An adit (from Latin aditus, entrance)[1] or stulm[2] is a horizontal or nearly horizontal passage to an underground mine.[3] Miners can use adits for access, drainage,[4] ventilation, and extracting minerals at the lowest convenient level.[1] Adits are also used to explore for mineral veins.[1] Although most strongly associated with mining, the term adit is sometimes also used in the context of underground excavation for non-mining purposes; for example, to refer to smaller underground passageways excavated for underground metro systems, to provide pedestrian access to stations (pedestrian adits), and for access required during construction (construction adits).[5]
Gated entrance of an abandoned adit near Medford, Oregon, United States
Adits are driven into the side of a hill or mountain, and are often used when an ore body is located inside the mountain but above the adjacent valley floor or coastal plain. In cases where the mineral vein outcrops at the surface, the adit may follow the lode or vein until it is worked out, in which case the adit is rarely straight. The use of adits for the extraction of ore is generally called drift mining.
Adits can only be driven into a mine where the local topography permits. There will be no opportunity to drive an adit to a mine situated on a large flat plain, for instance. Also if the ground is weak, the cost of shoring up a long adit may outweigh its possible advantages.
Access and ventilationedit
Horse adit in the abandoned lead mine, Nenthead, County Durham, UK
Access to a mine by adit has many advantages over the vertical access shafts used in shaft mining. Less energy is required to transport miners and heavy equipment into and out of the mine. It is also much easier to bring ore or coal out of the mine. Horizontal travel by means of narrow gauge tramway or cable car is also much safer and can move more people and ore than vertical elevators. In the past horses and pit ponies were used.
In combination with shafts, adits form an important element in the ventilation of a mine: in simple terms, cool air will enter through an adit, be warmed by the higher temperature underground and will naturally exhaust from vertical shafts, some of which are sunk specifically for this purpose.[6]
Drainageedit
Two Brothers Adit, a small surviving mine entrance at the site of Eylesbarrow mine, Dartmoor, Devon
Most adits are designed to slope slightly upwards from the entrance so that water will flow freely out of the mine.[7] Mines that have adits can be at least partly drained of water by gravity alone or power-assisted gravity. The depth to which a mine can be drained by gravity alone is defined by the deepest open adit which is known as the "drainage adit".[8] The term mine drainage tunnel is also common, at least in the United States. Workings above this level (known as "above adit") will remain unflooded as long as the adit does not become blocked. All mine workings below both the drainage adit ("below adit") and the water table will flood unless mechanical means are used for drainage. Until the invention of the steam engine this was the main restriction on deep mining. Adits are useful for deeper mines. Water only needs to be raised to the drainage adit rather than to the surface.
Because of the great reduction in ongoing costs that a drainage adit can provide, they have sometimes been driven for great distances for this purpose. One example is the Milwr tunnel in North Wales, which is about ten miles (16 km) long. Other examples are the Great County Adit in Cornwall, a 40-mile (64 km)-long network of adits that used to drain the whole Gwennap mining area, and the 3.9 miles (6.3 km) Sutro Tunnel at the Comstock Lode in Virginia City, Nevada. A side benefit of driving such extensive adits is that previously unknown ore-bodies can be discovered, helping finance the enormous cost.[8]
Adits were used in Cornwall before 1500, and were important to the tin and copper mines in Cornwall and Devon because the ore-bearing veins are nearly vertical, thus acting as ingress channels for water.[7]
Great County Adit, a system of over 40 miles (65 km) of adits used for dewatering more than 100 mines in the Gwennap area of Cornwall in the 18th and early 19th centuries.
Milwr tunnel, a 10-mile long (16 km) drainage adit in North Wales. Started in 1897, it still discharges an average of 87 million litres (23 million US gallons) of water per day from the disused Halkyn District United Mines.
Black Trout Adit in Tarnowskie Góry, Poland. Part of a former silver mine, the adit was used for removing water from the mine. It still carries water from old galleries to the nearest river. A part of it is open for tourists, who go 20 metres (66 ft) down the steps in one shaft, have a ride in a boat, and go up the stairs in another shaft.
A "drift" is a more general term for any near-horizontal underground passage in a mine. Unlike an adit, a drift need not break out to the surface. Drift mining is the use of drifts to extract ore - in this case the drifts follow the vein.
