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Cumo Prospect

Prospect in Boise county in Idaho, United States with commodities Copper, Molybdenum, Silver, Tungsten, Rhenium, Lead, Zinc, Gallium
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Geologic information

Identification information

Deposit ID 10078685
MRDS ID W027150
MAS/MILS ID 0160150056
Record type Deposit
Current site name Cumo Prospect
Alternate or previous names Cumo Moly Deposit

Geographic coordinates

Geographic coordinates: -115.78426, 44.03598 (WGS84)
Elevation 1676
Relative position 35 MI NE BOISE, 14 miles north of IDAHO CITY
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Geographic areas

Country State County
United States Idaho Boise

Public Land Survey System information

Meridian Township Range Section Fraction State
Boise 008N 006E 07,08,17,18 Idaho

Comments on the location information

  • The Cumo prospect is 14 mi north of Idaho City, Idaho. The prospect is accessible by unimproved road up Grimes Creek northeast from Pioneerville. It is on the Grimes Pass topographic map, and in the Boise National Forest. The prospect is located on a steep, north-facing, forested slope between altitudes 5500 and 6500 ft, and chiefly between Copper and Cricket Creeks, both of which flow north into Grimes Creek.

Commodities

Commodity Importance
Copper Primary
Molybdenum Primary
Silver Secondary
Tungsten Secondary
Rhenium Tertiary
Lead Tertiary
Zinc Tertiary
Gallium Tertiary

Materials information

Materials Type of material
Chalcocite Ore
Chalcopyrite Ore
Covellite Ore
Galena Ore
Molybdenite Ore
Sphalerite Ore
Biotite Gangue
Calcite Gangue
Chlorite Gangue
Epidote Gangue
Plagioclase Gangue
Pyrite Gangue
Quartz Gangue

Alteration

  • (Local) SilicificationSilicification, Argillization, Propylitization, Potassic, Oxidation
  • (Local) Argillization
  • (Local) Propylitization
  • (Local) Potassic
  • (Local) Oxidation

Analytical data

Result 4 DACITE PORPHYRY SAMPLES GAVE 6 - 35 PPM MO, 54 - 360 PPM CU
Result 1 LAMPROPHYRE SAMPLE HAD 1 PPM MO, 420 PPM CU
Result 2 ANDESITE SAMPLES GAVE 2 - 3 PPM MO, 1200 - 1500 PPM CU

Comments on the analytical data

  • Description from Thor Kiilsgaard unpublished description. Re-assay of pulps from drill core for minor and trace elements indicates average elemental concentrations of 2.8 ppm Ag, 17.9 ppm Ga. In the Mo zone the average concentration of Re is 43 ppm (Mosquito Consolidated Gold Mines, Ltd., 2007).

Mineral occurrence model information

Model code 79
USGS model code 21a
Deposit model name Porphyry Cu-Mo
Mark3 model number 2
Model code 80
USGS model code 21b
Deposit model name Porphyry Mo, low-F

Host and associated rocks

  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Dacite
    Stratigraphic age (youngest) Early Permian
    Stratigraphic age (youngest) Early Permian
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Quartz Latite
    Rock unit name Idaho Batholith-Quartz Monzonite;Dikes-Biotite Quartz Latite Porphyry, Andesite, Dacite Porphyry, Lamprophyre;Dikes-Rhyolite, Diabase
    Rock description Idaho Batholith-Quartz Monzonite;Dikes-Biotite Quartz Latite Porphyry, Andesite, Dacite Porphyry, Lamprophyre;Dikes-Rhyolite, Diabase
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite
  • Host or associated Associated
    Rock type Plutonic Rock > Porphyry > Lamprophyre
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Dacite
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Quartz Latite
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite
  • Host or associated Host
    Rock type Plutonic Rock > Porphyry > Lamprophyre

Nearby scientific data

(1) -115.78426, 44.03598
ListMap

Geologic structures

Type of structure Local
Structural terms stockwork
Structure description Fractures, Shears And Faults, Breccia

Ore body information

  • General form tabular
    Area 520HA

Controls for ore emplacement

  • fractures: Fractures

Comments on the geologic information

  • The deposit is located and controlled by the strong, northeast-trending trans-Challis fault system, and, to a lesser extent, by the more or less parallel porphyritic rhyolite dikes that make up the associated porphyry belt.

