Auriferous greenschist, Homestake Mine SD

The Homestake Mine was a deep underground

gold mine Gold Mine may refer to: * Gold Mine (board game) *Gold Mine (Long Beach), an arena *"Gold Mine", a song by Joyner Lucas from the 2020 album ''ADHD Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characteri ...

(8,000 feet or 2,438 m) located in Lead, South Dakota. Until it closed in 2002 it was the largest and deepest gold mine in

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

. The mine produced more than of gold during its lifetime. This is about or a volume of gold roughly equal to 18,677 US gallons. The Homestake Mine is famous in scientific circles because of the work of a deep underground laboratory that was established there in the mid-1960s. This was the site where the

solar neutrino problem The solar neutrino problem concerned a large discrepancy between the flux of solar neutrinos as predicted from the Sun's luminosity and as measured directly. The discrepancy was first observed in the mid-1960s and was resolved around 2002. The fl ...

was first discovered, in what is known as the Homestake Experiment.

Raymond Davis Jr. Raymond Davis Jr. (October 14, 1914 – May 31, 2006) was an American chemist and physicist. He is best known as the leader of the Homestake experiment in the 1960s-1980s, which was the first experiment to detect neutrinos emitted from the Sun; f ...

conducted this experiment in the mid-1960s, which was the first to observe solar neutrinos. On July 10, 2007, the mine was selected by the

National Science Foundation The National Science Foundation (NSF) is an independent agency of the United States government that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National ...

as the location for the

Deep Underground Science and Engineering Laboratory The Sanford Underground Research Facility (SURF), or Sanford Lab, is an underground laboratory in Lead, South Dakota. The deepest underground laboratory in the United States, it houses multiple experiments in areas such as dark matter and neutrin ...

(DUSEL). It won over several candidates, including the

Henderson Mine The Henderson molybdenum mine is a large underground molybdenum mine west of the town of Empire in Clear Creek County, Colorado, USA. The Henderson mine, which has produced molybdenum since 1976, is owned by Freeport-McMoRan. The Henderson m ...

near Empire, Colorado.

History

The Homestake deposit was discovered by Fred and Moses Manuel, Alex Engh, and Hank Harney in April 1876, during the

Black Hills Gold Rush The Black Hills Gold Rush took place in Dakota Territory in the United States. It began in 1874 following the Custer Expedition and reached a peak in 1876–77. Rumors and poorly documented reports of gold in the Black Hills go back to the early ...

, when gold was discovered in the Black Hills, an area that had been guaranteed to the Lakota Nation by the Fort Laramie Treaty. A trio of mining entrepreneurs, George Hearst, Lloyd Tevis, and

James Ben Ali Haggin James Ben Ali Haggin (December 9, 1822 – September 12, 1914) was an American attorney, rancher, investor, art collector, and a major owner and breeder in the sport of Thoroughbred horse racing. Haggin made a fortune in the aftermath of the C ...

, bought the claim from them for $70,000 in 1877. George Hearst reached Deadwood in October 1877, and took control of the mine property. Hearst arranged to haul the mining equipment by wagon from the nearest railhead in

Sidney, Nebraska Sidney is a city in and the county seat of Cheyenne County, Nebraska, United States. The city is north of the Colorado state line. The population was 6,757 at the 2010 census. History The city was named for Sidney Dillon, president of the ...

Arthur De Wint Foote Arthur De Wint Foote (1849–1933) was an American civil engineer and mining engineer who impacted the development of the American West with his innovative engineering works and entrepreneurial ventures. In Northern California in the late 189 ...

worked as an engineer. Despite the remote location, deep mines were dug and ore began to be produced. An 80-

stamp mill A stamp mill (or stamp battery or stamping mill) is a type of mill machine that crushes material by pounding rather than grinding, either for further processing or for extraction of metallic ores. Breaking material down is a type of unit operati ...

was built, and began crushing Homestake ore by July 1878. In 1879 the partners sold shares in the

Homestake Mining Company Homestake Mining Company was one of the largest gold mining businesses in the United States and the owner of the Homestake Mine in Lead, South Dakota. Founded in 1877, it was acquired by Barrick Gold in December 2001. Homestake was the longest-l ...

, and listed it on the

New York Stock Exchange The New York Stock Exchange (NYSE, nicknamed "The Big Board") is an American stock exchange in the Financial District of Lower Manhattan in New York City. It is by far the world's largest stock exchange by market capitalization of its liste ...

