| Show Keeping Up cien I e 0 Sc n erv e O C nw s servIce Mine l Roof Ins Cave May fay Be Predicted by hy New Instrument May Mean Prevention of Future Catastrophes STATE COLLEGE PA A A A Anew Anew new device to detect mine roof ins cave-ins and the type of disaster disaster disaster ter which occurred recently at Moose River N. N S. S has been developed at the Pennsylvania State college here The frantic and spectacular rescue rescue rescue res res- cue efforts which saved sAYed the lives of two men at Moose River emphasize emphasize em em- anew the hazard bazard which roof collapse brings to mining operations operations opera opera- and recalls the fact tact that CO ro COper roper per cent of all deaths In la well kept commercial coal mines occur from this source Dr U. U Landsberg of the School of Mineral Industries has baR found that In all roof root cave las so far studied a definite break occurs occur In la the overhead overhead overhead over over- head rock strata several hours before before be be- fore tore the final In cave-In takes place The shale and dirt he be found support support support sup sup- port the roof for some time after atter the supporting rock has bas gone beyond beyond be be- yond rond Its Ita breaking point Detects Detect Initial Break The secret of ot success ot of Doctor Landberg's device Is to detect the I Initial break In time to warn the working miners Ills JUs Instrument Is called a convergence recorder From rom It Its use can be made predictions much like those a weather man nan may make after reading the barometer The apparatus consists of t o steel tubes which slide Inside one another like the tubes on a bone The sliding tubes are kept apart by a spring and are placed In the mine so that one tube touches the roof root and the other the floor of ot the shaft A A. movement as small as 1 of an Inch between roof and ceiling can be detected Predicts Time of Crash Following the Initial break Doctor Doctor Doc Doc- tor tot Landsberg points out the rates of convergence of ot the roof and floor noor Increase rapidly until the entire mine roof rouf collapses By Dy studying the rates of ot convergence the exact time at which the Internal rock structure was broken can be d detected detect detect- ed and the final cave In predicted Further work Is being done along this line by both Doctor Landsberg and the United States bureau of ot mines In an effort to establish a amore amore amore more definite relationship between the rated of ot convergence of the roof and floor of a mine and and the colI collapse collapse col col- I lapse of the roof root structure |
