

Workers walk on a heap of coal at a stockyard of an underground coal mine in the Mahanadi coal fields at Dera, near Talcher town in the eastern Indian state of Orissa March 28, 2012. India sits on the world's fifth-largest coal reserves, and produces the most after China and the US. Rupak De Chowdhuri/Reuters
Coal miners and their families shout slogans during a protest march between the mining towns and Oviedo, northern Spain July 20, 2012. The miners are protesting against the government's proposal to decrease funding for coal production. Eloy Alonso/Reuters
Gold miners form a human chain while digging a pit at the Chudja mine in the Kilomoto concession near the village of Kobu, in north-eastern Congo, February 23, 2009. Civil conflict in Congo has been driven for more than a decade by the violent struggle for control over the country's natural resources, including gold, diamonds and timber, most of which is exploited using manual labor. Finbarr O'Reilly/Reuters
A laborer smiles as he finishes his shift of unloading coal at a power plant in Shenyang, Liaoning province November 4, 2010. Sheng Li/Reuters
A worker uses the tapping process to separate nickel ore from other elements at the nickel processing plant owned by PT Vale Indonesia,Tbk in Sorowako of Indonesia's South Sulawesi Province, March 1, 2012. Yusuf Ahmad/Reuters
Women sit in a former coal mine known as 'El Chiflon del Diablo' (The devil's draught), as they stage a hunger strike near Lota town south of Santiago November 17, 2010. The rally was held against the end of a special employment program for victims of the earthquake in Chile. Jose Luis Saavedra/Reuters
Greenpeace environmental activists display a banner in front of the giant excavator in the CSA coal mine near the town of Most November 28, 2011. Activists protested against expansion of coal mining in the area. David W Cerny/Reuters
A plane flies in the distance above the Soviet-era Monument to Coal Miners in the Kazakhstan city of Karaganda. The economy of Karaganda is heavily dependent on nearby coal mines operated by Luxembourg-based mining company ArcelorMittal. Peter Leonard/AP
Miners watch as the drill machine 'Sissi' break through the rock at the final section Faido-Sedrun, at the construction site of the NEAT Gotthard Base Tunnel October 15, 2010. With a length of 35 miles crossing the Alps, the world's longest train tunnel should become operational at the end of 2017. Reuters
People carry baskets of coal scavenged illegally at an open-cast mine in the village of Bokapahari in the eastern Indian state of Jharkhand, Jan. 7, 2011. Kevin Frayer/AP
Coal mine worker Joackim Myhrvang waves while on his way to work in Mine 7 in Svalbard March 26, 2012. Berit Roald/Reuters
A miner holds a pink diamond known as the Argyle Pink Jubilee in East Kimberley, Western Australia February 22, 2012. Mining group Rio Tinto has unearthed an extremely rare pink diamond, Australia's biggest pink rough diamond weighing 12.76 carats at its Argyle mine. Rio Tinto/Reuters
A man walks past a mural about mining in Turon, northern Spain, an area that thrived for more than a century from local coal mining, February 1, 2012. Turon now holds one of the highest unemployment rates in the mining areas of northern Spain, according to local unemployment data. Eloy Alonso/Reuters
Paramilitary policemen guard a tunnel entrance at the Hongfa Coal Mine where 15 miners were killed and three others hurt when the mine carriages they were in plunged into a tunnel, in Nanyang township, Leiyang city, in southern China's Hunan province, Thursday, Feb. 16, 2012. AP
Illegal miners dig in the earth in search of gold in a makeshift camp for illegal mining near Tumeremo in Venezuela's southern Bolivar state in this July 15, 2010. Carlos Garcia Rawlins/Reuters
A worker of the coal mine 'Auguste Victoria' is pictured during his underground work in the western city of Marl, June 28, 2011. The contrast between Germany's record levels of employment and the dire jobs situation elsewhere in Europe is stark. Ina Fassbender/Reuters
A Bolivian mine worker is seen inside the Itos silver and base metals mine in the outskirts of Oruro, Bolivia, February 17, 2012. David Mercado/Reuters