On average, 50 to 60 coal miners die in this country every year while they work. It is such a dangerous job that miners wear emergency breathing devices at all times in order to help give them enough time to escape a disaster.
In addition to cave-ins and explosions, miners face dangers they cannot see, from carbon monoxide to methane gas.It is the reason miners of previous generations brought canaries into mines with them. If the canary began to struggle – or died – they knew they might be in trouble.
Today's emergency air packs are not foolproof. In the Sago mine disaster of 2006, Randal McCloy, the only survivor, said four of them failed. Twelve miners died there.
Last week in China, where safety regulations are less strict than in the U.S., more than 100 miners survived eight days beneath the ground after a mine shaft collapsed. Chinese officials called their survival a "miracle."
More than 2,600 Chinese coal miners died in accidents last year, which was an improvement over the 6,995 deaths recorded in 2002, the most dangerous year recorded by official government figures.
One Chinese miner described how he managed to survive beneath the ground by eating sawdust and tree bark and drinking the murky water. Some other miners said they resorted to hanging from shaft walls by their belts to avoid falling into the water when they slept. They later climbed into a mining cart that went by.
Kevin Stricklin of U.S. Coal Mine Safety believes methane was the most-likely cause of the explosion yesterday in West Virginia's Upper Big Branch mine, run by the Massey Energy Co. He thinks the gas seeped into the area where 31 men were working. It then likely mixed with coal dust, which is highly volatile. Just one spark in that environment could have caused a very powerful explosion.
Stricklin told ABC News, "[the Upper Big Branch mine] has a lot of methane." He said methane should have been ventilated to prevent an explosion.
Such an explosion can be horrific. The governor of West Virginia, Joe Manchin, said, "Rail cars and buggies and heavy equipment, train rails … looked like they had been twisted like a pretzel."
Even after the explosion, there was so much leftover gas and smoke that rescuers had to leave the mine before finding four of the missing miners. Three of them were working near where six bodies were found, and the other was near where more bodies were discovered.
After the Sago mine disaster, new safety measures were ordered. Safety chambers, where miners could take refuge, were added. They were required to hold enough air, food, and water for four days. Officials at Upper Big Branch say they hope the four missing miners Monday were able to escape to one of those chambers before succumbing to toxic gases.
However, even with the inherent dangers involved in coal mining, half of this country's electricity comes from coal, so the industry is not likely to disappear anytime soon.