| Description: OREAS 273 was prepared from high-grade oxidised gold ore from the Cortez Mine located in Lander and Eureka County, Nevada, USA. The mine is located on the Carlin Trend approximately 75 miles (120 km) southwest of Elko and is owned by Nevada Gold Mines (operated by Barrick).
Carlin-style gold mineralisation is notorious for its refractory nature. The significant presence of carbonaceous material impedes gold recovery by aqua regia digestion and cyanide leach methods. Matching your standards to the matrix and mineralisation style of your field samples as well as the analytical method used for sample analysis is very important, as a mismatch could result in low gold recovery. Thirty-one commercial analytical laboratories participated in the program to certify the elements shown below. The following methods were employed: - Gold by fire assay (15-40g charge weight) with AAS, ICP-OES or ICP-MS finish (31 laboratories);
- Gold by x-ray photon assay on ~350g sample weights using 4 Chrysos PhotonAssay machines at 3 laboratories. Multiple rounds of data (comprising three or six replicates) were generated by different staff from 3 of the machines;
- Full ICP-OES and ICP-MS elemental suites by aqua regia digestion (up to 25 laboratories depending on the element);
- Full ICP-OES and ICP-MS elemental suites by 4-acid (HNO3-HF-HClO4-HCl) digestion (up to 25 laboratories depending on the element).
Download Certificate OREAS273 Download DataPack OREAS273 | Analyte | Certified Value | 1SD | 95% CI Low | 95% CI High | Method |
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| Ag, Silver (ppm) | 0.646 | 0.027 | 0.596 | 0.695 | 4-Acid Digestion | | Al, Aluminium (wt.%) | 1.65 | 0.097 | 1.6 | 1.71 | 4-Acid Digestion | | As, Arsenic (ppm) | 1211 | 69 | 1166 | 1255 | 4-Acid Digestion | | Ba, Barium (ppm) | 44.3 | 2.22 | 42.8 | 45.7 | 4-Acid Digestion | | Be, Beryllium (ppm) | 0.54 | 0.034 | 0.48 | 0.59 | 4-Acid Digestion | | Bi, Bismuth (ppm) | 0.64 | 0.033 | 0.61 | 0.67 | 4-Acid Digestion | | Ca, Calcium (wt.%) | 19.43 | 1.221 | 18.7 | 20.17 | 4-Acid Digestion | | Cd, Cadmium (ppm) | 0.42 | 0.028 | 0.37 | 0.46 | 4-Acid Digestion | | Ce, Cerium (ppm) | 22.8 | 1.54 | 21.7 | 23.9 | 4-Acid Digestion | | Co, Cobalt (ppm) | 2.21 | 0.139 | 2.07 | 2.34 | 4-Acid Digestion | | Cr, Chromium (ppm) | 32.9 | 4.1 | 30.7 | 35.1 | 4-Acid Digestion | | Cs, Caesium (ppm) | 3.05 | 0.117 | 2.94 | 3.16 | 4-Acid Digestion | | Cu, Copper (ppm) | 20.9 | 1.48 | 19.7 | 22.1 | 4-Acid Digestion | | Dy, Dysprosium (ppm) | 2.95 | 0.15 | 2.81 | 3.09 | 4-Acid Digestion | | Er, Erbium (ppm) | 1.83 | 0.097 | 1.74 | 1.92 | 4-Acid Digestion | | Eu, Europium (ppm) | 0.56 | 0.034 | 0.53 | 0.6 | 4-Acid Digestion | | Fe, Iron (wt.