Coal mining is one of the most dangerous occupations in the world. Nearly 6,000 Chinese miners were killed in accidents last year, prompting Beijing to begin closing some 5,000 unsafe mines. The U.S. Congress is considering new safety legislation in the wake of the fatal accidents in January at two coalmines in West Virginia.

Operators of silver, gold, and zinc mines in the Pacific Northwest claim they have a safety record to be proud of.

The Pend Oreille zinc mine is near Metaline Falls in remote northeastern Washington State. About 90 miners work underground here, digging ore at the bottom of a slanting eight kilometer long tunnel. Federal regulations require metal mines like this one to do an all-day rescue drill every two months. This is the first one since the January mine disasters in West Virginia.

Safety and training superintendent Al Stuart lays out the day's drill. "Well, what we have is a simulated injury situation where two fellows were working up on our conveyor gallery. One of them fell." He follows the mine's yellow fire truck down the twisting main tunnel to a junction about 150 meters under rock. Mine rescue team members gathered there strap on breathing masks and grab a stretcher.

"The key with these people is to give them enough confidence with the breathing apparatus that they're not afraid of it," Stuart explains, "that they know that it's going to work, that the tools that they're using (are) going to work. That way, when they're in, trying to rescue somebody, they're not worrying about all the little things about themselves."

Hardrock miners face lower risk from explosion than do coal miners. "In coal mining there are more things that burn," says Pend Oreille Mine's general manager, Mark Brown. "The coal, dust itself, the methane, are bigger hazards than we have to deal with."

That said, fire remains a major concern. So this day, a smoke bomb simulates the fumes that overcome the pretend victims lying in the darkness ahead. "They created a bit of a fire when they were burning and welding," Stuart says, as the rescue team leader shouts commands, "so we have some gases in the area, and some smoke in the area."

In a real emergency, miners underground could retreat to airtight refuge chambers. All of the big mines in the Pacific Northwest have sealable rooms, stocked with compressed air. It's a place to stay alive while rescuers marshal. Most also have secondary escape tunnels. And unlike in West Virginia, they all have mine rescue teams on-site.

The searchers press ahead and soon find 41-year-old miner Wayne Mankins. He's pretending he collapsed beneath a telephone box after calling for help.

"You a little sick, buddy?" asks one of the rescuers. "Sick. My head hurts?" he mumbles.

Mankins is usually on the other side, serving with the volunteer fire department, county search-and-rescue and the mine rescue team. "I've got two of my own kids that work here at this mine," he says later. "I like to know that in case of emergency with my family, with the people I work with, or just out in general, that I've got knowledge."

The recent safety record for underground mines in the Northwest is fairly good. Local mine union president Rex Auger feels the current mine safety rules are generally adequate. "You try to think of the worst and you try to cover for that. And there's always something different that does happen you can't foresee. They keep up on it pretty good."

Still, across the country, lawmakers are calling for tougher safety enforcement and better emergency equipment. Pend Oreille Mine manager Mark Brown agrees that there's always room for improvement, but warns that mandating technology is tricky. "Mother Nature never made two ore bodies or two mines the same," he points out. "So technologies that work in one mine, don't necessarily work in another. If you have a very conductive mine, some methods of communications work well? where in other mines they don't work at all. So it's hard to do a broad brush."

Meanwhile, the Pend Oreille Mine rescue team has threaded its way around a conveyor belt and sprinkler system with the second "victim." They make it to fresh air by their fire truck. Safety Superintendent Al Stuart declares the drill successful, telling the team, "I'm proud of you. You did a really good job today, you did."

The rescuers hit the showers. And then it's on to a debriefing. Tomorrow, the six go back to their regular work, digging zinc out of the mountain.