Garfield Smelters

This page was last updated on June 17, 2022.

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The processes at the smelter were, and continue to be updated and improved on a regular basis. I have read that Rio Tinto's current smelter is the fourth complete smelter to be located on this site, since the original smelter opened in 1906. With each rebuilding, the mine was shut down while the smelter was rebuilt, or vice versa, the smelter was rebuilt while the mine was shut down. The four known upgrade programs were:

1961-1963 -- Complete renovation, including conversion to use natural gas as fuel; production of sulphuric acid added to eliminate sulphur dioxide air and water pollution. The renovation included adding a new rotary car dumper to increase the capacity of dumping rail cars loaded with conentrate from the Magna and Arthur mills, replacing the previous method of using a crane and clam-shell bucket to unload rail cars. The car dumper and associated conveyor belt system went into operation in April 1962.

1974-1978 -- Kennecott completed several upgrades and improvements as part of a program to address smoke emmissions to comply with new clean air regulations. These included adding a new 1200-foot smoke stack, completed in November 1974.

1995-1997 -- Complete rebuild Garfield smelter included a flash smelting process to allow Kennecott to process all of its concentrate; smelter operated at reduced capacity until 1997 as the new process was fully adopted.

American Smelting & Refining

Utah Copper completed their Copperton mill in April 1904, and commenced operations in September, shipping its low grade ore from the mine to the Copperton mill, by way of the Copper Belt and the Rio Grande Western. (Arrington: Richest Hole, p. 39; Kennecott's own Historical Index says that operations commenced on July 1, 1904)

April 29, 1904
Utah Copper was reorganized as a New Jersey corporation. This new company was organized to provide the finances necessary for further expansion of both mining operations, and milling operations, assuming that the experimental mill at Copperton would be successful. (Kennecott Historical Index)

Until June 1907, all of the ore came from Utah Copper's underground mine. The concentrates from Utah Copper's Copperton mill were shipped to the Bingham Consolidated smelter at Midvale, by way of the RGW.

The expansion of Utah Copper's operation came from the Guggenheims, who also held majority interest in Standard Oil. One of their investment vehicles, the Guggenheim Exploration Company, provided the funding for Utah Copper to build its new mill at Magna, and the reorganization of Utah Copper in April 1904 was the result of the influx of Guggenheim money. The Guggenheims were also the majority owners of American Smelting & Refining (ASARCO), who had bought majority interests in most of the Salt Lake Valley smelters, wanting to consolidate the smelting operations in one large location to benefit from economies of scale that such an operation would provide. To tie their two new properties together, i.e., funding the expansion of Utah Copper, and consolidating the Utah smelters into a new large smelter at Garfield, Utah Copper signed a 20-year contract with ASARCO that would both guarantee a market for Utah Copper mining operations, and through their new mill at Magna, provide copper concentrates for the new Garfield smelter. (Arrington: Richest Hole, p. 46)

Construction of the Garfield smelter began in August 1905. (Salt Lake Mining Review, September 15, 1914, page 14; "The Garfield Plant of the Garfield Smelting Company", article with photographs.)

Construction on the new Utah Copper mill at Magna began in November 1905. (Engineering and Mining Journal, March 17, 1906, p. 534; See also: Arrington: Richest Hole, p. 50)

The Garfield Smelting Company was incorporated and formally organized on November 17, 1905, as a subsidiary of the American Smelting & Refining Co. (Utah corporation files, index 5411)

The Garfield smelter began operations in August 1906. (Arrington: Richest Hole, p. 47)

The Garfield smelter was to start operations "this week". (Salt Lake Mining Review, June 15, 1906, page 32)

News item about the agreement between American Smelting & Refining Company, Utah Copper Company, and Boston Consolidated for the processing of ores at the new Garfield smelter. (Salt Lake Mining Review, August 30, 1906, page 28)

December 13, 1916
Asarco's new sulphuric acid plant at its Garfield smelter began operations. (Box Elder News, December 15, 1916)

Asarco began recovering sulphuric acid from the smelter gases at the Garfield smelter.

December 18, 1934
A large brick smokestack at the Garfield smelter complex were demolished. The smokestack that was demolished was 28 years old, and had been unused since a new 407-feet tall concrete smokestack was erected. (Salt Lake Tribune, December 19, 1934; Ogden Standard Examiner, December 19, 1934)

(This later 407-feet tall concrete smokestack was replaced in 1974 by a new much taller (1,1100 feet) smokestack.)

