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Lowell Hill Mining District, Nevada Co., California, USAi
Regional Level Types
Lowell Hill Mining DistrictMining District
Nevada Co.County
CaliforniaState
USACountry

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Key
Latitude & Longitude (WGS84):
39° 15' 31'' North , 120° 46' 26'' West
Latitude & Longitude (decimal):
Locality type:


Location and History: A former Au-Ag-Pt mining area, discovered before 1850, this district is in south-central Nevada County about six miles NE of Dutch Flat in secs. 5 to 8, 17 & 18, T16N, R11E, and in secs. 31 & 32, T17N, R11E, MDM. It includes the Remington Hill, Negro Jack Hill, and Liberty Hill areas. The district was hydraulicked from the middle 1850's through the 1870's, and Liberty Hill was worked again from around 1896 to 1915. The total output is unknown, but it exceeds $1 million (period values). Lindgren, in 1911, estimated that two million cubic yards had been removed and 16 million remained at Liberty Hill and that 1.75 million cubic yards had been removed and 6 million remained at Remington Hill. Other estimates of remaining gravel at Liberty Hill range from 6 to 10 million yards. Location selected for latitude and longitude by the USGS is the Mammoth Springs Mine portal symbol on the south side of Negro Jack Hill on the USGS 7 1/2-minute Washington quadrangle.

The placer deposits in the Lowell Hill District were placer-mined from the mid-1850s through the 1870s, with the Liberty Hill workings being worked again between 1886 and 1915. Hydraulic mining at Lowell Hill was hampered by the heavy overlying beds of clay. Drift mining was done at the Valentine and Swamp Angel mines.

Mineralogy: The native gold is fine to coarse gold and nuggets (900 fine). Gangue materials include quartz, metamorphic and ultramafic gravels and boulders. Accessory minerals include magnetite, ilmenite, zircon, pyrite, amphibole, epidote, chlorite, and siderite.

Geology: The deposits are in a southwest-trending Tertiary channel that joins the Dutch Flat channel. There is a lower well-cemented blue gravel that contains gabbro and serpentine boulders and yielded 18 to 23 cents (period values) a cubic yard. An upper quartz-rich gravel is in places covered by heavy clay. Bedrock is slate of the Blue Canyon Formation (Carboniferous) and some serpentine.

Within the district, the Feather River Peridotite Belt narrows to less than a mile wide. Consequently, basement rocks consist of Calaveras Complex rocks to the west, ultramafic rocks and serpentinites of the Feather River Peridotite Belt, and slates of the Shoo Fly Complex of the Eastern Belt to the east, A large part of the district is overlain by volcanic rocks of the Valley Springs and Mehrten formations.

Basal Eocene Auriferous Gravels: The Lowell Hill District contains several separate placer deposits at Lowell Hill, Liberty Hill, Negro Jack Hill, and Remington Hill. By far, the most extensive of these workings are those at Lowell Hill where the auriferous gravels are exposed.

The channel gravels in this district were deposited by a small tributary that drained into a larger tributary of the ancestral Yuba River. This tributary flowed southwestward from the Remington Hill area to join the main tributary at Dutch Flat. The main tributary then flowed generally north-northwestward and deposited the placer gravels in the Dutch Flat, You Bet-Red Dog, Scotts Flat, and Blue Tent districts before joining the ancestral Yuba River in the North Columbia District.

Consistent with the Tertiary gravel deposits in neighboring districts, the deposits can be divided lithologically and texturally into lower and upper units. The thickness of the combined units at Liberty Hill is only 60 feet and equally divided between the two units. The lower unit, or blue lead of the early miners, rests directly on bedrock and contains the richest ores. Lower gravels are well-cemented, quartz-rich, and contain abundant gabbro and serpentinite boulders reflecting erosion of the ultramafic rocks of the Feather River Peridotite Belt bedrock. Lower gravels have been reported to yield between $0.18 and $1.43 per cubic yard.

In most of the workings, the upper unit gravels form the bulk of the deposits. This unit's thickness varies widely. Upper gravels are quartz-rich and much finer, with clasts seldom larger than pebble size and locally including interbeds of clay. Large-scale cross-bedding and cut-and-fill features are common. The upper gravels are considerably leaner than lower gravels, with a reported average yield of $0.24 ($35.00 ounce/gold) being reported at Liberty Hill.

The gravel deposits at Lowell Hill are overlain by a 30 foot layer of light colored clay.

Regional geologic structures include the Foresthill Fault and the Melones Fault Zone. Local structures include the Melones Fault Zone.

Ore deposits: Mineral occurrence model information: Model code: 119; USGS model code: 39a; BC deposit profile: C01. C02; Deposit model name: Placer Au-PGE; Mark3 model number: 54. Deposits are hosted in unconsolidated Tertiary sand and gravels. The ore bodies are irregular in form. Controls for ore emplacement included mechanical accumulation on irregular bedrock riffles and within river- and stream-channel lag gravels, bars, and point bar deposits. Local rocks include ultramafic rocks, chiefly Mesozoic, unit 2 (Western Sierra Nevada and Klamath Mountains)

Commodity Information: Upper gravels at the Liberty Hill workings averaged about $0.24 per cubic yard (@ $35/ounce). Lower gravels at the Liberty Hill workings are reported to have ranged between $0.18 and $1.43 per cubic yard (@ $35/ounce).

Production Statistics: The total production of the district exceeds $1 million (period values), but actual production figures are unknown. Lindgren (1911) estimated that 2 million cubic yards had been removed and that 16 million remained at Liberty Hill. He also estimated that 1.75 million had been removed and 6 million remained at the Remington Hill workings.

Regions containing this locality

North America PlateTectonic Plate

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Standard Detailed Strunz Dana Chemical Elements

Mineral List

Mineral list contains entries from the region specified including sub-localities

9 valid minerals.

