Study of stress conditions at Williams Mine using underground observations and microseismic monitoring data

Authors: Earl, PJ; Malovichko, D; Rebuli, D Download Paper

DOI https://doi.org/10.36487/ACG_rep/1511_06_Earl

Cite As:
Earl, PJ, Malovichko, D & Rebuli, D 2015, 'Study of stress conditions at Williams Mine using underground observations and microseismic monitoring data', in Y Potvin (ed.), Design Methods 2015: Proceedings of the International Seminar on Design Methods in Underground Mining, Australian Centre for Geomechanics, Perth, pp. 149-163, https://doi.org/10.36487/ACG_rep/1511_06_Earl



Abstract:
The C Zone/Interlake orebody at Williams Mine, Ontario, Canada, is one of the Hemlo ore-bearing lodes. It is adjacent to the B Zone orebody, for which the stress state has been well studied, with evidence supported by underground observations. The extrapolation of stress conditions from B Zone to C Zone/Interlake seemed logical, thus common characteristics of in situ stress were previously used for design and planning purposes. Over time, a number of discrepancies were found between the assumed stress state and underground observations (damage of boreholes and orepasses) around the C Zone/Interlake orebody. An alternative model of in situ stress was considered for the C Zone/Interlake region. The induced stresses were evaluated for a mining sequence for both old and new models. The recorded seismic response to the modelled sequence was compared with the expected response in terms of location and source mechanisms of seismic events. The new model shows better agreement, increasing confidence in numerical stress models used for C Zone/Interlake mine planning.

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