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Rio Grande Pit

Past Producer in Jefferson county in Colorado, United States with commodities Sand and Gravel, Construction, 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. Host and associated rocks
  9. Nearby scientific data
  10. Geologic structures
  11. Ore body information
  12. Economic information about the deposit and operations
  13. Mining district
  14. Land status
  15. Ownership information
  16. Links to other databases
  17. Bibliographic references
  18. General comments
  19. Reporter information

Geologic information

Identification information

Deposit ID 10087760
MRDS ID D009449
Record type Site
Current site name Rio Grande Pit

Geographic coordinates

Geographic coordinates: -105.17002, 39.76805 (WGS84)
Elevation 1679
Relative position 3 MILES N 81 E FROM GOLDEN

Site location context

Political divisions (FIPS codes)

Jefferson(county)

Colorado(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Golden(quadrangle 1:24,000 scale)

Denver West(quadrangle 1:100,000 scale)

Denver(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Clear(hydrologic unit)

South Platte(hydrologic accounting unit)

South Platte(hydrologic subregion)

Missouri(hydrologic region)

Geographic areas

Country State County
United States Colorado Jefferson

Public Land Survey System information

Meridian Township Range Section Fraction State
6th Principal 003S 070W 25 NE Colorado

Comments on the location information

  • ALONG CLEAR CREEK AT INDIANA ST. ; INFO FROM LAND.ST :(1975)

Commodities

Commodity Importance
Sand and Gravel, Construction Primary
Gold Secondary
Silver Secondary

Comments on the commodity information

  • PLACER GOLD WAS RECOVERED AS BY-PRODUCT OF WASHING/SCREENING OF SAND AND GRAVEL FOR CONSTRUCTION AGGREGATE

Materials information

Materials Type of material
Gold Ore
Sand and Gravel Ore

Analytical data

Result TEST DRILLING BY HUMPHREYS GOLD CORP. IN SECS. 24 AND 25 SHOWED AVERAGE AU SIZE OF 5.7 TO 10 COLORS/MG, BUT ONE HOLE RECOVERED A 16.98-MG NUGGET. TYPICAL SHIPMENT FROM RIO GRANDE PIT CONTAINED 850 FINE IN AU, 147 FINE IN AG, AND 3 FINE IN UNSPECIFIED BASE METALS. PARKER REFERS TO 1936 WRITTEN COMM. FROM KENNETH L. SCHUSSMAN WHO ANALYZED SAMPLES AND FOUND 0.04 COLORS/MG (2.2 WT %) ON PLUS 8 MESH, 0.09 COLORS/MG (4.0 WT %) ON MINUS 8/PLUS 14 MESH, 0.35 COLORS/MG (30.8 WT %) ON MINUS 14/PLUS 28 MESH, 1.8 COLORS/MG (29.4 WT %) ON MINUS 28/PLUS 48 MESH, 15.7 COLORS/MG (16.0 WT %) ON MINUS 48/PLUS 100 MESH, 63.3 COLORS/MG (4.3 WT %) ON MINUS 100/PLUS 170 MESH, 327 COLORS/MG (3.2 WT %) ON MINUS 170/PLUS 325 MESH, 5780 COLORS/MG (10.2 WT %) ON MINUS 325 MESH. ANOTHER 1936 WRITTEN COMM. (FROM K.C. FORCADE) CITES ANALYSIS OF TWO HEAVY MINERAL CONCENTRATES FROM TEST HOLES
Result SAMPLE 1 CONTAINED 79 % MAGNETITE, 6.5 % ZIRCON, 3.5 % MONAZITE, 3 % APATITE, 1.5 % GARNET, 6.5 % OTHER
Result SAMPLE 2 CONTAINED 70 % MAGNETITE, 9.5 % PYRITE, 7 % ZIRCON, 7 % MONAZITE, 2.5 % APATITE, 4 % OTHER.

Host and associated rocks

  • Host or associated Host
    Rock type Unconsolidated Deposit > Sand and Gravel
    Rock unit name Louviers Alluvium;Denver Formation
    Rock description Louviers Alluvium;Denver Formation
    Stratigraphic age (youngest) Pleistocene

Nearby scientific data

(1) Modern alluvium
ListMap

Economic information

Geologic structures

Type of structure Regional
Structure description Denver Basin, Front Range Uplift
Type of structure Local
Structure description Denver Basin

Ore body information

  • General form TABULAR
  • General form TABULAR

Economic information about the deposit and operations

Development status Past Producer
Commodity type Both
Significant No
Year of last production 1973

Mining district

District name Golden Area

Land status

Ownership category Private

Ownership information

  • Type Operator
    Owner Rio Grande Gravel Co.

Reference information

Bibliographic references

  • Deposit

    VAN HORN, RICHARD, 1972, SURFICIAL AND BEDROCK GEOLOGIC MAP OF THE GOLDEN QUADRANGLE, JEFFERSON COUNTY, COLORADO: USGS MAP I-761-A

  • Deposit

    PARKER, B.H., JR., 1974, GOLD PLACERS OF COLORADO: COLORADO SCHOOL OF MINES QUART., V. 69, NO. 3, P. 63-126

General comments

Subject category Comment text
Deposit AU WAS FOUND CONCENTRATED AT BOTTOM OF UPPER AND LOWER THIRDS OF GRAVEL DEPOSIT

Reporter information

Type Date Name Affiliation Comment
Reporter 01-AUG-1982 Schwochow, Stephen D. Colorado Geological Survey

Beyond USGS

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

Maps centered on this site

Authoritative Colorado resources

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