The environmental toll of underground mining is significant. It includes air pollution, changes in water-flow patterns, chemical and gas seepage into water supplies and soil, inaccessible fires in abandoned mines, and dramatic changes in land composition that can make the area unusable after the mining operation is done [source: Saxena].
Then there is the human toll. Most mining accidents gain little media attention, especially those involving few casualties or taking place in developing nations. In 2010, almost 2,500 Chinese miners died on the job, none of those attributed to "major accidents" [source: Macia].
That year was a terrible one for mining in general. In the United States, a mining catastrophe in West Virginia left 29 dead, the same number that died in an accident in New Zealand. In Chile, 33 miners were rescued in the dramatic incident recounted earlier, but another 45 died in other accidents that same year [source: Macia].
Many accidents occur when the mine props collapse due to earth tremors. Explosions, too, trigger casualties when ventilation systems fail to effectively remove exhaust from mining equipment, coal dust and natural underground gas leaks. Blasting can ignite those gases, leading to deaths from both the explosions themselves and the subsequent collapse of mine structures; a methane-gas explosion killed those 29 miners in West Virginia [source: Macia].
Long-term health problems are a serious job risk, as well. Continually breathing in mineral dust can cause lung diseases like pneumoconiosis or the dreaded black lung. Breathing in welding fumes, radon or mercury (often found in mines) also causes respiratory diseases. Hearing loss from noisy equipment and back injuries from lifting heavy loads are also common [source: Live Science].
Most countries now have laws and regulations designed to address safety and environmental issues. Some require the mining company to return the mined area close to its original state. Others require mines to be inspected regularly to ensure they are safe. And new mining techniques have also decreased the death toll. In the U.S., the mining industry saw thousands of deaths from accidents each year in the early 1900s. This dropped to about a hundred per year in the 1990s, and just 35 in 2012 [source: Mine Safety and Health Administration]. China had 7,000 mining deaths in 2002 but 2,500 in 2010 [source: Macia].
While safety has definitely increased in developed countries, it still has a long way to go in some developing countries. But we may see a day when underground mines aren't some of the most frightening factories on Earth. Anywhere.