The importance of barrier pillars in controlling load transfer and seismicity in U.S. burst-prone mines

Maleki H.; Jaramillo B. · Rock Mechanics for Natural Resources and Infrastructure Development- Proceedings of the 14th International Congress on Rock Mechanics and Rock Engineering, ISRM 2019 (2020)

Resumen

Using four decades of geotechnical monitoring and stress analyses in three US burst-prone operations, the importance of barrier pillars in controlling caving, stress transfer and seismicity is demonstrated. Efforts to eliminate barrier pillars fail in the first case study while a marginally sized barrier contributes to a 4.2 seismic event in the second case study mine under deep cover (760-m). On the contrary, the effectiveness of a 150-m wide barrier pillar is shown in the third case mining under stiff lithologic conditions of Utah; the study confirms a remarkable reduction in the number of events per kilometer (a factor of 4 to 8) in comparison to the initial mining district using side-by-side longwall extraction. The importance of gate and barrier pillar designs for stress and seismicity control is demonstrated using geotechnical data and stress monitoring from three case studies.