ABSTRACT
Discrete fracture network (DFN) modelling is a state-of-the-art stochastic technique that allows engineers and geologists to provide estimates of the potential rock discontinuity systems within a rockmass that can be acquired through geological mapping of rockmass exposures, boreholes etc. The development of such discontinuity geometry models can provide useful insights in terms of the anticipated rockmass behaviour during excavation as well as assist in determining/optimizing the required support measures to achieve a safe and efficient shaft construction. In this paper DFN modelling has been utilized as a means to assess the applicability of shaft sinking within blocky rockmasses. The implemented workflow aims to assess the potential block size to be encountered in situ based on discontinuity data collected from available rock exposures or boreholes which can be used to feed the decision-making process of the appropriate boring technique and equipment, as well as the adjustments required to provide the necessary support during shaft sinking depending on the unstable block size. A practical example using geo-data from a deep shaft at Lockwood Beck for the Anglo-American North Yorkshire Polyhalite project in the UK will be used to demonstrate the value of the method and its influence on Blind Shaft sinking.