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic
Deposit size Small
Significant Yes

Mining district

District name Grimes Pass District

Land status

Ownership category National Forest
Area name Boise National Forest

Ownership information

  • Type Owner-Operator
    Owner Mosquito Consolidated Gold Mines Ltd
    Interest 100
    Home office Vancouver BC
    Year 2010
  • Type Operator
    Owner Amax Exploration, Inc.
    First year 1974

Comments on the ownership information

  • The deposit was discovered by AMAX Exploration in 1963, and from 1968 to 1984 was continuously explored, including efforts by Curwood Mining Co., Midwest Oil Co., and AMAX/AMOCO (Baker, 1985). AMAX and partners drilled a geochemical anomaly - 1968-1982, Mosquito Resources had the property sometime later and apparently sold it to Kobex Resources around 2006 and then resumed control in Oct. 2006.

Reserves and resources

  • Type In-situ
    Name Resource
    Estimate year 2007
    Total resources 1,258,000,000mt ore
    Commodity Subtype Grade units Group Importance Year
    Molybdenum Mo 0.056 wt-pct Molybdenum Primary 2007
    Copper Cu 0.074 wt-pct Copper Secondary 2007
  • Type In-situ
    Estimate year 2009
    Inferred 2,250,000,000mt ore
    Indicated 1,360,000,000mt ore
    Remarks Resources are for the low cutoff grade of $5.00
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.0756 wt-pct Copper Primary 2009
    Molybdenum MoS2 0.074 wt-pct Molybdenum Primary 2009
    Silver Ag 2.26 g/mt Silver Secondary 2009
    Tungsten W 0.0045 wt-pct Tungsten Secondary 2009
  • Type In-situ
    Estimate year 2011
    Indicated 1,838,000,000mt ore
    Remarks 2011 NI 43-101 report, p. 125
    Commodity Subtype Grade units Group Importance Year
    Copper 0.08 wt-pct Copper Primary 2011
    Molybdenum 0.059 wt-pct Molybdenum Primary 2011
    Silver 2.38 g/mt Silver Secondary 2011
    Tungsten 39.06 g/mt Tungsten Secondary 2011
  • Type In-situ
    Estimate year 2011
    Inferred 3,580,000,000mt ore
    Remarks 2011 NI 43-101 report, p. 126.
    Commodity Subtype Grade units Group Importance Year
    Copper 0.07 wt-pct Copper Primary 2011
    Molybdenum 0.033 wt-pct Molybdenum Primary 2011
    Silver 2.11 g/mt Silver Secondary 2011
    Tungsten 11.51 g/mt Tungsten Secondary 2011

Comments on the reserve resource information

  • The Cumo deposit is estimated to contain 1,258,000,000 tons of mineralized material having an average grade of 0.059 percent MoS2, and 0.074 percent copper (Rostad, 1978). The deposit is not mineable under present economic conditions, however, it should be considered as a potential future resource of molybdenum.

Comments on the workings information

  • The altered granodiorite and the steep-dipping rhyolite dikes of the deposit presented drilling problems to the exploration program as the drill bit tended to deflect away from the hard, brittle rhyolite into the softer altered granodiorite. There has been no known exploration or development of the deposit since 1984.

Comments on development

  • CUMO PROSPECT FIRST MENTIONED 1970

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS W027150
Idaho Geological Survey Idaho Mines and Prospects IMP CH_542 http://www.idahogeology.org/
U.S. Bureau of Mines Minerals Availability System MAS 0160150056

Bibliographic references

  • Analytical Data

    Mosquito Consolidated Gold Mines, Ltd., 2007, Mosquito confirms historical assays at Cumo: on line at http://www.mosquitogold.com, 6/11/07.

  • Deposit

    WHITNEY, M. S., 1975 , GEOLOGY OF THE CUMO PROSPECT, BOISE COUNTY, IDAHO: GOLDEN, COLORADO, COLORADO SCHOOL OF MINES, M. S. THESIS, 84 P.

  • General

    Holmgren, J. A., 2008 , SUMMARY REPORT ON THE CUMO PROPERTY BOISE COUNTY, IDAHO, for Mosquito Consolidated Gold Mines: CUMO 2008 Technical Report

  • Geology

    Anderson, A.L., 1947, Geology and ore deposits of the Boise Basin, Idaho: U.S. Geological Survey Bulletin 944-C.

