Modelling dynamic loading on backfilled stopes in sublevel stoping systems

Sublevel mining methods are very popular in Canadian metal mines, which enable maximum recovery due to pillar-less mining. Ore is recovered by backfilling stopes and mining pillars after curing of backfilled stopes. Backfill material must be engineered to avoid backfill failure leading to dilution of precious ore. Current practice of designing backfill includes only gravity loading (static) on backfill. In reality, backfill is loaded by static and dynamic loads during extraction of adjacent pillars. The static load is due to weight of the backfill and dynamic loading is due to blasting and sudden loss of confinement. It is believed that dynamic loading on backfill must have an influence on backfill stability. This paper presents FLAC3D modelling results of static loading due to gravity and dynamic loading on backfill due to loss of confinement and blasting. The CRF stope is subjected to blast vibrations. The numerical modelling results are compared with the cavity monitoring survey (CMS) profiles of a case study thus validating the modelling technique.