Bingham Canyon Mine

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For the former city at this location, see Bingham Canyon, Utah.
Bingham Canyon Mine
Bingham mine 5-10-03.jpg
Mine in 2003
Location
Bingham Canyon Mine is located in Utah
Bingham Canyon Mine
Bingham Canyon Mine
Location Salt Lake County
State Utah
Country United States
Coordinates Lua error in package.lua at line 80: module 'strict' not found.
Production
Products Copper
Type Open-pit
History
Opened 1906 (1906)
Bingham Canyon Open Pit Copper Mine
NRHP Reference # 66000736
Significant dates
Added to NRHP November 13, 1966[1]
Designated NHL November 13, 1966[2]

The Bingham Canyon Mine, more commonly known as Kennecott Copper Mine among locals,[3] is an open-pit mining operation extracting a large porphyry copper deposit southwest of Salt Lake City, Utah, USA, in the Oquirrh Mountains. The mine is owned by Rio Tinto Group, an international mining and exploration company headquartered in the United Kingdom. The copper operations at Bingham Canyon Mine are managed through Kennecott Utah Copper Corporation which operates the mine, a concentrator plant, a smelter, and a refinery. The mine has been in production since 1906, and has resulted in the creation of a pit over 0.6 miles (0.97 km) deep, 2.5 miles (4 km) wide, and covering 1,900 acres (770 ha). It was designated a National Historic Landmark in 1966 under the name Bingham Canyon Open Pit Copper Mine.[2] The mine experienced a massive landslide in April 2013 and a smaller slide in September 2013.[4]

History

Minerals, in the form of copper ore, were first discovered in Bingham Canyon in 1848 by two brothers, Sanford and Thomas Bingham, sons of Erastus Bingham, Mormon pioneers of September 1847, who grazed their cattle there. They reported their find to their leader, Brigham Young, who advised against pursuing mining operations because the survival and establishment of settlements was of paramount importance at that time. The brothers applied themselves to that purpose as directed and did not stake a claim. In 1850, the Bingham family went to settle what is now Weber County, leaving the canyon still today known by their name.[5][6]

Bingham Canyon Mine, November 1942. Carr Fork Canyon as seen from "G" bridge.

It was not until 1863 that extraction of ore began and the potential of the canyon's mineral resources began to be widely recognized. At first, mining was difficult due to the area's rugged terrain, but a railroad reached the canyon in 1873, prompting greatly increased mining activity and accompanying settlement. The canyon's nineteenth-century mines were relatively small, however, and it was not until 1898 that plans for very large-scale exploitation of the canyon's ore bodies began to develop. That year, Samuel Newhouse and Thomas Weir formed the Boston Consolidated Mining Company, intending to increase mine development in the canyon.

A more significant development took place in 1903, when Daniel C. Jackling and Enos A. Wall organized the Utah Copper Company. Utah Copper immediately began construction of a pilot mill at Copperton, just beyond the mouth of the canyon, and the company actually started mining in 1906. The success of Utah Copper in mining the huge but low-grade porphyry copper type orebody at Bingham Canyon revolutionized the copper industry, and set the pattern for the large open-pit porphyry copper mines that today dominate the copper industry worldwide. Utah Copper and Boston Consolidated merged in 1910. The Kennecott Copper Corporation, established in 1903 to operate mines in Kennecott, Alaska, purchased a financial interest in Utah Copper in 1915 and fully acquired the company in 1936.

Bingham's Canyon mine expanded rapidly, and by the 1920s the region was a beehive of activity. Some 15,000 people of widely varying ethnicity lived in the canyon, in large residential communities constructed on the steep canyon walls. The population declined rapidly as mining techniques improved, however, and several of the mining camps began to be swallowed up by the ever-expanding mine. By 1980, when Lark was dismantled, only Copperton, at the mouth of Bingham Canyon and with a population of 800, remained.

