The Mill showing is located northwest of the Craig River, approximately 6.5 kilometres south west of its junction with the Jekill River.
The area is underlain by a sequence of metamorphosed Upper Paleozoic rock of the Stikine Assemblage consisting of sediments and volcanics comprised mainly of argillite, chert, quartzite, slate, shale, schist, minor limestone and tuff. The Paleozoic rocks are unconformably overlain by rocks of the Upper Triassic Stuhini Group and the Lower Jurassic Hazelton Group. The stratigraphy is intruded by Late Triassic dioritic and quartz monzonitic plutons, Lower Jurasssic monzodioritic to gabbroic plutons and Eocene plutons (undivided).
The Craig River valley follows a northeast structural trend where extensional faults predominate. The oldest rocks on the property consist of siltstone, cherty siltstone, and chert with minor volcaniclastic interbeds. The feldspar porphyry intrusive is comprised dominantly of coarse-grained, white feldspar phenocrysts, probably orthoclase, in a fine-grained, biotite-feldspar and sericite matrix.
The northwest trending Gossan and Falls Creeks cut the contact zone between the Tertiary feldspar porphyry plug and the Paleozoic metasediments which locally contain disseminated sulphides of pyrite, pyrrhotite and chalcopyrite. Small mylonite zones and some hornfels mark the contact zone. Alteration consists mainly of pyritization and some sericitization.
In 1987, samples were collected from metasediments adjacent to the contact zone. One sample assayed 0.022 per cent copper and another assayed 0.014 per cent copper (Assessment Report 16620).
Work History
The 1983, Cominco Ltd held the Mill 1-7 claims which covered the area immediately west of the Craig River. Work consisted of geological mapping and rock plus soil sampling. A total of 400 hectares was geologically mapped and prospected. Thirty-five rocks and seventy-one soil samples were collected.
In 1987, operator Tanker Oil and Gas Limited conducted a prospecting and geological work program on the Zeehan 8-14 claims that resulted in the collection of 31 heavy mineral concentrate, 90 silt, 169 soil and 160 rock samples. The owner of the property was Skyline Explorations Ltd. At this time the Zeehan 11 claim covered the area of the Mill showing and some geological investigation and sampling occurred.
In 1989 Skyline Explorations Ltd collected a total of 428 contour soil samples, 3 stream silt samples, 15 rock samples and 16 heavy mineral samples from the Zeehan 10, 12 and 13 claims east of the Craig River. The contour soil lines ran from N6 Creek in the northeast to 72K Creek in southwest (Figure 7a, Assessment Report 19366). The widely spaced contour soil lines covered the drainages where documented MINFILE occurrences exist which include: Pyrite Creek (104B 266), Log Jam Creek (104B 265), N2 (104B 267), 72K (104B 304). Prospecting with geological evaluation occurred on known mineral occurrences on the Zeehan 10, 12 and 13 claims. No work was done on the Zeehan 11 claim which covered the Mill showing.