Gold Cliff Mine

Site Name

Primary: Gold Cliff Mine
Secondary: Utica-Stickles Mine

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Commodity

Primary: Gold
Secondary: Silver

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Location

State: California
County: Calaveras
District: Angels Camp

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Land Status

Land ownership: Private
Note: the land ownership field only identifies whether the area the mine is in is generally on public lands like Forest Service or BLM land, or if it is in an area that is generally private property. It does not definitively identify property status, nor does it indicate claim status or whether an area is open to prospecting. Always respect private property.
Administrative Organization: City of Angels Camp

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Holdings

Not available

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Workings

Not available

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Ownership

Not available

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Production

Not available

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Deposit

Record Type: Site
Operation Category: Past Producer
Deposit Type: Hydrothermal vein
Operation Type: Surface-Underground
Discovery Year: 1850
Years of Production:
Organization:
Significant: Y
Deposit Size: S

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Physiography

Not available

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Mineral Deposit Model

Model Name: Low-sulfide Au-quartz vein

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Orebody

Form: Tabular, pinch and swell

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Structure

Type: L
Description: Melones Fault Zone

Type: R
Description: Bear Mountains fault zone, Melones fault zone

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Alterations

Alteration Type: L
Alteration Text: Ankeritic and sericitic alteration of wall rock with disseminated aurtiferous pyrite mineralization

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Rocks

Name: Schist
Role: Host
Description: chloritic and talcose
Age Type: Host Rock
Age Young: Mesozoic
Age Old: Paleozoic

Name: Amphibole Schist
Role: Host
Age Type: Host Rock
Age Young: Mesozoic
Age Old: Paleozoic

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Analytical Data

Not available

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Materials

Ore: Gold
Ore: Pyrite
Gangue: Quartz
Gangue: Calcite
Gangue: Talc
Gangue: Chalcopyrite
Gangue: Ankerite
Gangue: Sericite

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Comments

Comment (Development): The Gold Cliff Mine was discovered in 1850, but was not mined extensively until after it was taken over by the Utica Gold Mining Company in 1884. A shaft was sunk from the bottom of the open cut and the mine was operated from 1889 until April, 1920, three years longer than the company's larger property, the neighboring Utica Mine. The Gold Cliff mine property was comprised of the Gold Gliff , Pilot Knob, Madison, Specimen, Fairfax, Excelsior. Peachey, and No. 1 and No. 2 placer claims. Adverse economic conditions and falling off in the working efficiency of miners are said to have hastened closing. The Utica Mining Company reported that the total mine production was $2,834,000 (Logan, 1934). Except for sampling of the open cut in the 1930s, the mine has been idle since 1920.

Comment (Economic Factors): Clark (1970) reported that that Gold Cliff Mine produced $2,834,000+ in gold. The average value of the ore mined averaged $2.00 to $2.50 per ton with sulfide concentrates ranging from $30 to $50 per ton (Clark and Lydon, 1962).

Comment (Identification): The Gold Cliff Mine is located within the city of Angels Camp in southwestern Calaveras County, California. The gold mines in and around Angels Camp are part of the Angels Camp mining district, which produced at least $30 million in gold. The Gold Cliff Mine is credited with a production of $2,834,000 (Clark, 1970). The Gold Cliff Mine was discovered in 1850 and went on to become one of the better known gold mines in the county. The mine was ultimately taken over by the Utica Gold Mining Company in 1884 and operated until 1920 in conjunction with the company's larger property, the neighboring Utica Mine.

Comment (Location): Location selected for latitude and longitude is the Gold Cliff Mine shaft symbol on the USGS 7.5 minute Angels Camp quadrangle

Comment (Commodity): Commodity Info: Average ore values ranged from $2.00 to $2.50per ton. Sulfide concentrates ranged $30 to $50 per ton

Comment (Commodity): Ore Materials: Quartz-calcite stringer veins containing free gold and auriferous pyrite, and mineralized schist wallrock