. The Homestake would become one of the longest-listed stocks in the history of the NYSE, as Homestake operated the mine until 2001. Hearst consolidated and enlarged the Homestake property by fair and foul means. He bought out some adjacent claims, and secured others in the courts. A Hearst employee killed a man who refused to sell his claim, but was acquitted in court after all the witnesses disappeared. Hearst purchased newspapers in Deadwood to influence public opinion. An opposing newspaper editor was physically attacked on a Deadwood street. Hearst realized that he might be on the receiving end of violence, and wrote a letter to his partners asking them to provide for his family should he be murdered. Within three years, Hearst had established the mine and acquired significant claims. He walked out alive, and very rich. By the time Hearst left the Black Hills in March 1879, he had added the claims of Giant, Golden Star, Netty, May Booth, Golden Star No. 2, Crown Point, Sunrise, and General Ellison to the original two claims of the Manuel Brothers, Golden Terra and Old Abe, totaling . The ten-stamp mill had become 200, and 500 employees worked in the mine, mills, offices and shops. Hearst owned the Boulder Ditch and water rights to Whitewood Creek, monopolizing the region. His railroad,

Black Hills & Fort Pierre Railroad The Black Hills and Fort Pierre Railroad (BH&FP) was a narrow gauge By 1900, Homestake owned 300 claims, on , and was worked by more than 2000 employees.Bronson, W., and Watkins, T.H., ''Homestake,'' San Francisco: Homestake Mining Company, 1977 In 1901, the mine started using compressed air locomotives, fully replacing mules and horses by the 1920s. Charles Washington Merrill introduced cyanidization to augment mercury-amalgamation for gold recovery. "Cyanide Charlie" achieved 94 per cent recovery. The gold was shipped to the

Denver Mint The Denver Mint is a branch of the United States Mint that struck its first coins on February 1, 1906. The mint is still operating and producing coins for circulation, as well as mint sets and commemorative coins. Coins produced at the Denver Min ...

. By 1906, the Ellison Shaft reached , the B&M , the Golden Star , and the Golden Prospect , producing of ore. A disastrous fire struck on 25 March 1907, which took forty days to extinguish after the mine was flooded. Another disastrous fire struck in 1919. In 1927, company geologist Donald H. McLaughlin used a

winze A winze is a minor connection between different levels in a mine. When worked upwards from a lower level it is usually called a raise; when sunk downward from a higher level it may be called a sump. The top of a winze is located underground and i ...

from the 2,000 level to demonstrate that ore reached the 3,500 foot level. The Ross shaft was started in 1934, a second winze from the level reached , and a third winze from was started in 1937. The Yates shaft was started in 1938. Production ceased during WWII from 1943 until 1945, due to Limitation Order L-208 from the

War Production Board The War Production Board (WPB) was an agency of the United States government that supervised war production during World War II. President Franklin D. Roosevelt established it in January 1942, with Executive Order 9024. The WPB replaced the Su ...

. By 1975, mining operations had reached the level, and two winzes were planned to . Homestake Mine gold ore, town of Lead, northern Black Hills, western South Dakota (3

Homestake Mine gold ore, town of Lead, northern Black Hills, western South Dakota (3

The gold ore mined at Homestake was considered low grade (less than one ounce per ton), but the body of ore was large. Through 2001, the mine produced of gold and of silver. In terms of total production, the Lead mining district, of which the Homestake mine is the only producer, was the second-largest gold producer in the United States, after the Carlin district in

Nevada Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...

. Homestake was the longest continually operating mine in United States history. The Homestake mine ceased production at the end of 2001. Reasons included low gold prices, poor ore quality, and high costs.

Conversion to use for scientific research

The

Barrick Gold Barrick Gold Corporation is a mining company that produces gold and copper with 16 operating sites in 13 countries. It is headquartered in Toronto, Ontario, Canada. It has mining operations in Argentina, Canada, Chile, Côte d'Ivoire, Democra ...

corporation (which had merged with the Homestake Mining Company in mid-2001) agreed in early 2002 to keep

dewatering Dewatering is the removal of water from a location. This may be done by wet classification, centrifugation, filtration, or similar solid-liquid separation processes, such as removal of residual liquid from a filter cake by a filter press as p ...

the mine while owners were negotiating with the

over the mine as a potential site for a new deep underground laboratory (DUSEL). But progress was slow and maintaining the pumps and ventilation was costing $250,000 per month. The owners switched the equipment off on June 10, 2003 and closed the mine completely. The Homestake Mine was selected in 2007 by NSF for the

(DUSEL). In June 2009, researchers at University of California Berkeley announced that Homestake would be reopened for scientific research on neutrinos and dark matter particles using DUSEL and

Large Underground Xenon experiment The Large Underground Xenon experiment (LUX) aimed to directly detect weakly interacting massive particle (WIMP) dark matter interactions with ordinary matter on Earth. Despite the wealth of (gravitational) evidence supporting the existence of non-b ...

