52 Porphyry Zone

Prospect, Active

Commodities and mineralogy

Main commodities Cu
Other commodities Ag; Au; Mo
Ore minerals chalcopyrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale IL
Quadrangle map, 1:63,360-scale D-7
Latitude 59.8081
Longitude -155.5102
Nearby scientific data Find additional scientific data near this location
Location and accuracy The 52 Porphyry Zone prospect is at an elevation of about 1,400 feet on the side side of a knob about 4.2 miles northwest of Sharp Mountain. The center of the drilling is about 0.5 mile north of the center of section 29, T. 4 S., R. 36 W.

Geologic setting

Geologic description

The 52 Porphyry Zone was discovered by drill testing a copper soil-geochemistry anomaly coincident with an IP geophysical anomaly (Rebagliati, 2003). Four holes were drilled in an area about 400 meters long. Surface rubble and drill core indicate that the entire area is underlain by black fine- to medium-grained basalt similar to that found as the '37 Skarn' prospect (IL002) about a mile to the south. The basalt has been weakly propylitically altered to epidote and chlorite. Modest amounts of chalcopyrite occur in fracture fillings with potassium feldspar and chlorite. The prospect has low-grade copper mineralization with porphyry affinities as suggested by the nearby Pebble prospect (IL007) and other prospects in the Pebble claim block.
Geologic map unit (-155.512390435596, 59.8074047757047)
Mineral deposit model Chalcopyrite along fractures in basalt. Probable porphyry copper affinities.
Age of mineralization Probably Late Cretaceous, about 90 Ma, by analogy with the nearby Pebble deposit (IL007).
Alteration of deposit Weak propylitic and potassium-feldspar alteration.

Production and reserves

Workings or exploration The area has been covered by extensive geochemical and geophysical surveys beginning in about 1986 as part of the exploration of the Pebble block of claims Teck-Cominco, and through early 2011 by Northern Dynasty Minerals Ltd. Considerable mapping and sampling at the surface; 4 holes drilled in 2002.
Indication of production None
Reserve estimates None.
Production notes None.



Gaunt, J.D., Rebagliati, C.M., Lang, James, Titley, Eric, Melis, Lawrence, Barratt. Derek, and Hodgson, Stephen, 2010, Technical report on the 2009 program and update on metallurgy, Pebble copper-gold-molybdenum project, Iliamna Lake area, southwestern Alaska, U.S.A: Unpublished Technical Report for Northern Dynasty Minerals Ltd., 195 p. (posted on www.sedar.com, Mar. 18, 2010).
Rebagliati, C.M., 2003, Summary report on the Pebble copper-gold porphyry project; Unpublished report for Northern Dynasty Minerals Ltd., 94 p. (posted on www.sedar.com, Feb. 13, 2003.)
Reporters C.C. Hawley (Hawley Resource Group); D.J. Grybeck (Contractor, USGS)
Last report date 2/28/2011