Heckman

Past Producer in Alaska, United States with commodities Gold, Lead, Zinc

Geologic information

Identification information

Deposit ID 10094032
MRDS ID A012330
Record type Site
Current site name Heckman
Alternate or previous names Unnamed (northwest of Heckman prospect)
Related records 10185920

Geographic coordinates

Geographic coordinates: -131.61871, 55.2928 (WGS84)
Relative position This site is in section 8, T. 76 S., R. 91 E., of the Copper River Meridian. It includes two, closely-spaced, deposits at sea level on southeastern Gravina Island opposite Pennock Island. They are the Heckman mine, which is about 0.3 mile from Gravina Point, and an unnamed prospect about 0.3 mile northwest of the Heckman. The coordinates of the map site are for the Heckman prospect. The site corresponds to loc. 71 in Elliott and others (1978), and to locs. 287 and 288 in Maas and others (1995). The location of the Heckman mine is accurate within 0.1 mile.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary
Lead Secondary
Zinc Secondary

Materials information

Materials Type of material
Galena Ore
Gold Ore
Pyrite Ore
Sphalerite Ore
Calcite Gangue
Quartz Gangue

Mineral occurrence model information

Model code 91
USGS model code 24b
Deposit model name Massive sulfide, Besshi (Japanese deposits)
Mark3 model number 30
Model code 85
USGS model code 22c
Deposit model name Polymetallic veins
Mark3 model number 46

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Schist
    Stratigraphic age (youngest) Late Cretaceous

Nearby scientific data

(1) -131.61871, 55.2928

Comments on the geologic information

  • Geologic Description = The country rocks on southeastern Gravina Island are Upper Jurassic or Cretaceous marine andesitic or basaltic volcanic rocks that are gradationally interbedded with subordinate flyschlike sedimentary rocks (Berg, 1973; Berg and others, 1988). The strata were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time. The country rocks are cut by a high-angle fault along Tongass Narrows that displays about 4 miles of right-lateral offset.? Maas and others (1995, p. 194, 199, 201-202, and fig. 51) describe the Heckman prospect, and a similar unnamed lode about 0.3 mile to the northwest, as stratiform, sulfide-bearing, northwest-trending layers of greenschist or quartz-chlorite schist, locally cut by sulfide-bearing quartz fissure veins. At the Heckman prospect, pyrite, sphalerite, and galena occur as bands of massive sulfides, and as disseminations, in several layers of quartz-chlorite schist, separated by several layers of relatively barren schist.?The sulfides also occur in quartz stringers parallel to the foliation of the schist. The stratiform deposit, as exposed in old trenches, is at least 25 feet wide and 60 feet long. Samples of this deposit indicated a zone up to about 10 feet wide containing 6.2 ppm Au and 1.6% Zn. The other prospect, at sea level about 0.3 mile northwest of the Heckman prospect, consists of talc-chlorite schist that contains pyrite, sphalerite, and galena disseminated in quartz-rich layers parallel to the foliation of the schist. ? Brooks (1902, p. 62) interpreted the Heckman deposit as the southeast continuation of the deposit at the Goldstream (Bell) mine (KC072). Maas and others (1995, p. 194, 201) suggest that the stratiform deposits are of volcanogenic origin. If so, the Heckman probably can be classified as a metamorphosed Besshi massive sulfide deposit of Late Jurassic age. The sulfide-bearing quartz fissure veins that cut the foliation probably formed by remobilization, during or following Upper Cretaceous regional metamorphism.? These prospects were discovered in the early 1900s (Brooks, 1902, p. 62; Wright and Wright, 1908, 179). The Heckman was explored at that time by a 60-foot shaft, and drifts totalling 32 feet. The other prospect was explored by a 50-foot shaft.
  • Age = Late Jurassic; Late Cretaceous or younger.

Economic information

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic

Mining district

District name Ketchikan

Comments on the production information

  • Production Notes = There is no public record of any production from the Heckman mine, but the extent of the underground workings suggests that at least a small amount of gold was recovered in the early 1900s.

Comments on the workings information

  • Workings / Exploration = These prospects were discovered in the early 1900s (Brooks, 1902, p. 62; Wright and Wright, 1908, 179). The Heckman was explored at that time by a 60-foot shaft, and drifts totalling 32 feet. The other prospect was explored by a 50-foot shaft. Samples collected by Maas and others (1995) of the Heckman deposit indicated a zone up to about 10 feet wide containing 6.2 ppm Au and 1.6% Zn.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A012330
USGS Alaska Resource Data File ARDF KC074

Bibliographic references

  • Deposit

    Brooks, A.H., 1902, Preliminary report on the Ketchikan mining district, Alaska, with an introductory sketch of the geology of southeastern Alaska: U.S. Geological Survey Professional Paper 1, 120 p.

  • Deposit

    Wright, F.E., and Wright, C.W., 1908, The Ketchikan and Wrangell mining districts, Alaska: U.S. Geological Survey Bulletin 347, 210 p.

  • Deposit

    Berg, H.C., 1973, Geology of Gravina Island Alaska: U.S. Geological Survey Bulletin 1373, 41 p.

  • 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.

  • 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.

  • 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.

Comments on the references

  • Primary Reference = Berg, 1973; Maas and others, 1995

General comments

Subject category Comment text
Deposit Model Name = Besshi massive sulfide?; Polymetallic veins (Cox and Singer, 1986; models 24b, 22c)
Deposit Model Number = 24b?, 22c
Deposit Other Comments = Brooks (1902, p. 62), noting their similarity, interpreted the Heckman deposit as the southeast continuation of the deposit at the Goldstream (Bell) mine (KC072). ? Also see Production notes.

Reporter information

Type Date Name Affiliation Comment
Reporter 03-JUL-1999 H.C. Berg U.S. Geological Survey