Mine explosions can also be triggered when fine particles of coal dust come into contact with a source of heat. While methane is easier to ignite, the explosion pressure and heat value of methane is not as high as coal dust. In most cases, dust explosions are first caused by methane explosions, said Luo.
Why are there explosions in coal mines?
Coal mine explosions are generally caused by either methane or coal dust. Methane gas is a byproduct of coal. It can build up over time in coal mines when there are not enough other types of gases to dilute it to prevent an explosion. … Explosions happen when the methane comes in contact with a heat source.
Which gas causes explosion in coal mines?
There are two main types of coalmine explosions: methane and coal dust. Methane explosions occur when a buildup of methane gas contacts a heat source and there is not enough air to dilute the gas level below its explosion point.
Why is working in a coal mine dangerous?
Working in coal mines is dangerous — miners have to deal with toxic gases, plus the threat of being crushed, drowned, or injured from fires and explosions. Some miners love it.
How do you stop coal dust explosions?
Coal dust explosions in underground coal mines are prevented by generous application of rock dust (usually limestone). If an explosion should occur, the rock dust disperses, mixes with the coal dust and prevents flame propagation by acting as a thermal inhibitor or heat sink.
Why is coal dust more dangerous than coal?
Coal dust suspended in air is explosive—coal dust has far more surface area per unit weight than lumps of coal, and is more susceptible to spontaneous combustion. As a result, a nearly empty coal store is a greater explosion risk than a full one.
What caused the Westray mine disaster?
Early in the morning beneath the small town of Plymouth, Nova Scotia, a methane gas leak into the Westray mine shaft from the Foord coal seam mixed with coal dust and caused in an explosion. … The nearby Allan mine, which closed in 1951, experienced eight methane explosions in its 40-years of operations.
What gas kills miners?
Black Damp – Carbon Dioxide (CO2)
Black damp is the mining term for the suffocating mixture of carbon dioxide and other unbreathable gases that can build-up in mines causing poisoning, asphyxiation, and ultimately death if left untreated.
Which gas is found in coal?
Coal gas, gaseous mixture—mainly hydrogen, methane, and carbon monoxide—formed by the destructive distillation (i.e., heating in the absence of air) of bituminous coal and used as a fuel. Sometimes steam is added to react with the hot coke, thus increasing the yield of gas.
Does coal contain methane?
Coal mine methane (CMM) refers to methane released from the coal and surrounding rock strata due to mining activities. In underground mines, it can create an explosive hazard to coal miners, so it is removed through ventilation systems.
What is the average age of a coal miner?
Does mining pay well?
According to the Bureau of Labor Statistics, the average miner in the U.S. earns an hourly wage of $27.62, over the course of a 43.6 hour work week, as of 2012. This amounts to an annual salary of $62,620. However, wages vary based on location and specific job duties.
Is mining coal dangerous?
Open cut hazards are principally mine wall failures and vehicle collisions; underground mining hazards include suffocation, gas poisoning, roof collapse, rock burst, outbursts, and gas explosions. Firedamp explosions can trigger the much-more-dangerous coal dust explosions, which can engulf an entire pit.
How does removing the overburden during coal extraction affect the environment?
Strip mining eliminates existing vegetation and alters the soil profile, or the natural soil layers. Mining disturbs and may even destroy the beneficial micro-organisms in the topsoil. Soil also may be damaged if reclamation operations mix the topsoil with subsoils, diluting matter in the surface soil.
Why there is much more mine dust than normal dust?
Dusts have a very large surface area compared to their mass. … This greatly-increased surface area allows the material to burn much faster, and the extremely small mass of each particle allows them to catch on fire with much less energy than the bulk material, as there is no heat loss to conduction within the material.
Why is methane explosive?
Methane explosions occur in mines when a buildup of methane gas, a byproduct of coal, comes into contact with a heat source, and there is not enough air to dilute the gas to levels below its explosion point, said Yi Luo, an associate professor of mining engineering at West Virginia University.