An adit (from Latin aditus, entrance) is an entrance to an underground mine which is horizontal or nearly horizontal, by which the mine can be entered, drained of water, ventilated, and minerals extracted at the lowest convenient level. Adits are also used to explore for mineral veins.
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 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.
Most adits are designed to slope slightly upwards from the entrance so that water will flow freely out of the mine. 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". 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, as 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 (65 km)-long network of adits that used to drain the whole Gwennap mining area, and the 3.9 mile (6.2 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.
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.
8 x 10 Tasveer (English: 8 x 10 Picture) is a 2009 Indian supernatural psychological thriller film written and directed by Nagesh Kukunoor, and produced by Percept Picture Company, starring Akshay Kumar and Ayesha Takia Azmi. The film features Sharmila Tagore, Javed Jaffrey, Anant Mahadevan, Girish Karnad, Benjamin Gilani, Rushad Rana, Andrea Tully, and Pia Shah in supporting roles. In March 2008, the cast and crew filmed in Calgary, Alberta, Canada and a few parts were noticed to be the Western Cape of South Africa. It was previously called Tasveer, but changed due to the director's insistence that the title was jinxed. The film's music is composed by Salim-Sulaiman with a title track by Bohemia.A. D. Patel Institute of Technology
The A. D. Patel Institute of Technology (ADIT) is a degree engineering college established by in 2000 in affiliation with Gujarat Technological University under the management of Charutar Vidhya Mandal (CVM). The college has a 40-acre campus developed by CVM as New Vallabh Vidhyanagar.Adit Nunatak
Adit Nunatak (65°54′S 62°48′W) is an exposed area of land not covered with ice or snow 3 miles (5 km) west-northwest of Mount Alibi on the north side of Leppard Glacier, in Voden Heights on Oscar II Coast in Graham Land. Surveyed by Falkland Islands Dependencies Survey (FIDS) in 1955. Named adit (entrance) by United Kingdom Antarctic Place-Names Committee (UK-APC), because at the time (1957), it marked the approach to an unsurveyed inland area between Leppard Glacier and Flask Glacier.Asambhav
Asambhav (Hindi: असम्भव, translation: Impossible) is a 2004 Indian Hindi action thriller directed by Rajiv Rai and produced by Gulshan Rai under Trimurti Films banner. It was released on 23 July 2004, starring Arjun Rampal, Naseeruddin Shah and Priyanka Chopra in the lead roles with Dipannita Sharma, Tom Alter, Milind Gunaji and Sharat Saxena playing supporting roles among others. The film was shot entirely in Switzerland.Rajiv Rai worked with Arjun Rampal in Pyaar Ishq Aur Mohabbat (2001). Rai signed him for a second time for Asambhav in 2002. Work on the movie had begun in 2002 when he started his new project and titled it Asambhav. Aishwarya Rai was initially signed to act as Rampal's heroine but was replaced by Priyanka Chopra. Legendary actor Naseeruddin Shah was cast as the villain. Shooting began in June 2003 and was completed in September 2003. It was the first Indian film to be graded digitally on Luster.The film was launched in March 2004. The soundtrack was composed by Viju Shah; it was released on 26 May 2004. The film was released on 23 July 2004. Through an extensive post-production work and huge promotion, Asambhav was an average grosser at the box office, collecting ₹34 million (US$470,000) nett. It grossed ₹43.0 million (US$600,000) in India and was average overseas as well, with a collection of US$19,504 in the United States and £16,894 in the United Kingdom.Beer Quarry Caves
Beer Quarry Caves is a man-made limestone underground complex located about a mile west of the village of Beer, Devon, and the main source in England for beer stone. The underground tunnels resulted from 2,000 years of quarrying beer stone, which was particularly favoured for cathedral and church features such as door and window surrounds because of its colour and workability for carving. Stone from the quarry was used in the construction of several of southern England's ancient cathedrals and a number of other important buildings as well as for many town and village churches, and for some buildings in the United States. Extraction was particularly intense during the Middle Ages, but continued until the 1920s. An adit to another set of workings can be seen from the South West Coast Path east of Branscombe, having been exposed by a landslip in the late 18th century. The quarry is part of the Jurassic Coast, and is a Site of Special Scientific Interest (SSSI).Black Trout Adit
Black Trout Adit (Polish: Sztolnia Czarnego Pstrąga) is the longest (600 meters) underground tourist route in Poland travelled by boats. It's a part of one of 8 adits dug in the area to drain the workings. The Black Trout Adit is located in a park in the west of the town Tarnowskie Góry. Access is by two shafts Ewa and Sylwester (the traffic is alternating). The guide puts the boats in motion and tells the stories connected with the place.Carnon River
