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49-676: Wairakei is a small settlement, and geothermal area 8-kilometres (5 mi) north of Taupō , in the centre of the North Island of New Zealand , on the Waikato River . It is part of the Taupō Volcanic Zone and features several natural geysers, hot pools, boiling mud pools, and the Wairakei Power Station , a major geothermal electric power generating station. The station was the second large-scale geothermal facility worldwide, and

98-481: A landfill that was in proximity to abandoned coal mines, including the much-publicized Centralia, Pennsylvania , fire, which has been burning since 1962. Of the hundreds of mine fires in the United States burning today, most are found in the state of Pennsylvania . Some fires along coal seams are natural occurrences. Some coals may self-ignite at temperatures as low as 40 °C (104 °F) for brown coal in

147-458: A database (AMLIS), which in 1999 listed 150 fire zones. In mid-2010, according to OSM, more than 100 fires were burning beneath nine states, most of them in Colorado, Kentucky, Pennsylvania, Utah and West Virginia. Some geologists say that many fires go unreported, so that the actual number of them may be nearer to 200, across 21 states. In Pennsylvania, 45 fire zones are known, the most famous being

196-423: A fire requires fuel, oxygen, and heat . As underground fires are very difficult to reach directly, fire fighting involves finding an appropriate methodology which addresses the interaction of fuel and oxygen for the specific fire in question. A fire can be isolated from its fuel source, for example through firebreaks or fireproof barriers. Many fires, particularly those on steep slopes, can be completely excavated. In

245-555: A minuscule fraction of the country has been surveyed for coal fires. The best data available come from a study based on systematic, on-the-ground observation. In 1998, a total of 125 coal fires were located and mapped within a 2-kilometre strip either side of a 100-kilometre stretch of road north of Balikpapan to Samarinda in East Kalimantan, using hand-held Global Positioning System (GPS) equipment. Extrapolating this data to areas on Borneo and Sumatra underlain by known coal deposits, it

294-414: A near-surface coal-seam fire, its location and underground extent should be determined as precisely as possible. Besides studying the geographic, geologic and infrastructural context, information can be gained from direct measurements. These include: Underground coal mines can be equipped with permanently installed sensor systems. These relay pressure, temperature, airflow and gas composition measurements to

343-459: A once-quenched fire as the area dries. Accordingly, more energy must be removed than the fire generates. In practice these methods are combined, and each case depends on the resources available. This is especially true for water, for example in arid regions, and for covering material, such as loess or clay, to prevent contact with the atmosphere. Extinguishing underground coal fires, which sometimes exceed temperatures of 540 °C (1,000 °F),

392-488: A part of the city of Zwickau , a coal seam that had been burning since 1476 was only quenched in 1860. In Dudweiler , Saarland, a coal-seam fire ignited around 1668 and is still burning. This so-called Burning Mountain (" Brennender Berg ") soon became a tourist attraction and was even visited by Johann Wolfgang von Goethe . Also well-known is the so-called Stinksteinwand ( stinking stone wall ) in Schwalbenthal on

441-770: A population density of 3.2 people per km. Wairakei-Broadlands had a population of 1,236 at the 2018 New Zealand census , an increase of 84 people (7.3%) since the 2013 census , and an increase of 144 people (13.2%) since the 2006 census . There were 387 households, comprising 648 males and 588 females, giving a sex ratio of 1.1 males per female. The median age was 31.9 years (compared with 37.4 years nationally), with 315 people (25.5%) aged under 15 years, 261 (21.1%) aged 15 to 29, 555 (44.9%) aged 30 to 64, and 105 (8.5%) aged 65 or older. Ethnicities were 74.8% European/ Pākehā , 36.7% Māori , 4.4% Pacific peoples , 3.6% Asian , and 1.9% other ethnicities. People may identify with more than one ethnicity. The percentage of people born overseas

