Resistivity Roof Fall Warning System in the White Pine Mine.
Gibbons-M; Farstad-AJ; Kehrman-RF
NTIS: PB/80-186547 :75 pages
A method of monitoring roof stability in underground mines by detecting the changes in resistivity of roof material was tested. The device was tested over a 16-month period at the White Pine Copper Mine in Michigan. Three falls of ground were monitored by as many as 11 sensors. Data indicate a correlation between changes in resistivity and impending structural failure. Problems were encountered with the high roof electrode impedance in the winter and spring due to the drying out of the roof material. Difficulties also developed in obtaining a permanent bond between the roof rock, the conductive epoxy, and the electrode plate. Some data were lost due to timer and fuse problems within the unit, but these were eventually rectified.
CP; Final Contract Report;
NTIS Accession No.
Westinghouse Electric Corp.