Gray, I 2024, 'Dealing with groundwater in underground mining', in P Andrieux & D Cumming-Potvin (eds), Deep Mining 2024: Proceedings of the 10th International Conference on Deep and High Stress Mining, pp. 1433-1452, https://doi.org/10.36487/ACG_repo/2465_94
(https://papers.acg.uwa.edu.au/p/2465_94_Gray/)
Abstract: This paper examines the process of dealing with water in underground workings, with an emphasis on doing this before flooding inflows are encountered. To do this, suitable drilling and test processes that enable the nature and magnitude of the problem to be understood are discussed. These include testing from surface and from underground. The suitable test processes involve transient analysis techniques taken from the oil and gas industry and applied in boreholes drilled from the surface or underground. These techniques enable the pressure of the water and the permeability to be established along with characteristic fracture widths. They include forms of drill stem tests (DSTs) and diagnostic fracture injection test (DFIT) procedures common in petroleum but rarely used in mining. The latter enables the fracture opening and closure pressures to be determined. The result of the testwork is an understanding of the rock mass and its fluid connections.
Armed with this information, scenarios to deal with water inflow are considered. These include the use of very high pressure, high flow rate grout pumping systems, which can be used to pump cement to seal off working areas, particularly during development. These pumping systems are essentially the hydraulic fracturing pumps used in the petroleum industry. Their use is to open fractures at pressures higher than the rock stress and to force grout into these.
In many cases grout sealing is not appropriate and the paper considers drainage options for these. These options include directional drilling. Here the flow rates and total stored fluid volume are important considerations. 

Keywords: groundwater, testing, control, grouting, drainage, hydrofracturing, directional drilling