490-872: A problem which has gained international attention. In Saint-Etienne coal basin, five burning hills (montagnes de feu) have been described from the early 17th Century to the early 19th century around the city of Saint-Etienne. Some of these fires were reported burning for 3 centuries. Most of them were extinguished in 1785 These old burning hills correspond today to the Mont Salson , Bois d'Avaize and Cote Chaude in Saint-Etienne, la colline du Brûlé in la Ricamarie and Le mont du Feu (Mount of fire) in Genilac. The fire in Genilac lasted 30 years from 1740. Outcrops of pyrometamorphic rocks generated by these fires are visible today on Mont Salson and bois d'Avaize . In Planitz, now

539-426: A rural settlement, which covers 0.36 km (0.14 sq mi) and had an estimated population of 540 as of June 2024, with a population density of 1,500 people per km. The settlement is part of the larger Wairakei-Broadlands statistical area. Wairakei Village had a population of 507 at the 2018 New Zealand census , an increase of 54 people (11.9%) since the 2013 census , and an increase of 42 people (9.0%) since

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588-407: A serious health and safety hazard, affecting the environment by releasing toxic fumes; reigniting grass, brush, or forest fires; and causing subsidence of surface infrastructure such as roads, railways, pipelines, electric lines, bridge supports, buildings, and homes. Whether started by humans or by natural causes, coal-seam fires continue to burn for decades, centuries, or even millennia, until one of

637-405: A spark of static electricity to ignite the gas and start a coal explosion and fire. The same gas static is well known in ships and care has to be taken to ensure no such static sparking can occur. Two basic factors determine whether spontaneous combustion occurs or not, the ambient temperature and the grain size: Wildfires (lightning-caused or others) can ignite the coal close to the surface or

686-492: Is both highly dangerous and very expensive. Near-surface coal-seam fires are routinely extinguished in China following a standard method basically consisting of the following phases: Efforts are underway to refine this method, for example with additives to the quenching water or with alternative extinguishing agents. Underground coal-seam fires are customarily quenched by inertisation through mine rescue personnel. Toward this end

735-502: Is fueled by the presence of a magma chamber. In some rare cases it can be caused by underground fires or by large deposits of radioactive elements. Other sources of internal heating can be gravitational differentiation of substances, tidal friction , metamorphism , or phase transitions . The release of heat to the surface occurs either in the form of a conductive heat flow, or in the form of convective heat transfer by groundwater or gases . Fumaroles, or volcanic vents, are holes in

784-537: Is unable to reach the surface, causing pressure underground to rise until a critical point is reached and an explosion occurs, ejecting the superheated water along with the rock. Coal-seam fire A coal-seam fire is a burning of an outcrop or underground coal seam . Most coal-seam fires exhibit smouldering combustion, particularly underground coal-seam fires, because of limited atmospheric oxygen availability. Coal-seam fire instances on Earth date back several million years. Due to thermal insulation and

833-566: Is virtually certain these fires ignited new coal-seam fires. In 1944, Longyearbyen Mine #2 on Svalbard was set alight by sailors from the German battleship Tirpitz on its final sortie outside of Norwegian coastal waters. The mine continued to burn for 20 years, while some of the areas were subsequently mined from the reconstructed Mine #2b. Many coalfields in the US are subject to spontaneous ignition. The federal Office of Surface Mining (OSM) maintains

882-477: The 2006 census . There were 132 households, comprising 267 males and 240 females, giving a sex ratio of 1.11 males per female, with 153 people (30.2%) aged under 15 years, 114 (22.5%) aged 15 to 29, 204 (40.2%) aged 30 to 64, and 36 (7.1%) aged 65 or older. Ethnicities were 68.6% European/ Pākehā , 47.9% Māori , 6.5% Pacific peoples , 1.8% Asian , and 0.6% other ethnicities. People may identify with more than one ethnicity. Although some people chose not to answer

931-598: The Centralia mine fire in the Centralia mine in the hard coal region of Columbia County, which has been burning since 1962. Burning Mine, near Summit Hill , caught fire in 1859. In Colorado, coal fires have arisen as a consequence of fluctuations in the groundwater level, which can increase the temperature of the coal up to 300 °C, enough to cause it to spontaneously ignite . The Powder River Basin in Wyoming and Montana contains some 800 billion tons of brown coal, and

