Iron Hill, Iron Hill carbonatite stock deposit

Deposit with commodities niobium, rare-earth elements, thorium, uranium

More information at and near this site: Nb-CO00019

About this location

Feature ID Nb-Mo00853
Geographic coordinates -107.071, 38.2599
Point definition Approximate center of the merged polygons
Polygon definition Approximate extent of the carbonatite unit from the geologic maps - Olson (1974) (2) and Hedlund and Olson (1975)
Reference Hedlund and Olson (1975); Map GQ-1178
Date: 1975; Scale: Medium (1:24,000-1:250,000)
Remarks (1) Staatz and others (1979); (2) Olson (1974)

Geologic information

Commodities niobium; rare-earth elements; thorium; uranium
Valuable materials chalcopyrite; columbite; galena; monazite; pyrochlore; sphalerite; thorite; thorogummite; xenotime
Associated materials aegirite; alkali feldspar; ankerite; ankeritic dolomite; apatite; barite; biotite; calcite; carbonate minerals (2); chalcedonic jasper; diopside; dolomite; fluorapatite; fluorite; garnet; goethite; hematite; idocrase; ilmenite; magnetite; manganese oxide; melilite; orthoclase; phlogopite; pyrite; pyrolusite (2); quartz; rutile (1); siderite; sodic amphiboles; zeolite; zircon (1)
Mineralization style dikes; veins
Age of mineralization 570 Ma (1)
Host rock age Cambrian or Neoproterozoic (2)
Host unit name Carbonatite (3)
Host lithologies ankeritic dolomite (2); carbonatite; dolomite (2)
Alteration biotite (2); carbonate minerals (2); phlogopite (2)
Reference Van Gosen, B.S., and Lowers, H.A., 2007, Iron Hill (Powderhorn) carbonatite complex, Gunnison County, CO—A potential source of several uncommon mineral resources: Mining Engineering, v. 59, no. 10, [October 2007], p. 56–62.
Additional references (1) Staatz and others (1979); (2) Olson and Hedlund (1981); (3) Hedlund and Olson (1975)

Descriptions from sources

Resources

“Iron Hill is made up entirely of the massive carbonatite […] The carbonatite exposed on this hill would all be in the category of reserves. Probable potential resources would lie below Iron Hill and could be extended to a depth of another 800 ft. The area underlain by carbonatite is 38,070,000 ft2.”

Staatz, M.H., Armbrustmacher, T.J., Olson, J.C., Brownfield, I.K., Brock, M.R., Lemons, J.F., Jr., Coppa, L.V., and Clingan, B.V., 1979, Principal thorium resources in the United States: U.S. Geological Survey Circular 805, 42 p.

Deposit models and geoenvironmental models

Type Model Reference
Deposit model Carbonatite-hosted REE deposits Verplanck, P.L., Van Gosen, B.S., Seal, R.R, and McCafferty, A.E., 2014, A deposit model for carbonatite and peralkaline intrusion-related rare earth element deposits: U.S. Geological Survey Scientific Investigations Report 2010–5070-J, 58 p., http://dx.doi.org/10.3133/sir20105070J.
Geoenvironmental model Carbonatite deposits Modreski, P.J., Armbrustmacher, T.J., and Hoover, D.B., 1995, Carbonatite deposits, in du Bray, E.A., eds., Preliminary compilation of descriptive geoenvironmental mineral deposit models: U.S. Geological Survey Open-File Report 95-831, p. 47–49, https://doi.org/10.3133/ofr95831.

Resource estimate summaries

Date Description Class Type Material Contained Units
1979 Reserves Unclassified ore thorium oxide (ThO2) 31,080 tons
1979 Resources Probable Potential ore niobium oxide (Nb2O5) 1,523,000 tons
1979 Resources Probable Potential ore thorium oxide (ThO2) 114,900 tons
1979 Resources Probable Potential ore uranium oxide (U3O8) 33,930 tons
1979 Reserves Unclassified ore niobium oxide (Nb2O5) 411,900 tons
1979 Reserves Unclassified ore uranium oxide (U3O8) 9,180 tons
1979 Reserves Unclassified ore total rare-earth oxide (TREO) 2,865,000 tons
1979 Resources Probable Potential ore total rare-earth oxide (TREO) 10,590,000 tons

