Anaconda Copper Mine (Nevada)
Encyclopedia
The Anaconda Copper Mine is an open pit
copper
mine
in Lyon County
, Nevada
that was owned and operated by the Anaconda Mining Company
. It is located adjacent to the town of Yerington
. The company town
of Weed Heights
was built to support the mining operation which ran until 1978.
. Atlantic Richfield ceased operations in 1978 due to a low copper prices, lower priced foreign imports of copper and declining grade and resources in the pit. The property was sold in 1982 to Don Tibbals, a Lyon County commission
er. The land was subsequently resold to Arimetco, with the exception of Weed Heights.
ore (from the upper portion of the pit) was processed by heap leaching
, either directly with sulfuric acid
in vats to produce a copper solution precipitated by passing it over scrap iron
, or by leaching successively in acid and kerosene
solutions, subsequently electroplating onto stainless steel
sheets. Copper sulfide
ore from the lower portion of the pit was processed by crushing, and flotation
with calcium oxide
added to the solution to maintain an alkali
ne pH
.
. Since 2000, it has spent approximately $6 million addressing this issue and ARCO
has spent $2.7 million to clean the site. In 2009 ARCO committed to spending $10.2 million for future and past cleanup work. Of the $10.2 million, $8 million is for future work and $2.2 million is to reimburse the EPA for past work completed. In 2008 ARCO reimbursed the EPA $2.7 million.
Open-pit mining
Open-pit mining or opencast mining refers to a method of extracting rock or minerals from the earth by their removal from an open pit or borrow....
copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
mine
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
in Lyon County
Lyon County, Nevada
Lyon County is a county located in the U.S. state of Nevada. As of the 2010 census, the population was 51,980. Its county seat is Yerington.-History:...
, Nevada
Nevada
Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...
that was owned and operated by the Anaconda Mining Company
Anaconda Copper
Anaconda Copper Mining Company was one of the largest trusts of the early 20th century. The Anaconda was purchased by Atlantic Richfield Company on January 12, 1977...
. It is located adjacent to the town of Yerington
Yerington, Nevada
Yerington is a city in Lyon County, located in western Nevada, USA. The population was 2,883 at the 2000 census. It is named after Henry M. Yerington, Superintendent of the Virginia and Truckee Railroad from 1868 to 1910. It is the county seat of Lyon County....
. The company town
Company town
A company town is a town or city in which much or all real estate, buildings , utilities, hospitals, small businesses such as grocery stores and gas stations, and other necessities or luxuries of life within its borders are owned by a single company...
of Weed Heights
Weed Heights, Nevada
Weed Heights is a community in Lyon County, Nevada. It is adjacent to Yerington, Nevada.-History:The Anaconda Copper Company built Weed Heights in the 1950s to support the Anaconda Mine. The town was owned by Anaconda until the company was taken over by Atlantic Richfield Company...
was built to support the mining operation which ran until 1978.
History
The Anaconda Mine first opened in 1918 as the Empire Nevada Mine. In 1953 the property was acquired by the Anaconda Copper Company,which ran the mine until Anaconda was taken over by Atlantic Richfield CompanyARCO
Atlantic Richfield Company is an oil company with operations in the United States as well as in Indonesia, the North Sea, and the South China Sea. It has more than 1,300 gas stations in the western part of the United States. ARCO was originally formed by the merger of East Coast-based Atlantic...
. Atlantic Richfield ceased operations in 1978 due to a low copper prices, lower priced foreign imports of copper and declining grade and resources in the pit. The property was sold in 1982 to Don Tibbals, a Lyon County commission
County commission
A county commission is a group of elected officials charged with administering the county government in local government in some states of the United States. County commissions are usually made up of three or more individuals...
er. The land was subsequently resold to Arimetco, with the exception of Weed Heights.
Production
The Anaconda mine operated for 25 years and produced approximately 360 million tons of material from the pit. Most of the material remains in tailings or in leach heap piles. The copper was processed from the extracted ore using two processes. Copper oxideOxide
An oxide is a chemical compound that contains at least one oxygen atom in its chemical formula. Metal oxides typically contain an anion of oxygen in the oxidation state of −2....
ore (from the upper portion of the pit) was processed by heap leaching
Heap leaching
Heap leaching is an industrial mining process to extract precious metals, copper, uranium, and other compounds from ore.The process has ancient origins; one of the classical methods for the manufacture of copperas was to heap up iron pyrite and collect the leachate from the heap, which was then...
, either directly with sulfuric acid
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...
in vats to produce a copper solution precipitated by passing it over scrap iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
, or by leaching successively in acid and kerosene
Kerosene
Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...
solutions, subsequently electroplating onto stainless steel
Stainless steel
In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....
sheets. Copper sulfide
Sulfide
A sulfide is an anion of sulfur in its lowest oxidation state of 2-. Sulfide is also a slightly archaic term for thioethers, a common type of organosulfur compound that are well known for their bad odors.- Properties :...
ore from the lower portion of the pit was processed by crushing, and flotation
Froth flotation
Froth flotation is a process for selectively separating hydrophobic materials from hydrophilic. This is used in several processing industries...
with calcium oxide
Calcium oxide
Calcium oxide , commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline crystalline solid at room temperature....
added to the solution to maintain an alkali
Alkali
In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal element. Some authors also define an alkali as a base that dissolves in water. A solution of a soluble base has a pH greater than 7. The adjective alkaline is commonly used in English as a synonym for base,...
ne pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
.
Environmental issues
The mining wastes at the closed mining site have been investigated by the US Environmental Protection AgencyUnited States Environmental Protection Agency
The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...
. Since 2000, it has spent approximately $6 million addressing this issue and ARCO
ARCO
Atlantic Richfield Company is an oil company with operations in the United States as well as in Indonesia, the North Sea, and the South China Sea. It has more than 1,300 gas stations in the western part of the United States. ARCO was originally formed by the merger of East Coast-based Atlantic...
has spent $2.7 million to clean the site. In 2009 ARCO committed to spending $10.2 million for future and past cleanup work. Of the $10.2 million, $8 million is for future work and $2.2 million is to reimburse the EPA for past work completed. In 2008 ARCO reimbursed the EPA $2.7 million.