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HUNTINGTON, Utah (Reuters) - Six miners were trapped in the collapse of a coal mine in central Utah on Monday and experts said initial reports of an earthquake might have been the rumbling from the mine's cave-in.

No contact had been made with the miners some 12 hours after the collapse. But the mine operator said rescue teams had come within 1,700 feet of the trapped miners and work was being done to drill from the top and horizontally.

"You have six miners who all could very well be alive," Utah Gov. Jon Hunstman told Reuters outside the Crandall Canyon Mine, 140 miles south of Salt Lake City.

"In fact, the experts tell us that they are and the rescue attempts are increasingly close to the cavern where they think they are located."

Robert Murray, president of Murray Energy, which owns the mine operator, told reporters he was certain of the location, but did not know the conditions surrounding the miners.

"They could be in a chamber that is 1,000 feet long or they could be dead," Murray said, adding that "time is of the essence."

Some 200 employees and four rescue teams were at work, he said. A helicopter was drilling from the top of the mine located in a steep, craggy canyon.

The U.S. Geological Survey reported a 4.0 earthquake on Monday morning at 2:48 a.m. (0848 GMT), about 16 miles northwest of Huntington and at the relatively shallow depth of five miles.

A quake of magnitude 4.0 is capable of causing moderate damage and it was initially believed the nearby mine collapsed after the seismic movement.

ANALYZING SEISMIC ACTIVITY

But the USGS National Earthquake Information Center said it was analyzing data to determine whether the shaking was produced by the collapse, which occurred around the same time.

"If you have a mine collapse, there will be a seismic component," Harley Benz of the NEIC told Reuters.

"We simply don't know at this point," he added, noting that the analysis could take up to 48 hours and perhaps longer.

Gov. Huntsman said he would meet with the miners' families at an undisclosed location. "Hope is in order at this point. Heavy doses of hope," he said.

The area in central Utah is known for its mining industry and has seen its share of tragedy. A fire at the nearby Wilberg mine killed 27 people in 1984.

"All we can do is wait and pray and let the rescuers do their job and until we hear, we will continue praying with the families of the missing miners," said Brad King, a Utah state representative from nearby Carbon County.

Concerns about mine safety in the United States resurfaced last year when 12 miners were killed in an explosion at International Coal Group's Sago mine in West Virginia.

In response, Congress passed the Mine Improvement and New Emergency Response Act, which President George W. Bush signed into law last year.

(Additional reporting by Steve James in New York and Mary Milliken in Los Angeles)