Australia the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania and numerous smaller islands. It is the world's sixth-largest country by total area; the neighbouring countries are Papua New Guinea and East Timor to the north. The population of 25 million is urbanised and concentrated on the eastern seaboard. Australia's capital is Canberra, its largest city is Sydney; the country's other major metropolitan areas are Melbourne, Brisbane and Adelaide. Australia was inhabited by indigenous Australians for about 60,000 years before the first British settlement in the late 18th century, it is documented. After the European exploration of the continent by Dutch explorers in 1606, who named it New Holland, Australia's eastern half was claimed by Great Britain in 1770 and settled through penal transportation to the colony of New South Wales from 26 January 1788, a date which became Australia's national day; the population grew in subsequent decades, by the 1850s most of the continent had been explored and an additional five self-governing crown colonies established.
On 1 January 1901, the six colonies federated. Australia has since maintained a stable liberal democratic political system that functions as a federal parliamentary constitutional monarchy, comprising six states and ten territories. Being the oldest and driest inhabited continent, with the least fertile soils, Australia has a landmass of 7,617,930 square kilometres. A megadiverse country, its size gives it a wide variety of landscapes, with deserts in the centre, tropical rainforests in the north-east and mountain ranges in the south-east. A gold rush began in Australia in the early 1850s, its population density, 2.8 inhabitants per square kilometre, remains among the lowest in the world. Australia generates its income from various sources including mining-related exports, telecommunications and manufacturing. Indigenous Australian rock art is the oldest and richest in the world, dating as far back as 60,000 years and spread across hundreds of thousands of sites. Australia is a developed country, with the world's 14th-largest economy.
It has a high-income economy, with the world's tenth-highest per capita income. It is a regional power, has the world's 13th-highest military expenditure. Australia has the world's ninth-largest immigrant population, with immigrants accounting for 26% of the population. Having the third-highest human development index and the eighth-highest ranked democracy globally, the country ranks in quality of life, education, economic freedom, civil liberties and political rights, with all its major cities faring well in global comparative livability surveys. Australia is a member of the United Nations, G20, Commonwealth of Nations, ANZUS, Organisation for Economic Co-operation and Development, World Trade Organization, Asia-Pacific Economic Cooperation, Pacific Islands Forum and the ASEAN Plus Six mechanism; the name Australia is derived from the Latin Terra Australis, a name used for a hypothetical continent in the Southern Hemisphere since ancient times. When Europeans first began visiting and mapping Australia in the 17th century, the name Terra Australis was applied to the new territories.
Until the early 19th century, Australia was best known as "New Holland", a name first applied by the Dutch explorer Abel Tasman in 1644 and subsequently anglicised. Terra Australis still saw occasional usage, such as in scientific texts; the name Australia was popularised by the explorer Matthew Flinders, who said it was "more agreeable to the ear, an assimilation to the names of the other great portions of the earth". The first time that Australia appears to have been used was in April 1817, when Governor Lachlan Macquarie acknowledged the receipt of Flinders' charts of Australia from Lord Bathurst. In December 1817, Macquarie recommended to the Colonial Office. In 1824, the Admiralty agreed that the continent should be known by that name; the first official published use of the new name came with the publication in 1830 of The Australia Directory by the Hydrographic Office. Colloquial names for Australia include "Oz" and "the Land Down Under". Other epithets include "the Great Southern Land", "the Lucky Country", "the Sunburnt Country", "the Wide Brown Land".