. Research into

enhanced geothermal system An enhanced geothermal system (EGS) generates geothermal electricity without the need for natural convective hydrothermal resources. Until recently, geothermal power systems have exploited only resources where naturally occurring heat, water, a ...

s is being prepared in the mine.

Geology

The gold at Homestake is almost exclusively confined to the Homestake Formation, an Early

Proterozoic The Proterozoic () is a geological eon spanning the time interval from 2500 to 538.8million years ago. It is the most recent part of the Precambrian "supereon". It is also the longest eon of the Earth's geologic time scale, and it is subdivided i ...

layer with

iron carbonate Iron(II) carbonate, or ferrous carbonate, is a chemical compound with formula , that occurs naturally as the mineral siderite. At ordinary ambient temperatures, it is a green-brown ionic solid consisting of iron(II) cations and carbonate anions ...

and iron silicate. The original 20–30 m thick Homestake Formation, has been deformed and metamorphosed, resulting in upper greenschist facies of

siderite Siderite is a mineral composed of iron(II) carbonate (FeCO3). It takes its name from the Greek word σίδηρος ''sideros,'' "iron". It is a valuable iron mineral, since it is 48% iron and contains no sulfur or phosphorus. Zinc, magnesium and ...

- phyllite, and lower

amphibolite Amphibolite () is a metamorphic rock that contains amphibole, especially hornblende and actinolite, as well as plagioclase feldspar, but with little or no quartz. It is typically dark-colored and dense, with a weakly foliated or schistose (flak ...

facies of grunerite schists. The iron may have been deposited by volcanic exhalation, perhaps in the presence of

microorganism A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in old ...

s as a

banded iron formation Banded iron formations (also known as banded ironstone formations or BIFs) are distinctive units of sedimentary rock consisting of alternating layers of iron oxides and iron-poor chert. They can be up to several hundred meters in thickness ...

. Gold ore mineralization is most intense in the Main Ledge, at the surface, and the 9 Ledge, at the 3200 level (feet below the Incline Shaft, at 1594 m above sea level). File:Homestake.jpg, Gold production and ore ledge discoveryCaddey, S.W., Bachman, R.L., Campbell, T.J., Reid, R.R., and Otto, R.P., 1991, The Homestake Gold Mine, An Early Protozoroic Iron-Formation-Hosted Gold Deposit, Lawrence County, South Dakota, in Geology and Resources of Gold in the United States, USGS Bulletin 1857, Washington: United States Government Printing Office File:Homestake2.jpg, Geologic map of the Black Hills File:Homestake3.jpg, Geologic cross section. The Homestake Formation has been deformed into

syncline In structural geology, a syncline is a fold with younger layers closer to the center of the structure, whereas an anticline is the inverse of a syncline. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimpose ...

s, odd numbers, and

anticline In structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex up in which the hinge or crest is t ...

s, even numbers. Ore

mineralization Mineralization may refer to: * Mineralization (biology), when an inorganic substance precipitates in an organic matrix ** Biomineralization, a form of mineralization ** Mineralization of bone, an example of mineralization ** Mineralized tissues ar ...

occurred mainly in the synclines, called Ledges. File:Lead Geologic Map.jpg, Lead Geologic Map. Note the locations of the Ellison, Old Abe, Highland, Deadwood Terra, and DeSmet shafts, south to north. The Caledonia Cut is labelled with a "1".Paige, S., 1924, Geology of the Region Around Lead South Dakota, USGS Bulletin 765, Washington:Government Printing Office File:Lead Geologic Map Legend.jpg, Lead Geologic Map Legend

References

External links

Homestake mine visitors center websiteSanford Underground Laboratory at HomestakeHomestake DUSELBlack Hills Geology photo album
mostly of the mine area, by geologist James St. John {{Black Hills, South Dakota Black Hills Gold mines in the United States Buildings and structures in Lawrence County, South Dakota Surface mines in the United States Underground mines in the United States Former mines in the United States Mines in South Dakota Tourist attractions in Lawrence County, South Dakota Stamp mills 2002 disestablishments in South Dakota

History

Conversion to use for scientific research

Geology

See also

References

Further reading

External links