The Response of Cemented Mill Tailings Backfill to Shockwave Loading
Jeff Johnson, Paul Pierce,
Abstract: A series of static and dynamic tests were conducted at NIOSH’s Spokane Research Laboratory to determine the effectiveness of using cemented mill tailings as backfill for underhand stopes in mines prone to rockbursts. This paper documents the findings of this study and the testing apparatus used to conduct dynamic tests. Underhand mining with cemented mill tailings for backfill has proven to be an effective alternative for mining in rockburst prone mines. Moreover, the ability of the cemented sandfill to absorb the energy from the rockburst shock-wave without failing has been proven at the mines in the Coeur d’Alene Mining District many times in the last twenty years. To better understand the response of cemented backfill to shock loading, a series of dynamic tests were performed on samples of cemented mill tailings backfill from an underground mine in North Idaho. Cylindrically-shaped cemented backfill samples were placed in a split Hopkinson pressure bar testing machine and a moderate shockwave was applied to each sample. The tests showed that the cemented sandfill absorbed up to 98.5% of the input shockwave energy.
