The GWP (Mount Graves) prospect is located on the eastern side of Mount Graves, 2.75 kilometres south-southeast of Toodoggone Lake and 14 kilometres north of the Shasta occurrence (094E 050) (Assessment Report 19767). Smithers is 290 kilometres to the south.
The GWP prospect 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. Takla volcanics have been intruded by the granodiorite to quartz monzonite Black Lake Suite of Early Jurassic age 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.
Volcanics and volcaniclastics of the Jurassic Hazelton Group are hostrocks of the Mount Graves prospect and surrounding area. These rocks form the eastern limb of a north-northwest trending faulted anticline. Regionally, these rocks have been subdivided into four informal units (Forster, 1984), which at the Mount Graves prospect, dip 50 to 80 degrees to the northeast. Welded and partially welded andesite pumice breccia, overlain by grey, green to orange hornblende porphyritic andesitic flows and pyroxene andesite flows; lesser thin discontinuous lenses of greywacke and laminated siltstone comprise lithologies of the Hazelton Group. Quartz monzonite dikes are found in the faulted core of the regional anticline and along northeast and east-striking faults. A series of quartz feldspar porphyry rhyolitic dikes, striking northwesterly and dipping steeply, occur subparallel to bedding.
Propylitic alteration is pervasive in all units (Forster, 1984). Mafic phenocrysts are altered to chlorite and epidote with hematite and magnetite inclusions or rims. Plagioclase crystals are replaced or rimmed with epidote, chlorite and carbonate. Groundmass is altered to epidote, chlorite, carbonate, sericite and pyrite. Silicification varies from hairline fractures of quartz and calcite to complete quartz flooding along faults and fractures. Pyrite is commonly associated with quartz veining. Weathering products of pyrite include iron oxides, jarosite and manganese oxides along fault and fracture zones. Stockwork and breccia zones consist of quartz, amethystine quartz, chalcedony, calcite, siderite, hematite and barite.
The Mount Graves prospect is composed of two separate but probably related showings; the Upper and Lower GWP zones. These two zones form a wedge-shaped silicified zone 5 to 35 metres wide dipping 55 to 65 degrees to the northeast, in andesite flows.
Forster (1984) has distinguished five stages of mineralization and brecciation. Mineralization within these five stages includes fine grained native gold, native silver, acanthite, pyrite and minor galena, sphalerite and tetrahedrite which occur within stockwork zones consisting of amethystine, white and chalcedonic quartz, calcite, hematite, barite and minor albite. Thin sections have revealed that gold is associated with at least two stages of mineralization; as intergrowths with pyrite or associated with native silver and acanthite.
The Lower zone is hosted in a steeply dipping andesite flow, forming the hangingwall of a 30 metre wide rhyolite dike. The zone is composed of up to 3 per cent fine to medium grained, disseminated pyrite and trace galena. Limonite, jarosite and alunite are present on surface. Mineralization and alteration appear to be controlled by faulting and fracturing subparallel to bedding and do not persist along strike. A little brecciation was noted.
Approximately 125 metres southwest, the Upper zone is a steeply northwesterly dipping, right-lateral fault zone, striking 030 degrees. The zone is at least 30 metres wide. The zone is interbraided with highly variable, multistage silicification, brecciation and mineralization. Pyrite, galena, sphalerite and tetrahedrite are found as blebs, stringers and disseminations in breccia openings. Similar mineralization and alteration were found under 3 metres cover in Trench 4, indicating a probable extension to the southwest.
A total of 28 rock chip and channel samples were taken from the Upper and Lower GWP zones, during property exploration in 1987. The best assay results were from Trench 3 of the Upper zone. Results from sample L-341 were 3.0 grams per tonne gold, 461.6 grams per tonne silver, 1.45 per cent lead and 3.38 per cent zinc (Assessment Report 17326). Sample L-351, from the other end of the trench, analysed 2.1 grams per tonne gold, 503.1 grams per tonne silver, 0.39 per cent lead and 0.24 per cent zinc (Assessment Report 17326). The best results from the Lower zone were from Sample A-665. They were 1.4 grams per tonne gold, 562.8 grams per tonne silver, 0.07 per cent lead and 0.01 per cent zinc (Assessment Report 17326). Resampling of Trench 3, in 1989, yielded 0.34 gram per tonne gold and 171.6 grams per tonne silver over 6.0 metres, including 1.06 grams per tonne gold, 500 grams per tonne silver and 0.117 per cent lead over 1.0 metre, and select grab samples yielded values of up to 6.30 grams per tonne gold, 1628.4 grams per tonne silver, 0.202 per cent copper, 2.348 per cent lead and 2.790 per cent zinc (Assessment Report 19767).
Several other areas of anomalous precious and base metals have been found around the Mount Graves prospect. Three have been explored in more detail and are referred to as the Yellow Rose occurrence, which is located approximately 650 metres to the south at an elevation of 1900 metres, the Orange Rose occurrence, which is located approximately 600 metres to the west- south west at an elevation of 1850 metres and the Vole Peak zone, which is located approximately 350 metres to the south-southwest and between the GWP and Yellow Rose occurrences.
Work History
The Mount Graves property was optioned by Great Western Petroleum Corp. in 1981 and a geological-geochemical field program was conducted on the property between 1981-1983, which resulted in the discovery of the GWP mineral showing which returned values as high as 1.1 per cent gold and 7500 grams per tonne silver in rock samples. (Assessment Report 10050).
