Effect of microwave heating on thermo-mechanical behavior of cemented tailings backfill

Abstract

Cemented tailings backfill (CTB), which is a mixture of tailings, binder and water, is used to fill underground mined-out areas. Once placed, the CTB is required to provide enough ground support as soon as possible, in order to improve the mining efficiency. A relatively high temperature can accelerate the consolidation of CTB, and microwave radiation can afford a quick temperature rise. Therefore, this study proposed an experimental program incorporating the microwave heating into the conventional curing of the CTB samples. The thermal behavior and strength development of the CTB was investigated, and the CTB deformation under gravity and compression was also evaluated. The obtained results showed that the microwave radiation could significantly increase the CTB temperature. Besides, the microwave heating could either enhance or reduce the mechanical performance of the CTB samples with different curing ages, depending on when the microwave radiation was applied (delay time) and how long it lasted (heating time). This study demonstrates that the microwave technique can definitely be used in mine backfill, for improving the thermo-mechanical performance of the backfill.