Unnamed (adjacent to Helen S Mine)

Prospect, Active

Commodities and mineralogy

Main commodities Ag; Au; Cu; Pb; Zn
Other commodities Ba
Ore minerals arsenopyrite; chalcopyrite; galena; pyrrhotite; sphalerite
Gangue minerals barite; quartz

Geographic location

Quadrangle map, 1:250,000-scale PE
Quadrangle map, 1:63,360-scale C-4
Latitude 56.5693
Longitude -133.0683
Nearby scientific data Find additional scientific data near this location
Location and accuracy This deposit adjoins or overlaps the veins at the Helen S Mine (PE028). At this prospect, volcanogenic massive sulfides are exposed in several pits and occur in float for about 700 feet along a small south-flowing creek whose mouth is about 50 yards north of the mouth of the creek that drains Harvey Lake on Woewodski Island. The coordinates are at a pit with the best exposed mineralization; it is about 400 feet north of the high-tide line in southwest corner of section 22, T. 61 S., R 79 E. Figure 15 of Still and others is a detailed map of this mineralization and the Helen S Mine.

Geologic setting

Geologic description

This volcanogenic massive-sulfide deposit is within the old claim of the Helen S Mine (PE028). The massive sulfides are present in several pits that may date back to the early 1900s. However, the massive sulfides were not recognized until 1980 (Berg and Grybeck,1980). Subsequently, the deposit has been examined by numerous geologists and it was examined and sampled by Still and others (2002) as part of a regional mineral assessment for the Bureau of Land Management.
The rocks in the area are mainly metamorphosed felsic and intermediate flows and breccia and argillite of the Triassic Hyd Group that have been intruded by Mesozoic hornblende gabbro exposed just a few hundred feet to the west and Cretaceous diorite a mile to the south (Brew, 1997; Karl and others, 1999).
The best exposure of the massive sulfide mineralization is in an old pit about 400 feet north of the site of the old Helen S mill. The massive sulfides consist of crudely banded pyrite, pyrrhotite(?), arsenopyrite, sphalerite, and galena with barite in greenstone and greenschist. Similar mineralization occurs in several small pits and in float for about 400 feet north along a small creek. Still and others (2002) collected several samples in the southern pit; selected samples contained up to 113.5 parts per million (ppm) silver, up to 2.5 percent lead, and 3.0 percent zinc. Samples from the northern pits contained up to 2.13 ounces of silver per ton, 1.74 percent lead, and 8.5 percent zinc. The massive sulfide deposits do not contain detectable gold as distinct from the gold-quartz veins of the adjacent Helen S Mine. Berg and Grybeck (1980) interpreted the massive sulfides as part of the Duncan-Zarembo belt of dismembered, Upper Triassic volcanogenic massive sulfide deposits.
Geologic map unit (-133.070023113962, 56.5689545170668)
Mineral deposit model Barite facies of a Kuroko massive-sulfide model (Cox and Singer, 1986; model 28a); or alternatively a barite facies of a Sierran Kuroko model (Bliss, 1992; model 28a.1).
Mineral deposit model number 28a or 28a.1
Age of mineralization The volcanogenic massive sulfides in the Duncan-Zarembo belt are Upper Triassic (Berg and Grybeck, 1980).

Production and reserves

Workings or exploration This volcanogenic massive-sulfide deposit is within the old claim of the Helen S Mine (PE028). The massive sulfides are present in several pits that may date back to the early 1900s. However, the massive sulfides were not recognized until 1980 (Berg and Grybeck, 1980). Subsequently, the deposit has been examined by numerous geologists and it was examined and sampled by Still and others (2002) as part of a regional mineral assessment for the Bureau of Land Management.
Indication of production None
Reserve estimates None.

Additional comments

All the workings are on a patented claim.

References

MRDS Number A010326

References

Still, J.C., Bittenbender, P.E., Bean, K.W., and Gensler, E.G., 2002, Mineral assessment of the Stikine area, central Southeast Alaska: U.S. Bureau of Land Management Technical Report 51, 560 p.
Reporters D.J. Grybeck (Port Ludlow, WA)
Last report date 3/4/2008