Eric Baccega / Young men holding their torches in their mouth while digging 10 meters underground in the coltan mines of Muhanga, Rwanda. This mineral is radioactive and these young miners are killing their lungs by...

Bryan and Cherry Alexander / Old mining train in Ny Alesund. It is the most northerly train in the world, but now has nowhere to go. Spitsbergen, Svalbard, Norway, June 2008.

Bryan and Cherry Alexander / Old mining train in Ny Alesund, Spitsbergen, Norway, June 2006.

Bernard Castelein / Women panning for gold, Dairane, Madagascar, June 2013.

Eric Baccega / Miner with hands full of coltan metallic ore, Muhanga coltan mines, Rwanda, Africa, March 2009

Pete Oxford / Aerial view of Alluvial Gold Mine in the rainforest, Guyana , December 2009

John Cancalosi / Magnetite (FeO4, ferrous and ferric oxide), an important ore of iron that is naturally magnetic. Yinnietharra, Western Australia

Inaki Relanzon / A man looking down a gold exctraction hole. Daraina protected area, North Madagascar, Africa, November 2010.

Juergen Freund / Aerial view of Rio Tuba nickel mine, Palawan, Philippines, April 2010.

Juergen Freund / Women mining corals for a living. They work a 10-hour day to mine 2 boatloads of coral. Each boatload makes them 80,000 Rupiah (8 US dollars). Wanci, Wakatobi, Sulawesi, Indonesia, November 2009.

Juergen Freund / Bajau / Bajo woman mining corals. These women work a 10-hour day to mine 2 boatloads of coral. Each boatload makes them 80,000 Rupiah (8 US dollars). Wanci, Wakatobi, Sulawesi, Indonesia, November 200...

John Cancalosi / Selenite (CaSO4-2H2O, Hydrous Calcium sulfate), a crystalline form of gypsum. The massive form of gypsum, found in alabaster, is widespread and commercially important, used for the manufacture of plas...