Detailed resource estimates

1979: Reserves, Unclassified
Year of estimate 1979
Resource description Reserves
Resource classification Unclassified
Material thorium oxide (ThO2)
Material type ore
Material amount 722,700,000(includes amounts of more than one commodity)
Amount units tons
Grade 0.004
Grade units percent
Contained commodity 31,080
Contained commodity units tons
Material amount SI 655,600,000(calculated)(includes amounts of more than one commodity)
Material amount SI units metric tons
Grade SI 0.004(calculated)
Grade SI units percent
Contained commodity SI 24,780(calculated)
Contained commodity SI units metric tons
Contained commodity element Th
Short reference Staatz and others (1979)Page 30
Reference Staatz, M.H., Armbrustmacher, T.J., Olson, J.C., Brownfield, I.K., Brock, M.R., Lemons, J.F., Jr., Coppa, L.V., and Clingan, B.V., 1979, Principal thorium resources in the United States: U.S. Geological Survey Circular 805, 42 p.
1979: Resources, Probable Potential
Year of estimate 1979
Resource description Resources
Resource classification Probable Potential
Material niobium oxide (Nb2O5)
Material type ore
Material amount 2,672,000,000(includes amounts of more than one commodity)
Amount units tons
Grade 0.057(calculated)
Grade units percent
Contained commodity 1,523,000
Contained commodity units tons
Material amount SI 2,424,000,000(includes amounts of more than one commodity)
Material amount SI units metric tons
Grade SI 0.04(calculated)
Grade SI units percent
Contained commodity SI 965,800(calculated)
Contained commodity SI units metric tons
Contained commodity element Nb
Remarks Grade reported as average grade from analytical data of 28 samples
Short reference Staatz and others (1979)Page 31
Reference Staatz, M.H., Armbrustmacher, T.J., Olson, J.C., Brownfield, I.K., Brock, M.R., Lemons, J.F., Jr., Coppa, L.V., and Clingan, B.V., 1979, Principal thorium resources in the United States: U.S. Geological Survey Circular 805, 42 p.
1979: Resources, Probable Potential
Year of estimate 1979
Resource description Resources
Resource classification Probable Potential
Material thorium oxide (ThO2)
Material type ore
Material amount 2,672,000,000(includes amounts of more than one commodity)
Amount units tons
Grade 0.004
Grade units percent
Contained commodity 114,900
Contained commodity units tons
Material amount SI 2,424,000,000(includes amounts of more than one commodity)
Material amount SI units metric tons
Grade SI 0.004
Grade SI units percent
Contained commodity SI 91,600(calculated)
Contained commodity SI units metric tons
Contained commodity element Th
Remarks Grade reported as average grade of measurements from 151 stations
Short reference Staatz and others (1979)Page 31
Reference Staatz, M.H., Armbrustmacher, T.J., Olson, J.C., Brownfield, I.K., Brock, M.R., Lemons, J.F., Jr., Coppa, L.V., and Clingan, B.V., 1979, Principal thorium resources in the United States: U.S. Geological Survey Circular 805, 42 p.
1979: Resources, Probable Potential
Year of estimate 1979
Resource description Resources
Resource classification Probable Potential
Material uranium oxide (U3O8)
Material type ore
Material amount 2,672,000,000(includes amounts of more than one commodity)
Amount units tons
Grade 0.001
Grade units percent
Contained commodity 33,930
Contained commodity units tons
Material amount SI 2,424,000,000(includes amounts of more than one commodity)
Material amount SI units metric tons
Grade SI 0.001
Grade SI units percent
Contained commodity SI 26,100(calculated)
Contained commodity SI units metric tons
Contained commodity element U
Short reference Staatz and others (1979)Page 31
Reference Staatz, M.H., Armbrustmacher, T.J., Olson, J.C., Brownfield, I.K., Brock, M.R., Lemons, J.F., Jr., Coppa, L.V., and Clingan, B.V., 1979, Principal thorium resources in the United States: U.S. Geological Survey Circular 805, 42 p.
1979: Reserves, Unclassified
Year of estimate 1979
Resource description Reserves
Resource classification Unclassified
Material niobium oxide (Nb2O5)
