 | This article needs additional citations for verification .(March 2013) (Learn how and when to remove this template message) |
In mining, a windblast is a sudden rush of air or gas due to the collapse of a void.
| | This article needs additional citations for verification .(March 2013) (Learn how and when to remove this template message) |
In mining, a windblast is a sudden rush of air or gas due to the collapse of a void.
Windblast is common in longwall coal mines, especially those whose roof strata are competent, and do not cave immediately behind the roof supports as the face advances. This results in the tendency for a large void to be created behind the roof supports in the goaf (or gob) which collapses when the overlying cantilevered strata can no longer support its own weight. When the collapse occurs, the air or gas occupying the void is displaced by rock, resulting in a pressure wave and windblast that propagates along the roadways (tunnels) of the mine. This may be followed by a "suck back" as the air pressure is equalised with the low pressure created higher up in the goaf.
Windblast can also occur in metalliferous, kimberlite or even evaporite mines, particularly in block caving mines, as happened at the Northparkes mine in NSW, Australia on 25 November 1999, killing 4. [1]
The effects of a windblast are not limited to the physical effects of the overpressure wave. The effects of a windblast include:
Broken bones and fatalities are not uncommon outcomes from serious windblast events. [1] [2]
Windblast prevention is centred on not allowing the void to form in the first place. This can be somewhat achieved through careful mine planning. Windblast prevention also relies on monitoring to ensure the void does not form (and stopping production if one does begin to form), and the use of different methods to try to promote caving, such as hydraulic fracturing [3] and the use of explosives.
Harm minimisation seeks to minimise the damage to persons and machinery if a wind blast does occur. This may involve the following:
Windblast should not be confused with an outburst, which is the sudden and violent ejection of rock and gas from a coal seam and the surrounding strata.[ citation needed ]
A bomb is an explosive weapon that uses the exothermic reaction of an explosive material to provide an extremely sudden and violent release of energy. Detonations inflict damage principally through ground- and atmosphere-transmitted mechanical stress, the impact and penetration of pressure-driven projectiles, pressure damage, and explosion-generated effects. Bombs have been utilized since the 11th century starting in East Asia.
Underground hard rock mining refers to various underground mining techniques used to excavate hard minerals, usually those containing metals such as ore containing gold, silver, iron, copper, zinc, nickel, tin and lead, but also involves using the same techniques for excavating ores of gems such as diamonds or rubies. Soft rock mining refers to excavation of softer minerals such as salt, coal, or oil sands.
A bunker is a defensive military fortification designed to protect people and valued materials from falling bombs or other attacks. Bunkers are mostly underground, in contrast to blockhouses which are mostly above ground. They were used extensively in World War I, World War II, and the Cold War for weapons facilities, command and control centers, and storage facilities. Bunkers can also be used as protection from tornadoes.
Coal mining is the process of extracting coal from the ground. Coal is valued for its energy content and since the 1880s, has been widely used to generate electricity. Steel and cement industries use coal as a fuel for extraction of iron from iron ore and for cement production. In the United Kingdom and South Africa, a coal mine and its structures are a colliery, a coal mine is a 'pit', and the above-ground structures are a 'pit head'. In Australia, "colliery" generally refers to an underground coal mine. In the United States, "colliery" has been used to describe a coal mine operation, but this usage is less common.
Mount Kembla is a suburb and a mountain in the Illawarra region of New South Wales, Australia.
A blast injury is a complex type of physical trauma resulting from direct or indirect exposure to an explosion. Blast injuries occur with the detonation of high-order explosives as well as the deflagration of low order explosives. These injuries are compounded when the explosion occurs in a confined space.
Easington Colliery is a town in County Durham, England, known for a history of coal mining. It is situated to the north of Horden, and a short distance to the east of Easington Village. The town suffered a significant mining accident on 29 May 1951, when an explosion in the mine resulted in the deaths of 83 men.
Longwall mining is a form of underground coal mining where a long wall of coal is mined in a single slice. The longwall panel is typically 3–4 km (1.9–2.5 mi) long and 250–400 m (820–1,310 ft) wide.
A blast shelter is a place where people can go to protect themselves from blasts and explosions, like those from bombs, or in hazardous worksites, such as on oil and gas refineries or petrochemical facilities. It differs from a fallout shelter, in that its main purpose is to protect from shock waves and overpressure instead of from radioactive precipitation, as a fallout shelter does. It is also possible for a shelter to protect from both blasts and fallout.