The latter two both derive from Dorothea Mackellar's 1908 poem "My Country". Human habitation of the Australian continent is estimated to have begun around 65,000 to 70,000 years ago, with the migration of people by land bridges and short sea-crossings from what is now Southeast Asia; these first inhabitants were the ancestors of modern Indigenous Australians. Aboriginal Australian culture is one of the oldest continual civilisations on earth. At the time of first European contact, most Indigenous Australians were hunter-gatherers with complex economies and societies. Recent archaeological finds suggest. Indigenous Australians have an oral culture with spiritual values based on reverence for the land and a belief in the Dreamtime; the Torres Strait Islanders, ethnically Melanesian, obtained their livelihood from seasonal horticulture and the resources of their reefs and seas. The northern coasts and waters of Australia were visited s
Gotthard Base Tunnel
The Gotthard Base Tunnel is a railway tunnel through the Alps in Switzerland. It opened on 1 June 2016, full service began on 11 December 2016. With a route length of 57.09 km, it is the world's longest railway and deepest traffic tunnel and the first flat, low-level route through the Alps. It lies at the heart of the Gotthard axis and constitutes the third tunnel connecting the cantons of Uri and Ticino, after the Gotthard Tunnel and the Gotthard Road Tunnel; the link consists of two single-track tunnels connecting Erstfeld with Bodio and passing below Sedrun. It is part of the New Railway Link through the Alps project, which includes the Ceneri Base Tunnel further south and the Lötschberg Base Tunnel on the other main north-south axis, it is referred to as a "base tunnel" since it bypasses most of the existing Gotthard railway line, a winding mountain route opened in 1882 across the Saint-Gotthard Massif, operating at its capacity before the opening of the GBT. The new base tunnel establishes a direct route usable by high-speed rail and heavy freight trains.
The main purpose of the Gotthard Base Tunnel is to increase local transport capacity through the Alpine barrier for freight, notably on the Rotterdam–Basel–Genoa corridor, more to shift freight volumes from trucks to freight trains. This both reduces the danger of fatal road crashes involving trucks, reduces the environmental damage caused by heavy trucks; the tunnel provides a faster connection between the canton of Ticino and the rest of Switzerland, as well as between northern and southern Europe, cutting the Basel/Zürich–Lugano–Milan journey time for passenger trains by one hour. After 64 percent of Swiss voters accepted the NRLA project in a 1992 referendum, first preparatory and exploratory work began in 1996; the official start of construction began on 4 November 1999 at Amsteg. Drilling operations in the eastern tunnel were completed on 15 October 2010 in a breakthrough ceremony broadcast live on Swiss TV, in the western tunnel on 23 March 2011; the tunnel's constructor, AlpTransit Gotthard AG planned to hand over the tunnel to Swiss Federal Railways in operating condition in December 2016 but, on 4 February 2014, the handover date was changed to 5 June 2016 with the start of an 850-day opening countdown calendar on the AlpTransit homepage.
As of 1998, the total projected cost of the project was CHF 6.323 billion. Nine people died during construction; the Gotthard Base Tunnel, with a length of 57.09 kilometres and a total of 151.84 km of tunnels and passages, is the longest railway tunnel in the world, with a geodetic distance of 55.782 kilometres between the two portals. It is the first flat route through the Alps or any other major mountain range, with a maximum height of 549 metres above sea level, corresponding to that of Berne, it is the deepest railway tunnel in the world, with a maximum depth of 2,450 metres, comparable to that of the deepest mines on Earth. Without ventilation, the temperature inside the mountain reaches 46 °C. Like the two other tunnels passing below the Gotthard, the Gotthard Base Tunnel connects two Alpine valleys across the Saint-Gotthard Massif: the Urner Reusstal in the canton of Uri, in which flows the river Reuss, the Valle Leventina, the largest valley in the canton of Ticino, in which the river Ticino flows.
Unlike most other tunnels, the Gotthard Base Tunnel passes under several distinct mountain massifs, two of them being major subranges of the Alps, the Glarus Alps and the Saint-Gotthard Massif, with the valley of the Anterior Rhine, the Surselva in the canton of Graubünden, between them. The tunnel passes under these two ranges more than two kilometres below the Chrüzlistock and the Piz Vatgira. While the cantons of Uri and Ticino are part of the German- and Italian-speaking areas of Switzerland the Surselva is Romansh-speaking; the Alps influence the European climate – and that of Switzerland in particular – and there can be different weather conditions at each end of the GBT, described by the Ticinese architect Mario Botta: "The light changes at the Gotthard: that of the Mediterranean Sea is not the same as that of the continent, that of the central lands, that of Europe far away from the sea." On average, the temperature is 2 to 3 °C higher on the south side than the north side, but on some days, temperature differences are well over 10 °C.
