The K-7 prospect is situated on a ridge separating Homestake and Johnson creeks, approximately 21 kilometres east-southeast of Barriere and 60 kilometres northeast of Kamloops.
The area is underlain by four thrust-bounded sub-assemblages of the Early Cambrian to Late Mississippian Eagle Bay Formation: the Rea, Plateau, Homestake and Acacia assemblages. The Rea assemblage, which underlies the immediate area of the Twin occurrence, consists of a structurally inverted sequence of mafic pyroclastics and flows containing Tshinakin limestone. The mafic series is stratigraphically overlain and structurally underlain by a thick sequence of clastic sediments. The Rea zone, a 10 to 150-metre-thick section of stratigraphy at the mafic volcanic-sediment contact, hosts the Rea Gold (MINFILE 082M 191), K-7 and Twin (MINFILE 082M 276) occurrences. The Plateau assemblage lies to the southwest and consists of mafic, intermediate and felsic volcanics with lesser interbedded argillite. Structurally underlying the Plateau assemblage is the Homestake assemblage, which consists of five distinct units consisting of calcareous sediments, mafic volcanics, sericite schists, interlayered sericite schist, phyllite, chert and argillite and unaltered felsic volcanics. Further south, well-bedded and complexly folded quartzites, quartz wackes, siltstones and argillites comprise the Acacia assemblage.
The Eagle Bay assemblage has a complex deformational history involving multiple stages of thrust faulting and folding during the Jura-Cretaceous, which produced strongly foliated and overturned rocks trending northwest and dipping northeast. These Paleozoic rocks are intruded by Mid-Cretaceous granodiorite and quartz monzonite (such as the Baldy Batholith, approximately 30 kilometres to the north of the deposit), and Early Tertiary quartz-feldspar porphyry, basalt and lamprophyre dykes. These are all locally overlain by Miocene plateau lavas, now represented in the area by occasional erosional remnants.
The area can be divided into several northwest-trending, northeast-dipping units. From northeast to southwest, these are the following units: 1) the Tshinikan Limestone, which forms steep, massive landforms dominating the area; 2) mixed sediments consisting of interbedded cherts and argillite; 3) mafic volcanics; 4) the "Mine Series" of rocks, consisting of a zone of more mixed sediments and mafic volcanics, with minor felsic to intermediate volcanics, which form the host stratigraphy for the Samatosum and Discovery or Rea Gold zone (MINFILE 082M 191) deposits; and finally, 5) a thick unit of argillites and wackes and a package of felsic rocks that lie in the structural footwall of the Mine Series. See the Samatosum past producer (MINFILE 082M 244) for further details of area geology.
In 1986, drillhole KAM-3, located approximately 450 metres to the west-northwest of the K-7 occurrence, yielded 0.850 gram per tonne gold over 1.5 metres, whereas another drillhole (KAM-6), located approximately 400 metres southwest of the K-7 occurrence, yielded 0.245 per cent lead, 0.409 per cent zinc and 2.4 grams per tonne silver over 1.5 metres (Assessment Report 15754).
From the 1988 drill program, one diamond drill hole (K88033) intersected intensely dolomitized mafic volcanics from 2.6 to 32.1 metres; these volcanics form the footwall of the Rea zone. Massive polymetallic sulphides (32.1 to 34 metres) were found in sharp contact with the volcanics. The sulphides were medium grained and crudely banded on a centimetre scale. Bands of massive chalcopyrite and sphalerite-galena were also observed, as were "splashes" of galena and chalcopyrite up to 2 centimetres across. A weighted average of four assays yielded 1.82 metres of 1.26 per cent copper, 6.51 per cent lead, 6.87 per cent zinc, 53.51 grams per tonne silver, 7.54 grams per tonne gold and 5.3 per cent arsenic (Assessment Report 18822, page 9). Another drill hole (K88040) intersected semi-massive sulphides from 108.8 to 110.6 metres and banded, medium-grained, polymetallic massive sulphides from 110.6 to 120 metres. Assays from an 11.6-metre section yielded 0.56 per cent copper, 6.85 per cent lead, 8.4 per cent zinc, 77.8 grams per tonne silver, 3.56 grams per tonne gold and 2.65 per cent arsenic (Assessment Report 18822, page 17). The K-7 zone has been traced by trenching and drilling over an area approximately 100 to 200 metres wide and for approximately 700 metres along strike.
