ABSTRACT
Research has been conducted to provide a scientific basis for the use of granular halite backfill in underground potash mines in Canada. An extensive testing program was undertaken to identify compaction creep behaviour of halite backfill, and define its strength and stiffness as a function of fractional density. A brief summary of laboratory methods and accompanying results are outlined within the paper.
Examination of laboratory results highlighted three mechanisms that govern consolidation of halite backfill; pressure solution, particulate sliding, and cataclasis. An empirical constitutive law describing compaction creep behaviour of granular halite backfill was developed by incorporating these mechanisms. Laboratory results, and in situ measurements provided required parameters for calibration of the model.
This constitutive law was implemented into the two dimensional finite difference program FLAC. Several numerical solutions using different initial placement densities were then performed. Results indicate that use of this constitutive law in the numerical program allows prediction of the compaction behaviour of granular halite backfill and the surrounding rock mass.
