For the newbies. Something close to home to provide some perspective. Note the miserable grade, but still an operating gold mine. The grades at Tres Estados and Ema are
500 times richer than Boddington:
The Boddington goldmine's gold (
[email protected]/t Au for
1160t Au) is related to diorite (medium-grained gabbro) intrusions (purple) .
"The Wandoo deposit is interpreted as a structurally-controlled, intrusion-related, Au-Cu deposit, formed by two overprinting magmatic-hydrothermal systems. The first has ‘porphyry-like’ characteristics,
associated with dioritic intrusion at ~2700 Ma, the other coeval with a barren post-tectonic granitoid at ~2612 Ma. Although gold is associated with both events, the main stage, particularly the high-grade mineralisation, appears synchronous with the latter (McCuaig
et al., 2001)."
http://www.portergeo.com.au/database/mineinfo.asp?mineid=mn221