Beebe (Beebe-Woodside-Eureka) Mine

Site Name

Primary: Beebe (Beebe-Woodside-Eureka) Mine
Secondary: Woodside
Secondary: Eureka
Secondary: Iowa
Secondary: Brooklyn

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Commodity

Primary: Gold
Tertiary: Silver

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Location

State: California
County: El Dorado
District: Georgetown District

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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: El Dorado County Planning Dept.

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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: Underground
Discovery Year: 1848
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

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Structure

Type: L
Description: Melones Fault Zone

Type: R
Description: Melones Fault Zone

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Alterations

Alteration Type: L
Alteration Text: Silicification of amphibolite schist

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Rocks

Name: Slate
Role: Host
Description: black
Age Type: Host Rock
Age Young: Late Jurassic

Name: Amphibole Schist
Role: Host
Description: schist
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
Gangue: Quartz
Gangue: Calcite
Gangue: Amphibolite

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Comments

Comment (Geology): REGIONAL GEOLOGY The Beebe Mine is within the Sierra Nevada 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. All the belts are characterized by extensive faulting, shearing, and folding (Earhart, 1988). In the El Dorado County area, gold deposits occur in the West Belt, the Mother Lode Belt, and the East Belt. The Mother Lode Belt is responsible for most of the gold produced in the county. There has also been substantial gold produced from the West Belt and East Belt (Clark and Carlson, 1956). The West Belt consists of widely scattered gold deposits located west of the Mother Lode vein system. Gold occurs in irregular quartz veins in schist and granitic rocks, altered mafic rocks, and as gray ore in greenstone. The West Belt has been further divided by some authors into an eastern component composed of an ophiolitic melange and a western component composed of Jurassic rocks of the Copper Hill volcanics (Duffield and Sharp, 1975; Saleeby, 1982; Clark, 1964). The Copper Hill volcanics consist of mafic to felsic flows and pyroclastic rocks that are metamorphosed to greenschist and amphibolite facies. The Bear Mountains fault zone separates the melange from the Copper Hill volcanics. The Mother Lode Belt 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, amphibolite, schist, and 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 Belt mineralization is generally characterized by steeply dipping gold-bearing quartz veins that traverse western El Dorado County. The belt trends north through Nashville, northeast through Placerville, and northwest to Garden Valley. The Mother Lode veins are generally enclosed in Mariposa Formation slate with associated greenstone. The 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, and sericite (Clark and Carlson, 1956).

Comment (Commodity): Commodity Info: Reported ore values ranged from about $3 to $64 per ton with small quantities of high-grade specimen ore commanding as much as $12,000. Reported sulfide content ranged as high as 6 ?%.

Comment (Commodity): Ore Materials: Free milling gold and auriferous sulfides

Comment (Commodity): Gangue Materials: quartz, calcite, amphibolite schist

Comment (Deposit): Unlike the typical Mother Lode gold quartz veins, the Beebe Mine deposits consist of zones of alteration within the hanging wall amphibolite schist along fracture zones. Circulation of hydrothermal fluids migrating along fractures within sericite and chloritic amphibolite schist resulted in the replacement and silicification of the hanging wall into a gradational zone of sericite quartz schist bearing free gold and auriferous pyrite. Further silicification converted the rock into a white, fine granular replacement quartz vein with plentiful cubes of distributed auriferous pyrite. Replacement, silicification, and gold values diminish with distance from the footwall. Footwall rocks are unmineralized. Reported ore values ranged from about $3 to $64 per ton with small quantities of high grade specimen ore commanding as much as $12,000. Reported sulfide content ranged as high as 6.5%.

Comment (Economic Factors): No information is readily available regarding production from the Woodside-Eureka claims between their discovery in 1848 and their consolidation with the Beebe mine in 1931. During operation of the Beebe Mine by the Beebe Mining Company between 1932-1939, 306,241 tons of ore yielded $1,200,465 in gold. Clark (1970) credits the Beebe Mine with a total production of approximately $2 million. Ore from the Beebe vein was low grade and high in sulfides, carrying a reported 6.5? sulfides. The Eureka vein produced a somewhat higher average grade of ore than the Beebe vein, with ore reportedly averaging about 0.24 ounces of gold per ton. Reported average values for milling ore from the Woodside vein vary widely ranging from $3 - $63.80 per ton, with a wheelbarrow full of high grade specimen ore commanding $12,000.

