Integrating geological uncertainty into planning and modelling for modern and efficient dewatering concepts in large surface mines

Abstract

The dewatering of subsurface unconsolidated rock strata is a critical prerequisite for many mining operations. The uncertainty in knowledge about the aquifer geometry is critical for both, the planning of directional dewatering drilling and the hydrological planning. This contribution focuses on investigating the influence of geological uncertainty on modern mining-related dewatering measures, namely horizontal directional dewatering wells. The traditional approach of drilling, planning and groundwater modelling on the basis of interpolated geological models is extended to integrate geological uncertainty. Using conditional simulation allows for more robust decisions in planning and subsequently increased efficiency. A case study in a large open pit operation demonstrates the benefit of using such methods. For a specified level of confidence, proposed methods provide a means of determining the number of samples required for the optimal placement of the filter section. The results also provide the means of quantifying uncertainty in predicting filter-well output.