Brynnor Mine, Alberni Mining Division, Vancouver Island, British Columbia, Canadai

Regional Level Types
Brynnor Mine	Mine
Alberni Mining Division	Division
Vancouver Island	Island
British Columbia	Province
Canada	Country

The Brynnor past producer is located on Draw Creek, approximately 3.4 kilometres north of Maggie Lake.

The deposit occurs within a sequence of limestone and tuff of the Upper Triassic Quatsino Formation (Vancouver Group). These are cut off to the south by a large quartz diorite stock of the Early to Middle Jurassic Island Plutonic Suite. The sequence has been intruded by Tertiary syenite porphyry and diorite dikes, and is in fault contact with andesite of the Lower Jurassic Bonanza Group.

The tuffs show partial alteration to sericite, epidote, chlorite, and serpentine in thin-section while the limestones are commonly only recrystallized. The skarn mineralization is predominantly garnet-epidote alteration of the tuffs which envelopes the pods of magnetite for thicknesses up to about ten metres. Skarn minerals are not disseminated within the magnetite or the surrounding limestone and tuff beyond the alteration envelope. However, many dioritic dikes are partially or completely altered to skarn.

Structurally, the deposit has been folded and faulted. Fault offsets are generally small and of short areal extent. The layers of limestone and tuff have been folded into a broad anticline which plunges at a low angle to the southwest. Folding and most faulting precede the mineralizing events.

The magnetite is quite pure, containing only trace amounts of calcite, pyrite, and pyrrhotite. It appears to be the product of late stage mineralization as evidenced by the purity and cross- cutting relationships. Two large mineralized pods lie along the contact between the limestone and tuff. Small, isolated pods are found scattered within the tuffs, but are of no economic consequence. Magnetite and skarn are preferentially located where dikes cross the limestone-tuff contact but no magnetite is found within the dikes.

The main magnetite body has been mined by open pit. The other body lies east southeast of the old pit and has been outlined by diamond drilling and underground development. A fault separating the two bodies strikes north northeast and dips 70 degrees west. In the eastern body, the massive magnetite appears to be bounded by fault slips and gouge zones. This ore body is 60 metres deeper than the open pit body.

From 1962 to 1968, the open pit produced concentrate containing an average of 63.8 per cent iron. A total of 3,011,306,260 kilograms of iron concentrates was shipped from 4,480,940 tonnes mined. Reserves for the east ore body are undocumented, however, they likely contain a grade comparable (56 per cent) to the deposit mined at the open pit.

In 1988, two 13.6 kilogram bulk samples of waste rock were analyzed for associated alloying element content. Results were negligible (Assessment Report 18150).

In 2008, Ridgemont Capital Corp. completed 21 diamond drill holes, totalling 6678 metres, on the occurrence.