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Noise Source Identification Project Draglines, Shovels & Air Arc Cutting. Team Members Richard Gates, Assistant District Manager - District 9 Bob Cornett Michael S. Horbatko Michael L. Lynham Robert Smith Peter Saint. Noise Source Identification Project Draglines. Background Information
Richard Gates, Assistant District Manager - District 9
Michael S. Horbatko
Michael L. Lynham
MSHA has conducted noise surveys on over 220 operators/oilers. Although the sound pressure levels ranged from 96 dBA to 112 dBA, only 12.5% had exposures above the PEL.
Oilers are required to perform various tasks in the dragline house.
The time required to perform these tasks varies from day to day. It ranges from 30 minutes to greater than 2 hours.
A meeting pertaining to “Achieving MSHA Noise Standards on Draglines” was held in December, 2000 at Milwaukee, WI. The meeting was sponsored by Bucyrus International. It was attended by MSHA/NOISH, mine operators, dragline manufacturers, and noise abatement consultants.
The purpose of the meeting was to share:
1. Information what steps have been taken to comply with MSHA’s noise standard.
2. Information on current noise control methods and,
3. Strategies on achieving compliance with MSHA’s noise standards.
Currently, the most effective means of controlling exposure to noise is to use administrative controls to limit the amount of time spent in the dragline machine house.
Remote monitoring using cameras can be used to reduce the time necessary for dragline operators/oilers in the dragline house.
P & H Mining Company is developing methods for quieting motor cooling fans in the machine house of their shovels.
Air arc cutting is used to cut dragline or shovel buckets to remove defective parts or to gouge out cracks found in the frames of draglines or buckets. A copperclad, carbon rod is used to create an arc that generates enough heat to melt the metal. Compressed air is used to remove the molten metal from the cut. The noise is generated when the air disturbs the magnetic field created by the arc which results in a loud crackling sound. The sound pressure level ranges from 108 to 120 dBA.
A welder’s personal noise exposure depends on the amount of time spend gouging during their work shift. The highest dose obtained during this study was 483 percent for 10 hour shift.
360 Amps - 116 dBA Average
Electra Rod - Rockmount Research & Alloys, Inc.
Hypertherm - Plasma - Hypertherm, Inc.
Magnum Rod - Magnum Manufacturing, Inc.
Cronatron Rod - Cronatron Welding System, Inc.
Certanium Rod - CT Engineering
Petrogen - Petrogen International , LTD.
Carbon Air Arching