Bingham Canyon Mine

From Wikipedia, the free encyclopedia
  (Redirected from Bingham Canyon)
Jump to: navigation, search
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 40.523°N 112.151°W / 40.523°N 112.151°W / 40.523; -112.151Coordinates: 40.523°N 112.151°W / 40.523°N 112.151°W / 40.523; -112.151
Production
Products Copper
Type Open-pit
History
Opened 1906 (1906)
Bingham Canyon Open Pit Copper Mine
Governing body Private
NRHP Reference # 66000736
Significant dates
Added to NRHP November 13, 1966[1]
Designated NHL November 13, 1966[2]

The Bingham Canyon Mine, also known as the Kennecott Copper Mine, 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 of 2013 and a smaller slide in September of 2013.[3]

History[edit]

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 family's and other's cattle and horses 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.[4][5]

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.[6] 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.

Landslides[edit]

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.[7] Mining operations were shut down the previous day in anticipation of the slide.[8] The massive slide is expected to cut production of mined copper by 100,000 tonnes (110,000 short tons).[9] A second slide caused an evacuation of 100 workers on September 11, 2013.[10]

Geology[edit]

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[edit]

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 99.9-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[edit]

Over its life, Bingham Canyon has proven to be one of the world's most productive mines. As of 2004, ore from the mine has 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 exceed Bingham Canyon's annual production rate. High molybdenum prices in 2005 made the molybdenum produced at Bingham Canyon in that year worth even more than the copper.[11] The value of metals produced in 2006 at Bingham Canyon was US$1.8 billion.[12]

Operations[edit]

Utah Copper Co. Mill, Bingham Canyon, circa 1910

Employing 1,800 employees and hundreds of contractors, 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 US 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.[13]

As of 2010, Kennecott Utah Copper is the second largest copper producer in the United States and provides about 13-18% percent of the U.S.'s copper needs.[14][15] Kennecott’s Bingham Canyon Mine is the largest man-made excavation in the world, and is visible with the naked eye from space.[14][15][16] 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,[14] and about a million short tons (910 kt or 890 thousand long tons) of sulfuric acid, a by-product of the smelting process.[16] 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.

The current mine plan will expire in 2019. Rio Tinto is currently 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 is contingent on approval by the Rio Tinto board of directors and approximately 25 required environmental permits.[17]

See also[edit]

References[edit]

  1. ^ "National Register Information System". National Register of Historic Places. National Park Service. 2007-01-23. 
  2. ^ a b "Bingham Canyon Open Pit Copper Mine". National Historic Landmark summary listing. National Park Service. Retrieved 2008-07-12. 
  3. ^ Second landslide hits Rio's Bingham Canyon mine, 100 workers evacuated 16 September, 2013
  4. ^ Crump, Scott (1994), "Bingham Canyon", in Powell, Allan Kent, Utah History Encyclopedia, Salt Lake City, Utah: University of Utah Press, ISBN 0874804256, OCLC 30473917 
  5. ^ The Descendants of Erastus Bingham and Lucinda Gates, Ogden, Utah: Bingham Family Corp, 1970. pp. 3-4.
  6. ^ Tasa, Frederick K. Lutgens, Edward J. Tarbuck ; illustrated by Dennis (2012). Essentials of geology (11th ed. ed.). Boston: Prentice Hall. p. 57. ISBN 978-0321714725. 
  7. ^ "Sizing up the Landslide at Bingham Canyon Mine". Earth Observatory. NASA. 
  8. ^ Romero, McKenzie; Adams, Andrew (April 11, 2013). "Massive landslide stops production at Bingham Canyon Mine". Deseret News. 
  9. ^ "Bingham slide could cut output by 110,000 ST". Mining Engineering. April 17, 2013. 
  10. ^ http://www.deseretnews.com/article/865586245/Movement-at-Bingham-Canyon-Mine-stops-operation-evacuates-100-employees.html?pg=all
  11. ^ Bon, R.L.; Krahulec, K.A. (May 2006). Utah, Mining Engineering. p. 117. 
  12. ^ Bon, R.L.; Krahulec, K.A. (May 2007). Utah, Mining Engineering. p. 120. 
  13. ^ "National Energy Foundation’s Out of The Rock" (PDF). Rio Tinto. p. 22. Retrieved May 6, 2010. 
  14. ^ a b c "Kennecott Utah Copper's Bingham Canyon Mine". Utah.com. Retrieved July 11, 2010. 
  15. ^ a b "Bingham Canyon". Global InfoMine. Retrieved July 11, 2010. 
  16. ^ a b Voynick, Steve. "Bingham Canyon Copper: Finding Chalcopyrite at "The Richest Hole on Earth"". Rock & Gem Magazine. Retrieved July 11, 2010. 
  17. ^ "Bingham Canyon extension could extend life of mine to mid-2030s by moving south wall," Mining Engineering, October 2010, p.10.
General
  • Kennecott Utah Copper Mine brochure (distributed to visitors), dated September 2004.

External links[edit]