Identification and Ranking of Noise Sources on a Jumbo Drill Machine During Operation

Abstract

Noise-induced hearing loss (NIHL) is the second most prevalent illness in the mining industry. According to a study conducted by the National Institute for Occupational Safety and Health (NIOSH), in which over 42,000 audiograms from metal/nonmetal miners were analyzed, approximately 70% of miners have hearing impairment as compared to 9% of non-occupationally noise-exposed workers. One of the machines used extensively in metal/nonmetal mines responsible for high noise exposure levels of its operators is the jumbo drill, used to drill holes at the mines for blasting purposes. In this context, NIOSH is conducting research to develop engineering noise controls for jumbo drills that would reduce the prevalence of hearing loss among operators of this equipment. The first step of the noise control development process consists of identifying and ranking dominant noise sources present during operation of the jumbo drill. To this end, a noise study was conducted at NIOSH’s laboratories in which a microphone phased array system was used to identify dominant noise sources, and the transfer path analysis method was used to rank these sources based on their contribution to the operator location. Results showed that the drill string and the drilling mechanism — known as the drifter — are the dominant sound-radiating components in the operation of the jumbo drill.