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  3. Mineral Resource Data System (MRDS)

Mount Hurst

Occurrence in Alaska, United States with commodity Chromium
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Commodities
  6. Materials information
  7. Mineral occurrence model information
  8. Nearby scientific data
  9. Economic information about the deposit and operations
  10. Mining district
  11. Links to other databases
  12. Bibliographic references
  13. General comments
  14. Reporter information

Geologic information

Identification information

Deposit ID 10308979
MRDS ID A015019
Record type Site
Current site name Mount Hurst
Related records 10137165, 10002582

Geographic coordinates

Geographic coordinates: -156.93729, 63.23193 (WGS84)
Relative position Mt. Hurst is a 2882-foot-high peak approximately 25 miles northwest of Ophir. The site corresponds to location 10 of Roberts (1984), in section 15, T. 26 S., R. 10 E, Kateel River Meridian. It is on a northeast-trending ridge, approximately 1 mile northeast of the summit of Mt. Hurst. The location is accurate within 1/2 mile.

Site location context

Political divisions (FIPS codes)

Yukon-Koyukuk(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Ophir A-2(quadrangle 1:63,360 scale)

Ophir SE(quadrangle 1:100,000 scale)

Ophir(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Alaska(hydrologic region)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Chromium Critical Primary

Materials information

Materials Type of material
Chromite Ore
Spinel Ore

Mineral occurrence model information

Model code 15
USGS model code 8a
Deposit model name Podiform chromite (minor)
Mark3 model number none

Nearby scientific data

(1) -156.93729, 63.23193
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = Mt. Hurst is composed of chromite- and chrome spinel-bearing ultramafic rocks surrounded by lower Paleozoic crystalline limestone, schist, slate, phyllite, quartz, and chert. A nearby upper Paleozoic sequence of greenstone, metavolcanic rocks, tuff, and chert-bearing sedimentary rocks suggests a possible ophiolitic origin for the ultramafic rocks (Roberts, 1984). The ultramafic rocks at Mt. Hurst are crudely layered; certain layered zones are traceable for more than 2 miles. Rock types include dunite, wehrlite, harzburgite, lherzolite, and clinopyroxenite. One outcrop of dunite has been altered to carbonate, quartz, and talc. At least two minor occurrences of basalt and one outcrop of gabbro are also present (Roberts, 1984). Chromitite samples collected from the Mt. Hurst area are anomalous in platinum (0.014 - 0.026 ounce per ton) and palladium (0.003 ounce per ton). Wehrlite samples also contained minor amounts of platinum. Altered dunite samples contained elevated concentrations of mercury, antimony, arsenic, and silver. Coalescent or banded chromite is present almost exclusively within dunite layers in wehrlite (Roberts, 1984). Heavy-mineral concentrates panned from three separate drainages on the flanks of Mt. Hurst respectively contained 1474 ppb platinum, 1508 ppb platinum, and 2674 ppb gold (Roberts, 1984). The largest chrome spinel occurrence in the Mt. Hurst area is at this site (Roberts, 1984, locality 10). It is in a chromite band in a light orange-brown dunite lens in well-layered, light-green wehrlite. The chromite band trends northeast for about 30 feet; the southern end disappears beneath vegetation, soil and talus. It pinches and swells from 6 to 30 inches thick over 30 feet. Concentrations of chrome spinel within the chromite band vary from 30 to 80% of the rock. Chromitite samples from this locality contain about 30% chromic oxide (Roberts, 1984). The chrome spinel occurrences on Mt. Hurst appear to be very sparse and variable in size and quality. The presence of detectable platinum and palladium in sediments shed from the ultramafic rocks at Mt. Hurst (see Boob Creek, OP013) suggests a potential for paleo-placers (Roberts, 1984).

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Mining district

District name Ophir

Comments on the workings information

  • Workings / Exploration = The U.S. Bureau of Mines first investigated Mt. Hurst as a potential source of chromic oxide and platinum-group metals in 1981. Since then, there have been staking and minor exploration programs by private interests.

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Roberts, 1984

General comments

Subject category Comment text
Deposit Model Name = Podiform chromite (Cox and Singer, 1986; model 8a)
Deposit Other Comments = See also Boob Creek (OP013).

Reporter information

Type Date Name Affiliation Comment
Reporter 07-AUG-01 Cameron, C.E. Northern Associates Inc.

Beyond USGS

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

Maps centered on this site

Authoritative Alaska resources

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