Show I Keeping e Up 11 nf clen e I erv ce p 0 WI I e. e 1 Mine Roof Ins Cave May Ia Be Predicted I 1 by New Instrument May Mean Prevention Pre of Future Catastrophes STATE COLLEGE A new d device to detect mine roof cave ins and the type of disaster disaster dius ter which occurred recently at Moose River N. N S. S has been developed at the Pennsylvania State Sute college here The frantic and ape spectacular rescue res f cue cne which saved sated the Tires lives of ot two men at Moose River e em m m- m aD anew eW the hazard which bleb ro root f collapse brings to mining operations opera doni and recalls the fact that K ii per cent of all deaths In Ie well kept t commercial coal mJ mines occur f from tom this water source Dr H. H Landsberg o of the S School hool of ot Mineral Industries has hu found thaila that thai t la In In aU roof lot las so 10 far studied d a t definite break occurs CUrs in the overhead over head bead rock strata several tenth eera hours bona before be be- fore tore the flail final In cave takes place plat e. e Tb The shale and IDd dirt he be found fond support support sup sup- P port the roof for tor some IOme time after r the supporting rock has hu gone gODe beyond beyond be yond lond It Its I breaking point Detects Initial Break The secret of ot success of ot Doctor Docto r re Landberg device Is 11 to detect th the e Initial break In la time to warn th the e wor working miners Ills Ilis Instrument Is tit called a convergence recorder From m Its use can be made predictions ns much mw like Ilke those a weather man ma mamake may T make after reading the barometer The apparatus consists of ot t o osteel steel tubes which slide Inside one on e another like the tubes on a tro m bone The sliding tubes are kept kepi apart by hI a spring and aDd are pia placed I la In the mine so 10 that one tube touches touch ea the roof root and aDd the other the floor othe o of f the shaft haft A movement as small as IJ 1 10 of ot an Inch between roof root an and il toiling ceiling can be detected Predicts Time Tim of Crash Following the Initial break Doctor Doc lAx e etor tor Landsberg points out the rates rate 3 of convergence of the roof an and floor r Increase rapidly until the end entire re mine roof root collapses By fly studying Lb the e rates of ot convergence the exact exec t time at which the internal roc rock k structure was broken can be detected detect detected ed and aDd the final OMI In cave predicted Further work la Is being done alon along this line by both Doctor Landsberg rg and the United States bureau a amines of t mines In la an effort to establish amore a amore amore more definite relationship between tween the rates rate of ot convergence of the root roof and floor of ot a mine and the collapse col col- collapse lapse of the roof structure |