Continuous Recorder to Monitor Mine Roof Displacement.
NTIS: PB 277 265 :12 pages
This report describes an instrument system developed by the Bureau of Mines to continuously monitor and record changes in roof displacement during underground mining activity. The instrument consists of a single-wire extensometer coupled to a mechanical-drive chart recorder mounted in an aluminum frame installed in the roof. The unit is small and simple to install and meets safety requirements for use in underground coal mines.
NTIS Accession No.
NTIS: PB 277 265