Iron No. 1-4

Prospects, Undetermined

Alternative names

Shaft Creek Copper

Commodities and mineralogy

Main commodities Ag; Au; Cu
Ore minerals arsenopyrite; chalcopyrite; galena; pyrrhotite; sphalerite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale BC
Quadrangle map, 1:63,360-scale A-1
Latitude 56.006
Longitude -130.038
Nearby scientific data Find additional scientific data near this location
Location and accuracy This site consists of a 0.6-mile-long, north-northeast-trending line of prospects in Section 1 between elevations 2600-3250 feet on the divide between Skookum and Fish Creeks (Maas and others, 1995, p. 252 and fig. 66). The above coordinates are for the approximate center of this line of prospects, all of which are within a half-mile of the map location.

Geologic setting

Geologic description

The country rocks in the general area of this site are pelitic metasedimentary and subordinate andesitic metavolcanic (greenstone) strata of the Jurassic or older Mesozoic Hazelton Group; the Triassic Texas Creek Granodiorite, which underlies and locally intrudes the Hazelton; the Eocene Hyder Quartz Monzonite, which intrudes the Hazelton and Texas Creek rocks; and still-younger Tertiary lamprophyre dikes, which cut all the other rocks (Smith 1973, 1977; Koch, 1996).
Maas and others (1995, p. 252, 260) describe the deposits as veins, disseminations, and masses of gold-bearing pyrrhotite with associated chalcopyrite and arsenopyrite, and local sphalerite and galena. Individual mineralized zones range from about 60-450 feet wide and are located near or in shears in Hazelton volcanic rocks (greenstone). The prospects roughly align with the contact between Hazelton volcanics and Texas Creek Granodiorite, and are never more than about 1300 feet in lateral distance from the surface exposure of that contact.
Maas and others (p. 252) suggest that the age of the deposits is Jurassic, based on similarities in mineralogy, structural setting, and hostrock, with isotopically-dated Jurassic deposits nearby in the Hyder district (for example, see BC065, 067), and at the Scottie gold mine nearby in British Columbia (Alldrick, 1993). If so, the deposits are contemporaneous, at least in part, with island-arc volcanism in Hazelton time (Alldrick, 1993).
Geologic map unit (-130.039704261687, 56.0057059052064)
Mineral deposit model Polymetallic veins (Cox and Singer, 1986; model 22c).
Mineral deposit model number 22c
Age of mineralization Maas and others (1995, p. 252) suggest that the age of the deposits is Jurassic, based on similarities in mineralogy, structural setting, and hostrock, with isotopically-dated Jurassic deposits nearby in the Hyder district (for example, see BC065, 067), and at the Scottie gold mine nearby in British Columbia (Alldrick, 1993). If so, the deposits are contemporaneous, at least in part, with island-arc volcanism in Hazelton time (Alldrick, 1993).
Alteration of deposit Volcanic (greenstone) hostrocks are impregnated with sulfide minerals.

Production and reserves

Workings or exploration
The prospects have been explored by small pits and trenches; there is a flooded shaft on Shaft Creek Copper prospect.
Various samples of the deposits collected by the U.S. Bureau of Mines in 1992 or 1993 (Maas and others, 1995. p. 260) contain up to 14.74 ppm Au (Iron No. 2), 64.11 ppm Ag (Iron No. 4), 17.3 percent Cu (Shaft Creek Copper), 6370 ppm Pb (Iron No. 4), and 6840 ppm Zn (Iron No. 4).
Indication of production Yes; small
Production notes Small amount of ore stored at Shaft Creek Copper prospect.

References