"One of the most important mineral trends of northwestern British Columbia extends from near the town of Stewart north to the Treaty Glacier" - Nelson / Kyba, British Columbia Geological Survery, Ministry of energy and Mines 2014
The Dunwell Mine property lies within this mineral trend located between the Silbak Premier Mine (Ascot) and Red Mountain deposit (feasibility stage – IDM).
The historic Dunwell mine produced 45,657 tonnes averaging 13.3 g/t gold equivalent. Ore remains in the mine and recent drilling has shown potential to develop more reserves of similar grade below the existing mine. Large scale potential exists as multiple ultra-high-grade showings occur along strike (fault) for 3km.
The property boasts excellent logistics with a highway and power running through it and is located only 8km from shipping port in Stewart, BC.
The 1,665 hectare Dunwell property is part of a highly strategic package of mineral claims acquired by American Creek in 2016 which includes the past producing Dunwell Mine (closed in 1941). The Portland Canal valley was the first area to be explored in the Stewart region and is so rich with showings that a checker board of small claim ownership has existed for a better part of a century resulting in a lack of large scale geological work and development. It is evident that large scale potential exists.
Companies started to amalgamate these claims into bigger blocks and through numerous transactions American Creek was able acquire three consolidated properties (Bear River, Dunwell, Silvershot) and add more claims to them in 2018. These contiguous properties, now renamed as The Dunwell Mine Property covers a significant portion of the heavily mineralized Portland Canal Fissure Zone (a zone of faulting and shearing that trends north dips steeply west and hosts a vein system that extends southward for 6.5 kilometres from the Victoria/Dandy occurrence on the north, through the Dunwell mine across Glacier Creek to the Ben Boldt Occurrence).
The majority of production occurred between 1926 and 1937, 45,657 tonnes were produced averaging 6.63 grams per tonne gold, 223.91 grams per tonne silver, 1.83 per cent lead, 4.01 per cent zinc and 0.056 per cent copper (gold equivalent of over 13 g/t or approximately$500/t rock). Potential exists to develop more reserves, along strike to the present workings and at depth below the No. 4 level. Drilling in 2010 has indicated a zone at least 300 metres long and 200 metres along dip with a true thickness of 6-7 metres. Similar to the ore mined, the gold grade of this new extension is probably 5-6 grams/tonne with appreciable silver, zinc, copper and lead.
The Dunwell Mine property is in the richest part of B.C’s Golden Triangle and located just 7km east of the Silbak Premier mine (being put back into production by Ascot) and 11km west of the Red Chris deposit (at feasibility stage by IDM).
The deposit consists of a series of quartz and quartz breccia veins hosted in thin bedded argillite, siltstone and greywacke of the Middle Jurassic Salmon River Formation (Hazelton Group). Andesitic tuffs of the underlying Lower Jurassic Unuk River Formation (Hazelton Group) outcrop to the east of the veins.
Mineralization consists of lenses, disseminations and stringers of pyrite, galena, sphalerite and tetrahedrite with minor chalcopyrite, native silver and argentite in a gangue of quartz and minor calcite. Locally, the Dunwell vein contains up to 75 per cent sulphides. The mineralization is more intense where the veins are intersected by fractures of the West fault zone. High-grade mineralization is contained within one ore shoot in the Dunwell vein. This ore shoot strikes for 30 metres, extends downdip for 150 metres and averages at least 1.2 metres in width. A historic chip sample across 1.14 metres assayed 6.9 grams per tonne gold, 4456 grams per tonne silver, 6.6 per cent lead and 5 per cent zinc (gold equivalent of 2.2 oz/t) (Minister of Mines Annual Report 1933, page 58).
The Dunwell claims are contiguous with the past producing Portland Canal Mine. The Portland mine operated briefly between 1911 and 1912 producing 8,164 tonnes of ore averaging 2.33 g/t gold, 98.55 g/t silver and 1.56% lead. Drilling in 1973 defined a resource of similar tonnage of gold, silver, lead and zinc. BC government Minfile documents (Minfile 103P 064) reports that both mines lie within the Portland Canal Fissure Zone (a 6.5km long shear zone) which has hosted several historic mines that hosted high-grade lead/silver deposits. The much richer Dunwell Mine Property covers the northern half of the Portland Canal Fissure zone which is at a lower elevation (700m) and had greater historic production than the southern half.
