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Lincoln Consolidated Mines

Past Producer in Amador county in California, United States with commodities Gold, Silver
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Public Land Survey System information
  6. Commodities
  7. Materials information
  8. Alteration
  9. Mineral occurrence model information
  10. Host and associated rocks
  11. Nearby scientific data
  12. Geologic structures
  13. Ore body information
  14. Controls for ore emplacement
  15. Economic information about the deposit and operations
  16. Mining district
  17. Land status
  18. Ownership information
  19. Bibliographic references
  20. General comments
  21. Reporter information

Geologic information

Identification information

Deposit ID 10310639
Record type Site
Current site name Lincoln Consolidated Mines
Alternate or previous names Union Mine, Wildman Mine, Mahoney Mine

Comments on the site identification

  • The Lincoln Mine is located one mile southeast of Amador City in the famous Mother Lode Gold Belt in the Sierra Nevada foothills of western Amador County. While the mine is technically in the smaller Sutter Creek district, the uniform nature of gold mineralization with neighboring districts has caused some authors to consolidate this district with the Jackson - Plymouth district (Clark, 1970). The Jackson-Plymouth District was the most productive district of the Mother Lode belt with an estimated total production of about $180 million (Clark, 1970). The Lincoln Mine for many years was one of the most productive in the state and is credited with being the source of much of Leland Stanford's wealth that he later used to partner in the construction of the Central Pacific Railroad, and to found Stanford University.

    The mine included the Lincoln, Stewart, and Belmont claims. It developed typical Mother Lode northerly trending and easterly dipping hydrothermal quartz veins carrying free milling gold and auriferous sulfides within a narrow band of the Mariposa Formation slate which trends northward through western Amador County. Secondary ores included low-grade auriferous greenstone and amphibolite schist. The principle producing vein was the Lincoln vein which produced rich ore to a depth of 350, at which depth the vein was faulted out and could not be relocated. However, by this time, the Lincoln the mine had produced about $2.2 million (Clark, 1970).

    In 1906, the Lincoln Mine acquired the adjoining Wildman - Mahoney Mine and consolidated it with their operations, renaming the combined operations the Lincoln Consolidated Mines. Little new ore was found on the Lincoln, Wildman, or Mahoney claims and the mines were shut down in 1912.

Geographic coordinates

Geographic coordinates: -120.80618, 38.40027 (WGS84)
Elevation 402
Location accuracy 100(meters)
Relative position The Lincoln Mine is located about 1/3 mile north of Sutter Creek, California

Site location context

Political divisions (FIPS codes)

Amador(county)

California(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Amador City(quadrangle 1:24,000 scale)

San Andreas(quadrangle 1:100,000 scale)

Sacramento(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Upper Mokelumne(hydrologic unit)

San Joaquin(hydrologic accounting unit)

San Joaquin(hydrologic subregion)

California(hydrologic region)

Geographic areas

Country State County
United States California Amador

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 006N 011E 6,7, 8 NW/4 SE/4 California

Comments on the location information

  • Location selected for latitude and longitude is the Lincoln Mine shaft symbol as shown on the USGS 7.5 minute Amador City quadrangle

Commodities

Commodity Importance
Gold Primary
Silver Secondary

Comments on the commodity information

  • Commodity Info: Gold was 800 fine
  • Ore Materials: Freemilling coarse and fine gold in quartz with associated auriferous pyrite and arsenopyrite

    Hydrothermally altered slate, greenstone, and amphibolite schist wallrock containing enough disseminated auriferous pyrite to consytitute low-grade ore (`gray ore?)
  • Gangue Materials: Quartz, calcite, ankerite, sphalerite, chlorite, sericite

Materials information

Materials Type of material
Gold Ore
Arsenopyrite Ore
Pyrite Ore
Quartz Gangue
Calcite Gangue
Ankerite Gangue
Sphalerite Gangue
Chlorite Gangue
Sericite Gangue

Alteration

  • (Local) HWall rocks hydrothermally altered, having been partially to completely converted to ankerite, sericite, quartz, pyrite, arsenopyrite, chlorite, and albite. Locally, greenstone bodies adjacent to the quartz veins contain enough disseminated auriferous pyrite in large enough bodies to constitute low-grade ore.