980-550: The Lewis and Clark Expedition (1804 to 1806) reported fires there. Fires have been a natural occurrence in this area for about three million years and have shaped the landscape. For example, an area about 4,000 square kilometres in size is covered with coal clinker , some of it in Theodore Roosevelt National Park , where there is a spectacular view of fiery red coal clinker from Scoria Point. The novel Germinal by

1029-535: The French novelist Emile Zola describes a fictional coal fire called Le Tartaret . The 1991 film Nothing but Trouble , directed and co-written by Dan Aykroyd , features a town, Valkenvania, that has an underground coal fire that has been burning for decades. The judge of the town references the constantly burning coal-mine fire as the source of his hatred of financiers. In the TV show Scorpion , Season 3, Episode 23 ,

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1078-514: The affected area is isolated by dam constructions in the galleries. Then an inert gas, usually nitrogen, is introduced, usually making use of available pipelines. In 2004, the Chinese government claimed success in extinguishing a mine fire at a colliery near Urumqi in China's Xinjiang province that had been burning since 1874. However, a March 2008 Time magazine article quotes researcher Steven Q. Andrews as saying, "I decided to go to see how it

1127-555: The avoidance of rain/snow extinguishment by the crust, underground coal-seam fires are the most persistent fires on Earth and can burn for thousands of years, like Burning Mountain in Australia. Coal-seam fires can be ignited by self-heating of low-temperature oxidation, lightning, wildfires and even arson. Coal-seam fires have been slowly shaping the lithosphere and changing atmosphere, but this pace has become faster and more extensive in modern times, triggered by mining. Coal fires are

1176-456: The case of near-surface coal-seam fires, the influx of oxygen in the air can be interrupted by covering the area or installing gas-tight barriers. Another possibility is to hinder the outflow of combustion gases so that the fire is quenched by its own exhaust fumes. Energy can be removed by cooling, usually by injecting large amounts of water. However, if any remaining dry coal absorbs water, the resulting heat of absorption can lead to re-ignition of

1225-421: The cauldron can be stable or highly variable, and is not related to the nature of the underlaying heat source. Geothermal heat and groundwater can interact in several ways. Geysers are the most well known hydrothermal feature. they occur when groundwater in underground cavities becomes superheated under a lid of colder surface water. When the superheated water breaches the surface, it flashes to steam, causing

1274-646: The census's question about religious affiliation, 69.2% had no religion, 18.3% were Christian , and 3.6% had Māori religious beliefs . Of those at least 15 years old, 21 (5.9%) people had a bachelor's or higher degree, and 87 (24.6%) people had no formal qualifications. 27 people (7.6%) earned over $ 70,000 compared to 17.2% nationally. The employment status of those at least 15 was that 174 (49.2%) people were employed full-time, 54 (15.3%) were part-time, and 36 (10.2%) were unemployed. Wairakei-Broadlands statistical area covers 410.00 km (158.30 sq mi) and had an estimated population of 1,320 as of June 2024, with

1323-698: The climate in parts of Indonesia becomes exceptionally dry from June to November due to the El Niño–Southern Oscillation off the west coast of South America. Since 1982, fire has been a recurring feature on the islands of Borneo and Sumatra, burning large areas in 1987, 1991, 1994, 1997–1998, 2001 and 2004. In October 2004 smoke from land clearing again covered substantial portions of Borneo and Sumatra, disrupting air travel, increasing hospital admissions, and extending to portions of Brunei, Singapore and Malaysia. Coal outcrops are so common in Indonesia it

1372-518: The country as well as the surrounding areas due to land subsidence and pollution. Coal and peat fires in Indonesia are often ignited by forest fires near deposits at the surface. It is difficult to determine when a forest fire is started by a coal-seam fire, or vice versa. The most common cause of forest fires and haze in Indonesia is intentional burning of forest to clear land for plantation crops of pulp wood, rubber and palm oil. No accurate count of coal-seam fires has been completed in Indonesia. Only

