The Dunwell mine is located 7.5 kilometres northeast of Stewart on the north side of Glacier Creek.

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.

The veins are developed in the Portland Canal Fissure Zone. This zone of faulting and shearing trends north, dips steeply west and hosts a vein system that extends southward for 6.5 kilometres from the Victoria/Dandy occurrence (104A 067) on the north, through the Dunwell mine across Glacier Creek to the Ben Bolt occurrence (103P 080).

The deposit consists primarily of two veins, the Sunbeam (Number 8) vein to the north and the Dunwell (Number 23) vein to the south, with a number of other less important veins. The veins are developed en echelon adjacent to a major north striking, west dipping fault zone (West fault). The veins are commonly situated along one or both sides of parallel lamprophyre dikes which are up to 0.6 metre wide.

The Sunbeam vein strikes 360 to 010 degrees and dips 40 to 60 degrees west. It varies from 1 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.

The Dunwell vein strikes 360 degrees and dips 42 to 50 degrees west. The vein extends along strike for 240 metres and downdip for at least 240 metres, varying in width from 0.3 to 2.1 metres.

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 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 (Minister of Mines Annual Report 1933, page 58).

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.

Early exploration was carried out by the Stewart Mining and Development Company. In 1926, an aerial tramway about 1.6 kilometres long and a concentrating mill of 100 tons daily capacity were constructed. Milling began early in 1921 and ceased later in the same year with the depletion of the then known ore reserves. During 1928 and 1929, some electrical prospecting by the Radiore Company of Canada followed by diamond drilling was carried out with negative results. The property remained inactive until worked by lessees in 1932 and 1933, when small-scale hand operations were conducted. Subsequent to this, more extended leasing operations by individual partnerships and a Stewart syndicate were carried on until the season of 1935, when the property was also operated for four months by the Dunwell Company. In the interval some of the mill machinery was sold to Bralorne Mines, Limited. In 1936, the Welldun Mining, Milling and Power Company, Limited composed mainly of Stewart interests, took a four-year lease on the property. This company reconditioned the mill to a daily milling capacity of 25 tons and operated seasonally until the early winter of 1937.

The area lay dormant until recent years (ca. 1980s) when precious metals improved in price. During 1987, Silver Princess Resources carried out a soil geochemical survey over the northeastern portion of their Dunwell claim group.

In 2010, Mountain Boy Minerals Ltd. made a new discovery at its Dunwell gold mine. A winter diamond drill program was conducted to test the potential for depth extensions of the Dunwell gold-silver mineralization. Highlights include: 6.7 metres grading 14.27 grams per tonne gold, 37.81 grams per tonne silver, 0.25 per cent lead and 0.63 per cent zinc in DDH-2010-9, and 6.64 metres grading 7.66 grams per tonne gold, 37.4 grams per tonne silver, 0.33 per cent lead and 0.90 per cent zinc in DDH-2010-12 (Press Release – May 13, 2010).

During 2017 through 2020, Singer Resources Inc. and American Creek Resources Ltd. completed programs of geochemical sampling, a 13.5 line-kilometre induced polarization survey, a 438.5 line-kilometre airborne magnetic and LiDAR survey and 20 diamond drill holes, totalling 3245.9 metres, on the area as the Dunwell property.

In 2017, two 0.3-metre panel samples (512366 and 512367) from the Middle (#2) adit assayed 13.1 and 21.4 grams per tonne gold with 459 and 189 grams per tonne silver, respectively, whereas five 0.5-metre panel samples (512351 through 512355) taken 40 metres north of the Upper (#1) adit yielded from 6.4 to 11.3 grams per tonne gold with 275 to 1186 grams per tonne silver (McCrea, J.A. [2020-10-20]: Technical Report on the Dunwell Property, Skeena Mining Division, British Columbia, Canada).

The 2019 drill program could not duplicate results reported by Mountain Boy in 2010 and the program indicated that the Dunwell main zone mostly ends above Level No. 4. The holes drilled to test the downdip extension intersected quartz breccias with gold values but no sulphide veins and yielded values up to 9.83 grams per tonne gold and 65.8 grams per tonne silver over 0.35 metre in hole DW19-05 (McCrea, J.A. [2020-10-20]: Technical Report on the Dunwell Property, Skeena Mining Division, British Columbia, Canada). The holes to test for the northern extension of the Dunwell zone returned sulphide intercepts that could correspond to the induced polarization anomaly seen on Line 600 and yielded intercepts of up to 11.35 grams per tonne gold, 142.5 grams per tonne silver, 3.20 per cent lead and 13.07 per cent zinc over 2.69 metres in hole DW19-11 (McCrea, J.A. [2020-10-20]: Technical Report on the Dunwell Property, Skeena Mining Division, British Columbia, Canada). Also at this time, a drillhole (DW19-16) tested a large, induced polarization anomaly under the drill pad and intercepted a massive sulphide zone yielding 8.85 grams per tonne gold, 88.8 grams per tonne silver, 0.22 per cent copper, 1.77 per cent lead and 19.51 per cent zinc over 3.61 metres (McCrea, J.A. [2020-10-20]: Technical Report on the Dunwell Property, Skeena Mining Division, British Columbia, Canada). For a complete summary of drilling intercepts refer to the cited report.