Hayman, LJ 2014, 'Economic and productivity comparison of ground support for rockburst-prone and squeezing ground conditions', in M Hudyma & Y Potvin (eds), Proceedings of the Seventh International Conference on Deep and High Stress Mining
, Australian Centre for Geomechanics, Perth, pp. 329-342.
Rockbursting and squeezing ground conditions in hard rock underground mines worldwide cause mine workers to be exposed to high consequence workplace hazards and have major economic implications. Designing ground support to withstand the anticipated ground conditions is one method of controlling these risks.
A rockburst is defined as damage to an excavation that occurs in a sudden and violent manner and is associated with a mining-induced seismic event, and may cause an unacceptable workplace hazard (Kaiser & Cai 2013). Additionally, large scale deformations in drives, or squeezing ground conditions in hard rock underground mines have major economic implications. In 254 rockburst cases analysed worldwide by Heal (2010), the most common component of the integrated ground support system to fail was the surface support. It has also been suggested by Hadjigeorgiou et al. (2013) that squeezing ground cannot be stopped but can be controlled by ground support which is able to “deform in order to accommodate the resulting high deformations while maintaining the integrity of the reinforced rock unit” (Potvin & Hadjigeorgiou 2008).
The Australian Centre of Geomechanics (ACG) has developed, over seven years a high energy absorption mesh (HEA Mesh) which is designed to withstand a larger amount of quasi-static and dynamic loading due to rockbursting and squeezing ground than regular weld mesh. It consists of a sheet of weld mesh reinforced with a cable around the sheet perimeter and interlocking in two ‘V’ shapes in the middle. The design was based upon the South African cable lacing method, but with the installation time of weld mesh, to combine strength and flexibility. Preliminary laboratory and field testing results indicate that the HEA Mesh included in a dynamic ground support system performs better than ground support that is commonly used currently for rockbursting and squeezing ground conditions. Underground operations have been reluctant to adopt this mesh due to lack of awareness of the product.
The literature will be used as a foundation to present laboratory and field test results of the HEA Mesh. Three case studies of Australian and European underground mining operations will be analysed forcost-benefit of incorporating HEA Mesh into their current rockburst and squeezing ground support.
Incorporation of the HEA Mesh was assessed and quantified to provide apparent cost savings in three currently operating underground mines. These study results offer a number of advantages to operations worldwide, including improved productivity and safety. In the current Australian mining climate specifically, cost savings would be extremely beneficial.
Australian Centre for Geomechanics 2008, Long Shaft Site 3 Simulated Rockburst Results, report from the Mine Seismicity and Rockburst Risk Management Project, ACG, Perth.
Hadjigeorgiou, J, Karampinos, E, Turcotte, P & Mercier-Langevin, F 2013, ‘Assessment of the influence of drift orientation on observed levels of squeezing in hard rock mines’, in Y Potvin & B Brady (eds), Proceedings of the Seventh International Symposium on Ground Support in Mining and Underground Construction, Australian Centre for Geomechanics, Perth, pp. 109-118.
Heal, D 2010, ‘Observations and Analysis of Incidences of Rockburst Damage in Underground Mines’, PhD thesis, The University of Western Australia, Perth.
Kaiser, PK, Tannant, DD, McCreath, DR & Jesenak, P 1992, ‘Rockburst Damage Assessment Procedure’, in PK Kaiser & DR McCreath (eds), Rock Support in Mining and Underground Construction, A.A. Balkema, Rotterdam, pp. 639-647.
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