A miner who works illegally at a gold concession owned by AngloGold Ashanti shows a shaft dug by hand in Obuasi, Ghana, July 7, 2016. Picture taken July 7, 2016. REUTERS/Matthew Mpoke Bigg

A miner who works illegally at a gold concession owned by AngloGold Ashanti shows a shaft dug by hand in Obuasi, Ghana, July 7, 2016. Picture taken July 7, 2016. REUTERS/Matthew Mpoke Bigg

A miner who works illegally at a gold concession owned by AngloGold Ashanti shows a shaft dug by hand in Obuasi, Ghana, July 7, 2016. Picture taken July 7, 2016. REUTERS/Matthew Mpoke Bigg

A gold miner climbs down into a mine shaft in Manica Province near the Zimbabwe border September 18, 2010. Hundreds of miners work in individual claims rented from local landowners.
REUTERS/ Goran Tomasevic (MOZAMBIQUE - Tags: SOCIETY EMPLOYMENT BUSINESS)

A gold miner smiles as he climbs down into a mine shaft in Manica Province, near the Zimbabwe border, September 18, 2010. Hundreds of miners work in individual claims rented from local landowners.
REUTERS/Goran Tomasevic (MOZAMBIQUE - Tags: EMPLOYMENT BUSINESS IMAGES OF THE DAY SOCIETY)

GUINEA-MINE/COLLAPSE - Map of Guinea locating Siguiri where at least 14 illegal gold miners were killed on Wednesday when disused mineshafts they were working on collapsed. RNGS. (SIN02)

A worker walks inside a mine in El Corpus May 23, 2008. In the mountains of southern Honduras, hundreds of small-scale miners are scraping out tiny quantities of increasingly precious gold but their fervour could be threatening their lives and the environment. To match feature MINING/ILLEGAL-HONDURAS REUTERS/Edgard Garrido (HONDURAS)

A miner carries his tools as he walks out of a tunnel in a traditional gold mine in Cikotok, Indonesia's Banten province July 2, 2008. Picture taken July 2, 2008. REUTERS/Dadang Tri (INDONESIA)

Mining executives stand before the headframe of first mineshaft drilled at the Oyu Tolgoi copper and gold mine in Mongolia November 10, 2007. Mining firms are telling Mongolia's parliament to unlock the country's mining sector by taking a landmark decision on a multi-billion dollar copper deal. Oyu Tolgoi's potential was enough to make geologists' eyes bulge on a recent tour of the site, where traditional Mongolian white tents stand alongside thousands of crates containing 720 km of drill core -- rock drilled out during the exploration phase. Picture taken November 10, 2007. REUTERS/Tom Miles (MONGOLIA)

Workers prepare the site of the second mineshaft to be sunk at Oyu Tolgoi in the South Gobi desert in Mongolia November 10, 2007. Mining firms are telling Mongolia's parliament to unlock the country's mining sector by taking a landmark decision on a multi-billion dollar copper deal. Oyu Tolgoi's potential was enough to make geologists' eyes bulge on a recent tour of the site, where traditional Mongolian white tents stand alongside thousands of crates containing 720 km of drill core -- rock drilled out during the exploration phase. Picture taken November 10, 2007. REUTERS/Tom Miles (MONGOLIA)

Workers prepare the site of the second mineshaft to be sunk at Oyu Tolgoi in the South Gobi desert in Mongolia November 10, 2007. Mining firms are telling Mongolia's parliament to unlock the country's mining sector by taking a landmark decision on a multi-billion dollar copper deal. Oyu Tolgoi's potential was enough to make geologists' eyes bulge on a recent tour of the site, where traditional Mongolian white tents stand alongside thousands of crates containing 720 km of drill core -- rock drilled out during the exploration phase. Picture taken November 11, 2007. REUTERS/Tom Miles (MONGOLIA)

A miner inspects a mine shaft on the outskirts of Tocopilla some 1,559 km (968 miles) north of Santiago November 15, 2007. A powerful earthquake hit mineral-rich northern Chile on Wednesday, killing at least two people, injuring more than 100 and halting output at some of the world's largest copper mines. REUTERS/Ivan Alvarado (CHILE)

