The GWP (Silver Ridge North) occurrence is located at an elevation of approximately 1800 metres on a ridge approximately 3.5 kilometres south-southwest of Mount Graves.
The area is situated within a Mesozoic volcanic arc assemblage which lies along the eastern margin of the Intermontane Belt, a northwest-trending belt of Paleozoic to Tertiary sediments, volcanics and intrusions bounded to the east by the Omineca Belt and to the west and southwest by the Sustut and Bowser basins. Permian Asitka Group crystalline limestones are the oldest rocks exposed in the region. They are commonly in thrust contact with Upper Triassic Takla Group andesite flows and pyroclastic rocks. These Takla rocks have been intruded by plutons and other bodies of the mainly granodiorite to quartz monzonite Early Jurassic Black Lake Suite and are in turn unconformably overlain by or faulted against Lower Jurassic calcalkaline volcanics of the Toodoggone Formation, Hazelton Group. The dominant structures in the area are steeply dipping faults which define a prominent regional northwest structural fabric trending 140 to 170 degrees. In turn, high angle, northeast-striking faults (approximately 060 degrees) appear to truncate and displace northwest-striking faults. Collectively these faults form a boundary for variably rotated and tilted blocks underlain by monoclinal strata.
The GWP showing area is nearly flat with silicified zones forming rounded hills, and the clay alteration zones forming depressions. Silicified stockwork zones up to 1000 metres long and 20 metres wide strike north-northwesterly within gently dipping andesite tuffs (Forster, 1984) of the Metsantan Member (Bulletin 86). The Metsantan Member is described, regionally, as being composed of trachyandesite flows with lenses of lapilli tuff, and lahar; minor volcanic sandstone and conglomerate (Bulletin 86). Large quartz veins and quartz-sericite veins strike 305 degrees and are up to 60 metres long by 10 metres wide. Some strong clay (argillic) zones parallel to the veins are 5 to 6 metres wide. Barite occurs locally within the quartz veins (Assessment Report 14696).
The stockwork zones contain pyrite, magnetite and barite with minor chalcopyrite and associated malachite. Alteration minerals associated with sulphide mineralization include quartz, calcite, hematite, limonite, kaolinite, montmorillonite and illite.
The alteration, mineralogy, and textural characteristics of the volcanic rocks and mineralized zones are similar to those mineral occurrences on the Silver Pond property (094E 060, 075, 160, 161, 162, 163), although visible gold and silver are not documented on the GWP showing (Forster, 1984).
In 1981, three rock samples (1-F-9307, 1-F-9264 and 1-C-9053) from a major gossanous zone with silicified and argillized volcanic rocks containing pyrite and arsenopyrite with limonite and hematite staining yielded values of 0.365, 0.495 and 0.535 gram per tonne gold, respectively, whereas two other samples (1-E-9783 and 1-F-9296) yielded 0.148 per cent copper and 14.6 grams per tonne silver (Assessment Report 9644). Further chip sampling, later that same year, yielded values of up to 110 grams per tonne silver (sample 1-L-5153; Assessment Report 10049). The gold value for this sample was not reported.
Follow-up property work, in the summer of 1985, was less rewarding. The best results were from Trench 1, a trench that exposed clay, sericite, quartz and limonite in zone of silicified and altered porphyry volcanics. Chip samples yielded 1.6 grams per tonne silver and 0.085 gram per tonne gold over 3.75 metres (84056); and 1.4 grams per tonne silver and 0.10 gram per tonne gold over 1.25 metres (Assessment Report 14696).
In 2003, a grab sample (RMR-PN-03-022) over 1 metre of phyllic-altered monzonite hosting quartz-magnetite veinlets yielded 0.96 gram per tonne gold (Assessment Report 27310).
In 2005, Diamond drilling identified disseminated copper-molybdenum ± gold (lead-zinc-tungsten) porphyry style mineralization hosted by some of the plutonic phases. This has been the main drill target in the nearby NW zone (MINFILE 094E 007). Considerable widths of strongly anomalous lead, zinc and tungsten were also intersected at the GWP (Silver Ridge North) zone. These intersections often coincide with copper-molybdenum mineralization. There appears to be a spatial relationship between lead-zinc-tungsten content and a drillhole’s proximity to the Pillar West fault, suggesting this structure may have played a role in mineralization. The highly altered rocks in these holes and the lead-zinc-tungsten mineralized intrusive rocks may also be evidence of the vertical or lateral zonation of a porphyry system.
Drillhole PN05-03, located on the Silver Ridge North zone, tested a strong gold and silver soil anomaly. The hole intersected a shear zone with 2.0 metres grading 1.47 grams per tonne gold and 57.5 grams per tonne silver (Assessment Report 28083). At increasing depth, the hole intersected zones up to 68 metres wide consisting of strongly altered and pyritic intrusive rocks (halo?) that grade with depth into silicified and brecciated monzonite. A 60.3-metre section near the bottom of the hole contains sporadic, anomalous copper along with values of up to 0.073 per cent lead, 1.17 per cent zinc and 0.026 per cent tungsten were obtained (Assessment Report 28083). It was apparent that PN05-03 intersected Silver Ridge (MINFILE 094E 309) type mineralized structures but unexpectedly bottomed in what appears to be a mineralized porphyry system. Drillhole PN05-08, a 100-metre southerly step out from PN05-03, bottomed in similar, but less extensive, tungsten-zinc mineralization. The halo of altered rocks encountered in both holes and the underlying tungsten-zinc mineralized intrusive rocks may be evidence of a deeper or lateral expression of a porphyry system. Also at this time, two surface chip samples (WGR05-12 and -13), taken to the south and near the drill collars of hole PN05-04 and PN05-05, yielded 0.846 and 0.656 gram per tonne gold over 1.25 and 0.75 metre, respectively, and two nearby quartz vein float samples (GRR05-63 and -64) assayed 2.454 and 2.313 grams per tonne gold, respectively (Assessment Report 28083).
Work History
In 1968, Quebec Cartier Mines completed a program of geological mapping and geochemical (rock and soil) sampling on the area as the Spartan claims.
In 1972, Denison Mines Ltd. completed a program of geological mapping and geochemical (rock, silt and soil) sampling on the area immediately west as the NE, GO and RI claims.
In 1980, Great Western Petroleum Corp. staked the GWP claims to cover the former Spartan claims. The following year, a program of geological mapping and geochemical (rock, silt and soil) sampling was completed.
In 1985, Cassidy Resources Ltd. completed a program prospecting, geological mapping, trenching and rock sampling on the G.W.P. 1 claim.
In 1986, Cyprus Metals Ltd. completed a program of geological mapping and geochemical (rock and silt) sampling on the G.W.P. claims.
During the 1990s through 2015, the area was explored in conjunction with the nearby NW (MINFILE 094E 007) occurrence and a complete exploration history can be found there.