Utah's three big smelters at Murray, Midvale, and Garfield were closed by a 150-day strike that was settled on June 30, 1946. (Murray Eagle, June 20, 1946)

5,605 tons of concentrate from Magna and Arthur were shipped to Kennecott's smelter in McGill, Nevada due to a one and a half day, and another five day strike at the American Smelting and Refining Company (ASARCO) smelter at Garfield, Utah. (Kennecott Historical Index)

July 1953
The following article about Western Pacific's use of slag ballast comes from the July 1953 issue of Mining Engineering magazine, page 661:

A modern slag crushing and screening unit has been installed at the edge of the slag dump at American Smelting & Refining Co.'s Garfield Smelter to facilitate treatment of slag, found extremely useful as ballast on western railroad grades.

Slag has become popular as ballast because of its excellent drainage characteristics which lead to longer tie life. It also provides a more rigid roadbed than other materials. It has led to a brand new activity at Garfield. Some 30 million tons of slag are already in the dump, with monthly additions of 50,000 tons adding up to what appears to be an inexhaustible supply.

The crushing and screening unit was installed by Utah Sand and Gravel Co., independent contractors. Asarco granted additional right-of-way for the slag treatment plant and necessary service spurs to the Western Pacific Railroad. Western Pacific is the present ultimate purchaser of the slag which is used for an extensive modernization program. The slag is employed for ballast on the main line.

Dumping of the molten slag takes place around a major part of the dump's roughly circular periphery. The treatment plant had to be located where future dumping would not take place. A means for removing the solid slag from the interior of the dump had to be provided without interfering with present haulage or undermining existing trackage and other facilities.

Slag is partially broken up with a modern scarifier and bulldozed to a loading point where a shuttle feeder places it on a conveyor belt. The conveyor transports it under the slag haulage track to the crushing and screening plant. A jaw crusher and a cone crusher give the desired size reduction.

The two-step process for size reduction minimizes the production of fines, a limited-use byproduct. Slag is water-treated before crushing to eliminate dusting during preparation and loading. Vibrating screens remove undersize from the crusher feeds as well as fines from the finished product. The prepared ballast is -1-1/2 +3/8 in. in size. The -3/8 size is being stockpiled at present, but there is hope that someday it may be used for road surfacing and concrete aggregate.

The finished product is lowered to the loading level by means of a rock ladder. The rock ladder is an enclosed tower with projecting shelves alternating on opposite sides, preventing material falling far enough to create further reduction. Present capacity of the plant is 240 tons of prepared slag per hour. The plant is operated five days per week.

Slag is eventually loaded into Western Pacific Railroad hopper cars for transportation to points of use. Western Pacific and Asarco have both benefited from development of this new byproduct.

(View Photo 1)

(View Photo 2)

Until 1959 the Garfield smelter was owned and operated by American Smelting Refining & Mining, and D&RGW provided common carrier acces to Kennecott's Utah Copper Division and other mining companies that sent their ore to Asarco to be processed. In 1959, Kennecott bought the smelter and took over operations, at which time the railroad became Kennecott's in-plant railroad, with D&RGW having limited trackage rights to allow limited common carrier access.


January 2, 1959
Kennecott Copper Corporation took over operation of the Garfield smelter of American Smelting and Refining Company (Asarco). The purchase took effect on January 1, 1959. The sale price was reported as $20 million. The smelter had an annual input capacity of concentrates and ore of 1,608,000 tons, but was processing 625,000 tons annually. At the same time, Kennecott ended Asarco's practice of accepting ore from other mines, and the Garfield smelter would no longer be what was known as a custom smelter. In the months prior to the sale, Asarco was purchasing 10,000 to 15,000 tons per month from other mines, including independent producers in the Park City and Eureka districts. (Salt Lake Tribune, January 1, 1959)

Mid 1961
The new acid plant oof the Garfield Chemical and Manufacturing company went into operation. A joint venture of Kennecott and American Smelting, the plant was capable of of producing 1000 tons of sulphric acid each day. The acid was from sulphur dioxide gases that were being removed from the smelter exhaust gases and waste water as part of the overall cleanup up of environmental issues. Customers for the sulphuric acid included Kennecott for use in its newly expanded leaching operations at the Bingham mine, along with the production of fertilizer by Western Phosphate at its new plant recently completed about a mile north of the smelter site.

