Hillsboro is an

unincorporated community An unincorporated area is a region that is not governed by a local municipal corporation. Widespread unincorporated communities and areas are a distinguishing feature of the United States and Canada. Most other countries of the world either have ...

in Sierra County,

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ker ...

, United States, located in the southwestern part of the state. It was founded in 1877, following the discovery of

gold Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile met ...

. The community was the county seat of Sierra County from 1884 until 1936, when Hot Springs (now called

Truth or Consequences ''Truth or Consequences'' is an American game show originally hosted on NBC radio by Ralph Edwards (1940–1957) and later on television by Edwards (1950–1954), Jack Bailey (1954–1956), Bob Barker (1956–1975), Steve Dunne (1957–1958), ...

) became the county seat. The town was named Hillsborough by prospectors in December 1877, but later shortened to Hillsboro. By 1880, the town had four companies of soldiers and 400 miners, but the population soon grew to 700. A county courthouse was built in 1892. By 1907, the population was 1200. A flood on 10 June 1914 caused considerable damage to many town buildings.

Geology

The first house was built in August 1877 after two

prospectors Prospecting is the first stage of the geological analysis (followed by Mining engineering#Pre-mining, exploration) of a territory. It is the search for minerals, fossils, precious metals, or mineral specimens. It is also known as fossicking. ...

, Dan Dugan and Dave Stitzel, working in the area of the future Opportunity Mine, collected loose pieces of rock (float is the geologic term) assayed at $160 per ton in gold and

silver Silver is a chemical element with the Symbol (chemistry), symbol Ag (from the Latin ', derived from the Proto-Indo-European wikt:Reconstruction:Proto-Indo-European/h₂erǵ-, ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, whi ...

. Soon,

ore Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 April 2 ...

was discovered at the nearby Rattlesnake

vein (geology) In geology, a vein is a distinct sheetlike body of crystallized minerals within a rock. Veins form when mineral constituents carried by an aqueous solution within the rock mass are deposited through precipitation. The hydraulic flow involved i ...

by Dugan and Frank Pitcher, and a

placer deposit In geology, a placer deposit or placer is an accumulation of valuable minerals formed by gravity separation from a specific source rock during sedimentary processes. The name is from the Spanish word ''placer'', meaning "alluvial sand". Placer min ...

of gold was found in November at the Rattlesnake and Wicks

gulch In xeric lands, a gulch is a deep V-shaped valley formed by erosion. It may contain a small stream or dry creek bed and is usually larger in size than a gully. Sudden intense rainfall upstream may produce flash floods in the bed of the gulch. I ...

es. Ore was pulverized with arrastres located in Hillsboro, including a 10-

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 operatio ...

built in 1878. Total production prior to 1904 was about $6,750,000. Between 1911 and 1931, total production of gold ore was 836 tons, gold-copper-silver ore was 5,470 tons, and

copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...

ore was 200 tons. In his report, Harley wrote, "The ore deposits of the Hillsboro or Las Animas mining district are of four general types as follows: (1)

fissure A fissure is a long, narrow crack opening along the surface of Earth. The term is derived from the Latin word , which means 'cleft' or 'crack'. Fissures emerge in Earth's crust, on ice sheets and glaciers, and on volcanoes. Ground fissure A ...

veins in

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomi ...

flows, (2) disseminated deposits in

monzonite Monzonite is an igneous intrusive rock, formed by slow cooling of underground magma that has a moderate silica content and is enriched in alkali metal oxides. Monzonite is composed mostly of plagioclase and alkali feldspar. Syenodiorite is an o ...

porphyry, (3) replacement deposits in

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

, and (4) placer gold deposits." The Copper Flat

volcano A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are ...

to the northeast of Hillsboro is the source of the gold in the area. The 4 mile wide volcano is characterized by a

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

quartz monzonite Quartz monzonite is an intrusive, felsic, igneous rock that has an approximately equal proportion of orthoclase and plagioclase feldspars. It is typically a light colored phaneritic (coarse-grained) to porphyritic granitic rock. The plagioclase ...

stock In finance, stock (also capital stock) consists of all the shares by which ownership of a corporation or company is divided.Longman Business English Dictionary: "stock - ''especially AmE'' one of the shares into which ownership of a company ...

within a topographic depression, surrounded by surface

flows at least 2,300 feet thick, and radial

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical form ...

latite Latite is an igneous, volcanic rock, with aphanitic- aphyric to aphyric-porphyritic texture. Its mineral assemblage is usually alkali feldspar and plagioclase in approximately equal amounts. Quartz is less than five percent and is absent in a f ...

rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral ...

dikes Dyke (UK) or dike (US) may refer to: General uses * Dyke (slang), a slang word meaning "lesbian" * Dike (geology), a subvertical sheet-like intrusion of magma or sediment * Dike (mythology), ''Dikē'', the Greek goddess of moral justice * Dikes, ...

