OREAS 320

OREAS 320 is a certified reference material produced from a blend of zinc-lead-silver ores and concentrates sourced from several Australian mining operations. Key contributors include Zn-Pb-Ag ores from the George Fisher Mine at Mount Isa (Glencore), Mt Isa and Dugald River zinc concentrates, and a high-grade lead concentrate from the Rosebery Mine in Tasmania. These materials represent diverse mineralisation styles, including SEDEX-type deposits hosted within carbonaceous dolomitic sediments of the Urquhart Shale Formation in NW Queensland and volcanogenic massive sulphide (VMS) mineralisation at Rosebery. A minor proportion of barren black slate was included to assist in balancing matrix composition, and a specially prepared silver-rich blend—produced by combining silver granules with rhyodacite, granite, and quartz sand—was used to elevate the silver content.

OREAS 320 has been characterized using the following methods:

• Major elements by borate/ oxidising fusion with XRF finish
• LOI at 1000 °C using a muffle furnace or thermogravimetric analyser (TGA)
• Full ICP-OES and MS elemental suites by peroxide fusion
• Full ICP-OES and MS elemental suites by 4-acid (HCl-HNO3-HF-HClO4) digestion
• Full ICP-OES and MS elemental suites by aqua regia digestion
• Total C and Total S by infrared combustion furnace

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