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Thirteen miners died as a result of 2 explosions in the Jim Walter Resources No. 5 mine near Brookwood AL in September 2001. Both explosions were ignited in intake air entries, and both were probably ignited by electrical equipment. With few exceptions, permissible equipment is not required in intake air entries of US underground coal mines. Researchers with the NIOSH Pittsburgh Research Laboratory studied the electrical equipment ignition sources for the Brookwood and other disasters to develop recommendations for preventing similar disasters. Adherence to National Electrical Code© requirements for flexible cords installed in hazardous (classified) locations may have prevented the second massive Brookwood explosion. The 30 CFR Part 7 requirements for battery assemblies should be reevaluated, taking into consideration United Mine Workers of America recommendations and the Zone 1 "increased safety" standard requirements for battery assemblies. Class 1 Division 2 or Zone 2 explosion protection techniques are recommended for intake air equipment so that they do not present a methane-air ignition source under normal operation, before mine power is shut down during emergencies. Battery powered circuits in intake air that are likely to remain energized during emergencies should be protected by more stringent protection techniques, to protect rescue/recovery personnel.
| Author(s): | Dubaniewicz-TH |
| Reference: | IAS '07: Conference Record of the IEEE Industry Applications Conference, 42nd IAS Annual Meeting, New Orleans, LA, September 23-27, 2007. Piscataway, NJ: Institute of Electrical and Electronics Engineers, Inc. 2007 Sep; 4:1353-1359 |
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