The north portal lies in the north of the municipality of Erstfeld at an elevation of 460 metres, east of the Reuss. There, the tunnel penetrates the western slopes of the Bälmeten and Chli Windgällen before passing below the valley of the Chärstelenbach, a creek in the Maderanertal. From there, the tunnel runs parallel below the Witenalpstock; the main crest of the Glarus Alps, the watershed between the Reuss and the Anterior Rhine, is crossed below the Chrüzlistock, the crest having an elevation of about 2,700 metres at this point. From the crest and border, the tunnel runs parallel to the small valley of the river Strem before passing below Sedrun and the Anterior Rhine. From the bottom of the valley, the tunnel proceeds towards the valley of the Rein da Nalps and passes east of Lai da Nalps, before crossing the Gannar
The Cascade Tunnel refers to two railroad tunnels in the northwest United States, east of the Seattle metropolitan area in the Cascade Range of Washington, at Stevens Pass. It is 65 miles east of Everett, with both portals adjacent to U. S. Route 2. Both single-track tunnels were constructed by the Great Northern Railway; the first was 2.63 miles in length and opened in 1900 to avoid problems caused by heavy winter snowfalls on the original line that had eight zig zags. The current tunnel is a 7.8 miles in length and entered service in early 1929 1.5 miles south of and 500 feet lower in elevation than the original. The present east portal is nearly four miles east of the original's and is at 2,881 feet above sea level, 1,180 feet below the pass; the tunnel connects Berne in Chelan County on its east with Scenic Hot Springs in King County on its west and is the longest railroad tunnel in the United States. The first tunnel began construction on August 20, 1897, was completed on December 20, 1900.
The tunnel was 2.6 miles long. John Frank Stevens was the principal engineer on the interim switchback route and the first Cascade Tunnel. Stevens Pass, located above the tunnels, was named after him; the tunnel had a fume problem from the coal-burning steam locomotives. It was built with a 1.7% gradient eastbound, too close to the ruling gradient of 2.2%. Because of the steepness of the line, the locomotives had to pull hard to make the grade and thus burn more coal, which would lead to immense smoke in the bore; the tunnel was electrified, with the project completed on July 1909, eliminating the problem. The unusual system used was three-phase AC, 6600 volts at 25 Hz, from a 5 MW hydroelectric plant on the Wenatchee River just west of Leavenworth; the tunnel section only was electrified. The motive power for the section consisted of four GN boxcab locomotives supplied by the American Locomotive Company. Three locomotives were coupled together and hauled trains at a constant speed of 15.7 mph, but when larger trains required four locomotives the motors were concatenated, so that the speed was halved to 7.8 mph to avoid overloading the power supply.
The consulting engineer, Cary T. Hutchinson, published a detailed description of the system in 1909; the tunnel was still plagued by snow slides in the area. On March 1, 1910, an avalanche at Wellington, near the west portal of the original 2.6 miles Cascade Tunnel, killed 96-101 people, the deadliest avalanche disaster in U. S. history. This disaster prompted the construction of the current tunnel; the old tunnel was abandoned in 1929, after the new lower tunnel was opened. During the winter of 2007–2008, a section of the roof caved in and created a debris dam inside the tunnel, making it impassable to pedestrians due to standing water and ceiling debris. A warning was issued to stay clear of the western side of the old tunnel for a distance of one-half mile for the indeterminate future; the new Cascade Tunnel was opened on January 12, 1929. The new line had 93.2 track miles electrified, between Skykomish and Wenatchee. The ruling grade was still 2.2 percent, although 21 miles of 2 percent or worse grade was eliminated.
