| Production and safety have always been a prime issue for mining industry and mining engineers, who strive hard to achieve the critical balance between them. Hearing loss and uneasy working environment are few common ones affecting the health statistics of a underground mine. As a result, recent years there have been the focus on to develop an engineering controls to reduce the underground noise. Unique work has been done in this thesis to add additional information on the active noise control technology applied to Longwall mining operations.; Mostly, the survey results indicated that the frequency content of each noise and the number of events decide on the effect on worker. Also, in Stage loader the Lower frequencies showed a significant contribution to the overall sound pressure level (SPL). However, under some combinations the contribution of higher frequencies cannot be denied. Based on these findings, Active Noise Control (ANC) set-up was prepared for canceling the unwanted frequencies and reduces the overall sound pressure level. It was also found that the ANC was more effective for the lower frequencies ranging from 100 Hz to 700 Hz and cancellations were more significant for the low frequencies than for the higher ones. (Abstract shortened by UMI.)... |
