Examination of fault-slip induced rockbursting at the Strathcona Mine

The Strathcona Mine of Falconbridge Ltd., in the Sudbury, Ontario basin, is currently extracting the main mine sill using long- hole uppers and a transverse blasthole stoping method. During mining of the 200 panel (2250–2500 levels), several 2–3 M n rockbursts were experienced, with damage centered in hangingwall drifts. Examination of microseismic data and a reconnaissance of the stope and adjacent drifts indicated that the activity was related to a slickensided dyke and fault structure which intersect in the panel hangingwall. The three-dimensional distinct element code 3DEC was considered the most appropriate computational tool to investigate the problem of fault and dyke slip associated with the rockbursting. This modeling approach identifies the distinct three-dimensional pattern of the intersecting dyke, fault and mine sill as an important contributing factor to the resulting fault-slip motion. The identification of mining conditions affecting fault-slip was performed by comparing induced slip along the fault and dyke structures as calculated by the model to microseismic data gathered before and after the rockbursting. The comparative analyses provide a basis for identifying key factors affecting the fault-slip problem. Confirmation of the model results also provide justification for further simulations to predict the consequences of continued extraction of the main mine sill.