Remote Control Jackleg Drills Reduce Operators’ Overall Noise Exposures Available to Purchase

Jackleg drills have proven to be a problem when it comes to overexposures to noise for coal miners as well as metal/nonmetal miners. These pneumatic drills are used to drill holes for roof bolting or blast holes in developmental and stoper mining. They are used when mining vertically or steeply inclined deposits. The “Leg” is a heavy metal support which allows the driller to keep the rig steady when collaring the hole as well as keeping it steady while drilling into the hard rock. Since drilling is done basically by hand, the operator remains in close proximity to the noise associated with the pneumatic hammer. Up until now, little has been done with the exception of Original Equipment Manufacturer (OEM) and retrofit mufflers to achieve compliance with the noise standards stated in Code of Federal Regulations (CFR) Title 30, part 62 for the drills of the type. Just recently an anthracite coal mining company, having noise problems associated with their jackleg drills, purchased a “Remote In-Stope Drill Rig” from a manufacturer in South Africa. A noise study was conducted by the Mine Safety & Health Administration (MSHA) and the cooperative mining company to determine the effectiveness of the remote control jackleg drill in reducing the operator’s overall noise exposure. The baseline test was conducted on the original jackleg drill. Once the new remote unit was received, it was tested as received from the manufacturer with their hammer and again with the company’s original hammer retrofitted to the drill rig. The company also made modifications to the 8 ft. hose extending it to 20 ft. to allow operation further from the noise source. The study was conducted to determine the effectiveness of the remote control unit in reducing not only the sound level, but also the overall noise dose. The unit was found to not only reduce the operator’s overall noise exposure when used with either hammer, but allowed drilling to be conducted from a location under permanently supported roof with no vibration on the operator’s hands.