40-Year Coal Fire: Contractor Tries to Put Out Smoldering in Underground Mine Spoils

By S.J. Komarnitsky, Anchorage Daily News, Alaska

Jun. 14–JONESVILLE MINE — The coal mines that made Sutton and fueled Anchorage power plants for years are mostly a fading memory now.

Mine shafts are covered with sheet metal to keep out the curious; the only pickaxes working seams these days are carried by fossil hunters.

But the miners left behind a legacy that is still being dealt with today — a swath of underground coal fires that have burned for more than 40 years.

This summer a Cruz Construction crew is digging up 29 acres near Slipper Lake just two miles from downtown Sutton where miners once dumped coal not suitable to sell.

Fires have burned in the pile, which is up to 70 feet deep, for decades, and state officials estimate it could burn for another couple hundred years if left untouched.

The fires are a legacy of the mining heyday here, when more than 1,200 workers tunneled and stripped coal from seams along Wishbone Hill. Six million tons of coal, much of it sold to fuel power plants in Anchorage, was pulled from the hills before the mines closed in the late 1960s.

Some coal, however, was too powdery or too laden with rock to be sold. Miners dumped it in a spoils, or waste, pile that over time grew to 60 acres.

At some point, the pile caught fire and has been burning ever since, according to state Natural Resources Department officials.

Much of the time the blaze smolders underground nearly undetectable. But occasionally it pops to the surface charring adjacent rocks a whitish red and sending acrid smoke wafting through nearby neighborhoods.

A few years ago it sparked a small forest fire, said Roger Allely, a state hydrogeologist who mapped the coal fires and is helping oversee the cleanup.

State officials worry the underground blazes could start a larger forest fire, or someone could get hurt walking around on top of it, Allely said. The state already spent $2.5 million to have a crew dig up and extinguish fires in a 21-acre section.

The latest work covers 29 acres, and is costing about $3.5 million, all of which is being paid with taxes on current coal mining operations, he said.

While more than $100,000 an acre may sound pricey, coal fires are notoriously difficult to put out. The coal burns so hot that dousing it with water actually feeds the fire, Allely said. The heat splits the atoms in water, and the resulting oxygen fuels the flames, he said.

Just turning the pile of coal over also does little, he said. Coal can spontaneously combust and can easily be restarted by a campfire or lightning.

The only sure way to put out the fire is to dig up every inch of the pile, in this case nearly 500,000 cubic meters, or about 81,000 dump-truck loads.

The crews then spread the material out, cool it, compact it, and eventually will lay a two-foot-thick clay cap to keep it from reigniting, Allely said.

There are no shortcuts, said Joe Wehrman, another Natural Resources Department employee overseeing the work.

No one knows exactly when the blaze started or how. Miners have told state officials the spoils pile caught fire before the mine closed down in the late 1960s.

Walt Mayr, now living near Sutton, worked at the Jonesville Mine as a master mechanic for more than 20 years. He said he remembers the fire burning before he left.

Mayr said miners sprayed the blaze with fire hoses, then later used rollers to compact the ground, which they thought put it out.

Allely said they likely just drove it underground.

“They probably had it out on the surface, but you know they never dug it up,” he said. “It’s an animal. It probably moved around on them.”

Fortunately the fire in Jonesville remains relatively small.

Coal fires are legendary for their size and resilience. In Pennsylvania, the state has paid millions to move much of the town of Centralia, once home to 1,100 residents, after a coal fire started in 1962 caused roads to collapse and threatened homes with toxic fumes.

In China, Dutch scientists have estimated underground coal fires consume up to 120 million tons of coal a year and release enough gas to account for 3 percent of the worldwide production of carbon dioxide.

Allely, who helped design the cleanup project in Sutton, said he drilled 62 holes over five years to map the fires in the spoils pile. During that time, he measured temperatures of more than 450 degrees, he said.

Some of hottest spots he found 70 feet below the surface where water runs along the surface of a clay layer, he said. He speculated the water is supplying oxygen to the fire.

The heat from the fire keeps some areas snow free year round, he said, showing pictures taken of barren slopes during a previous winter.

Even as he mapped it, the fire moved, making it impossible to pinpoint, he said.

Cruz Construction project manager Jeff Miller, at 28 younger than the fire he is extinguishing, said he didn’t know what to expect when he bid on the job.

“I just had visions of fire erupting everywhere,” he said.

So far, though, the work has been mostly about moving earth and less about fighting fire.

Ten hours a day, six days a week, his crew has been digging up and moving the 70-foot deep pile of coal spoils. On a recent day, the work resembled a merry-go-round with a trio of side dumpers running a circuit from an excavator digging out the coal pile to a nearby area where the trucks dumped their loads before returning.

Hot spots were few and far between. But occasional hot clouds of steam engulfed a bulldozer working the pile and an acrid turpentinelike smell wafted through the area.

The hottest spot crews have hit is 340 degrees, Miller said, which isn’t bad considering road-paving projects regularly reach those kinds of temperatures.

Still he has to worry about hazards not typical in other construction jobs. With fires burning underneath, the ground could subside beneath the heavy equipment, he said.

Crews also have to take special precautions because of toxic gases that escape from the fires. The excavator is outfitted with a carbon monoxide detector and has a GPS system mounted on it so crews can pinpoint its location.

Miller said crews plan to be finished by next summer. But that will be far from the end of the cleanup work at the mine area

The state still has plans to dig up another 10 acres, and has lots of other work at the site from filling in old mining shafts to cutting down dangerously sheer cliffs left behind by miners stripping the coal, Allely said.

—–

Copyright (c) 2006, Anchorage Daily News, Alaska

Distributed by Knight Ridder/Tribune Business News.

For reprints, email tmsreprints@permissionsgroup.com, call 800-374-7985 or 847-635-6550, send a fax to 847-635-6968, or write to The Permissions Group Inc., 1247 Milwaukee Ave., Suite 303, Glenview, IL 60025, USA.