Explosives safety originated as a formal program in the United States in the aftermath of World War I when several ammunition storage areas were destroyed in a series of mishaps. The most serious occurred at Picatinny Arsenal Ammunition Storage Depot, New Jersey, in July, 1926 when an electrical storm led to fires that caused explosions and widespread destruction. The severe property damage and 19 fatalities led Congress to empower a board of Army and Naval officers to investigate the Picatinny Arsenal disaster and determine if similar conditions existed at other ammunition depots. The board reported in its findings that this mishap could recur, prompting Congress to establish a permanent board of colonels to develop explosives safety standards and ensure compliance beginning in 1928. This organization evolved into the Department of Defense Explosives Safety Board (DDESB) and is chartered in Title 10 of the US Code. The DDESB authors Defense Explosives Safety Regulation (DESR) 6055.9 which establishes the explosives safety standards for the Department of Defense. The DDESB also evaluates scientific data which may adjust those standards, reviews and approves all explosives site plans for new construction, and conducts worldwide visits to locations containing US title munitions. The cardinal principle of explosives safety is expose the minimum number of people for the minimum time to the minimum amount of explosives.
Blackdamp is an asphyxiant, reducing the available oxygen content of air to a level incapable of sustaining human or animal life. It is not a single gas but a mixture of unbreathable gases left after oxygen is removed from the air and typically consists of nitrogen, carbon dioxide and water vapour. The suffix damp is believed to derive from the German word for vapours ("Dampf"). The word damp is used in similar mining terms such as white damp, fire damp and stink damp.
Mine exploration is a hobby in which people visit abandoned mines, quarries, and sometimes operational mines. Enthusiasts usually engage in such activities for the purpose of exploration and documentation, sometimes through the use of surveying and photography. In this respect, mine exploration might be considered a type of amateur industrial archaeology. In many ways, however, it is closer to caving, with many participants actively interested in exploring both mines and caves. Mine exploration typically requires equipment such as helmets, head lamps, Wellington boots, and climbing gear.
Clifton Hall Colliery was one of two coal mines in Clifton on the Manchester Coalfield, historically in Lancashire which was incorporated into the City of Salford in Greater Manchester, England in 1974. Clifton Hall was notorious for an explosion in 1885 which killed around 178 men and boys.
A dust explosion is the rapid combustion of fine particles suspended in the air within an enclosed location. Dust explosions can occur where any dispersed powdered combustible material is present in high-enough concentrations in the atmosphere or other oxidizing gaseous medium, such as pure oxygen. In cases when fuel plays the role of a combustible material, the explosion is known as a fuel-air explosion.
A rupture disk, also known as a pressure safety disc, burst disc, bursting disc, or burst diaphragm, is a non-reclosing pressure relief safety device that, in most uses, protects a pressure vessel, equipment or system from overpressurization or potentially damaging vacuum conditions.
An outburst is the sudden and violent ejection of coal, gas and rock from a coal face and surrounding strata in an underground coal mine. When outbursts occur, they can be very serious events, possibly even resulting in fatalities.
The health and environmental impact of the coal industry includes issues such as land use, waste management, water and air pollution, caused by the coal mining, processing and the use of its products. In addition to atmospheric pollution, coal burning produces hundreds of millions of tons of solid waste products annually, including fly ash, bottom ash, and flue-gas desulfurization sludge, that contain mercury, uranium, thorium, arsenic, and other heavy metals. Coal is the largest contributor to the human-made increase of carbon dioxide in Earth's atmosphere.
Blast-related ocular trauma comprises a specialized group of penetrating and blunt force injuries to the eye and its structure caused by the detonation of explosive materials. The incidence of ocular trauma due to blast forces has increased dramatically with the introduction of new explosives technology into modern warfare. The availability of these volatile materials, coupled with the tactics of contemporary terrorism, has caused a rise in the number of homemade bombs capable of extreme physical harm.
This is a partial glossary of coal mining terminology commonly used in the coalfields of the United Kingdom. Some words were in use throughout the coalfields, some are historic and some are local to the different British coalfields.
Mine safety is a broad term referring to the practice of controlling and managing a wide range of hazards associated with the life cycle of mining-related activities. Mine safety practice involves the implementation of recognised hazard controls and/or reduction of risks associated with mining activities to legally, socially and morally acceptable levels. While the fundamental principle of mine safety is to remove health and safety risks to mine workers, mining safety practice may also focus on the reduction of risks to plant (machinery) together with the structure and orebody of the mine.