Origin of Material: This standard is a blend of Ventersdorp Contact Reef, Carbon Leader Reef and Vaal Reef material provided by Anglo Gold Ashanti in South Africa. It was made from a mixture of pulp reject sample material, collected during routine underground sampling, sourced from mine assay laboratories and blended down to a required grade with silica.
Approximate Mineral and Chemical Composition: The major gangue mineral is quartz with minor pyrite, uraninite and thucolite. Gold occurs primarily as discrete grains. Trace element chemistry data from 12 of the labs has been compiled but has not been certified. Summary statistics for this data are set out in the appendix
Recommended Concentrations and Limits.
(at two Standard Deviations)
Au Pb Collection 2.66 ± 0.14 g/t
U M/ICP 95 ± 9 ppm
Specific Gravity 2.71 ± 0.06
U XRF 88 ± 14 ppm