Potential Extension of Dunwell Mine
The Dunwell Mine Property contains close to two dozen main showings of high-grade gold, silver, lead, zinc and copper. Of these, over half have been historically explored underground and 7 or 8 have shipped ore, the most significant of which is the Dunwell Mine. Other producing claims within the property had their ore processed at the nearby Dunwell mine. These include the following:
Sunbeam: Approximately 100 tons of ore was high-graded from blasted pits on the exposed Sunbeam vein. A grab sample from the adit dump assayed 4.1 g/t gold, 32.9 g/t silver, 1.35% lead and 4.70% zinc (Assessment Report 10190). The Sunbeam vein varies from 1.0 to 1.8 metres in width, with a definite strike length of 315 metres and possibly up to 588 metres. The Sunbeam vein likely continues northward through the Victoria/Danby occurrence (104A 067) as the Main Reef vein.
George E: At least nine sub-parallel veins spaced 15-40 metres apart with significant mineralization in at least four of them. The Numbers 1, 2 and 4 veins vary from 0.2 to 1.8 metres in width and have been traced along strike for between 165 metres (Number 4) and 300 metres (Numbers 1 and 2). The Number 3 vein varies from 0.1 to 9 metres in width and has been traced for 700 metres.
Mineralization generally consists of disseminated to massive pyrite, galena and sphalerite with a trace of argentite and native silver in a gangue of quartz and minor calcite. A representative sample from a well mineralized lens, 4.6 metres long and 0.05 to 0.46 metres wide in the Number 3 vein assayed 63.1 g/t gold, 137 g/t silver, 5% lead and 6% zinc (Minister of Mines Annual Report 1935, page B23). A 1.5 metre chip sample from the Number 4 vein assayed 17 g/t gold, 583 g/t silver, trace copper, 28% lead and 5% zinc (Minister of Mines Annual Report 1934, page 20). A 1.25 metre chip sample from the Number 1 vein assayed 15.8 g/t gold, 411 g/t silver, trace copper, 7.45 lead and 0.2% zinc (Minister of Mines Annual Report 1937, page B12).
12 tons of high-grade ore was mined from the No. 1 vein with an average grade of 13 g/t gold, 3,250 g/t silver and 23.3% lead.
Little Wonder: Listed as a past producer. Production amount is unknown.
Ben Ali: 5,000 tons yielding 3,000 ounces gold. 4,500 tons at 21.6 g/t gold.
Lakeview: 60 tons grading 4.7 g/t gold, 2,734 g/t silver, and 11.5% lead.
Victoria (Main Reef): Two separate numbers reported; perhaps an initial 6 tonnes of 20.6 g/t gold, 1028.6 g/t silver, 35% lead, and 10% zinc ore was shipped, later totaling 11 tonnes grading 20.15 g/t gold, 775 g/t silver, 25% lead, and 5% zinc.
Mayflower: produced a few tons of ore running about $60 a ton in gold values (1918 values). An adit sample assayed 78.2 g/t gold and 1,961.2 g/t silver.
Silver Ledge: Quartz veins with up to 0.36 ounces per ton gold, 0.04 ounces per ton silver, 5.4% lead and 0.65% zinc.
Emperor: Reported as a past producer – sampling averaged $12 a ton over 20 feet (1925 values).
Goldie: Grab sample from 2 tonnes of clean galena assayed 2,880 g/t silver and 80% lead.
Mimico: Grab samples of galena have assayed up to 5,345 g/t silver and 87.2% lead.
Tyee (Mother Lode): Produced 8.2 tonnes of ore grading 124.4 g/t gold and 4,478.8 g/t silver.
World Class Infrastructure
The Dunwell Mine property may have the best logistics in B.C.’s Golden Triangle. The principal Dunwell workings are about 2km east of the highway and are accessible by four-wheel drive vehicles with travel to the remaining portions of the property by foot.
The property is located approximately 8km north of the shipping terminals in Stewart B.C. with power and Highway #37a running through the western edge of it. It ranges from close to sea level to 700m above sea level making it very accessible even in the winter time for drilling and potential mine reactivation.
Opportunity for processing
Both Ascot (Premier mine) and IDM (Red Chris deposit) have publicly announced intentions to go into production in the near future opening the door for the possibility of deposits like Dunwell to be processed off site. This could dramatically change the feasibility and timeline of the development of the Dunwell Mine.