The Red Tusk is a precious metal VMS project that is situated in southwestern B.C., approximately 12 km west of the town of Squamish. The co-ordinates of the property’s geographic centre are 477,736 m E, 5,513,405 m N (UTM NAD’83, Zone
The Red Tusk project is located east of Silver Tusk Creek, a south- flowing tributary of Red Tusk Creek, at an elevation of approximately 1080 metres.
A similar pendant to the southeast hosts the Britannia Noranda/Kuroko-style massive sulphide deposit which produced 47.8 million tonnes grading 1.1% Cu, 0.65% Zn, 6.8 gm/t Ag and 0.6 gm/t Au during a 62 year mine life. The Britannia orebodies were formed from hydrothermal solutions genetically related to dacitic volcanism.
The Red Tusk is also noted as one of the mineral occurrences in BC which exhibit some of the characteristics of the famous Eskay Creek-Type of Deposits.
The occurrence is underlain by a series of marine sediments and volcanics in a relatively undisturbed sequence of north to northwest- trending and moderately to steeply west- dipping units. Stratigraphic tops also face west. The sedimentary units are composed of cherts and argillites and do not constitute a large portion of the stratigraphy volumetrically, but are important as marker horizons. The volcanic rocks are variable in composition and include basalts, dacites, rhyodacites, rhyolites, massive andesite porphyries and laminated tuffs, and a distinctive fragmental unit. Late mafic dykes cut the stratified sequence and usually strike northeast and dip vertically. Some folding is evident and faulting is randomly distributed, with little or no movement. An altered siliceous horizon trends north across the property and is comprised of a light- grey to grey massive, aphanitic, siliceous, rhyolitic unit with a characteristic chalky white weathering. Prominent foliation and shearing accompanied by quartz veining is present along the entire length of the unit. Intermediate to felsic volcanics occupy the central portion of the property. The rocks are dacite to rhyodacite in composition and include flows, gritty lapilli tuffs and finely laminated ash tuffs. A fragmental volcanic rock unit
(polymictic volcanic breccia) occurs and is composed of crowded, angular to sub-angular, mixed pebble to cobblesized clasts of tuffs, flows, chert and argillite in a fine-grained, dusty matrix. This unit generally overlies two thin units of andesite agglomerate and tuff, which in turn overlies andesite flows.
Mineralization on the Red Tusk property is associated with the altered siliceous rhyolite horizon. The South, North and North Extension zones occur within this unit.
Locally, a siliceous rhyolite unit hosts sulphide mineralization. Some sericitic alteration of the rhyolite has left it with a greenish cast. Mineralization consists of disseminated and veined pyrite, sphalerite and galena with
pyrrhotite and chalcopyrite.
The Red Tusk is a volcanogenic massive sulphide prospect in rocks similar to and along strike from the former Britannia Mine at Britannia Beach. Precious and base metal mineralization is associated with altered rhyolitic rocks exposed over a strike length of two kilometres. Portions of the mineralization, including the North Zone Extension, discovered in 1988, have not been adequately explored. The geochemistry of local stream sediments reflects the occurrence of copper, zinc and leads sulphides, and demonstrates high potential for finding new mineralized zones to the north.
The Red Tusk property is located approximately 65 kilometres northwest of Vancouver, British Columbia in the Tantalus Mountain Range. The closest communities are Sechelt, 45 kilometres to the southwest and Squamish, 14 kilometres to the southeast. The property is ocean accessible via barge or water taxi to Clowhom Falls, at the head of Salmon Inlet and thence by a network of logging roads that access various portions of the project area. Alternative access can be gained by helicopter from Squamish, Sechelt, or Vancouver. The project encompasses a portion of the Clowhom Pendant, an elongate pendant of Cretaceous Gambier Group volcanic and sedimentary rock within the Cenozoic-Mesozoic Coast Plutonic Complex. The Gambier Group is comprised of andesite to rhyolite flows and pyroclastics, greenstone, argillite, minor conglomerate, limestone, and schist.
Mineralization on the property was described in detail by Chung (1988). The precious metals prospect comprises five zones. The South, North and North Extension zones are associated with an altered siliceous rhyolite horizon, 30-100 m wide and 2 km long, within a series of differentiated volcanics.
The Mavis and Cirque zones are hosted by a different geological assemblage and the mineralization indicates a base metal potential rather than a precious metals prospect. In the South zone several sub-parallel northerly trending faults apparently offset and repeat a mineralized exhalative which comprises altered, bleached siliceous flows with quartz micro-veining.
From the Cirque massive sulphide zone high grade copper, lead, and zinc values were obtained from a 17 meter long trench. Sixteen chip panel samples were taken from the trench with values ranging from 0.4 to 1.3% copper, .02 to 5.8% zinc and .007 to 1.54% lead, (values converted from ppm). A grab sample taken from this zone has yielded 7.1 % copper, .8% lead, .9% zinc, and 3.5 oz/ton of silver and .05 oz/ton of gold. The mineralized zone is approximately 30 meters wide and to date has been traced visually for over 250 meters.