Material type ore
Material amount 722,700,000(includes amounts of more than one commodity)
Amount units tons
Grade 0.057
Grade units percent
Contained commodity 411,900
Contained commodity units tons
Material amount SI 655,600,000(calculated)(includes amounts of more than one commodity)
Material amount SI units metric tons
Grade SI 0.04(calculated)
Grade SI units percent
Contained commodity SI 261,200(calculated)
Contained commodity SI units metric tons
Contained commodity element Nb
Short reference Staatz and others (1979)Page 30
Reference Staatz, M.H., Armbrustmacher, T.J., Olson, J.C., Brownfield, I.K., Brock, M.R., Lemons, J.F., Jr., Coppa, L.V., and Clingan, B.V., 1979, Principal thorium resources in the United States: U.S. Geological Survey Circular 805, 42 p.
1979: Reserves, Unclassified
Year of estimate 1979
Resource description Reserves
Resource classification Unclassified
Material uranium oxide (U3O8)
Material type ore
Material amount 722,700,000(includes amounts of more than one commodity)
Amount units tons
Grade 0.001
Grade units percent
Contained commodity 9,180
Contained commodity units tons
Material amount SI 655,600,000(calculated)(includes amounts of more than one commodity)
Material amount SI units metric tons
Grade SI 0.001(calculated)
Grade SI units percent
Contained commodity SI 7,060(calculated)
Contained commodity SI units metric tons
Contained commodity element U
Remarks Grade reported as average grade from analytical data of 28 samples
Short reference Staatz and others (1979)Page 30
Reference Staatz, M.H., Armbrustmacher, T.J., Olson, J.C., Brownfield, I.K., Brock, M.R., Lemons, J.F., Jr., Coppa, L.V., and Clingan, B.V., 1979, Principal thorium resources in the United States: U.S. Geological Survey Circular 805, 42 p.
1979: Reserves, Unclassified
Year of estimate 1979
Resource description Reserves
Resource classification Unclassified
Material total rare-earth oxide (TREO)
Material type ore
Material amount 722,700,000(includes amounts of more than one commodity)
Amount units tons
Grade 0.397
Grade units percent
Contained commodity 2,865,000
Contained commodity units tons
Material amount SI 655,600,000(calculated)(includes amounts of more than one commodity)
Material amount SI units metric tons
Grade SI 0.397
Grade SI units percent
Contained commodity SI 2,599,000(calculated)
Contained commodity SI units metric tons
Contained commodity element TREO
Short reference Staatz and others (1979)Page 30
Reference Staatz, M.H., Armbrustmacher, T.J., Olson, J.C., Brownfield, I.K., Brock, M.R., Lemons, J.F., Jr., Coppa, L.V., and Clingan, B.V., 1979, Principal thorium resources in the United States: U.S. Geological Survey Circular 805, 42 p.
1979: Resources, Probable Potential
Year of estimate 1979
Resource description Resources
Resource classification Probable Potential
Material total rare-earth oxide (TREO)
Material type ore
Material amount 2,672,000,000(includes amounts of more than one commodity)
Amount units tons
Grade 0.396(calculated)
Grade units percent
Contained commodity 10,590,000
Contained commodity units tons
Material amount SI 2.424(calculated)(includes amounts of more than one commodity)
Material amount SI units metric tons
Grade SI 0.396(calculated)
Grade SI units percent
Contained commodity SI 9,607,000(calculated)
Contained commodity SI units metric tons
Contained commodity element TREO
Remarks Grade reported as average grade from analytical data of 28 samples
Short reference Staatz and others (1979)Page 31
Reference Staatz, M.H., Armbrustmacher, T.J., Olson, J.C., Brownfield, I.K., Brock, M.R., Lemons, J.F., Jr., Coppa, L.V., and Clingan, B.V., 1979, Principal thorium resources in the United States: U.S. Geological Survey Circular 805, 42 p.

History of the site

Dates Status Detail Reference
1957 to 1965 Exploration Exploration activities by Du Pont included extensive exploratory drilling for niobium and an exploratory adit Van Gosen and Lowers (2007)

Geographic context based on the point coordinates