Description
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Origin of Material
The standard was made using material from the Witwatersrand Basin.
Approximate Mineral and Chemical Composition
Throughout the Witwatersrand, gold ores occur in sheets or reefs originally deposited horizontally under water. The thickness of the reefs range between a lie of grit to several meters, with an average of 300mm. The sediments were also intersected by dykes and sills of dolomite, diabase and syenite intruding existing faults. The reefs can be in the form of either course conglomerates, rock pebbles and cemented in a silicate matrix. Pebbles usually derived from vein quarts, may also consist of quarzitic, chert jasper and quartz porphyry. The matrix consists of pure silica, but also contains minute flakes of muscovite and pyrophyllite as well as visible pyrite and other sulphides. The gold is usually confined to the matrix and tends to be concentrated along bedding planes (Vermeulen, 2001).
Summary Statistics
Recommended Concentrations and Limits (at two Standard Deviations)
Certified Concentrations
Au Pb Collection 4.82 0.42 g/t
U 4A_MICP 24 2 ppm
C Combustion/LECO 3268 101 ppm
S Combustion/LECO 0.74 0.03 %
LOI LOI 3.22 0.39 %
SG SG 2.87 0.11 Dimensionless
Co 4A_MICP 47 10 ppm
Cu 4A_MICP 71 11 ppm
Fe XRF 4.50 0.19 %
K 4A_MICP 1.17 0.10 %
K XRF 1.10 0.068 %
Mo 4A_MICP 2 0.1 ppm
Ni 4A_MICP 308 46 ppm
Zr 4A_MICP 77 10 ppm
Major Oxides
Certified Concentrations (at two Standard Deviations)
U3O8 4A_MICP 0.003 0.0002 %
Al2O3 XRF 7.76 0.12 %
CaO XRF 1.35 0.069 %
Fe2O3 XRF 6.43 0.28 %
K2O XRF 1.33 0.082 %
MgO XRF 3.39 0.067 %
SiO2 XRF 74.79 1.4 %
