Anthracite in floodplain deposits of the Cretaceous Tantalus Formation is preserved in a west-trending graben on the south side of Mt. Granger, 24 km southwest of Whitehorse. The graben extends from Fish Lake to Double Mountain, a distance of 20 km. Two main seams are exposed by bulldozer trenches across the central part of the Mt. Granger property. The upper seam is about 1.8 m thick at surface and has been traced almost continuously over a strike length of 2 km. The lower seam is at least 3.3 m thick at surface and can be traced for more than 1 km. The seams dip at about 30 to 50 degrees to the north. Rotary drilling in 1985 on the central showing penetrated up to 22.25 m of coal. The best continuous coal intersection was 13.1 m in WC-85-6. Open pittable reserves were calculated at 180,033 tonnes over a 335 m strike length. Six days of mapping in 1987 confirmed the continuity of the two main coal seams which are deformed by open north-plunging folds. A north-trending fault along Fisher Creek cuts off massive conglomerate channel deposits interbedded with the coal in the main showing area against recessive floodplain deposits to the west where up to five coal-bearing horizons occur in a thick shale sequence. Additional reserves may lie beneath the low-lying overburden-covered area west of the Fisher Creek fault.
