Mn, Manganese (wt.%) | 0.006 | 0.000 | 0.005 | 0.006 | 4-Acid Digestion |
| Mo, Molybdenum (ppm) | 17.8 | 0.69 | 17.0 | 18.7 | 4-Acid Digestion |
| Na, Sodium (wt.%) | 0.019 | 0.005 | 0.018 | 0.021 | 4-Acid Digestion |
| Nb, Niobium (ppm) | 6.81 | 0.519 | 6.40 | 7.22 | 4-Acid Digestion |
| Nd, Neodymium (ppm) | 15.2 | 0.56 | 13.9 | 16.4 | 4-Acid Digestion |
| Ni, Nickel (ppm) | 72 | 3.6 | 69 | 74 | 4-Acid Digestion |
| P, Phosphorus (wt.%) | 0.159 | 0.006 | 0.154 | 0.163 | 4-Acid Digestion |
| Pb, Lead (ppm) | 7.60 | 0.558 | 7.15 | 8.06 | 4-Acid Digestion |
| Pr, Praseodymium (ppm) | 3.83 | 0.130 | 3.52 | 4.13 | 4-Acid Digestion |
| Rb, Rubidium (ppm) | 24.3 | 1.16 | 23.3 | 25.3 | 4-Acid Digestion |
| Re, Rhenium (ppm) | 0.024 | 0.002 | 0.021 | 0.028 | 4-Acid Digestion |
| S, Sulphur (wt.%) | 1.61 | 0.043 | 1.56 | 1.67 | 4-Acid Digestion |
| Sb, Antimony (ppm) | 251 | 13 | 241 | 260 | 4-Acid Digestion |
| Sc, Scandium (ppm) | 2.73 | 0.157 | 2.57 | 2.88 | 4-Acid Digestion |
| Se, Selenium (ppm) | 1.84 | 0.48 | 1.15 | 2.53 | 4-Acid Digestion |
| Sm, Samarium (ppm) | 2.99 | 0.153 | 2.67 | 3.32 | 4-Acid Digestion |
| Sn, Tin (ppm) | 1.55 | 0.108 | 1.41 | 1.69 | 4-Acid Digestion |
| Sr, Strontium (ppm) | 21.7 | 0.73 | 20.8 | 22.5 | 4-Acid Digestion |
| Ta, Tantalum (ppm) | 0.41 | 0.06 | 0.37 | 0.45 | 4-Acid Digestion |
| Tb, Terbium (ppm) | 0.39 | 0.018 | 0.36 | 0.42 | 4-Acid Digestion |
| Te, Tellurium (ppm) | 0.63 | 0.057 | 0.55 | 0.70 | 4-Acid Digestion |
| Th, Thorium (ppm) | 4.93 | 0.286 | 4.60 | 5.26 | 4-Acid Digestion |
| Ti, Titanium (wt.%) | 0.155 | 0.006 | 0.150 | 0.161 | 4-Acid Digestion |
| Tl, Thallium (ppm) | 18.6 | 1.02 | 17.8 | 19.4 | 4-Acid Digestion |
| Tm, Thulium (ppm) | 0.17 | 0.016 | 0.14 | 0.20 | 4-Acid Digestion |
| U, Uranium (ppm) | 6.02 | 0.338 | 5.70 | 6.35 | 4-Acid Digestion |
| V, Vanadium (ppm) | 184 | 7 | 178 | 189 | 4-Acid Digestion |
| W, Tungsten (ppm) | 52 | 4.0 | 48 | 55 | 4-Acid Digestion |
| Y, Yttrium (ppm) | 15.9 | 1.05 | 14.9 | 16.8 | 4-Acid Digestion |
| Yb, Ytterbium (ppm) | 1.18 | 0.094 | 1.03 | 1.33 | 4-Acid Digestion |
| Zn, Zinc (ppm) | 41.2 | 2.60 | 39.3 | 43.0 | 4-Acid Digestion |
| Zr, Zirconium (ppm) | 48.1 | 2.30 | 45.4 | 50.9 | 4-Acid Digestion |
| Ag, Silver (ppm) | 0.460 | 0.039 | 0.424 | 0.496 | Aqua Regia Digestion |
| Al, Aluminium (wt.%) | 0.684 | 0.060 | 0.640 | 0.727 | Aqua Regia Digestion |
| As, Arsenic (wt.%) | 0.151 | 0.006 | 0.146 | 0.157 | Aqua Regia Digestion |
| Au, Gold (ppm) | 7.13 | 0.493 | 6.52 | 7.74 | Aqua Regia Digestion |
| B, Boron (ppm) | < 10.0 | IND | IND | IND | Aqua Regia Digestion |
