WINTER SAFETY ISSUES FACE EASTERN COAL MINES
Eastern Edition Safety Article by Harold Hough Jan. 2012
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. That’s why the Mining Safety and Health Administration (MSHA) instituted Winter Alert 2011 - "Knock Out the Risk, Check Your List." "Conditions at underground and surface coal mines can change dramatically during the winter months," said Joseph A. Main, assistant secretary of labor for mine safety and health. "We must be ever mindful of the seasonal changes that can affect our work environments."
An example of the risk was seen over one hundred years ago when 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.
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. Other hazards include limited visibility, icy haulage roads and walkways, and the freezing and thawing effect on highwalls at surface mines.
Although mine regulations have decreased the risk over the years, the winter season still poses a risk. According to 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 also 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.
BE AWARE OF RISKS IN OPEN PIT MINES. It’s easy to ignore winter methane problems in open pit mines. However, exposure to the outside weather and temperatures poses risks too. Miners and operators of surface mines should examine the stability of highwalls, remove snow and ice from walkways, de-ice any equipment, and apply salt and sand liberally where needed.
CONDUCT REGULARLY SCHEDULED HAZARD EXAMINATIONS. Underground coal mines are dynamic work environments where working conditions change rapidly and without warning. Examinations are the first line of defense for miners working in underground coal mines. Problems are usually noticed during these examinations. While some inspections focus on methane accumulation, others look at the roof conditions, 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 circumstances, 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.