The Morenci Mine is a large

copper mine Copper extraction is the multi-stage process of obtaining copper from its ores. The conversion of copper ores consists of a series of physical, chemical, and electrochemical processes. Methods have evolved and vary with country depending on the ...

located near

Morenci, Arizona Morenci is a census-designated place (CDP) and company town in Greenlee County, Arizona, United States, and was founded by the Detroit Copper Mining Company of Arizona. The population was 2,000 at the 2000 census and 1,489 at the 2010 census ...

, United States. Morenci represents one of the largest copper reserves in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

and in the world, having estimated reserves of of ore grading 0.16% copper. It is located in

Greenlee County Greenlee County is a county in the southeastern part of the U.S. state of Arizona. As of the 2020 census, the population was 9,563, making it Arizona's least populous county. The county seat is Clifton. The economy of Greenlee County is d ...

, just outside the company town of Morenci and the town of Clifton.

Freeport-McMoRan Freeport-McMoRan Inc., often called Freeport, is an American mining company based in the Freeport-McMoRan Center, in Phoenix, Arizona. The company is the world's largest producer of molybdenum, a major copper producer and operates the world's la ...

is the principal owner and, since 2016,

Sumitomo Group The is a Japanese corporate group and ''keiretsu'' that traces its roots to the ''zaibatsu'' groups that were dissolved after World War II. Unlike the ''zaibatsu'' of the pre-war period, there is no controlling company with regulatory power. In ...

has owned a 28% interest in the mine.

Production

In 2016, copper production at Morenci was . In 2017, copper production at Morenci was . 3,300 people were employed there. As production declined, it was estimated in 2023 that the mine would be exhausted in 20 years. The mine is served by the Freeport-McMoRan Industrial Railroad, which interchanges with

Arizona Eastern Railway The Arizona Eastern Railway is a Class III railroad that operates of railroad between Clifton, Arizona, and Miami, Arizona, in the United States. This includes trackage rights over the Union Pacific Railroad between Lordsburg, New Mexico, and ...

in Clifton. The railroad is used to bring chemicals (primarily

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, ...

) to the mine, as well as ship out copper concentrate.

History

The mine was established as an underground mine in 1871 by the Longfellow Mining Company and was converted into an

open-pit mine Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining, is a surface mining technique that extracts rock or minerals from the earth. Open-pit mines are used when deposits of commercially useful ore or ...

by the

Phelps Dodge Corporation Phelps Dodge Corporation was an American mining company founded in 1834 as an import-export firm by Anson Greene Phelps and his two sons-in-law William Earle Dodge, Sr. and Daniel James (businessman), Daniel James. The latter two ran Phelps, Jame ...

starting in 1937. The earliest operations at Morenci Mine, then called the Longfellow Mine, used

mule The mule is a domestic equine hybrid between a donkey, and a horse. It is the offspring of a male donkey (a jack) and a female horse (a mare). The horse and the donkey are different species, with different numbers of chromosomes; of the two ...

s to transport ore carts. In April 2012, the

U.S. Department of Justice The United States Department of Justice (DOJ), also known as the Justice Department, is a federal executive department of the U.S. government that oversees the domestic enforcement of federal laws and the administration of justice. It is equi ...

announced that Freeport McMoran agreed to pay $6.8M to settle federal and state charges pertaining to the outflow of acidic metal bearing waters from the Morenci Mine. According to the complaint, waters, soils, habitats, and birds were either injured or lost as a result of the hazardous substances. MorenciMine1

Labor Disputes

The Morenci Mine has had a long history of labor disputes between mine workers and the various companies that have operated it. One of the earliest strikes at Morenci was in 1903, when workers, who were predominantly of Mexican descent and not represented by a union at the time due to racial issues, went on strike for higher wages. The strike ended when a flash flood destroyed many of the miners' homes and caused 40–50 deaths, prior to an anticipated confrontation between strikers and the

U.S. Cavalry The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 states and a federal capital district, Washington, D.C. The 48 contiguou ...

. The Morenci Mine was also central in the historic Arizona mine strike of 1983. From 1983 to 1986, workers at Morenci and three other mines went on strike due to layoffs impacting most of the workers at the mine following a large drop in the price of copper. Following the hiring of

strikebreaker A strikebreaker (sometimes pejoratively called a scab, blackleg, bootlicker, blackguard or knobstick) is a person who works despite an ongoing strike. Strikebreakers may be current employees ( union members or not), or new hires to keep the orga ...

s by Phelps-Dodge, striking union workers blocked the entrance to the mine, and engaged in sometimes violent confrontations with the strikebreakers. The early days of the strike involved large-scale armed intervention from the

Arizona National Guard The Arizona National Guard is the National Guard of the American state of Arizona. It consists of the Arizona Army National Guard and the Arizona Air National Guard. Both components are part of the Arizona Department of Emergency and Milit ...

and Department of Public Safety, including armored vehicles and sharpshooters. In 1984, workers at Morenci began voting to decertify the unions, which resulted in the largest union decertification in the United States. The strike of 1983 completely failed in 1986 after the

NLRB The National Labor Relations Board (NLRB) is an independent agency of the federal government of the United States that enforces U.S. labor law in relation to collective bargaining and unfair labor practices. Under the National Labor Relations ...

rejected appeals by the unions to halt the decertification. MorenciMine4

References

External links

Morenci Copper Mine
at Geology for Investors, June 16, 2021 {{Freeport-McMoRan, state=collapsed Copper mines in Arizona Freeport-McMoRan mines Geography of Greenlee County, Arizona Open-pit mines