Blackdamp (also known as stythe or choke damp) 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 term is etymologically and practically related to terms for other underground mine gases such as fire damp, white damp, stink damp, and afterdamp.
The meaning of "damp" in this term, while most commonly understood to imply humidity, presents evidence of having been separated from that newer, irrelevant meaning at least by the first decade of the 18th century, where the original relevant meaning of "vapor" derives from a Proto-Germanic origin, dampaz, which gave rise to its immediate English predecessor, the Middle Low German damp (with no record of an Old English intermediary). The proto-Germanic dampaz gave rise to many other cognates, including the Old High German damph, the Old Norse dampi, and the modern German Dampf, the last of which still translates as "vapor". [1]
Blackdamp is encountered in enclosed environments such as mines, sewers, wells, tunnels and ships' holds. It occurs with particular frequency in abandoned or poorly ventilated coal mines. Coal, once exposed to the air of a mine, naturally begins absorbing oxygen and exuding carbon dioxide and water vapor. The amount of blackdamp exuded by a mine varies based on a number of factors, including the temperature (coal releases more carbon dioxide in the warmer months), the amount of exposed coal, and the type of coal, although all mines with exposed coal produce gas.
Blackdamp is considered a particularly pernicious type of damp (especially in a historical context), due to its omnipresence where exposed coal is found, and slow onset of symptoms. It produces no obvious odor (unlike the hydrogen sulfide of stinkdamp), is constantly being reintroduced to the air (instead of being released in pockets from actively mined sections), and does not require combustion in order to be released (unlike whitedamp or afterdamp). Many of the initial symptoms of oxygen deprivation (dizziness, light-headedness, drowsiness and poor coordination) are relatively innocuous and can easily be mistaken for simple fatigue, given the physically strenuous job of coal mining. The time between the onset of initial symptoms and the start of frank asphyxiation (and rapid unconsciousness) can be as short as seconds. Thus, if the warning signs are missed, a large number of miners can be rapidly incapacitated in the same short period of time, leaving no one to summon help.
In addition to the danger inside the mine, blackdamp can be "exhaled" in large quantities from mines (especially long-abandoned coal mines with few outlets for escaping gas) during sudden changes in atmospheric pressure, potentially causing asphyxiation on the surface. [2]
The gas mixture has been responsible for many deaths among underground workers, especially miners—for example, the Hartley Colliery disaster, when 204 men and boys were trapped when the beam of an engine suddenly broke and fell down the single shaft, damaging the ventilation system and blocking it with debris. Despite rescuers' efforts, they could not be reached before they suffocated in the blackdamp atmosphere.
Historically, the domestic canary was used as an early warning against carbon monoxide.
In active mining operations, the threat from blackdamp is addressed with proper mineshaft ventilation as well as various detection methods, typically using miner's safety lamps or hand-held electronic gas detectors. The safety lamp is merely a specially designed lantern with a flame that is designed to automatically extinguish itself at an oxygen concentration of approximately 18% (normal atmospheric concentration of oxygen is c. 21%). This low detection threshold gives miners an unmistakable warning and allows them to escape before any potentially incapacitating effects are felt.
Carbon dioxide is a chemical compound with the chemical formula CO2. It is made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature, and as the source of available carbon in the carbon cycle, atmospheric CO2 is the primary carbon source for life on Earth. In the air, carbon dioxide is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. Carbon dioxide is soluble in water and is found in groundwater, lakes, ice caps, and seawater. When carbon dioxide dissolves in water, it forms carbonate and mainly bicarbonate, which causes ocean acidification as atmospheric CO2 levels increase.
The Davy lamp is a safety lamp used in flammable atmospheres, invented in 1815 by Sir Humphry Davy. It consists of a wick lamp with the flame enclosed inside a mesh screen. It was created for use in coal mines, to reduce the danger of explosions due to the presence of methane and other flammable gases, called firedamp or minedamp.
Coal mining is the process of extracting coal from the ground or from a mine. 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 called a "pit", and above-ground mining structures are referred to as a "pit head". In Australia, "colliery" generally refers to an underground coal mine.
Firedamp is any flammable gas found in coal mines, typically coalbed methane. It is particularly found in areas where the coal is bituminous. The gas accumulates in pockets in the coal and adjacent strata and when they are penetrated the release can trigger explosions. Historically, if such a pocket was highly pressurized, it was termed a "bag of foulness".
The Blantyre mining disaster, which happened on the morning of 22 October 1877, in Blantyre, Scotland, was Scotland's worst ever mining accident. Pits No. 2 and No. 3 of William Dixon's Blantyre Colliery were the site of an explosion which killed 207 miners, possibly more, with the youngest being a boy of 11. It was known that firedamp was present in the pit and it is likely that this was ignited by a naked flame. The accident left 92 widows and 250 fatherless children.
