The Portland Canal mine is located 3 kilometres south of Glacier Creek, 6 kilometres northeast of Stewart. The mine was briefly in operation between 1911 and 1912.

The deposit is hosted in thin-bedded argillite, siltstone and limestone of the Middle Jurassic Salmon River Formation (Hazelton Group). These sediments strike 160 degrees, dip 20 to 90 degrees west and are intruded to the southeast by a Tertiary(?) augite diorite stock (Coast Plutonic Complex).

The deposit is 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) in the north, through the Dunwell mine across Glacier Creek to the Ben Bolt occurrence (103P 080) in the south.

The deposit consists of a quartz breccia vein striking 155 degrees and dipping 30 degrees west in argillite. The vein, up to 10 metres wide with an average width of 2.4 metres, has been traced along strike for 600 metres. The vein is cut by several vertical shear zones which strike 169 degrees. Several parallel hornblende diorite dikes closely follow the vein.

Mineralization consists of lenses of massive pyrite, tetrahedrite, galena, sphalerite and minor chalcopyrite, arsenopyrite and argentite. The mineralization is concentrated in two flat lying, pod-shaped ore shoots from 0.6 to 3.0 metres wide (average 1.5 metres in width). The shoots extend along strike for up to 49 metres and downdip for up to 73 metres.

Drilling in 1973 defined a reserve of 11,160 tonnes grading 2.23 grams per tonne gold, 208.8 grams per tonne silver, 1.58 per cent lead and 1.87 per cent zinc over a strike length of 58 metres, dip length of 37 metres and an average width of 1.6 metres (Assessment Report 4935, pages 1,8,9).

A branch vein (the Gipsy vein) on the north end of the main vein, strikes 050 to 074 degrees for 60 metres and dips 60 to 70 degrees southeast. The vein varies from a few centimetres to a metre in width and is adjacent to a parallel feldspar porphyritic dike. Mineralization consists of pyrite, galena, sphalerite and minor arsenopyrite and chalcopyrite. A 0.91 metre chip sample across this vein assayed 41.1 grams per tonne gold, 185 grams per tonne silver and 5 per cent lead (Minister of Mines Annual Report 1909, page 61).

Production from the Portland Canal mine totalled 8164 tonnes of ore with an average grade of 2.33 grams per tonne gold, 98.55 grams per tonne silver and 1.56 per cent lead.

The mine workings are at an elevation of about 731 metres above sea level and consist of three tunnels with connecting raises. In 1910, the lowest or No. 3 tunnel, is the working tunnel. This tunnel is in 152 metres and follows the vein. From this level a raise has been put up to the No. 2 tunnel. The No. 2 tunnel is about 16 metres vertically higher than No. 3, the vein dipping at an angle of about 30 degrees, and is in 61 metres with a raise put up to the No. 1 tunnel. At about 7.6 metres in from the portal the tunnel entered on pay ore in which it has continued to the face. The No. 1 tunnel is about 12 metres higher than No. 2, and has been driven about 55 metres with pay ore for its entire length. At one point in the drifting, the tunnel was deflected to the right and ran out of the ore shoot but when brought back to the original course, picked up the ore again.