%) | 0.784 | 0.03 | 0.764 | 0.805 | 4-Acid Digestion | | Ga, Gallium (ppm) | 4.45 | 0.35 | 4.19 | 4.71 | 4-Acid Digestion | | Gd, Gadolinium (ppm) | 2.88 | 0.18 | 2.72 | 3.05 | 4-Acid Digestion | | Ge, Germanium (ppm) | 0.14 | 0.03 | 0.1 | 0.18 | 4-Acid Digestion | | Hf, Hafnium (ppm) | 0.9 | 0.072 | 0.8 | 0.99 | 4-Acid Digestion | | Ho, Holmium (ppm) | 0.63 | 0.044 | 0.59 | 0.66 | 4-Acid Digestion | | In, Indium (ppm) | 0.035 | 0.005 | 0.028 | 0.042 | 4-Acid Digestion | | K, Potassium (wt.%) | 0.778 | 0.043 | 0.753 | 0.803 | 4-Acid Digestion | | La, Lanthanum (ppm) | 18.7 | 1.23 | 17.8 | 19.7 | 4-Acid Digestion | | Li, Lithium (ppm) | 11.8 | 0.64 | 11.2 | 12.4 | 4-Acid Digestion | | Lu, Lutetium (ppm) | 0.22 | 0.017 | 0.2 | 0.24 | 4-Acid Digestion | | Mg, Magnesium (wt.%) | 5.19 | 0.215 | 5.06 | 5.33 | 4-Acid Digestion | | Mn, Manganese (wt.%) | 0.041 | 0.001 | 0.04 | 0.042 | 4-Acid Digestion | | Mo, Molybdenum (ppm) | 7.42 | 0.279 | 7.18 | 7.66 | 4-Acid Digestion | | Na, Sodium (wt.%) | 0.031 | 0.006 | 0.029 | 0.034 | 4-Acid Digestion | | Nb, Niobium (ppm) | 3.82 | 0.297 | 3.61 | 4.02 | 4-Acid Digestion | | Nd, Neodymium (ppm) | 13.9 | 0.59 | 13.3 | 14.6 | 4-Acid Digestion | | Ni, Nickel (ppm) | 31.2 | 1.91 | 29.6 | 32.7 | 4-Acid Digestion | | P, Phosphorus (wt.%) | 0.103 | 0.005 | 0.1 | 0.107 | 4-Acid Digestion | | Pb, Lead (ppm) | 12.2 | 0.75 | 11.6 | 12.8 | 4-Acid Digestion | | Pr, Praseodymium (ppm) | 3.57 | 0.164 | 3.37 | 3.78 | 4-Acid Digestion | | Rb, Rubidium (ppm) | 59 | 3.1 | 57 | 62 | 4-Acid Digestion | | Re, Rhenium (ppm) | 0.007 | 0.001 | 0.005 | 0.009 | 4-Acid Digestion | | S, Sulphur (wt.%) | 0.049 | 0.007 | 0.046 | 0.052 | 4-Acid Digestion | | Sb, Antimony (ppm) | 26.7 | 1.02 | 25.3 | 28.2 | 4-Acid Digestion | | Sc, Scandium (ppm) | 4 | 0.252 | 3.79 | 4.2 | 4-Acid Digestion | | Se, Selenium (ppm) | 9.97 | 1.08 | 8.94 | 11 | 4-Acid Digestion | | Sm, Samarium (ppm) | 2.65 | 0.081 | 2.51 | 2.79 | 4-Acid Digestion | | Sn, Tin (ppm) | 0.97 | 0.086 | 0.86 | 1.07 | 4-Acid Digestion | | Sr, Strontium (ppm) | 321 | 19 | 309 | 333 | 4-Acid Digestion | | Ta, Tantalum (ppm) | 0.25 | 0.03 | 0.23 | 0.28 | 4-Acid Digestion | | Tb, Terbium (ppm) | 0.45 | 0.033 | 0.42 | 0.48 | 4-Acid Digestion | | Te, Tellurium (ppm) | 0.21 | 0.03 | 0.17 | 0.25 | 4-Acid Digestion | | Th, Thorium (ppm) | 2.94 | 0.116 | 2.84 | 3.04 | 4-Acid Digestion | | Ti, Titanium (wt.