Kennecott's North Ore Shoot

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This page last updated on June 8, 2024.

Overview

Three Shafts

This research is mainly to document the purpose of the three headframes visible in photos at Bingham:

the Anaconda exhaust shaft of 1975-1982
the first North Ore Shoot shaft of 1978-1993
the later North Ore Shoot shaft of 2007 to today

In September 2011 Kennecott announced in a press release that work was to resume in the development of the North Ore Shoot gold and copper skarn, the underground expansion project for Kennecott Utah Copper's Bingham mine. The ore body is about 1000 feet below the current bottom of the Bingham open pit mine, and the North Rim Skarn project would involve the construction of an underground mining facilities, including new vertical shafts and horizontal drifts and galleries and declines, as well as refurbishing an existing shaft. Most of the work would be contracted out.

(A "skarn" is the area between host waste rock and mineralized ore rock, and can usually be mined due to high concentrations of minerals. At Bingham, the skarn being developed was about 2-1/2 to five times as rich as the ore currently being extracted by open-pit methods. But the high cost of underground mining made development and extraction unprofitable.)

What is known as the North Ore Shoot is high-grade copper and gold mineralization in limestone formations that are a down-dip extension of the Carr Fork mineralization that Anaconda had previously tried to mine with its Carr Fork Project in 1974-1982. The grade of the ore in the North Ore Shoot is about three times the similar mineralization previously seen in the former Anaconda ground.

(View a brief timeline of Anaconda's Carr Fork Project, below)

In the early 1980s, Kennecott sank a shaft about 3000 feet deep and completed limited metallurgical sampling, as well as limited mining to test underground mining methods. The sampling and test mining methods found that although the ore itself is high grade, the cost of actual mining was high, meaning that the economics look good when copper and gold prices are high, but only marginal when they are low.

Exploration for the North Ore Shoot in 1980-1981 was in response to the adjacent development work being done by Anaconda as part of its Carr Fork Project. The North Ore Shoot exploration began with a headframe and vertical shaft located adjacent to the main highway in Bingham canyon in the middle of the old Bingham town site, on the south side and a bit down-canyon from the new 6190 rail yard which had been completed in 1978. The headframe for the exploration and development work is visible in a photo taken in June 1981.

The ore bodies of the North Ore Shoot are part of what was known as Bingham Canyon's deep copper-gold skarn along its northern boundaries. Anaconda had discovered the skarn ore body in 1969 and began development in late 1974, with production starting from the new mine in 1979.

Kennecott held claims to adjacent to the Anaconda ore bodies and began drilling its own exploration holes. Kennecott's own underground development began in the late 1970s with what it called its "North Ore Shoot Extension." The new headframe was in place by August 1978.

Kennecott's exploration continued as Anaconda developed what it called its Carr Fork Project. The Anaconda project shut down in 1982 due to Anaconda's financial difficulties with its world-wide operations. In late 1984 Kennecott and Anaconda announced a joint venture to develop the skarn ore body, and in late 1985, Kennecott purchased all of Anaconda's interest in its mines and claims in the Bingham district.

After 1985-1986 the vertical shaft accessing the North Ore Shoot, along with the former Anaconda Carr Fork mine (sold to Kennecott in 1985), were abandoned and allowed to flood. The shaft was sealed at the top and the headframe was removed. The site was used as part of the overall waste rock dumping grounds.

In 2007-2008 Kennecott began work to have a contractor recover the original North Ore Shoot vertical shaft, connecting a new top-of-shaft collar with the existing vertical exploration shaft from the 1980-1981 period. The newer headframe and hoist were in the same location as the previous headframe and hoist that had been removed to allow nearby waste-rock dumps to be expanded. The new headframe was completed in 2008 and was about 230 feet higher, on the same vertical shaft.

The new vertical shaft was 28 feet in diameter and connected the new shaft collar with the old shaft collar, 240 feet below. The old shaft was 20 feet in diameter, and was previously completed to a depth of 3,089 feet in 1983. The copper and gold deposit had been initially explored in the early 1980s with 12,300 feet of horizontal tunnels, known as "drifts," along with continuing to drill exploration holes.

The recovery of the North Ore Shoot vertical shaft in 2007-2008 included a new headframe, which, as of June 2021, remained on the site near the 6190 truck shop, and adjacent to the new pit crusher completed in 2021.

Underground operations are progressing into 2024, with production planned for later in 2024 or early 2025.

Timeline

1957
By using exploration drilling, Kennecott discovered the North Ore Shoot in 1957, but the full extent of the ore body was not yet known, and current open pit mining operations remained as the focus of the company.

