The Dunlevy (Williston) occurrence is located north of Williston Lake, approximately 90 kilometres west of Fort St. John or 37 kilometres northwest of the community of Hudson's Hope, in the Liard Mining Division.
The Peace River Coalfield extends nearly 400 kilometres along the Northern Rocky Mountain inner foothills from the Alberta border, 180 kilometres east of Prince George, to 130 kilometres north of Hudson’s Hope at Pink Mountain. Medium to low volatile bituminous coal seams of economic thickness and continuity are hosted by the Lower Cretaceous Gething (up to 1036 metres thick) and Gates (up to 280 metres thick) sedimentary formations of the Bullhead and Fort St. John groups, respectively. The Gething Formation represents the dominant coal-bearing strata north of the Sukunka-Bullmoose area (MINFILE 093P 001, 093P 014) west of Tumbler Ridge.
At the Williston occurrence, one main coal seam, the lowermost Gething seam, and a large number of thinner coal seams, most less than 1.0 metre thick, occur in the Lower Cretaceous Gething Formation (Bullhead Group). At this location, the formation is less than 300 metres thick and consists of sandstone, shale, siltstone, mudstone and minor conglomerate. It is deposited in well-developed cyclothems, which range in intervals from 1.5 to 7.5 metres in thickness. A typical cyclic order of deposition consists of: dark grey mudstones and shales; shale and siltstones with sandstone interbeds; very fine to medium-grained sandstones; silty, sandy mudstones and argillaceous silty sandstone; lithified seat earths; black soft mudstones; and black fissile carbonaceous shale.
A few thin and discontinuous coal seams occur in the Upper Jurassic to Lower Cretaceous Minnes Group. The regional structure trends northwest.
The structure in the West Block consists of the Central Dunlevy syncline, which is flanked to the east and west by the Butler-Portage and Gething-Stott structural zones, respectively. The structure is relatively simple within the property boundaries (i.e., in the Dunlevy syncline); however, subsidiary folds and faults associated with the more deformed zones to the west and east are probably present.
In 1981, sampling indicated the coal is all of high volatile bituminous C rank. Two samples from a seam, intersected at 22.5 to 25.6 metres in drillhole W1MH 81-11, contain 25.8 to 69.7 per cent ash, 11.4 to 19.4 per cent volatile matter, 16.2 to 52.9 per cent fixed carbon and 0.23 to 0.59 per cent sulphur on an air-dried basis and dried basis (Coal Assessment Report 688).
The Williston area was first explored in detail by Utah Mines Limited in the 1970s. This included the search for large reserves of metallurgical coal in the land north from Williston Lake along the Dunlevy syncline, past the Chowade River. In the Dunlevy Creek area, only one drillhole was drilled to a depth of 246 metres. This hole was abandoned before entering the bottom Gething-Dresser contact and cut 41 thin coal seams. In 1971, the area along the east slope of Butler Ridge was obtained by Amax Coal Company. They drilled four holes north of Ruddy Creek to depths of approximately 365 metres. Several coal seams were intersected with a few in the order of 1 to 1.5 metres.
By the early 1980s, the Williston area was being explored by Cyprus Anvil Mining Corporation and Hudson's Bay Oil and Gas Company Limited. In 1981, a regional mapping program and 11 diamond drill holes, totalling 1684.7 metres, were completed on the property. Three holes within the East block of licenses (MINFILE 094B 024) did not penetrate through the top of the Gething Formation, and no coal seams were intersected. In the West block of licenses, a 3.0-metre coal and shale interval was intersected in the middle of the Gething Formation, at a depth of 22.5 metres.
Exploration programs identified four potential areas, totalling a possible 35 million tonnes of clean coal. The largest area, south of Dunlevy Lake, had a possible regional reserve of 15 million tonnes; a possible 5 million tonnes was identified from the area on the west slope of Butler Ridge; another possible 5 million tonnes was identified from the Trojan seam on the east side of Butler Ridge; and a further 10 million tonnes was identified from syncline and anticline structures to the east of Butler Ridge (Property File - Cyprus Anvil, J. Loader, 1980).
In December 2010, the Government of British Columbia committed to develop a plan to manage the seven northern ecotype caribou in the South Peace River area. One project undertaken to assist development of the Peace Northern Caribou Plan was a modelling exercise to develop alternate development scenarios. This project integrated the available scientific information and expert opinion to predict the future abundance of caribou. It predicted future caribou numbers based on projections of industrial build-out by the coal, forestry, wind and oil and gas sectors. The report from this project, entitled "South Peace Northern Caribou Management Model", was completed in 2012 and is available at https://www.env.gov.bc.ca/wld/speciesconservation/nc/documents/Final_Wilson%20%202012%20%20PNCP%20management%20model.pdf.
NWP Coal Canada Ltd, a subsidiary of Jameson Resources Limited, continued exploration and development of the Peace River coal projects: Dunlevy, Graham River, Peace Reach and Carbon East. During 2013, NWP focused on Dunlevy, refining tenure boundaries and advancing geological models. The company was issued coal licenses late in 2013 and planned to proceed with a two-stage drilling program on the western limb of the Dunlevy syncline in 2014. In 2014, Dunlevy Energy Inc., a subsidiary of Jameson Resources Ltd., drilled on the western limb of the Dunlevy syncline at their Dunlevy property on the north side of Williston Lake.
In 2014, Dunlevy Energy Incorporated (a wholly owned subsidiary of Jameson Resource Limited) completed 13 drillholes, totalling 1302 metres, in a previously undrilled area approximately 4 kilometres northwest of the area explored in 1981. All of the 2014 drillholes intersected portions of the Gething Formation, with most drillholes intersecting multiple coal seams of variable thickness up to 3.56 metres. Four drillholes were twinned to obtain core samples of target coal seams for coal quality analysis. Laboratory results indicate that the coal exhibits relatively high recoveries (ranging up to 81 per cent on the +0.25-millimetre fraction) with relatively low ash content. Petrographic and washability tests indicate the coal product at Dunlevy to be a high volatile bituminous A rank coal (Press Release, Jameson Resources Limited, October 17, 2014).