Thursday, December 6, 2007

Danger Underground? Coal Mining in Utah

You may have seen the news headlines this summer: six coal miners and three rescue workers were killed when part of the Crandall Canyon Mine, in central Utah, collapsed. (You may even have seen our blog entry about it.) Across the US, around 30 of the more than 79,000 coal miners are killed in accidents at work each year.

If mining can be dangerous, why do we still do it? What makes it risky? How do miners stay safe?

Why do we mine coal? One word: power. Burning coal generates almost 90% of Utah’s electricity. Despite talk about clean, renewable sources of energy, the fact remains that coal is plentiful, cheap, and constant. In the short term, at least, coal is here to stay.

Where’s the risk? Extracting coal in Utah is like scraping the frosting from inside a complex layer cake that’s been smashed, stretched, sat on, and buried. Staying safe means ensuring the tunnels through the coal don’t collapse while people are still using them. But coal is the weakest layer, and the forces on it from the surrounding rock can be uneven and unpredictable. Also, the coal is buried deep, as far as 3,000 feet below the mountainous surface.

To stay safe, miners leave big pillars of coal supporting the roof above their heads. When they finish a section, they collapse the roof to relieve some of the pressure. Sophisticated machines do much of the dirty work, meaning fewer people in harm’s way. Still, it’s a difficult business. “These miners are going places that nobody’s been since the dinosaurs lived on Earth,” says Dave Tabet, of the Utah Geological Survey. “Like astronauts, they accept an inherent risk.”

A typical Utah coal mine. After extracting coal from an area, miners let small sections of roof collapse behind them to relieve pressure from the surrounding rock layers.

Want to know more? Follow the links below for more information about coal mining, Crandall Canyon, and mining in Utah.