HEALTH AND SAFETY IN THE COAL MINES HEARING BEFORE THE SUBCOMMITTEE ON LABOR OF THE COMMITTEE ON LABOR AND PUBLIC WELFARE NINETY-FIRST CONGRESS SECOND SESSION ON HEALTH AND SAFETY IN THE COAL MINES CENTERVILLE, PA. WASHINGTON, D.C. AUGUST 6, 7 AND 14, 1970 CHARLESTON, W. VA. AUGUST 17, 1970 Printed for the use of the Committee on Labor and Public Welfare 47-135 O U.S GOVERNMENT PRINTING OFFICE WASHINGTON: 1971 |