OREAS 251b

OREAS 251b was prepared from a blend of gold-bearing oxide ore and barren materials (basaltic scoria, quartz and mudstone). The ore (Wilber Lode) was sourced from the Andy Well Gold Project located approximately 45km north of Meekatharra in the Murchison region of Western Australia. The Wilber Lode is a shear- hosted, narrow vein, quartz lode-style gold deposit situated within the Meekatharra-Wydgee greenstone belt in the Archaean Yilgarn Craton of Western Australia. The common primary mineral assemblage as stated by Mason and Harris (2011, 2012, cited in Hingston et al, 2014) is quartz, calcite, chlorite, fuchsite, pyrite, galena, sphalerite, chalcopyrite and gold. The host rock consists of a complex sequence of weathered Archaean meta-basalt and meta-porphyritic rocks derived from a primary mineralogy of albite, actinolite, chlorite, sericite, biotite, calcite, zoisite, muscovite, quartz and titanate. Thirty-one commercial analytical laboratories participated in the program to certify the elements reported below.

  • Gold by fire assay (25-50g charge weight) with AAS and ICP-OES finish;
  • Gold by aqua regia digestion (15-50g sample weight) with ICP-OES and/or ICP-MS finish;
  • Gold by cyanide leach (20-200g) with AAS or ICP-MS finish;
  • Gold by x-ray photon assay on ~350g sample weights (12 Chrysos PhotonAssay units at 7 laboratories with two rounds of data reported from each unit);
  • Full ICP-OES and ICP-MS elemental suites by 4-acid 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 1g subsamples (see Table 5 in the ‘Homogeneity Evaluation’ of the Certificate).

Analyte Certified Value 1SD Expanded Uncertainty Low Expanded Uncertainty High Method
Au, Gold (ppm) 0.505 0.017 0.497 0.513 Pb Fire Assay
Au, Gold (ppm) 0.497 0.022 0.487 0.507 Aqua Regia Digestion (sample weights 10-50g)
Au, Gold (ppm) 0.491 0.028 0.477 0.505 Cyanide Leach
Au, Gold (ppm) 0.499 0.033 0.486 0.512 PhotonAssay
Ag, Silver (ppm) 0.123 0.017 0.104 0.141 4-Acid Digestion
Al, Aluminium (wt.%) 4.80 0.114 4.70 4.90 4-Acid Digestion
As, Arsenic (ppm) 12.9 0.56 12.3 13.5 4-Acid Digestion
Ba, Barium (ppm) 311 14 300 322 4-Acid Digestion
Be, Beryllium (ppm) 1.25 0.079 1.17 1.34 4-Acid Digestion
Bi, Bismuth (ppm) 0.31 0.026 0.27 0.35 4-Acid Digestion
Ca, Calcium (wt.%) 2.01 0.073 1.96 2.06 4-Acid Digestion
Cd, Cadmium (ppm) 0.027 0.008 0.018 0.036 4-Acid Digestion
Ce, Cerium (ppm) 51 4.8 48 54 4-Acid Digestion
Co, Cobalt (ppm) 18.0 0.73 17.2 18.8 4-Acid Digestion
Cr, Chromium (ppm) 115 11 108 122 4-Acid Digestion
Cs, Caesium (ppm) 2.80 0.161 2.68 2.92 4-Acid Digestion
Cu, Copper (ppm) 26.7 2.35 24.9 28.5 4-Acid Digestion
Dy, Dysprosium (ppm) 3.14 0.286 2.87 3.40 4-Acid Digestion
Er, Erbium (ppm) 1.54 0.18 1.38 1.69 4-Acid Digestion
Eu, Europium (ppm) 1.10 0.055 1.04 1.16 4-Acid Digestion
Fe, Iron (wt.%) 3.69 0.098 3.60 3.78 4-Acid Digestion
Ga, Gallium (ppm) 12.6 1.03 11.9 13.2 4-Acid Digestion
Gd, Gadolinium (ppm) 4.03 0.210 3.75 4.32 4-Acid Digestion
Ge, Germanium (ppm) 0.11 0.02 0.07 0.15 4-Acid Digestion
