Ohio Department of Natural Resources, and Marietta Coal Co., No description specified. 1-2 (2 Records) Documents Phase I / II Archaeological Investigation, Porterfield Coal Mine, Richland Township, Belmont County, Ohio, Permit Application No. 1070 (1989) Phase I and Phase II Archaeological Survey of the Protiva Mining Area, Richland and Smith Townships, Belmont County, Ohio (1990)