The Tsable River area is separated from the Cumberland section of the Comox coalfield by an area of barren sediments. The Tsable River coalfield is divided into two basins separated by a buried ridge of pre-Cretaceous rocks. The northwest or west portion consists of a broad, northwest trending synclinal basin cut by two northwest trending fault systems. A seam (#2 seam?) ranging from 1.8 to 3.2 metres of predominantly clean coal was mined in this area (Tsable River mine). Some parts of the seam are unworkable due to high numbers of interbedded rock bands. Rock bands are of variable thicknesses. The seam pinches out to the southeast towards the unconformable pre-Cretaceous basement. In addition to the mined seam, four quite distinct seams are present and correlatable.

The mine workings extended 2.4 kilometres down the axis of the syncline and up to 1.2 kilometres along strike. The roof consists of sandy shale and sandstone of the Upper Cretaceous Comox Formation (Nanaimo Group). Discovered in 1945, production began by Canadian Collieries (Dunsmuir), Ltd. in 1946. Production from the Tsable River mine between 1946 and September 1966 was 1,976,817 tonnes of coal. Average contents of the Tsable River coal are 1.20 to 1.70 per cent moisture, 10.72 to 34.58 per cent ash, 29.60 to 36.25 per cent volatile matter, 38.60 to 53.68 per cent fixed carbon, 0.80 to 2.78 per cent sulphur and calorific content of 11,139 to 13,470 BTU per pound (as received basis except for the G.C.V. which is on a dry basis). Canadian Collieries Resources Limited operated the mine from 1947 to 1960 and Comox Mining Company Limited operated from 1960 to 1966. Baynes Sound Coal Mines operated from 1875 to 1877.

The southeast or east basin appears to be heavily faulted and the coal that occurs there has not been mined. Seams of mineable thickness are reported to be present.

The structure consists of gently warped, tilted fault blocks cut by northwest trending normal faults. The strata are folded in the western area by a northwest trending syncline and heavily faulted in the eastern area. A series of east trending faults and oblique, approximately northeast trending faults are also present. Strata generally strikes northwest and dips predominantly northeast at 5 to 7 degrees.

Measured geological resources are 54,996,565 tonnes and indicated resources are 119,936,760 tonnes of high volatile bituminous A rank coal (Coal Assessment Reports 53, 54, 92).

The 1996 Quinsam Coal Corporation and Marubeni Corporation conducted an exploration program south of Tsable River, about 5 kilometres south of the old mine. The drilling program plan was for 7000 metres of drilling in 27 holes. The program succeeded in increasing in-situ reserves in all categories to 38,477,900 tonnes (Information Circular 1997-1, page 24). The reserve lies in a north-easterly trending sedimentary basin on the southeastern side of a prominent palaeotopographic high. The coal in the basin shales out to the south, south of Cougar Smith Creek, but it remains open to the northeast, north of the Tsable River. The company is currently assessing the coal quality; environmental and mine plan studies are in progress. Quinsam Coal Corporation is 63 per cent owned by Hillsborough Resources Ltd. In 1995, Hillsborough created a subsidiary company, T'Sable River Coal Corporation. A decline into the lowermost or No. 1 coal seam, from a site north of Cowie Creek, is planned.

Compliance Energy Corporation acquired the property in 2004 named it the Raven project. They conducted exploration programs in 2006 and 2009. As a result of these programs the company announced updated resource estimates in 2010. Combined measured and indicated resources are 71,998,201 tonnes and inferred resources are 59,430,517 tonnes (News Release April 22, 2010, http://www.complianceenergy.com). Compliance conducted a hydrogeologic study in 2011, including the drilling of wells for installation of peizometers at 7 sites.

A 2011 feasibility study on the Raven project considers an underground room and pillar operation producing 1.93 million tonnes per year (run-of-mine), with an average annual production of 0.85 million tonnes of clean coal per year. The product at Raven would be a semi-soft coking coal (88 percent) and a thermal coal by-product (12 percent). Proven and Probable Reserves at Raven include 29.9 million tonnes, with an estimated mine life of 17 years (Exploration and Mining in British Columbia 2011). The focus of work in 2012 were environmental studies, public consultation, and further feasibility studies, with the goal to advance the project beyond the pre-application phase of Environmental Assessment. In 2013, Compliance Energy Corporation submitted an application for an Environmental Assessment Certificate, however the Environmental Assessment Office determined that the application did not contain all of the required information. Revisions to the application continued through 2014, however Compliance Energy Corporation withdrew the application from the British Columbia Environmental Assessment screening process in March of 2015 (Information Circular 2016-1).