01404nam 2200373I 450 991070709700332120180627140535.0(CKB)5470000002460513(OCoLC)1034692875(EXLCZ)99547000000246051320180507d1950 ua 0engur|||||||||||txtrdacontentcrdamediacrrdacarrierSome innovations in equipment for scaling high roofs and mine walls /Brinton C. Brown, Fred D. Wright, and Homer J. Ballinger[Washington, D.C.] :United States Department of the Interior, Bureau of Mines,1950.1 online resource (11 pages) illustrationsReport of investigations / United States Department of the Interior, Bureau of Mines ;4739"October 1950."Includes bibliographical references (pages 9-11).Coal mines and miningEquipment and suppliesCoal mines and miningEquipment and supplies.Brown Brinton C.1414880Wright Fred D.Ballinger Homer J.United States.Bureau of Mines,GPOGPOBOOK9910707097003321Some innovations in equipment for scaling high roofs and mine walls3515345UNINA