. The stock generated the

porphyry copper deposit Porphyry copper deposits are copper ore bodies that are formed from hydrothermal fluids that originate from a voluminous magma chamber several kilometers below the deposit itself. Predating or associated with those fluids are vertical dikes of ...

s, gold-bearing veins, and gold placers. There are about 26 major veins forming a radial pattern from the stock. The Golddust Camp placer deposits are found in the

alluvium Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluv ...

of the dry

es radiating off Copper Flat and the andesite flows. The fissure veins produced 51,000 ounces of gold, while the placer deposits produced 110,000 ounces. The Sternberg Mine at Copper Flat produced 200 tons of copper ore between 1911 and 1934. By 1959, Bear Creek Mining Company had discovered a mineralized

breccia Breccia () is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix. The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of di ...

pipe Pipe(s), PIPE(S) or piping may refer to: Objects * Pipe (fluid conveyance), a hollow cylinder following certain dimension rules ** Piping, the use of pipes in industry * Smoking pipe ** Tobacco pipe * Half-pipe and quarter pipe, semi-circula ...

within the stock. Quintana Minerals Corporation started

open-pit mining Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining, is a surface mining technique of extracting rock or minerals from the earth from an open-air pit, sometimes known as a borrow. This form of mining ...

in 1980, averaging 0.45 per cent copper. Ore minerals include

pyrite The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Iron, FeSulfur, S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic Luster (mineralogy), lust ...

chalcopyrite Chalcopyrite ( ) is a copper iron sulfide mineral and the most abundant copper ore mineral. It has the chemical formula CuFeS2 and crystallizes in the tetragonal system. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mo ...

sphalerite Sphalerite (sometimes spelled sphaelerite) is a sulfide mineral with the chemical formula . It is the most important ore of zinc. Sphalerite is found in a variety of deposit types, but it is primarily in Sedimentary exhalative deposits, sedimen ...

and

galena Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver. Galena is one of the most abundant and widely distributed sulfide minerals. It cryst ...

Education

Truth or Consequences Municipal Schools Truth or Consequences Municipal Schools is a school district headquartered in Truth or Consequences, New Mexico Truth or Consequences (often abbreviated as T or C) is a city in New Mexico, and the county seat of Sierra County. In 2020, the ...

is the school district for the entire county. Truth or Consequences Middle School and Hot Springs High School, both in Truth or Consequences, are the district's secondary schools.

Notable people

* Physician and

American Civil War The American Civil War (April 12, 1861 – May 26, 1865; also known by other names) was a civil war in the United States. It was fought between the Union ("the North") and the Confederacy ("the South"), the latter formed by states th ...

veteran

C.C. Crews Charles Constantine Crews (September 3, 1829 – November 14, 1887) was an attorney, physician, railroad executive and Confederate Colonel in the American Civil War. Between 1862 and 1865, he participated in most of the Western Theater ca ...

* Future justice of the

New Mexico Supreme Court The New Mexico Supreme Court is the highest court in the U.S. state of New Mexico. It is established and its powers defined by Article VI of the New Mexico Constitution. It is primarily an appellate court which reviews civil and criminal decisi ...

Frank W. Parker. He presided over the 1899 murder trial of Albert J. Fountain.

Popular culture

* Mentioned in

Eugene Manlove Rhodes Eugene Manlove Rhodes (January 19, 1869 – June 27, 1934) was an American writer, nicknamed the "cowboy chronicler". He lived in south central New Mexico when the first cattle ranching and cowboys arrived in the area; when he moved to New York wi ...

' 1920 nove
Stepsons of Light
* About 1986, the film '' Lewis & Clark & George'' was filmed in the vicinity.

Notes

References

* Harley, George Townsend, ''The Geology and Ore Deposits of Sierra County, New Mexico'', New Mexico State Bureau of Mines and Mineral Resources Bulletin 10, 1934.

External links

Hillsboro, NM Town WebsiteHillsboro on the Sierra County Tourism websiteHillsboro features and attractions
City map showing locations of many historic buildings {{authority control Unincorporated communities in New Mexico Unincorporated communities in Sierra County, New Mexico Census-designated places in New Mexico Census-designated places in Sierra County, New Mexico