Dave Latoski first heard about the Tantalus Butte fire in the winter of 1988-89, when Carmacks residents noticed subsidences around the nearby coal mine.

At the time, the Department of Indian Affairs and Northern Development was responsible for mine safety in the Yukon, Latoski explains. As a DIAND employee, he went to Carmacks to investigate.

Latoski found cracks in the ground and steam rising up from the snow high on the butte. In places, depressions were appearing as the ground settled over burnt-out or mined out coal seams. Beneath the ground, out of sight and out of reach, coal was clearly smouldering.

The owners of the coal lease were asked to put up a perimeter fence but they said that they were still actively extracting coal and the fence would hinder their activities. Instead, DIAND had the lease owner block access roads to the site and put up warning signs near the subsidence location, which was well away from heavily travelled areas.

"The coal lease was still active, so the signs were the limit of what we could do," Latoski explains.

In October 2000 Latoski, now DIAND's Regional Manager of Mining Inspections, went back to Tantalus Butte. He and a colleague began walking in to the site of the subsidence but stopped when they couldn't see where they were going because of chest-high grass still growing on the fire-warmed hillside. They decided to survey the site by helicopter rather than on foot.

It was a good decision, Latoski says, pointing at a blurry aerial photograph of the site. Just beyond where he turned back is the newest of a series of sinkholes that have appeared over the underground fire. The helicopter hovered over the hole, he says, but the shaft twists so much that he couldn't see how far down it went.

"I wouldn't want to fall in there and find out," he adds. "Nobody knows how deep these things are."

Impressive as the hole is, the Tantalus Butte coal fire is minor by world standards. Coal burns easily and coal seams exposed to the air are likely to ignite spontaneously. Generally the fires burn until they run out of coal.

In northern China, one of the world's major coal producing regions, some underground fires have been burning for hundreds of years. A group of researchers studying the fires estimate that about 200 million tons of coal are consumed by spontaneous combustion each year in China, about ten times what the country exports annually.

An underground coal fire has been burning for decades beneath the former town of Centralia, Pennsylvania. Closer to home, in the Northwest Territories, exposed coal seams in the Smoking Hills where the Horton River flows into the Arctic Ocean have been burning off and on for centuries.

The Tantalus Butte fire isn't that old. Yukon historian Ken Spotswood says the old Tantalus Butte coal mine, which once provided fuel for the riverboats, caught fire in 1978, ten years before Dave Latoski first saw it. By then the mine had been operating only sporadically for several decades.

In its day, however, it was an important part of Yukon history. George Carmack built a trading post at the foot of Tantalus Butte in 1893, with the idea of developing the coal seam he found there. Three years later he helped discover gold in the Klondike, and the idea of a coal mine lost its charm. His brief flirtation with coal mining is commemorated today in the name of Carmacks, the town that grew up near his post and his coal deposit.

For more information about the Tantalus Butte fire, call Dave Latoski, DIAND Yukon Region, (867) 667-3211. To learn about the Tantalus Butte coal mine, go to Ken Spotswood's brief history of Carmacks at www.yukonalaska.com/communities/carmackshist.html. A web site created by coal fire researcher Anupta Prakash at www.itc.nl/~prakash/coalfire/index.html offers information about the environmental impact of coal fires around the world.