A "level" is a horizontal passage that branches off from a shaft and is used for access to the parts of the mine where the ore is being removed. In mines where the lodes have significant vertical extent there can be many numbered levels, one below the other. They can be connected by short vertical shafts known as "winzes". A level that reaches the surface, on a hillside or in a valley, for instance, is called an "adit level". In the Worsley Navigable Levels in Greater Manchester, England, the levels were intentionally flooded and coal was transported on canal boats.
^ Thrush, Paul W., ed. (1968). "stulm". A Dictionary of Mining, Mineral, and Related Terms. United States Bureau of Mines Special Publications. U.S. Department of the Interior: Bureau of Mines. p. 1094. Retrieved 22 June 2023. stulm. An approximately horizontal passageway into a mine; an adit.
^ Thrush, Paul W., ed. (1968). "adit". A Dictionary of Mining, Mineral, and Related Terms. United States Bureau of Mines Special Publications. U.S. Department of the Interior: Bureau of Mines. p. 12. Retrieved 22 June 2023. adit. [...] A horizontal or nearly horizontal passage driven from the surface for the working or unwatering of a mine.
^R. W. Raymond, 1881, Glossary of Mining and Metallurgical Terms, American Institute of Mining Engineers, p.3.
^"Environmental Risk and Impact Assessment: Proposed Changes to the Approved Project Land" (PDF). Victoria's Big Build. 24 April 2018. p. 7. Retrieved 2024-02-15.
^ ab. Mine-Explorer. Archived from the original on 2006-05-15. Retrieved 2010-12-06.
Sourcesedit
Wikimedia Commons has media related to Adits.
Earl, Bryan (1994). Cornish Mining: The Techniques of Metal Mining in the West of England, Past and Present (2nd ed.). St Austell: Cornish Hillside Publications. ISBN0-9519419-3-3.
January 01, 1970
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For the ADIT see Advanced Diploma in International Taxation For the Indonesian animated series see Adit Sopo Jarwo An adit from Latin aditus entrance 1 or stulm 2 is a horizontal or nearly horizontal passage to an underground mine 3 Miners can use adits for access drainage 4 ventilation and extracting minerals at the lowest convenient level 1 Adits are also used to explore for mineral veins 1 Although most strongly associated with mining the term adit is sometimes also used in the context of underground excavation for non mining purposes for example to refer to smaller underground passageways excavated for underground metro systems to provide pedestrian access to stations pedestrian adits and for access required during construction construction adits 5 Gated entrance of an abandoned adit near Medford Oregon United States Look up adit in Wiktionary the free dictionary Contents 1 Construction 2 Access and ventilation 3 Drainage 4 Notable examples 5 Similar terms 6 See also 7 References 8 SourcesConstruction edit nbsp Queen Louise adit Zabrze Poland Adits are driven into the side of a hill or mountain and are often used when an ore body is located inside the mountain but above the adjacent valley floor or coastal plain In cases where the mineral vein outcrops at the surface the adit may follow the lode or vein until it is worked out in which case the adit is rarely straight The use of adits for the extraction of ore is generally called drift mining Adits can only be driven into a mine where the local topography permits There will be no opportunity to drive an adit to a mine situated on a large flat plain for instance Also if the ground is weak the cost of shoring up a long adit may outweigh its possible advantages Access and ventilation edit nbsp Horse adit in the abandoned lead mine Nenthead County Durham UK Access to a mine by adit has many advantages over the vertical access shafts used in shaft mining Less energy is required to transport miners and heavy equipment into and out of the mine It is also much easier to bring ore or coal out of the mine Horizontal travel by means of narrow gauge tramway or cable car is also much safer and can move more people and ore than vertical elevators In the past horses and pit ponies were used In combination with shafts adits form an important element in the ventilation of a mine in simple terms cool air will enter through an adit be warmed by the higher temperature underground and will naturally exhaust from vertical shafts some of which are sunk specifically for this purpose 6 Drainage edit nbsp Two Brothers Adit a small surviving mine entrance at the site of Eylesbarrow mine Dartmoor Devon Most adits are designed to slope slightly upwards from the entrance so that water will flow freely out of the mine 7 Mines that have adits can be at least partly drained of water by gravity alone or power assisted gravity The depth to which a mine can be drained by gravity alone is defined by the deepest open adit which is known as the drainage adit 8 The term mine drainage tunnel is also common at least in the United States Workings above this level known as above adit will remain unflooded as long as the adit does not become blocked All mine workings below both the drainage adit below adit and the water table will flood unless mechanical means are used for drainage Until the