Quartz Hill

The Quartz Hill is a molybdenum mine located in Alaska.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

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Site Name

Primary: Quartz Hill

Commodity

Primary: Molybdenum

Location

State: Alaska
District: Ketchikan

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Prospect
Operation Type: Unknown
Years of Production:
Organization:
Significant:

Physiography

Not available

Mineral Deposit Model

Model Name: Porphyry Mo, low-F

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: Pyritization, silicification.

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Molybdenite
Ore: Pyrite
Gangue: Quartz

Comments

Comment (Exploration): Status = Active

Comment (Workings): Workings / Exploration = The Quartz Hill deposit was discovered in 1974. Since then, the orebody has been defined by more than 450 drill holes totalling about 265,000 feet (Maas and others, 1995, p. 265). Two test adits, totalling nearly 5,000 feet of underground workings, were driven in 1981 to better define the deposit and to collect metallurgical test samples.

Comment (Reserve-Resource): Reserves = the orebody is generally tabular and subhorizontal. Assuming a cutoff grade of 0.05% molybdenum sulfide (MoS2), the orebody has a surface area of about 5,000 feet by 10,000 feet, and extends to a depth of up to 1,700 feet. Resource estimates vary, depending on cutoff grades. In 1992, the property owners reported a 'probable resource' of 210 million metric tons (mt) averaging 0.22% MoS2, and an additional 'possible resource' of 1.2 billion mt averaging 0.12% MoS2. A more widely publicized estimate is a probable resource of 444 million mt containing 0.219% MoS2, and a possible resource of 1.36 billion mt averaging 0.136% MoS2 (Maas and others, 1995, p. 265).

Comment (Geology): Age = Miocene or Oligocene.

Comment (Reference): Primary Reference = Maas and others, 1995

Comment (Deposit): Other Comments = This world-class deposit is estimated to contain 10% of the free world's known reserves of molybdenum.

Comment (Geology): Geologic Description = The country rocks in the general area of the Quartz Hill deposit include: Cretaceous or Tertiary quartz diorite, granodiorite, and quartz monzonite of the Coast Range batholith; hypabyssal stocks and associated dikes of Miocene or Oligocene granite and gabbro; Tertiary lamprophyre dikes that postdate the stocks; and Tertiary and Quaternary basalt and andesite lava flows and cinder cones (Berg and others, 1988).? the Quartz Hill deposit consists of a molybdenite-quartz stockwork and molybdenite fracture coatings in a hypabyssal, Miocene or Oligocene, composite stock and associated apophyses of porphyritic, aplitic, and aphanitic quartz monzonite and quartz latite (Elliott and others, 1976; Hudson and others, 1977, 1978, 1979). Molybdenite-quartz veinlets and fracture coatings also occur in the country rocks near the stock. Pyrite is common, chiefly as disseminated grains and small veinlets in the porphyritic rocks, and in the country rocks near the stock.? the Quartz Hill deposit was discovered in 1974. Since then, the orebody has been defined by more than 450 drill holes totalling about 265,000 feet (Maas and others, 1995, p. 265). Two test adits, totalling nearly 5,000 feet of underground workings, were driven in 1981 to better define the deposit and to collect metallurgical test samples. The orebody is generally tabular and subhorizontal. Assuming a cutoff grade of 0.05% molybdenum sulfide (MoS2), the orebody has a surface area of about 5,000 feet by 10,000 feet, and extends to a depth of up to 1,700 feet. Resource estimates vary, depending on cutoff grades. In 1992, the property owners reported a 'probable resource' of 210 million metric tons (mt) averaging 0.22% MoS2, and an additional 'possible resource' of 1.2 billion mt averaging 0.12% MoS2. A more widely publicized estimate is a probable resource of 444 million mt containing 0.219% MoS2, and a possible resource of 1.36 billion mt averaging 0.136% MoS2 (Maas and others, 1995, p. 265).

Comment (Deposit): Model Name = Porphyry Mo, Low-F (Cox and Singer, 1986; model 21b)

References

Reference (Deposit): Elliott, R.L., Smith, J.G., and Hudson, Travis, 1976, Upper Tertiary high-level plutons of the Smeaton Bay area, southeastern Alaska: U.S. Geological Survey Open-file Report 76-507, 16 p.

Reference (Deposit): Elliott, R.L., Berg, H.C., and Karl, Susan, 1978, map and table describing metalliferous and selected nonmetalliferous mineral deposits, Ketchikan and Prince Rupert quadrangles, Alaska: U.S. Geological Survey Open-file Report, 78-73-B,17 p., scale 1:250,000.

Reference (Deposit): Hudson, T.L., Miller, M. L., and Pickthorn, W. J., 1977, Map showing metalliferous and selected nonmetalliferous mineral deposits, Seward Peninsula, Alaska: U.S. Geological Survey Open-File Report 77-796-B, 46 p., one sheet, scale 1:1,000,000.

Reference (Deposit): Hudson, T.L., Elliott, R.L., and Smith, J.G., 1978, Chemistry of Quartz Hill intrusive rocks, Ketchikan quadrangle, in Johnson, K.M., ed., The United States Geological Survey in Alaska: accomplishments during 1977: U.S. Geological Survey Circular 772-B, p. B83-B85.

Reference (Deposit): Hudson, T.L., Smith, J.G., and Elliott, R.L., 1979, Petrology, chemistry, and age of intrusive rocks associated with the Quartz Hill molybdenite deposit, southeastern Alaska: Canadian Journal of Earth Sciences, v. 16, p. 1805-1822.

Reference (Deposit): Berg, H.C., Elliott, R.L., and Koch, R.D., 1988, Geologic map of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Mineral Investigations Series Map MF-1807,27 p., scale 1:250,000.

Reference (Deposit): Maas, K.M., Bittenbender, P E., and Still, J.C., 1995, Mineral investigations in the Ketchikan mining district, southeastern Alaska: U.S. Bureau of Mines Open-File Report 11-95, 606 p.

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