MINE SAFETY HEARINGS BEFORE A SUBCOMMITTEE OF THE COMMITTEE ON LABOR AND PUBLIC WELFARE EIGHTY-FIRST CONGRESS FIRST SESSION ON S. 1031 A BILL AMENDING PUBLIC LAW 49, SEVENTY-SEVENTH 92320 MAY 18, 19, 24, 25, 26, 27, AND 31, 1949 Printed for the use of the Committee on Labor and Public Welfare UNITED STATES WASHINGTON: 1949 |