The Griz occurrence is located at an elevation of approximately 1700 metres on the south-southeast side of a northeast-trending cirque valley, southwest of the Toodoggone River and approximately 4.0 kilometres southwest of the river’s junction with Bronlund Creek.
Regionally, 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 Paleogene 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 Stuhini Group andesite flows and pyroclastic rocks, and marine sedimentary and volcanic rocks of the Lower to Middle Jurassic Hazelton Group. These 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 calc-alkaline volcanics of the Toodoggone Formation (Hazelton Group).
The dominant structures in the area are steeply dipping faults that 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.
Locally, chlorite-epidote–altered andesite augite-feldspar crystal tuffs, dacite to andesite flows and pyroclastics host a mineralized quartz stockwork and/or breccia structure that trends approximately 155 degrees and dips 70 degrees and contains quartz±calcite veins varying from 0.05 to 1.00 metres in width in a zone 20 metres wide. The veins host minor disseminated to semi-massive pyrite, sphalerite, galena with lesser tetrahedrite and sulphosalts. A quartz monzonite is exposed downslope to the east. The mineralized zone has be traced for 100 to 150 metres along a hematite-altered rock face and in talus and relates to or might be the same mineralized zone traced approximately 600 metres to the south at the Sickle Creek (MINFILE 094E 237) occurrence. Less-mineralized narrow stockwork and shears cut the structure.
In 1999, a sample (DR-8) from a 15-centimetre wide vein of semi-massive sphalerite and galena mineralization assayed 5.78 per cent lead, 14.93 per cent zinc, 2226.1 grams per tonne silver and 7.99 grams per tonne gold, whereas a chip sample (JC99-BK-10), taken approximately 250 metres to the west, yielded 1.2 per cent copper, 1.0 per cent lead, 2.5 per cent zinc, 123.7 grams per tonne silver and 0.73 gram per tonne gold over 1.0 metre (Assessment Report 26252).
In 2003, a chip sample (132940) assayed 4.2 grams per tonne gold, 1943 grams per tonne silver, 0.252 per cent copper, 0.403 per cent lead and 0.919 per cent zinc over 1.0 metre of a 20- to 50-metre wide vein swarm zone, whereas other samples yielded up to 8.0 grams per tonne gold and 2200.0 grams per tonne silver (Assessment Report 27429).
In 2004, assayed wall rock samples from the Griz vein yielded up to 0.72 gram per tonne gold, 307 grams per tonne silver, 0.30 per cent copper, 0.22 per cent lead and 0.08 per cent zinc in drill core, while a surface grab sample from Griz vein massive sulphide material in outcrop assayed 78.8 grams per tonne gold, 2,060 grams per tonne silver, 0.51 per cent copper, 11.4 per cent lead and 10.5 per cent zinc (Assessment Report 27790).
Work History
In 1999, Stealth Minerals staked the initial claims in the area of what is now known as the Sickle-Sofia property and, later that year, Standard Metals conducted a small-scale geochemical program and prospecting on the area as the JC 1-2 claims on behalf of Stealth Minerals. The program discovered quartz and quartz-carbonate veins ranging from 0.5 to 50 centimetres in width with anomalous precious metals values and chalcopyrite, sphalerite and galena mineralization.
Minor follow-up work over the next few years located high-grade silver from a float sample in a talus pile in Griz Bowl.
In 2003, Stealth Minerals completed a program of rock, silt and soil sampling and 78.4 line-kilometres of ground geophysical surveying on the Pine property. This work resulted in the discovery of the Sickle Creek (MINFILE 094E 237) vein to the south of Griz Bowl. Further work late in 2003 located the Griz-Sickle epithermal vein system and the Quartz Lake (MINFILE 094E 301) veins. Also at this time, as part of a private-public partnership with the Geological Survey of Canada and the British Columbia Department of Mines and Energy, the Sickle-Sofia property was included in a multi-parameter helicopter-borne geophysical survey over the Toodoggone district. Several high potassium anomalies and low thorium-potassium ratio anomalies were detected.
In 2004, Stealth Minerals expanded the property package by staking additional claims. A grid-based soil survey was conducted over 27 square kilometres and a total of 728 rock and 2103 soil samples were collected. Also at this time, Stealth Minerals completed 3323 metres of diamond drilling in 24 holes, designed primarily to test downdip and along strike of the Quartz Lake (MINFILE 094E 301 ) A to C veins and test the along-strike projection of the Griz-Sickle (MINFILE 094E 237) vein set.
In 2005, a program of geological mapping and a 21 line-kilometre induced polarization and ground magnetic geophysical survey were completed.
In 2006, Stealth Minerals further expanded the IP/ground magnetic survey by another 21 line-kilometres and expanded the chargeability anomaly a further 600 metres north and 300 metres west. During the 2006 season, a total of 28 rock samples were taken from outcrop and float. Geophysical surveys were completed in the area between and covering the Sofia (MINFILE 094E 238) to Quartz Lake (MINFILE 094E 301) occurences.
In 2015, a program of geophysical review completed for Cazador Resources Ltd. on the Sofia property identified five target areas.
In 2017, Cazador Resources completed 239.0 line-kilometres of airborne magnetic surveying and a 2.5 line-kilometre ground induced polarization survey on the Sofia property.
See Sickle Creek (MINFILE 094E 237) occurrence for further details of the Stealth Minerals Limited Sickle-Sophia property.
