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.

Uncovering Utah's Deep Sea Mysteries

500 million years ago, there were jellyfish living in western Utah. Hard to believe, isn't it? To start with, western Utah is terrible jellyfish habitat - there are no oceans for hundreds of miles! If you went there today, you'd have a hard time finding anything that swims at all, much less a deep-water, ocean-loving creature like a jellyfish. On top of that, 500 million years is a very long time - how do we know what was there?

These are some good questions, and luckily there are good answers. We know that jellyfish were there because two geologists from the University of Utah found them. Or, to be precise, they found fossilized traces of the creatures' remains. Researchers Richard D. Jarrard and Susan Halgedahl spent time cracking open rocks at the fossil site west of Delta, where other ancient animal traces had been seen before. They were pretty excited by what they found - the remains of four different species of ancient jellyfish.

"It's hard to imagine anything more difficult to create a fossil from than a jellyfish that's less than half an inch in size...They just don't have any hard parts at all," Jarrard told the Deseret Morning News. Most of the time, their soft bodies decay and become part of the environment around them, even in areas where the conditions are right for preserving fossil traces of harder material like bones or shells. But not this time.

Why not? And how were there jellyfish in western Utah at all? While today it's a desert - dry as a bone - for hundreds of millions of years, starting around 570 million B.C., western Utah was under the ocean. California and Nevada weren't around, and the west coast of North America ran right through our now-desert state. In the deep water over the present-day fossil site, the jellyfish swam, ate, bred, and died. And for a while during those hundreds of millions of watery years, the guck at the bottom of the western Utah ocean was just right for a jelly to float down and leave its mark. That ocean bottom became the Marjum formation of sedimentary rock, where the jellyfish fossils were found.


After finding the fossils, Jarred and Halgedahl sent them to experts at the University of Kansas, who determined that the fossils are related to modern jellyfish, are much older than any jellyfish fossils ever found before, and are also surprisingly sophisticated. That's exciting for scientists trying to work out the mystery of how life started on Earth, giving them important clues to life in the oceans way far back in time. Hurray for the jellies!


What might the landscape where you live have looked like 500 million years ago? How could you know?

The Earth moves fast in Yellowstone

Quick, look down! The ground is moving!

Can't feel anything? That's because the movement of the Earth's surface is usually pretty slow by human standards. North America, for example, is floating around the planet at about 2 centimeters per year, as fast as your fingernails grow. The Earth's surface is in constant motion, squishing up mountains as land masses run into each other, stretching open deep underwater, and sliding down under continents to be melted by the planet's hot interior. If you could watch Earth's 4.5 billion year history in fast-forward, it would bustle with activity. In your lifetime, though, most of the changes will be too slow to see, other than the occasional abrupt events like earthquakes and volcanoes.

But not in Yellowstone National Park. Yellowstone is one of the most geologically active places in the world, providing unique opportunities to observe change happen fast enough to notice in a lifetime. Small earthquakes rumble through more than once a day (on average); hot water and steam burble from the ground and then shift to a new spot; geysers erupt regularly then stop, or lie dormant and suddenly start again; and according to new findings just released by the University of Utah, the ground swells and recedes like a slowly breathing giant.

In the course of 2.5 years, from July 2004 to December 2006, the Utah geologists used satellites to measure the exact elevation of the caldera, or giant volcanic crater, that lies within the Park, both by bouncing radar beams down and back up to orbit, and by communicating with receivers stationed on the ground. In that time, the land rose 18 centimeters (7 inches), growing faster than your average human child, and three times faster than anyone had seen it grow before.

The scientists attribute this quick expansion to a pancake-shaped blob of molten rock the size of Los Angeles, gurgling six miles underground. This blob of magma originated as part of a "hotspot," or gigantic plume of hot molten rock, that starts 400 miles beneath Earth's surface, travels up through the Earth's layers, then spreads out to a 300-mile pool lying 30 miles underground. From there, hot magma sometimes breaks off, rises up, and fills a chamber below the Park. It's the heat from that chamber that powers Yellowstone's geysers and keeps it so geologically active, and the magma is likely responsible for the recent uplift.

One thing the scientists say for sure is that it's not a sign of an imminent eruption. So if you want to see our Earth systems in action, pack your bags and head for the Park.