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Afterthought

Past Producer in Shasta county in California, United States with commodities Copper, Silver, Gold, Lead
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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. Ore body information
  13. Controls for ore emplacement
  14. Economic information about the deposit and operations
  15. Mining district
  16. Land status
  17. Production statistics
  18. Workings at the site
  19. Links to other databases
  20. Bibliographic references
  21. General comments
  22. Reporter information

Geologic information

Identification information

Deposit ID 10077520
MRDS ID W025215
Record type Site
Current site name Afterthought
Alternate or previous names Copper Hill

Geographic coordinates

Geographic coordinates: -122.08331, 40.73596 (WGS84)
Elevation 549
Relative position 24 MILES EAST OF REDDING, ADJACENT TO HWY 299

Site location context

Political divisions (FIPS codes)

Shasta(county)

California(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Oak Run(quadrangle 1:24,000 scale)

Redding(quadrangle 1:100,000 scale)

Redding(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Lower Sacramento(hydrologic accounting unit)

Sacramento(hydrologic subregion)

California(hydrologic region)

Federal lands

Bureau of Land Management(Bureau of Land Management CA)

Bureau of Land Management CA BLM(Type of land area)

BLM(Federal land areas administered by BLM)

Geographic areas

Country State County
United States California Shasta

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 033N 002W 10,11,15 California

Comments on the location information

  • Original coordinates for line#1 were: lat/long NAD27 40-44-10N 122-4-56W (40.73611 -122.08222); UTM N4509475 E578350 Z10N; PLSS line# 1: Meridian- Mount Diablo, TWNSHP 033N, RNG 002W, Sect 10,11,15, Sect_fract <blank>. The location was modified by view of workings in Google Earth, which is pretty close to coordinates given in Mosier and others (2009)

Commodities

Commodity Importance
Copper Primary
Silver Secondary
Gold Secondary
Lead Secondary

Materials information

Materials Type of material
Bornite Ore
Chalcocite Ore
Chalcopyrite Ore
Covellite Ore
Galena Ore
Limonite Ore
Malachite Ore
Pyrite Ore
Sphalerite Ore
Azurite Ore
Tennantite Ore
Tetrahedrite Ore
Luzonite Ore
Barite Gangue

Alteration

  • (Local) Silicified, Pyritized, Sericite, Carbonatization, Albitization

Analytical data

Result 15 % ZN, 2 % CU, 5 OZ. AG/TON, 2 % PB, AND .03 OZ AU/TON.

Mineral occurrence model information

Model code 184
USGS model code 28a
Deposit model name Massive sulfide, kuroko
Mark3 model number 93

Host and associated rocks

  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
    Rock unit name Bully Hill Rhyolite
    Rock description Bully Hill Rhyolite
    Stratigraphic age (youngest) Late Jurassic
    Stratigraphic age (youngest) Late Jurassic
    Stratigraphic age (youngest) Late Jurassic

Nearby scientific data

(1) -122.08331, 40.73596
ListMap

Economic information

Ore body information

  • General form LENTICULAR
    Strike NW
    Dip MODERATELY STEEP NE
    Length 121.92M

Controls for ore emplacement

  • Intersection Between Rhyolite - Metasedimentary Contact And A Series Of Steeply Dipping Strike Faults.

Comments on the geologic information

  • HOST ROCK IS PROBABLY A RHYOLITE PORPHYRY. ; GEOL.DESC: ALTERED ROCKS CONTAIN SIGNIFICANT QUANTITIES OF ALBITE, SILICA, HYDROUS MICA, CALCITE AND PYRITE. SULFIDE ORE BODIES REPLACE SHEARED HOST ROCKS AT CONTACT. 16 ORE BODIES COMPOSED OF MASSIVE AND BANDED SULFIDES.

Economic information about the deposit and operations

Operation type Underground
Development status Past Producer
Commodity type Metallic
Deposit size Large
Significant No
Discovery year 1862
Year of first production 1873
Year of last production 1952
Production years 1905 - 1952

Mining district

District name East Shasta Copper - Zinc

Land status

Ownership category National Forest

Production statistics

  • Year 1952
    Period 1905 - 1952
    Material CU
    Accuracy Accurate
    Description Cp_Grade: ^3.23 % Cu, 16.15 % Zn, 2.17 % Pb, 5.55 Oz/Ton Ag, .03 Oz/Ton Au.
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Gold Gold 1g/mt
    Silver Silver 157g/mt
    Lead Lead 2wt-pct
    Zinc Zinc 16wt-pct
    Copper Copper 3wt-pct

Workings at the site

  • Type of workings Underground
    Area 667.755HA
    Length 886.97M
    Overall depth 222.2M

Comments on the workings information

  • OVERALL LENGTH OF 17,200 FEET INCLUDES DRIFTS, CROSSCUTS AND STOPES IN ADDITION TO 2,200 FEET OF SHAFTS, RISES AND WINZES.

Reference information

Bibliographic references

General comments

Subject category Comment text
Deposit OUTCROPS ARE MARKED BY PROMINENT GOSSANS FIRST PROSPECTED FOR THEIR GOLD CONTENT.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-APR-1978 Tatkin, T.; Albers, John P. 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.