NTIS: PB/246-381 Available for Reference At Bureau Libraries :153 pages
This report describes the results of a research program to develop methods of controlling both the exhaust-air noise and the mechanical noise of a stoper drill used for roof bolting operations in coal mines. Several systems have been designed and tested that reduce the noise level to the low 90-dba range. These systems employ a muffler for exhaust noise, an acoustic barrier for the mechanical noise radiating from the drill body, and either absorptive foam or a damped sheath added to the drill rod to reduce its ringing.
CP; Final Contract Report;
NTIS Accession No.
NTIS: PB/246-381 Available for Reference At Bureau Libraries
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