Weighty Issues Mining Accidents Have Industry Looking At Ways To Lighten Jackleg Drill

Fifty years ago, jackleg drills revolutionized mining in Idaho’s Silver Valley by providing a powerful, hand-held tool that a single miner could operate.

Now, researchers are looking for ways to revolutionize the 120-pound jackleg. They want to lighten it.

Robert McKibbin, an engineer at the Spokane Research Laboratory, tracked mining accidents related to jacklegs over a five-year period.

“They all boiled down to one thing. It weighs too much,” said McKibbin, whose organization is part of the National Institute for Occupational Safety and Health.

At the Lucky Friday Mine in Mullan, Idaho, new hires lug a jackleg drill up a flight of stairs. It’s part of a fitness test that demonstrates their ability to work underground.

“It takes a pretty fit and skilled person to operate a jackleg without getting hurt,” said Clyde Peppin, the mine’s chief engineer.

Rates of back injuries at the mine dropped three years ago, when jumbos went into use. On jumbos, drills are mounted on a boom and don’t have to be held or moved by hand. But the 14-foot long machines can’t take the place of jacklegs in small places, Peppin said.

The Lucky Friday’s 53 jacklegs get such constant use that he replaces about a dozen each year. McKibbin’s challenge is to lighten the jacklegs without sacrificing power.

An “83” is the standard model used in the Silver Valley. The drill itself is 80 pounds of steel honed to deliver up to 2,400 blows per minute. The leg and the hoses add an additional 40 pounds.

“They’re heavy, noisy and powerful, as powerful as a hand-held tool as you’re going to find,” McKibbin said.

Researchers at the Spokane lab took 20 pounds off the drill by enclosing its internal parts in an aluminum-titanium case instead of steel.

They’ve begun testing the lighter drill’s performance on cement blocks. Later, they’ll take it to the Lucky Friday to have contract miners test it.

“They’ll be able to tell in short order whether it’s something that they’d use,” McKibbin said.

Adding titanium will increase the cost of jacklegs, which already run about $4,000 apiece. There are also questions about how the titanium-aluminum case will hold up to constant battering, and whether the lighter-model will drill as quickly through the valley’s tough, quartzite rock.

Efficiency is critical for contract miners, whose paycheck depends on how much rock they move. Midwestern Machinery Co. of Joplin, Mo., has manufactured jackleg drills for 20 years. It also built the prototype for McKibbin.

“Weight is a big issue,” acknowledged Dale Rodman, vice president of sales. But he isn’t convinced that the industry is ready to embrace a lighter jackleg.

Company discussions about design changes over the years have resulted in the same response from the mining industry, he said.

“They unanimously said, `Don’t touch it,”’ Rodman said.

“The miners will say, `Real miners use an 83.”’

See related story under the headline: Special technique is needed to tame a jackleg