1421-576: The eastern slope of the Hoher Meißner , where several seams caught fire centuries ago after lignite coal mining ceased; combustion gas continues to reach the surface. In India, as of 2010, 68 fires were burning beneath a 58-square-mile (150 km ) region of the Jharia coalfield in Dhanbad, Jharkhand . Mine fires started in this region in 1916 and are rapidly destroying the only source of prime coking coal in

1470-497: The entrance of a mine, and the smouldering fire can spread through the seam, creating subsidence that may open further seams to oxygen and spawn future wildfires when the fire breaks to the surface. Prehistoric clinker outcrops in the American West are the result of prehistoric coal fires that left a residue that resists erosion better than the matrix, leaving buttes and mesa . It is estimated that Australia's Burning Mountain ,

1519-432: The following occurs: either the fuel source is exhausted, a permanent groundwater table is encountered, the depth of the burn becomes greater than the ground's capacity to subside and vent, or humans intervene. Because they burn underground, coal-seam fires are extremely difficult and costly to extinguish, and are unlikely to be suppressed by rainfall. There are strong similarities between coal fires and peat fires . Across

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1568-474: The ground from which volcanic vapors and gases escape to the atmosphere. Geothermally active areas are often located over an active magma chamber , which constantly releases hot gases that travel to the surface through cavities in the rock. Where these cavities reach the surface they form fumaroles. Areas where these vents are concentrated are known as Fumarole fields. Fumaroles tend to form concentrated deposits of sulfuric minerals, which fall out of suspension when

1617-418: The heated groundwater gathers in pools, forming hot springs. Where very little groundwater is available, rising hot groundwater in combination with microbial activity leads to the formation of mud pots. The behaviour of these mud pots can vary on a seasonal cycle based on variations in the amount of rainfall and the level of the water table. Hydrothermal explosions occur when a mass of superheated water

1666-425: The market, including heat-resistant grouts and a fire-smothering nitrogen foam , with other innovative solutions on the way. Some of the more notable mine fires around the world are listed below. In China, the world's largest coal producer with an annual output around 2.5 billion tons, coal fires are a serious problem. It has been estimated that some 10–200 million tons of coal uselessly burn annually, and that

1715-432: The oldest known coal fire, has burned for 6,000 years. Globally, thousands of inextinguishable mine fires are burning, especially in China where poverty, lack of government regulations and runaway development combine to create an environmental disaster. Modern strip mining exposes smouldering coal seams to the air, revitalizing the flames. Rural Chinese in coal-bearing regions often dig coal for household use, abandoning

1764-581: The pits when they become too deep, leaving highly combustible coal dust exposed to the air. Using satellite imagery to map China's coal fires resulted in the discovery of many previously unknown fires. The oldest coal fire in China is in Baijigou ( 白芨沟 , in Dawukou District of Shizuishan , Ningxia ) and is said to have been burning since the Qing Dynasty (before 1912). Before attempting to extinguish

1813-470: The presence of plants or animals that are aided by the coal fire. The prevalence of non-native plants can depend upon the fire's duration and the size of the affected area. For example, near a coal fire in Germany, many Mediterranean insects and spiders were identified in a region with cold winters, and it is believed that elevated ground temperatures above the fires permitted their survival. In order to thrive,

1862-429: The pressure below it to suddenly drop, which causes a chain reaction where most of the water in the geyser's feed system flashes to steam all at once. There are two main types of geyser. Fountain geysers, which erupt in violent bursts from a pool, and cone geysers, which erupt in steady jets for minutes at a time from a sinter cone of siliceous material that has been deposited surrounding the main vent. In other areas,

1911-433: The right conditions of moisture and grain size. The fire usually begins a foot or two inside the coal at a depth in which the permeability of the coal allows the inflow of air but in which the ventilation does not remove the heat which is generated. Self-ignition was a recognised problem in steamship times. One well known source of fires is mining breaking into a high pressure cavity of methane gas which on release can generate

