Strategies for mining in highly burst-prone ground conditions at Vale Garson Mine

摘要

While mining at depth in #1 Shear East orebodyfrom 4700 Level to 5100 Level at Vale's Garson Mine in the Sudbury Basin, several major seismic events have occurred. The largest of these events recorded a magnitude of 3.1 Mn (Nuttli), resulting in substantial damage to underground openings on multiple levels. Described within this paper are the findings from an extensive review of those major seismic events focusing on the determination of source mechanisms. Both strategic and tactical mitigation measures to withstand future seismic impact are presented in the paper. Strategic measures include: developing an engineering geology model to identify all future high risk zones; undertaking numerical modelling to re-examine mining sequence; and investigating a mining layout change from transverse to longitudinal mining to gain a favourable stress environment. Tactical measures include: developing a methodology to determine the types of enhanced support required for high risk zones and standardising ground support practices when mining through various active dykes.