(SR) 2. Geology
Smoky River Coal Field is situated within the inner foothills of the Canadian Rocky Mountains. The Mine is about 20 km North of Grande Cache town and 360 km West Edmonton, the capital of Alberta (Figure SR1). The coal measure rocks belong to the Gates Formation of the Lower Cretaceous Luscar Group. The Gates Formation is subdivided into 3 members: the Torrens, the Grande Cache and the Mountain Park (Figure SR2).
The Torrens member is a distinct marine sandstone and siltstone about 30 m thick. It is overlain by the Grande Cache member. The latter consists of about 158 m of non-marine siltstones, sandstone, mudstone. In addition, all of the significant coal seams are present in this area. The Mountain park member overlies the Grande Cache member and consists of 155 m to 192 m thick non-marine sandstone, mudstone, siltstone and minor coal seams.
In general, the #4 seam is overlain by shale or cabonaceous shale, which is, in turn, overlain by stronger siltstone and sandstone. In general, roof strata are composed of mudstone and siltstone, which have been extensively sheared by tectonic movement. The structural competence of the units are reduced by periodic fracture zones related to thrust faults. Dr. Peter Cain, CANMET reported the core logging results (for Core # QM9-P3) as follows:
From 0m to 0.65m, recovery 0.65m
Description:
Olive green grey massive mudstone, carbonaceous between 0.23 and 0.30m. There is no distinct bedding but it breaks along preferred horizontal planes with moderate force in the hand along planar, rough, occasional fossiliferous partings. There is one 1 cm thick coal seam at 0.65 m with no break above or below. There is no structural jointing observed.
From 0.65m to 1.48m, recovery 0.83m
Description
Olive green grey massive mudstone is interbedded with frequent medium grey silty to fine grained sandstone and some darker carbonaceous whisps. There is a thin coal parting of 0.5 cm at 1.45 m with no parting plane. There is no distinct bedding but it breaks along the preferred horizontal planes with moderate force in the hand along planar, rough, occasional fossiliferous partings. There is no structural jointing observed. Some of the sandier beds show rusty red coloration (i.e. Fe-staining).
Core breaks at: 0.5, 3.5, 5.5, 4.5, 17.0, 8.5, 7.0,13.5, 4.5, 0.5, 16.5, 22.5, 23.0, 13.0, 4.5 m.
From 1.48m to 3.00m, recovery 1.52m
Description
Olive green grey massive mudstone is frequently interbedded with medium grey silty to fine grained sandstone and occasional carbonaceous whisps. It becomes sandier towards the top, grading to a sandstone with mudstone bands. Sands show Fe-staining at 1.78, 1.86, 2.08, 2.17, 2.35, 2.48, 2.59, 2.68 and 2.46m. There is no distinct bedding but it breaks along the preferred horizontal planes with moderate force in the hand along planar, rough, occasional fossiliferous partings.
Core breaks at: 10.5, 3.5, 2.0, 1.0, 1.0, 77.0, 56.5 m.
(SR) 2.2 Geological Structures
The predominant structure of the coalfield strikes North-West to South-East, comprising thrust sheets containing folded layers of competent sandstone and siltstone units, incompetent mudstone and coal. Dips vary considerably, from horizontal to overturned. The structural environment is either faulted or steeply folded off on the North-East and South-West boundaries of the Mine.
The reserve, at the 5B-4 Mine, is bounded by steeply dipping thrusted zones to the North and South. The major faults are oriented at 110° to 120° azimuth.
The property is dry except for some dripping near the surface and along fault planes, which are assumed to connect to the surface. There is no water encountered in drilling. The inflowing ground water is too low to be measured.
The significant coal seams in this area are numbered from the lower (older) to the upper (younger) formations. These are #4 seam, #8 seam, #10 seam and #11 seam. As regards thickness and coal quality, #8 seam and #11 seam are not significant for economic exploitation. However, the #4 seam is the most significant for mining, which is 3 ~ 5 m (10 ~ 17 feet) thick within the property of 5B-4 Mine (Figure SR3). At the portals, #4 seam dips 6°. Room and Pillar mining is restricted to the areas where strata dip at an angle less than 16° (due to the design limitation of the mining machinery deployed underground).
The #4 seam is, qualitywise, low volatile metallurgical coal. Methane content varies from 1cub.m to 8cub.m depending on depth but generally the coal has a low Methane content. Methane pressure is considered hydrostatic. The saturation level has not been determined.
Figure SR1: Geographic location of Smoky River Coal Limted.
Figure SR2: Generalised stratigraphic column of the Smoky River Coalfield.
Figure SR3: Lithology in the immediate vicinity of #4 Seam in the #5 Mine.
Figure SR4: Site layout of the mining property of the Smoky River Coal Limited.
Figure SR5: Ventilation network scheme in the 5B-4 Mine.
Figure SR6: 5B-4 Mine panel layout.
Figure SR7: Panel development diagram.
Figure SR8: General support system at the 5B-4 Mine.