1978
The headframe for the North Ore Shoot project was in place at the time of photos dated August 1978 (based on processing dates of color slide photographs), but there were no support buildings adjacent to the head frame.

September 1980
Work began on the North Ore Shoot Extension, mining ore for the production of copper, gold, silver, and molybdenum. A study completed in 1980 projected that the Bingham Mine would have to convert partially to underground operations and build new concentrators. Development of the North Ore Shoot included a new headframe and hoist house, and a 4200-foot vertical shaft, together with underground "service stations." The construction of the vertical shaft and attendant surface structures, including a large headframe and hoist house, was contracted to Harris & Western of Denver. At a reported cost of $30 million, the contract was to last for five years, until 1985. (Salt Lake Tribune, November 19, 1980; March 18, 1981)

The contractor for the North Ore Shoot development project in the 1980-1984 period was Harrison-Western.

1981
Photos from mid 1981 show a large variety of support buildings in place, indicating that the site was active.

"Development of the so-called North Ore Shoot Extension, a high-grade deposit of copper, gold, silver and molybdenum several thousand feet under the northeast shoulder of the Bingham pit, began in September. A 4,200-foot shaft is being sunk to press development of the North Ore Shoot." (Salt Lake Tribune, March 18, 1981)

March 14, 1981
The sale to Sohio would give Kennecott access to financial reserves needed to modernize all of its copper properties in Utah, Nevada, New Mexico and Arizona, including developing a recently discovered high-grade body in Utah known as the North Ore Shoot Extension. Kennecott had been seeking to develop this new ore body through a joint venture with Fluor Corporation. (New York Times, March 14, 1981)

March 8, 1981
"Development of the so-called North Ore Shoot Extension, a high-grade deposit of copper, gold, silver and molybdenum several tousand feet under the northeast shoulder of the Bingham pit, began in September [1980]. A 4,200-foot shaft is being sunk to presss development of the North Ore Shoot." (Salt Lake Tribune, March 18, 1981)

1983
The North Ore Shoot of the 1980s had a subsurface depth that reached a maximum of 4,265 feet. Mine capacity in 1983 was 12,125 tons per day.

July 1984
Because the North Ore Shoot was a joint venture with Fluor Corporation, development was separate from the overall open pit operations, and did not shut down in July 1984 at the same time as other parts of Kennecott's Utah operations. The formal name for the underground development during the early 1980s was separate and was the Kennecott Copper and Gold Mining Co.

November 1, 1984
Kennecott and Anaconda announced a joint venture that would resume production from Anaconda's Carr Fork underground mine. Kennecott was to be the operator and would receive 96 percent of the production, with Anaconda receiving the remaining four percent. The Carr Fork concentrator had a 10,000 tons per day capacity, but the mine never reached that number in its production. (Deseret News, November 2, 1984)

The company that was created was a joint operating agreement for the New Bingham Mary Mining Company, a mining claim located at the northwest corner of Kennecott's Bingham open pit copper mine. The New Bingham Mary property was along Kennecott's shared boundary with The Anaconda Company's property at Bingham, which also touched Kennecott's property at several spots along the property line.

1985
Kennecott bought Anaconda's interest in the joint New Bingham Mary project in October 1985.

1986
The joint project of the North Ore Shoot with Fluor was reported as being abandoned, the pumps turned off, and the shaft was allowed to flood.

September 13, 1990
Kennecott's North Ore Shoot project was still being developed, but the high cost of underground mining was deterring any action beyond continued development work. (Salt Lake Tribune, March 18, 1990)

1993-2006
Aerial photos from 1993 show the North Ore Shoot headframe still in place. By 2005 aerial photos show that the headframe had been removed and the area had been reconfigured as waste rock dumping grounds. By the end of 2006 the area was being used for storage of machinery and equipment.

1998-2001
In June 1998 Kennecott began pumping water from the North Ore Shoot shaft, preparing to resume development work. By 2001, the pumps were removing 1,100 gallons per minute. With the bottom of the North Ore Shoot shaft being over 1,000 feet below the bottom of the open pit mine, the pumping had the added benefit of dewatering the bottom of the pit itself. A year later, in July 1999, Kennecott began pumping water from the bottom of the former Anaconda Carr Fork mine. By 2001, the Carr Fork pumps were removing 1,500 gallons of water per minute.