  • Reserve-Resource

    George Cross Newsletter, 1995, Report on CUMO drilling, February 16.

  • Deposit

    IDAHO DEPT. OF LABOR AND INDUSTRIAL SERVICES, 1975 , FIRST ANNUAL REPORT ADDENDUM, JULY 1 , 1974 - JUNE 30 , 1975 , 95 P.

  • Geology

    Baker, Donald J., 1985, Geology of the Cumo molybdenum-copper system, Boise County, Idaho: Geological Society of America Abstracts with Programs, 1985, V. 17, No. 4, p. 207.

  • Reserve-Resource

    Rostad, Ora, 1978, Discussion notes: Economic Geology, vol. 73, p. 1366-1367.

  • Deposit

    1971 GEOLMAP MIDWEST OIL CO., WHITNEY M. S. THESIS

  • Geology

    Kiilsgaard, T.H., and Lewis, R.S., 1985, Plutonic rocks of Cretaceous age and faults in the Atlanta lobe of the Idaho batholith, Challis quadrangle: U.S. Geological Survey Bulletin 1658, Chapter B.

  • Reserve-Resource

    MOSQUITO CONSOLIDATED GOLD MINES LIMITED, 2009, MOSQUITO FILES CUMO NI 43-101, ANNOUNCES 1.3 BILLION TONS INDICATED, 2.2 BILLION TONS INFERRED OF HIGHER-GRADE MULTI-ELEMENT MINERALIZATION: NI43-101 report filed by Mosquite Consolidated Gold Mines Limited with SEDAR [www.mosquitogold.com] accessed from http://www.infomine.com/index/pr/PA751752.PDF, July 14, 2009.

  • Deposit

    1974 GEOLMAP AMAX EXPLORATION, INC., WHITNEY M. S. THESIS

  • Geology

    Kiilsgaard, T.H., and Bennett, E.H., 1995, Tertiary molybdenum stockworks, in Geology and Mineral Resource Assessments of the Challis 1o x 2o Quadrangle, Idaho: U.S. Geological Survey Professional Paper 1525, p. 131-134.

  • Reserve-Resource

    Jones, Ivor, et al, 2011, Resource Estimate Update May 2011, NI 43-101 Technical Report prepared for Mosquito Consolidated Gold Mines Ltd. Cumo Project; submitted to sedar.com on June 15, 2011, 223 pages

  • Deposit

    1975 COMPILE IDAHO DEPT LABOR AND INDUSTRIAL SERVICES, ADDENDUM

  • Geology

    Baker, D.J., 1983, The CUMO Molybdenite System, Boise, Idaho, A Comprehensive Summary?,Climax Molybdenum Company, April 1983, unpublished.

  • Deposit

    SHANNON, S.S., JR., 1971, EVALUATION OF COPPER AND MOLYBDENUM GEOCHEMICAL ANOMALIES AT THE CUMO PROSPECT, BOISE COUNTY, IDAHO, IN BOYLE, R.W., AND MCGERRIGLE, J.I., EDS., GEOCHEMICAL EXPLORATION: CANADIAN INST. OF MINING AND METALL. SPEC. VOL. II, P. 247-250.

  • Geology

    Killsgaard, T.H, Fisher, F.S. and Bennet, E.H., 1989, Gold-Silver Deposits Associated with the Trans-Challis Fault System, Idaho; USGS Bull 1857-B, p. B22-B44

  • Deposit

    Worthington, J.e., 2007, Porphyry and other molybdenum deposits of Idaho and Montana: Idaho Geological Survey Technical Report 07-3, University of Idaho, Moscow, Idaho

General comments

Subject category Comment text
Deposit MOST VEINS ONLY 2 MM WIDE

Reporter information

Type Date Name Affiliation Comment
Reporter 01-JUL-1977 Siefken, Robert R. (Miller, Pat) U.S. Geological Survey
Updater 22-JUN-2009 Causey, J. Douglas U.S. Geological Survey
Reporter 01-JUL-2005 Kiilsgaard, Thor U.S. Geological Survey Actual date is approximate. Author has pass away.
Editor 07-JUL-2009 Bookstrom, A.A. U.S. Geological Survey