Improvements at the Garfield smelter included natural gas as fuel in the furnaces, replacing pine poles used in the roasting furnaces. The roasting process was used historically to allow the custom smelting of ore from other mines other than the Bingham copper mine. The new smelting processes ended the roasting of metal ores, and using direct feed of concentrates into the furnaces. Also, a car dumper was installed to replace the use of a crane to unload rail cars. (Salt Lake Tribune, February 25, 1962)

The pine poles were coming from a company based in Price, Utah, that shipped "green" pine poles to Kennecott. Kennecott in-turn used 15 tons of pine poles daily as part of its smelting process. (Price Sun-Advocate, October 18, 1962)

A molybdenum oxide production plant was placed in operation at the Garfield smelter.

(See also: Kennecott article in Utah History Encyclopedia)

June 21, 1974
Work began on the concrete pour for the base of the new smokestack at the Garfield smelter. The pour lasted from June 21st at 6pm to late evening of June 23rd. The base measures 177 feet across by 12 feet thick at it center. (Magna Times, June 27, 1974)

November 17, 1974
Kennecott completed the construction of the new smokestack at its Utah smelter. Construction started on August 26, 1974. At 1,115 feet high, the smokestack is the tallest man-made structure in Utah, as well as the tallest free-standing structure west of the Mississippi. The extra height was needed to meet the requirements of the Clean Air Act of 1970, to disperse waste gases according to the new standards. The new smokestack replaced several earlier smokestacks, the tallest of which was 413 feet high. The old smokestacks were demolished upon completion of the new smokestack. (Deseret News, November 15, 2009, upon the 35th anniversary of the completion of the smokestack)

Kennecott completed several upgrades and improvements as part of a program to address smoke emmissions to comply with new clean air regulations. These included adding a new 1200-foot smoke stack, completed in November 1974. The upgrades and changes to the smelter were completed in 1977 and 1978.

New smelter went on line in 1977-1978. (Salt Lake Tribune, March 2, 1980)

June 1991
The two 400-foot smoke stacks that the new 1200-foot smoke stack replaced, were demolished in June 1991. (Salt Lake Tribune, February 14, 1993)

Plans were also made for the construction of a new $880 million smelter west of Salt Lake City. It was hoped that the new smelter would enable Kennecott to process all of its own concentrate, rather than send 40 percent elsewhere to be refined. ( - Kennecott History)

The following comes from a report completed in 1999:

The new Kennecott Utah Copper smelter, started in 1995, was designed to be the cleanest smelter environmentally in the world. The plant is operating at production rates above the original design capacity. Copper concentrate is smelted in an Outokumpu flash smelting furnace. Matte is granulated and processed using Kennecott-Outokumpu flash converting. Copper anodes are processed in a modernized copper refinery using the Kidd Process.

Kennecott Utah Copper Corporation (KUCC) expanded its mine and mill facilities in 1988 increasing the production rate to 773,000 tonnes per year of copper concentrate. A further expansion of the mill in 1992 raised the concentrate production to 1.0 million tonnes per year. The smelter facilities could only process about half this tonnage primarily because of insufficient acid plant capacity to meet increasingly restrictive air emission regulations. The remaining concentrate production was sold.

In 1989, KUCC initiated a study of smelting requirements to process all of the available concentrate resulting from the current expansion of mining and milling facilities and also possible future expansions. As a result of this study, the Outokumpu flash smelting furnace was chosen as the primary smelting vessel, to be coupled with Kennecott-Outokumpu flash converting technology to process solid matte through to blister copper. ("Recent operation and environmental control in the Kennecott Smelter," ca. 1999)

The following comes from the September 2000 issue of Utah Economic and Business Review

The new Outokumpu flash smelter came online in 1995, at a cost of $880 million. The new smelter had increased capacity over the Noranda smelter installed during the 1970s and more effective pollution control equipment. Prior to installing the Outokumpu smelter, Kennecott was exporting approximately 40 percent of the copper concentrate produced. The new smelter allowed for all of the concentrate produced at Bingham Canyon to be smelted in Utah and cut sulfur dioxide emissions by 96 percent.

The first large capital investment made by Kennecott in the Bingham Canyon Mine over the past three decades was to replace the original reverberatory smelter with a Noranda smelter in the 1970s. The project was completed in 1978 and cost $280 million.