The line length was reduced by 8.7 miles, maximum elevation was lowered by 502 feet from 3,382 feet to 2,881 feet. The new tunnel was started in December 1925, was built in just over three years by A. Guthrie of St. Paul, Minnesota. Project manager and engineer Frederick Mears was assigned to make sure. While the new tunnel was being constructed, the Great Northern received delivery of five new electric locomotives; the new locomotives had a motor-generator supplying DC traction motors, the single-phase AC supply required only one instead of two overhead conductors. Hence, the Great Northern re-electrified 21 miles of the original route at single-phase AC, including 8 miles that were subsequently abandoned upon completion of the new tunnel, used steam locomotives on the short remaining stretches of the old line. On March 5, 1927, the three-phase electrification was abandoned, the new locomotives were placed in service between Skykomish and the east portal of the old tunnel. Furthermore, for the first time regenerated power could be used by another train or fed back to the utility company.
Two years the new tunnel opened. It was the longest railroad tunnel in the Americas until 1989, when the Mount Macdonald Tunnel in British Columbia was completed, moving the Cascade into second place. Electrification was removed in 1956, after a ventilation system was installed to eliminate diesel fumes. On April 4, 1996 an eastbound freight train broke through the doors at the east portal after they did not open properly. There were no injuries, but the broken doors slowed operations for a couple of days while replacement doors were brought up from the Seattle area. In Fall 2001 a single car was dragged the rest of the way out, it ripped out wirin
South Africa the Republic of South Africa, is the southernmost country in Africa. It is bounded to the south by 2,798 kilometres of coastline of Southern Africa stretching along the South Atlantic and Indian Oceans. South Africa is the largest country in Southern Africa and the 25th-largest country in the world by land area and, with over 57 million people, is the world's 24th-most populous nation, it is the southernmost country on the mainland of the Eastern Hemisphere. About 80 percent of South Africans are of Sub-Saharan African ancestry, divided among a variety of ethnic groups speaking different African languages, nine of which have official status; the remaining population consists of Africa's largest communities of European and multiracial ancestry. South Africa is a multiethnic society encompassing a wide variety of cultures and religions, its pluralistic makeup is reflected in the constitution's recognition of 11 official languages, the fourth highest number in the world. Two of these languages are of European origin: Afrikaans developed from Dutch and serves as the first language of most coloured and white South Africans.
The country is one of the few in Africa never to have had a coup d'état, regular elections have been held for a century. However, the vast majority of black South Africans were not enfranchised until 1994. During the 20th century, the black majority sought to recover its rights from the dominant white minority, with this struggle playing a large role in the country's recent history and politics; the National Party imposed apartheid in 1948. After a long and sometimes violent struggle by the African National Congress and other anti-apartheid activists both inside and outside the country, the repeal of discriminatory laws began in 1990. Since 1994, all ethnic and linguistic groups have held political representation in the country's liberal democracy, which comprises a parliamentary republic and nine provinces. South Africa is referred to as the "rainbow nation" to describe the country's multicultural diversity in the wake of apartheid; the World Bank classifies South Africa as an upper-middle-income economy, a newly industrialised country.
Its economy is the second-largest in Africa, the 34th-largest in the world. In terms of purchasing power parity, South Africa has the seventh-highest per capita income in Africa; however and inequality remain widespread, with about a quarter of the population unemployed and living on less than US$1.25 a day. South Africa has been identified as a middle power in international affairs, maintains significant regional influence; the name "South Africa" is derived from the country's geographic location at the southern tip of Africa. Upon formation, the country was named the Union of South Africa in English, reflecting its origin from the unification of four separate British colonies. Since 1961, the long form name in English has been the "Republic of South Africa". In Dutch, the country was named Republiek van Zuid-Afrika, replaced in 1983 by the Afrikaans Republiek van Suid-Afrika. Since 1994, the Republic has had an official name in each of its 11 official languages. Mzansi, derived from the Xhosa noun umzantsi meaning "south", is a colloquial name for South Africa, while some Pan-Africanist political parties prefer the term "Azania".