Hf, Hafnium (ppm) 2.94 0.266 2.72 3.16 4-Acid Digestion
Ho, Holmium (ppm) 0.57 0.050 0.51 0.62 4-Acid Digestion
In, Indium (ppm) 0.065 0.005 0.058 0.072 4-Acid Digestion
K, Potassium (wt.%) 1.17 0.036 1.14 1.20 4-Acid Digestion
La, Lanthanum (ppm) 25.8 1.79 24.6 27.1 4-Acid Digestion
Li, Lithium (ppm) 21.0 1.66 20.0 22.0 4-Acid Digestion
Lu, Lutetium (ppm) 0.20 0.014 0.19 0.22 4-Acid Digestion
Mg, Magnesium (wt.%) 1.67 0.063 1.62 1.71 4-Acid Digestion
Mn, Manganese (wt.%) 0.042 0.001 0.041 0.044 4-Acid Digestion
Mo, Molybdenum (ppm) 1.84 0.106 1.71 1.98 4-Acid Digestion
Na, Sodium (wt.%) 0.774 0.024 0.754 0.794 4-Acid Digestion
Nb, Niobium (ppm) 14.4 1.5 13.5 15.3 4-Acid Digestion
Nd, Neodymium (ppm) 23.7 0.85 22.5 25.0 4-Acid Digestion
Ni, Nickel (ppm) 72 3.5 70 75 4-Acid Digestion
P, Phosphorus (wt.%) 0.070 0.001 0.068 0.072 4-Acid Digestion
Pb, Lead (ppm) 9.06 0.718 8.46 9.66 4-Acid Digestion
Pr, Praseodymium (ppm) 6.21 0.245 5.87 6.55 4-Acid Digestion
Rb, Rubidium (ppm) 63 2.6 61 65 4-Acid Digestion
Re, Rhenium (ppm) < 0.002 IND IND IND 4-Acid Digestion
S, Sulphur (wt.%) 0.017 0.004 0.015 0.019 4-Acid Digestion
Sb, Antimony (ppm) 0.79 0.071 0.73 0.84 4-Acid Digestion
Sc, Scandium (ppm) 9.68 0.574 9.23 10.12 4-Acid Digestion
Se, Selenium (ppm) < 1.00 IND IND IND 4-Acid Digestion
Sm, Samarium (ppm) 4.72 0.221 4.38 5.06 4-Acid Digestion
Sn, Tin (ppm) 3.65 0.327 3.41 3.89 4-Acid Digestion
Sr, Strontium (ppm) 196 8 190 201 4-Acid Digestion
Ta, Tantalum (ppm) 1.03 0.082 0.96 1.11 4-Acid Digestion
Tb, Terbium (ppm) 0.58 0.038 0.54 0.62 4-Acid Digestion
Te, Tellurium (ppm) < 0.050 IND IND IND 4-Acid Digestion
Th, Thorium (ppm) 8.65 0.589 8.26 9.05 4-Acid Digestion
Ti, Titanium (wt.%) 0.481 0.020 0.466 0.496 4-Acid Digestion
Tl, Thallium (ppm) 0.35 0.021 0.33 0.37 4-Acid Digestion
Tm, Thulium (ppm) 0.21 0.02 0.19 0.24 4-Acid Digestion
U, Uranium (ppm) 1.27 0.079 1.19 1.35 4-Acid Digestion
V, Vanadium (ppm) 75 3.5 72 77 4-Acid Digestion
W, Tungsten (ppm) 1.97 0.22 1.81 2.14 4-Acid Digestion
Y, Yttrium (ppm) 15.2 1.13 14.5 15.9 4-Acid Digestion
Yb, Ytterbium (ppm) 1.39 0.16 1.25 1.54 4-Acid Digestion
Zn, Zinc (ppm) 60 3.1 58 62 4-Acid Digestion
Zr, Zirconium (ppm) 108 9 102 113 4-Acid Digestion
Ag, Silver (ppm) 0.104 0.010 0.094 0.114 Aqua Regia Digestion
Al, Aluminium (wt.%) 0.871 0.126 0.807 0.935 Aqua Regia Digestion
As, Arsenic (ppm) 6.01 0.62 5.61 6.42 Aqua Regia Digestion
B, Boron (ppm) < 10.0 IND IND IND Aqua Regia Digestion
Ba, Barium (ppm) 67 3.7 64 69 Aqua Regia Digestion
Be, Beryllium (ppm) 0.39 0.025 0.36 0.42 Aqua Regia Digestion
Bi, Bismuth (ppm) 0.29 0.015 0.27 0.31 Aqua Regia Digestion
Ca, Calcium (wt.%) 0.593 0.051 0.566 0.621 Aqua Regia Digestion
Cd, Cadmium (ppm) 0.016 0.006 0.007 0.026 Aqua Regia Digestion
Ce, Cerium (ppm) 31.2 2.26 29.8 32.5 Aqua Regia Digestion
Co, Cobalt (ppm) 12.2 1.5 11.4 13.0 Aqua Regia Digestion
Cr, Chromium (ppm) 52 4.7 50 55 Aqua Regia Digestion
Cs, Caesium (ppm) 0.72 0.10 0.66 0.78 Aqua Regia Digestion