April 1995
Kennecott's 300,000-tons-per-year copper smelter had been completed by mid April 1995 and began its testing phase, with limited production expected to begin in May. When full production starts, in June or July, the old smelter will be demolished. The old smelter used old technology that used open blast furnaces to convert copper concentrate to copper matte, using large overhead cranes and ladles to move the molten copper matte from the furnaces to cast the copper matte into anodes, which were then transported by rail car to the refinery. The new smelter would reduce smelter operating costs by 53 per cent, and changes to the refining process would reduce refining costs by 45 per cent. The resulting copper would be 99 per cent pure. The modernization of the smelter and refinery would allow Kennecott to process all of the copper ore being produced by the Bingham Canyon mine. (Salt Lake Tribune, March 22, 1995; April 16, 1995)

Problems getting the various parts of the new and complex smelting process to work together, forced the smelter to operate at 80 to 85 percent capacity until early 1997. The reduced capacity meant that Kennecott had to sell come of its copper concentrate to other smelters, and to begin stockpiling concentrate pending the smelter's return to full capacity. The new smelter had been commissioned in July 1995. (Salt Lake Tribune, September 13, 1996)

September 21, 1995
Kennecott held a dedication ceremony to make the completion of the new smelter, which had begun full production, with full capacity to be reached in the first quarter of 1996. The new smelter was the lowest cost copper smelter in the world, and set a new standard by using two newly developed processes. The first, known as flash smelting, was more efficient and cleaner that the former method. The new smelting process also used water to quench the molten copper after it had been smelted from copper concentrate, forming pellets that were easier to transport than the previous method in which molten copper in ladles were transported by large overhead cranes. The second process was known as flash converting, and allowed the smelter's pollution controls to operate more efficiently, with lower emissions by capturing 99.9 per cent of the sulfur generated by the smelting process. (Deseret News, September 21, 1995)

Flash smelting produced copper matte that is 70 percent pure; flash converting further converted copper matte to blister copper, which is 98.6 percent pure. (Deseret News, February 5, 1999)

Flash smelting was developed in the late 1940s by the Finnish state's copper company, Outokumpu, which needed needed electricity to refine metal, but there was a shortage of electricity in Finland. A solution was found that used the sulfur present in the ore to flash the impurities. This produced a copper matte product that was almost 80 percent pure copper. The process used at Kennecott Utah's Garfield smelter modified the Outokumpu process by using an additional flash process, a "double-flash," that produced blister copper that are processed to become anodes that are 99 percent pure copper. 

February 1997
The problems with getting the new smelter fully operational drove RTZ profits down 23.9 per cent, from $1.4 billion in 1995, to $1.1 billion in 1996, about half due to falling metals prices, and about half due to delays concerning the new smelter. The new smelter was expected to be fully operational by June 1997. (Salt Lake Tribune, February 28, 1997; Salt Lake Tribune, March 20, 1997)

May 27, 1997
Kennecott's new smelter was re-started after a six-week shutdown. Production was about 100 tons of copper anodes per hour, with each anode weighing 720 pounds, and being 99.5 percent pure copper. The anodes were then transported to the Utah refinery, where the copper was further refined to be 99.99 percent pure. (Salt Lake Tribune, June 12, 1997; Salt Lake Tribune, July 31, 1997)

During a tour of the smelter in 2014, with the smelter's director as a tour guide, the tour group were shown the operation that received copper concentrate by rail from several concentrators all over the western U.S.When asked where the concentrate was coming from the director provided comments about the business of buying copper concentrate on the open market. At the time in 2014, about six months after the slide in Bingham that shut the mine down, it was cheaper to buy the concentrate from other suppliers than for Rio Tinto to furnish it from its own Utah operation. The Utah smelter was apparently run as its own business unit.

The smelter director also mentioned that the current smelter was the fourth version that had been built on the Garfield site, meaning that the smelting process had been completely changed three times, with all the changes and upgrades completed to increase the efficiency of the smelting process. Each version was a rebuild of the previous one. The technology of getting metals from the concentrate is almost constantly changing and improving, to lower costs and reduce environmental problems. At the time, in 2014, it was the largest and most efficient copper smelter in the world, competing and regularly changing places with three others as they each improve their processes. Even in 1908, the Garfield smelter was one of the largest in the world.