OREAS 928b

OREAS 928b 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 928b 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.