In-Situ Measurements of Cemented Paste Backfill in Long-hole Stopes
Rock Engineering 2009 - Rock Engineering in Difficult Conditions
Ben D Thompson, David B Counter, Murray Grabinsky, William F Bawden,
Cemented Paste Backfill has proven of critical importance to the operation of a number of Canadian mines, primarily due to the rapid backfilling rate this method permits. In order to improve the efficiency of this backfill system (i.e. optimizing binder contents, fill fence design, and the employment of two stage filling strategies) there is a requirement to better understand its geomechanical behaviour. In response, in-situ experiments have been conducted in long-hole stopes to quantify the evolution of total earth pressures and pore pressures at a series of points both within the backfill and close to fill fence locations. The deflection of fill fences as a result of paste loading has also been measured and additional instrumentation employed to measure cement hydration, negative pore pressures, and blasting induced vibrations within the paste backfill. Installing geotechnical instrumentation within an open long-hole stope can be an extremely complex procedure and this paper details the methods that have been successfully employed. Preliminary results are presented, and the pressures induced for backfill with differing binder contents, at a number of different in-stope locations are considered.