1960-484: The safety monitoring personnel, giving them early warning of any problems. Besides destruction of the affected areas, coal fires often emit toxic gases, including carbon monoxide and sulphur dioxide . China's coal fires, which consume an estimated 20 – 200 million tons of coal a year, make up as much as 1 percent of the global carbon dioxide emissions from fossil fuels . One of the most visible changes will be subsidence . Another local environmental effect can include

2009-487: The same amount again is made inaccessible to mining. Coal fires extend over a belt across the entire north China , whereby over one hundred major fire areas are listed, each of which contains many individual fire zones. They are concentrated in the provinces of Xinjiang , Inner Mongolia and Ningxia . Beside losses from burned and inaccessible coal, these fires contribute to air pollution and considerably increased levels of greenhouse gas emissions and have thereby become

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2058-450: The surface and the oxygen required for their ignition comes from the atmosphere, and fires in deep underground mines, where the oxygen comes from ventilation. Mine fires may begin as a result of an industrial accident, generally involving a gas explosion. Historically, some mine fires were started when bootleg mining was stopped by authorities, usually by blowing the mine up. Many recent mine fires have started from people burning trash in

2107-563: The volcanic gases cool to the air. Ice cauldrons are a feature that occurs when an ice cap is affected by geothermal heating, either from active volcanism or the continuous heat production from an active geothermal area. Ice cauldrons can have many different appearances. These range from a smooth dent in the ice cap to deep holes with very steep walls formed by concentric rings of crevasses . The width of ice cauldrons can range from 50 meters up to around 10 kilometers, while depth can range from several meters to hundreds of meters. The shape of

2156-421: The world, thousands of underground coal fires are burning at any given moment. The problem is most acute in industrializing, coal-rich nations such as China. Global coal fire emissions are estimated to cause 40 tons of mercury to enter the atmosphere annually, and to represent three percent of the world's annual CO 2 emissions. Coal-seam fires can be divided into near-surface fires, in which seams extend to

2205-494: Was $ 32,700, compared with $ 31,800 nationally. 117 people (12.7%) earned over $ 70,000 compared to 17.2% nationally. The employment status of those at least 15 was that 516 (56.0%) people were employed full-time, 138 (15.0%) were part-time, and 51 (5.5%) were unemployed. Wairakei School is a co-educational state primary school, with a roll of 364 as of August 2024. The school opened in 1959. Geothermal activity Geothermal activity mostly appears in volcanic provinces, where it

2254-465: Was 12.9, compared with 27.1% nationally. Although some people chose not to answer the census's question about religious affiliation, 64.1% had no religion, 22.3% were Christian , 2.7% had Māori religious beliefs , 1.2% were Hindu , 0.2% were Muslim , 0.2% were Buddhist and 0.7% had other religions. Of those at least 15 years old, 75 (8.1%) people had a bachelor's or higher degree, and 210 (22.8%) people had no formal qualifications. The median income

2303-449: Was commissioned in 1958. It was listed in the book 70 Wonders Of The Modern World published in 2000 by Reader's Digest to record The Eventful 20th Century . The settlement, referred to as Wairakei Village, was constructed to house the workers of both the power station and the neighbouring Aratiatia hydro power station. From 31 October 2022 it had buses to Taupō, Mondays to Fridays. Statistics New Zealand describes Wairakei Village as

2352-580: Was estimated that more than 250,000 coal-seam fires may have been burning in Indonesia in 1998. Land clearing practices which use fire, often starting forest fires, may be the cause of coal-seam fires in Indonesia. In 1982 and 1983 one of the largest forest fires in this century raged for several months through an estimated 5 million hectares of Borneo's tropical rainforests. Goldammer and Seibert however concluded that there are indications that coal-seam fires already occurred between 13,200 and 15,000 BP . A fire season usually occurs every 3 to 5 years, when

2401-545: Was extinguished, and flames were visible and the entire thing was still burning. ... They said it was put out, and who is to say otherwise?" A jet engine unit, known as Gorniczy Agregat Gasniczy (GAG), was developed in Poland and successfully used for fighting coal fires and displacing firedamp in mines. Time magazine reported in July 2010 that less expensive alternatives for extinguishing coal-seam fires were beginning to reach

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