Rock Mechanics Study on the Recovery of Residual Pillars in Pinglidian Gold Mine, China

The Pinglidian gold mine locates at the Laizhou city, Shandong province, China. Up to 2013, the orebodies had been mined out, however, there is leaving mined voids of about 120,000 m 2 and also leaving a large number of ore pillars. The residual pillars have to be recovered. In order to safely recover those residual pillars in the mine, some rock mechanics study work, including the detection of roof loosening layer depth of mined voids, the 3-d numerical modeling and the field monitoring of the stresses changing of pillars adjacent to recovering operation, has been done, and for recovery operation of backfill method with hydraulic prop supporting, the required mechanical properties of cemented tailings fill materials have been tested. Finally, a trial recovering stope has been successfully and safely mined.