OREAS 62h was prepared from coarse reject splits of gold-silver ore samples blended with barren andesite. The gold-silver ore was sourced from the Cracow mine located 500km northwest of Brisbane in Queensland, Australia. The barren andesite was sourced from the Carboniferous Blair Duguid Hypersthene Andesite intrusive, located 70kms northwest of Newcastle, Australia. Cracow is a low sulphidation epithermal deposit hosted by meta-andesitic volcanics. High grade gold mineralisation occurs within fissure quartz veins and is associated with zones of silicification, present as quartz lode breccia and as quartz vein breccia.
Twenty-nine analytical laboratories participated in the program to certify the elements reported below. The following methods were employed:
- Au by lead collection fire assay with AAS (23 laboratories) or ICP-OES (6 laboratories) finish;
- Gold by aqua regia digestion on 10-50g sample weights with ICP-OES and/or ICP-MS (12 laboratories) and AAS (6 laboratories);
- 4-acid (HF-HNO3-HClO4-HCl) digestion for full ICP-OES and ICP-MS elemental suites (up to 26 laboratories depending on the element);
- Aqua regia digestion for full ICP-OES and ICP-MS elemental suites (up to 26 laboratories depending on the element).
Instrumental neutron activation analysis for Au on 20 x 85mg subsamples was also undertaken at ANSTO, Lucas Heights to confirm homogeneity.
| CRM Code |
Principle Certified Values |
State |
Matrix |
Mineralization |
| OREAS 62h |
Au 10.54ppm |
Ag 7.69ppm |
Cu 144ppm |
primary |
meta-andesite |
low sulphidation epithermal |