The Louise Lake copper-molybdenum-goldarsenic high level porphyry system, west-central British Columbia

Special Volume, Vol. SV 46, No. 1995, 1995

The Louise Lake Cu-Mo-Au-As high level porphyry system, located 33 km west of Smithers, British Columbia, has been explored by several companies since its discovery in 1968. The property is situated in the Intermontane tectonic belt near the western end of the Skeena arch. A regional scale fault occupying the Coal Creek Lineament separates Skeena Group sedimentary rocks on the northwest from Hazelton Group volcanic rocks on the southeast. Alteration and mineralization are controlled by a 100m thick swarm of moderately northwest-dipping feldspar porphyry sills that intrude Skeena Group sedimentary rocks. Primary mineralization consists of disseminated and fracture-controlled pyrite, tennantitel enargite, chalcopyrite, and molybdenite, with minor secoruiary chalcocite and bornite. Gold is probably associated with the tennantitelenargite. A geological resource of 50 million tonnes grading 0.3o/o Cu, 0.3 gl t Au, and 0.02% Mo has been calculated using a cutoff of0.2o/o Cu. The geometry of the porphyry intrusions, the phyllic-argillic alteration zoning, and the unusual presence of tennantitelenargite indicate that the deposit formed near the top of a porphyry hydrothermal system.

Keywords: Porphyry system, Mineralization, Tennantite, Enargite