The Nik occurrence, located at the 1976 ND-4 diamond drill hole, is approximately 10 kilometres north of the south end of Johanson Lake (Assessment Report 6452).
The occurrence is near the southern border of an Alaskan-type ultramafic intrusion. This ultramafic is bounded to the southwest by the southwest trending Lay Range fault and to the northeast by a cross fault between the Lay Range fault and the Swannell fault. Across the Swannell fault to the east, lies the para-autochthonous Cassiar Terrane represented by Upper Proterozoic rocks assigned to the Ingenika Group. The ultramafic body intrudes UpperTriassic Takla Group volcanics.
Locally, the area is underlain by Takla Group volcanic rocks which have been intruded by an ultramafic body composed of dunite, peridotite, pyroxenite and hornblendite. A quartz diorite intrusive cuts through the ultramafic body. The south and southeast border of this zoned ultramafic complex, informally named the Wrede Creek ultramafic complex, is in direct contact with hornfelsed volcanics (Assessment Report 15194). The Takla rocks strike east-west and dip moderately to the south. These volcanics consist of massive andesitic, augite-rich, coarse pyroclastics and flows, passing up into fine-grained tuffs and tuffaceous arenites intercalated with argillite and limestone units (Assessment Report 15194). Near the intrusion, these rocks have been hornfelsed to amphibolites.
Mineralization consists of chalcopyrite, pyrrhotite and pyrite in fractures and chalcopyrite and pyrite disseminated in altered zones of peridotite and gabbroic dykes. The altered zones, which contain mineralization, are feldspathic, sericitic, epidotized and silicic (Assessment Report 6015).
BP Minerals conducted regional geochemical exploration surveys of the ‘NIK belt’ during 1973 to 1976. Follow-up surveys on geochemical anomalies led to the discovery of boulders containing high-grade chalcopyrite and molybdenite. A percussion and diamond drill program (3000 metres) was completed over 1977–1979.
The best grades intersected by drilling included 30 metres averaging 0.30 per cent copper in a strongly pyritized and propylitized diorite, and 0.21 per cent copper and 0.025 per cent molybdenum over 70 metres of zeolitized pyroxenite (Property File Rimfire BP Minerals Ltd., 1981).
In 2013, a total of 16 rock samples were taken by Serengeti, 13 in the cirque in the vicinity of the 1976 drilling and 3 along the east-west trending ridge to the north of the 1978 drilling. The maximum copper value sampled was 1.2 per cent copper, 0.185 gram per tonne gold, 9 grams per tonne silver in a strongly altered, magnetic ultramafic talus boulder (Assessment Report 34392). The next four samples returned average 0.17 per cent copper in altered diorite- quartz diorite talus boulders. Prospecting in the Nik target area in the vicinity of the 1978 BP drilling that identified copper and molybdenum mineralization graded 0.2 per cent copper, 0.04 per cent molybdenum from a sample of weathered intrusive float with disseminated pyrite-chalcopyrite along strike of hole NDH-16 (Assessment Report 34392).
WORK HISTORY
The initial wave of exploration in the area led to the discovery of several copper plus/minus molybdenum plus/minus gold porphyry style showings, including the Shred, Nik, and Redgold showings, as well as the adjacent Red and Hat showings. The Nik, Shred and Redgold showings were explored by BP Minerals from 1976-1978 and later in 1986. Exploration included prospecting, soil sampling, trenching, deep overburden drilling, diamond drilling and geophysical surveys. BP carried out property-wide multi-element soil sampling in 1976-77 identifying the Nik and Redgold target areas.
In 1976, BP drilled a fence of 5 diamond drill holes totaling 655 metres. Drilling encountered disseminated and fracture-controlled chalcopyrite and molybdenite hosted in peridodites (of the Wrede Creek Complex) and hornblende-diorites. No assays for these holes were recorded in the assessment records. In 1977 and 1978, BP drilled 2700 metres in 81 percussion holes in the vicinity of the showing. The majority of these holes were drilled to 25-35 metres depth, and they encountered similar lithologies and sulphide mineralization as the 1976 drilling. No assays for the percussion holes were recorded in the assessment records. Also from 1977-1978, BP drilled 13 more diamond drill holes, of which 3 were reported for assessment purposes. Holes NDH-16 and NDH-18 encountered strongly anomalous copper and molybdenum mineralization over significant widths, including 0.18 per cent copper over 54.9 metres in hole NDH-16 and 0.24 per cent copper over 15.2 metres in hole NDH-17 (Assessment Report 7451). In total, 3000 metres of diamond drilling was carried out in 18 holes in the vicinity of the Nik showing.
n 2007, Serengeti Resources Ltd. carried out a geophysical survey over the Fleet claims which included: airborne EM, magnetic, and radiometric surveys over 434 km. The radiometric survey highlighted an area of high potassic/low thorium count in the extreme north of the claim block which could be indicative of potassic alteration. A number of magnetic highs were also outlined which are generally indicative of intrusive bodies. The survey covered the following MINFILE showings:Wrede Creek (094D 009), QUYZVHX (094D 010), Wrede Creek Chromite (094D 026), Red (094D 034) (NIK (094D 109), Shred (094D 111), Fox (094D 156), Hound (094D 157), Hat (094D 158), Midas (094D 159), Fisher (094D 160), Inge (094D 161), Redgold (094D 162), Grapes (094D 163), 04PSC-94 (094D 186). All of these occurrences except Red, Hat, Midas, Grapes and O4PSC-94 were included in Serengeti reporting as being within their Fleet property.
In 2008/2009, a limited induced polarization (IP) and magnetic survey was conducted on the Nik and the Fleet claims on behalf of Serengeti Resources Inc. Although the results on the Nik were complicated by the strike direction three zones of higher chargeability were observed generally trending northwesterly across the lines, while a wide zone trending in the same direction was detected on the Fleet (Airborne Magnetic Survey Maps (Fleet Project), Assessment Report 31136). At the northwest end of the target trend (Nik Showing), in 2008 Serengeti sampled well-mineralized intrusive talus samples (diorite dike material with disseminated chalcopyrite 2-3 percent grading 0.88 per cent copper) and anomalous stream sediment samples (333 parts per million copper in streams), indicating the target may be either open to the northwest or the boulders possibly be sourced from the above target area (Assessment Report 31136). These samples indicated that the geochemical trend is open to the north and northwest.
In 2011 Serengeti completed a work program in the covered valley bottom between the Nik and Redgold target areas that was to a) provide a geological context for the copper-molybdenum mineralization observed in the drilling and soil sampling results, and b) complete Ah soil sampling over the covered IP chargeability anomaly on IP lines L800 E and L1200 E.
In 2013, Serengeti conducted a complete review of existing data and targets in order to cost-effectively plan a comprehensive field program consisting of geochemical and geological surveys (30 rock samples, 51 B-horizon soils, 111 Ah Soils). The program covered areas that include the Nik target, the Redgold target and the valley bottom target area between the two, along the Nik NW linear.
