COAL MINES FACE COLD WEATHER DANGERS
Safety Article by Harold Hough August/September 2009
Over one hundred years ago, the worst mining disaster in US
history occurred. At about 10:20 in the morning on a bright
December day in 1907 an explosion erupted from the No. 8 coal
mine at Monongah, West Virginia. As the flames boiled out of
the shaft, they threw the concrete roof of the engine house
into the air and 500 feet away. The boiler and fan building
disappeared along with their workers as pieces were thrown half
a mile away. What coal dust didn't explode flew out of the shafts
and covered the river water with a dark covering.
Underground, things were worse. 362 miners died in the explosion,
cave-ins and fires that followed. What should have been the
beginning of the joyous Christmas season became a period of
mourning as hundreds of families lost family and breadwinners.
What happened that December wasn't isolated. Since 1900, 250
mine explosions have occurred during the winter season, killing
nearly 7,000 people and making it the most dangerous season
for mining coal.
The winter is especially dangerous for coal mines because of
the changing weather. As the barometric pressure drops during
the colder weather, more methane seeps from the coal into the
mine atmosphere, creating a greater explosion risk. In addition,
the dry condition makes coal dust more likely to remain suspended
in the air while there is a greater risk of sparks from static
electricity.
Although mine regulations have decreased the risk over the years,
the winter season still poses a risk. According to the Mining
Safety and Health Administration (MSHA), the worst mining disasters
have occurred between October and March. Historically December,
January, and March have been the worst months in terms of explosions
and fatalities.
MINIMIZING THE RISK
MSHA has made several recommendations to coal mines to lower
the risk of coal weather explosions. Although they are common
sense suggestions, they provide a reminder of the increased
dangers during the cold weather.
FOLLOW MINE APPROVED VENTILATION PLAN. This is important and
one reason why every mine must have an individually improved
ventilation plan. This plan isn't necessary just for miners,
but is also critical to keeping methane at safe levels in the
mine, even during low barometric pressure weather.
It's important to remember that methane doesn't just seep from
coal in the work area. Areas that have been worked out and even
collapsed are still producing methane. So, while work areas
may be safe, explosive levels of gas may bee accumulating in
other areas of the mine, especially if the miners ignore the
air circulation in them. That is why all areas not sealed must
be properly ventilated.
Not only must the ventilation system remove these accumulations,
it has to maintain a proper air pressure differential so the
methane is carried away from working areas where there is a
greater risk of sparking.
CONDUCT REGULARLY SCHEDULED HAZARD INSPECTIONS. Problems are
usually noticed during regularly scheduled inspections. While
some inspections focus on methane accumulation, others look
at the air shafts, air movement and escape routes to prevent
problems in the future.
PROPER MAINTENANCE REDUCES EXPLOSION RISKS. Since equipment
in the mine is a potential source of sparking, proper maintenance
limits this risk and can prevent an explosion, even if methane
or coal dust accumulates.
COMPLETE ROCK DUSTING IN ALL AREAS OF THE MINE. Although coal
dust explosions are rare, it does have an even greater explosive
potential than methane and cause a gas explosion to propagate
to other parts of the mine. There is no better example of the
damage that coal dust can cause than the Monongah incident where
coal dust caused the explosion to propagate from the mine to
the surface, where it destroyed several buildings and killed
many workers.
NEVER SMOKE OR CARRY SMOKING MATERIALS INTO AN UNDERGROUND MINE.
Although this may seem like common sense, many mine explosions
have been traced to smoking. In many cases, the miner excuses
his smoking by saying that the mine doesn't have problems with
methane.
A safe history doesn't mean that a combination of incidents
couldn't cause a problem. For instance, the unnaturally low
barometric conditions may cause more methane to seep into the
mine, which accumulates because the ventilation system, which
is okay under normal circumsatnces, is now overloaded. Suddenly,
lighting a cigarette becomes the final link in a catastrophe.
Admittedly, some things can't be controlled like low barometric
pressure and dry conditions. However, by paying close attention
to the other factors, a mine can offset the risks. It's up to
each one of us to make sure that the final link in a mine explosion
is never put in place.
