The cart's rapid descent - heading 600 feet below the surface - is reminiscent of the falling uranium prices of the 1980s. That particular fall left the Intermountain West's uranium industry in shambles.

Deeper and deeper below the tiny town of La Sal rest tons of unprocessed uranium ore, now too valuable for companies to pass up any longer, said Harold Roberts of Canadian-based Denison Mines Corp., which reopened the Pandora Mine within the last year.

Soon, beams from a few headlamps dance in the darkness ahead. A handful of miners drill into solid rock, emitting sounds that may herald a new Utah uranium boom, one that may be sustained if the world embraces nuclear power as a way to fight global warming.

This latest trend is tied to skyrocketing uranium prices - about $140 a pound, up from about $10 in 2000. The increase is largely due to supply-and-demand issues for an expensive-to-process mineral available only in limited regions worldwide.

For a time, Russia was dismantling nuclear bombs, reprocessing the high-grade uranium for weapons into low-grade uranium for power plants, which may have helped drive down costs, said Ken Krahulec, metals geologist for the Utah Geological Survey.

Also affecting recent supplies: One of the biggest mines in Canada, the world's leading supplier of uranium, is closed due to flooding.

Another factor adding to this record pricing is that a group of private investors is buying uranium and betting prices rise even higher, he said. Plans for China and India to ramp up their nuclear capacity may also be playing into the recent price hike.

"They're going nuclear big time," said Peter Farmer, president of Denison Mines.

All of these factors could simply be a prelude to a major resurgence for nuclear power.

Global warming has forced a renewed debate about how to provide large supplies of electricity in a different way.

Unlike traditional coal-burning plants, nuclear plants emit no greenhouse gases. These gases build in the atmosphere acting to trap heat, which contributes to the planet's warming.

Some hope these arguments will boost nuclear's share of the future energy mix.

For now, mines across the Intermountain West are slowly creaking back to life.

Pandora is one of two operational uranium mines in the state, said Susan White, mining program coordinator for the Utah Department of Natural Resources' Division of Oil, Gas and Mining.

A total of 15 mines have approval to begin operations, while another 10 exploration permits have been granted.

The U.S. ranked 10th in uranium-ore output at 1,692 tons, while Canada led the world with 9,862 tons, according to 2006 figures from the World Nuclear Organization.

If a nuclear renaissance takes hold, places like the Pandora Mine could be active for years to come.

How mining works

In the darkness of the mine on a recent afternoon, the sounds of drills driving into the rock echo through the carved-out passageways. Miners punch holes into the ceiling before sending thin probes into the opening for radiation readings. The data help the miners estimate how much uranium is interspersed with the surrounding rock.

The miners do not need to wear any type of radiation protection, because it takes a ton of uranium ore to yield 6 pounds of uranium. In some Canadian mines, where the uranium concentrations are much higher, robots must be used to remove the ore.

Cowan, who worked the mines during the last uranium boom, is now training the next generation of miners. Safety is among the priorities he stresses to the new crop.

"We haven't had a smashed finger," Cowan said.

Much of the early work has been placing steel support beams on the ceiling to cut down on rocks coming loose.

Other holes being drilled into the walls are for explosives to blast loose the uranium ore. Once they are ready to blast, the miners duck around a corner and brace for the explosion.

Workers maneuver carts into the blast area and use construction equipment to load the broken rocks into a hopper. Every once in a while, a cart barrels out of the mine's entrance.

Workers take radiation readings of the ore and dump the haul into one of several piles that dot the Pandora Mine property.

A series of chemical processes at a uranium milling plant separates the uranium from the ore, and eventually produces what is known as yellowcake uranium. The final product goes to other facilities designed to prepare the uranium for processing into fuel rods, which power nuclear plants, Roberts said.

The mine now runs one shift a day with its 14 employees, Roberts said. As they hire more miners, the company hopes to build up to a second shift.

But finding miners is a challenge.

Most of the miners that fueled Utah's last uranium boom in the 1970s and '80s have moved on to other industries or are no longer in good enough shape to handle the daily rigors of work in the mines, said Cowan.

In addition to recruiting new miners, uranium companies are stealing experts from other industries, like gold and coal mining, Roberts said.

Boom or boomerang?

HEAL Utah, a nonprofit group that monitors nuclear issues, does not welcome the revival of mining and milling operations in Utah.

Taxpayers were left to foot the bill from the previous uranium booms, which included cleaning up dozens of abandoned mine sites. The milling process also leaves polluted tailings that must be dealt with, said Vanessa Pierce, head of HEAL Utah.

The latest cleanup efforts involve almost $100 million from the Department of Energy to remove uranium tailings near Moab.

"We're going to see history repeat itself," she said of cleanup costs.

Radon gas also posed health risks to miners and past workers have filed for federal compensation because of illness linked to mining, Pierce said.

Roberts counters that mine safety is a greater concern today, and ventilation systems are in place to prevent the buildup of dangerous gases, such as radon, which debilitated miners in the 1950s and '60s.

Some towns in southern Utah could be bustling once other mines begin operations. Roberts said these efforts will help improve the regional economy as well as the nuclear industry.

Denison Mines hopes when the Pandora Mine is running at full speed, it can produce about 4,000 tons of uranium ore a month. While a productive total, the company has bigger plans for the Tony M mine near Ticaboo.

"This is going to be a pretty good size for a uranium mine," Roberts said, standing near one of the Tony M mine's two entrances. Each entrance stretches 2 1/2 miles into the side of the cliff face.

When it's fully operational, 150 miners could be pumping out up to 15,000 tons of uranium ore a month.

The influx of ore from both mines will also help another of the company's uranium facilities start running at full bore again.

Denison's White Mesa Mill, near Blanding, is one of four uranium processing mills in the nation. Utah has a second mill, Shootaring Canyon, near Ticaboo, which is owned by sxr Uranium One.

"That'll open things up for the little guys," Roberts said, once the White Mesa Mill starts running.

The mill will set a buying schedule, which is expected to encourage the smaller "mom and pop" mining operations to start up, he said.

If Utah is at the leading edge of the next uranium boom, a worldwide expansion of nuclear power could make the ride last longer than usual.

glavine@sltrib.com