Other drilling intercepts from the K-7 zone included 0.06 per cent copper, 0.43 per cent lead, 1.74 per cent zinc, 4.5 grams per tonne silver and 1.70 grams per tonne gold over 3.60 metres in hole K88034; 0.15 per cent copper, 1.01 per cent lead, 0.70 per cent zinc, 9.0 grams per tonne silver and 0.92 gram per tonne gold over 2.40 metres in hole K88035; 0.16 per cent copper, 2.48 per cent lead, 3.90 per cent zinc, 22.2 grams per tonne silver and 0.96 gram per tonne gold over 7.05 metres in hole K88036; 0.41 per cent copper, 3.20 per cent lead, 4.23 per cent zinc, 40.4 grams per tonne silver and 1.99 grams per tonne gold over 6.11 metres in hole K88041; 0.12 and 0.18 per cent copper, 0.99 and 0.57 per cent lead, 1.56 and 1.00 per cent zinc, 92.0 and 16.8 grams per tonne silver with 5.01 and 2.23 grams per tonne gold over 0.5 and 1.0 metres, respectively, in hole K88044 and 0.11, 0.53 and 0.44 per cent copper, 0.52, 2.41 and 2.68 per cent lead, 1.07, 3.58 and 3.59 per cent zinc and 9.8, 68.4 and 91.5 grams per tonne silver with 1.41, 9.92 and 4.92 grams per tonne gold over 3.6, 2.3 and 0.5 metres, respectively, in hole K88047 (Assessment Report 18822).
A resource for the K-7 zone, attributed to Kamad Silver Company, was reported to be 375,000 tonnes grading 4 grams per tonne gold, 55 grams per tonne silver, 0.5 per cent copper, 4.8 per cent lead and 6.1 per cent zinc (Assessment Report 22389, page 1).
In 2000, a sample (10420) of massive sulphides from a southern K-7 zone trench yielded 1.05 per cent copper, 7.82 per cent lead, 3.12 per cent zinc, 65.8 grams per tonne silver and 4.48 grams per tonne gold (Assessment Report 26595).
In 2003, three float samples (EH-01, -02 and -03) were collected from the north end of the No. 1 trench and yielded values from 0.94 to 38.4 grams per tonne gold, 64.8 to 72.8 grams per tonne silver, 0.43 to 0.82 per cent copper, 6.48 to 11.6 per cent lead and 2.08 to 2.94 per cent zinc (Assessment Report 27171).
In 2004, trenching on the K-7 zone yielded values of up to 51.2 grams per tonne gold, 834 grams per tonne silver, 0.309 per cent copper, 15.52 per cent lead and 0.393 per cent zinc over 5.5 metres in trench 4, whereas diamond drilling yielded intercepts including 4.28 grams per tonne gold, 92.1 grams per tonne silver, 0.44 per cent copper, 5.43 per cent lead and 6.42 per cent zinc over 9.14 metres true width in hole 05-01; 6.89 grams per tonne gold, 112.1 grams per tonne silver, 0.59 per cent copper, 3.56 per cent lead and 4.50 per cent zinc over 7.78 metres true width in hole 05-04; 5.50 grams per tonne gold, 79.5 grams per tonne silver, 0.53 per cent copper, 3.16 per cent lead and 3.84 per cent zinc over 14.6 metres true width in hole 05-05; 7.82 grams per tonne gold, 67.8 grams per tonne silver, 0.64 per cent copper, 4.30 per cent lead and 5.16 per cent zinc over 9.69 metres true width in hole 05-06; 5.07 grams per tonne gold, 51.0 grams per tonne silver, 0.42 per cent copper, 3.89 per cent lead and 5.45 per cent zinc over 8.64 metres true width in hole 05-07 and 3.05 grams per tonne gold, 27.2 grams per tonne silver, 0.35 per cent copper, 2.12 per cent lead and 2.88 per cent zinc over 12.54 metres true width in hole 05-010 (Assessment Report 28208).
