OREAS 287

OREAS 287 is one of a suite of six gold ore CRMs (OREAS 284 to OREAS 289) prepared from a blend of Gounkoto ore and barren granodiorite. The ore was sourced from the Loulo-Gounkoto Complex in Western Mali. The certification program includes:

  • Au by 25-40g fire assay with ICP-OES or AAS finish;
  • Gold by Chrysos’ PhotonAssay™ (protocol PAAU02) on ~310g sample weights (15 laboratories);
  • Au by aqua regia digestion (10-50g sample weight) with AAS or ICP finish;
  • Au by cyanide leach (5-200g sample weight) with ICP or AAS finish;
  • Full elemental suites by 4-acid (HCl-HNO3-HF-HClO4) digestion with ICP-OES and MS finish, including over range analytes by ore-grade 4A digestion;
  • Full elemental suites by aqua regia digestion with ICP-OES and MS analysis, including over range analytes by ore-grade AR digestion;
  • Total S by IR combustion furnace (Leco).
Analyte Certified Value 1SD Expanded Uncertainty Low Expanded Uncertainty High Method
Au, Gold (ppm) 3.79 0.139 3.75 3.83 Pb Fire Assay
Au, Gold (ppm) 3.88 0.112 3.85 3.92 PhotonAssay
Au, Gold (ppm) 3.67 0.134 3.61 3.72 Aqua Regia Digestion (sample weights 10-50g)
Au, Gold (ppm) 3.67 0.147 3.60 3.73 Cyanide Leach
Ag, Silver (ppm) 0.119 0.013 0.102 0.137 4-Acid Digestion
Al, Aluminium (wt.%) 7.28 0.294 7.03 7.54 4-Acid Digestion
As, Arsenic (ppm) 1469 51 1422 1516 4-Acid Digestion
Ba, Barium (ppm) 874 36 844 904 4-Acid Digestion
Be, Beryllium (ppm) 2.14 0.082 2.03 2.25 4-Acid Digestion
Bi, Bismuth (ppm) 0.65 0.062 0.54 0.76 4-Acid Digestion
Ca, Calcium (wt.%) 2.51 0.096 2.44 2.59 4-Acid Digestion
Cd, Cadmium (ppm) 0.16 0.02 0.13 0.19 4-Acid Digestion
Ce, Cerium (ppm) 66 4.3 63 70 4-Acid Digestion
Co, Cobalt (ppm) 26.6 1.40 25.6 27.6 4-Acid Digestion
Cr, Chromium (ppm) 55 3.0 51 58 4-Acid Digestion
Cs, Caesium (ppm) 8.62 0.429 8.22 9.02 4-Acid Digestion
Cu, Copper (ppm) 70 2.7 67 72 4-Acid Digestion
Dy, Dysprosium (ppm) 3.56 0.125 3.30 3.83 4-Acid Digestion
Er, Erbium (ppm) 1.44 0.079 1.31 1.57 4-Acid Digestion
Eu, Europium (ppm) 1.34 0.037 1.26 1.42 4-Acid Digestion
Fe, Iron (wt.%) 4.80 0.153 4.65 4.95 4-Acid Digestion
Ga, Gallium (ppm) 19.5 1.15 18.6 20.4 4-Acid Digestion
Gd, Gadolinium (ppm) 5.41 0.214 5.04 5.78 4-Acid Digestion
Hf, Hafnium (ppm) 1.96 0.126 1.82 2.10 4-Acid Digestion
Ho, Holmium (ppm) 0.60 0.037 0.55 0.65 4-Acid Digestion
In, Indium (ppm) 0.083 0.008 0.074 0.092 4-Acid Digestion
K, Potassium (wt.%) 2.90 0.100 2.82 2.98 4-Acid Digestion
La, Lanthanum (ppm) 31.8 2.56 30.0 33.7 4-Acid Digestion
Li, Lithium (ppm) 46.3 2.54 44.6 48.0 4-Acid Digestion