Mineral occurrence model information

Model code 273
USGS model code 36a
Deposit model name Low-sulfide Au-quartz vein
Mark3 model number 27

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Metasedimentary Rock > Slate
    Rock unit name Mariposa Formation
    Stratigraphic age (youngest) Late Jurassic
  • Host or associated Host
    Rock type Metamorphic Rock > Metavolcanic Rock > Mafic Metamorphic Rock > Greenstone
    Rock unit name Mariposa Formation
    Stratigraphic age (youngest) Late Jurassic

Nearby scientific data

(1) -120.80618, 38.40027
ListMap

Economic information

Geologic structures

Type of structure Local
Structure description Melones Fault zone
Type of structure Regional
Structure description Bear Mountains Fault zone, Melones Fault Zone

Ore body information

  • General form Tabular, pinch and swell

Controls for ore emplacement

  • Ore shoots within mesothermal gold bearing quartz veins, and as disseminated auriferous sulfides in greenstone

Comments on the geologic information

  • REGIONAL GEOLOGY

    The Lincoln Mine is located 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. Locally, the Mesozoic rocks are capped by erosional remnants of Eocene auriferous gravels and once extensive volcanic rocks of Tertiary age. 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. In Amador County, the structural belts are internally bounded by the Melones and Bear Mountains fault zones. Schweickert and others (1999) provide one interpretive overview of the regional geology of this part of the Sierra Nevada.

    Gold deposits in the Plymouth - Jackson district occur within the north and northwest trending mile-wide Mother Lode Belt, which is dominated by gray to black slate of the Upper Jurassic Mariposa Formation and associated greenstone and amphibolite schist bodies assigned to its Brower Creek Volcanics member. In Amador County, the Mother Lode Belt approximately parallels Highway 49 southeastward from Plymouth through the town of Jackson. The geology of this segment has been mapped by Zimmerman (1983) and Duffield and Sharp (1975). The lode gold deposits along this stretch are responsible for most of the gold production in the county, which has been reported to be 7.68 million ounces (Koschman and Bergendahl, 1968). Clark (1970) placed the value of this production at $180 million. The Amador County portion of the belt was one of the most productive gold mining areas in the United States, and the Plymouth - Jackson district in Amador County was the most productive part of the belt.

    The Mariposa Formation contains a distal turbidite, hemipelagic sequence of black slate, amphibolite, schist, and fine-grained tuffaceous rocks, and volcanic 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. Massive greenstone of the Upper Jurassic Logtown Ridge Formation lies west of the Mother Lode Belt. The contact between the Logtown Ridge and Mariposa Formation is generally gradational (Zimmerman, 1983). The Logtown Ridge Formation consists of over 9,000 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. Metasedimentary rocks, chiefly graphitic schist, metachert, and amphibolite schist of the Calaveras Complex (Carboniferous to Triassic) are to the east.

    Mother Lode Gold Quartz Veins
    Mother Lode-type veins fill voids created within faults and fracture zones. The Mother Lode Belt consists of a vein system ranging from a few hundred feet to a mile or more in width. The vein system consists of a fault zone containing several parallel veins separated by hundreds of feet of highly altered country rock containing small quartz veins and occasional bodies of low-grade ore. Veins are generally enclosed within numerous discontinuous fault fissures within Mariposa Formation slate, associated greenstone, amphibolite schist, or along lithologic contacts. Mineralized fault gouge is abundant.
  • Mineralization is characterized by steeply dipping massive gold-bearing tabular quartz veins striking north to northwest and dipping between 50 to 80? east. Veins are discontinuous along both strike and dip, with maximum observed unbroken dimensions of 6,500 feet in either direction (Zimmerman, 1983), but individual veins more commonly range from structures 3,000 feet long and 10 to 50 feet wide to tiny veinlets. In rare instances, veins are known to reach as much as 200 feet thick (Keystone Vein). Veins may be parallel, linked, convergent, or en echelon, and commonly pinch and swell. Few can be traced more than a few thousand feet. At their terminations, veins pass into stringer zones composed of numerous thin quartz veinlets or into gouge filled fissures (Knopf, 1929).

    Ores consist of hydrothermally deposited minerals and altered wall-rock inclusions. Gold occurs as free gold in quartz and as auriferous pyrite and arsenopyrite. Quartz is the dominant mineral component in the veins, comprising 80-90% or more with ankerite, arsenopyrite, pyrite, albite, calcite, dolomite, sericite, apatite, chlorite, sphalerite, galena, and chalcopyrite in lesser amounts of a few percent or less. Cumulative sulfides generally range 1% - 3% of the rock (Carlson and Clark, 1954; Zimmerman, 1983).

