For deep mines where a microseismic monitoring programme will be implemented, one of the obstacles during the early stages of mine development is how to obtain adequate three-dimensional microseismic monitoring coverage with minimal access to the rock volume. The ability to utilize existing or planned exploration or geological boreholes for seismic sensor placement is offered as a cost-effective solution to this problem. For existing mines planning to mine new, deeper ore zones, the ability to install seismic sensors in long boreholes is especially important where long ramps are being developed in high-stress/ burst-prone ground where rockbursting could be expected and microseismic monitoring is required as part of a comprehensive ground control safety programme. Lessons learned from the installation and operation of seismic systems at Glencore's Nickel Rim South and Fraser Morgan mines are presented and suggested strategies for establishing new seismic monitoring systems at new mines are discussed. A case study is presented from Glencore's Nickel Rim Deep Project in Sudbury, Ontario, Canada showing how seismic sensors installed in subhorizontal geological ‘scout-holes’ drilled ahead of the ramp development end are being used for monitoring ramp and infrastructure development of a new mining zone in deep high-stress ground.
Establishing microseismic monitoring for mines early in the mine development cycle is important from a worker safety perspective, but early seismic monitoring can also provide valuable information about the nature of the rock mass response to mining when little other rock mass data exists. Seismic information can help identify the seismic nature of different geological units in the rock mass, and may also help determine the location and nature of existing geological discontinuities. The recording of microseismicity early in the mine's life is often the first type of ‘deformation feedback’ from the rock mass available to the ground control engineer, and the seismic information collected in early stages of mine development can enhance the accuracy of numerical models (Beck and Brady, 2001).
