LAUSR

Deep and high-stress mining relies on backfilling the minedout voids to support the surrounding host rock and mitigate rockburst risk. Rational engineering design requires quantifying stress transfer from the host rock to the backfill as mining proceeds. This analysis may be done in either (or both) of the two forms: (i) understanding energy transfer and mining the orebody in a sequence that minimizes energy release rates; (ii) using stress analysis to determine induced backfill stresses and ensure these concentrations will not compromise future attempts to mine beside, under, or through the backfill. In either case, the usual assumptions made regarding backfill constitutive behaviour are relatively trivial (e.g. initially linear elastic behaviour up to a peak strength defined by a Mohr–Coulomb envelope, followed by perfectly plastic response or some assumed degree of strainsoftening). An alternative approach considered here uses one-dimensional consolidation test results to develop a better understanding of a specific backfill’s reaction to closure strains, which could then be incorporated into either energy transfer or conventional stress type analyses. Although the results are specific to the backfill tested, the framework can be generalized and applied to other mining operations with backfill.