%) | 0.084 | 0.004 | 0.08 | 0.088 | 4-Acid Digestion | | Tl, Thallium (ppm) | 9.47 | 0.363 | 9.12 | 9.83 | 4-Acid Digestion | | Tm, Thulium (ppm) | 0.25 | 0.01 | 0.23 | 0.26 | 4-Acid Digestion | | U, Uranium (ppm) | 6.22 | 0.302 | 5.97 | 6.48 | 4-Acid Digestion | | V, Vanadium (ppm) | 111 | 6 | 107 | 115 | 4-Acid Digestion | | W, Tungsten (ppm) | 10.5 | 0.49 | 10 | 11.1 | 4-Acid Digestion | | Y, Yttrium (ppm) | 24.9 | 1.19 | 23.9 | 25.8 | 4-Acid Digestion | | Yb, Ytterbium (ppm) | 1.57 | 0.086 | 1.49 | 1.65 | 4-Acid Digestion | | Zn, Zinc (ppm) | 46.4 | 3.62 | 44.4 | 48.4 | 4-Acid Digestion | | Zr, Zirconium (ppm) | 31.5 | 4.7 | 28 | 34.9 | 4-Acid Digestion | | Ag, Silver (ppm) | 0.524 | 0.043 | 0.501 | 0.548 | Aqua Regia Digestion | | Al, Aluminium (wt.%) | 0.549 | 0.056 | 0.52 | 0.579 | Aqua Regia Digestion | | As, Arsenic (ppm) | 1215 | 61 | 1182 | 1248 | Aqua Regia Digestion | | Ba, Barium (ppm) | 25.1 | 2.38 | 23.3 | 26.8 | Aqua Regia Digestion | | Be, Beryllium (ppm) | 0.4 | 0.023 | 0.37 | 0.43 | Aqua Regia Digestion | | Bi, Bismuth (ppm) | 0.61 | 0.024 | 0.59 | 0.63 | Aqua Regia Digestion | | Ca, Calcium (wt.%) | 18.56 | 1.328 | 17.73 | 19.39 | Aqua Regia Digestion | | Cd, Cadmium (ppm) | 0.42 | 0.027 | 0.38 | 0.45 | Aqua Regia Digestion | | Ce, Cerium (ppm) | 16.2 | 1.15 | 15.3 | 17 | Aqua Regia Digestion | | Co, Cobalt (ppm) | 2.24 | 0.3 | 2.05 | 2.43 | Aqua Regia Digestion | | Cr, Chromium (ppm) | 22.1 | 1.94 | 21 | 23.3 | Aqua Regia Digestion | | Cs, Caesium (ppm) | 1.42 | 0.2 | 1.29 | 1.56 | Aqua Regia Digestion | | Cu, Copper (ppm) | 20.5 | 1.87 | 19.2 | 21.9 | Aqua Regia Digestion | | Dy, Dysprosium (ppm) | 2.89 | 0.241 | 2.65 | 3.12 | Aqua Regia Digestion | | Er, Erbium (ppm) | 1.72 | 0.117 | 1.61 | 1.83 | Aqua Regia Digestion | | Eu, Europium (ppm) | 0.55 | 0.037 | 0.5 | 0.6 | Aqua Regia Digestion | | Fe, Iron (wt.%) | 0.759 | 0.06 | 0.726 | 0.791 | Aqua Regia Digestion | | Ga, Gallium (ppm) | 1.75 | 0.22 | 1.58 | 1.91 | Aqua Regia Digestion | | Gd, Gadolinium (ppm) | 2.83 | 0.206 | 2.64 | 3.02 | Aqua Regia Digestion | | Ge, Germanium (ppm) | 0.1 | IND | IND | IND | Aqua Regia Digestion | | Hf, Hafnium (ppm) | 0.22 | 0.03 | 0.19 | 0.24 | Aqua Regia Digestion | | Hg, Mercury (ppm) | 96 | 4.2 | 93 | 99 | Aqua Regia Digestion | | Ho, Holmium (ppm) | 0.6 | 0.052 | 0.54 | 0.65 | Aqua Regia Digestion | | In, Indium (ppm) | 0.034 | 0.004 | 0.027 | 0.04 | Aqua Regia Digestion | | K, Potassium (wt.%) | 0.277 | 0.023 | 0.264 | 0.29 | Aqua Regia Digestion | | La, Lanthanum (ppm) | 12.9 | 0.74 | 12.3 | 13.5 | Aqua Regia Digestion | | Li, Lithium (ppm) | 4.37 | 0.427 | 4.09 | 4.65 | Aqua Regia Digestion | | Lu, Lutetium (ppm) | 0.19 | 0.014 | 0.17 | 0.2 | Aqua Regia Digestion | | Mg, Magnesium (wt.