invention of the steam engine this was the main restriction on deep mining Adits are useful for deeper mines Water only needs to be raised to the drainage adit rather than to the surface Because of the great reduction in ongoing costs that a drainage adit can provide they have sometimes been driven for great distances for this purpose One example is the Milwr tunnel in North Wales which is about ten miles 16 km long Other examples are the Great County Adit in Cornwall a 40 mile 64 km long network of adits that used to drain the whole Gwennap mining area and the 3 9 miles 6 3 km Sutro Tunnel at the Comstock Lode in Virginia City Nevada A side benefit of driving such extensive adits is that previously unknown ore bodies can be discovered helping finance the enormous cost 8 Adits were used in Cornwall before 1500 and were important to the tin and copper mines in Cornwall and Devon because the ore bearing veins are nearly vertical thus acting as ingress channels for water 7 Notable examples editThis section does not cite any sources Please help improve this section by adding citations to reliable sources Unsourced material may be challenged and removed November 2021 Learn how and when to remove this message Great County Adit a system of over 40 miles 65 km of adits used for dewatering more than 100 mines in the Gwennap area of Cornwall in the 18th and early 19th centuries The Hollingwood Common Canal is a disused navigable coal mine adit which terminated at the Chesterfield Canal at Hollingwood near Staveley Derbyshire Milwr tunnel a 10 mile long 16 km drainage adit in North Wales Started in 1897 it still discharges an average of 87 million litres 23 million US gallons of water per day from the disused Halkyn District United Mines The Snowy Mountains hydroelectric and irrigation scheme in the Australian Snowy Mountains created during its construction The adits are very large and used to access the central point from which the hydro tunnels were constructed Black Trout Adit in Tarnowskie Gory Poland Part of a former silver mine the adit was used for removing water from the mine It still carries water from old galleries to the nearest river A part of it is open for tourists who go 20 metres 66 ft down the steps in one shaft have a ride in a boat and go up the stairs in another shaft Blue Hawk Mine near Kelowna British Columbia Canada NORCAT s Underground Mine Centre Fecunis Adit in Onaping Ontario Canada used for underground training and mining technology development Sutro Tunnel for drainage and exploitation of the Comstock Lode in Nevada Similar terms editThis section does not cite any sources Please help improve this section by adding citations to reliable sources Unsourced material may be challenged and removed November 2021 Learn how and when to remove this message A drift is a more general term for any near horizontal underground passage in a mine Unlike an adit a drift need not break out to the surface Drift mining is the use of drifts to extract ore in this case the drifts follow the vein A level is a horizontal passage that branches off from a shaft and is used for access to the parts of the mine where the ore is being removed In mines where the lodes have significant vertical extent there can be many numbered levels one below the other They can be connected by short vertical shafts known as winzes A level that reaches the surface on a hillside or in a valley for instance is called an adit level In the Worsley Navigable Levels in Greater Manchester England the levels were intentionally flooded and coal was transported on canal boats Sough is a term mainly used in the lead mining areas of Derbyshire The main purpose of a sough is to drain water from the mine See also editGlossary of coal mining terminology Mine capsReferences edit a b c Ripley George Dana Charles A eds 1879 Adit The American Cyclopaedia Thrush Paul W ed 1968 stulm A Dictionary of Mining Mineral and Related Terms United States Bureau of Mines Special Publications U S Department of the Interior Bureau of Mines p 1094 Retrieved 22 June 2023 stulm An approximately horizontal passageway into a mine an adit Thrush Paul W ed 1968 adit A Dictionary of Mining Mineral and Related Terms United States Bureau of Mines Special Publications U S Department of the Interior Bureau of Mines p 12 Retrieved 22 June 2023 adit A horizontal or nearly horizontal passage driven from the surface for the working or unwatering of a mine R W Raymond 1881 Glossary of Mining and Metallurgical Terms American Institute of Mining Engineers p 3 Environmental Risk and Impact Assessment Proposed Changes to the Approved Project Land PDF Victoria s Big Build 24 April 2018 p 7 Retrieved 2024 02 15 Earl 1994 pp 64 65 a b Earl 1994 p 36 a b Mining Encyclopaedia Adit Drainage Adit Deep Drainage Mine Explorer Archived from the original on 2006 05 15 Retrieved 2010 12 06 Sources edit nbsp Wikimedia Commons has media related to Adits Earl Bryan 1994 Cornish Mining The Techniques of Metal Mining in the West of England Past and Present 2nd ed St Austell Cornish Hillside Publications ISBN 0 9519419 3 3 Retrieved from https en wikipedia org w index php title Adit amp oldid 1219624336, wikipedia, wiki, book, books, library,