    Ore grade material is not evenly distributed throughout the veins, but was localized in ore shoots, which tend to occur at vein intersections, at intersections of veins and shear zones, or at points where the veins abruptly change strike or dip (Moore, 1968). Ore shoots generally display pipe-like geometries raking steeply in the veins at 60-90%. Horizontal dimensions of the ore shoots are commonly 200-500 feet, but pitch lengths were often much greater, and often nearly vertical. Pockets of high grade ore are relatively abundant. Single masses of gold containing over 2,000 ounces and single pockets containing more than 20,000 ounces have been found. Silver is subordinate. Gold fineness averages 800.

    While most of the Mother Lode ore shoots mined have been less than 300 feet in strike length, many have extended down dip for many thousands of feet. In the deeper mines, mining continued to almost 6,000 feet on the dip of the vein with no evidence of bottoming. Cessation of operations in the deep Kennedy (5912') and Argonaut (5570') mines was caused by increasing costs at the greater depths rather than an absence of ore. Milling ore was generally low to moderate in grade (1/7 to 1/3 ounce per ton).

    Alteration
    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 (altered volcanic rocks) adjacent to the quartz veins contain enough disseminated auriferous pyrite in large enough bodies to constitute what has been called "gray ore". Altered slate wallrock 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 which 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 (Moore, 1968).
  • Ore Genesis

    Several mechanisms have been suggested as the source of the Mother Lode gold deposits. The most widespread belief is that plutonic activity magmatically differentiated vein constituents or provided the heat to circulate meteoric fluids or to metamorphose the country rocks to liberate the vein constituents. Knopf (1929) proposed that carbon dioxide, sulfur, arsenic, gold, and other constituents were emitted from a crystallizing magma but the components were carried by meteoric water in a circulation system driven by plutonic heat. Most theories suggest that gold deposits formed at temperatures of 300 to 350 degrees centigrade with a possible magmatic or metamorphic origin.

    Zimmerman (1983) proposed that the Mother Lode veins were generated by and localized near a major late Nevadan shear zone, the mechanism of ore genesis being the shearing and redistribution of mass within a major fault zone. He suggested that the early reverse faults had strike slip component, which is evident in the correlation of expected strike-slip dilatant zones with the geometries and steeply raking attitudes of the ore shoots. Fault movement and shearing would cause recrystallization of the rocks within the fault zone, releasing the more mobile elements including gold and most of the other vein constituents. Moreover, the heat generated by shearing would contribute to the metamorphism of the rocks in the fault zone and cause fluid circulation in the fault zone. Mineral laden auriferous fluids generated by this shearing channeled into the fault fracture system into dilatant zones, which represented avenues of increased flow and lower strain

    LOCAL GEOLOGY

    Metavolcanic and metasedimentary rocks of the Mariposa Formation host the gold-bearing veins in the Lincoln Mine. These rocks make up a northwesterly striking, nearly vertical dipping package approximately 1 mile wide consisting of black, thinly laminated carbonaceous clay slate with occasional layers of fine grained greywacke and interbedded units of greenstone.

    The gold bearing quartz veins are all localized within steeply dipping foliated shear zones in the slate and greenstone units. Veins are not conformable with the foliation but cut across the foliation at a slight angle. The tabular veins have a sinuous northwestererly strike. Unlike other documented Mother Lode veins, the Lincoln veins dip to the west in shallow workings, but at depth the veins roll to an eastward dip similar to the other productive veins in the district (Hazlitt and Russell, 1990)

    The main vein (Lincoln vein) in the Lincoln Mine comprises the western branch of the Mahoney vein system, which was the principal vein in the adjoining Wildman - Mahoney Mines to the south. About one mile north of the Mahoney Shaft, the Mahoney vein spit, the western branch extending into the Lincoln Mine. The Lincoln vein extended to a depth of only 350 feet, below which the vein was faulted out and could not be found again. At the surface, the Lincoln vein is not expressed as a large quartz outcrop, but as a series of small veins covering about 100 feet. On the 200-foot level, these stringers merge into one well-defined massive quartz vein 40 feet thick, with gouge sometimes on one wall and sometimes on the other (Brown, 1890). The best paying ore was from the ribbon rock on the footwall at the depth where the vein became well defined.
  • The Lincoln vein shows evidence of post-mineralization, steep easterly dipping, reverse fault movement in the plane of the vein. The fault zone is marked by a zone of fracture and shearing 4 to 6 feet wide. To the east of the fault plane, the schist's and slate country rock have an easterly dip. On the foot wall, however, the veins and the schist, slate and greenstone country rock dip strongly westward to about the 800 foot level where dips become almost vertical, and by the 1200 foot level, dips have nearly assumed the easterly dips displayed in the hanging wall (Storm, 1900). In places, the quartz can be faulted out completely with less than an inch of gouge remaining. Quartz filled extension fractures and horsetailing quartz veins occur in the walls of the major structures. Splays off the major veins are common, resulting in areas of multiple veins. Vein splits or intersections localize higher-grade ore shoots and also result in areas of greater width and tonnage. Higher-grade ore zones are also found where the boundaries between rock units are cut by the vein structures. The regional stress field during shear zone development, alteration, and mineralization is believed to have been compressional with accompanying reverse faulting and strike-slip faulting.

