New roof support offers boost to mining industry

A safe, simple roof support developed at SIUC for the mining industry should be on the market within the next few months.

Prop-er respect -- Using a hydraulic lift, E. Bane Kroeger tests his mine roof prop at the Coal Research Center. Kroeger, an assistant professor of mining and mineral resources engineering, says his invention begins supporting the roof while it's still being installed.

Excel Mining Systems Inc. will manufacture the K Prop, named for its inventor, Assistant Professor of Mining and Mineral Resources Engineering E. Bane Kroeger. The 14-year-old company, headquartered in Bowerston, Ohio, sells roof systems to coal and hard rock mining companies throughout the country.

"We have a full product line but don't presently have a roof prop," said Excel President and CEO Bruce A. Cassidy Sr.

"We liked the design -- being able to put some active load on the roof at installation. It's one of the few props that has that capability."

The K Prop consists of two steel pipes, each with a flat plate at one end. The pipes telescope together, allowing the prop to adjust to fit roofs of varying heights. There's also a steel collar, which clamps down at the point where the two pipes join.

It's that collar and some machine work around the pipes' connecting edges that account for the prop's near-instant ability to support a roof as it's being jacked into place.

The K prop can support loads from 10,000 to 100,000 pounds. A miner working alone can install one in less than two minutes.

"That should reduce the total cost of supplemental support installation by a significant amount because up to 60 percent of the costs in a mine are from labor," Kroeger said.

Excel's Cassidy also expects to see savings up front.

"This prop replaces wooden props, and as hardwoods are becoming more scarce, the price is going up," he said.

In addition, when miners build timber cribbing (heavy wooden support posts stacked to the mine roof like Lincoln Logs) in certain areas of the mine, they can suffer lower back injuries.

"From a safety standpoint, there's much less chance of injury (with the K prop)," Cassidy said.

Safety is also a concern with other steel props on the market, Kroeger said, because most use bolts that require a specific amount of tightening to support the roof.

"If these things aren't installed to the manufacturers' specifications, the roof could come down," he said.

Kroeger said the idea for his K prop came during a class lecture on an existing support system that couldn't bear the weight of a roof until workers had finished tightening the bolts.

Working on his own after hours in an SIUC machine shop with scrap pipe that he bought at a junkyard, Kroeger designed, tested and refined scores of roof supports in developing the K prop.

"It's been fun," he said. "Of all the things I do at SIU this is what I enjoy most -- coming up with new ideas, building them and actually doing the testing."

– K.C. Jaehnig