The Quintette (Shikano) coal occurrence is located just east of Murray River, about 17 kilometres of Tumbler Ridge.
The region is underlain by an assemblage of sedimentary rocks consisting mainly of continental margin and shelf facies rocks. This assemblage was deposited on and to the west of the Ancestral North American craton. These sedimentary rocks, for the most part typical miogeoclinal facies, range in age from Hadrynian to Upper Cretaceous. Structurally these rocks are part of the Foreland Thrust and Fold Belt of the North American Cordillera.
The coal measures of the region occur mainly in Lower Cretaceous sediments deposited unconformably on older miogeoclinal strata. These sediments were subjected to fold and thrust tectonics which also affected the older rocks.
Approximately 74 per cent of the regional coal reserves are contained in the Lower Cretaceous lower-upper Gates Formation (Fort St. John Group), occurring as eight main seams, A, B, C, D, E, F, G/I and K, from youngest to oldest. In the middle Gates Formation, the upper few seams (D, E, F) are a maximum of 3 metres thick (locally 5 metres) while the lower seams (G/I, J and K) show greatest continuity and seam thickness (seam J is up to 11 metres thick).
The coals are good quality medium volatile coking coals. The basal unit of the Gates Formation (262 to 274 metres), the Torrens member, is overlain by the middle Gates Formation which contains three or four cyclic sequences of coal deposition within 90 metres. This is overlain by the Babcock member and a coal-bearing unit above. Two or three coal cycles (containing seams A, B and C) occur in this sequence, however, the seams are poorly developed with insufficient thickness, quality and continuity to be considered economic. The coals were deposited in a deltaic setting.
The Gates Formation is underlain by the marine Moosebar Formation (Fort St. John Group) and below that the coal-bearing Lower Cretaceous Gething Formation (Bullhead Group). The latter consists of coarse sandstone, carbonaceous shale, coal, sandy shale and conglomerate. Three or four coal zones (closely overlying the basal conglomerate, Middle Coal zone, Bird and Skeeter-Chamberlain zones) are present in some areas but may be poorly developed.
The Skeeter-Chamberlain zone is usually less than 4 metres thick, the Bird seam may be 6 to 7 metres thick (only in the Babcock area) and the Middle Coal zone is not very persistent. It is 6 to 7 metres thick in the Johnston area, and consists of a 25 metre seam with a 1 metre split in the Wolverine River area.
The main structure in the coal-bearing areas are broad synclines and sharper anticlines, separated by low to medium angle thrust faults that dip southwest, with vertical displacements up to approximately 100 metres. Minor thrusts are common.
Sulphur in the Quintette coals is generally less than 0.5 per cent. Local contents up to 0.8 per cent sulphur may occur associated with concentrations of pyrite.
Run-of-mine wet tonnes of metallurgical coal in six seams at Shikano are 10,646,400 tonnes; run-of-mine wet tonnes of thermal coal in six seams total 2,554,800 (Mine Development Assessment Process - Stage I Report, Quintette Coal Limited -Shikano Development, April 1985). Proven reserves at Quintette Trend are 26.1 million tonnes and at Roman, 26.5 million tonnes; all medium volatile coking coal respectively (Open File 1992-1). See Quintette (093P 019) for production statistics. The Shikano pit was mined from 1986 to 1998.
Clean coal reserves, of 12 million tonnes, are contained mainly in the Shikano pit. Exploration in 1995 identified two areas, Mesa Extension (093P 019) and mining along contour at Babcock (093I 011), that would add approximately 19 million tonnes of clean coal to the reserve total (Schroeter, T. and Lane, R., personal communication, 1996).
The original Quintette coal licenses were acquired by Denison Mines Limited in 1969 and 1970. The first coal exploration on the property was undertaken by Denison in 1971. For the purpose of developing the coal licences, Quintette Coal Limited was incorporated in December 1971. A significant exploration program was completed each of the following years to 1977. Smaller programs were conducted in 1979 and 1980. In 1985, the areas at or immediate to the Quintette mine site (093P 019) where Quintette Coal Limited might satisfy long-term production needs, include Wolverine, Marmot Extension, Shikano, and Transfer. In September 1987, production at the newly opened Shikano pit began in earnest complementing that at the Mesa and Wolverine (Frame) (093P 020) pits. Quintette produced approximately 5 million tonnes of metallurgical coal in the calendar year, with about 70 per cent of the production from the Mesa subpits, about 20 per cent from Wolverine (Frame) and 10 per cent from Shikano.