Regulation of Surface Mining: Hearings Before the Subcommittee on the Environment and Subcommittee on Mines and Mining of the Committee on Interior and Insular Affairs, House of Representatives, Ninety-third Congress, First Session, on H.R. 3 and Related Bills, Relating to the Regulation of Surface Mining, Hearings Held April 9, 10, 16, and 17, 1973, and May 14 and 15, 1973