A 62-year-old contractor sustained fatal injuries when three methane ignitions occurred in an air shaft, says the Mine Safety and Health Administration (MSHA).
The victim and three contractors were preparing to seal the intake air shaft of an underground mine. At the time of the ignitions, the victim was trimming metal so that it would fit inside wooden forms and was in direct line of the ignition forces.
Best Practices:
- Do not use cutting torches near unventilated air shafts. Allow no sparking or hot metal from grinding or torching to drop into an air shaft opening. Install non-combustible barriers below welding, cutting, or soldering operations in or over a shaft.
- Conduct proper examinations for methane immediately before and during welding, cutting, soldering or using any spark causing tool (grinder, drills, etc.), especially in areas likely to contain methane. At an air shaft, monitor for methane continuously, at appropriate levels, including the bottom of the air shaft.
- Use properly calibrated methane detectors that can detect concentrations greater than 5%.
- Be aware of potential hazards when working around a shaft opening. Take additional safety precautions when the barometric pressure changes.
- Continuously ventilate an air shaft until the last moment before pouring concrete to seal the shaft.
- Make sure all employees are tied off while working around the shaft opening.
- Provide adequate training on the characteristics of mine gases and in the use of handheld gas detectors, including the use of extendable probes or pumps.
