Subsurface exploration for stripping coal on Lower Deep Creek, Homer district, Kenai coal field, Alaska

Abstract

The area described in this report is on the west side of the Kenai Peninsula in south-central Alaska, near the mouth of Deep Creek, a stream of moderate size that enters Cook Inlet about 2 miles south of the village of Ninilchik (pl. 1). It is 37 miles by highway north of Homer and 51 miles south of Kenai, the two principal towns of the region (fig. 1). The localities studied are in sections 2, 3, 10, and 11, T. 2 S., R. 14 W. (Seward meridian), south and west of Deep Creek within 2 miles of its mouth, and were easily reached by cutting about a mile of tractor trail from a dirt road connecting with the Sterling Highway (pl. 1). This area was chosen for detailed study because geologic mapping had indicated the presence of at least one coal bed of minable thickness and quality that appeared to be favorably situated for strip mining and was reasonably accessible to the highway. This report presents the results of drilling and trenching with a bulldozer and power-auger unit in areas along Deep Creek that had been mapped by Cobb (1952) and briefly examined by Barnes in 1953. The reader is referred to Cobb's report for a general description of the geology and coal resources of the Homer district, of which this area is a part. These earlier investigations showed that the coal-bearing Kenai formation, of Tertiary age, is generally covered by Quaternary glacial and stream deposits, except in steep bluffs and parts of the creek bed, so that subsurface data were needed to supplement the surface data in evaluating the coal reserves. The field work for this report was done in the period August 130, 1954, by the writers, assisted by A. E. Burford and W. S. Hopkins, geologists, and J. W. Dawson, operator-mechanic. It involved the use of a small crawler tractor, equipped with a 4-1/2 inch power auger for boring through the overburden to test concealed coal beds, and with a bulldozer for building access roads and opening cuts and trenches to permit direct observation and measurement of the coal at favorable localities. A more detailed description of the equipment and its use is given elsewhere (Barnes and Sokol, 1955). Work was done at two localities on Deep Creek, about 1 mile and 1-1/2 miles, respectively, above the highway bridge. These areas were mapped topographically and tied in with the land net by plane-table surveys.