The Schaft Creek porphyry copper-molybdenum deposit is located on the western flank of a complex belt of rocks up to 10 kilometres wide and 50 kilometres long between Mess and Schaft creeks. This belt is overlain east of Mess Creek by a broad north trending belt of Cenozoic volcanics, while west of Schaft Creek three different intrusive units have formed another broad north trending belt. The deposit occurs near the eastern margin of one of these units, the Middle(?) Triassic-Middle Jurassic Hickman batholith, a crudely zoned complex with a core of pyroxene diorite grading to biotite granodiorite at the edges. North of this batholith is a massive Tertiary-Cretaceous quartz monzonite, which intrudes both the batholith, and a Juro-Cretaceous granodiorite to quartz diorite intrusion.
Major north-striking faults occupy the valley of Mess and Schaft creeks near the boundaries of the belt. The terrain between the creeks is underlain by complex stratigraphy composed mainly of Upper Triassic andesitic tuffs, flows, breccias and derived sediments. The oldest rocks in the belt are Permian limestones that appear to be in fault contact with the volcanics. Upper Triassic basaltic augite porphyry occurs as large dike-like bodies cutting the volcanic pile. Quartz monzonite and dioritic rock related to the three intrusions, form small stocks and tabular bodies throughout this belt. Souther (Geological Survey of Canada Map 11-1971) also describes an area of Lower Jurassic conglomerate a few kilometres to the north of this occurrence. Rhyolite and diabase dikes of probable Cenozoic age are also numerous.
Mineralization occurs partly within a basin-like structure of fragmental and undivided green andesites, 900 metres in diameter. The basin is intruded by augite porphyry basalt and by vertical north striking quartz diorite dikes. A breccia cuts the western edge of the basin and trends north for at least 2700 metres. Post-mineralization mafic dikes are common. Later flat-lying fragmental purple andesites unconformably overlie the northeastern part of the deposit (Canadian Institute of Mining and Metallurgy June 1975).
In general, pyrite, chalcopyrite, bornite and molybdenite occur predominantly in fractured andesites. Less than 10 per cent of the mineralization occurs in felsic intrusives. Pyrite and bornite are mutually exclusive and most of the main deposit occurs within the bornite zone, with pyrite on the periphery. A barren zone, which contains no sulphides, conformably underlies the main deposit.
The main deposit is generally conformable with the lithological basin, but cuts its northern wall. A core of low-grade mineralization occurs in the northern half of the deposit. Two much smaller, but somewhat higher grade deposits are associated with the breccia.
1. The broad, northerly plunging Liard. or Main, zone extends 1,000 metres in a northerly direction, 700 metres east-west, and has average thickness of 300 metres. A pyrite halo surrounds chalcopyrite, bornite and molybdenite mineralization in altered and faulted andesite. The zone has a low grade phyllic core and to the northwest is progressively down dropped on faults.
2. The West Breccia zone exhibits tourmaline, silicification and sencitization and is controlled by north-trending faults. It is 500 metres in length, averages 100 metres in width and has been drilled to depths greater than 300 metres. Pyrite is the principal sulphide mineral, with lesser quantities of chalcopyrite and molybdenite. Copper and molybdenum contents are erratic but often high.
3. The Paramount zone of intrusive breccia occurs in granodiorite and quartz monzonite and has dimensions 700 metres length, 200 metres width of over 500 metres thickness. Exploration to the north has been constrained by practical considerations: rapidly increasing thicknesses of overlying apparently barren purple volcanic rocks challenge drilling methods and work against practical open pit designs. Pyrite, bornite and chalcopyrite are present in equal proportions and molybdenite values exceed those found in the other two zones.
Feldspathization and hydrothermal alteration are associated with mineralization. A quartz vein stockwork with biotite and some potassium feldspar coincides with the low-grade core of the main deposit. The biotite has a potassium/argon age of 182 Ma +/- 5 Ma (Canadian Institute of Mining and Metallurgy June 1975). Epidote appears abruptly near the boundaries of the main deposit. Most mineralization occurs in an intermediate zone marked by chlorite-sericite alteration and the absence of epidote. Tourmaline and gypsum are locally abundant.
The distribution of most sulphide minerals is fracture-controlled. They occur in dry fractures or combined with quartz or quartz-calcite veinlets within the andesitic volcanics. The sulphides within the felsic intrusives are usually disseminated and seem to have replaced the mafic minerals. Trace amounts of covellite, chalcocite, tetrahedrite and native copper have been identified. Minor amounts of galena and sphalerite occur in the breccia zone and in small calcite veins. Gold and silver are associated with the sulphides and average 0.34 grams per tonne and 1.71 grams per tonne, respectively.
By 1976, mineable reserves calculated at an open pit stripping ratio of 1.5 (waste) to 1 (ore) were 330 million tonnes grading 0.4 per cent copper and 0.02 per cent molybdenum; preliminary estimates indicate that the mineralization will grade approximately 0.32 part per million gold and 1.5 parts per million silver (CIM Special Volume 15 (1976), page 219).