Work History
The area has been explored in conjunction with the Samatosum (MINFILE 082M 244) and Rea Gold (Minfile 082M 191) occurrences to the north and northeast, respectively. Exploration in the area began in the late 1800s. To the southwest, exploration for copper, lead, zinc, gold, silver and barite began at the Homestake mine (MINFILE 082M 025) in 1893. Limited production took place from 1926 to 1927, 1935 to 1936 and 1983 to 1984. To the east, the Twin Mountain zone has been explored intermittently since 1936. Exploration focused on massive copper, lead, zinc and barite sulphides.
The discovery of the Rea Gold lenses (MINFILE 082M 191) in 1983 and the Samatosum (MINFILE 082M 244) massive sulphide veins and lenses in 1986 generated renewed interest in the area. In 1983, Kamad Silver Company Limited staked the Kamad claim group and conducted geophysical surveying and minor diamond drilling on the Kamad 7 claim. Additional geophysical surveying was completed the following year and the property was subsequently optioned to Falconbridge Copper. In early 1985, Falconbridge Copper proposed a nine-hole, 2400-metre drill program to test targets on the Rea Gold, Austin-Apex (MINFILE 082M 276) and Kamad options. Two drillholes totalling 300 metres were planned for the Kamad property. Only two of the nine diamond drill holes were completed, neither of which intersected the target horizon, and Falconbridge dropped the option that spring. Sometime later in 1985, 259146 BC Limited drilled five holes totalling 369.7 metres.
In late 1985, the property was optioned to Esso Minerals Canada. In 1986, exploration consisted of an extensive geological, geochemical and geophysical evaluation of the Rea horizon on the Kamad 7 and 8 claims, followed by trenching and 1814 metres of diamond drilling in 11 drillholes. An additional 1125 metres of follow-up diamond drilling was completed the following year. Further work in 1987 focused on the Homestake Bluff area and consisted of geological mapping, soil sampling and 1899 metres of diamond drilling. In 1988, Esso Minerals Canada undertook an extensive exploration program aimed at evaluating all mineral occurrences on the property. That year, 17 NQ diamond drill holes totalling 2094 metres were completed on the Kamad 7 claim. Seven of the drillholes intersected massive sulphide mineralization, resulting in the discovery of a small massive sulphide body known as the K-7 lens.
Homestake Canada Limited acquired Esso Minerals Canada’s interest in the Kamad property in the fall of 1989. That year, Homestake Canada completed 25 drillholes totalling 4972 metres, 15 backhoe trenches totalling 785 metres and 11 kilometres of electromagnetic geophysical surveying on the Kamad 7 and 8 claims.
In 2000, after Homestake Canada Limited allowed the Kamad property to lapse, Paul Watt staked the Extra High property over the northern portion of the Kamad property containing the K-7 showing. That year, Watts completed an orientation soil sampling program with limited prospecting and rock sampling and a soil traverse across favourable stratigraphy. In 2002 and 2003, further programs of prospecting and geological mapping were completed on the Extra High claims.
In 2004, Brinx Ventures Inc. acquired the Extra High property and completed a program of trenching and 18 diamond drill holes, totalling 1874.3 metres, on the property the following year. This work is reported to have indicated good continuity of the mineralization within the K7 lens over a strike length of 175 metres with a fault offset section of the same zone extending an additional 100 metres to the south at a 75-metre lower elevation. Dip lengths extend from surface to 75 metres below surface in the north to central section and from 100 to 150 metres below surface in the southern extension. These dimensions are open at depth and to the south.