An international association (despite its name) of professional geologists interested in locating, understanding, and exploiting petroleum resources around the world. (
http://www.aapg.org
)
Site devoted to amateur gold prospecting, but also contains some information on gold occurrences around the world. (
http://www.klws.com/gold/gold.html
)
No pun intended, the Chamber of Mines, South Africa regulates mining activity in the richest country (with repsect to mineral resources) on Earth. (
http://www.bullion.org.za/welkome.html
)