Case studies are presented from Glencores’ Fraser Copper, Fraser Morgan and Nickel Rim South Mines showing how microseismic monitoring data can be used as an aid to rock mechanics decision making and design verification. At Nickel Rim South and Fraser Morgan, examples of how recorded development blasts can be used to quickly evaluate source location accuracy and infer the state of rockmass conditions are given. Examples are given as to how network sensitivity can enhance the understanding of the rockmass response to mining are also presented and a case is made for 3D velocity models and recognizing the impact of waveform attenuation from raypath effects, and yielded rockmass conditions. At Fraser Copper, a case history shows how seismic information was useful for evaluating the performance of a successful longhole destress blast that was performed when face-bursting was encountered during a planned underhand extraction of a highly stressed remnant.
Glencore’s Sudbury Integrated Nickel Operations includes three underground operations, the Nickel Rim South Mine, Fraser Copper Mine, and Fraser Morgan Mine, all located near Sudbury, Ontario, Canada (Figure 1).
Fraser Morgan is a nickel deposit accessed via the Fraser Copper Mine infrastructure. Close to 2 million tonnes per year of ore are mined underground from all operations, with Nickel Rim South providing the majority of the material at 1.3 Mt/year.
All three operations are hard rock mines, with excellent rockmass quality. The depth of mining is sufficient to develop pervasive stress fracturing around most openings (Figure 2).