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The conditions for rockbursts occurrence are traditionally identified as: high stress, high extraction ratio, strong brittle rocks, folding, faulting and unfavourable excavation geometry. Some rockbursts cannot be explained by any one or a combination of these factors. Salamon (1983) stated that a disconcerting feature of rockbursts is that they defy conventional explanation. Based on detailed review of case histories, this paper identifies oblique loading of orebodies by the major far field principal stress as a cause of rockbursts. Orebodies subjected to this loading condition are termed orebodies in shear. Orebodies in shear are subjected to compressive and shear loads. This paper shows it is risky to generalise that tabular orebodies have their axis perpendicular to the major far field principal stress. This study identifies characteristics of orebodies in shear and the consequences of not taking this loading mechanism into account in the planning, design and mining of such orebodies.

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This paper reports on an ongoing analysis of support performance at Vale's Creighton Mine covering the period from January 2000 to September 2011. A database was constructed of 133 rockbursts and the associated damage to support systems at 191 locations. The main source of information has been obtained through the seismic systems and on-site assessments. This work validates the information collected on site in order to quantify the performance of different support systems in a seismically active mine. 2 Data collection For the purpose of this investigation, it was decided to focus on data from one mine site. Creighton Mine of Vale was selected due to its long history of mining, seismicity and rockburst, the quality of its seismic data, and the considerably large range of event magnitudes recorded. The mine has always had a dedicated ground control team. A variety of rock support systems have been tested at Creighton during the past, making this mine site even more interesting for passive monitoring of support performance. This section provides the necessary background on the local geology at Creighton, mining methods and ground support practices. Sources of information available on-site and data collected are further reviewed. https://papers.acg.uwa.edu.au/p/1201_02_morissette/ Validating a support performance database based on passive monitoring data P. Morissette et al.