Abstract

Seismicity in the mining environment is controlled by factors including stope and development blasting, the presence of geological features, and stress conditions. The Goldcorp Eleonore mine is located in the James Bay region, Quebec, Canada. It's 800-metre depth makes Eleonore a relatively shallow mine when compared to other seismically active Canadian mines. Despite the mine's depth, seismicity is a geotechnical hazard that may be arguably attributed to a particular stress regime and complex geology. An improved understanding of the seismic responses following blasting can decrease seismic risk and is beneficial to mine planning and productivity. Seismic responses to blasting were spatially delineated using a density-based clustering approach. The spatial characteristics of clusters were assessed using Principal Component Analysis (PCA). The best-fit planar representation of seismic event clusters was identified. The orientation of the best-fit planar representations was then compared to the mine's local jointing to investigate the causative seismic source mechanism for these events. The results of this study show that seismicity is linked to local jointing, and in particular to the different structural domains.

1.
Introduction

Blasting is a significant factor in triggering seismic events at mine sites (Vallejos and McKinnon, 2008). Seismicity is defined as a stress wave resulting from inelastic deformation or failure in the rock mass (Hudyma and Mikula, 2002). Seismicity in the mining environment is controlled by factors including stress, geological structures or rock mass weakness, and mining activities. This induced seismicity—directly connected to mining operations—is associated with formations of fractures at stope faces and with movement on major discontinuities (Gibowiicz and Kijko, 1994). Fig. 1 illustrates the different source mechanisms of induced seismicity in an underground mine environment (Hudyma et al., 2003). Many authors have observed that well-located seismic events exhibit strong spatial clustering (Leslie and Vezina, 2001; Dogde and Sprenke, 1992; Kijko et al., 1993). Hudyma and Mikula (2002) hypothesized that clusters of seismic events represent a separate seismic source mechanism. Limited quantitative means of assessing a seismic source mechanism have been presented in the scientific literature especially in the case of clusters of seismic events. A better understanding of induced seismicity source mechanisms in underground mining can help to optimize mining operations, reduce delays and production losses. Understanding the main source mechanism in mines is essential to a better prediction of the rock mass response to mining.

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