The AMARC aka The Boneyard
309th Aerospace Maintenance and Regeneration Group
The 309th Aerospace Maintenance and Regeneration Group (AMARG), often called The Boneyard, is a United States Air Force aircraft storage and maintenance facility in Tucson, Arizona, located on Davis-Monthan Air Force Base. AMARG was previously Aerospace Maintenance and Regeneration Center, AMARC, and before that the Military Aircraft Storage and Disposal Center, MASDC.
It takes care of more than 4,400 aircraft, including 700 F-4 Phantom IIs, whose total original purchase price is estimated at $27 billion. An Air Force Materiel Command (formerly AFLC, Air Force Logistics Command) unit, the group is under the command of the 309th Maintenance Wing of Hill Air Force Base, Utah. AMARG was originally meant to store excess Department of Defense and Coast Guard aircraft, but has in recent years been designated the sole repository of out-of-service aircraft from all branches of the US government.
History
AMARG was established in 1946, shortly after World War II as the 4105th Army Air Force Unit to house B-29 and C-47 aircraft. Davis-Monthan Air Force Base was chosen because of Tucson's low humidity, infrequent rainfall, alkaline soil and high altitude of 2,550–2,900 ft (780–880 m), reducing rust and corrosion. The hard soil makes it possible to move aircraft around without having to pave the storage areas.
In 1948, after the Air Force's creation as a separate service, the unit was renamed the 3040th Aircraft Storage Depot. In 1965, the depot was renamed the Military Aircraft Storage and Disposition Center (MASDC), and tasked with processing aircraft for all the US armed forces (not just the Air Force). In the 1980s, the center began processing ICBMs for dismantling or reuse in satellite launches, and was renamed the Aerospace Maintenance and Regeneration Center (AMARC) to reflect the expanded focus on all aerospace assets.
In the 1990s, in accordance with the START I treaty, AMARG was tasked with eliminating 365 B-52 bombers. The progress of this task was to be verified by Russia via satellite and first-person inspection at the AMARG facility. Initially, the B-52s were chopped into pieces with a 13,000-pound guillotine winched by a steel cable, supported by a crane. Later on, the tool of choice became K-12 rescue saws. This more precise technique afforded AMARG with salvageable spare parts.
In May 2007, command of AMARC was transferred to the 309th Maintenance Wing, and the center was renamed the 309th Aerospace Maintenance and Regeneration Group
Storage procedures
There are four categories of storage for planes at AMARG:
Long Term - Aircraft are kept intact for future use
Parts Reclamation - Aircraft are kept, picked apart and used for spare parts
Flying Hold - Aircraft are kept intact for shorter stays than Long Term
Excess of DoD needs - Aircraft are sold off whole or in parts
AMARG employs 550 people, almost all civilians. The 2,600 acres (11 km2) facility is adjacent to the base. For every $1 the federal government spends operating the facility, it saves or produces $11 from harvesting spare parts and selling off inventory. Congressional oversight determines what equipment may be sold to which customer.
An aircraft going into storage undergoes the following treatments:
All guns, ejection seat charges, or classified hardware are removed.
The fuel system is protected by draining it, refilling it with lightweight oil, and then draining it again. This leaves a protective oil film.
The aircraft is sealed from dust, sunlight, and high temperatures. This is done using a variety of materials, ranging from a high tech vinyl plastic compound, called spraylat, of a opaque white colour sprayed on the aircraft, to simple garbage bags. The plane is then towed by a jeep to its designated "storage" position.
The Group annually in-processes an undisclosed number of aircraft for storage and out-processes a number of aircraft for return to the active service, either repainted and sold to friendly foreign governments, recycled as target or remotely controlled drones or rebuilt as cargo planes. For instance, Turkey has purchased several Vietnam-era jets in recent years that had been kept at AMARG. There is much scrutiny over who (civilians, companies, foreign governments) and what kind of parts they may buy. At times, these sales are canceled, the Air Force for example reclaimed several F-16s from AMARG for the Strike Fighter Tactics Instructor Courses and which were originally meant to be sold to Pakistan, but were never delivered due to an embargo at that time.
Accessibility
AMARG is closely guarded, and is off-limits to anyone not employed there. The only exception is a bus tour which is conducted by the nearby Pima Air & Space Museum.
