CRC LEME
Open File Report 4
ABSTRACT
Morphology and geochemistry of gold in a laterite profile, Reedy
Mine, Western Australia
Freyssinet, P. and Butt, C.R.M.
The morphology and geochemistry of gold grains panned from bulk
samples collected from various horizons of the weathering profile
of gold mineralisation at the North Rand Pit at Reedy have been
studied. The primary mineralization in the main lode is characterised
by xenomorphic and euhedral grains containing 6-16% Ag and 300-1000ppm
Cu. The gold in lateral veins is similar but coarser. In the saprolite,
only a few residual, Ag-rich, primary grains remain, and these are
strongly etched and rounded. The other grains are Ag- and Cu-free
and appear to be secondary. In the ferruginous horizon, all the
grains are secondary, being Ag- and Cu-free and having characteristic
prismatic or flat pseudo-hexagonal morphologies; most are partly
etched. Iron and As are present in many secondary grains, probably
as micro-inclusions, suggesting that Fe plays an important role
in the process of remobilisation and precipitation.
Last updated: Tuesday, January 04, 2000 10:08 AM
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