In 1985 mining was halted because outmoded equipment had driven the cost of extracting the copper beyond the current selling price. The owners responded by replacing an antiquated 1000-car railroad with conveyor belts and pipelines for transporting the ore and waste, which reduced costs by nearly 30 percent and returned the operation to profitability.[7] For years it was the largest open-pit mine in the world, it is still among the world's largest open-pit mines. Work to expand the mine 600 feet (180 m) east began in 2005, continuing to increase its size, growth, and capabilities.[citation needed]

Landslides

Bingham Canyon Mine satellite images before (left, July 20, 2011) and after (right, May 2, 2013) a landslide on April 20, 2013

At 9:30 pm on April 10, 2013, a landslide occurred at the mine. It was the largest non-volcanic landslide in the history of North America. Around 65–70 million cubic meters (2.3×10^9–2.5×10^9 cu ft) of dirt and rock thundered down the side of the pit.[8] Understanding that the mine's steep walls made it a high risk for landslides, an interferometric radar system had been installed to monitor the ground's stability. As a result of warnings produced by this system, mining operations were shut down the previous day in anticipation of the slide. There were no injuries.[9] The massive slide is expected to cut production of mined copper by 100,000 tonnes (110,000 short tons).[10] A second slide caused an evacuation of 100 workers on September 11, 2013.[11]

Environmental history

According to environmental specialists, the mine has had adverse environmental effects on the habitats of fish and wild animals as well as air and water pollution, creating health hazards to the surrounding public.[12] Different federal agencies concerned with environmental conservation have used strict legal rules to pressure the subsidiary of Kennecott copper mine to comply with environmental regulations. Since the early 1990s, the mine has spent more than $400 million on clean up efforts on the affected areas to avoid regulatory laws that would have placed them on the Superfund National Priorities List (NPL).[13]

Geology

Cross-section through open pit, showing ore zonation, USGS.

The Bingham Canyon orebody is a porphyry copper deposit, formed by a quartz monzonite porphyry intruded into sedimentary rocks. It has the concentric alteration pattern and mineralogic zonation typical of porphyry copper deposits.

The oldest rocks at Bingham Canyon--sandstones, quartzites and limestones—were originally deposited as sediment by the shallow seas that covered the region 300 million years ago (in the late Paleozoic Era). Much later, between 60 and 135 million years ago, extensive folding and faulting of the sediments created the Oquirrh Mountains.

Geologic map showing bedrock geology and alteration zones, USGS.

Thirty to 40 million years ago, massive igneous intrusions initiated the process of mineralization. Extreme pressure forced superheated, mineral-rich solutions into fractured intrusive and adjacent sedimentary rock. Upon cooling, the mineralized solutions deposited enormous quantities of metals throughout a broad section of igneous and sedimentary rock that is now known as the Bingham Stock.[citation needed]

Bingham Canyon is not presently a source of notable mineral specimens. The Bingham Stock is a porphyry deposit, meaning that copper minerals—primarily chalcopyrite—are present in very low grades and disseminated throughout the granite-like host rock as tiny grains, seams and fracture coatings.

Recovery process

Lua error in package.lua at line 80: module 'strict' not found. The extracted ore is treated at the Kennecott smelter at nearby Magna, Utah. The ore is run through a concentrator, where huge grinding mills reduce it to the consistency of face powder. Flotation then separates the gangue from the metalliferous particles, which float off as a 28-percent concentrate of copper along with lesser amounts of silver, gold, lead, molybdenum, platinum and palladium. A selective flotation step separates the molybdenite (molybdenum disulfide) from the chalcopyrite.

The filtered concentrate slurry is piped 17 miles (27 km) to the smelter, where it is dried, and then injected along with oxygen into a flash smelting furnace to oxidize the iron and sulfur. The oxidized iron is skimmed off, while the sulfur dioxide gas is captured and sent to an on-site acid plant for conversion to valuable sulfuric acid - a million tons of it each year.

Left behind is a molten copper sulfide called matte. The 70-percent-copper matte is water-quenched to form a sand-like solid, then injected, with oxygen, into a flash-converting furnace that produces molten, 98.6-percent-pure copper. This copper is then cast into 700-pound (320 kg) anode plates and shipped by rail to the refinery.

At the refinery, the anode plates are pressed flat and interleaved with stainless steel cathode blanks. Automated robotic vehicles place the prepared anodes in cells containing an acidic electrolyte. When the cells are electrified, the anodes slowly dissolve, freeing copper ions that are deposited on the cathode as 99.99-percent-pure copper.

Impurities and precious metals settle to the bottom of the electrolytic cells as anode slimes. A chlorination leaching process recovers the gold and silver, which is melted in induction furnaces.

