Anchorage Daily News

WASILLA -- It took months of nearly round-the-clock work and moving enough material to fill tens of thousands of dump trucks. But a construction crew managed to smother yet another chunk of a stubborn underground coal fire smoldering near Sutton for the past four decades.

A Cruz Construction crew wrapped up work ahead of schedule this year, snuffing out fires in 30 acres near Slipper Lake, just two miles from downtown Sutton.

The crews tediously dug up, carted off, cooled and sculpted more than 500,000 cubic meters, or about 81,000 dump truck loads, of old coal spoils.

Only some hydroseeding work remains to be done next summer, said Joe Wehrman, a state Department of Natural Resource employee overseeing the cleanup.

The work builds on previous efforts to extinguish the noxious fires, which have been burning since before the mines, once among the state's busiest, were closed in the late 1960s. Six million tons of coal was pulled from the Wishbone Hill area, much of it sold to fuel Anchorage power plants. Another construction crew previously extinguished fires in an adjacent 21 acres. So far, the effort has cost about $6 million, which has been funded through taxes on current mining operations across the country, said Wehrman.

Still more reclamation work remains at the site. Fires continue to burn in another 10 acres nearby, and in areas higher up in the hills, he said. Some derelict buildings dating back to mining days also need to be removed, and some partially collapsed mining shafts need to be filled in, although two containing bear dens will be left alone, he said.

Work at the site may sound like overkill, but is typical of work around the country at former coal mining sites. Once begun, coal fires are notoriously difficult to extinguish. One in Centralia, Pa., proved so resilient the state paid millions to move much of the town. Typical firefighting tools like water are ineffective on coal fires. The blazes burn so hot the heat splits the water molecules, fueling the fire with oxygen, Wehrman said.

Although no one can say for sure how the fires in Sutton got started, former mine workers have said they remember fighting the smoldering blazes even before the mines closed. The fires are concentrated largely in a pile where miners used to dump coal not suitable to sell, Wehrman said.

While the fires in Sutton have not harmed anyone, they are considered a hazard because of the noxious fumes that sometime spew from the ground, and the potential for the blaze to start a forest fire. State officials also worry about people falling into pits created by the coal burning underneath the ground, Wehrman said.

While some interest remains in mining the area, the Wishbone Hill area is more popular today as a recreational site for four-wheelers, bikers and fossil hunters.