A control suite to reduce roof bolting machine drilling noise.

Abstract

Among underground coal miners, hearing loss remains one of the most common occupational illnesses. In response, the National Institute for Occupational Safety and Health (NIOSH) conducts research to reduce the noise emission of various underground coal mining equipment, an example of which is a roof bolting machine. Field studies support the premise that, on average, drilling noise is the loudest noise that a roof bolting machine operator would be exposed to and contributes significantly to the operators’ noise exposure. NIOSH has determined that the drill steel radiates a significant amount of noise during drilling. NIOSH in collaboration with Corry Rubber Corporation has developed a suite of controls to reduce drilling noise which consists of a bit isolator, chuck isolator, and a Collabsible Drill Steel Enclosure. This control suite effectively reduces the noise radiated by the drill steel. Laboratory testing confirms that the control suite reduces sound pressure levels generated during drilling by 13 dB(A) at the operator’s location. As a result of this reduction in drilling noise, the noise exposure of the roof bolting machine operator is reduced.