The Porphyry zone mapping has outlined a series of mineralized pods trending east to northeast over a distance of 200 metres within feldspar porphyry of the Lower Jurassic Hazelton Group. The area of the mineralized pods is up to 12 metres long and 5 metres across and clustered along the northeastern margin of the porphyry dome covering an area 100 by 200 metres.
Sampling in this area has yielded values of up to 6.48 grams per tonne gold and 9.94 grams per tonne silver over 1.0 metre (Assessment Report 20030). At least thirteen trenches and one shallow adit have been blasted by previous workers (prior to 1989 Calpine work) in the zone to better expose the mineralization.
These pods are typically flooded by quartz stringers (up to 20 per cent by volume). Both the stringers and the porphyry host contain up to 60 per cent pyrite (disseminations and blebs), 2 per cent sphalerite, 2 per cent galena and 1 per cent chalcopyrite.
A few hundred metres south of the Porphyry zone an old trench (the KD trench) was sampled. The material consists of black argillite and lesser andesite tuff, both containing stringers and blebs of up to 25 per cent pyrite, 5 per cent sphalerite and 1 per cent galena.
Work History
Little or no work has been recorded on the GNC claims prior to 1982, however much work has been done on the adjoining Tok, Ray and Sib claims which covered the Eskay mine (MINFILE 104B 008).
In 1982 Ryan Explorations carried out stream sediment sampling, some of which was on the later GNC claims. Several anomalous gold values were reported from streams draining the GNC claims.
An airborne geophysical survey (EM-VLF and magnetics) was flown over the GNC claims in early 1989 as part of a survey for Calpine Resources Inc. including other properties in the Eskay Creek area (Assessment Report 18964). A total of 514.7 kilometers was claimed by Calpine for the GNC property.
In 1989 a field program was conducted by Calpine Resource. Geological mapping at a scale of 1:2500 was undertaken as the grid cutting was in progress. The Porphyry and Tip Top zones were mapped in detail at a scale of 1:1000. A combined magnetometer and VLF-EM survey was implemented over 18.1 kilometres of cut grid. Selected test lines were also covered by an induced polarization survey, including the Porphyry zone which was given detail coverage at 50 metre line spacings. The total IP coverage amounted to 12.5 line kilometres. Soil sampling (1262 samples) was conducted over the cut lines with samples collected at 25 metre and 12.5 metre intervals over the detail grids. In 1993, Homestake drilled one hole on the GNC 1 at a UTM coordinate of about 409620 East, 6277200 North in order to test for Eskay Creek, 21B style mineralization. Drilling during 1991 and 1992 on this area (the McKay West Target) defined an anomalous area with gold, zinc, antimony and arsenic values in mudstone near the top of the rhyolite. No potentially economic concentrations of base or precious metals were intersected in Hole 93-33 (Assessment Report 23193).
It appears that at some point, soon after 1993, the GNC 1-3, IKS 1 and several other Tok and Kay claims became permanent lots attached to the Eskay Creek mine (104B 008).
In 2019, Skeena Resources completed a minor prospecting and sampling program on the area as part of the Eskay Creek project. Two grab samples from the Eskay Porphyry zone yielded 1.7 and 7.1 grams per tonne gold with 5 and 9 grams per tonne silver, respectively (SRK Consulting (Canada), Inc. [2021-05-21]: Independent Technical Report on the Eskay Creek Au-Ag Project, Canada).
The following year, a three-dimensional resistivity and induced polarization survey was completed on the property.
See the nearby Tip Top (MINFILE 104B 591) showing.