Use in movies and TV
AMARC has also been site of filming for scenes in several movie and television productions, despite the rather heavy security of AMARG and the base in general. The most recent and notable of these is Transformers: Revenge of the Fallen. The exterior scenes of the Smithsonian set were actually filmed in the Boneyard. The background of several shots can be clearly recognized while looking toward the fence-line from one of the major streets that run along the perimeter. Others include the 1991 movie Harley Davidson and the Marlboro Man; the music video for Tom Petty and the Heartbreakers' song Learning To Fly; and various other productions
Other interesting website about The AMARC Aka The Boneyard : Wikimapia
Source : Wikipedia
Anna Mitchell-Hedges and a Crystal Skull.
The AMARC aka The
Boneyard
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The Diavik Diamond Mine
The Diavik Diamond Mine is a diamond mine in the North Slave Region of the Northwest Territories, Canada, about 300 kilometres (186 miles) north of Yellowknife. It has become an important part of the regional economy, employing 700, grossing C$100 million in sales, and producing 8 million carats (1600 kg) of diamonds annually. The area was surveyed in 1992 and construction began in 2001, with production commencing in January 2003. It is connected by an ice road and Diavik Airport with a 5,235-foot (1,596 m) gravel runway regularly accommodating Boeing 737 jet aircraft.
The mine is owned by a joint venture between the Harry Winston Diamond Corporation and Diavik Diamond Mines Inc., a subsidiary of Rio Tinto Group. The lifespan of the mine is expected to be 16 to 22 years.
The mine consists of three kimberlite pipes associated with the Lac de Gras kimberlite field and is located on an island 20 square kilometres (8 sq mi) in Lac de Gras and is informally called East Island. It is about 220 kilometres (137 mi) south of the Arctic Circle.
In 2006 the ice road from Yellowknife to the Diavik mine, and neighboring mines, froze late and thawed early. The Diavik mine was unable to truck in all the supplies needed for the rest of 2006 before the road closed and arrangements had to be made to bring the remainder of the supplies in by air.
On July 5, 2007 a consortium of seven mining companies, including Rio Tinto, announced they are sponsoring environmental impact studies to construct a deep-water port in Bathurst Inlet.Their plans include building a 211 km (131 mi) road connecting the port to their mines. The port would serve vessels of up to 25,000 tonnes.
Other interesting website about The Diavik Diamond Mine : Niceice
Source : Wikipedia
The Diavik Diamond Mine
The Diavik Diamond Mine
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The Mir Diamond Mine
The Mir Mine (Russian: Кимберлитовая алмазная трубка "Мир" Kimberlitovaya Almaznaya Trubka "Mir"; English: kimberlite diamond pipe "Peace") also called Mirny Mine was an open pit diamond mine located in Mirny, Eastern Siberia, Russia. The mine is 525 meters (1,722 ft) deep and has a diameter of 1,200 m (3,900 ft), and is the second largest excavated hole in the world, after Bingham Canyon Mine. The airspace above the mine is closed for helicopters because of a few incidents in which they were sucked in by the downward air flow.
The mine was discovered on June 13, 1955 by Soviet geologists Yuri Khabardin, Ekaterina Elagina and Viktor Avdeenko during the large Amakinsky Expedition in Yakut ASSR. They found traces of volcanic rock kimberlite which are usually associated with diamonds. This finding was the first success in the search for kimberlite in Russia, after numerous failed expeditions of the 1940s and 1950s. For this discovery, in 1957 Khabardin was given the Lenin Prize, which was one of the highest awards in the Soviet Union.
The development of the mine had started in 1957 in extremely harsh climate conditions. Seven months of winter per year froze the ground into permafrost, which was hard in winter, but turned into sludge in summer. Buildings had to be raised on piles, so that they would not sink in summer, and the main processing plant had to be built on a better ground found 20 km away from the mine. The winter temperatures were so low that car tires and steel would shatter and oil would freeze. During the winter, the workers used jet engines to defreeze and dig out the permafrost or blasted it with dynamite to get access to the underlying kimberlite. The entire mine had to be covered at night to prevent the machinery from freezing.
In the 1960s the mine was producing 10 million carats (2 tonnes) of diamond per year, of which a relatively high fraction (20%) were of gem quality. The upper layers of the mine (down to 340 meters) had very high diamond content of 4 carats per tonne of ore, with the relatively high ratio of gems to industrial stones. The yield decreased to 1.5-2 carat/tonne and the production rate slowed to 2 million carats per year near the pit bottom. The largest diamond of the mine was found on 23 December 1980; it weighed 342.5 carats (68 g) and was named "26th Congress CPSU" (Russian: XXVI съезд КПСС). The mine operation was interrupted in 1990s at a depth of 340 m after the pit bottom became flooded but resumed later.
