“Obstructions such as roof falls and standing water in bleeder systems can severely restrict ventilation and prevent proper weekly examination to evaluate the effectiveness of the bleeder system,” the agency said recently, noting that past mine explosions had been attributed to inadequate ventilation.

 

MSHA urges mines to perform a complete evaluation of its bleeder system, including methane, air quantity and oxygen measurements while ensuring that air is moving in the proper direction.

 

While traveling, consistently monitor for methane and low oxygen levels using only approved and properly calibrated handheld gas monitors. If roof falls occur or are encountered, clean up debris that could obstruct the bleeder’s air flow.

 

Fan records should also be monitored for ventilation pressure increases, as such rises could indicate an airway obstruction. Bleeders should also be kept free of water accumulations at all times.

 

All bleeder examinations should include compliance to the communications and tracking procedures in the mine’s emergency response plan.

 

To enhance safety in the area, federal officials stress that mines should establish a self-contained self rescuer cache in bleeder entries that will accommodate the number of workers traveling the systems.

 

For a printable, distributable version of this safety alert, visit the MSHA website.