Examination of the Support Potential of Cemented Fills for Rock Burst Control.
Whyatt JK; Williams TJ; Board MP
Innovations in Mng Backfill Tech Proc 4th Int Symp Min W/backfill Balkema PP 209-215 :209-215
Recent interest in switching from the traditional overhand cut-and- fill mining method to the underhand longwall cut-and-fill method as a step towards controlling the rock burst problem in the Coeur d'Alene Mining District has focused attention on underhand backfilling practices. The underhand method requires the backfill to function as a stable roof during mining and makes filling a cut tight to the sandfill back difficult. The gap increases the stope closure required to load the fill significantly and thus increases the effective span between mining face and backfill abutment. The influence of changes in backfill density and placement gap on the rock burst hazard were examined with an energy release rate (err) analysis. South African studies suggest that err is related to rock bursts triggered by pillar and abutment crushing, but not by discontinuity stick-slip. Both triggering mechanisms play an important role in the rock burst problems in the Coeur d'Alene District. The analysis was based on the assumption of an elastic rock mass, which was checked by an elastoplastic parametric study. The err analysis showed that changing from present practice to one in which backfill is omitted altogether increases err by 42 pct, while "ideal" backfill reduces err an additional 28 pct. The most promising avenue for further reduction in err is elimination of the gap, which accounts for half of the err difference between present practice and the ideal case. The ideal backfill case also requires placing backfill at maximum density. While improvements in backfill density have bee
Innovations in Mng. Backfill Tech. (Proc. 4th Int. Symp. Min. W/backfill), Balkema, PP. 209-215