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gateroad development Faster Roadway Development Slower cutting speeds increase safety and reliability throughout the entire operation BY KIRBY OWEN AND THOMAS VALLANT and Russia. A total of 300 bolter miners have been delivered since inception and most are employed in longwall roadway development. They can also be used for room-and-pillar mining in soft rock operations such as salt mines and potash mines. The MB 600 includes various models with different operating heights ranging from 7.5 to 14.5 ft. The U.S. predominantly uses the MB 450 and new MB 610. The MB 670 is popular in Canada. The Operations Sequence The latest addition to Sandvik's Bolter Miner family is the MB 610. More than 20 years ago, Sandvik introduced the bolter miner to the coal mining industry with the first machine at Australia's Tahmoor Colliery. The bolter miner concept quickly spread to other coal mining countries. Over time, with input from many longwall mines interested in improving advance rates, the machines continued to evolve. The latest addition to Sandvik's Bolter Miner family is the MB 610. With improved safety features and ergonomics, it was designed to increase productivity. In addition to flexible roof-bolting techniques, this bolter miner has demonstrated an improved life span for components. It is capable of cutting through hard intrusions as well. The MB 610's unique slow-cutting speed provides high-cutting forces, resulting in an increased cutting rate and reduced dust creation. Two of these machines are currently proving their worth at CONSOL Energy's Bailey complex, which is one of five U.S. longwall mines operating two longwall faces. Working with the first machine, the 30 www.coalage.com development teams at the Bailey mine have advanced more than 56,000 ft, with an average shift advance of more than 120 ft during 2012. One of the most important factors for longwall mining is panel development. The longwall panels must be mined before the active face reaches the stop line. With development, time is money. Many efforts have been made to increase development speed and improve safety. This article aims to show how hard rock cutting principles can be applied to longwall mining to improve performance and safety. Introducing the Concept The first Sandvik Bolter Miner was introduced to the Australian coal industry in the early 1990s. At the time, the machine was known as the ABM 20, which was designed and built by the Austrian company, Voest Alpine Bergtechnik, which was later acquired by Sandvik in the late 1990s. The machine showed its potential and it soon spread to other countries, including South Africa, the U.S., China A bolter miner combines a roof- and ribdrilling machine and a continuous miner. It drills and bolts while it cuts and conveys coal to the rear of the machine. The key feature is the sliding frame, which allows simultaneous mining and bolting. The sliding frame carries the cutter-head and allows a longitudinal travel of 39 in. to 55 in., depending on the machine model, relative to the machine body, which carries the support and bolting units. The MB 610 trams on crawler pads and it uses hydraulic power to sump the sliding frame. As many as four roof-bolting rigs and two rib-bolting rigs can be integrated on the machine's main frame. A typical operating cycle begins by tramming the machine up to the face and putting it into the cutting position. Two to four stab jacks are lowered to the mine floor and an automated temporary roof support (ATRS) canopy is set against the roof. This guarantees a high level of safety for the roof bolters, who are working under the temporary roof. The operating cycle continues with the bolting mode being engaged. The bolters start their activities. The cutter boom is raised and the loading apron is moved forward. They load the material toward the end of the machine. The steps of the machine's operation cycle are repetitive, which improves safety and reduces operational delays. September 2013