Phase One results included a float sample of barite from the North zone assaying .67 oz/ton of gold and a chip sample from the Mavis massive sulphide zone which contained 2.97% copper, .4% lead, 1.29% zinc, arid 2.01 oz/ton of silver over a 1.5 meter width. Three zones have been identified as containing considerable massive sulphide mineralization: the Mavis, Mavis Lake, and Cirque zones. In addition, sampling of the exhalite rock unit over a 2.5 kilometer strike length has returned anomalous gold values over its -length and contains three high grade precious metal zones called the North , South , and Silver Spider zones.
Prospecting and sampling along of the exhalite unit has uncovered a steeply dipping highly mineralized zone 8 meters wide by 100 meters long.
The zone known as the "Silver Spider Zone", disappears under vegetation at both ends with a possible extension uncovered some 250 meters upslope. A total of 34 samples were taken over the Silver Spider zone.
Trenching on the Cirque Zone produced base and precious metal concentrations as high as 1.47% Cu, 1.74% Pb, 7.63% Zn, 2.25 oz/ton Ag and 0.012 oz/ton Au. Higher values were obtained from float whose source was inferred to be from higher elevations in the zone (Chung, 1988).
Although further investigation of the South, Cirque and North Extension Zones were recommended, Schellex did not return to the area.
The nearby past producing Britannia Mine is located in a similar geologic pendant environment, the Britannia Pendant. Locally the property is underlain by andesitic flows and pyroclastic units to the northeast, and various phases of diorite to the southwest.
Sandwiched between these two main lithologies and encompassing the South, North and North Extension zones are felsic volcanic rocks ranging from dacite to rhyolite and a siliceous gold bearing exhalite unit.
The felsic volcanic rocks include flows and various pyroclastic units. The exhalite unit is very finegrained to aphanitic, massive, tough and siliceous and is locally pale green coloured where sericite altered to bleached white.
Two main styles of mineralization are being sought:
(1) Precious metal mineralization associated with felsic volcanics and a felsic exhalative horizon such as that seen at the South, North, and North Extension zones; and semi-massive to massive base metal mineralization with precious metal credits in andesitic to rhyolitic volcanics as seen at the Mavis and Cirque zones.
(2) The exhalite / altered siliceous rhyolite horizon has been traced for a distance of approximately two kilometres (Chung, P.L., 1988). Anomalous gold and silver values from the Silver Spider zone, a portion of the North zone, include a grab sample of barite rich siliceous rhyolite that assayed 0.466 oz/ton gold, 166.12 oz/ton silver, 20.06%
zinc, 17.89% lead and 0.12% copper.
Results from a 17 metres long trench excavated on the Cirque zone included assays up to 1.47% copper, 1.74% lead, 7.63% zinc, 2.25 oz/t ton silver and 0.12 oz/ton gold
A Third Style of mineralization was noted by J.W. Laird, 1982 which is described as an 18 metres wide quartz-carbonate sulphide-bearing vein developed at the contact of the Gambier Group pendant and the Coast Plutonic Complex. The vein returned anomalous base and precious metals values and is reported to lie at the contact between chloritized diorite and hornfelsed tuffaceous andesite.
The style of mineralization on the Red Tusk property bears similarities to volcanogenic massive sulphide (VMS) deposits such as the nearby past producing Britannia Mine. The properties are geologically similar as is the nature of the mineralization, as indicated by lead isotope ratios. One sample of galena from bariterich material from the Red Tusk Project was analysed for lead isotope composition, the ratios plot favourably with data from the past producing Britannia Mine indicating the metals came from a common or similar source.
Gold distribution at the Britannia Mine is best developed in a laterally extensive exhalite horizon and in a siliceous goldcopper zone in felsic breccias and tuffs proximal to exhalite mineralization (Britannia Study Group, 1990; Spencer, B.E. 1990). The Red Tusk VMS deposit also has an auriferous extensive exhalite horizon.
Historical production from the Britannia Mine totaled approximately 48 million tonnes at an average grade of 1.1% copper, 0.7% zinc, and 0.1% lead. Recovered gold and silver indicate grades of 3.81 g/t silver and 0.32 g/t gold. Britannia was discovered in 1888, began production in 1905, and after nearly 70 years of underground operation produced more copper than any other mine in British Columbia.
At one time it was the largest copper mine in the British Empire. Britannia survived the Great Depression, labour shortages brought on by two world wars, and several natural disasters. For most of its life Britannia was owned by the Howe Sound Company of New York, which was formed in 1903 for the purpose of financing the development of the mine. In 1963 it was purchased by Anaconda Canada Limited, which operated the mine until closure in 1974.