South Africa contains human-fossil sites in the world. Archaeologists have recovered extensive fossil remains from a series of caves in Gauteng Province; the area, a UNESCO World Heritage site, has been branded "the Cradle of Humankind". The sites include one of the richest sites for hominin fossils in the world. Other sites include Gondolin Cave Kromdraai, Coopers Cave and Malapa. Raymond Dart identified the first hominin fossil discovered in Africa, the Taung Child in 1924. Further hominin remains have come from the sites of Makapansgat in Limpopo Province and Florisbad in the Free State Province, Border Cave in KwaZulu-Natal Province, Klasies River Mouth in Eastern Cape Province and Pinnacle Point and Die Kelders Cave in Western Cape Province; these finds suggest that various hominid species existed in South Africa from about three million years ago, starting with Australopithecus africanus. There followed species including Australopithecus sediba, Homo ergaster, Homo erectus, Homo rhodesiensis, Homo helmei, Homo naledi and modern humans.
Modern humans have inhabited Southern Africa for at least 170,000 years. Various researchers have located pebble tools within the Vaal River valley. Settlements of Bantu-speaking peoples, who were iron-using agriculturists and herdsmen, were present south of the Limpopo River by the 4th or 5th century CE, they displaced and absorbed the original Khoisan speakers, the Khoikhoi and San peoples. The Bantu moved south; the earliest ironworks in modern-day KwaZulu-Natal Province are believed to date from around 1050. The southernmost group was the Xhosa people, whose language incorporates certain linguistic traits from the earlier Khoisan people; the Xhosa reached the Great Fish River, in today's Eastern Cape Province. As they migrated, these larger Iron Age populations
Lötschberg Base Tunnel
The Lötschberg Base Tunnel is a 34.57-kilometre railway base tunnel on the BLS AG's Lötschberg line cutting through the Bernese Alps of Switzerland some 400 m below the existing Lötschberg Tunnel. It runs between Frutigen and Raron, was built as one of the two centerpieces of the NRLA project. Breakthrough was in April 2005 and construction ended in 2006; the opening ceremony was in June 2007 Full scale operation began in December 2007, the link is saturated because a single-track section reduces its capacity. Built to ease lorry traffic on Swiss roads, the LBT allows an increased number of lorries and trailers to be loaded onto trains in Germany, pass through Switzerland on rail and be unloaded in Italy, it cuts down travel time for German tourists going to Swiss ski resorts and puts the Valais into commuting distance to Bern by reducing travel time by 50%. The total cost was SFr 4.3 billion. This and the Gotthard Base Tunnel are the two centerpieces of the Swiss NRLA project. Track construction in the LBT was completed in July 2006.
Extensive testing took place, including more than 1,000 test runs, which focused among other things on the use of the ETCS Level 2 system. For the second half of 2007, only regular freight used the LBT, plus some international and InterCity passenger trains. Since February 2008, the LBT has been used for normal InterCity routes. Travel time between Visp and Spiez is about 28 minutes. Due to the soaring costs of the overall NRLA project, funds were diverted from the Lötschberg tunnel to the Gotthard Base Tunnel; the complete LBT will consist of two single track bores side by side from portal to portal, connected about every 300 m with cross cuts, enabling the other tunnel to be used for escape. From South to North a third of the tunnel is double track, a third is single track with the second bore in place but not equipped, a third is only a single track tunnel with the parallel exploration adit providing the emergency egress; the construction was divided into 3 phases with only phase 1 completed to date: Phase 1: construction of about 75% of the length of the West tube and the complete East tube of the main tunnel, the Engstlige tunnel, the two bridges across the Rhône, the branch bore from Steg.
