In Utah's coal country, it is said mining is the backbone of the state's economy.

"Utah was characterized by President Lincoln as the treasure house of the nation because of our mineral wealth," said David Litvin, the president of the Utah Mining Association, a trade group of mining companies.

Yet that wealth is finite. Mine advocates, scientists and mine officials debate how much is really left in coal-rich Carbon and Emery counties. But it could be decades before there is any real worry.

At the Crandall Canyon Mine, where six miners are trapped, there may not be much coal left to harvest. The tragedy of the mine collapse may not help.

"The mine is running short of resources, so this will probably hasten the ultimate closure of that mine if they have to close off a portion of that mine because it's not safe," said Dave Tabet, the energy and minerals program director for the Utah Geological Survey.

According to the latest coal report prepared by the UGS, the Crandall Canyon Mine was scheduled to close next year. Longwall mining equipment used in the Crandall Canyon Mine already had been sent to another mine near Helper.

"Genwal is currently pulling pillars in Crandall Canyon and plans to close the mine in 2008," the report said.

An updated report due to be released next week now says the mine is scheduled to close in 2011, thanks to an increase in the price and value of coal.

Genwal Resources operates the mine. It is owned by UtahAmerican Energy, which is owned by Murray Energy Corp. The company has not disclosed its plans for the mine.

At its peak, the UGS said, the Crandall Canyon Mine was a huge operation, mining as much as 3.5 million tons of coal per year. State officials now say the mine has gone from "longwall mining," to "room and pillar mining," which does not harvest as much coal as fast.

"They're just cleaning up the remaining resources in that area," Tabet said.

The UGS 2006 coal production report said the Crandall Canyon Mine had produced about 613,000 short tons of coal and was projected to mine about 625,000 short tons in 2007. Genwal Resources estimated its reserves at nearly 11.3 million tons of coal.

The report shows fluctuating employment figures for the Crandall Canyon Mine. In 2006, 154 people were working there. Now, the company has said, it has 71.

A job in a mine is one of the highest paying jobs in the area. Latest Utah Department of Workforce Services figures showed Emery County mines employed 853 people with an average annual wage of $58,826 and a total payroll of nearly $50.2 million. In Carbon County, 894 people work in mining and make an average of $71,794 a year.