DATE-TIME
Date(s) - Tuesday, 10/06/2014
6:30 pm - 8:00 pm
Category(ies)
GPIC Talk for June 2014
Speaker Martin Hughes
The sediment-hosted Long Canyon deposit of Newmont has a resource of 2.2 M oz at ~2.3 g/t Au but is still open along strike (Smith et al. 2013). It is more than 150 km east of the Carlin trend and unlike Carlin deposits to the west occurs in a platform carbonate rather than continental slope environment, the Cambro- Ordovician rocks having undergone low-grade Mid-Mesozoic orogenesis and then brittle, extensional deformation in the Cainozoic. It is mainly in limestone which encloses an 80 m thick dolomite layer, and occurs in calcareous and Fe- As dissolution breccias, pervasively silicified, localized in structurally-complex areas such as minor faults and fold hinges at the dolomite interface (including at boudin-block margins and boudin necks). The ore is thoroughly oxidized by weathering to the more than 300 m depth drilled, but is anomalous in Sb, Th, Hg and As and appears to have formed from fine-grained pyrite + marcasite + arsenopyrite mineralisation (similar to Carlin-type deposits).
About the Presenter
Martin Hughes completed a Doctorate on central African ores at the University of the Witwatersrand in 1986, worked with various companies including those of Newmont and North Ltd throughout Africa, North America, Australia and elsewhere, and is now a Ballarat-based consultant working in Australia and overseas, primarily in gold exploration (and research) but also in uranium, base metals and tungsten. This talk results from a recent visit to Long Canyon and a number of other Nevada deposits with Moira Smith, and comparisons are made with these deposits.
Nibblies from 6.30pm, Presentation 7.10pm (approx.)
$5 Members, $10 Non-Members, Students Free