Production

Over its life, Bingham Canyon has proven to be one of the world's most productive mines. As of 2004, ore from the mine yielded more than 17 million tons (15.4 Mt) of copper, 23 million ounces (715 t) of gold, 190 million ounces (5,900 t) of silver, and 850 million pounds (386 kt) of molybdenum. The value of the resources extracted from the Bingham Canyon Mine is greater than the Comstock Lode, Klondike, and California gold rush mining regions combined. Mines in Chile, Indonesia, Arizona, and New Mexico now[when?] exceed Bingham Canyon's annual production rate. High molybdenum prices in 2005 made the molybdenum produced at Bingham Canyon in that year worth more than the copper.[14] The value of metals produced in 2006 at Bingham Canyon was US$1.8 billion.[15]

Operations

Utah Copper Co. Mill, Bingham Canyon, circa 1910

Kennecott’s Bingham Canyon Mine is the largest man-made excavation in the world, and some claim that it is the only manmade feature visible to the naked eye from an orbiting space shuttle.[16][17][18] Employing 1,800 employees and hundreds of contractors[when?], 450,000 short tons (400,000 long tons; 410,000 t) of material are removed from the mine daily. Electric shovels can carry up to 56 cubic yards (43 m3) or 98 short tons (88 long tons; 89 t) of ore in a single scoop. Ore is loaded into a fleet of 64 large dump trucks which each carry 255 short tons (228 long tons; 231 t) of ore at a time; the trucks themselves cost about $3 million each. There is a five-mile (8 km) series of conveyors that take ore to the Copperton concentrator and flotation plant. The longest conveyor is 3 miles (4.8 km) long.[19]

As of 2010, Kennecott Utah Copper was the second largest copper producer in the US, and provided about 13-18% percent of the U.S.'s copper needs.[16][17] It is one of the top producing copper mines in the world with production at more than 18.7 million short tons (16.7 million long tons; 17.0 Mt). Every year, Kennecott produces approximately 300 thousand short tons (272 kt or 268 thousand long tons) of copper, along with 400 thousand troy ounces (13.7 short tons 12.4 tonnes, or 12.2 long tons) of gold, 4 million troy ounces (124 tonnes, 137 short tons or 122 long tons) of silver, about 10 thousand short tons (9,100 tonnes or 8,900 long tons) of molybdenum,[16] and about a million short tons (910 kt or 890 thousand long tons) of sulfuric acid, a by-product of the smelting process.[18] Rio Tinto purchased Kennecott Utah Copper in 1989 and has invested about $2 billion in the modernization of KUC’s operations. KUCC has also spent more than $350 million on the cleanup of historic mining waste and $100 million on mining waste cleanup.[citation needed]

The current mine plan will expire in 2019. Rio Tinto has been studying a plan to extend the open pit 1,000 feet (305 m) southward, which would extend the life of the mine into the mid-2030s. The plan has been contingent on approval by the Rio Tinto board of directors and approximately 25 required environmental permits.[20]

Environmental impact

In 1990, homes that had been built on former flood plains were discovered to be contaminated with high levels of lead and arsenic.[21] Activities to clean up 100 years of accumulated impacts began in the 1990s, under state Utah Department of Environmental Quality and federal oversight and are ongoing.[22]

The EPA lists "Kennecott South Zone/Bingham" on its superfund webpage, because it was proposed to be listed as a superfund site in 1994, but voluntary clean up of their contaminated lands allowed the company to avoid regulatory issues of being on the NPL. The proposal was withdrawn in 2008.[23] The South Zone includes the Bingham Mining District in the Oquirrh Mountains, about 25 miles southwest of Salt Lake City, the open pit, waste rock dumps, Copperton Mill and other historic sites. More than 25 million tons of mining wastes have been removed, sludge with elevated sulfate concentrations was consolidated and capped on site.[citation needed]

1900 - 1909

By 1904, there were three large copper smelters and one lead smelter in the Salt Lake valley. The sulphur dioxide gas emissions from the smokestacks caused significant crop damage to neighboring crops. During the 1904-1905 winter, the farmers gathered together and decided to file suit against the smelters in the United States District Court of Utah.[24] In 1906, Federal Court Judge Marshall ruled that the smelters could not smelt ores containing more than 10% sulphur,[25] effectively closing all of the aforementioned smelters.

