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Sierra Iron Mine

Past Producer in Sierra county in California, United States with commodity Iron
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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. Host and associated rocks
  10. Nearby scientific data
  11. Geologic structures
  12. Ore body information
  13. Economic information about the deposit and operations
  14. Land status
  15. Reserves and resources
  16. Links to other databases
  17. Bibliographic references
  18. General comments
  19. Reporter information

Geologic information

Identification information

Deposit ID 10098348
MRDS ID M024297
Record type Site
Current site name Sierra Iron Mine
Alternate or previous names Lake Hawley and Spencer Lake Deposit
Related records 10262641

Geographic coordinates

Geographic coordinates: -120.7152, 39.69766 (WGS84)
Relative position NEAR DIVIDE BETWEEN NORTH FORK YUBA RIVER AND THE MIDDLE FORK OF THE FEATHER RIVER

Site location context

Political divisions (FIPS codes)

Sierra(county)

California(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Gold Lake(quadrangle 1:24,000 scale)

Portola(quadrangle 1:100,000 scale)

Chico(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Upper Yuba(hydrologic unit)

Lower Sacramento(hydrologic accounting unit)

Sacramento(hydrologic subregion)

California(hydrologic region)

Federal lands

Tahoe National Forest(National Forest)

National Forest FS(Type of land area)

FS(Federal land areas administered by FS)

Geographic areas

Country State County
United States California Sierra

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 021N 011E 14,11 California

Commodities

Commodity Importance
Iron Primary

Materials information

Materials Type of material
Magnetite Ore
Calcite Gangue
Talc Gangue

Alteration

  • (Local) Dynamothermally Metamorphosed

Analytical data

Result AVERAGE FIGURES OBTAINED THROUGH CALCULATIONS ON 7 SAMPLES FROM LAKE HAWLEY AND 1 SAMPLE FROM SPENCER LAKE SUGGESTS THE GRADE OF ORE TO BE ABOUT 21% FE.

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Granitoid > Quartz Monzonite
    Stratigraphic age (youngest) Pennsylvanian

Nearby scientific data

(1) -120.7152, 39.69766
ListMap

Economic information

Geologic structures

Type of structure Local
Structure description Folds And Faults

Ore body information

  • General form IRREGULAR TO LENTICULAR

Comments on the geologic information

  • THE METAMORPHIC ROCKS IN THE AREA BELONG TO THE CALAVERAS FORMATION. MOST OF THE CALAVERAS FORMATION IN THE VICINITY OF THE IRON-ORE DEPOSITS ARE OF LOW-GRADE METAMORPHIC ROCKS DERIVED FROM FINE SANDY SEDIMENTS, FROM TUFF AND TUFF BRECCIAS (RHYOLITE TO DACITE), FROM MIXTURES OF CALCAREOUS AND CLASTIC SEDIMENTS AND FROM CHERTS. A FEW THIN BEDS OF METAMORPHOSED CONGLOMERATE AND OF METAMORPHOSED VOLCANIC BRECCIA ARE PRESENT.

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic
Deposit size Small
Significant No

Land status

Ownership category National Forest

Reserves and resources

  • Type In-situ
    Estimate year 1948
    Total resources 36000mt ore
    Commodity Subtype Grade units Group Importance Year
    Iron Fe 21 wt-pct Iron Major 1948

Comments on the reserve resource information

  • DETAIL INFORMATION ON AVAILABLE MAGNETITE FROM THE TWO GROUPS ARE IN DURRELL AND PROCTOR, 1948.

Comments on the workings information

  • NO INFORMATION AVAILABLE

Reference information

Bibliographic references

  • Deposit

    DURRELL, C. AND PROCTOR, P.D., 1948; IRON-ORE DEPOSITS NEAR LAKE HAWLEY AND SPENCER LAKES, SIERRA COUNTY, CALIFORNIA, CA. DIV. OF MINES BULL. 129, P. 167-192

  • Reserve-Resource

    DURRELL AND PROCTOR, 1948

General comments

Subject category Comment text
Deposit TWO GROUPS OF DEPOSITS ABOUT A MILE AND A QUARTER APART, ONE CONSISTING OF 13 SMALL DEPOSITS NEAR LAKE SPENCER AND A LARGER ONE, 1 MILE SE OF LAKE HAWLEY. A MORE DETAIL DESCRIPTION OF EACH DEPOSIT IS FOUND IN THE REPORT BY DURRELL AND PROCTOR, 1948. ; INFO.SRC : 1 PUB LIT
Deposit THE MAGNETITE ORE DEPOSITS ARE OF TWO TYPES, DEPENDING UPON THE ROCK IN WHICH THEY WERE FORMED. LAKE HAWLEY GROUP AND MOST OF THE SPENCER LAKE GROUP CONSISTS ESSENTIALLY OF TALC AND MAGNETITE. THE SECOND TYPE CONSISTS OF MAGNETITE AND CALCITE. THE TWO GROUPS CONTAIN BOTH TYPES IN COMBINATION.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-MAY-1981 Fraticelli, L. A. (Albers, J.) U.S. Geological Survey

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Maps centered on this site

Authoritative California resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.