Tracks are laid in the Eastern tubes of the LBT and Engstlige tunnels, for some 12 km in the western tube of LBT, starting from the South. Phase 2: laying of tracks in the bored but not equipped part of the western tube of LBT, in the western tube of Engstlige tunnel. Phase 3: construction of the remaining 8 km of the western tube, laying tracks on the Steg branch, connection of this branch to the main line Brig-Lausanne, but towards Lausanne. Phases 2 and 3 may be done together. Completing the LBT is estimated to cost 1 billion Swiss francs; the project includes two parallel bridges over the river Rhône in canton Valais, the 2.6 km Engstlige tunnel. A planning contract for phases 2 and 3 was awarded in 2016. About 110 trains per day use the LBT, 66 have to use the old mountain tunnel because the single track section limits the capacity of the base tunnel. Of the 110, 30 are passenger and 80 are freight, including both intermodal freight transport and long-distance heavy freight trains. Heavy freight trains up to a maximum weight of 4,000 tons and a maximum length of 1,500 metres have to use the LBT, as they cannot use the existing mountain track.
The 21 km of single track without passing loops complicate operations, trains are scheduled by batches in each direction separated by long intervals. Regular freight trains: 100 km/h Qualified freight trains: 160 km/h Passenger trains: 200 km/h Tilting passenger trains: 250 km/h The warmth of the water flowing out of the tunnel is used to heat the Tropenhaus Frutigen, a tropical greenhouse producing exotic fruit, sturgeon meat and caviar. Lötschberg Lötschberg Tunnel Simplon Tunnel NRLA List of longest tunnels List of tunnels by location Official project site Official site of the "ARGE Bahntechnik Lötschberg" the general contractor for the railway technology Alptransit Portal of the Swiss Federal Archives Site with a movie documentation about the engineering and the works MSNBC report on the tunnel breakthrough, 28 April 2005 Rail Technology in the Lötschberg Base Tunnel Image Gallery on a contractors site
Blue Ridge Tunnel
The Blue Ridge Tunnel is a historic railroad tunnel built during the construction of the Blue Ridge Railroad in the 1850s. The tunnel was the westernmost and longest of four tunnels engineered by Claudius Crozet to cross the Blue Ridge Mountains at Rockfish Gap in central Virginia. At 4,237 feet in length, the tunnel was the longest tunnel in the United States at the time of its completion in 1858; the tunnel was used by the Virginia Central Railroad from its opening to 1868, when the line was reorganized as the Chesapeake and Ohio Railroad. The Chesapeake and Ohio routed trains through the tunnel until it was abandoned and replaced by a new tunnel in 1944; the new tunnel was named the "Blue Ridge Tunnel" as well, although the original tunnel still remains abandoned nearby. The old Blue Ridge Tunnel has since been named a Historic Civil Engineering Landmark; the Blue Ridge Railroad was incorporated by the Commonwealth of Virginia in 1849 with Claudius Crozet as chief engineer. Its purpose was to provide a crossing of the Blue Ridge Mountains for the Virginia Central Railroad into the Shenandoah Valley.
The Virginia Board of Public Works, founded in 1816, supported numerous internal improvements in the state, owning part of the Virginia Central in stock as well as all of the Blue Ridge Railroad. A civil engineer of considerable skill, Crozet had identified the eventual route as early as 1839. Rail service reached Charlottesville by 1851. To protect its investment and enable transportation, the State incorporated and financed the Blue Ridge Railroad to accomplish the hard and expensive task of crossing the Blue Ridge mountain barrier to the west. Rather than attempting the more formidable Swift Run Gap, the state-owned Blue Ridge Railroad built over the mountains at the next major gap to the south, Rockfish Gap near Afton Mountain. Overseen by Crozet, the crossing was accomplished by building four tunnels, including the 4,273-foot Blue Ridge Tunnel near the top of the pass. With construction proceeding from either side a decade before the invention of dynamite, the complex was dug though solid granite with only hand drills and black powder.
