OREAS 926b

OREAS 926b prepared from material from the CSA mine located near the town of Cobar in central western New South Wales, Australia. The copper ore body is hosted by the Early Devonian CSA Siltstone, a thinly bedded turbiditic sequence of carbonaceous siltstones and mudstones with minor coarser units. The CSA Siltstone is part of the Cobar Supergroup, consisting of lower syn-rift sediments and upper post-rift sag phase sediments. The mineralisation is structurally controlled and confined to a number of steeply dipping bodies within a major shear zone on the eastern margin of the Early Devonian Cobar Basin. It is characterised by low-grade greenschist alteration and epigenetic low-grade mineralisation enveloping higher-grade shoots of vein complexes or sub-massive to massive sulphides. The sulphides include chalcopyrite, pyrrhotite, pyrite, sphalerite, galena, bornite and cubanite. Iron-rich chlorite and silica are prominent alterations in the siltstone host.

OREAS 926b 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.