%) | 4.87 | 0.176 | 4.75 | 4.99 | Aqua Regia Digestion | | Mn, Manganese (wt.%) | 0.041 | 0.003 | 0.039 | 0.042 | Aqua Regia Digestion | | Mo, Molybdenum (ppm) | 7.36 | 0.617 | 7.01 | 7.7 | Aqua Regia Digestion | | Nb, Niobium (ppm) | 0.11 | 0.02 | 0.09 | 0.14 | Aqua Regia Digestion | | Nd, Neodymium (ppm) | 11.4 | 0.92 | 10.5 | 12.3 | Aqua Regia Digestion | | Ni, Nickel (ppm) | 30.4 | 2.4 | 28.8 | 32 | Aqua Regia Digestion | | P, Phosphorus (wt.%) | 0.1 | 0.011 | 0.094 | 0.106 | Aqua Regia Digestion | | Pb, Lead (ppm) | 12.1 | 1.18 | 11.3 | 12.8 | Aqua Regia Digestion | | Pr, Praseodymium (ppm) | 2.74 | 0.229 | 2.51 | 2.97 | Aqua Regia Digestion | | Rb, Rubidium (ppm) | 20.4 | 2.1 | 18.7 | 22.1 | Aqua Regia Digestion | | Re, Rhenium (ppm) | 0.007 | 0.001 | 0.005 | 0.008 | Aqua Regia Digestion | | S, Sulphur (wt.%) | 0.045 | 0.009 | 0.038 | 0.051 | Aqua Regia Digestion | | Sb, Antimony (ppm) | 19.7 | 2.2 | 18.5 | 21 | Aqua Regia Digestion | | Sc, Scandium (ppm) | 3.87 | 0.4 | 3.57 | 4.16 | Aqua Regia Digestion | | Se, Selenium (ppm) | 8.97 | 0.747 | 8.41 | 9.53 | Aqua Regia Digestion | | Sm, Samarium (ppm) | 2.39 | 0.17 | 2.25 | 2.53 | Aqua Regia Digestion | | Sn, Tin (ppm) | 0.6 | 0.08 | 0.53 | 0.67 | Aqua Regia Digestion | | Sr, Strontium (ppm) | 308 | 26 | 296 | 321 | Aqua Regia Digestion | | Ta, Tantalum (ppm) | 0.01 | IND | IND | IND | Aqua Regia Digestion | | Tb, Terbium (ppm) | 0.44 | 0.033 | 0.41 | 0.47 | Aqua Regia Digestion | | Te, Tellurium (ppm) | 0.2 | 0.04 | 0.18 | 0.23 | Aqua Regia Digestion | | Th, Thorium (ppm) | 2.43 | 0.128 | 2.28 | 2.57 | Aqua Regia Digestion | | Ti, Titanium (wt.%) | 0.008 | 0.002 | 0.006 | 0.009 | Aqua Regia Digestion | | Tl, Thallium (ppm) | 7.52 | 0.77 | 7.08 | 7.96 | Aqua Regia Digestion | | Tm, Thulium (ppm) | 0.23 | 0.008 | 0.21 | 0.24 | Aqua Regia Digestion | | U, Uranium (ppm) | 5.07 | 0.283 | 4.87 | 5.27 | Aqua Regia Digestion | | V, Vanadium (ppm) | 60 | 6 | 57 | 64 | Aqua Regia Digestion | | W, Tungsten (ppm) | 5.12 | 0.456 | 4.82 | 5.41 | Aqua Regia Digestion | | Y, Yttrium (ppm) | 23.2 | 1.32 | 22.3 | 24 | Aqua Regia Digestion | | Yb, Ytterbium (ppm) | 1.41 | 0.13 | 1.3 | 1.53 | Aqua Regia Digestion | | Zn, Zinc (ppm) | 42.9 | 3.1 | 41.3 | 44.6 | Aqua Regia Digestion | | Zr, Zirconium (ppm) | 7.93 | 0.652 | 7.44 | 8.41 | Aqua Regia Digestion | | Au, Gold (ppm) | 10.76 | 0.334 | 10.64 | 10.87 | Pb Fire Assay | | Au, Gold (ppm) | 11.03 | 0.244 | 10.88 | 11.18 | PhotonAssay |
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