The Hecate Bay occurrence is located 2.2 kilometres southeast of the Catface copper-molybdenum developed prospect (092F 120) and has been explored in conjunction with it and the Irishman Creek (092F 251).
The area is underlain by andesite and basalt flows, breccia and agglomerate, in contact with diorite of the Mesozoic-Paleozoic West Coast Complex. The age of the volcanics is in doubt and they are thought to belong to either the Upper Triassic Karmutsen Formation (Vancouver Group) or to the Devonian Sicker Group. Quartz monzonite of the Jurassic Island Plutonic Suite, has intruded the contact area, followed by several quartz diorite to granodiorite phases of the Early to Middle Eocene Tofino Intrusive Suite.
The Tofino Intrusive Suite phase that hosts the Hecate Bay occurrence is termed the Hecate Bay stock (CIM Special Vol.15, page 304) and has been dated at 48 million years (Geological Survey of Canada Paper 66-17, page 15).
The area of mineralization is in the more porphyritic central portion composed of quartz diorite. The occurrence is circular and approximately 300 metres wide, but copper bearing shears at the periphery extend several hundred metres further. The quartz diorite is moderately fractured, and chalcopyrite and pyrite occur as fracture fillings and disseminations. Copper grades within the shear zones are locally up to 1.0 per cent copper but average only 0.25 per cent copper within the main zone (CIM Special Volume 15, page 309).
Several related occurrences are reported along the shores of Hecate Bay, 1.0 kilometre to the east (CIM Special Volume 15).
In 1963 and 1964, Catface Copper Mines completed programs of soil sampling and a self-potential geophysical survey on the area. In 1970, Fort Reliance Minerals completed a program of soil sampling and a ground magnetic survey. In 1999, Doublestar Resources Ltd. acquired the property from Falconbridge Limited. In 2005, Catface Copper Mines Ltd. and Doublestar had Eagle Mapping conduct a 1:20,000 aerial photographic and 2 metre contour topographic survey over their tenure, including the Hecate Bay showing. In 2007, Doublestar was bought by Selkirk Metals Corp. In November 2009, Selkirk was bought by Imperial Metals Corporation.
Geological reconnaissance completed during the 2014 Catface field program recognized the Hecate Bay tonalite as being generally medium to coarse-grained, equigranular, with weak biotite – silica alteration and relatively heterogeneous. Zones of iron and malachite staining are common. The tonalite is often strongly silicified with up to 20 percent coarse and very fine brown – black biotite and very fine disseminated sulphides (chalcopyrite – bornite(?)). One sample of this mineralized tonalite, located 500 m northwest of the access road, assayed 0.24 percent Cu (ID.780978).
Follow-up soil geochemical sampling in 2016 extended southeast from the previous systematic sampling by Falconbridge in the late 1980’s and over a portion of the Hecate Bay mineralization as it is currently understood. A 600 m wide zone of anomalous copper in soils was identified, open to the northwest and southeast, and follow up prospecting and rock sampling returned grades up to 0.6 per cent Cu in biotite-altered tonalite float samples.
In 2018 an additional program of soil and rock sampling was undertaken to expand the survey coverage in the area of the Hecate Bay Zone. The survey identified a strong NNE-SSW oriented 880 x 700 metre area with greater than 200 ppm Cu. Overlapping this area are coincident and strongly anomalous W, As, anomalies as well as weak Ag anomalies. Flanking the Cu anomaly are strong Pb anomalies. Bi and Au are anomalous over the Cu anomaly but increase at the periphery and flanking the Cu anomaly. Within the copper soil anomaly are highly anomalous regions reaching up to 0.44 per cent Cu with a pronounced increase in grades within the incised creek valleys. Several strongly mineralized angular float samples were taken within creek bottoms given the likelihood of a nearby source. Sample 11201 located within the middle of the copper soil anomaly returned 1.72 per cent Cu, 9.6 grams per tonne Ag, and 0.1 gram per tonne Au. Mineralization consists of disseminated and fracture-controlled chalcopyrite and bornite associated with silica-biotite alteration in a quartz-diorite host. A further 275 metres upstream, angular float sample 11203 returned 0.66 per cent Cu, 3.3 grams per tonne Ag, as well as 0.084 per cent Mo. Approximately 940 metres southwest of the HECATE BAY showing, a recent landslide exposed a small quartz-diorite outcrop with intense quartz-chalcopyrite-pyrite sheeted veins (see HB SLIDE 092F 708).
