Silver King Mine
Encyclopedia
The Silver King Mine is an inactive silver mine located near Superior, Arizona in the United States. The richest silver mine in Arizona, it produced an estimated US$42 million worth of silver ore between 1875 and 1900.
The mine is located on four patented claims in Comstock Wash, about 1 mile west of Kings Crown Peak and about 3 miles north of Superior, in sec. 24, T1S, R12E.
. General George Stoneman
, desiring an easier access route to Apache strongholds, had ordered the construction of a road from Camp Picketpost
into the Pinal Mountains. The road became known as the Stoneman Grade. A soldier named Sullivan, who was assigned to the construction, discovered some heavy black rocks that flattened when struck. Interested in the rock, he collected several samples but did not mention this to his fellow soldiers. After completing his term of service, Sullivan went to work on a ranch owned by Charles Mason. Sullivan routinely showed off the rocks, known as "nugget silver" to prospectors of the region, but never divulged the location of the discovery. After a time, Sullivan disappeared and was assumed to have been killed by Apache.
Mason, joining with Benjamin W. Regan, William H. Long, Isaac Copeland, and another companion went searching for the location of Sullivan's find. On March 21, 1875 the group was attacked by Apache and the unnamed companion was killed and buried near the summit of Stoneman Grade. Following the burial, one of the group's mules strayed. Copeland was sent to find the wayward animal, locating it near the base of Stoneman Grade. Upon finding the mule, Copeland noticed an unusual rock outcropping and upon closer inspection saw markings that had been left by Sullivan. Sullivan's find had been located.
porphyry
and Pinal Schist
. The orebody formerly cropped out at the top of a little hill about 75 feet high, composed of heavily-altered yellowish-brown to greenish-gray porphyry. Stromeyerite
and highly argentiferous tetrahedrite
with some acanthite
were the most important ore minerals in the upper levels, and argentiferous sphalerite
had become the principal ore mineral in the lower levels of the mine.
report, the four surviving partners divided ownership of the find equally. Initially the mine's ore was shipped directly to San Francisco for processing. Shortly thereafter, a smelting
operation was set up several miles from the mine along the Arnett Creek. A mining camp, which grew into Pinal City
, quickly formed at the processing site.
Initially operating the mine together, Copeland sold his interest to Mason in June 1876 with Long selling his interest several months later to Regan. Mason and Regan, who had spent US$80,000 to buy out their partner's interests, later sold their interests to James M. Barney for US$250,000 and US$300,000 respectively.
The operations continued until 1888, when a combination of deteriorating ore quality and lower silver prices prompted the mine to close. Sporadic, small-scale mining continued into the 1980s. Recorded production 5,943,157 oz. Ag, valued at $6,526,094 (1875-1889), and 232,764 oz. Ag valued at $252,674 (1918-1928) (period values).
The mine is located on four patented claims in Comstock Wash, about 1 mile west of Kings Crown Peak and about 3 miles north of Superior, in sec. 24, T1S, R12E.
Discovery
The Silver King Mine traces its beginning to 1870, during the Apache WarsApache Wars
The Apache Wars were a series of armed conflicts between the United States and Apaches fought in the Southwest from 1849 to 1886, though other minor hostilities continued until as late as 1924. The Confederate Army participated in the wars during the early 1860s, for instance in Texas, before being...
. General George Stoneman
George Stoneman
George Stoneman, Jr. was a career United States Army officer, a Union cavalry general in the American Civil War, and the 15th Governor of California between 1883 and 1887.-Early life:...
, desiring an easier access route to Apache strongholds, had ordered the construction of a road from Camp Picketpost
Picketpost Mountain
Picketpost Mountain is located just outside the town of Superior, Arizona approximately east of the Phoenix Metro Area. The mountain is located in the southern desert region of Tonto National Forest and is popular with hikers...
into the Pinal Mountains. The road became known as the Stoneman Grade. A soldier named Sullivan, who was assigned to the construction, discovered some heavy black rocks that flattened when struck. Interested in the rock, he collected several samples but did not mention this to his fellow soldiers. After completing his term of service, Sullivan went to work on a ranch owned by Charles Mason. Sullivan routinely showed off the rocks, known as "nugget silver" to prospectors of the region, but never divulged the location of the discovery. After a time, Sullivan disappeared and was assumed to have been killed by Apache.