A miner inspects a mine shaft in the outskirts of Tocopilla, some 1559 km (968 miles) north of Santiago, November 15, 2007. Powerful aftershocks rattled northern Chile on Thursday, startling residents and emergency workers a day after a large earthquake killed two people and injured more than 100 in the mineral-rich region. REUTERS/Ivan Alvarado (CHILE)

France's UMP political party presidential candidate Nicolas Sarkozy leaves the Wendel mineshaft after a campaign visit in Petite-Roselle, eastern France, April 17, 2007. REUTERS/Philippe Wojazer (FRANCE)

France's UMP political party presidential candidate Nicolas Sarkozy speaks with former miners during a campaign visit at the Wendel mineshaft in Petite-Roselle, eastern France, April 17, 2007. REUTERS/Philippe Wojazer (FRANCE)

France's UMP political party presidential candidate Nicolas Sarkozy shares a laugh with a former coal miner who offered him a hammer during a campaign visit at the Wendel mineshaft in Petite-Roselle, eastern France, April 17, 2007. REUTERS/Philippe Wojazer (FRANCE)

France's UMP party presidential candidate Nicolas Sarkozy listens to speeches as he is surrounded by former miners during a campaign visit at the Wendel mineshaft in Petite-Roselle, eastern France April 17, 2007. REUTERS/Philippe Wojazer (FRANCE)

France's UMP party presidential candidate Nicolas Sarkozy listens to speeches as he is surrounded by former miners during a campaign visit at the Wendel mineshaft in Petite-Roselle, eastern France April 17, 2007. REUTERS/Philippe Wojazer (FRANCE)

France's UMP party presidential candidate Nicolas Sarkozy (L) shares a laugh with a former coal miner who offered him a hammer during a campaign visit at the Wendel mineshaft in Petite-Roselle, eastern France April 17, 2007. REUTERS/Philippe Wojazer (FRANCE)

Relative of seven murdered businessmen wait in the office of Mustafa Batduyev, the leader of the Karachayevo-Cherkessia region, demanding his resignation, in the region's capital Cherkessk, November 10, 2004. The small, mainly Muslim Karachayevo-Cherkessia region has been hit by protests since the disappearance last month of seven businessmen in which the regional leader Mustafa Batduyev's son-in-law is a prime suspect. The discovery of their bodies in a mineshaft sparked fresh riots on Tuesday when protesters stormed into government headquarters in the regional capital Cherkessk and demanded Batdyyev quit. REUTERS/Eduard Kornienko CVI/JV

Relative of a murdered businessman waits in the office of Karachayevo-Cherkessia region leader in Cherkessk. A relative of one of seven murdered businessmen waits in the office of Mustafa Batduyev, the leader of the Karachayevo-Cherkessia region, demanding his resignation, in the region's capital Cherkessk, November 10, 2004. The small, mainly Muslim Karachayevo-Cherkessia region has been hit by protests since the disappearance last month of seven businessmen in which the regional leader Mustafa Batduyev's son-in-law is a prime suspect. The discovery of their bodies in a mineshaft sparked fresh riots on Tuesday when protesters stormed into government headquarters in the regional capital Cherkessk and demanded Batdyyev quit. REUTERS/Eduard Kornienko

U.S. President George W. Bush speaks at a fundraiser for Mike Fischer,
the Republican party nominee for Governor in Pittsburg, Pennsylvania,
August 5, 2002. Earlier in the day, Bush also met with 9 mine workers
who were rescued from a flooded mineshaft. REUTERS/Win McNamee

WM

U.S. President George W. Bush is greeted by Mike Fischer (R), the
Republican party nominee for Governor in Pennsylvania, August 5, 2002
during a fundraiser for Fischer. Earlier in the day, Bush also met with
9 mine workers who were rescued from a flooded mineshaft. REUTERS/Win
McNamee

WM/JP

FOR RELEASE WITH STORY BC-CHINA-DAM-ENVIRONMENT - A coal miner in Santuo village in China's southwestern province of Sichuan oils the wheels of a cart before going into the mineshaft to retrieve another load of coal. The massive Three Gorges dam being built in neighbouring Hubei province will create a 600 kilometer (366 mile) long lake that will submerge thousands of old factories, garbage dumps and mines such as this one. Many of those living along the river worry that pollution from such sites, in addition to sewage water from towns along the river, will turn the reservoir in to one giant cesspool. Picture taken 28OCT97.

CHINA DAM ENVIRONMENT