The rapid development of the Mir mine had worried De Beers company, which at that time was distributing most of the world's diamonds. De Beers had to buy Russian diamonds in order to control the market price, and therefore needed to know as much as possible about the Russian mining developments. In the 1970s, De Beers requested permission to visit the Mir mine. Permission was granted under condition that Russian experts would visit De Beers diamond mines in South Africa. De Beers executive Sir Philip Oppenheimer and chief geologist Barry Hawthorne arrived in Moscow in the summer of 1976. They were intentionally delayed in Moscow by arranging a series of meetings and lavish banquets with Soviet geologists, mineralogists, engineers and mine managers. When Oppenheimer and Hawthorne finally reached the Mir mine, their visas were about to expire, so that they could only have 20 minutes at the Mir mine. Even that short time was sufficient to get some important details. For example, the Russians did not use water during the ore processing at all, which was astonishing to De Beers. The reason was that water would freeze most of the year, and dry crushing was used instead. De Beers also overestimated the size of the mine's pit.
The Mir mine was the first and the largest diamond mine in the Soviet Union. Its surface operation lasted 44 years, finally closing in June 2001.[10] After the collapse of the USSR, in the 1990s, the mine was operated by the Sakha diamond company, which reported annual profits in excess of $600 million from diamond sales.
Currently, the mine is operated by Alrosa, the largest diamond producing company in Russia, and employs 3600 workers. It has long been anticipated that the recovery of diamonds by conventional surface methods will saturate. Therefore, in 1970s construction has started of a network of underground tunnels for diamond recovery. Production of diamonds by this method started in 1999 and is estimated to last for another 27 years. This estimate is based on depth explorations down to 1220 meters. In order to stabilize the abandoned main pit, its bottom was covered by a rubble layer 45 meters thick.
Other interesting website about The Mir Diamond Mine : Atlasobscura
Source : Wikipedia
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The Burj Khalifa a.k.a. the tallest man-made structure ever built.
Burj Khalifa (Arabic: برج خليفة "Khalifa Tower"), known as Burj Dubai prior to its inauguration, is a skyscraper in Dubai, United Arab Emirates, and the tallest man-made structure ever built, at 828 m (2,717 ft). Construction began on 21 September 2004, with the exterior of the structure completed on 1 October 2009. The building officially opened on 4 January 2010. The building is part of the 2 km2 (490-acre) flagship development called Downtown Burj Khalifa at the "First Interchange" along Sheikh Zayed Road, near Dubai's main business district.
The tower's architecture and engineering were performed by Skidmore, Owings, and Merrill of Chicago. Adrian Smith, who started his own firm in 2006, was the chief architect, and Bill Baker was the chief structural engineer for the project. The primary contractor was Samsung C&T of South Korea, who also built the Taipei 101 and Petronas Twin Towers. Major subcontractors included Belgian group Besix and Arabtec from the UAE. Turner Construction Company was chosen as the construction project manager. Under UAE law, the Contractor and the Engineer of Record, Hyder Consulting, is jointly and severally liable for the performance of Burj Khalifa.
The total cost for the Burj Khalifa project was about US$1.5 billion; and for the entire new "Downtown Dubai", US$20 billion. Mohamed Ali Alabbar, the Chairman of Emaar Properties, speaking at the Council on Tall Buildings and Urban Habitat 8th World Congress, said in March 2009 that the price of office space at Burj Khalifa had reached US$4,000 per sq ft (over US$43,000 per m2) and that the Armani Residences, also in Burj Khalifa, were selling for US$3,500 per sq ft (over US$37,500 per m2).