| Be, Beryllium (ppm) | 0.13 | 0.02 | 0.10 | 0.15 | Aqua Regia Digestion |
| Bi, Bismuth (ppm) | 0.56 | 0.035 | 0.53 | 0.60 | Aqua Regia Digestion |
| Ca, Calcium (wt.%) | 1.55 | 0.075 | 1.49 | 1.60 | Aqua Regia Digestion |
| Cd, Cadmium (ppm) | 0.24 | 0.021 | 0.21 | 0.27 | Aqua Regia Digestion |
| Ce, Cerium (ppm) | 22.9 | 0.99 | 22.0 | 23.9 | Aqua Regia Digestion |
| Co, Cobalt (ppm) | 9.63 | 0.498 | 9.26 | 10.00 | Aqua Regia Digestion |
| Cr, Chromium (ppm) | 36.7 | 2.69 | 34.3 | 39.0 | Aqua Regia Digestion |
| Cs, Caesium (ppm) | 0.94 | 0.073 | 0.88 | 1.01 | Aqua Regia Digestion |
| Cu, Copper (ppm) | 227 | 7 | 220 | 234 | Aqua Regia Digestion |
| Fe, Iron (wt.%) | 1.81 | 0.073 | 1.75 | 1.87 | Aqua Regia Digestion |
| Ga, Gallium (ppm) | 2.17 | 0.26 | 1.97 | 2.37 | Aqua Regia Digestion |
| Hf, Hafnium (ppm) | 0.18 | 0.02 | 0.16 | 0.20 | Aqua Regia Digestion |
| Hg, Mercury (ppm) | 8.11 | 0.475 | 7.66 | 8.55 | Aqua Regia Digestion |
| In, Indium (ppm) | 0.036 | 0.004 | 0.030 | 0.043 | Aqua Regia Digestion |
| K, Potassium (wt.%) | 0.106 | 0.012 | 0.096 | 0.115 | Aqua Regia Digestion |
| La, Lanthanum (ppm) | 12.3 | 0.59 | 11.8 | 12.8 | Aqua Regia Digestion |
| Li, Lithium (ppm) | 4.41 | 0.56 | 4.04 | 4.77 | Aqua Regia Digestion |
| Mg, Magnesium (wt.%) | 0.211 | 0.011 | 0.199 | 0.222 | Aqua Regia Digestion |
| Mn, Manganese (wt.%) | 0.005 | 0.000 | 0.005 | 0.005 | Aqua Regia Digestion |
| Mo, Molybdenum (ppm) | 17.4 | 0.88 | 16.7 | 18.2 | Aqua Regia Digestion |
| Ni, Nickel (ppm) | 69 | 3.5 | 66 | 72 | Aqua Regia Digestion |
| P, Phosphorus (wt.%) | 0.159 | 0.007 | 0.153 | 0.165 | Aqua Regia Digestion |
| Pb, Lead (ppm) | 6.84 | 0.659 | 6.44 | 7.24 | Aqua Regia Digestion |
| Rb, Rubidium (ppm) | 6.31 | 0.70 | 5.86 | 6.76 | Aqua Regia Digestion |
| Re, Rhenium (ppm) | 0.024 | 0.002 | 0.021 | 0.026 | Aqua Regia Digestion |
| S, Sulphur (wt.%) | 1.59 | 0.037 | 1.55 | 1.63 | Aqua Regia Digestion |
| Sb, Antimony (ppm) | 216 | 17 | 204 | 228 | Aqua Regia Digestion |
| Sc, Scandium (ppm) | 0.98 | 0.13 | 0.88 | 1.08 | Aqua Regia Digestion |
| Se, Selenium (ppm) | 1.56 | 0.22 | 1.31 | 1.82 | Aqua Regia Digestion |
| Sn, Tin (ppm) | 1.01 | 0.085 | 0.92 | 1.09 | Aqua Regia Digestion |
| Sr, Strontium (ppm) | 13.4 | 0.94 | 12.7 | 14.1 | Aqua Regia Digestion |
| Ta, Tantalum (ppm) | < 0.010 | IND | IND | IND | Aqua Regia Digestion |
| Tb, Terbium (ppm) | 0.33 | 0.009 | 0.31 | 0.35 | Aqua Regia Digestion |
| Te, Tellurium (ppm) | 0.57 | 0.06 | 0.50 | 0.65 | Aqua Regia Digestion |
| Th, Thorium (ppm) | 3.85 | 0.242 | 3.69 | 4.01 | Aqua Regia Digestion |
| Ti, Titanium (wt.%) | 0.005 | 0.001 | 0.004 | 0.006 | Aqua Regia Digestion |