The tunnel was less than 6 inches off perfect alignment when it was holed through on December 29, 1856. When completed, the Blue Ridge Tunnel was the longest in the United States and one of the longest tunnels in the world, a remarkable feat of engineering, it opened to rail traffic in April 1858, was considered to be one of the engineering wonders of the modern world. During the American Civil War, the infantry under Confederate General Stonewall Jackson earned the nickname "foot cavalry" by traveling quickly across the Blue Ridge Mountains, to the consternation of the Union leaders opposing them. To do this, Jackson used his detailed knowledge of the gaps in the Blue Ridge and utilized the Blue Ridge Tunnel as a passageway for his troops; the Blue Ridge Railroad ceased to exist once the route across the mountains was completed, becoming a part of the Virginia Central Railroad. In 1868 the Virginia Central was merged with another state-chartered railroad, the Covington and Ohio Railroad, to create the Chesapeake and Ohio Railroad.
This helped achieve Virginia's long-term goal of linking its navigable rivers of the Chesapeake Bay watershed with the Ohio River. The C&O Railroad was subsequently sold to Collis Potter Huntington; the C&O replaced the Blue Ridge Tunnel in 1944 with a larger, parallel tunnel to accommodate increased rail traffic of World War II materiel. The new tunnel -, 4 feet off alignment when constructed - is now referred to as the Blue Ridge Tunnel, it is still in use by the Buckingham Branch Railroad and Amtrak. After the original tunnel was replaced, it became known as the Crozet Tunnel in honor of its remarkable engineer, for whom the nearby town of Crozet is named, it is planned to be used as part of a rail trail project. The Claudius Crozet Blue Ridge Tunnel Foundation secured a $749,000 grant through the Virginia Department of Transportation and the Commonwealth Transportation Board to begin Phase I of the project to reopen the long-closed tunnel with a bike path and hiking trail. Phase I will be a footpath from the former Afton rail depot to a concrete bulwark 700 feet into the tunnel.
The first piece of the trail will begin and end on the east side of Afton Mountain."This is safe where we're going," district supervisor Allen Hale said. "But once you get to the tunnel and someone walks through here and gets all the way up, they're going to want to go in... The ultimate goal … is to have the tunnel open all the way through to the west side to the Blue Ridge Mountains and have a trail connection to U. S. Route 250 on the other side," Hale said... According to The News & Advance archives, the $450,000 required for Phase II has been raised. Hale hopes to begin Phase II some time this year; the date for Phase III has yet to be set. In the fall of 2017, a University of Virginia assistant professor and two graduate students used a ground-based autonomous robot to scan and map the tunnel using LiDAR; the result was a three-dimensional map of the tunnel which can be used for restoration or construction projects in the future. Brookville Tunnel Greenwood Tunnel Kingwood Tunnel, the Blue Ridge Tunnel's predecessor as longest tunnel in the United States Dixon, Thomas W. Jr..
"A Short History of the Chesapeake & Ohio Railway Mountain Subdivision". Clifton Forge, Virginia: Chesapeake and Ohio Historical Society. Drinker, Henry Sturgis. Tunneling, explosive compounds, rock drills. John Wiley
Tunnel boring machine
A tunnel boring machine known as a "mole", is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. They may be used for microtunneling, they can bore through anything from hard rock to sand. Tunnel diameters can range from one metre to 17.6 metres to date. Tunnels of less than a metre or so in diameter are done using trenchless construction methods or horizontal directional drilling rather than TBMs. Tunnel boring machines are used as an alternative to drilling and blasting methods in rock and conventional "hand mining" in soil. TBMs have the advantages of limiting the disturbance to the surrounding ground and producing a smooth tunnel wall; this reduces the cost of lining the tunnel, makes them suitable to use in urbanized areas. The major disadvantage is the upfront cost. TBMs are expensive to construct, can be difficult to transport; the longer the tunnel, the less the relative cost of tunnel boring machines versus drill and blast methods.
