Mining as a human activity dates back many thousands of years in various parts of the world Recently, the earliest example of mining in the Americas was an iron oxide mine in Chile dating back to around 10,000 BC(a).
Mining in Atlantis is recorded by Plato in Critias 114e where he states that there were many mines producing orichalcum as well as other metals. Mrs. Whishaw contended that the pre-Roman copper mines of Southern Spain was the source of the Atlantean orichalcum.

However, the most extensive ancient mines were probably those of the Upper Peninsula of Michigan where copper mining was carried on between 3000 and 1200 BC. It has been guesstimated that up to 1.5 billion pounds of the metal was extracted. It is further speculated that much of this was used to feed the Bronze Age needs of Europe and the Mediterranean^(b)(c).

(a) http://www.eurekalert.org/pub_releases/2011-05/uocp-auo051811.php

^(b) http://www.grahamhancock.com/forum/WakefieldJS1.php

^(c) http://www.superiorreading.com/copperhistory.html