Authors: Collins, DS; Toya, Y; Pinnock, I; Shumila, V; Hosseini, Z


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Collins, DS, Toya, Y, Pinnock, I, Shumila, V & Hosseini, Z 2014, '3D velocity model with complex geology and voids for microseismic location and mechanism', in M Hudyma & Y Potvin (eds), Deep Mining 2014: Proceedings of the Seventh International Conference on Deep and High Stress Mining, Australian Centre for Geomechanics, Perth, pp. 681-688,

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A microseismic monitoring system provides a vital window into a rock mass to see where stress induced fracturing is occurring in relation to mining operations. A main factor for the accuracy of the microseismic locations is the velocity model assumed for the rock mass. The majority of mines that use microseismic systems use a single velocity model for location purposes which assumes the same elastic modulus properties throughout the volume. This study shows examples of event locations that were calculated using a velocity model that accounts for multiple complex shaped geological units each with their own properties. The method allows multiple voids to be added that could be air filled, brine filled, or cement paste back filled, thus mimicking mining and geotechnical operations such as stope mining, cave mining, solution mining, or underground cavern storage. Going beyond the dots, microseismic systems provide an important way to understand the failure mechanics of the rock fracturing. With good data quality, each located event can be solved for the source mechanism (moment tensor) and interpreted in terms of whether the event is dominantly tensile opening, closing, or shear slip. The orientation of each event failed zone can be quantified providing useful information about the discrete fracture network (DFN). This paper provides examples of source mechanism solutions using a full 3D velocity model. It is shown that the ray path of each sensor does affect the source mechanism solution when comparing a single velocity model solution and a 3D velocity model solution. Microseismic systems offer important daily information for mine operation, safety and planning. Improvements to the accuracy of seismic results by using enhanced processing methods and regular calibration, allow a mine to more confidently integrate seismic results with numerical models and make decisions. This is especially important as mines move to different excavation methods such as block caving and extend to greater depths and stresses.

Alexander, J, Trifu, CI 2005, ‘Monitoring mine seismicity in Canada’, in Y Potvin and M Hudyma (eds), Proceedings of the Sixth International Symposium on Rockburst and Seismicity in Mines: RaSiM6, Australian Centre for Geomechanics, Perth, pp. 353-358.
Baig, A, Urbancic, T & Wuesterfeld, A 2012, ‘Variability of hydraulic fractures in shale or tight gas reservoirs’, in RF Broadhead (ed.). Proceedings of the Tenth Middle East Geosciences Conference, American Association of Petroleum Geologists, Tulsa, Article #90141.
Collins, DS, Pettitt, WS & Young, RP 2002, ‘High resolution mechanics of a microearthquake sequence’, Pure Applied Geophysics, vol. 159, pp. 197-219.
Collins, DS, Pinnock, I, Toya, Y, Shumila, V & Trifu, CI 2014, ‘Seismic event location and source mechanism accounting for complex block geology and voids’, in P Smeallie & J Roberts (eds), Proceedings of the 48th ARMA US Rock Mechanics/Geomechanics Symposium, American Rock Mechanics Association, Alexandria, paper 14-7530.
Collins, DS, Pinnock, I, Shumila, V, Trifu, CI, Kamp, C, Davies, A & Chan, A 2013, ‘Optimizing microseismic source event location by applying a variable velocity model to a complex geological and mining setting at the New Gold New Afton Block Cave’, in FP Hassani (ed.), Proceedings of the 23rd World Mining Congress on Advances in Mining Engineering, Canadian Institute of Mining, Metallurgy and Petroleum, Westmount, PDF paper 674.
Gephart, JW & Forsyth, DW 1984, ‘An improved method for determining the regional stress tensor using earthquake focal mechanism data: application to the San Fernando earthquake sequence’, Journal of Geophysical Research, vol. 89, pp. 9305-9320.
Trifu, CI & Shumila, V 2002, ‘The use of uniaxial recordings in moment tensor inversions for induced seismic sources’, Tectonophysics, vol. 356, pp. 171-180.
Trifu, CI & Shumila, V 2011, ‘The analysis of stress tensor determined from seismic moment tensor solutions at Goldex Mine Quebec’, in P Smeallie & J Roberts (eds), Proceedings of the 45th ARMA US Rock Mechanics Symposium, American Rock Mechanics Association, Alexandria, paper 11-584.
Trifu, CI & Shumila, V 2010, ‘Geometrical and inhomogeneous raypath effects on the characterization of open pit seismicity’, in P Smeallie & J Roberts (eds), Proceedings of the 44th ARMA US Rock Mechanics Symposium, American Rock Mechanics Association, Alexandria, paper 10-406.
Trifu, CI, Shumila, V & Burgio, N 2007, ‘Characterization of the caving front at Ridgeway Mine, New South Wales, based on geomechanical data and detailed microseismic analysis’, in Y Potvin, J Hadjigeorgiou & TR Stacey (eds), in Challenges in Deep and High Stress Mining, Australian Centre for Geomechanics, Perth, pp. 445-453.
Wu, X, Liu, C, Hosseini, Z & Trifu, CI 2012, ‘Applications of microseismic monitoring in Chinas underground coal mines’, in TM Barczak (ed.), Proceedings of the 31st International Conference on Ground Control in Mining, pp. 130-137, Published by International Conference on Ground Control in Mining, West Virginia.

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