Ursus

The Ursus is a lead and silver 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: Ursus

Commodity

Primary: Lead
Primary: Silver
Secondary: Arsenic
Secondary: Copper

Location

State: Alaska
District: McGrath

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

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

Physiography

Not available

Mineral Deposit Model

Model Name: Polymetallic veins

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: Ankerite in quartz porphyry.

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Pyrite
Ore: Galena
Gangue: Tourmaline
Gangue: Quartz

Comments

Comment (Reference): Primary Reference = DiMarchi and others, 1997

Comment (Deposit): Other Comments = See Mystery Mountains West (MD029) prospect. The Ursus Prospect is on land selected or owned by Doyon Ltd. For additional information contact Doyon Ltd. at 210 1st Ave., Fairbanks, Alaska, 99701.

Comment (Workings): Workings / Exploration = Ursus is one of a number of prospects explored by the mineral industry from 1975 to 1997 as a large porphyry copper-gold system centered on the Mystery Mountains (Andrews, 1978; Bell, 1983; DiMarchi and others, 1997). Limonitically stained grab samples of quartz-tourmaline veins yielded up to 2.30 percent lead, 4.7 ounces/ton (161 grams/tonne ) silver, and 1,000 ppm copper (DiMarchi and others, 1997).

Comment (Geology): Age = the Ursus prospect is inferred to be Late Cretaceous, based on isotopic ages of plutonic rocks in Mystery Mountains (Moll and others, 1981).

Comment (Exploration): Status = Inactive

Comment (Geology): Geologic Description = The Ursus prospect occurs in both tourmaline bearing, pyrite, feldspar porphyry and brown brecciated hornfels. Vein breccias are common in the hornfels. The diffuse mineral zone is marked by strong limonite gossan development and conspicuous ankeritic alteration in the quartz porphyry intrusion. The Ursus prospect is inferred to be Late Cretaceous, based on isotopic ages of plutonic rocks in Mystery Mountains (Patton and others, 1980; Moll and others, 1981) . Ursus is thought to represent an outer mineral zonation away from the central Mystery Mountains and is characterized by anomalous lead, silver and zinc in soils. An inner copper-gold zonation in the central Mystery Mountains is manifested by the Frozen Creek (MD032), Copenhagen (MD030) and Pork Chop (MD0031) copper-gold prospects. Limonitically stained grab samples of quartz-tourmaline veins yielded up to 2.30 percent lead, 1,000 ppm copper, and 4.70 ounces/ton silver (DiMarchi and others, 1997).

Comment (Deposit): Model Name = Polymetallic vein (Cox and Singer, 1986; model no. 22c)

References

Reference (Deposit): Bell, J.D., 1983, Mystery Mountains Area, Block 10, Doyon Region, Kuskokwim District: Hecla Mining Company Summary Report, 25 pages.

Reference (Deposit): Andrews, Tom, 1978, Summary of Progress, Doyon Project, Mystery Mountains, (Block 10): Anchorage, Alaska, WGM Inc., 24 pages (Held by Doyon Ltd., as proprietary report 78-42).

Reference (Deposit): Moll, E.J., Silberman, M.L., and Patton, W.W. Jr., 1981, Chemistry, mineralogy, and K-Ar ages of igneous and metamorphic rocks of the Medfra quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-811C, 15 p., 2 sheets, scale 1:250,000.

Reference (Deposit): DiMarchi, J.J., and Frantz, P.S., 1997, Annual Report for 1997-Doyon Option Lands, Block 10: ASA Inc.-Montague Gold Joint Venture Report, Volume II: Unpublished report, 189 p. (Report held by Doyon, Limited, Fairbanks, Alaska.)

Reference (Deposit): Patton, W.W., Jr., Moll, E.J., Dutro, J.T., Jr., Silberman, M.L., and Chapman, R.M., 1980, Preliminary geologic map of Medfra quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-811-A, 1 sheet, scale l:250,000.

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