The project's completion coincided with a worldwide economic slump and overbuilding, and it has been described as "the latest ... in string of monuments to architectural vacancy."With Dubai itself mired in a deep financial crisis that forced it to seek repeated billion-dollar bailouts from its oil-rich neighbor Abu Dhabi, the opening ceremony and surprise renaming of the tower to Burj Khalifa, after UAE President Khalifa bin Zayed Al Nahyan, has been viewed by observers as an "attempt to boost confidence in Dubai by showing who is backing Dubai"
Height
Current records
Tallest skyscraper to top of spire: 828 m (2,717 ft) (previously Taipei 101 – 509.2 m/1,671 ft)
Tallest structure ever built: 828 m (2,717 ft) (previously Warsaw radio mast – 646.38 m/2,121 ft)
Tallest extant structure: 828 m (2,717 ft) (previously KVLY-TV mast – 628.8 m/2,063 ft)
Tallest freestanding structure: 828 m (2,717 ft) (previously CN Tower – 553.3 m/1,815 ft)
Building with most floors: 160 (previously Willis Tower – 108)
World's highest elevator installation, situated inside a rod at the very top of the building
World's fastest elevators at speed of 64 km/h (40 mph) or 18 m/s (59 ft/s)[20] (previously Taipei 101 – 16.83 m/s)
Highest vertical concrete pumping (for a building): 606 m (1,988 ft)(previously Taipei 101 – 449.2 m/1,474 ft)
Highest vertical concrete pumping (for any construction): 606 m (1,988 ft)(previously Riva del Garda Hydroelectric Power Plant – 532 m/1,745 ft)
The first world's tallest structure in history to include residential space
Highest outdoor observation deck in the world (124th floor) at 442 m (1,450 ft)
World's highest mosque (located on the 158th floor)
World's highest installation of an aluminium and glass façade, at a height of 512 m (1,680 ft)
World's highest swimming pool (76th floor)
History of height increases
There are unconfirmed reports of several planned height increases since its inception. Originally proposed as a virtual clone of the 560 m (1,837 ft) Grollo Tower proposal for Melbourne, Australia's Docklands waterfront development, the tower was redesigned with an original design by Skidmore, Owings and Merrill (SOM) discussed below. Marshall Strabala, an SOM architect who worked on the project until 2006, late 2008 said that Burj Khalifa was designed to be 808 m (2,651 ft) tall.
The design architect, Adrian Smith, felt that the uppermost section of the building did not culminate elegantly with the rest of the structure, so he sought and received approval to increase it to the current height.
It has been explicitly stated that this change did not include any added floors, which is fitting with Smith's attempts to make the crown more slender.
Delay
Emaar Properties announced on 9 June 2008 that construction of Burj Khalifa was delayed by upgraded finishes and would be completed only in September 2009. An Emaar spokesperson said "The luxury finishes that were decided on in 2004, when the tower was initially conceptualized, is now being replaced by upgraded finishes. The design of the apartments has also been enhanced to make them more aesthetically attractive and functionally superior."A revised completion date of 2 December 2009 was then announced. However, Burj Khalifa was opened on 4 January 2010.
Architecture and design
The tower is designed by Skidmore, Owings and Merrill, which also designed the Willis Tower (formerly the Sears Tower) in Chicago, Illinois and 1 World Trade Center in New York City, among numerous other famous high-rises. The building resembles the bundled tube form of the Willis Tower, but is not a bundle tube structure. Its design is reminiscent of Frank Lloyd Wright's vision for The Illinois, a mile-high skyscraper designed for Chicago. According to Marshall Strabala, an SOM architect who worked on the building's design team, Burj Khalifa was designed based on the 73-floor Tower Palace Three, an all-residential building in Seoul, South Korea. In its early planning, Burj Khalifa was intended to be entirely residential.
Subsequent to the original design by Skidmore, Owings and Merrill, Emaar Properties chose Hyder Consulting to be the supervising engineer. Hyder was selected for its expertise in structural and MEP (mechanical, electrical and plumbing) engineering. Hyder Consulting's role was to supervise construction, certify SOM's design, and be the engineer and architect of record to the UAE authorities. Emaar Properties also engaged GHD, an international multidisciplinary consulting firm, to act as an independent verification and testing authority for concrete and steelwork.
The design of Burj Khalifa is derived from patterning systems embodied in Islamic architecture. According to the structural engineer Bill Baker of Burj Khalifa, the building's design incorporates cultural and historical elements particular to the region. The Y-shaped plan is ideal for residential and hotel usage, with the wings allowing maximum outward views and inward natural light. The design architect Adrian Smith has said the triple-lobed footprint of the building was inspired by the flower Hymenocallis. The tower is composed of three elements arranged around a central core. As the tower rises from the flat desert base, setbacks occur at each element in an upward spiralling pattern, decreasing the cross section of the tower as it reaches toward the sky. There are 27 terraces in Burj Khalifa. At the top, the central core emerges and is sculpted to form a finishing spire. A Y-shaped floor plan maximizes views of the Persian Gulf. Viewed from above or from the base, the form also evokes the onion domes of Islamic architecture. During the design process, engineers rotated the building 120 degrees from its original layout to reduce stress from prevailing winds. At its tallest point, the tower sways a total of 1.5 m (4.9 ft).
To support the unprecedented height of the building, the engineers developed a new structural system called the buttressed core, which consists of a hexagonal core reinforced by three buttresses that form the ‘Y' shape. This structural system enables the building to support itself laterally and keeps it from twisting.
