The familiar sound of a diesel engine filled the air, as the truck bounced its way into the tunnel. With every bounce, the truck made its way deeper into the mine its final destination still more than three miles away.
The truck had to make its way 1,000 ft. below the earth's surface before there was reason for it to stop. For miners at the Twentymile Coal Company in northwest Colorado, the drive is a daily ritual.
Twentymile officials invited people from Moffat and Routt counties to tour the mine. Four people participated Thursday. They were given safety instructions, decked out in protective gear, and taken underground.
Twentymile has made quick progress since it began production in 1983, setting new standards and establishing new world records in the coal mining industry.
"We get people coming to visit the mine from all over the world," said Ron Spangler, human resources director for Twentymile Coal Company. "People continue to come here and see how it is that we can continue to work in such a efficient way. We have developed a system that allows us to retrieve as much coal as possible without overextending ourselves financially."
From mid-1985 through Dec. 31, 2000, Twentymile Mine has produced more than 62,968,933 tons of clean coal. Clean coal is described as coal that is free of rocks and needs little refinement.
The mine boasts more than 8.5 miles of conveyor belt in the underground portion of the mine, which extends more than two miles on the surface, and can carry more than 58,560 tons of coal a day.
"Our people who work here are extremely proud of what they do," Spangler said. "It's no longer the pick-and-axe days that people tend to think of when they think of a coal miner."
Gone are the days of the rail car that transported miners into the mines. Now, miners travel by trucks powered with diesel fuel regular gasoline could create a spark, and all kinds of trouble for those underground.
"We are very conscious here about what we do safety-wise," said Dianna Ponikvar, safety representative for mine. "Of course, from time to time you are going to have incidents, but that is just one of the occupational hazards of working in a mine.
"Cut fingers, back problems, and other minor injuries are what we see mostly. Once in a while, though, we do have the stereotypical, serious coal mine injuries, most of which come when the ribs peel off the mine walls."
Ribs are slabs of coal that protrude from the mine wall on the main travelways and work areas. Although most of the ribs are secured with a wire mesh support, it is not uncommon for those to give way.
"Most of the serious accidents that we see in the mine are the result of people walking too close to the ribs and having them break away," Ponikvar said. "They don't look as though they would weigh that much, but if you get a four foot slab that peels off and falls on you, there is going to be trouble."
The ribs look similar to flat, stalactites and stalacmites that occur in underground caves. Because of this, miners and visitors are instructed to stay as close to the middle of travelways when they go to and from the work areas.
The mine's main production comes from a technique known as longwall mining. Twentymile's current longwall is more than 1,000 ft. wide and more than 2 miles long.
Miners operate a remote shearer that travels at a rate of 140 feet per minute, cutting 36 inches of coal away from the longwall, and dropping it onto the conveyor.
Each shift removes a 60-foot section of the longwall, producing an average of 22,000 tons of coal each shift. On the average, the direct cost to consumers is about $20 a ton.
With more than 55 percent of the U.S. energy being supplied by coal, many people are surprised that coal is the main reason that U.S. electric rates remain the lowest in the world.
"Here at Twentymile Mine, we produce over a third of the coal that comes out of Colorado," said Mike Ludlow, general manager for the Twentymile Mine. "Our customers range as far east as Western Kentucky and as far south as Mexico. We supply Colorado Springs with coal for their electric plants and are the main supplier to Denver Public Service.
"One of our good customers is located in Rock Springs, Idaho," he said. "That is where they make Round-Up herbicide, and yes, coal is intricate part in that process. People would be amazed by some of things that coal can do."
Twentymile Mine has 12 to 13 years left on its government permit, allowing for recovery in the current longwall to continue. They will then apply for another permit that will open new areas of the mine property to mining.
"The coal reserves that we have here are very large," said Ludlow. "We have more than 110 million tons, with an average depth of 1,300 ft. We are also proud to have one of the cleanest coal productions in the world, along with some of the best workers."