Panorama of the mines of the Utah Copper Company and the Boston Consolidated Mining Company in 1907.

1910 - 1979

Kennecott Copper Mines was formed in 1910 after a merger of Utah Copper and Kennecott copper mining companies.[26] By 1912, environmental protection organizations were complaining about high levels of asbestos being used in the organization. Kennecott Corporation was using asbestos for preventing fires since copper processing requires very high temperatures.[27] Copper has a very high boiling point and also requires use of other chemicals to separate it from other metals and impurities present in the ore. Asbestos has microscopic particles that dispersed into the atmosphere and contributed to illnesses among workers and individuals living near the mines. Asbestos is responsible for illnesses such as pleural fibrosis, skin warts and lung cancer.[27][28]

Kennecott Corporation was also cited as contributing to emissions of heavy metals such as arsenic and mercury.[29] By 1940, arsenic and mercury were also some of the concerns that were raised by environmental protection agencies against Kennecott Corporation.[30] Both mercury and arsenic are dangerous to health in large quantities.[26][31]

1980 - 1989

Chemical spills, 1980-1989
Year Amount Substance Released Cause
1989 100,000,000 gal (est) Process water containing arsenic Unknown[32]

Investigations in the 1980s revealed contamination in the groundwater caused by mining operations the release of hazardous materials. The State of Utah proceeded with legal action against Kennecott and filed a damage claim against the mine in October, 1986, for the loss and destruction of the natural resources, specifically the groundwater.[33][34]

There was also a threat due to the tailings dam. An engineering report in March, 1988, gave information that the tailings dam overshadowing the town of Magna had threat of collapse due to an earthquake and that the billion-ton tailings pond would bury the homes nearby if the tailing pond’s embankment failed. The mine responded by proposing various potential strategies including buying up entire subdivisions near the tailings pond, calculating the company’s liability if the embankment failed, investing $500 million to reinforce the embankment, and colluding with state regulators to keep the engineering report out of the public eye.[35]

1990 - 1999

Chemical spills, 1990-1999
Year Amount Substance Released Cause
1999 100,000,000 gal (est) Process water containing arsenic Unknown[32]
1998 unknown Acid rock drainage Clogged pipe
1997 unknown Copper sulphate Clogged outlet valve
1997 unknown Process water with pH 2.5-4.0 Ruptured pipeline
1993 45,000 gal Wastewater Transfer line rupture
1991 30,000 gal Industrial wastewater Line break

Starting in the beginning of 1990s, dust emissions from mining began polluting surrounding areas, caused by an area near the mine where PM10 levels (particulate matter larger than 10 µg/m³) began to rise from 28μg/m³ to 50μg/m³, posing a severe health concerns for residents. The first report of PM10 rising was proposed by Schwartz and Dockery in 1992. Then, in 1997, Carter (a professor at Brigham Young University) put forward that the mine discharge of PM10 has caused lung damage to neighboring residents.

In 1995, due to scientific research showing that mining had caused the pollution of groundwater, Utah passed laws to make Kennecott companies pay $37 million to control water pollution.

As a result of mine discharge sewage containing large amounts of arsenic and selenium – selenium being particularly toxic to birds, fish and amphibians – about 30% of the fish population were killed in the early 1990s. In 1995 Kennecott, EPA and the State of Utah signed an agreement saying that Kennecott will continue to clean up the discharge sewage.[36]

2000 - 2014

From 2000 through 2011 the Bingham Canyon copper mine has had several chemical spills.[37]

Chemical spills, 2000-2014
Year Amount Substance Released Cause
2011 145,424 gal Copper tailings Equipment malfunction
2011 100,000-290,000 gal Copper tailings Unknown
2011 160,000 gal Tailings Unknown
2010 4,000-5,000 gal Sulfuric acid Unknown
2007 1,240,000 gal Process water containing arsenic Cold temperatures
2006 270,000 gal Process water Pump failure
2006 660,000 gal Process water containing arsenic Cracked pipe
2006 1,000,000 gal Process water Failed indicator
2004 4,000,000 gal Process water containing arsenic Cracked pipe
2004 2,000,000 gal Process water containing arsenic Ruptured process water line
2004 202,000 gal Process water Pipeline failure
2003 70 tons Copper concentrate Unknown
2003 10.27 tons Copper concentrate containing arsenic, copper and lead Pipeline rupture
2003 240,681 tons Copper, arsenic and lead Copper concentrate pipeline rupture
2002 5,800 gal Process water from slag pot Plugged drain line
2001 19 lbs Arsenic, chromium and lead Tailings pipeline failure
2000 110 tons Ore slurry Leak in ore line
2000 18,000 tons Sulfuric acid Flange failure