| Tl, Thallium (ppm) | 17.7 | 1.10 | 16.9 | 18.6 | Aqua Regia Digestion |
| U, Uranium (ppm) | 4.41 | 0.377 | 4.19 | 4.64 | Aqua Regia Digestion |
| V, Vanadium (ppm) | 66 | 5.4 | 62 | 70 | Aqua Regia Digestion |
| W, Tungsten (ppm) | 17.5 | 1.9 | 16.4 | 18.7 | Aqua Regia Digestion |
| Y, Yttrium (ppm) | 9.30 | 0.508 | 8.87 | 9.73 | Aqua Regia Digestion |
| Yb, Ytterbium (ppm) | 0.50 | 0.013 | 0.46 | 0.53 | Aqua Regia Digestion |
| Zn, Zinc (ppm) | 39.4 | 1.44 | 37.7 | 41.1 | Aqua Regia Digestion |
| Zr, Zirconium (ppm) | 6.13 | 0.68 | 5.68 | 6.57 | Aqua Regia Digestion |
Product Specifications
Certified Reference Values
| Analyte | Certified Value | Uncertainty (1SD) | 95% Confidence Low | 95% Confidence High | Method |
|---|---|---|---|---|---|
| Ce - Cerium (ppm) | 28.1 | - | - | - | 4-Acid Digestion |
| Dy - Dysprosium (ppm) | 2.36 | - | - | - | 4-Acid Digestion |
| Er - Erbium (ppm) | 1.35 | - | - | - | 4-Acid Digestion |
| Eu - Europium (ppm) | 0.65 | - | - | - | 4-Acid Digestion |
| Gd - Gadolinium (ppm) | 2.89 | - | - | - | 4-Acid Digestion |
| Ho - Holmium (ppm) | 0.45 | - | - | - | 4-Acid Digestion |
| La - Lanthanum (ppm) | 15.5 | - | - | - | 4-Acid Digestion |
| Lu - Lutetium (ppm) | 0.18 | - | - | - | 4-Acid Digestion |
| Nd - Neodymium (ppm) | 15.2 | - | - | - | 4-Acid Digestion |
| Pr - Praseodymium (ppm) | 3.83 | - | - | - | 4-Acid Digestion |
| Sm - Samarium (ppm) | 2.99 | - | - | - | 4-Acid Digestion |
| Tb - Terbium (ppm) | 0.39 | - | - | - | 4-Acid Digestion |
| Tm - Thulium (ppm) | 0.17 | - | - | - | 4-Acid Digestion |
| Y - Yttrium (ppm) | 15.9 | - | - | - | 4-Acid Digestion |
| Yb - Ytterbium (ppm) | 1.18 | - | - | - | 4-Acid Digestion |
| Ag - Silver (ppm) | 0.460 | - | - | - | Aqua Regia |
| Bi - Bismuth (ppm) | 0.56 | - | - | - | Aqua Regia |
| Cd - Cadmium (ppm) | 0.24 | - | - | - | Aqua Regia |
| Co - Cobalt (ppm) | 9.63 | - | - | - | Aqua Regia |
| Cu - Copper (ppm) | 227 | - | - | - | Aqua Regia |
| Hg - Mercury (ppm) | 8.11 | - | - | - | Aqua Regia |
| Ni - Nickel (ppm) | 69 | - | - | - | Aqua Regia |
| Pb - Lead (ppm) | 6.84 | - | - | - | Aqua Regia |
| Sb - Antimony (ppm) | 216 | - | - | - | Aqua Regia |
| Se - Selenium (ppm) | 1.56 | - | - | - | Aqua Regia |
| Sn - Tin (ppm) | 1.01 | - | - | - | Aqua Regia |
| Te - Tellurium (ppm) | 0.57 | - | - | - | Aqua Regia |
| Zn - Zinc (ppm) | 39.4 | - | - | - | Aqua Regia |
SD = Standard Deviation | CL = 95% Confidence Limits
Methods: AR = Aqua Regia, 4-Acid = 4-Acid Digestion, LBF = Lithium Borate Fusion, FA/AAS = Fire Assay with Atomic Absorption, LECO = LECO Combustion Analysis
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