The spire of Burj Khalifa is composed of more than 4,000 tonnes (4,400 ST; 3,900 LT) of structural steel. The central pinnacle pipe weighing 350 tonnes (390 ST; 340 LT) was constructed from inside the building and jacked to its full height of over 200 m (660 ft) using a strand jack system. The spire also houses communications equipment.
More than 1,000 pieces of art will adorn the interiors of Burj Khalifa, while the residential lobby of Burj Khalifa will have the artwork of 196 bronze and brass alloy cymbals representing the 196 countries of the world. The visitors in this lobby will be able to hear a distinct timbre as the cymbals, plated with 18-carat gold, are struck by dripping water, intended to mimic the sound of water falling on leaves.
The exterior cladding of Burj Khalifa consists of 142,000 m2 (1,528,000 sq ft) of reflective glazing, and aluminium and textured stainless steel spandrel panels with vertical tubular fins. The cladding system is designed to withstand Dubai's extreme summer temperatures. Additionally, the exterior temperature at the top of the building is thought to be 6°C (11°F) cooler than at its base. Over 26,000 glass panels were used in the exterior cladding of Burj Khalifa. Over 300 cladding specialists from China were brought in for the cladding work on the tower.
The hotel interior will be decorated by Giorgio Armani. An Armani Hotel, the first of four by Armani, will occupy 15 of the lower 39 floors. The hotel will be opened on 18 March 2010. whereas the Corporate Suites and offices, will be opened from March onwards. The sky lobbies on the 43rd and 76th floors will house swimming pools. Floors through to 108 will have 900 private residential apartments (which, according to the developer, sold out within eight hours of being on the market). An outdoor zero-entry swimming pool will be located on the 76th floor of the tower. Corporate offices and suites fill most of the remaining floors, except for a 122nd, 123rd and 124th floor where the At.mosphere restaurant, sky lobby and an indoor and outdoor observation deck is located respectively. Burj Khalifa will receive its first residents from February 2010. They will be among the first of 25,000 people who will live there.
Burj Khalifa is expected to hold up to 35,000 people at any one time.A total of 57 elevators and 8 escalators are installed.The elevators have a capacity of 12 to 14 people per cabin, the fastest rising and descending at up to 18 m/s (59 ft/s). Engineers had considered installing the world's first triple-deck elevators, but the final design calls for double-deck elevators. Double-deck elevators, are with built in light and entertainment features including LCD displays, which serves the visitors throughout their travel to the observation deck. The building has 2,909 stairs from the ground floor to the 160th floor.
The graphic design identity work for Burj Khalifa is the responsibility of Brash Brands, who are based in Dubai. Design of the global launch events, communications, and visitors centers for Burj Khalifa have also been created by Brash Brands as well as the roadshow exhibition for the Armani Residences, which are part of the Armani Hotel within Burj Khalifa, which toured Milan, London, Jeddah, Moscow and Delhi.
Water supply system
The Burj Khalifa's water system supplies an average of 946,000 l (250,000 USgal) of water per day.
At the peak cooling times, the tower requires cooling equivalent to that provided by 10,000 t (22,000,000 lb) of melting ice in one day. The building has a condensate collection system, which uses the hot and humid outside air, combined with the cooling requirements of the building and results in a significant amount of condensation of moisture from the air. The condensed water is collected and drained into a holding tank located in the basement car park, this water is then pumped into the site irrigation system for use on the Burj Khalifa park.
Maintenance
To wash the 24,348 windows, a horizontal track has been installed on the exterior of Burj Khalifa at levels 40, 73 and 109. Each track holds a 1,500 kg (3,300 lb) bucket machine which moves horizontally and then vertically using heavy cables. Above level 109, up to tier 27 traditional cradles from davits are used. The top of the spire, however, is reserved for specialist window cleaners, who brave the heights and high winds dangling by ropes to clean and inspect the top of the pinnacle.Under normal conditions, when all building maintenance units will be operational, it will take 36 workers three to four months to clean the entire exterior facade.
Unmanned machines will clean the top 27 additional tiers and the glass spire. The cleaning system was developed in Australia at a cost of A$8 million.
Dubai Fountain
Outside, and at a cost of Dh 800 million (US$217 million), a record-setting fountain system was designed by WET Design, the California-based company responsible for the fountains at the Bellagio Hotel Lake in Las Vegas. Illuminated by 6,600 lights and 50 coloured projectors, it is 275 m (902 ft) long and shoots water 150 m (490 ft) into the air, accompanied by a range of classical to contemporary Arabic and world music. On 26 October 2008 Emaar announced that based on results of a naming contest the fountain would be called the Dubai Fountain.
