Eskay Mining Corp. (“Eskay” or the “Company”) (TSX-V:ESK) (OTC-PK: ESKYF) (Frankfurt: KN7; WKN: A0YDPM) is pleased to announce an update to its ongoing targeting efforts for the 2018 exploration season. Further to its March 5, 2018 news release highlighting interpretations and exploration strategies for the Red Lightning and TV-Jeff zones (see http://eskaymining.com/index.
Figure 1: Eskay Mining Corp.’s property with highlighted exploration targets (red stars), and nearby mines and exploration plays.
Big Red Zone
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While the Big Red zone has been known for some time as an exploration target, it was largely ice- and snow-covered until recently, and its true potential as a large-scale porphyry-style target only emerged during the present review. In the early 2010’s, retreating ice on the southeast flank of Unuk Finger revealed a deep red gossan that extends for over 1 km north-south and across several drainages. Prospecting in and around the gossan over the intervening years has returned highly anomalous Cu, Au, Ag and Mo values, with 61 grab samples averaging 0.11% Cu, 0.058 g/t Au, 1.8 g/t Ag and 0.035% Mo (Figure 2). In particular, a cluster of three intensely quartz-sericite-pyrite (QSP) altered samples collected from a gossanous knoll near the northern end of the trend averaged 0.27% Cu, 0.090 g/t Au and 4.3 g/t Ag, with the best sample yielding 0.68% Cu, 0.124 g/t Au and 6.2 g/t Ag.
Figure 2: Aerial image of Big Red Zone, with rock and stream sediment samples highlighting Cu values.
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Limited geological data has been collected from the Big Red zone, but work in 2016 by the Company, along with regional mapping in the early 1990’s by the Mineral Deposit Research Unit at the University of British Columbia indicates that the Big Red zone occurs near the eastern contact of the Tertiary Lee Brant pluton, which intrudes Upper Triassic to Lower Jurassic stratified rocks (Figure 3). Previous work by the Company has also identified a smaller northerly elongate intrusive body of unknown age in this area, as is shown in fig. 3.
Figure 3: Geology of the Big Red zone (after Lewis et al, 2003) showing Cu anomalous grab samples.
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In 2006, an airborne geophysical survey (EM and magnetics) was flown by the Company along the trend which included Big Red, and it outlined a near-surface conductivity (EM) anomaly within an area of low total magnetic intensity that coincides directly with the anomalous surface samples (Figures 4, 5). This represents an excellent exploration target, with the magnetic low possibly explained by magnetite-destructive QSP alteration associated with an underlying porphyry system. Another expression of such a system may be the nearby northerly-trending intrusion of uncertain age. The EM response is interpreted to be the result of a conductive, sulfide-mineralized vein stockwork present at surface and may be an indication that the veins and sulphide system are continuous to depth. Surface samples collected from the Big Red zone indicate that host rocks are largely volcanic, which likely rules out the possibility that the EM anomaly is a result of conductive, graphitic sedimentary rocks.
Figure 4: Big Red zone with rock samples and EM (ZOff) conductivity anomalies (pink = high, blue = Low).
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Figure 5: Big Red zone with rock samples and Total Magnetic Intensity (pink = high, blue = low).
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One feature that is particularly notable about the Big Red porphyry system is that it lies directly along trend to the southwest from the nearby, world-class Au-Cu-Mo-Ag porphyry deposits in the Sulphurets Camp, which are all associated with Early Jurassic intrusive rocks. Also of interest is the fact that several grab samples from the Big Red zone yielded highly anomalous tungsten values (five samples ranging between 1190 to 4790 ppm). While tungsten is not a significant component of the mineralization in the other Sulphurets Camp porphyry deposits, it does appear to be associated with Early Jurassic intrusive rocks farther to the south, near Hyder, where the Texas Creek pluton hosts scheelite-bearing veins that are cut by younger Tertiary intrusive rocks similar in age to the Lee Brant pluton (see https://pubs.usgs.gov/bul/
Work planned for this season at Big Red includes additional detailed geological mapping, with a focus on delineating zones of mineralization and alteration. This should provide an improved framework for understanding and interpreting the nature and distribution of porphyry-style mineralization. It should also help to place the mineralization within the context of what is clearly becoming a well-established regional southwest-northeast trend of Au-rich porphyry centers, from Copper Belle on the northeast, south-southwesterly through Iron Cap, Mitchell-Snowfield, Sulphurets, Kerr, and now, perhaps, to Big Red (fig. 1). In addition to geological mapping, an IP survey over the known EM anomaly has been recommended and is being planned to help outline zones of chargeability and to provide increased confidence in targeting drilling.
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