Afterdamp is the toxic mixture of gases left in a mine following an explosion caused by methane-rich firedamp, which itself can initiate a much larger explosion of coal dust. The term is etymologically and practically related to other terms for underground mine gases—such as firedamp, white damp, and black damp, with afterdamp being composed, rather, primarily by carbon dioxide, carbon monoxide and nitrogen, with highly toxic stinkdamp-constituent hydrogen sulfide possibly also present. However, the high content of carbon monoxide is the component that kills, preferentially combining with haemoglobin in the blood and thus depriving victims of oxygen. Globally, afterdamp has caused many of the casualties in disasters of pit coalfields, including British, such as the Senghenydd colliery disaster. Such disasters continue to afflict working mines, for instance in mainland China.
John Scott Haldane was a British physician physiologist and philosopher famous for intrepid self-experimentation which led to many important discoveries about the human body and the nature of gases. He also experimented on his son, the celebrated and polymathic biologist J. B. S. Haldane, even when he was quite young. Haldane locked himself in sealed chambers breathing potentially lethal cocktails of gases while recording their effect on his mind and body.
A safety lamp is any of several types of lamp that provides illumination in places such as coal mines where the air may carry coal dust or a build-up of inflammable gases, which may explode if ignited, possibly by an electric spark. Until the development of effective electric lamps in the early 1900s, miners used flame lamps to provide illumination. Open flame lamps could ignite flammable gases which collected in mines, causing explosions; safety lamps were developed to enclose the flame to prevent it from igniting the explosive gases. Flame safety lamps have been replaced for lighting in mining with sealed explosion-proof electric lights, but continue to be used to detect gases.
The Monongah mining disaster was a coal mine explosion on December 6, 1907, at Fairmont Coal Company's Nos. 6 and 8 mines in Monongah, West Virginia, which killed 362 miners. It has been described as "the worst mining disaster in American history" and was one of the contributing events that led to the creation of the United States Bureau of Mines.
The Felling Colliery in Britain, suffered four disasters in the 19th century, in 1812, 1813, 1821 and 1847. By far the worst of the four was the 1812 disaster which claimed 92 lives on 25 May 1812. The loss of life in the 1812 disaster was one of the motivators for the development of miners' safety lamps such as the Geordie lamp and the Davy lamp.
A self-contained self-rescue device, SCSR, self-contained self-rescuer, or air pack is a portable oxygen source for providing breathable air when the surrounding atmosphere lacks oxygen or is contaminated with toxic gases, e.g. carbon monoxide.
Whitedamp is a noxious mixture of gases formed by the combustion of coal, usually in an enclosed environment such as a coal mine. The main, most toxic constituent is carbon monoxide, which causes carbon monoxide poisoning. Hydrogen sulfide, also called stinkdamp, may co-occur. Coal frequently starts to burn slowly in mines when it is exposed to the atmosphere; partial combustion produces carbon monoxide. The term is etymologically and practically related to terms for other underground mine gases such as firedamp, black damp, stink damp, and afterdamp.
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.
An asphyxiant gas, also known as a simple asphyxiant, is a nontoxic or minimally toxic gas which reduces or displaces the normal oxygen concentration in breathing air. Breathing of oxygen-depleted air can lead to death by asphyxiation (suffocation). Because asphyxiant gases are relatively inert and odorless, their presence in high concentration may not be noticed, except in the case of carbon dioxide (hypercapnia).
In mining, a windblast is a sudden rush of air or gas due to the collapse of a void.
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.
The Brunner Mine disaster happened at 9:30 am on Thursday 26 March 1896, when an explosion deep in the Brunner Mine, in the West Coast region of New Zealand, killed all 65 miners below ground. The Brunner Mine disaster is the deadliest mining disaster in New Zealand's history.
The Avondale Mine disaster was a massive fire at the Avondale Colliery near Plymouth Township, Pennsylvania, on September 6, 1869. It caused the death of 110 workers. It started when the wooden lining of the mine shaft caught fire and ignited the coal breaker built directly overhead. The shaft was the only entrance and exit to the mine, and the fire trapped and suffocated 108 of the workers. It was the greatest mine disaster to that point in American history.
The Scofield Mine disaster was a mining explosion that occurred at the Winter Quarters coal mine on May 1, 1900. The mine was located at 39°42′57″N111°11′17″W near the town of Scofield, Utah. In terms of life lost, it was the worst mining accident at that point in American history. The explosion is also a key element in the plot of the Carla Kelly novel My Loving Vigil Keeping.
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.