This report is the third of a series on the environmental effects of strip mining of coal in Cane Branch basin, McCreary County, Ky. The series of reports, which is being published by the U.S. Geological Survey as Professional Paper 427, is the product of a cooperative study by several Federal and State agencies. The physical environment of the study areas and the history of mining in the basin are described in the first report, Professional Paper 427-A (Musser, 1963). Results obtained during the study period 1955-59 and definitions of terms are given in the second report, Professional Paper 427-B (Collier and others, 1964). The present report describes the results of the investigation since 1955, with emphasis on the period 1959-66.