Lu, Lutetium (ppm) 0.18 0.011 0.16 0.20 4-Acid Digestion
Mg, Magnesium (wt.%) 1.78 0.057 1.71 1.84 4-Acid Digestion
Mn, Manganese (wt.%) 0.046 0.002 0.044 0.048 4-Acid Digestion
Mo, Molybdenum (ppm) 2.91 0.188 2.62 3.21 4-Acid Digestion
Na, Sodium (wt.%) 1.66 0.051 1.61 1.72 4-Acid Digestion
Nb, Niobium (ppm) 10.4 0.38 10.0 10.9 4-Acid Digestion
Nd, Neodymium (ppm) 30.7 1.27 28.5 32.9 4-Acid Digestion
Ni, Nickel (ppm) 27.9 1.23 26.8 28.9 4-Acid Digestion
P, Phosphorus (wt.%) 0.077 0.003 0.075 0.080 4-Acid Digestion
Pb, Lead (ppm) 18.7 1.61 17.4 20.0 4-Acid Digestion
Pr, Praseodymium (ppm) 7.92 0.367 7.31 8.52 4-Acid Digestion
Rb, Rubidium (ppm) 134 10 126 142 4-Acid Digestion
S, Sulphur (wt.%) 1.30 0.059 1.26 1.35 4-Acid Digestion
Sb, Antimony (ppm) 0.77 0.055 0.71 0.83 4-Acid Digestion
Sc, Scandium (ppm) 9.54 0.539 9.11 9.98 4-Acid Digestion
Sm, Samarium (ppm) 6.27 0.242 5.63 6.90 4-Acid Digestion
Sn, Tin (ppm) 3.66 0.189 3.45 3.87 4-Acid Digestion
Sr, Strontium (ppm) 132 6 128 136 4-Acid Digestion
Ta, Tantalum (ppm) 0.86 0.053 0.81 0.92 4-Acid Digestion
Tb, Terbium (ppm) 0.70 0.032 0.65 0.76 4-Acid Digestion
Te, Tellurium (ppm) 0.21 0.03 0.15 0.26 4-Acid Digestion
Th, Thorium (ppm) 12.1 0.44 11.6 12.6 4-Acid Digestion
Ti, Titanium (wt.%) 0.327 0.013 0.316 0.337 4-Acid Digestion
Tl, Thallium (ppm) 0.74 0.035 0.70 0.77 4-Acid Digestion
Tm, Thulium (ppm) 0.19 0.006 0.19 0.20 4-Acid Digestion
U, Uranium (ppm) 3.96 0.376 3.46 4.46 4-Acid Digestion
V, Vanadium (ppm) 72 3.2 70 75 4-Acid Digestion
W, Tungsten (ppm) 20.1 0.98 18.9 21.4 4-Acid Digestion
Y, Yttrium (ppm) 15.3 0.83 14.5 16.1 4-Acid Digestion
Yb, Ytterbium (ppm) 1.22 0.094 1.12 1.33 4-Acid Digestion
Zn, Zinc (ppm) 65 2.6 63 68 4-Acid Digestion
Zr, Zirconium (ppm) 62 5.1 59 66 4-Acid Digestion
Ag, Silver (ppm) 0.117 0.008 0.104 0.129 Aqua Regia Digestion
Al, Aluminium (wt.%) 2.22 0.156 2.12 2.31 Aqua Regia Digestion
As, Arsenic (ppm) 1442 64 1395 1488 Aqua Regia Digestion
Ba, Barium (ppm) 351 67 308 393 Aqua Regia Digestion
Be, Beryllium (ppm) 1.34 0.14 1.22 1.46 Aqua Regia Digestion
Bi, Bismuth (ppm) 0.67 0.064 0.55 0.79 Aqua Regia Digestion
Ca, Calcium (wt.%) 1.56 0.075 1.50 1.61 Aqua Regia Digestion
Cd, Cadmium (ppm) 0.066 0.012 0.048 0.083 Aqua Regia Digestion
Ce, Cerium (ppm) 29.5 4.8 26.7 32.4 Aqua Regia Digestion
Co, Cobalt (ppm) 25.9 1.80 24.6 27.1 Aqua Regia Digestion
Cr, Chromium (ppm) 53 2.6 51 55 Aqua Regia Digestion
Cs, Caesium (ppm) 6.95 0.420 6.65 7.26 Aqua Regia Digestion
Cu, Copper (ppm) 70 3.3 68 72 Aqua Regia Digestion
Dy, Dysprosium (ppm) 2.34 0.209 2.04 2.65 Aqua Regia Digestion
Er, Erbium (ppm) 0.90 0.10 0.77 1.03 Aqua Regia Digestion