Observation Deck
An outdoor observation deck, named At the Top, opened on 5 January 2010 on the 124th floor. It is the third highest observation deck in the world and the highest outdoor observation deck in the world, at 442 m (1,450 ft). To manage the daily rush of sightseers, Emaar Properties offers advance purchase tickets for a specific date and time at a 75% discount over tickets purchased on the spot
On 8 February 2010, the observation deck was closed to the public after power supply problems caused an elevator to become stuck between floors, trapping a group of tourists for 45 minutes. Despite rumours of the observation deck reopening on 14 February, it remains closed.
Burj Khalifa park
Burj Khalifa is surrounded by an 11 ha (27-acre) park designed by landscape architects SWA Group. The design of the park is also inspired by the core design concepts of Burj Khalifa which is based on the symmetries of the desert flower, Hymenocallis.The park has six water features, gardens, palm lined walkways, and flowering trees. At the centre of the park and the base of Burj Khalifa is the water room, which is a series of pools and water jet fountains. In addition the railing, benches and signs incorporate images of Burj Khalifa and the Hymenocallis flower.
The plants and the shrubbery will be watered by the buildings's condensation collection system,that uses water from the cooling system. The system will provide 68,000,000 L (15,000,000 imp gal) annually. WET designers, who also developed the Dubai Fountain, developed the park's six water features.
Construction
The tower was constructed by a South Korean company, Samsung Engineering & Construction, which also did work on the Petronas Twin Towers and Taipei 101.[69] Samsung Engineering & Construction is building the tower in a joint venture with Besix from Belgium and Arabtec from UAE. Turner is the Project Manager on the main construction contract.
The primary structural system of Burj Khalifa is reinforced concrete. Over 45,000 m3 (58,900 cu yd) of concrete, weighing more than 110,000 tonnes (120,000 ST; 110,000 LT) were used to construct the concrete and steel foundation, which features 192 piles, with each pile is 1.5 metre diameter x 43 metre long buried more than 50 m (164 ft) deep.Burj Khalifa's construction used 330,000 m3 (431,600 cu yd) of concrete and 55,000 tonnes of steel rebar, and construction took 22 million man-hours.A high density, low permeability concrete was used in the foundations of Burj Khalifa. A cathodic protection system under the mat is used to minimize any detrimental effects from corrosive chemicals in local ground water.
The previous record for pumping concrete on any project was set during the extension of the Riva del Garda Hydroelectric Power Plant in Italy in 1994, when concrete was pumped to a height of 532 m (1,745 ft). Burj Khalifa exceeded this height on 19 August 2007, and as of May 2008 concrete was pumped to a delivery height of 606 m (1,988 ft), the 156th floor. The remaining structure above is built of lighter steel.
Burj Khalifa is highly compartmentalised. Pressurized, air-conditioned refuge floors are located approximately every 35 floors where people can shelter on their long walk down to safety in case of an emergency or fire.
Special mixes of concrete are made to withstand the extreme pressures of the massive building weight; as is typical with reinforced concrete construction, each batch of concrete used was tested to ensure it could withstand certain pressures.
The consistency of the concrete used in the project was essential. It was difficult to create a concrete that could withstand both the thousands of tonnes bearing down on it and Persian Gulf temperatures that can reach 50 °C (122 °F). To combat this problem, the concrete was not poured during the day. Instead, during the summer months ice was added to the mixture and it was poured at night when the air is cooler and the humidity is higher. A cooler concrete mixture cures evenly throughout and is therefore less likely to set too quickly and crack. Any significant cracks could have put the entire project in jeopardy.
The unique design and engineering challenges of building Burj Khalifa have been featured in a number of television documentaries, including the Big, Bigger, Biggest series on the National Geographic and Five channels, and the Mega Builders series on the Discovery Channel.
Labour controversy
Further information: Human rights in the United Arab Emirates
Burj Khalifa was built primarily by workers from South Asia.Press reports indicated in 2006 that skilled carpenters at the site earned UK£4.34 a day, and labourers earned UK£2.84. According to a BBC investigation and a Human Rights Watch report, the workers were housed in abysmal conditions, their pay was often withheld, their passports were confiscated by their employers, and they were working in hazardous conditions that resulted in an apparently high number of deaths and injuries on site.
On 21 March 2006, about 2,500 workers, who were upset over buses that were delayed for the end of their shifts, protested, damaging cars, offices, computers, and construction equipment. A Dubai Interior Ministry official said the rioters caused almost UK£500,000 in damage. Most of the workers involved in the riot returned the following day but refused to work.
On 17 June 2008, there were 7,500 skilled workers employed in the construction of Burj Khalifa.