2008
Contractors completed the recovery of the North Ore Shoot. In 2007 Kennecott Utah Copper contracted with Atkinson Construction LLC of Golden, Colorado, at a reported cost of $44.5 million, to recover its North Ore Shoot vertical shaft that was built in the early 1980s but had since been capped, backfilled, and abandoned at the end of the five-year development period in 1985. In 2007, to uncover the old shaft, crews excavated a 230-foot-deep, 28-foot-diameter shaft through unconsolidated waste rock fill to an existing heavily reinforced concrete shaft collar.

Once the recovery of the vertical shaft was complete, Atkinson installed a new shaft collar and concrete liner throughout the new excavation, removed the existing shaft collar and dewatered the 3,300-foot-deep, 20-foot-diameter shaft. Late in 2007 the scope of work expanded to include a permanent headframe structure, construction of all surface infrastructure, and a complete retrofit of the underground facilities. The project included the installation of a dirty water pumping system, steel shaft lining, a ventilation system, and development of underground stations.

The new headframe is a hybrid headframe, supporting both a tower-mounted friction hoist, for service and maintenance, and two drum hoists, one for production and the other as an auxiliary.

In 2011 additional rehabilitation work was begun, including upgrading the utilities and steel shoring in the original 1980s shaft down to the 4500 level (4,500 feet above sea level), which was brought up to current standards. An additional 7,000 feet of drifts were begun to support additional feasibility studies.

(With the shaft collar being the the mine's 6190 level, the above mentioned shaft depth, down to the 4500 level, indicates that the rehabilitated shaft was 1,690 feet deep. As of mid 2023, the bottom of the open pit mine was at about 4600 feet above sea level.)

(As of early June 2024, the current pit bottom is just under 4000 feet elevation. The underground portals are at 4590, and the main workshop, crusher, and North Ore Shoot Shaft are at 6190.)

The work to rehabilitate the North Ore Shoot shaft came to an end in 2014, and the reseources (men, equipment, funding) were diverted to recover from the Manafay slide that had occurred in April 2013. Although the headframe and surface buildings are still in place, as of June 2021, the project was in suspended status.

July 22, 2021
Kennecott announced that underground operations would resume. (Rio Tinto press release, July 22, 2021)

September 27, 2022
Kennecott announced the continued development of its underground mineral resources. The offical name of the underground ore body being shown as the Lower Commercial Skarn. (Rio Tinto press release, September 27, 2022)

During 2023 and 2024, development work resumed, with the North Ore Shoot shaft, and headframe on the 6190 level serving both to pump water and as a ventilation shaft. As underground development operations continue, and if production starts, the North Ore Shoot shaft will also be used to move ore to the surface; it is adjacent to the new site of the pit crusher and the conveyor system that feeds the Copperton mill. With the shaft depth being 1000 feet below the bottom of the open pit, the North Ore Shoot shaft continues to dewater of the lowest parts of the open pit part of the Bingham mine.

June 23, 2023
The following selected items come from a June 20, 2023 Rio Tinto press release.

Officials said $498 million of the funding — the largest chunk — will go toward the underground development and necessary infrastructure for an underground area of the mine known as the north rim skarn.

Copper production from the north rim skarn will begin in 2024 — delivering around 250,000 tons of mined copper over the next 10 years alongside open-cut operations.

Going underground will give Kennecott access a different ore body with a different grade of ore.

Copper ore taken from the surface of the Kennecott Bingham open pit mine contains around 0.5% copper per ton, while the copper ore taken from underground varies from 1.5% to 2.5% copper per ton.

In September [2022], Rio Tinto announced a $55 million investment in development capital in a section of its underground copper deposit known as the lower commercial skarns.

Anaconda Carr Fork

September 7, 1974
Anaconda announced a new project to begin mining copper from a new underground mine to be located about two miles west of Kennecott's Bingham open pit mine.

The headframe for the exhaust shaft of Anaconda's Carr Fork mine was located on the Bingham side of the ridge, on a pad situated on the north side of the old Carr Fork county road, about 1,000 feet up-canyon from the Kennecott observation platform. The headframe was not yet in place at the time of a photo taken in June 1975, but was completed by the time of photos taken in August 1975. The headframe was missing in a photo taken the area in October 1982, with the headframe being removed and replaced by an exhaust fan housing.

January 1977
In January 1977, Atlantic Richfield Company (ARCO) purchased the all interests of Anaconda Copper Mining Company.

October 1982
Anaconda closed its Carr Fork underground mine, after just three years of operation.

October 1985
Kennecott purchased all of the Anaconda's interest in the previous joint venture, as well as Anaconda's other properties at Bingham.

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