Simulation of Regional Collapses in Bord & Pillar Workings
Three dimensional modelling of a documented subsidence event in the Witbank coalfield, aimed at reserves in the seam above old workings that current pillar strength formulae sterilise.
Finite element simulation reproduced the rapid collapse of bord and pillar workings in the 2 Seam at a Witbank colliery, showing that progressive pillar deterioration triggers snap through of a strong sandstone plate in the overburden. Too little was known about the chosen collapse to back out a real pillar safety factor, so the calibration goal was not met.
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