OREAS 240c

OREAS 240c is a mid-grade gold certified reference material produced from a blend of gold-bearing ore from the Frogs Leg district and a large proportion of barren greenstone host rock. The Frogs Leg ore components originate from Frogs Leg Gold Mine, located west of Kalgoorlie in the Eastern Goldfields Province of Western Australia. The deposit comprises steeply dipping, laminated quartz-sulphide veins and breccia zones occurring along sheared volcanic–basalt contacts. Mineralisation is characterised by native gold associated with pyrite, pyrrhotite, and accessory chalcopyrite. The barren fraction consists of finely milled Cambrian greenstone, providing a stable and compositionally compatible matrix for mid-range Au grades.

OREAS 240c has been characterized using the following methods:

• Gold by Pb collection fire assay (25-50g charge weight) with AAS and ICP-OES finish
• Gold by Bi collection fire assay (30 g charge weight) with AAS finish
• Gold by PhotonAssay™
• Gold by 15-50g aqua regia digestion with ICP-MS and AAS finish
• Gold by cyanide leach (20-200g) with AAS or ICP-MS finish
• Full ICP-OES and ICP-MS elemental suites by 4-acid (HNO3-HF-HClO4-HCl) digestion
• Full ICP-OES and ICP-MS elemental suites by aqua regia digestion

Certified values for applicable analytes are operationally defined for each method, with results under OREAS ISO 17034 scope of accreditation.