Coal Age

OCT 2015

Coal Age Magazine - For more than 100 years, Coal Age has been the magazine that readers can trust for guidance and insight on this important industry.

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On December 7, 2014, Raisebor, a division of Cowin & Co., completed a 26-ft-diame- ter raise bore shaft to a depth of 1,440 ft, the largest diameter raise bore ever in North America, and appears to be the largest in the world. Raisebor performed the record-setting feat at the Jim Walter Resources No. 7 mine near Brookwood, Alabama, using an Atlas Copco Robbins 123R C raise boring machine and multi- modular wing system (MMWS) reamer. The reamer was designed for this job in a collaborative effort with Atlas Copco design engineers. The project started in 2009 when Rick Sidwell, general manager of Raisebor, started thinking about a larger raise bore. He knew the drill for this job needed to be special. "I see the industry going this way. It's a safety factor that just makes sense," Sidwell said. Years of planning and engi- neering followed. The mine was sinking this shaft to offer miner and utility access closer to the work- ing face. It was taking workers roughly an hour to reach the working face. Nearly 25% of each 8-hour shift was lost to commut- ing. The shaft was needed to make the mine more efficient. The 1,440-ft-long, 26-ft-diameter raise was actually the third project for the com- pany's Atlas Copco Robbins 123RH C raise boring machine. Two earlier, 20-ft raises were just enough for the crew to stretch its legs and get ready for the big pull. 18 www.coalage.com October 2015 Hard rock miners commonly bore raises between levels underground, and now Raisebor, a division of Cowen & Co., has successfully used the technique to develop a shaft at a deep coal-mining operation in Alabama. Above: the Raisebor team in the foreground, the raise boring drill in the background. r a i s e b o r i n g The reamer was assembled on the surface custom to Raisebor's specification, disassembled, taken under- ground and reassembled. Inset: Atlas Copco Secoroc cutters for the raise bore reamer. A new Approach to Shaft Development Work Raisebor engineers the largest diameter raise in the Alabama coalfields

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