Douglas Forster (1984) completed a Master of Science thesis on the southern Toodoggone River area with a comparative economic geology analysis of eight prospects including Mount Graves. Using data from fluid inclusion analysis of mineralized rock from the Mount Graves property, Forster proposed a regional epithermal model that places Mount Graves at a depth favourable for hosting mixed precious and base metal deposition.
In 1984, the area of the gossan zone near Vole Peak, was tested by Newmont Exploration of Canada for possible links of the gossan zone to the GWP Zone. Sampling of trenches yielded up to 12.0 grams per tonne silver over 1.0 metre in trench 3 and 5.2 grams per tonne silver over 7 metres in trench 1 (Assessment Report 13458).
Geostar Mining Corp conducted assessment work in 1985 and in 1986, Yeager and lkona resampled the GWP Zone. Rock grab samples yielded gold values up to 5.82 grams per tonne and silver values up to 5115.37 (Assessment Report 14824). Also investigated was the Yellow Rose zone (a gossan associated with argillic alteration and quartz veining, 550 metres south of the GWP zone). Thirty metres of trenching revealed sparse quartz veining with gold values up to 10.49 grams per tonne gold in a 5 centimetre wide quartz vein (Assessment Report 14824). Lead and zinc values over 1 per cent were also noted.
Work performed Blue Emerald during the 1987 program confirmed the GWP zone as the most promising prospect on the Mount Graves property. Results of trenching and mapping indicate probable extensions to the southwest and northeast. Rock chip sampling on the GWP zone yielded values up to 3 grams per tonne gold, 503 grams per tonne silver, 1.45 per cent lead and 3.38 per cent zinc (Assessment Report 17326). Additional trenching and rock sampling was done on the Yellow Rose zone with indications that similar mineralization may occur on a southeasterly extension.
The 1989 sampling program of Blue Emerald Resources on the Graves 1-2 was concentrated primarily in the areas of the Lake Fault Zone, Yellow Rose Zone, GWP Zone, East Ridge Zone, and Vole Peak (Assessment Report 19767). Work consisted of contour talus-soil sampling, grid soil sampling, prospecting, mapping, and trenching. A total of 199 soil, 58 rock, and 2 heavy mineral samples were collected. A chip sample over 1.5 metres and a rock sample (ER89R009), both from trench 2 on the Vole Peak zone, yielded values up to 29.4 and 54 grams per tonne silver with 0.20 and 1.34 grams per tonne gold, respectively (Assessment Report 19767).
In 1996, Vetta Ventures Corp conducted exploration work on their Jessye 1 to 3 claims that consisted of geological mapping rock sampling, grid work, soil and stream sediment sampling, and Mag-VLF geophysical surveys (Assessment Report 24993. A total of 74 rock and 344 soil samples and 21 stream sediment samples were collected from the property during the 1996 survey. Three promising mineralized areas, the Quartz-filled Breccia Zone, the GWP zone and the Yellow-Rose zone, were located and sampled during the 1996 field work program. The Quartz-filled Breccia zone plots out in the vicinity of the Gravy occurrences (094E 205) which has the same strike and description. A chip sample (J96/R53) of silicified, brecciated porphyritic andesite from a former trench on the GWP zone yielded 1.14 grams per tonne gold, 383.4 grams per tonne silver, 0.110 per cent copper, 0.384 per cent lead and 0.250 per cent zinc over 2 metres (Assessment Report 24993). Also at this time, a rock chip sample (J96/47) collected from trench 2 near Vole Peak yielded 0.870 gram per tonne gold and 17.9 grams per tonne silver over 2 metres (Assessment Report 24993).
In 2003, Stealth Minerals Ltd staked four claim unit (80 units) Sam claims. The Sam claims covered the GWP (Mount Graves)(094E 087), Yellow Rose (094E 203), Gravy (094E 205), Gravy East) (094E 206), TO 2 (094E 212), Duke (094E 218). Stealth minerals undertook a 10 man-day helicopter supported reconnaissance and point specific prospecting and geological evaluation program. A total of 18 rock samples were taken. As part of the regional Government-Private Partnership Toodoggone Initiative, the claims were covered by part of the Fugro operated, Geological Survey of Canada supervised, helicopter airborne magnetic and radiometric survey. The survey recorded 2 magnetic parameters and eight gamma-ray spectrometer parameters flown at a line spacing of 400m and a sensor height of 60 metres during 2003. The survey indicated that the claims are underlain by rocks and alteration permissive to host precious metal deposits. A 1.3 by 1.0 kilometre ThK ratio low occurs within the Sam 3 claim coincident to a potassium high and adjacent to a total field magnetic high. A chip sample (132912) from a former trench on the GWP zone assayed 0.94 gram per tonne gold and 526 grams per tonne silver (Assessment Report 27441). Three other trench samples (132909, 132910 and 132911), taken a few hundred metres to the south and possibly on the Vole Peak zone, yielded from 3.8 to 14.9 grams per tonne silver and trace to 0.24 gram per tonne gold, and a chip sample (132066) from the same area over 2.5 metres of a quartz-breccia zone assayed 16.3 grams per tonne silver and 0.109 per cent lead (Assessment Report 27441).
In 2004, Stealth Minerals conducted geological mapping on the Sam claims at 1:10000. In addition, a total of 11 surface rock samples were taken as float or outcrop samples for analysis. Alteration identification using PIMA spectroscopy was completed on 19 rock samples.