Comment (Geology): REGIONAL GEOLOGY The Angels Camp district is within the Sierra foothills, where bedrock consists of north trending tectonostratigraphic belts of metamorphosed sedimentary, volcanic, and intrusive rocks that range in age from late Paleozoic to Mesozoic. The structural belts, which extend about 235 miles along the western side of the Sierra, are flanked to the east by the Sierra Nevada Batholith and to the west by sedimentary rocks of the Cretaceous and Jurassic Great Valley sequence. The structural belts are internally bounded by the Melones and Bear Mountains fault zones and are characterized by extensive faulting, shearing, and folding (Earhart, 1988). From El Dorado County southward into Tuolumne County, lode gold deposits occur in three distinct lithologic belts - the West Gold Belt, the Mother Lode Belt, and the East Gold Belt. The Mother Lode Belt is responsible for most of the gold produced. However, there has also been substantial gold production from the West Belt and East Belt. The West Belt consists of widely scattered gold deposits located west of the Mother Lode vein system. Gold occurs in irregular quartz veins and stringers in schist, slate, granitic rocks, altered mafic rocks, and as gray ore in greenstone. The West Belt can be divided into an eastern component composed of an ophiolitic melange and a western component composed of Jurassic rocks of the Copper Hill volcanics, Salt Springs slate, and Gopher Ridge volcanics. The Bear Mountains fault zone separates the melange from the Copper Hill volcanics. The Mother Lode Belt traverses western Calaveras County and consists of the upper Jurassic Logtown Ridge and upper Jurassic Mariposa formations. The Logtown Ridge Formation consists of about 6,500 feet of volcanic and volcanic-sedimentary rocks of island arc affinity. These rocks are mostly basaltic and include flows, breccias, and a variety of layered pyroclastic rocks. The overlying Mariposa Formation contains a distal turbidite, hemipelagic sequence of black slate, schist, amphibolite and chlorite schist, fine-grained tuffaceous rocks, and subvolcanic intrusive rocks. The thickness of the Mariposa Formation is difficult to ascertain due to structural complexities, but is estimated to be about 2,600 feet thick at the Cosumnes River (Earhart, 1988). Mother Lode mineralization is characterized by steeply dipping gold-bearing quartz veins and bodies of mineralized country rock adjacent to veins. Mother Lode veins are characteristically enclosed in Mariposa Formation slate with associated greenstone. The Mother Lode belt vein system ranges from a few hundred feet to a mile or more in width. Within the zone are numerous discontinuous or linked veins, which may be parallel, convergent, or en echelon. The veins commonly pinch and swell. Few can be traced more than a few thousand feet. Mother Lode type veins fill voids created within faults and fracture zones and consist of quartz, gold and associated sulfides, ankerite, calcite, chlorite, limonite, talc, and sericite. Stringer veins are commonly found in both adjacent footwall and hanging walls. Mother Lode ores are generally low to moderate grade (1/3 ounce of gold or less per ton), but ore bodies can be large. Ore shoots are generally short, 200-300 feet being the average stope length. However, they persist at depth, some having been mined to several thousand feet (Clark and Lydon, 1962). Ore shoots are commonly localized at bulges in veins, shear zones, vein intersections, or near abrupt changes in strike or dip.

Comment (Deposit): The ore bodies in the Gold Cliff Mine are not within simple veins like many Mother Lode deposits, but instead consist of numerous lenticular stringer veins separated by various thicknesses of fissured and mineralized amphibolite and chloritic and talcose schist. The stringers range from a few inches to three feet thick and are largely quartz, but carbonate is abundant, especially in the smaller fissures. In the Gold Cliff mine, the stringers strike about N 50? W and dip northeasterly, lying nearly in the planes of schistosity of the country rock (Eisenhauer, 1932). Both the quartz and nearby country rock contain free gold and auriferous pyrite. The schist is greatly altered and pyritized and carries the greater gold values. The schists are largely altered and composed of ankerite and sericite, with subordinate quartz, albite, and pyrite.