Cu, Copper (ppm) 19.4 1.59 18.3 20.6 Aqua Regia Digestion
Dy, Dysprosium (ppm) 1.60 0.084 1.49 1.72 Aqua Regia Digestion
Er, Erbium (ppm) 0.71 0.054 0.64 0.79 Aqua Regia Digestion
Eu, Europium (ppm) 0.63 0.057 0.55 0.71 Aqua Regia Digestion
Fe, Iron (wt.%) 2.36 0.195 2.27 2.46 Aqua Regia Digestion
Ga, Gallium (ppm) 2.75 0.42 2.48 3.01 Aqua Regia Digestion
Gd, Gadolinium (ppm) 2.43 0.26 2.08 2.79 Aqua Regia Digestion
Ge, Germanium (ppm) < 0.10 IND IND IND Aqua Regia Digestion
Hf, Hafnium (ppm) 0.41 0.05 0.38 0.44 Aqua Regia Digestion
Hg, Mercury (ppm) 0.018 0.006 0.010 0.026 Aqua Regia Digestion
Ho, Holmium (ppm) 0.28 0.020 0.26 0.31 Aqua Regia Digestion
In, Indium (ppm) 0.024 0.004 0.019 0.029 Aqua Regia Digestion
K, Potassium (wt.%) 0.133 0.023 0.121 0.145 Aqua Regia Digestion
La, Lanthanum (ppm) 14.8 1.35 14.0 15.6 Aqua Regia Digestion
Li, Lithium (ppm) 7.57 1.05 6.98 8.17 Aqua Regia Digestion
Lu, Lutetium (ppm) 0.073 0.005 0.066 0.080 Aqua Regia Digestion
Mg, Magnesium (wt.%) 0.704 0.067 0.672 0.736 Aqua Regia Digestion
Mn, Manganese (wt.%) 0.021 0.002 0.020 0.022 Aqua Regia Digestion
Mo, Molybdenum (ppm) 1.28 0.079 1.17 1.38 Aqua Regia Digestion
Na, Sodium (wt.%) 0.088 0.014 0.079 0.098 Aqua Regia Digestion
Nb, Niobium (ppm) 0.37 0.08 0.30 0.44 Aqua Regia Digestion
Nd, Neodymium (ppm) 15.2 1.46 13.1 17.2 Aqua Regia Digestion
Ni, Nickel (ppm) 57 3.3 55 59 Aqua Regia Digestion
P, Phosphorus (wt.%) 0.051 0.002 0.050 0.052 Aqua Regia Digestion
Pb, Lead (ppm) 6.76 0.369 6.41 7.11 Aqua Regia Digestion
Pd, Palladium (ppb) < 10.0 IND IND IND Aqua Regia Digestion
Pr, Praseodymium (ppm) 3.65 0.256 3.29 4.02 Aqua Regia Digestion
Rb, Rubidium (ppm) 8.58 1.23 7.83 9.33 Aqua Regia Digestion
Re, Rhenium (ppm) < 0.001 IND IND IND Aqua Regia Digestion
S, Sulphur (wt.%) 0.012 0.003 0.008 0.015 Aqua Regia Digestion
Sb, Antimony (ppm) 0.42 0.05 0.38 0.45 Aqua Regia Digestion
Sc, Scandium (ppm) 2.30 0.34 2.07 2.53 Aqua Regia Digestion
Se, Selenium (ppm) < 1.00 IND IND IND Aqua Regia Digestion
Sm, Samarium (ppm) 3.05 0.244 2.62 3.48 Aqua Regia Digestion
Sn, Tin (ppm) 1.00 0.091 0.92 1.07 Aqua Regia Digestion
Sr, Strontium (ppm) 39.7 3.47 37.9 41.5 Aqua Regia Digestion
Ta, Tantalum (ppm) < 0.010 IND IND IND Aqua Regia Digestion
Tb, Terbium (ppm) 0.32 0.025 0.29 0.35 Aqua Regia Digestion
Te, Tellurium (ppm) < 0.10 IND IND IND Aqua Regia Digestion
Th, Thorium (ppm) 5.75 0.296 5.52 5.98 Aqua Regia Digestion
Ti, Titanium (wt.%) 0.102 0.024 0.090 0.115 Aqua Regia Digestion
Tl, Thallium (ppm) 0.067 0.010 0.058 0.075 Aqua Regia Digestion
U, Uranium (ppm) 0.58 0.021 0.56 0.61 Aqua Regia Digestion
V, Vanadium (ppm) 19.5 2.0 18.3 20.7 Aqua Regia Digestion
W, Tungsten (ppm) 0.36 0.05 0.32 0.41 Aqua Regia Digestion
Y, Yttrium (ppm) 7.18 0.406 6.93 7.44 Aqua Regia Digestion
Yb, Ytterbium (ppm) 0.54 0.047 0.49 0.60 Aqua Regia Digestion
Zn, Zinc (ppm) 32.8 4.8 30.2 35.3 Aqua Regia Digestion
Zr, Zirconium (ppm) 17.7 1.24 16.8 18.6 Aqua Regia Digestion
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