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;
- 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).
| CRM Code |
Principle Certified Values |
State |
Matrix |
Mineralization |
| OREAS 251b |
Au 0.505 g/t |
Cu 26.7 ppm |
Ag 0.123 ppm |
oxide |
weathered greenstone |
orogenic lode gold |