Eu, Europium (ppm) 0.42 0.10 0.29 0.55 Aqua Regia Digestion
Fe, Iron (wt.%) 4.66 0.225 4.51 4.82 Aqua Regia Digestion
Ga, Gallium (ppm) 9.70 0.724 9.18 10.21 Aqua Regia Digestion
Gd, Gadolinium (ppm) 3.15 0.70 2.19 4.12 Aqua Regia Digestion
Ge, Germanium (ppm) 0.11 0.03 0.08 0.14 Aqua Regia Digestion
Hf, Hafnium (ppm) 0.32 0.029 0.29 0.34 Aqua Regia Digestion
Ho, Holmium (ppm) 0.36 0.033 0.32 0.40 Aqua Regia Digestion
In, Indium (ppm) 0.069 0.005 0.061 0.077 Aqua Regia Digestion
K, Potassium (wt.%) 0.871 0.056 0.836 0.906 Aqua Regia Digestion
La, Lanthanum (ppm) 12.9 2.2 11.5 14.4 Aqua Regia Digestion
Li, Lithium (ppm) 39.5 1.77 37.9 41.2 Aqua Regia Digestion
Lu, Lutetium (ppm) 0.090 0.004 0.079 0.100 Aqua Regia Digestion
Mg, Magnesium (wt.%) 1.70 0.072 1.65 1.75 Aqua Regia Digestion
Mn, Manganese (wt.%) 0.043 0.002 0.042 0.044 Aqua Regia Digestion
Mo, Molybdenum (ppm) 2.73 0.30 2.50 2.96 Aqua Regia Digestion
Na, Sodium (wt.%) 0.125 0.016 0.113 0.137 Aqua Regia Digestion
Nb, Niobium (ppm) 0.73 0.22 0.59 0.87 Aqua Regia Digestion
Ni, Nickel (ppm) 26.2 1.35 25.3 27.2 Aqua Regia Digestion
P, Phosphorus (wt.%) 0.062 0.002 0.060 0.064 Aqua Regia Digestion
Pb, Lead (ppm) 4.14 0.49 3.81 4.46 Aqua Regia Digestion
Rb, Rubidium (ppm) 81 5.9 77 85 Aqua Regia Digestion
Re, Rhenium (ppm) 0.002 0.000 0.001 0.003 Aqua Regia Digestion
S, Sulphur (wt.%) 1.29 0.061 1.23 1.34 Aqua Regia Digestion
Sb, Antimony (ppm) 0.36 0.07 0.32 0.40 Aqua Regia Digestion
Sc, Scandium (ppm) 7.94 0.493 7.63 8.25 Aqua Regia Digestion
Se, Selenium (ppm) 0.76 0.15 0.54 0.99 Aqua Regia Digestion
Sn, Tin (ppm) 2.60 0.223 2.45 2.76 Aqua Regia Digestion
Sr, Strontium (ppm) 20.5 2.2 19.3 21.6 Aqua Regia Digestion
Ta, Tantalum (ppm) < 0.010 IND IND IND Aqua Regia Digestion
Tb, Terbium (ppm) 0.45 0.020 0.41 0.49 Aqua Regia Digestion
Te, Tellurium (ppm) 0.19 0.02 0.15 0.23 Aqua Regia Digestion
Th, Thorium (ppm) 5.04 0.92 4.46 5.62 Aqua Regia Digestion
Ti, Titanium (wt.%) 0.213 0.018 0.202 0.224 Aqua Regia Digestion
Tl, Thallium (ppm) 0.50 0.025 0.47 0.53 Aqua Regia Digestion
U, Uranium (ppm) 2.88 0.249 2.50 3.25 Aqua Regia Digestion
V, Vanadium (ppm) 61 2.4 59 63 Aqua Regia Digestion
W, Tungsten (ppm) 10.4 1.4 9.6 11.2 Aqua Regia Digestion
Y, Yttrium (ppm) 9.55 0.690 9.09 10.01 Aqua Regia Digestion
Yb, Ytterbium (ppm) 0.66 0.045 0.58 0.74 Aqua Regia Digestion
Zn, Zinc (ppm) 61 3.1 59 63 Aqua Regia Digestion
Zr, Zirconium (ppm) 8.43 0.673 7.94 8.92 Aqua Regia Digestion
S, Sulphur (wt.%) 1.29 0.040 1.27 1.32 Infrared Combustion
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