The EPA has estimated a 72-mile plume of contaminated groundwater has been created over the course of the mine due to multiple spills and runoff. Long-term effects of the underground water supply contamination may include an increased demand for surface water solutions as the population of the Salt Lake valley grows since the county will not be able to tap into the groundwater supply.[37]

In 2007, Kennecott Utah Copper LLC was considering expanding its land holdings to Rose Canyon Ranch in the southern Oquirrh mountains and Yellow Fork Canyon land in Salt Lake County. Kennecott claims rights to file a mining claim in accordance with the Stock-Raising Homestead Act of 1916.[38]

In 2008, the United States Department of Interior Fish and Wildlife Service sued Kennecott after the release of hazardous substances including selenium, copper, arsenic, zinc, lead, and cadmium. A federal biologist claimed that these chemicals have caused great damage to the ecosystems and resources that support the migrant bird populations, as well as other fish and wildlife habitats.[34]

In the northern zone near Magna, Utah, the extensive southern tailings pond has been collecting the tailings since the mine first started mining production. Kennecott Utah Copper LLC has requested permission for a Tailings Expansion Project (TEP) to expand the tailings pond impoundment in Magna, which is already at 1.8 billion ton capacity,[35] and to expand on 721 new acres of wetlands south of the Great Salt Lake. The company has come under scrutiny for the instability of the structure. The Salt Lake Tribune published a report in 2007 revealing that the company failed to disclose information on possible damages that could occur if the tailings pond collapsed in the event of a major earthquake. From 2001 through 2009 there have been six earthquakes ranging from 2.3 to 3.4 in magnitude with an average epicenter only 3 miles away from Magna.[39]

See also

References

  1. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  2. ↑ 2.0 2.1 Lua error in package.lua at line 80: module 'strict' not found.
  3. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  4. ↑ Second landslide hits Rio's Bingham Canyon mine, 100 workers evacuated 16 September 2013
  5. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  6. ↑ The Descendants of Erastus Bingham and Lucinda Gates, Ogden, Utah: Bingham Family Corp, 1970. pp. 3-4.
  7. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  8. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  9. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  10. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  11. ↑ http://www.deseretnews.com/article/865586245/Movement-at-Bingham-Canyon-Mine-stops-operation-evacuates-100-employees.html?pg=all
  12. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  13. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  14. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  15. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  16. ↑ 16.0 16.1 16.2 Lua error in package.lua at line 80: module 'strict' not found.
  17. ↑ 17.0 17.1 Lua error in package.lua at line 80: module 'strict' not found.
  18. ↑ 18.0 18.1 Lua error in package.lua at line 80: module 'strict' not found.
  19. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  20. ↑ "Bingham Canyon extension could extend life of mine to mid-2030s by moving south wall," Mining Engineering, October 2010, p.10.
  21. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  22. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  23. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  24. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  25. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  26. ↑ 26.0 26.1 Lua error in package.lua at line 80: module 'strict' not found.
  27. ↑ 27.0 27.1 Lua error in package.lua at line 80: module 'strict' not found.
  28. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  29. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  30. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  31. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  32. ↑ 32.0 32.1 Lua error in package.lua at line 80: module 'strict' not found.
  33. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  34. ↑ 34.0 34.1 Lua error in package.lua at line 80: module 'strict' not found.
  35. ↑ 35.0 35.1 Lua error in package.lua at line 80: module 'strict' not found.
  36. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  37. ↑ 37.0 37.1 Lua error in package.lua at line 80: module 'strict' not found.
  38. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  39. ↑ Lua error in package.lua at line 80: module 'strict' not found.
General
  • Kennecott Utah Copper Mine brochure (distributed to visitors), dated September 2004.

External links

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