ABSTRACT
Mines use gravity flow to transport ore and waste rock to lower mine levels. Hang-ups occur where rock becomes stuck along the vertical route and are sometimes dangerous to release. Ore is made up of both coarse and fine rock material. Laboratory tests were performed on ore fines from one mine to determine unconfined compressive strength. Strength was verified using PFC2D computer code and to determine PFC2D properties for input into an ore pass model. Ore pass simulations were carried out in PFC2D using distinct elements for the fine particles, clumped elements for coarse particles, and the “Wall” command to simulate the extents of the ore pass. The modeled fine ore tended to flow intermittently and showed funnel flow characteristics. It also contributed to hang-ups with the large particles. The laboratory tests and models provide a method to characterize the hang-up potential of ore and if used in designing ore passes, could possibly decrease the risk of injury to miners.