This is because tunneling with TBMs is much more efficient and results in shortened completion times, assuming they operate successfully. Drilling and Blasting however remains the preferred method when working through fractured and sheared rock layers; the first successful tunnelling shield was developed by Sir Marc Isambard Brunel to excavate the Thames Tunnel in 1825. However, this was only the invention of the shield concept and did not involve the construction of a complete tunnel boring machine, the digging still having to be accomplished by the standard excavation methods; the first boring machine reported to have been built was Henri-Joseph Maus's Mountain Slicer. Commissioned by the King of Sardinia in 1845 to dig the Fréjus Rail Tunnel between France and Italy through the Alps, Maus had it built in 1846 in an arms factory near Turin, it consisted of more than 100 percussion drills mounted in the front of a locomotive-sized machine, mechanically power-driven from the entrance of the tunnel.
The Revolutions of 1848 affected the funding, the tunnel was not completed until 10 years by using less innovative and less expensive methods such as pneumatic drills. In the United States, the first boring machine to have been built was used in 1853 during the construction of the Hoosac Tunnel in northwest Massachusetts. Made of cast iron, it was known as Wilson's Patented Stone-Cutting Machine, after inventor Charles Wilson, it drilled 10 feet into the rock before breaking down. Wilson's machine anticipated modern TBMs in the sense that it employed cutting discs, like those of a disc harrow, which were attached to the rotating head of the machine. In contrast to traditional chiseling or drilling and blasting, this innovative method of removing rock relied on simple metal wheels to apply a transient high pressure that fractured the rock. In 1853, the American Ebenezer Talbot patented a TBM that employed Wilson's cutting discs, although they were mounted on rotating arms, which in turn were mounted on a rotating plate.
In the 1870s, John D. Brunton of England built a machine employing cutting discs that were mounted eccentrically on rotating plates, which in turn were mounted eccentrically on a rotating plate, so that the cutting discs would travel over all of the rock face, to be removed; the first TBM that tunneled a substantial distance was invented in 1863 and improved in 1875 by British Army officer Major Frederick Edward Blackett Beaumont. In 1875, the French National Assembly approved the construction of a tunnel under the English Channel and the British Parliament allowed a trial run to be made; the cutting head of English's TBM consisted of a conical drill bit behind which were a pair of opposing arms on which were mounted cutting discs. From June 1882 to March 1883, the machine tunneled, through chalk, a total of 6,036 feet. A French engineer, Alexandre Lavalley, a Suez Canal contractor, used a similar machine to drill 1,669 m from Sangatte on the French side. However, despite this success, the cross-Channel tunnel project was abandoned in 1883 after the British military raised fears that the tunnel might be used as an invasion route.
In 1883, this TBM was used to bore a railway ventilation tunnel — 7 feet in diameter and 6,750 feet long — between Birkenhead and Liverpool, through sandstone under the Mersey River. During the late 19th and early 20th century, inventors continued to design and test TBMs in response to the need for tunnels for railroads, sewers, water supplies, etc. TBMs employing rotating arrays of drills or hammers were patented. TBMs that resembled giant hole saws were proposed. Other TBMs consisted of a rotating drum with metal tines on its outer surface, or a rotating circular plate covered with teeth, or revolving belts covered with metal teeth. However, all of these TBMs proved expensive and unable to excavate hard rock. TBM development continued in potash and coal mines, where the rock was softer. A TBM with a bore diameter of 14.4 m was manufactured by The Robbins Company for Canada's Niagara Tunnel Project. The machine was used to bore a hydroelectric tunnel beneath Niagara Falls; the machine was named "Big Becky" in reference to the Sir Adam Beck hydroelectric dams to which it is tunneling to provide an additional hydroelectric tunnel.
An earth pressure balance TBM