Abstract:

Westwood Mine had few episodes of increased seismic activities. Seismic activities at the mine might be related to the nature of the mine orebody and its geology structures. The current geotechnical characterizations such as the RMR, GSI and Q' index can define the general rock quality as well as the zones at risk of convergence (squeezing ) but do not make it possible to properly target the zones at seismic risk.

The experience at Westwood mine has demonstrated a correlation between seismicity and areas with strong rheology contrasts (e.g. alternating hard rock and soft rock). The contrast between two units is characterized by the difference in the uniaxial compressive strength of these two units. UCS laboratory testing of different mixtures of geological and alteration units can be expensive with laboratory methods.

For this characterization we made 300 UCS test and geochemical data was associated with these samples. Then, some statistical manipulation was done with IOGAS software and finally transferred to Leapfrog geo to make a block model of resistance.

Back-analysis of certain seismic sectors of the Westwood mine validated this contrast model. With this research project, it was therefore possible to establish a geomechanical tool to identify areas with high seismic risk. Once these areas have been identified, it is possible to put in place mitigation measures to minimize the operational impact of this seismicity.

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Mr. Maxim Martel