OREAS 291 was prepared from a blend of high-grade gold-antimony ore and barren metasediments. The ore was sourced from the Costerfield Operation (owned by Mandalay Resources Ltd) located approximately 10km northeast of the town of Heathcote in Victoria, Australia. Twenty-two commercial analytical laboratories participated in the program to certify the following:
- Au by 25-50g fire assay with AAS or ICP-OES finish;
- Au by 15-30g aqua regia digestion with ICP-MS, AAS or ICP-OES finish;
- Sb by peroxide fusion with ICP-OES or ICP-MS finish (and one laboratory used pressed powder pellet with XRF finish);
- Full ICP-OES and MS elemental suites by 4-acid digestion;
- Full ICP-OES and MS elemental suites by aqua regia digestion;
- Instrumental neutron activation analysis (INAA) for Au on 20 x 85mg subsamples to confirm homogeneity (undertaken by the Australian Nuclear Science and Technology Organisation (ANSTO)).
| |
Analyte
|
Certified Value
|
1SD
|
CRM State
|
Matrix
|
Mineralisation
|
| |
Au by fire assay
|
4.20 g/t
|
0.124
|
primary
|
metasediments
|
orogenic lode gold
|
| |
Sb by Na2O Fusion |
1.50 % |
0.076 |
primary |
metasediments |
orogenic lode gold |