Bingham Canyon Mine


The Bingham Canyon Mine, more commonly known as Kennecott Copper Mine among locals, is an open-pit mining operation extracting a large porphyry copper deposit southwest of Salt Lake City, Utah, in the Oquirrh Mountains. The mine is the largest human-made excavation, and deepest open-pit mine in the world, which is considered to have produced more copper than any other mine in history – more than. The mine is owned by Rio Tinto Group, a British-Australian multinational corporation. 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 deep, wide, and covering. It was designated a National Historic Landmark in 1966 under the name Bingham Canyon Open Pit Copper Mine. The mine experienced a massive landslide in April 2013 and a smaller slide in September 2013.

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, Latter-Day Saint 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 were of paramount importance at that time. The brothers applied 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.
Bingham mine was part of the historical West Mountain Mining District. It was not until September 17, 1863, with the organization of mining districts in the state of Utah, that extraction of ore began, and the potential of the canyon's mineral resources began to be widely recognized. The first claim located was "Jordan S.M.Co" on September 17, 1863, the day the district was organized.
Soon followed were other mining claims, including Galina and Independence in 1864, and Buckeye and Spanish in 1865. George B. Ogilvie and 23 others located the West Jordan claim in 1870. At first, mining was confined to placer gold, lead-silver, and copper-gold. Porphyry copper required processing and a railroad, which reached the canyon in 1873.
Enos Andrew Wall started working claims in 1887. His extensive tunnels and test pits, on his, indicated ore containing 2% copper.
The canyon's 19th Century mines were relatively small, and it wasn't until the end of the century that very large-scale exploitation of the canyon's ore bodies began to develop with open-pit mining. In 1896, Samuel Newhouse and Thomas Weir acquired the Highland Boy Mine, which was rich in copper, silver, and gold. Together they formed the Utah Consolidated Gold Mines, Ltd. with English investors. They then formed the Boston Consolidated Gold and Copper Co., Ltd., for the development of low-grade copper ore adjacent to the Utah Copper Company site.
Another 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 ore body at Bingham Canyon was based on Jacklin's 1904 decision to use open-pit mining, steam shovels, and the railroad. The mine became a showplace for "railroad-pit operations," and the industrial complex defined by the mine and the ASARCO smelting operation made it the "largest industrial mining complex in the world" by 1912.
Utah Copper and Boston Consolidated merged after their separate surface operations approached each other in 1906. The Kennecott Copper Corporation, established to operate mines in Kennecott, Alaska, purchased a 25 percent financial interest in Utah Copper in 1915, which increased to 75 percent in 1923.
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, and several of the mining camps were 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.
The 21 separate mining operations in existence by 1911 were consolidated into two in 1970: Kennecott and The Anaconda Minerals Company. In 1985 open-pit mining operations were halted by Kennecott's Utah Copper. In 1986, Kennecott discovered gold in nearby Barney's Canyon.
KCC was purchased by Sohio in 1981, and the mine reopened in 1987 after BP Minerals purchased the assets. In 1989 the Rio Tinto Group acquired the asset, which modernized the mine, mill, and smelter.
The open-pit owners replaced an antiquated 1000-car railroad with conveyor belts and pipelines for transporting the ore and waste, which reduced costs by nearly 30% and returned the operation to profitability.

Landslides

At 9:30 pm on April 10, 2013, a landslide occurred at the mine. Around of dirt and rock thundered down the side of the pit. It is possibly the largest historic non-volcanic landslide in North America. On the basis that the mine's steep walls made it a high risk for landslides, an interferometric radar system had been previously installed to monitor the ground's stability. As a result of warnings produced by this system, mining operations had been shut down the previous day in anticipation of the slide and there were no injuries. The massive slide was expected to cut production of mined copper by. A second slide caused an evacuation of 100 workers on September 11, 2013. Another, less severe slide occurred on May 31, 2021.

Environmental history

Similar to other industrial age mining operations, the mine historically 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. 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, Kennecott 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.
The figure above shows a comparison of two satellite images used to identify the changes in the Bingham Canyon Mine between 1985 and 2016

Geology

The Bingham Canyon ore deposits occur in the Bingham nappe. They are a porphyry copper deposit, formed by a quartz monzonite porphyry intruded into sedimentary rocks. They exhibit a concentric alteration pattern and mineralogic zonation around the Bingham stock. These zones include a central core containing magnetite, followed by "a molybdenite zone low in copper, a bornite-chalcopyrite-gold higher grade copper zone, a pyrite-chalcopyrite zone, a pyrite zone, and an outermost lead-zinc zone."
Structurally, Late Paleozoic rocks were thrust faulted over the Precambrian craton during the Cretaceous Sevier orogeny. These rocks were later intruded and altered in the Tertiary by granitoid rocks. This igneous event was the source of deposition of gold, silver and other base metals.
Copper and molybdenum sulfide minerals are dispersed in the intruded stock and in the adjoining carbonate sedimentary skarns. The main stratigraphic rocks in Bingham Canyon are Upper Pennsylvanian sandstones, quartzites, and limestones known as the Bingham Mine Formation in the Oquirrh Group. The central porphyry ores formed from mantle hydrothermal circulation while the outer vein and deposits in the sedimentary rocks formed at lower temperature when magmatic and meteoric waters mixed.

Recovery process

The extracted ore is treated at the Kennecott smelter at nearby Magna, Utah. The ore is run through a concentrator, where 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 from the chalcopyrite.
The filtered concentrate slurry is piped 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 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.

Operations

Kennecott's Bingham Canyon Mine is the largest artificially made excavation in the world, and is visible to the naked eye from an orbiting space shuttle. Employing some 2,000 workers, of material are removed from the mine daily. Electric shovels can carry up to or of ore in a single scoop. Ore is loaded into a fleet of 64 large dump trucks which each carry of ore at a time; the trucks themselves cost about $3 million each. There is a series of conveyors that take ore to the Copperton concentrator and flotation plant. The longest conveyor is long.
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. It is one of the top producing copper mines in the world, with production at more than 18.7 million short tons. Every year, Kennecott produces approximately 300 thousand short tons of copper, along with 400 thousand troy ounces of gold, 4 million troy ounces of silver, about 10 thousand short tons of molybdenum, and about a million short tons of sulfuric acid, a by-product of the smelting process. Rio Tinto purchased Kennecott Utah Copper in 1989 and has invested about $2 billion in the modernization of KUC's operations.