    Ore bearing veins are typically white late stage quartz, ankerite, and associated sulfides. Free gold occurs in the quartz veins and vein selvages as free milling grains of gold and as fracture filling within coarse sulfide grains. Sulfides, principally pyrite and arsenopyrite, comprise about 2% of the ore with minor amounts of galena, sphalerite, and chalcopyrite. The higher-grade quartz veins usually show black banded ore ribboned quartz structures parallel to the vein walls. Some of these structures display striated or slickensided surfaces. Free gold is commonly present in ribboned structures which are composed of parallel layers of quartz, crushed slate, pyrite, arsenopyrite, chlorite, and sericite (Hazlitt and Russell, 1990). The purity of the free gold is greater than 800 fine (Hazlitt and Russell, 1990). The shallowest oxidized ores are said to have yielded as much as $15/ton.

    Wall rock alteration is pervasive. Locally, the shear zones have been carbonate altered to a mixture of ankerite and sericite. Usually the higher-grade portions of the veins have intensely carbonate-altered gouge which are cut by narrow quartz veinlets and are impregnated with arsenopyrite and pyrite and comprise a low grade "gray ore." Carbonate alteration is also cut by the veins but is more proximal to the veins and may have accompanied the early stage of vein formation (Hazlitt and Russell, 1990).

    A generalized cross section through the Lincoln Mine is shown by Storm (1900), figure 26.

Economic information about the deposit and operations

Operation type Underground
Development status Past Producer
Commodity type Metallic
Significant Yes
Discovery year 1851

Mining district

District name Sutter Creek

Land status

Ownership category Private
Area name Amador County Planning dept.

Ownership information

  • Type Owner
    Owner Sutter Gold Mining Inc.
    Home office 877 N. 8th W.\nRiverton, WY 82501 USA\nPH: 307-856-9271
  • Type Operator
    Owner Sierra Nevada Recreation Corp.
    Home office P.O. Box 78, Vallecito, CA 95251\n866-762-2837 or 209-736-2708

Comments on the workings information

  • Description of Mine Workings

    The following workings were reported by the California Mining Bureau for the Lincoln Mine on August 19, 1914.

    Lincoln Mine Workings
    Lincoln shaft - 2000 feet at 63? incline (located 1000' NW of Mahoney shaft)
    500 foot level - drift N 144' then crosscut E 80' from drift N, crosscut W 104' with drift N 160' then crosscut W 200' and drift N 120' on 500' level S of shaft crosscut W 440'.
    650 foot level - crosscut W from shaft 150' then drift S 360' from which point crosscut W 120', then drift N 160' and crosscut W 200' and drift N 160'.
    800 foot level - crosscut W from shaft 120' and crosscut E from shaft 125'
    1200 foot level - drift S from shaft 200' with crosscut E 240 and W 40' at 25' S of shaft in south drift crosscut driven west 40 ' then drift N 360 ' and S 320' and W crosscut is extended 480' W into footwall.
    1950 foot level - drift S 2240' and crosscut driven N of shaft 640' W into footwall. (Level driven S under Wildman and Mahoney ore body).

