Abstract
The Bureau of Mines has developed the shearer-clearer--a new type of dust control system for longwall shearers. The system partitions the airflow around the shearer into a clean split and contaminated split. The dust cloud is confined to the vicinity of the coal face, while the shearer operators remain in the clean split on the gob side of the machine. The shearer-clearer operates on the principle that each water spray moves air like a small fan and can be positioned to direct the duty air towards the face. The hardware is inexpensive and can be installed in a single shift. It consists of several strategically mounted water sprays and one or more passive barriers. Laboratory testing indicates reductions in shearer operator dust exposure as high as 97 pct. Preliminary results from an underground demonstration in one mine also indicate that considerable dust reductions at the shearer may be obtained. In conjunction with the development of the shearer-clearer, dust surveys were conducted in three other mines to determine if some shearer spray systems currently in use partition the flow in a manner similar to the shearer-clearer, and if so, whether this partially accounts for markedly cleaner conditions on some longwalls. Results from these surveys indicate this to be the case.
