Abstract:
This study explores the use of backfill in hard rock bord-and-pillar mines to increase the pillar
strength and extraction ratio at depth. The use of backfill will also minimize the requirement for
tailings storage on surface and the risk of environmental damage. A literature survey indicated
that backfill is extensively used in coal mines, but rarely in hard rock bord-and-pillar mines. To
simulate the effect of backfill confinement on pillar strength, an extension of the limit equilibrium
model is proposed. Numerical modelling of an actual platinum mine layout is used to illustrate
the beneficial effect of backfill on pillar stability at greater depths. The magnitude of confinement
exerted by the backfill on the pillar sidewalls is unknown, however, and this needs to be quantified
using experimental backfill mining sections equipped with suitable instrumentation.
