Thibodeau, D & Jodouin, J 2014, 'Conciliating ventilation requirements and geomechanical requirements for deep mining', in M Hudyma & Y Potvin (eds), Proceedings of the Seventh International Conference on Deep and High Stress Mining
, Australian Centre for Geomechanics, Perth, pp. 783-791.
As mines go deeper, managing heat due to the geothermal gradient, auto compression and the large diesel equipment used to achieve production is a constant battle. Ventilation requirement to cool down the work place is in constant opposition to the geomechanical constraints related to increased stress level, seismicity and rock mass failure. To minimise the energy used to push air through the deep workplaces of a mine, ventilation requires large conduits to keep friction and turbulence to a minimum and avoid undue warming of the fresh air before it reaches its destination. On the contrary, smaller openings at depth allows mines better mitigation of geomechanical risk providing improved long term stability and allowing permanent infrastructures to be closer to the ore body. Ventilation and geomechanical considerations, being the two pillars of deep mine design, are opposed to each other. This paper demonstrates how ventilation requirements and geomechanical requirements can be conciliated for deep mine design to ensure safe production.
This paper describes the basic ventilation requirement for deep mining using a hypothetical case stipulating optimum design criteria for the underground openings. Based on the ventilation requirement, a list of compromises or mitigation measures will be reviewed to improve mine design both from ventilation and a geomechanical point of view. Furthermore, a list of technical and financial impact of the ventilation and geomechanical conciliated design will also be provided.
*m and S are Hoek and Brown constant for a brittle failure criterion (Hoek & Brown 1980, 1988; Martin et al. 1999).
In order to ensure good practice in the ventilation design phase of a study, design principles must be established. Best practice mine ventilation system design is based on the following criteria:
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