Modified shearer clearer system for dust and methane control

The shearer clearer system was designed, tested, and proven to be effective at lowering shearer operator dust exposures during the mid-80`s by the US Bureau of Mines. This technique uses a series of water sprays positioned on the shearer body and splitter-arms. These water sprays not only knock down a portion of the dust cloud generated during cutting but also act as small fans that move a substantial amount of air and keep the dust cloud from dispersing over the shearer body and contaminating the operators. At a number of operations, shearer operator respirable dust exposure levels have been lowered approximately 50 to 60 pct using this technique. Because of the air moving capabilities of this technique, the Bureau of Mines believed that a modified version could also be effective to lower methane levels around the shearer, thus reducing the likelihood of a shearer-generated methane ignition. Two additional spray blocks were added to the system to provide for improved air movement around both cutting drums. A laboratory study performed with the modified version in a full-scale longwall gallery resulted in a 73 pct reduction in methane concentrations at the shearer machine for both cut directions. There have been a numbermore » of longwalls that have implemented modified shearer clearer systems over the past few years. Although there has been no detailed field analysis on these systems to statistically provide a percent reduction in methane levels on the machine using the technique, all indications are that the system is effective for both dust and methane control. The air moving capabilities of the system provide more turbulence at the cutting drums and reduce methane levels. The intent of this report is to provide a detailed description of the modified shearer clearer system. Engineering drawings are provided for all major components of this system to assist operators who may be interested in installing it at their operation.« less