The Carnon River is a heavily polluted river in Cornwall, England. It starts in Chacewater. Trewedna Water and River Kennall flow into the Carnon before it merges with Tallack's Creek to become Restronguet Creek, which eventually flows into the English Channel at the mouth of Carrick Roads.The Nebra sky disc, a gold-decorated bronze disc found in Germany and dated to the Bronze Age contains both gold and tin from the Carnon valley.In 1992 the river was hit by a major pollution incident, when over 45 million litres of contaminated water from the closed Wheal Jane mine was released by the collapse of an adit, colouring the river water red. A treatment works has since been installed at Wheal Jane to intercept the contaminated water and treat it to remove suspended metals and restore a neutral pH.Conglog Slate Quarry
Conglog Slate Quarry was a small enterprise situated to the north-west of Tanygrisiau near Blaenau Ffestiniog in Wales. It was overshadowed by the much bigger Rhosydd Quarry a little further to the west. It was active from 1854 to 1910, and was operated by an individual, two partnerships and four separate companies over this period.Croesor Quarry
Croesor Quarry is a large underground slate mine in north Wales which was served by Croesor Tramway. Small scale quarrying began in the 1840s, and by 1861, there were two companies in operation. They amalgamated in 1865, a year after the quarry was connected to the newly opened Croesor Tramway. Much money was invested in development work, but volumes of useful slate produced were small, amounting to just 226 tons in 1868. Access to the underground workings was by a single adit, and the surface mill was powered by two water wheels. A change of ownership in 1875 did little to improve the profitability of the quarry, and it closed in 1878 or 1882.
In 1895, the quarry reopened under the direction of Moses Kellow, a fearless innovator who set about modernising working practices and methods. The two-man teams working in the mill were no longer tied to a two-man team working underground, which enabled the mill to operate more efficiently. Following trials with air drills, he decided instead to electrify the mill, building a large hydro-electric station, which generated three-phase alternating current, rather than the direct current recommended by British manufacturers. He obtained motors from Prague, which were used to drive winches and an electric locomotive, the first to work in Wales. The water wheels were supplemented by Pelton wheels, supplied by Gilbert Gilkes of Kendal. His greatest innovation was the Kellow drill, a hydraulic drill for which he obtained six patents between 1898 and 1915. It could drill a 7.5-foot (2.3 m) hole in the slate in under two minutes, much less than the day required using hand drills. The mine was ventilated by a Guibal fan, housed in a fan-house near the entrance to the adit. Peak output under Kellow's direction was between 5,000 and 6,000 tons per year, though it declined in the later years, until the quarry closed in 1930.
The chambers were used by Cookes Explosives to store propellants from the late 1940s until the early 1970s. This ceased when the Central Electricity Generating Board became aware of it, and feared that an underground explosion would damage the dams of the Ffestiniog pumped storage power station. Both lakes were drained until the explosives had been removed. The quarry was worked on seven levels, but the three below the adit level are now flooded. There was an underground link to the nearby Rhosydd Quarry, and the Croesor Rhosydd Through Trip is a well known, if somewhat dangerous, route for mine explorers.Dehorokkhi
Dehorokkhi (English: Bodyguard) is a Bangladeshi action film directed by Iftakar Chowdhury. The film was produced by Fatman Films. Dehorokkhi is an action based romantic triangle film. The film features Eamin Haque Bobby, Anisur Rahman Milon (Anti Hero), Kazi Maruf and Shiva Shanu. The film marks 55 years of Bangladeshi film industry. Dehorokkhi was released on 50 screens. The movie created a buzz through its trailer in social networking sites. The music was distributed by G-Series.Dhaka Attack
Dhaka Attack (Bengali: ঢাকা অ্যাটাক) is a Bangladeshi action thriller film produced by Dhaka Police Paribar Kallayan Samity Ltd., Three Wheelers Ltd. and Splash Multimedia. It features Arifin Shuvoo, Mahiya Mahi, Taskeen Rahman and ABM Sumon in lead roles. It was directed by Dipankar Sengupta and written by Sunny Sanwar. The film was distributed by Abhi Kothachitra and Swapna Scarecrow.Fatman Films
Fatman Films, is a music company and film production company of Bangladesh. The company was established in 2011 by musician Adit Ozbert. The company specializes in music production, film production and distribution.Great County Adit
The Great County Adit, sometimes called the County Adit, or the Great Adit was a system of interconnected adits that helped drain water from the tin and copper mines in the Gwennap area of Cornwall, in the United Kingdom. Construction started in 1748 and it eventually reached a length of over 40 miles (65 km) of underground tunnel, providing drainage to over 100 mines at an average depth of 80-100m.The adit was the brainchild of John Williams (born 1714) of Scorrier who was the manager of Poldice mine. Although work was started in 1748, it did not reach Poldice mine until the late 1760s. By 1778 the adit had been extended past Wheal Busy to Wheal Peevor, and another branch, known as the Consols Adit was driven west in the 1770s and 80s to drain the Consolidated Mines and United Mines. By 1792 a branch from Poldice extended to Wheal Unity.