Mason, joining with Benjamin W. Regan, William H. Long, Isaac Copeland, and another companion went searching for the location of Sullivan's find. On March 21, 1875 the group was attacked by Apache and the unnamed companion was killed and buried near the summit of Stoneman Grade. Following the burial, one of the group's mules strayed. Copeland was sent to find the wayward animal, locating it near the base of Stoneman Grade. Upon finding the mule, Copeland noticed an unusual rock outcropping and upon closer inspection saw markings that had been left by Sullivan. Sullivan's find had been located.
Geology and mineralization
Mineralization is hosted in Pinal Schist and in Silver King Quartz Diorite. Veinlets are interlaced in quartz dioriteQuartz diorite
Quartz diorite is an igneous, plutonic rock, of felsic composition, with phaneritic texture. Feldspar is present as plagioclase with 10% or less potassium feldspar. Quartz is present at between 5 to 20% of the rock. Biotite, amphiboles and pyroxenes are common dark accessory...
porphyry
Porphyritic
Porphyritic is an adjective used in geology, specifically for igneous rocks, for a rock that has a distinct difference in the size of the crystals, with at least one group of crystals obviously larger than another group...
and Pinal Schist
Schist
The schists constitute a group of medium-grade metamorphic rocks, chiefly notable for the preponderance of lamellar minerals such as micas, chlorite, talc, hornblende, graphite, and others. Quartz often occurs in drawn-out grains to such an extent that a particular form called quartz schist is...
. The orebody formerly cropped out at the top of a little hill about 75 feet high, composed of heavily-altered yellowish-brown to greenish-gray porphyry. Stromeyerite
Stromeyerite
Stromeyerite is a sulfide mineral of copper and silver, with the chemical formula AgCuS. It forms opaque blue grey to dark blue orthorhombic crystals....
and highly argentiferous tetrahedrite
Tetrahedrite
Tetrahedrite is a copper antimony sulfosalt mineral with formula: 12Sb4S13. It is the antimony endmember of the continuous solid solution series with arsenic bearing tennantite. Pure endmembers of the series are seldom if ever seen in nature. Of the two, the antimony rich phase is more common...
with some acanthite
Acanthite
Acanthite, Ag2S, crystallizes in the monoclinic system and is the stable form of silver sulfide below 173 °C. Argentite is the stable form above that temperature. As argentite cools below that temperature its cubic form is distorted to the monoclinic form of acanthite. Below 173 °C...
were the most important ore minerals in the upper levels, and argentiferous sphalerite
Sphalerite
Sphalerite is a mineral that is the chief ore of zinc. It consists largely of zinc sulfide in crystalline form but almost always contains variable iron. When iron content is high it is an opaque black variety, marmatite. It is usually found in association with galena, pyrite, and other sulfides...
had become the principal ore mineral in the lower levels of the mine.
Operation
Following a highly favorable assayerAssayer
An assayer is a person who tests ores and minerals and analyzes them to determine their composition and value. They may use spectrographic analysis, chemical solutions, and chemical or laboratory equipment, such as furnaces, beakers, graduates, pipettes, and crucibles.An assayer separates metals...
report, the four surviving partners divided ownership of the find equally. Initially the mine's ore was shipped directly to San Francisco for processing. Shortly thereafter, a smelting
Smelting
Smelting is a form of extractive metallurgy; its main use is to produce a metal from its ore. This includes iron extraction from iron ore, and copper extraction and other base metals from their ores...
operation was set up several miles from the mine along the Arnett Creek. A mining camp, which grew into Pinal City
Pinal City, Arizona
Pinal or Pinal City is a ghost town in Pinal County in the U.S. state of Arizona. The town was populated from the 1870s into the 1890s, in what was then the Arizona Territory....
, quickly formed at the processing site.
Initially operating the mine together, Copeland sold his interest to Mason in June 1876 with Long selling his interest several months later to Regan. Mason and Regan, who had spent US$80,000 to buy out their partner's interests, later sold their interests to James M. Barney for US$250,000 and US$300,000 respectively.
The operations continued until 1888, when a combination of deteriorating ore quality and lower silver prices prompted the mine to close. Sporadic, small-scale mining continued into the 1980s. Recorded production 5,943,157 oz. Ag, valued at $6,526,094 (1875-1889), and 232,764 oz. Ag valued at $252,674 (1918-1928) (period values).