Comment (Geology): Wall rocks have invariably been hydrothermally altered, having been partially to completely converted to ankerite, sericite, quartz, pyrite, arsenopyrite, chlorite, and albite with traces of rutile and leucoxene (Knopf, 1929). The mineralization is usually adjacent to the veins in ground that has been fractured and contains small stringers and lenses of quartz. Locally, greenstone bodies adjacent to the quartz veins contain enough disseminated auriferous pyrite in large enough bodies to constitute what has been called "gray ore". Altered slate wall rock commonly contains pyrite, arsenopyrite, quartz, chlorite, and sericite with or without ankerite (Zimmerman, 1983). Large bodies of mineralized schist also form low-grade ore bodies throughout the Mother Lode. This ore consists of amphibolite schist that has been subjected to the same processes of alteration, replacement, and deposition that formed the greenstone gray ores. The altered schist consists mainly of ankerite, sericite, chlorite, quartz, and albite. Gold is associated with the pyrite and other sulfides that are present. Pyrite comprises about 8 percent of the rock. The average grade of mineralized schist is about 0.1 oz per ton. The Melones Fault zone separates the Mother Lode Belt from the East Belt. The Eastern Belt is dominantly argillite, phyllite and phyllonite, chert, and metavolcanic rocks of Paleozoic-Mesozoic age. The phyllite and phyllonite are dark to silvery gray. The chert is mostly thin bedded with phyllite partings. The Paleozoic-Mesozoic metasedimentary and metavolcanic rocks of the Eastern Belt have been assigned to the Calaveras Complex by most investigators (Earhart, 1988). Older Paleozoic metamorphic rocks have been assigned to the Shoo Fly Complex. The metamorphic complexes have are intruded in places by Mesozoic plutonic rocks. Lode deposits of the East Belt consist of many individual gold-bearing quartz veins enclosed in metamorphic rocks of possible Jurassic age, metamorphic rocks of the Calaveras Complex, metamorphic rocks of the Shoo Fly complex, or in granitic rocks. Most of the veins trend northward and dip steeply. An east-west set of intersecting faults may be a controlling factor in controlling deposition of ore. Ore deposits of the East Belt are smaller and narrower than those of the Mother Lode, but commonly are more chemically complex, and richer in grade. Gold is usually associated with appreciable amounts of pyrite, chalcopyrite, pyrrhotite, galena, sphalerite, and arsenopyrite. LOCAL GEOLOGY The geology of the Angels Camp district is complex. Bedrock, which is assigned either to the Calaveras Complex or unnamed units of Jurassic age, consists of a series of northwest-striking beds of amphibolite and chlorite schists, phyllite, greenstone, and metagabbro. Ore deposits occur either in amphibolite and chlorite schist or phyllite. There are three principal northwest striking vein systems in the district. In the westernmost system, the veins are in phyllite. In the center system, which includes the Gold Cliff Mine, the veins are along the western margin of a northwest trending belt of metagabbro. In the eastern system, the ore deposits occur in amphibolite and greenstone. To the east and west of the district, bedrock is composed of slate, impure quartzite, and micaceous schist (Clark, 1970). The deposit in the Gold Cliff Mine is very similar to that worked in the larger Utica Mine located about one mile to the east. These mines exploited parallel ore bodies called the Gold Cliff vein and Utica vein respectively.

Comment (Geology): At the surface, the veins were 3000 feet apart. The Gold Cliff vein strikes northwestward and dips 45? NE in the upper workings, but the dip flattens to as little as 7 degrees on the 1700-foot level (Knopf, 1929) causing the veins to converge at about the 2700 foot level in the Utica Mine workings. Despite the common occurrence of high-grade ore bodies at vein intersections in many Mother Lode vein systems, no high-grade ore was encountered at the junction of these veins. The ore bodies in both mines are not within simple veins like many Mother Lode deposits, but instead consist of numerous lenticular stringer veins separated by various thicknesses of fissured and mineralized amphibolite and chloritic and talcose schist. The stringers range from a few inches to three feet thick and are largely quartz, but carbonate is abundant, especially in the smaller fissures. In the Gold Cliff mine, the stringers strike about N 50? W and dip northeasterly, lying nearly in the planes of schistosity of the country rock (Eisenhauer, 1932). Both the quartz and nearby country rock contain free gold and auriferous pyrite. The schist is greatly altered and pyritized and carries the greater gold values. The schists are largely altered and compose of ankerite and sericite, with subordinate quartz, albite, and pyrite. Rutile is a common accessory forming minute prisms. Pyrite is developed metasomatically in the schists as sharp cubes. In the Gold Cliff Mine, the cubes can attain large size- half an inch or more in dimensions (Knopf, 1929). The large coarse pyrite cubes carried only $5 per ton, and are thought to represent the primary pyrite of the original igneous rock from which the schist was derived. The fine disseminated pyrite crystals of which concentrates yielded concentrates worth $50 to $80 per ton, are thought to the result of hydrothermal alteration and enrichment (Logan, 1936). The quartz veinlets, unless they contain pyrite are poorly mineralized (Knopf, 1929). The average value of the ore mined averaged $2.00 to $2.50 per ton with sulfide concentrates ranging from $30 to $50 per ton (Clark and Lydon, 1962). In the upper workings, the Gold Cliff ore body was nearly 100 feet thick, but the footwall converges toward the hanging with depth and to the south. The immediate hanging wall of the ore body was a massive barren quartz vein 4 top 6 feet thick. At depth, the hanging wall was a hard, grooved amphibolite schist that stood without timbering and was a major factor in permitting low-cost mining operations (Logan, 1934). Between the 1600 and 1700-foot levels, a nearly horizontal reverse fault of several hundred feet of displacement offsets the ore body to the north. On the 1700-foot level the lode was also displaced by a steep eastward dipping post mineralization normal fault which had dropped the lode 3 feet on the east side of the fault. The displacement was reported to increase southward along the strike of the fault (Knopf, 1929). On the 1700-foot level the lode was also displaced by a steep eastward dipping post mineralization normal fault which had dropped the lode 3 feet on the east side of the fault. The displacement was reported to increase southward along the strike of the fault (Knopf, 1929).

