Sublevel Shrinkage (SLSh) Mining—A State-of-the-art Review

Abstract

Sublevel shrinkage (SLSh) is an underground mining method similar to sublevel caving (SLC) but with continuous backfilling from the top. It features a top-down mining sequence with production drifts orientated in a longitudinal or transverse way in the orebody. Fan drilling and blasting is done from the production drifts, from where the ore is then drawn. While drawing, backfill is introduced at the top and flows down by gravity, which supports the walls and prevents caving. In this contribution, a state-of-the-art literature review is performed using various sources. Four case studies show that SLSh could be a viable alternative for stoping (e.g. sublevel open stoping “SLOS” or longhole open stoping “LHOS”) and SLC in steeply dipping, moderately thick, tabular deposits. SLSh can be applied where caving must be prevented or caveability of the hangingwall rock mass is not provided due to rock mass properties or the geometry of the deposit. SLSh also proved to be an alternative to SLOS or LHOS when only small stope sizes would be possible due to geotechnical constraints. Critical points are dilution with backfill and the backfill handling infrastructure that must have a high capacity. Stability of this infrastructure is very important and must be monitored closely. Open points are the application in massive deposits and backfill supply and handling for mines with very high production.