    Wildman Mine workings
    Wildman shaft - 1400 feet at 72? incline
    Emerson shaft - 619' vertical (located 900' E of Wildman shaft)
    400 foot level - 720? S crosscut E 50' on north side of shaft, drift N 200'
    500 foot level - crosscut W 60' to vein on north side of shaft, with drift S 400' and drift N 180'.
    600 foot level - crosscut W 80' to vein, drift N 180'
    700 foot level - crosscut W 40', drift S 680'- 80' on N side of shaft on 700' level, crosscut W 140' and crosscut E 640'
    800 foot level -240'N, 80' S
    900 foot level - 840'N, 140' S
    1,000 foot level - 240'N, 140' S
    1,100 foot level - 300' N, 160' S
    1,200 foot level - 340' N, 280' S
    1,300 foot level - 260' N, 500' S

    Mahoney Mine workings
    Mahoney shaft - 1200 feet at 62? incline (located 960' NW of Wildman shaft)
    200 foot level - 240' N, 420' S
    300 foot level - 180' N, 425' S
    600 foot level - 260' N, 260' S
    800 foot level - 0' N , 550' S
    900 foot level - 120' N, 820' S
    1,000 foot level - 0'N , 720' S
    1,200 foot level 80' N, 100' S
    Mahoney workings are connected with the Wildman workings on the 600', 800', 900', and 1000' levels.

    Emerson Shaft - vertical to 616 feet deep.

    Workings in slate were difficult to maintain and required heavy timbering or other ground support. To accommodate this, large stations were cut and additional sets were placed outside the main station sets with open lagging spaced 8 - 10 inches apart. Under pressure from ground swelling the light lagging would bend and eventually break, giving sufficient warning before significant damage to the main members of the set (Storm, 1900). The usual stoping method in slates was square set with almost immediate backfilling. Gray ore and amphibolite schist were much more competent, and haulage ways and development openings in unfractured ground were untimbered.

Comments on other economic factors

  • Clark (1970) reported that, independently, the Lincoln Mine produced $2.2 million and the combined Wildman- Mahoney Mine $5.0 million.

Comments on development

  • Most of the important lode gold deposits in Amador County Mother lode were discovered in the 1850s while rich Tertiary placer deposits were being worked. The Lincoln Mine was located in 1851 and originally named the Union Mine. It was the first lode mine discovered at Sutter creek.

    Upon Leland Stanford's arrival in the Mother Lode, he bought into and became a partner in the Union Mine which he later renamed the Lincoln Mine. The mine became one of the principal sources of Leland Stanford's fortune, having owned the controlling majority of shares between 1859 and 1872. In its early years of operations, however, problems plagued the mine and he was ready to sell his interest for $5,000, but could not find a buyer. Fortunately, the mine foreman talked him out of it. Shortly after, a big strike was made and the Lincoln Mine became a bonanza. In the 1860s, the Lincoln Mine had two shafts, one 669 feet deep and another at 270 feet deep, and is said to have produced 3500 tons of ore annually from 1851-1867, except for two years (Logan, 1927). Ore was worked in a 20 stamp mill. Stanford became a wealthy man and went on to become a US senator, California Governor, founder of Stanford University, and partner in the central Pacific Railroad. He ultimately sold his interest for $400,000. The mine paid handsomely to a depth of 350 feet, but at that depth a fault cut the vein and it was lost (Storm, 1900). The shaft was deepened to 807 feet without finding any additional ore and the mine was shut down. The exact production to this depth is unknown, but has been estimated at $2.2 million (Logan, 1927).

    After lying idle about 30 years, the Lincoln Mine was reopened in 1898 by the Lincoln Gold Mine Development Company. The old shaft was repaired, the workings cleaned out, and sinking resumed in 1899. Settling around the old shaft caused a misalignment of the shaft, so much of the surrounding debris was excavated and the upper shaft had to be timbered in square sets to keep it aligned and open. By 1900 the shaft was at 1260 feet with a drift several hundred feet long on the 500 foot level and a crosscut run east and west about 200 feet north of the shaft. Three ore bearing veins were encountered in the crosscut, one of which was drifted 168 feet. This vein was 110 feet west of the gangway. The second vein was 135 feet farther west and was from 6 to 20 feet wide. It was developed by a drift 200 feet long. The third vein lies another 70 feet farther west near the contact of amphibolite schist and Mariposa Formation black slate.