Comment (Commodity): Gangue Materials: Quartz, calcite, talc, chalcopyrite, ankerite, and sericite

Comment (Workings): The upper part of the Gold Cliff workings were developed by an open cut. Deeper workings were accessed through a 3-compartment, 1700- foot inclined shaft. The shaft was inclined 45? to the 1600-foot level, below which it was inclined 12 degrees. Where the vein flattened on the 1700-foot level, a drift was run north 800 feet from the bottom of the 1700 foot shaft and a winze was sunk from near the face to a depth of 270 feet. A northeast crosscut on the 1400-foot level connected with the 1500-foot level of the neighboring Utica Mine. Few additional details of the underground workings are available, but a portion of the workings are shown Clark and Lydon (1962, fig. 10, p. 73). Open stopes with pillars were employed, and little timbering was required. Ore was hoisted from the inclined shaft and trammed to the mill by electric traction. Ore was crushed with a Blake crusher and treated in a 200-ton, 40-stamp mill (Clark and Lydon, 1962). Battery pulp was concentrated on twenty-four 4-foot Frue vanners. A 90% recovery was made by amalgamation and concentration. Concentrates were valued at $30 to $50 per ton (Tucker, 1915)

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References

Reference (Deposit): Clark, L.D., 1970, Geology of the San Andreas 15-minute quadrangle, Calaveras County, California: California Division of Mines and Geology Bulletin 195, 23 p.

Reference (Deposit): Brown, J. A., 1890, Calaveras County, Gold Cliff Mine: California State Mining Bureau, 10th Annual Report of the State Mineralogist, p. 150.

Reference (Deposit): Clark, W. B., 1970, Gold districts of California: California Divisions of Mines and Geology Bulletin 193, p. 25-28.

Reference (Deposit): Clark. W. B., and Lydon, P.A., 1962, Mines and mineral resources of Calaveras County, California: California Division of Mines and Geology County Report No. 2, p. 55.

Reference (Deposit): Earhart, R.L., 1988, Geologic setting of gold occurrences in the Big Canyon area, El Dorado County, California: U.S. Geological Survey Professional Paper 1576, 13 p.

Reference (Deposit): Eric, J.H., Stromquist, A.A., and Swinney, C.M., 1955, Geology and mineral deposits of the Angels Camp and Sonora quadrangles, Calaveras and Tuolumne counties, California: California Division of Mines Special Report 41, 55 p.

Reference (Deposit): Julihn, C.E., and Horton, F.W., Mineral industries survey of the United States - Mines of the southern Mother Lode Region, Part 1, Calaveras County, Utica and Gold Cliff mines: U.S. Bureau of Mines Bulletin 413, p. 136.

Reference (Deposit): Logan, C. A., 1934, Mother Lode Gold belt of California: California Division of Mines and Geology Bulletin 108, p. 140-141.

Reference (Deposit): Knopf, A., 1929, The Mother Lode system of California: U. S. Geological Survey Professional Paper 157, p. 71-72.

Reference (Deposit): Eisenhauer, R. C., 1932, Preliminary report on the property of the Utica Mining Company: unpublished geological report for the Utica Mining Company.

Reference (Deposit): Tucker, W. B., 1914, Calaveras County, Gold Cliff Mine: California State Mining Bureau, 14th Annual Report of the State Mineralogist, p. 98.

Reference (Deposit): Storms, W.H., 1900, The Mother Lode region - Calaveras County: California Mining Bureau Bulletin 18, p 111.

Reference (Deposit): Zimmerman, J.E., 1983, The Geology and structural evolution of a portion of the Mother Lode Belt, Amador County, California: unpublished M.S. thesis, University of Arizona, 138 p.

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California Gold

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