GILLETTE (AP) - Meet Lee Yake.

He has 25 years of experience working in Powder River Basin coal mines.

A couple of years ago, he decided he'd had enough of the long hours and that it was time to retire. At 59, he is his own boss after buying Industrial Alternators and Starters. If offered him a good change of pace, and provides him with a business he plans eventually to turn over to his son, Terry.

Standing in front of shelves filled with rebuilt starters and alternators for every size of vehicle from pickups to 300-ton haul trucks, Yake said many of his friends who began working in the mines during the 1970s are also considering retirement.

"There's a lot of people that started back when I did that aren't in the Social Security range," he said. "Most of the guys I've seen around, they've had enough."

When they leave, they will take with them a wealth of knowledge.

Meet Dave McElhiney.

The 46-year-old former sheriff's deputy has been working as a mechanic for Powder River Coal's Caballo mine for the past four years. That's long enough to know that more than one of his co-workers is eying retirement.

"I got one that's retiring in March, one that's retiring at the end of the year and a bunch that are retiring in three to five years," he said.

He worries that when people like Yake begin to clock out for the last time, they will take with them critical knowledge. For example, not many new hires can modify older machinery and bring it up to code.

"Once that knowledge is gone, it won't be able to be replaced," he said. "It's a common knowledge of what they know, there's not a teaching manual."

Those retirements also will contribute to what has become a critical work force shortage in this area.

Many of the employees who began working at area coal mines when oil companies first built them three decades ago are now approaching retirement age, said Marion Loomis, director of the Wyoming Mining Association.

"We were bringing in a lot younger people in those days," he said. "Those employees … are nearing retirement rapidly."

When those people begin to leave, it will make replacing skilled workers such as welders, diesel mechanics and electricians more difficult than it is now, he said.

"I know that the need for employees is a very big one," Loomis said. "As our work force ages, we're going to see a lot of retirements exacerbate that problem a great deal."

State and federal figures show a wave of retirements on the horizon.

A Bureau of Land Management report to be released this spring shows that a majority of miners in the Powder River Basin are older than 45.

And while Wyoming workers on the whole are younger than their national counterparts, Department of Employment statistics show that 35 percent of workers in mining, natural gas and oil industries were older than 45 in 2003, up from 26 percent in 1994.

It's an issue that Gov. Dave Freudenthal and Powder River Coal President Kemal Williamson both used to support separate initiatives for job training at Sheridan College's Gillette Campus.

"Many new workers are needed in Campbell County just to maintain our current level of energy production," Williamson wrote in a July letter supporting a Department of Labor job training grant. "The current work force has a disproportionately large number of workers reaching retirement age."

Freudenthal told The News-Record in January that as workers who came to Wyoming with the original energy booms retire, the face of workers will change across the state.

"We're looking at a pretty immense transition in the energy work force," he said.

Retired coal miner Don Haney said there is a cost, both in time and money, when experienced and loyal workers retire. But he is among those who don't believe the coming retirements will have a huge impact on the mines.

"There is an impact to the companies to lose an experienced employee," said Haney, 64, who retired from Belle Ayr mine as a safety director after working there for three decades. "I don't know that it would be that big of a deal because people aren't leaving all at once."

Officials at Campbell County-area coal mines say they are more concerned with the broader issue of worker shortages than with the imminent retirement of baby boomer miners now in their 40s and 50s.

Fewer than 10 percent of employees at Arch Coal's Black Thunder mine however - the largest producing mine in the world - qualify for retirement this year.

"We don't expect a bubble of retirements," Greg Schaefer said.

He and officials from Kennecott Energy and Peabody Energy - three coal producers that together employ more than 3,500 people and mine almost 320 million tons a year - all say that retirement is not a pressing issue for their companies.

"Our need for employees in the future is driven as much by projected growth as by projected attrition by retirement," said Ryan Tew, human resource manager for Powder River Coal, a Peabody subsidiary.

"We will have to replace retirees, but we're more concerned about getting the workers we need."

The tight labor market has forced the company to hire inexperienced workers to meet its goal of hiring 100 new people every year at its three local mines, Tew said. Peabody is building a training center at Rawhide mine to help employees maintain their skills. It will be one of three centers across the nation.

Schaefer also pointed to growth rather than retirement as the impetus for more aggressive hiring strategies.

"The skilled positions are in high demand, very high demand. And just with the worker shortage in the western United States, the people that work hard and show up on time are in high demand," he said. "You've got to go looking."

In addition to a regular regimen of local advertising, Arch has turned to Texas, Colorado, Washington and Oregon - markets they have never tapped before. Peabody, meanwhile, has advertised some jobs on the Internet, attended military job fairs and participated in local single-family hiring programs.

Tew said those efforts have been met with limited success and that Peabody is focusing its efforts on hiring locally through its training center.

"We are trying things we haven't tried before," he said.

Powder River Coal has maintained a steady hiring rate since it entered the basin in the 1980s. Because of that, the company's work force is diverse in age.

As a result, Powder River Coal expects on a 2 percent to 3 percent retirement rate over the next five years, Tew said.

Schaefer described a different picture of how mines in Campbell County have hired over the past three decades - a stop-and-go process that has resulted in what he calls "two distinct work forces."

"If you look 10 years ago, when prices were in the toilet, the mines didn't do a lot of hiring," he said. "It was pretty flat employment."

Once hiring picked up, younger people began getting mine jobs.

Troy Chodrick, a sales manager for Houston-based engineering firm T.F. Hudgins Inc., said it has created a big gap.

But the industry, and businesses that support it, will retain some of the retirees' knowledge and experience when they become consultants or work in related fields, said Chodrick, 39.

"Those guys are going to end up supposedly retiring, but they're going to come back in consulting roles," Chodrick said during a trade show in Gillette this fall.