At least 3 coal zones are present in the Suquash area. The zones may be up to 3 to 4 metres thick, with clean coal thicknesses rarely greater than 1 metre. Numerous thin (less than 1 metre), non-persistent coal bands are present in addition to the coal zones. The thicker coal zones contain considerable quantities of mudstone bands. All the seams pinch and thin to the northwest, while thickening especially in the lower zones occurs to the southeast. The number of thin coal bands also increases to the southeast.
The No. 3 coal zone has most potential, with the best intersection being 3.31 metres of which 1.61 metres is clean coal. Shale and rock bands and partings are common and up to 0.5 metre thick. The coal is high volatile bituminous "C" and contains on average 5.98 per cent moisture, 45.34 per cent ash, 23.31 per cent volatile matter, 25.38 per cent fixed carbon and 2.21 per cent sulphur with a calorific content of 5969 BTU per pound as received basis with shale partings included. The coal is interbedded with predominantly sandstone and shale.
The area with most potential is northeast of Misty Lake and south-southeast of Single Tree Point, and to the east and southeast under the sea (1980).
The structure of the Basin appears to be a broad northeast trending, gently northeast pitching syncline. Dips are low, generally less than 10 degrees. A number of minor folds occur with axes parallel to the main fold. The basin is confined to the southwest by a major northwest trending normal fault which is downthrown to the northeast (displacement 244 metres to 305 metres). The basin is also cut by a series of north and northeast trending faults.
Mining took place primarily in the early 1900's (Pacific Coast Coal Mines Ltd.) at the Suquash mine. Dr. W.F. Tolmie recognized this area as the first Coal found on Vancouver Island in 1835. Dawson (1886) reports 9,000 to 11,000 tonnes of coal produced by the Hudson's Bay Company from 1849 to 1853. To the west and south of the mine the coal seam mined thins to less than 1 metre. Mineable thicknesses of coal at this horizon are expected under the sea to the south and east or northeast of the old mine. Pacific Coast Coal Mines Limited mined the area from 1908 to 1914. Brief work was done from 1920 to 1922. Suquash Collieries Limited conducted operations in 1952.
In 2008, Electra Gold Ltd. completed an exploration program including four diamond drill holes, totalling 672.36 metres, with geophysical logging by Century Wireline Services. All of the 4 drill holes intersected the targeted No. 2 seam, encountering interbedded coal and rock partings ranging in gross thickness between 0.2 to 2.42 metres. According to Cathyl-Bickford (Coal Assessment Report 1007), core and hand specimens are normally-banded, moderately-bright, blocky, humic bituminous coal, with well-developed cleats. Parting materials comprise variably carbonaceous, root-penetrated mudstone and siltstone, and (less-commonly) fine-grained kaolinitic sandstone.
Inclusive of associated rock partings, Measured and Indicated Resources of immediate and future interest at Suquash include 4.823 million tonnes of high volatile B to high volatile C bituminous rank coal (Coal Assessment Report 1007).