The portal of the adit is in the Carnon Valley below the hamlet of Twelveheads. In 1839, probably at its peak, it discharged over 14.5 million gallons (66 million litres) of water per day into the Carnon River. At that time the adit had more steam engines pumping into it than were used by the whole of continental Europe and America combined.The Carnon River empties into Restronguet Creek (a tidal arm of the Carrick Roads upstream from Falmouth). Major floods in the winter of 1876 caused large quantities of gangue and silt to be washed into the higher part of Restronguet Creek, permanently damaging navigational access to the upper quays at Devoran.Although all the mines served by the Great County Adit have closed and it is unmaintained, it still drains many of their underground workings today; in the summer of 1980 the flow was 500,000 gallons per day.Historic Silver Mine in Tarnowskie Góry
The Historic Silver Mine, (Polish: Zabytkowa Kopalnia Srebra), is a mining museum in Tarnowskie Góry, in Silesia in Poland. The mine and the neighbouring Black Trout Adit are remnants of a silver mining industry. The museum is an Anchor point on the European Route of Industrial Heritage. It also joined The International Committee for the Conservation of the Industrial Heritage and the Silesian Tourist Organization.Lawson Adit
The Lawson Adit is a horizontal mine tunnel, or adit, on the UC Berkeley campus, near the Hearst Mining Building, dug directly through the Hayward Fault. Started in 1916, the adit is named after Andrew Lawson, one-time Dean of the College of Mining at UC Berkeley.Merantau
Merantau, released in some countries as Merantau Warrior, is a 2009 Indonesian martial arts action film written, directed and edited by Gareth Huw Evans, and starring Iko Uwais. The film, which marks Uwais' debut as an actor, is the first collaboration between director Evans and star Uwais. It also marks the acting debut of Yayan Ruhian, both of whom Evans met while shooting for a documentary in Indonesia which became his introduction to the Pencak Silat martial art.
The film showcases the Minangkabau tradition of "Merantau", a rite of passage where a man leaves his home to pursue a career or gain experience outside of the village, a culture where inheritance is largely matriarchal. It showcases Yuda who leaves his village in hopes of teaching Silat in Jakarta, only to be sidetracked as he attempts to save a girl from being kidnapped. The film showcases a style of Silat known as "Silek Harimau" (Tiger Silat). It also features actors Donny Alamsyah and Alex Abbad who, along with Uwais and Ruhiyan, would later appear in Evans' subsequent films in The Raid (2011) and The Raid 2 (2014).
Evans' first major feature film, Merantau premiered at the Puchon International Fantastic Film Festival in South Korea on 23 July 2009, before being released theatrically on 6 August in Indonesia. It won the Jury Award for Best Film at the inaugural 2010 ActionFest in North Carolina.Poldice mine
Poldice mine is a former metalliferous mine located in Poldice Valley in south-west Cornwall, England, United Kingdom. It is situated near the hamlet of Todpool, between the villages of Twelveheads and St Day, three miles (5 km) east of Redruth.Quincy and Torch Lake Cog Railway
The Quincy and Torch Lake Cog Railway is a half-mile long, 4 ft 8 1⁄2 in (1,435 mm) standard gauge cog railway in Hancock, Michigan. It opened in May 1997 to transport tourists to the adit entrance of the Quincy Mine's Number 5 shaft. Its tram car has a capacity of 28 people and travels at a maximum grade of 35%. It is one of only a few rack railways in the United States.Speedwell Cavern
The Speedwell Cavern is one of the four show caves in Castleton, Derbyshire, England.
It consists of a horizontal lead miners' adit (a level passageway driven horizontally into the hillside) leading to the cavern itself, a limestone cave. The adit is permanently flooded, resulting in Speedwell Cavern's (locally unique) feature: after descending a long staircase, the visitor makes the journey into the cave by boat. Originally the guide propelled the boat by pushing against the walls with his hands, later the boat was legged through, and now it is powered by an electric motor.
At the end of the adit, the visitor alights from the boat and walks into the cave to see the fluorspar veins, the stalactites and stalagmites, and the so-called "Bottomless Pit". This pit is an extremely deep vertical shaft, now choked to within 20 metres (66 ft) of the surface by rock spoil dumped by miners. The original depth of the shaft has been estimated, from the amount of spoil placed in the shaft over the years, at around 150 metres (490 ft).
A connection was discovered in 1999 between the Speedwell Cavern system and Titan, the largest natural shaft in the UK, which is 141.5 metres (464 ft) high.