Milestones
January 2004: Excavation commences.
February 2004: Piling starts.
21 September 2004: Emaar contractors begin construction.
March 2005: Structure of Burj Khalifa starts rising.
June 2006: Level 50 is reached.
February 2007: Surpasses the Sears Tower as the building with the most floors.
13 May 2007: Sets record for vertical concrete pumping on any building at 452 m (1,483 ft), surpassing the 449.2 m (1,474 ft) to which concrete was pumped during the construction of Taipei 101, while Burj Khalifa reached 130 floor.
21 July 2007: Surpasses Taipei 101, whose height of 509.2 m (1,671 ft) made it the world's tallest building, and level 141 reached.
12 August 2007: Surpasses the Sears Tower antenna, which stands 527.3 m (1,730 ft).
12 September 2007: At 555.3 m (1,822 ft), becomes the world's tallest freestanding structure, surpassing the CN Tower in Toronto, and level 150 reached.
7 April 2008: At 629 m (2,064 ft), surpasses the KVLY-TV Mast to become the tallest man-made structure, level 160 reached.
17 June 2008: Emaar announces that Burj Khalifa's height is over 636 m (2,087 ft) and that its final height will not be given until it is completed in September 2009.
1 September 2008: Height tops 688 m (2,257 ft), making it the tallest man-made structure ever built, surpassing the previous record-holder, the Warsaw Radio Mast in Konstantynów, Poland.
17 January 2009: Topped out at 828 m (2,717 ft).
1 October 2009: Emaar announces that the exterior of the building is completed.
4 January 2010: Burj Khalifa's official launch ceremony is held and Burj Khalifa is opened. Burj Dubai renamed Burj Khalifa in honour of the current President of the UAE and ruler of Abu Dhabi, Sheikh Khalifa bin Zayed al Nahyan.
Opening ceremony
The opening ceremony of Burj Khalifa was held on 4 January 2010. The ceremony featured a display of 10,000 fireworks, light beams projected on and around the tower, and further sound, light and water effects. Using the 868 powerful stroboscope lights that are integrated into the facade and spire of the tower, different lighting sequences were choreographed, together with more than 50 different combinations of the other effects.
The event began with a short film which depicted the story of Dubai and the evolution of Burj Khalifa. The displays of sound, light, water and fireworks followed. The portion of the show consisting of the various pyrotechnic, lighting, water and sound effects was divided into three. The first part was primarily a light and sound show, which took as its theme the link between desert flowers and the new tower, and was co-ordinated with the Dubai Fountain and pyrotechnics. The second portion, called 'Heart Beat', represented the construction of the tower in a dynamic light show with the help of 300 projectors which generated a shadow-like image of the tower. In the third act, sky tracers and space cannons enveloped the tower in a halo of white light, which expanded as the lighting rig on the spire activated.
The ceremony was relayed live on a giant screen on Burj Park Island, as well as several television screens placed across the Downtown Burj Khalifa development. Hundreds of media outlets from around the world reported live from the scene. In addition to the media presence, 6,000 guests were expected.
Purpose
Burj Khalifa has been designed to be the centrepiece of a large-scale, mixed-use development that will include 30,000 homes, nine hotels such as The Address Downtown Burj Khalifa, 3 hectares (7.4 acres) of parkland, at least 19 residential towers, the Dubai Mall, and the 12-hectare (30-acre) man-made Burj Khalifa Lake.
The building has returned the location of Earth's tallest free-standing structure to the Middle East — where the Great Pyramid of Giza claimed this achievement for almost four millennia before being surpassed in 1311 by Lincoln Cathedral in England.
The decision to build Burj Khalifa is reportedly based on the government's decision to diversify from an oil-based economy to one that is service- and tourism-oriented. According to officials, it is necessary for projects like Burj Khalifa to be built in the city to garner more international recognition, and hence investment. "He (Sheikh Mohammed bin Rashid Al Maktoum) wanted to put Dubai on the map with something really sensational," said Jacqui Josephson, a tourism and VIP delegations executive at Nakheel Properties.
BASE jumping
The building has been used by several experienced BASE jumpers for both authorized and unauthorized BASE jumping:
In May 2008, Hervé Le Gallou and an unnamed British man, dressed as engineers, illegally infiltrated Burj Khalifa (around 650 m at the time), and jumped off a balcony situated a couple of floors below the 160th floor.
