01228nam 2200361Ka 450 991069683170332120080728111159.0(CKB)5470000002382567(OCoLC)236167347(EXLCZ)99547000000238256720080728d1974 ua 0engtxtrdacontentcrdamediacrrdacarrierTracer gas as an aid in mine ventilation analysis[electronic resource] /E.D. Thimons and F.N. Kissell[Pittsburgh, Pa.?] :U.S. Dept. of the Interior, Bureau of Mines,[1974]17 pages digital, PDF fileReport of investigations ;7917Title from title screen (viewed on July 28, 2008).Mine ventilationSulfur hexafluoride as a test gasMine ventilation.Sulfur hexafluoride as a test gas.Thimons Edward D1391026Kissell Fred N1351621United States.Bureau of Mines.GPOGPOBOOK9910696831703321Tracer gas as an aid in mine ventilation analysis3522649UNINA