Detailed Mineral List:

'Amphibole Supergroup'
Formula: AX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10310640.
'Chlorite Group'
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10310640.
Chromite
Formula: Fe2+Cr3+2O4
Epidote
Formula: {Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10310640.
Gold
Formula: Au
Localities: Reported from at least 6 localities in this region.
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10310640.
Ilmenite
Formula: Fe2+TiO3
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10310640.
Magnetite
Formula: Fe2+Fe3+2O4
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10310640.
Pyrite
Formula: FeS2
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10310640.
Quartz
Formula: SiO2
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10310640.
Siderite
Formula: FeCO3
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10310640.
Zircon
Formula: Zr(SiO4)
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10310640.

List of minerals arranged by Strunz 10th Edition classification

Group 1 - Elements
Gold1.AA.05Au
Group 2 - Sulphides and Sulfosalts
Pyrite2.EB.05aFeS2
Group 4 - Oxides and Hydroxides
Chromite4.BB.05Fe2+Cr3+2O4
Ilmenite4.CB.05Fe2+TiO3
Magnetite4.BB.05Fe2+Fe3+2O4
Quartz4.DA.05SiO2
Group 5 - Nitrates and Carbonates
Siderite5.AB.05FeCO3
Group 9 - Silicates
Epidote9.BG.05a{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Zircon9.AD.30Zr(SiO4)
Unclassified Minerals, Rocks, etc.
'Amphibole Supergroup'-AX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
'Chlorite Group'-

List of minerals arranged by Dana 8th Edition classification

Group 1 - NATIVE ELEMENTS AND ALLOYS
Metals, other than the Platinum Group
Gold1.1.1.1Au
Group 2 - SULFIDES
AmBnXp, with (m+n):p = 1:2
Pyrite2.12.1.1FeS2
Group 4 - SIMPLE OXIDES
A2X3
Ilmenite4.3.5.1Fe2+TiO3
Group 7 - MULTIPLE OXIDES
AB2X4
Chromite7.2.3.3Fe2+Cr3+2O4
Magnetite7.2.2.3Fe2+Fe3+2O4
Group 14 - ANHYDROUS NORMAL CARBONATES
A(XO3)
Siderite14.1.1.3FeCO3
Group 51 - NESOSILICATES Insular SiO4 Groups Only
Insular SiO4 Groups Only with cations in >[6] coordination
Zircon51.5.2.1Zr(SiO4)
Group 58 - SOROSILICATES Insular, Mixed, Single, and Larger Tetrahedral Groups
Insular, Mixed, Single, and Larger Tetrahedral Groups with cations in [6] and higher coordination; single and double groups (n = 1, 2)
Epidote58.2.1a.7{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Group 75 - TECTOSILICATES Si Tetrahedral Frameworks
Si Tetrahedral Frameworks - SiO2 with [4] coordinated Si
Quartz75.1.3.1SiO2
Unclassified Minerals, Mixtures, etc.
'Amphibole Supergroup'-AX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
'Chlorite Group'-

List of minerals for each chemical element

HHydrogen
H Amphibole SupergroupAX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
H Epidote{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
CCarbon
C SideriteFeCO3
OOxygen
O ChromiteFe2+Cr23+O4
O QuartzSiO2
O MagnetiteFe2+Fe23+O4
O IlmeniteFe2+TiO3
O ZirconZr(SiO4)
O Amphibole SupergroupAX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
O Epidote{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
O SideriteFeCO3
FFluorine
F Amphibole SupergroupAX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
AlAluminium
Al Amphibole SupergroupAX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
Al Epidote{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
SiSilicon
Si QuartzSiO2
Si ZirconZr(SiO4)
Si Amphibole SupergroupAX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
Si Epidote{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
SSulfur
S PyriteFeS2
ClChlorine
Cl Amphibole SupergroupAX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
CaCalcium
Ca Epidote{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
TiTitanium
Ti IlmeniteFe2+TiO3
Ti Amphibole SupergroupAX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
CrChromium
Cr ChromiteFe2+Cr23+O4
FeIron
Fe ChromiteFe2+Cr23+O4
Fe MagnetiteFe2+Fe23+O4
Fe IlmeniteFe2+TiO3
Fe PyriteFeS2
Fe Epidote{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Fe SideriteFeCO3
ZrZirconium
Zr ZirconZr(SiO4)
AuGold
Au GoldAu

References

Sort by

Year (asc) Year (desc) Author (A-Z) Author (Z-A)
Lindgren, Waldemar (1900), Description of the Colfax sheet, California: USGS Geological Atlas, Colfax folio (Folio No. 66), 10 pp.
Lindgren, Waldemar (1911), The Tertiary gravels of the Sierra Nevada of California: USGS Professional Paper 73, 226 pp.: 146-147.
MacBoyle, Errol (1919), Mines and mineral resources of Nevada County: California Journal of Mines and Geology, California Mining Bureau (Report 16): 16: 30-33.
Clark, Wm. B. (1970a) Gold districts of California: California Division Mines & Geology Bulletin 193: 87-88.
Yeend, W.E. (1974) Gold-bearing gravel of the ancestral Yuba River, Sierra Nevada, California. USGS Professional Paper 772, 44 pp.
Orris, G.J., and Bliss, J.D. (1985), Geologic and Grade-Volume Data on 330 Gold Placer Deposits: USGS Open-File Report 85-213, 172 pp.
Saucedo, G. J. and Wagner, D. L. (1992), Geologic map of the Chico Quadrangle, California: California Department of Conservation, Division of Mines and Geology Regional Geologic Map Series, Map No. 7A, scale 1:250,000.
USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10310640 & 60001026.

USGS MRDS Record:10310640

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