OREAS 60c

OREAS 60c was prepared from coarse reject splits of gold-silver ore samples from the Cracow mine located 500km northwest of Brisbane in Queensland, 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-six commercial analytical laboratories participated in the program to characterise Au and Ag. The following methods were employed:

  • Au by 26 labs via fire assay with AAS (21 labs) or ICP-OES (5 labs) finish;
  • Instrumental neutron activation analysis for Au on 20 x 1g subsamples to confirm homogeneity (1 lab);
  • Ag via four acid digestion with ICP-OES (17 labs), AAS (4 labs) or ICP-MS (3 labs) finish except for 2 labs that used a 3-acid digestion;
  • S was also determined via four acid digestion with ICP-OES (5 labs);
  • Ag by 24 labs via aqua regia digestion with ICP-OES (18 labs), ICP-MS (4 labs) or AAS (2 labs) finish;
  • Au by 15 labs via aqua regia digestion with ICP-MS (8 labs), AAS finish (4 labs), graphite furnace AAS (2 labs) or solvent extraction AAS (1 lab) finish.
Analyte Certified Value 1SD 95% Confidence Limits Low 95% Confidence Limits High Method
Au, Gold (ppm) 2.47 0.082 2.44 2.50 Pb Fire Assay
Ag, Silver (ppm) 4.87 0.223 4.78 4.96 4-Acid Digestion
Au, Gold (ppm) 2.45 0.114 2.40 2.51 Aqua Regia Digestion
S, Sulphur (wt.%) 0.860 0.031 0.821 0.898 4-Acid Digestion
Ag, Silver (ppm) 4.81 0.296 4.68 4.93 Aqua Regia Digestion
Downloads
Certificate DataPack SDS NRAM (412 KB)
Archived

This CRM is no longer available.
Information is provided for reference only.

Specifications