Aspects of Noise Generation and Hearing Protection in Underground Coal Mines.

摘要

The objective of the study was to identify quantitavely the spectral and amplitude characteristics of coal mine warning signals and assess the feasibility of using personal ear protection to minimize noise exposure but not impair a miner's safety. Roof warning signals from 11underground coal mines,principally in the Pittsburgh seam,were studied and analyzed. The character of individual acoustic warning signals is shown to be dependent on spectral distribution of energy. Reverberation times (pulse decay rates) were found to be usually between 0.1and 0.5seconds. Listening tests were conducted to assess the miner's ability to discriminate speech and roof talk signals in noise and in quiet,with and without ear protectors and with various levels of hearing loss. The ability to detect roof talk is shown to be generally degraded while wearing ear protection in quiet,although,if ear protectors are worn only when required by high noise levels,the ability to detect roof talk will be preserved at its maximum. (Author)