Current theories of mineral genesis are controversial. Seraphim and Sutherland Brown (Canadian Institute of Mining and Metallurgy Special Volume 15, page 219) agree with Linder, preferring an explanation that the deposit is almost syngenetic, in part strata controlled, and directly linked to near surface volcanic activity. However, most experts still classify it as a porphyry.
The Schaft Creek prospect was located in 1957 by prospector Nick Bird who was employed by BIK Syndicate, a consortium of Silver Standard Mines Ltd., McIntyre Porcupine Mines Limited, Kerr Addison Mines Ltd. (now Noranda Inc.) and Dalhousie Oil Ltd. The prospecting syndicate was re-organized in 1966 into Liard Copper Mines Ltd. in order to recognize the respective interests of its members; Silver Standard Mines Limited, with a 66 per cent interest, was the manager.
ASARCO in 1966 obtained an option to explore the Liard Copper Mines Ltd. ground, carried out geological and induced polarization surveys and drilled 10,939 feet in 24 holes (Jeffrey, 1966). The option, despite encouraging drill results, was not maintained and in 1966 Hecla Mining Company of Canada Limited, a subsidiary of Hecla Mining Company of Wallace, Idaho, entered an option agreement to earn a 75 per cent property interest and, with Hecla Operating Company as its agent, commenced drilling and other exploration work.
Hecla, in the period 1966 through 1977, completed 34,500 metres of BQ and NQ-size core drilling, 6,560 metres of percussion drilling, comprehensive induced polarization and resistivity surveys, geological mapping, both detailed and reconnaissance, petrographic studies, and air photography, and commenced engineering studies related to development of a large open pit copper-gold molybdenum mine. Property work ceased in 1977 and in 1976 Hecla sold its interest to Teck Corporation.
In 1980, Teck commenced a program of exploration and drilling designed to confirm and expand Hecla’s work. A total of 26,000 metres of drilling NQ and HQ core was completed by 1981. Teck then undertook an engineering study to determine the feasibility of mine development. Further data reviews were completed by Western Copper Holdings in 1988 and Tack in 1993. The property has been on a ‘hold’ basis since that time and in 2002, Salazar obtained an option to acquire 100 per cent of Teck’s interest.
Between 1968 and 1981, 60,200 metres of core drilling in 230 holes were completed which outlined a proven and probable open pit resource of 971,495,000 tonnes grading 0.298 per cent copper, 0.02 per cent molybdenum (0.033 per cent MoS2), 0.14 gram per tonne gold and 1.2 grams per tonne silver (CIM Special Volume 46, pages 239-246).
In 2003, it was reported that Guillermo Salazar entered into an agreement to acquire all of Teck’s interest in the property who then assigned his interest to 955528 Alberta Ltd. In 2004 it was reported that the owners were Teck Cominco Limited, 955528 Alberta Ltd. and Liard Copper Mines Ltd. (previously 78 per cent Teck owned). Old core that was stored on the property in a weatherproof building was sampled in order to conduct metallurgical test work. In 2004, Copper Fox Metals Inc. agreed to acquire the Schaft Creek porphyry copper deposit (MINFILE 104G 015) from 955528 Alberta Ltd.
Copper Fox Metals Inc collected material for a metallurgical study from the deposit by drilling 3,161 metres of P-size core in 15 holes. Based on 60,000 metres of prior drilling, Copper Fox estimates Schaft Creek to contain a combined Measured and Indicated resource of 332 million tonnes grading 0.39 per cent copper, 0.026 per cent molybdenum and 0.267 gram per tonne gold, at a 0.4 per cent copper equivalent cut-off (Exploration in BC 2005, page 30). Most of the current drilling twinned historic holes, to validate assay data and to gain a better assessment of gold content. Copper Fox also began environmental and road access studies, and plans to enter the Environmental Assessment process in early 2006.
In 2007 Copper Fox Metals announced an updated combined Measured and Indicated resource estimate of 1,393.30 million tonnes grading 0.25 per cent Cu, 0.019 per cent Mo, 0.18 gram per tonne Au, and 1.55 gram per tonne Ag using a 0.2 per cent copper equivalent cut-off (www.copperfoxmetals.com).
During 2011, Copper Fox focused its exploration efforts on evaluating the mineral potential of the Schaft Creek project, completed additional land acquisitions, metallurgical test work on the mineralization from the Paramount zone and 22 diamond drill holes for various purposes totaling 9662.3 metres. During 2011, Precision GeoSurveys Inc. completed a high resolution aeromagnetic total field magnetic survey over a large portion of the Schaft Creek project (Assessment Report 33242). A total of 2,520 line kilometers of magnetic data were flown for this survey; including tie lines and survey lines. The survey lines were flown at 200 metre spacing at a 090 degrees/270degrees. The airborne magnetic survey identified 3 distinct positive magnetic signatures that correlate with the Schaft Creek deposit and the ES and GK zones of copper mineralization.