Comment (Location): Location selected for latitude and longitude is the Beebe Mine symbol on the USGS 7.5 minute Georgetown quadrangle

Comment (Development): The Beebe Mine, located on the north side of Georgetown, was one of the larger sources of gold in El Dorado County. It consisted of several claims, some of which were discovered and worked independently before their consolidation with the Beebe Mine in 1932. These claims included the Woodside-Eureka claims, and the Brooklyn, East Lode, Iowa claims (Clark and Carlson, 1956). Woodside-Eureka Woodside-Eureka Mine, which worked its namesake claims, was discovered in 1848 and was worked from 1848 to about 1900. Little information is available about the independent operations of the Woodside-Eureka Mine. By 1866, it was opened to a depth of 110 feet and by 1867 to a depth of 210 feet. In 1867, it had a 5 stamp mill and had produced considerable "high grade" ore. It was reopened by the Woodside-Eureka Company in 1906 who proceeded to unwater the Eureka Shaft. The mine was again idled in 1908. By that time, the deeper shaft was sunk to 240 feet with levels at 85 feet and 200 feet. On the 200 foot level, short drifts were run north and south. Another old shaft was reportedly 180 feet deep (Logan, 1934). Considerable water was reported in the Woodside workings and this was given as the main reason for stopping work (Logan, 1934). Beebe The Beebe claim itself was prospected in 1917 to a depth of 250 feet, but remained unworked thereafter until 1931, when Alexander Wise took it over. The Beebe Gold Mining Company was formed to develop the property and adjoining claims, and a plant was built containing two Hadsell mills and cyaniding equipment. Mining had been going on only a short time when Wise died and the property was taken over by the Pacific Mining Company (Logan, 1934). By 1938, the Hadsell mills had been replaced by two 7 foot by 36 inch Hardinage conical ball mills. Overflow from the classifier below the ball mills passed to 24 Kraut flotation cells. The concentrate from these was thickened to 50% solids, ground in a 5 foot by 8 foot Marcy mill and treated with cyanide in two 30 foot by 8 foot Devereaux agitators. After passing through 3 thickeners, the pregnant solution was filtered and the gold precipitated by zinc dust (Logan, 1938). From 1932 until 1939, the Beebe Gold Mining Company operated the mine and removed 306,241 tons of ore that produced $1,200,465 in gold. A crew of about 45 men were employed at mine by 1934 and the mine was were producing and milling 325 tons a day. This high efficiency resulted in a low mining cost reported to be $1.17 per ton and allowed the working of the generally low grade Beebe ore (Logan, 1934). By 1934, the Pacific Mining Company had extended the Beebe 250 foot level under the Eureka and have sunk a winze to the 500 foot level on the Eureka vein (Logan, 1934). Ore had been stoped in the Eureka to 130 feet in depth but the output from this is not definitely known. By 1938, a new shaft in the vein had been raised from the 500 foot level to the surface about 190 feet from the old one. A winze has been sunk 200 feet from the 500 foot level at a point 500 feet northeast of the main shaft and by July, 1938, ore was being stoped from the 600 foot level in the Eureka claim. A length from 500 to 600 feet along the strike was worked from the surface to a depth of 250 feet. On the 370 foot level, a length of about 700 feet was drifted in ore, of which 65% was mined, the balance being left in pillars. The stoped width varied from 5 feet to 50 feet and averaged 12-15 feet (Logan (1938). The Mine was closed in 1939. After 1939, a little gold was found while cleaning up.

Comment (Geology): At Garden Valley, the Mother Lode Belt splits. The west branch extends northwest through Greenwood, and the east branch extends north through Georgetown to the Georgia Slide area (Busch, 2001). In this area, there is a north- and northwest-trending belt of slate, with greenstone and green schist to the west and mica schist, slate, quartzite, amphibolite, and serpentine to the east (Clark, 1970). In the area of the Georgetown District, the black slates contain lenses of amphibolite schist in which the quartz veins of the Beebe and associated mines occur. In the far northern part of the district, particularly in the area of Georgia Slide, orebodies have been described as "seam deposits". Unlike the typical Mother Lode veins, seam deposits consist of narrow gold bearing quartz veinlets within slate, amphibolite, or chlorite schist. The richest portions of seam deposits are, for the most part, near the intersections of two or more systems of veinlets, or where one system intersects a larger quartz vein (Logan, 1934). Seam deposits were frequently heavily weathered and friable to depths of 100-150 feet, allowing the rich oxidized zone to be worked by hydraulic mining methods. When more competent unweathered rock was reached, lode mining methods were employed. The Melones Fault zone separates the Mother Lode Belt from the East Belt. The East Belt lies in the south central part of El Dorado County approximately 15 miles east of the Mother Lode belt. The East Belt traverses the county from the southern county line, north through Omo Ranch and Grizzly Flat, and apparently terminates near the Hazel Creek Mine east of Jenkinson Reservoir (Busch, 2001). The Eastern Belt is dominantly argillite, phyllite and phyllonite, and chert of Paleozoic-Mesozoic age. The phyllite and phyllonite are dark to silvery gray. The chert is mostly thin bedded with phyllite partings. Other rocks in the Eastern Belt include a Jurassic granodiorite pluton near the Cosumnes River and small bodies of Jurassic serpentinite, gabbro, diorite, and limestone. The Paleozoic metasedimentary rocks of the Eastern Belt have been assigned to the Shoo Fly Complex by most investigators. Lode deposits of the East Belt consist of many individual gold-bearing quartz veins enclosed in 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 (Clark and Carlson, 1956) LOCAL GEOLOGY The Beebe Mine consists of the consolidation of several adjacent claims that worked different orebodies named after the respective mine or claim. Unlike typical Mother Lode fracture filling quartz veins, the principle orebodies in the Beebe Mine consisted of zones of replacement and silicification of amphibolite wallrock that resembled conventional fissure filling veins.

