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Milan Mine

Past Producer in Coos county in New Hampshire, United States with commodities Copper, Lead, Zinc, Gold, Silver
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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. Alteration
  8. Mineral occurrence model information
  9. Host and associated rocks
  10. Nearby scientific data
  11. Geologic structures
  12. Economic information about the deposit and operations
  13. Production statistics
  14. Links to other databases
  15. Bibliographic references
  16. General comments
  17. Reporter information

Geologic information

Identification information

Deposit ID 10106478
MRDS ID W102017
Record type Site
Current site name Milan Mine

Geographic coordinates

Geographic coordinates: -71.25361, 44.56523 (WGS84)
Location accuracy 10000(meters)

Site location context

Political divisions (FIPS codes)

Coos(county)

New Hampshire(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

West Milan(quadrangle 1:24,000 scale)

Groveton(quadrangle 1:100,000 scale)

Lewiston(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Headwaters Connecticut River(hydrologic unit)

Upper Connecticut(hydrologic accounting unit)

Connecticut(hydrologic subregion)

New England(hydrologic region)

Geographic areas

Country State County
United States New Hampshire Coos

Comments on the location information

  • location from Gair and Slack, 1979.

Commodities

Commodity Importance
Copper Primary
Lead Secondary
Zinc Critical Secondary
Gold Tertiary
Silver Tertiary

Comments on the commodity information

  • The ore lenses at Milan were mined for their pyrite content and Cu, Pb, Zn, Ag, and Au were considered by-products. Hand-cobbed shipping ore reportedly contained 2.25%Cu, 7.26% Zn, 1.57% Pb, 1.5 oz/ton (51.4g/t) Ag and 0.21 oz/t (7.2 g/t) Au (Emmons, 1910).

Materials information

Materials Type of material
Chalcopyrite Ore
Galena Ore
Sphalerite Ore
Pyrite Ore
Bornite Ore
Chalcocite Ore
Albite Gangue
Biotite Gangue
Microcline Gangue
Muscovite Gangue
Quartz Gangue

Alteration

  • (Local) Hydrothermal Alteration

Mineral occurrence model information

Model code 184
USGS model code 28a
Deposit model name Massive sulfide, kuroko
Mark3 model number 93

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Metavolcanic Rock > Mafic Metamorphic Rock
    Rock unit name Ammonoosuc Volcanics
    Rock description Ammonoosuc Volcanics
    Stratigraphic age (youngest) Middle Ordovician

Nearby scientific data

(1) -71.25361, 44.56523
ListMap

Economic information

Geologic structures

Type of structure Local
Structure description Cross-fractures

Comments on the geologic information

  • The Milan mine is found is found near the lower contact of the upper member of the Ammonoosuc Volcanics, a metavolcanic unit in the Sherbrooke-Lewiston area of New Hampshire. The upper member is composed of thickly stratified felsic pyroclastic rocks and volcanic conglomerate, small- to moderate-sized contemporaneous intrusions, iron formations and other exhalites, and wide zones of altered rocks. Tectonic extension is indicated by the presence of an intrusion at Chickwolnepy Stream, a metamorphosed body of tonalite and commonly sheeted gabbro and diabase that is inferred to be comagmatic the the Ammonoosuc Volcanics (Moench, 1990).

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic
Deposit size Small
Significant Yes

Production statistics

  • Year 1910
    Period 1870-1910
    Material ore
    Ore mined 500000mt

Comments on the production information

  • Production from Moench (1990).

Reference information

Bibliographic references

  • Deposit

    Emmons, W.H., 1910, Some ore deposits in Maine and the Milan mine, New Hampshire: U.S. Geological Survey Bulletin 432, 62 p.

  • Geology

    Gair, J. E. and Slack, J.F., 1979, Map showing lithostratigraphic and structural setting of stratabound (massive) sulfide deposits in U.S. Appalachians: U.S. Geological Survey Open-File Report 79-1517, scale 1:1,000,000.

  • Geology

    Moench, R.H., 1990, The Piermont allochthon, northern Connecticut Valley Area, New England -- Preliminary description and resource implications: in Slack, J.F. (editor), Summary results of the Glens Falls CUSMAP Project, New York, Vermont, and New Hampshire: U.S. Geological Survey Bulletin 1887, p. J1-J23.

General comments

Subject category Comment text
Deposit The Milan deposit is a zinc-copper body that has appreciable lead and silver. The geological setting of the Milan deposit, with nearby felsic meta-agglomerate and underlying intensely altered rocks and probable intrusive metafelsite, closely resembles that of the classic Kuroko ores of Japan (Moench, 1990). Sulfides are stratbound and concordant. Sulfides are locally redistributed and enriched in precious metals along cross fractures

Reporter information

Type Date Name Affiliation Comment
Reporter 01-NOV-83 Whitlow, S. U.S. Geological Survey
Editor 04-DEC-03 Woodruff, Laurel G. U.S. Geological Survey Work done in Filemaker

Beyond USGS

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

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