Ann: Anomalous Co Cu Ni & Ag XRF Values in Massive Sulphides, page-180

Having logged some 10Kms of core from Tropicana the massive pyrite intersected in the water bores bears no resemblance in form.


The image above has 3 core photos. The one with the red star is what I remember as possible ore. Rather innocuous looking rock with wispy biotite and 1-3% finish grained pyrite along fractures. Still most of the zones like this grade enough to have produced a 7-10 Moz Au deposit.

IGO and Anglo nearly walked away from Tropicana (2005+-) because the core looked so boring after the last round of what ended up being discovery drilling. The assays surprised most everyone I gather and the rest is history [Hopefully some in the making for DUN??]. Anecdotal so treat with care.

Proximity of Au and Ni.?
Beta Hunt at Kambalda is an example as is the area to the south of it where there are Au (St Ives Au complex) and Ni (Baker (Lunnon metals recent announcements) and LanFranchi to the south). However, the ultramafic (Komatiitic flows) style is different to what is possible for DUN (chronolithic g abbro etc..

Au in proximity to ultramafics? Tends to be competency contrast and shearing that is focused along the contacts rather than the ultramafics or hosts themselves. Simplistic view that may not stand much scrutiny.
Some examples
WA - Garden Well (50+Mt in open pit and looks like UG may be possible) Hemi (Duicon Eagle area - fortuitous? perhaps), Sandstone (the Lords area). Probably others.
Canada - Red Lake high grade.



tip of iceberg for geological comment on the Q as to why pyrite and ultramafics at Central and perhaps Matilda S.

Patience is needed with diamond drilling. There may be a pot of Ni and Cu somewhere down there.