| Abstract |
This report documents the process of literature review, site selection, instrument installation, data acquisition, and preliminary data reduction performed to evaluate the influence of rock mass discontinuities on coal mine subsidence. A system of surface, subsurface, and mine level instrumentation was installed at the Armco No. 7 Mine in Montcoal, WV, where the overburden ranged from 630 to 1,040 ft thick. Survey monuments, borehole pressure cells, full profile borehole inclinometer-extensometers, mine level extensometers, stressmeters, and tape extensometer convergence stations were installed to monitor displacements and stress changes. Final design of the instrumentation system was based on (1) review of available information, (2) field mapping and analysis of areal photography, (3) drilling, and (4) borehole geophysics. The report contains the complete graphed data of stress and displacements accompanying the longwall mining of a 4,800-ft-long by 480-ft-wide coal panel. |
