7 year old Soni has a basket of coal lifted onto her head by her mother, 28 year old Savita, after having scavenged coal illegally from an open-cast coal mine in the village of Bokapahari on February 08, 2012 near to Jharia, India. (Photo by Daniel Berehulak /Getty Images)

Boys play basketball in the facilities of Belarus' Republican Clinic of Speleotherapy within a salt mine, as part of their treatment, near the town of Soligorsk, south of Minsk, February 19, 2015. According to the state clinic, more than 7,000 children and adults seek medical treatment for respiratory illness each year in the subsurface chambers of its facilities, located 420 metres underground between layers of potassium and stone salts in an operational salt mine. (Photo by Vasily Fedosenko/Reuters)

Medics help a rescued miner after an explosion and fire at a coal mine killed at least 17 miners and left up to 300 workers trapped underground, in Soma, in western Turkey, Tuesday, May 13, 2014, a Turkish official said. Twenty people were rescued from the mine but one later died in the hospital, Soma administrator Mehmet Bahattin Atci told reporters. The town is 250 kilometers (155 miles) south of Istanbul. The death toll was expected to rise. (Photo by AP Photo/Depo Photos)

The old church of Geamana village is seen partially submerged by polluted water tainted with cyanide and other chemicals near Rosia Montana, central Romania, March 24, 2014. (Photo by Bogdan Cristel/Reuters)

A illegal gold miner of Kamoro people, Tinus, pan for gold on February 4, 2017 in Timika, Papua Province, Indonesia. Indonesia produces over 70 billion dollars in gold a year and is home to the largest gold mine and the third largest copper mine in the world, the Grasberg mine, which is located at West Papua. (Photo by Ulet Ifansasti/Getty Images)

Traditional miners carry sulphur on the Ijen volcano complex on May 25, 2009 outside Banyuwangi, East Java, Indonesia. Miners carry the solidified yellow sulphur blocks from the crater floor to the rim for as many hours a day as they can tolerate, paid by the kilogram of sulphur they extract. The average wage is USD $.05 per kilogram of sulphur and a worker, depending on his strength and stamina, carry on average 3 baskets of 70-80kg per day, earning him around USD $11. (Photo by Ulet Ifansasti/Getty Images)

Police officers standby while a forest fire burns the hills of Valparaiso city, northwest of Santiago, March 13, 2015. Several hectares of land has been burned due to forest fires near Valparaiso city, with no report of deaths or injuries, local authorities said. (Photo by Lucas Galvez/Reuters)

A woman holds a rooster burned during a fire on a hill, where more than 100 homes were burned due to a forest fire but there have been no reports of death, local authorities said in Valparaiso, Chile January 2, 2017. (Photo by Rodrigo Garrido/Reuters)