    In 1906, the Lincoln Gold Mine Development Company acquired the neighboring Wildman-Mahoney Mine and merged it with their operations. The Wildman-Mahoney Mine consisted of two previously independent mines (Wildman and Mahoney mines), which merged after the Wildman Mining Company's purchase of the Mahoney Mine in 1894. The combined operations were renamed the Lincoln Consolidated Mines. The Emerson shaft was sunk 1000 feet east of the Wildman Shaft to cut the Wildman vein. The Lincoln shaft was also deepened to 2000 feet on a 63? incline, and a drift was run south over 2200 feet passing through the Mahoney claim and to a point below the Wildman 1400 foot shaft. Long crosscuts were run into the footwall on the 500, 1200, and 1950 foot levels of the Lincoln Shaft, and on the 1200 foot level one was run into the hangingwall, all without finding any new ore (Logan, 1927).
  • Costs escalated during the early 1900s and the Lincoln Consolidated Mines were shut down in 1912. By 1913, the properties included the Lincoln, Wildman, Mahoney, South Mahoney, Belmont, and Lincoln Mill site, and comprised 383 acres with 4200 feet on the vein (Tucker, 1914). At this time it had four shafts: the Lincoln Shaft at 2000 feet deep on a 63? incline, the Wildman Shaft at 1400 feet deep on a 72? incline, the Mahoney Shaft at 1200 feet deep on a 62? incline, and the vertical Emerson Shaft at 616 feet deep. The Lincoln Consolidated Mines were sporadically worked until 1924. Only foundations and the dump of the original Lincoln Mine remain.

    In the 1980's, the Lincoln Consolidated Mine properties, as well as neighboring properties were acquired by Callahan Mining and Pancana Mining (American Barrick) with the intent of exploring and possibly reopening several old Mother Lode Gold mines between Sutter Creek and Amador City as a consolidated operation. The combined properties extend from the Lincoln Mine on the southern edge of the property to the Keystone Mine at the northern edge of the property, a distance of 1.5 miles and comprises 535 acres. Callahan started exploration in 1983 and had drilled 30 core holes by 1987, at which time the properties, by then known as the Lincoln Project were sold to Meridian Gold. Meridian continued exploration efforts brining the total surface core holes to 89 and adding 63 core holes underground. In total 64,700 feet of exploratory core holes had been drilled. FMC Gold subsequently acquired the Lincoln Project when it bought Meridian Gold in May, 1990 (Hazlitt and Russell, 1990).

    Meridian identified several probable ore shoots and drove drove an exploration decline paralleling the strike of the veins. As of a 1990, a 2850 foot decline (12' high x 15' wide), 2400 feet of crosscuts, and four raises had been driven. Underground exploration drilling, raising, and sampling resulted in confirmation and additions to the surface drilled resources. Two ore zones were identified, the Lincoln Zone on the southern end of the property and the Comet Zone on the northern end of the property. Both zones are paralleled by the decline with nearly all of the underground work focusing on the "M" vein in the Comet Zone. Reserve estimates were approximately 600,000 tons containing an estimated 200,000 ounces of gold. Meridian planned to mine all of these reserves within 600 feet of the surface (Hazlitt and Russell, 1990).

    In 1991, the Lincoln Project was purchased by U. S Energy Corp (and subsidiaries) and Seine River Resources. In 1994, the Sutter Gold Mining Company was incorporated to develop, permit, and mine the identified Lincoln Zone and Comet Zone ore bodies. The project was permitted to mine and mill up to 1000 tons per day and outfitted as a modern underground mine. The project was on hold for several years awaiting approval of water quality and environmental permits, which were finally issued in early 2006. Until mining operations commence, the property is being operated as an underground mine tour with retail shop to defray property holding costs.

Reference information

Bibliographic references

General comments

Subject category Comment text
Deposit The Lincoln Mine produced from typical Mother Lode type low sulfide mesothermal gold-quartz veins. The principle vein was the Lincoln vein striking NNW-SSE. Unlike most Mother Lode veins, the Lincoln vein dipped to the west in shallow workings before assuming a more typical steep easterly dip in deeper workings. Primary vein ore consisted of free gold and auriferous pyrite and arsenopyrite within pipe-like steeply raking ore shoots. Ores shoots were typically richer at vein intersections and at lithologic contacts. Gold values were typically low to moderate in grade, averaging 1/7 to 1/3 ounces of gold per ton. Secondary, low grade, ores also occurred as hydrothermally altered slate, greenstone, and amphibolite schist wallrock containing disseminated auriferous pyrite ('gray ore").

Reporter information

Type Date Name Affiliation Comment
Reporter 10-MAR-2006 Downey, Cameron (Higgins, Chris, T.) California Geological Survey CGS (Formerly CDMG)
Editor 01-SEP-2007 Schruben, Paul G. U.S. Geological Survey Converted from S&A FileMaker format to Oracle. Edit checks on rocks, units, and ages with Geolex search, and other fields.

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