Coal Drilling at Trail Mountain, North Horn Mountain, and Johns Peak Areas, Wasatch Plateau, Utah (B-112)

ABSTRACT The drilling of seven core holes by the Utah Geological and Mineral Survey was done under contract with the United States Geological Survey. An eighth hole was planned but was abandoned because of environmental considerations. The total footage drilled was 4,590.4 feet and included 1,935.4 feet of coring. The depth of the holes ranged from 276.4 feet to 1,158.3 feet. Drilling was mostly in the Blackhawk Formation, a coal-bearing unit of the Mesaverde Group of Late Cretaceous age; and in each hole the upper few feet of the underlying Star Point Sandstone were intersected. All but one hole intersected at least one coal bed 4 feet or thicker, the thickest being 9.3 feet. Three areas were investigated, Trail Mountain, North Horn Mountain, and Johns Peak. At Trail Mountain the Hiawatha bed ranges in thickness from 4.5 to 9.3 feet and averages a little over 7 feet. Only in one hole was more than one minable seam found. One hole was drilled in western North Horn Mountain, but no thick coal bed was intersected. The important coal bed penetrated in the Johns Peak area is thought to be the upper Ivie and is 4 to 6 feet thick.