Comment (Geology): The Beebe "vein" is a silicified and mineralized zone of sericite and chloritic amphibolite schist within the Calaveras Complex. It strikes about N 20? E and dips 70?-80? east. Hydrothermal fluids migrating along a fracture resulted in the replacement and silicification of the amphibolite schist hanging wall into a gradational zone of light colored sericite quartz schist bearing free gold and auriferous pyrite having a width of 5-50 feet but averaging 25 feet wide. Further silicification converted the rock into a white, fine granular replacement quartz vein with plentiful cubes of distributed pyrite that characterizes the best ore (Hershey, 1934, unpublished geological report). Replacement, silicification, and gold values diminish with distance from the footwall. On the footwall is an unmineralized, but highly altered basic dike 10 inches to 2 feet wide, which forms a convenient footwall to the stopes of the Beebe vein (Hershey, 1934, unpublished geological report). Underlying the dike, footwall amphibolite is unmineralized. Ore from the Beebe vein was low grade and high in sulfides, carrying a reported 6.5% sulfides. Discussion of specific ore shoots is contained in an unpublished geologic report of the Beebe Mine contained in the files of the California Geological Survey Mineral Resource file No. 331-9748. The Eureka "vein" or orebody is also composed of a zone of replacement within amphibolite schist. The orebody is more perfectly silicified than other material in the vicinity and has coarser pyrite cubes that are more evenly spaced than in neighboring orebodies. The ore body is triangular in cross section, and terminated on the north by a vertical gouge seam, against which it is nearly 50 feet wide. About 120 feet south, it tapers to a point where the mineralized rock practically pinches out in green schist. The Eureka vein produced a somewhat higher average grade of ore than the Beebe vein. Ore was reported to average 0.24 oz per ton. Little information is available regarding the Woodside vein. The vein was reported to be 2 or 3 feet wide and enclosed in black Mariposa Formation slate. It was a producer of specimen ore in the early days and one wheelbarrow load of especially high-grade specimen material was reportedly worth $12,000 (Logan, 1934). Reported average values for milling ore vary widely ranging from $3 - $63.80 per ton.

Comment (Identification): The Beebe Mine is located within the Georgetown District in northwestern El Dorado County at the northeast end of the Mother lode Gold belt. The Beebe Mine includes neighboring leases and mines (including the Woodside-Eureka Mine and the Brooklyn, East Lode, Iowa claims), some of which were worked independently before their consolidation with the Beebe Mine in 1932. The mine is considered one of the larger gold producers in El Dorado County having produced an estimated $2 million from several replacement "veins" within amphibolite schist of the Paleozoic-Mesozoic Calaveras Complex.

Comment (Workings): By the time of its closure, the consolidated Beebe mine was developed by three shafts, the Eureka, old Beebe, and Beebe No. 2 shafts. Levels were driven at 130, 250, 370, 500, 600, and 700 feet. On the 370 foot level, a length of 700 feet was drifted in ore (Logan, 1938; Clark and Carlson, 1956). A winze was sunk from the 500 foot level to the 700 foot level. Shrinkage stopes were employed. A schematic (longitudinal projection) of the underground workings and stoped areas of the Beebe Mine is given by Clark and Carlson (1956) (Figure 16, page 407).

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References

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): Lindgren, W. and Turner, H.W., 1894, Placerville folio, California: U.S. Geological Survey, Geological Atlas of the U.S., folio 3.

Reference (Deposit): Logan, C.A., 1934, Mother Lode gold belt of California: California Division of Mines Bulletin 108, p. 17-19.

Reference (Deposit): Logan, C.A., 1938, Mineral resources of El Dorado County: California Division of Mines, 34th Report of the State Mineralogist, p. 217-218.

Reference (Deposit): Saleeby, J., 1982, Polygenetic ophiolite belt of the California Sierra Nevada; geochronological and tectonostratigraphic development: Journal of Geophysical research, v. 87, n0. 8, p. 1803-1824.

Reference (Deposit): Tucker, W.B., and Waring, C.A., 1916, Mines and mineral resources of El Dorado, Placer, Sacramento, and Yuba counties: California State Mining Bureau, 15th Report of the State Mineralogist, p. 300.

Reference (Deposit): Additional information on the Beebe Mine is contained in File No. 332-1429, 339-8904, and 331-9874 (CGS Mineral Resources Files, Sacramento)

Reference (Deposit): Busch, L.L., 2001, Mineral land classification of El Dorado County, California: California Geological Survey Open-File Report 2000-03.

Reference (Deposit): Clark, W. B., 1970, Gold districts of California: California Divisions of Mines and Geology Bulletin 193, p. 51.

Reference (Deposit): Clark, W.B. and Carlson, D.W., 1956, Mines and mineral resources of El Dorado County: California Division of Mines, California Journal of Mines and Geology, v. 52, p. 406-408.

Reference (Deposit): Duffield, W.A., and Sharp, R.V., 1975, geology of the Sierra Foothills melange and adjacent areas, Amador County, California: U.S. Geological Survey Professional Paper 827, 30 p.

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California Gold

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