On 8 January 2010, with permission of the authorities, Nasr Al Niyadi and Omar Al Hegelan, from the Emirates Aviation Society, broke the world record for the highest BASE jump from a building after they leapt from a crane suspended platform attached to the 160th floor at 672 m (2,205 ft). The two men descended the vertical drop at a speed of up to 220 km/h (140 mph), with enough time to open their parachutes 10 seconds into the 90 second jump.
Other interesting website about The The Burj Khalifa : Burjkhalifa
Source : Wikipedia
The Burj Khalifa
The Burj Khalifa Window cleaning
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The Cave of the Crystals
Cueva de los Cristales (Cave of the Crystals) is a cave connected to the Naica Mine 300 metres (980 ft) deep in Chihuahua, Mexico.Naica is a lead, zinc and silver mine in which large voids have been found, containing crystals of selenite (gypsum). The main chamber contains giant selenite crystals, some of the largest natural crystals ever found. The cave's largest crystal found to date is 11 m (36 ft) in length, 4 m (13 ft) in diameter and 55 tons in weight. The cave is about 27 m (89 ft) in length and 9 m (30 ft) in width. The cave is extremely hot with air temperatures reaching up to 58 °C (136 °F)[2] with 90 to 100 percent humidity. The cave is relatively unexplored due to the extreme temperatures and high humidity. Without proper protection people can only endure approximately ten minutes of exposure at a time.
The chamber holding these crystals is known as the Crystal Cave of Giants, and is approximately 1000 feet down in the limestone host rock of the mine. The crystals were formed by hydrothermal fluids emanating from the magma chambers below.
Discovery
The cavern was discovered while the miners were drilling through the Naica fault, which they were worried would flood the mine. The Cave of Swords is another chamber in the Naica Mine, containing similar large crystals.
The Naica mine was first discovered by early prospectors in 1794 south of Chihuahua City. They struck a vein of silver at the base of a range of hills called Naica by the Tarahumara Indians. The origin in the Tarahumara language seems to mean "a shady place". Perhaps here in the small canyon there was a grove of trees tucked away by a small canyon spring.
From that discovery, until around 1900, the primary interest was silver and gold. Around 1900 large-scale mining began as zinc and lead became more valuable.
During the Mexican Revolution the mine was producing a great deal of wealth. Revolutionary troops entered the town and demanded money from the owners. One of them was assassinated when he refused to pay, causing the mine to shut down from 1911 to 1922.
The Cave of Crystals is a horseshoe-shaped cavity in limestone rock about 10 meters wide and 30 meters long. Its floor is covered in perfectly faceted crystalline blocks, and huge crystal beams jut out from both the blocks and the floor. The only reason people can get into the caves today is because the mining company's pumping operations keep the cave clear of water. If the pumping would be stopped, the caves will again be submerged.
In 1910 miners discovered another cavern beneath Naica, the Cave of Swords. It is located over the Cave of Crystals and contains spectacular, but smaller crystals. It is speculated that transition temperatures may have fallen much more rapidly, leading to an end in the growth of the crystals.
Formation of the crystals
Naica lies on an ancient fault and there is an underground magma chamber below the cave. The magma heated the ground water and it became saturated with minerals, including large quantities of gypsum. The hollow space of the cave was filled with this mineral rich hot water and remained filled for about 500,000 years. During this time, the temperature of the water remained very stable at over 50°C. This allowed microscopic crystals to form and grow. They continued to grow to immense sizes.[
In the Media : by Stefan Lovgren for National Geographic News
Giant Crystal Cave's Mystery Solved
It's "the Sistine Chapel of crystals," says Juan Manuel García- Ruiz.
The geologist announced this week that he and a team of researchers have unlocked the mystery of just how the minerals in Mexico's Cueva de los Cristales (Cave of Crystals) achieved their monumental forms.
Buried a thousand feet (300 meters) below Naica mountain in the Chihuahuan Desert, the cave was discovered by two miners excavating a new tunnel for the Industrias Peñoles company in 2000.
The cave contains some of the largest natural crystals ever found: translucent gypsum beams measuring up to 36 feet (11 meters) long and weighing up to 55 tons.
"It's a natural marvel," said García-Ruiz, of the University of Granada in Spain.
To learn how the crystals grew to such gigantic sizes, García-Ruiz studied tiny pockets of fluid trapped inside.
The crystals, he said, thrived because they were submerged in mineral-rich water with a very narrow, stable temperature range—around 136 degrees Fahrenheit (58 degrees Celsius).
At this temperature the mineral anhydrite, which was abundant in the water, dissolved into gypsum, a soft mineral that can take the form of the crystals in the Naica cave.
Other interesting website about The Cave of the Crystals : Stormchaser
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The Cave of Giant Crystals
