Numerical investigation on the caving mechanism with different standard deviations of top coal block size in LTCC

• DOI: 10.1016/j.ijmst.2020.06.001
• Publication Date: 2020-06-10T02:00:19Z
• Authors: Jiachen Wang; Weijie Wei; Jinwang Zhang; Brijes Mishra; Ang Li
• Keywords: Surface-area-to-volume ratio; Aspect ratio (aeronautics)

The size distribution of the broken top coal blocks is an important factor, affecting recovery ratio and efficiency drawing in longwall caving (LTCC) mining panel. standard deviation block (δt) one main parameters to reflect coal. To find effect δt on mechanism, this study simulates experiments with 9 different by using discrete element software PFC. divided into two stages: uniform stage (UDS) whose less than 0.1 (Schemes 1–5), nonuniform (NDS) more 6–9). This research mainly investigates variation ratio, body shape, boundary coal, contact force between particles stages, respectively. results showed that increasing δt, panel increases first then decreases UDS. It largest Scheme 3, which volume at side starting end. However, quickly NDS, it 9, where finishing end are relatively higher. In UDS, major basically medium, while varies from medium small, large, a distinct difference shape body. When cross-section width initial each height small. Conversely, when has larger opening range, rotating angle lower small normal stage, conducive development reduces residual maximum particle velocity movement both larger. lays foundation for prediction suggests manageable ratio.