PP

Prospect, Probably inactive

Commodities and mineralogy

Main commodities Cu; Pb; Zn
Other commodities Ag; Au
Ore minerals arsenopyrite; chalcopyrite; galena; marcasite; pyrite; pyrrhotite; sphalerite; tennantite
Gangue minerals calcite; chlorite; dolomite; graphite; quartz; sericite

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale A-1
Latitude 63.1445
Longitude -144.0442
Nearby scientific data Find additional scientific data near this location
Location and accuracy The PP prospect is located between Dry Tok Creek and the Tok River at an elevation of about 5,500 feet. It is about one-half mile east of peak 6660 in the NW1/4 section 26, T. 16 N., R. 7 E., of the Copper River Meridian. The location is accurate.

Geologic setting

Geologic description

The PP massive sulfide prospect is part of a series of massive sulfide occurrences (MH327-MH328, MH350-MH353) that are intermittently exposed along strike for 7 miles in a thrust-repeated section of the lower Lagoon unit (Dashevsky and others, 2003). The mineralized section is as much as 20 feet thick, but the true thickness is difficult to determine due to drag folding and thickening of the mineralized layer or unit (E. Hunter, unpublished data, 1998). Surface samples contain from 0.5 to 1.2 percent copper, 4.0 to 9.1 percent lead, 4.5 to 11.7 percent zinc, 1.0 to 6.0 ounces of silver per ton, and 0.05 to 6.08 parts per million gold. Assays on the limited core recovered from the drilling gave values of 0.5 to 0.9 percent copper, 2.7 to 5.8 percent lead, 4.4 to 9.0 percent zinc, 17 to 28 parts per million (ppm) silver, and 0.05 to 6.08 ppm gold (E. Hunter, unpublished data, 1998). The PP prospect was one of the original massive sulfide discoveries in the Delta District. Surface exposures of massive sulfides as thick as 22 feet have been reported.
The rocks in the vicinity of the PP prospect are mainly north-south-trending metasedimentary rocks with minor bands of quartz-sericite schist of volcanic origin that occur near the massive pyritic sulfide bands. The metasedimentary rocks include interfolded metasiltstone and quartzite, black carbonaceous schist or phyllite, and light gray recrystallized marble (R.A. Blakestad and others, unpublished Resource Associates of Alaska Inc. report, 1976).
Geologic map unit (-144.046441037307, 63.14412139703)
Mineral deposit model Kuroko massive sulfide (Cox and Singer, 1986; model 28a).
Mineral deposit model number 28a
Age of mineralization The lower Lagoon unit, which is part of the metamorphic sequence that includes the rocks at this deposit, has been dated as Devonian on the basis of one SHRIMP U-Pb zircon age of 372 +/- 6 Ma at the nearby LZ East prospect (MH328) (Dashevsky and others, 2003).

Production and reserves

Workings or exploration Extensive field work has been done to evaluate the PP mineralized zone, including geologic mapping, soil sampling, stream-sediment sampling, geophysical surveys, and limited drilling. In 1977 five core holes were drilled on this target, but due to exceptionally poor recovery (about 25 percent), only a few massive sulfide pieces of core were recovered. Surface samples contain from 0.5 to 1.2 percent copper, 4.0 to 9.1 percent lead, 4.5 to 11.7 percent zinc, 1.0 to 6.0 ounces of silver per ton, and 0.05 to 6.08 parts per million gold. Assays on the limited core recovered from the drilling gave values of 0.5 to 0.9 percent copper, 2.7 to 5.8 percent lead, 4.4 to 9.0 percent zinc, 17 to 28 parts per million (ppm) silver, and 0.05 to 6.08 ppm gold (E. Hunter, unpublished data, 1998).
Indication of production None

Additional comments

The unpublished data that is cited can be seen by contacting Grayd Resources Inc. in Vancouver, B.C., Canada (www.grayd.com), or Northern Associates Inc. in Fairbanks, Alaska.

References

References

Reporters W.T. Ellis (Alaska Earth Sciences), A.S. Wyatt and S.S. Dashevsky (Northern Associates, Inc. ), and W.J. Nokleberg (USGS)
Last report date 3/20/2003