Groundwater Flow Models in Open Pit Mining: Can We Do Better?

Abstract

When do issues of complexity outweigh the practicality of experience-based judgement? Prior to the arrival of computer-generated flow models, heurism and the application of simple, practical, tried-and-proven techniques resonated at the heart of any mining operation. With the current reliance on overly designed and time-intensive numerical models, are we meeting what the miner needs? As hydrogeological practitioners in the mining industry, we need to be adaptive and possess tools that allow ‘on the run decision-making’ that can, quickly and effectively, meet the time frames required by the miner, at each stage of mine development. A more appropriate strategy would be to adopt a ‘right tool for the job’ approach using models that target specific areas or stages of mine development. This will potentially result in multiple models that overlap in time and space. Furthermore, in the process of selecting an appropriate model, the hydrogeologist needs to be cognisant of the levels in accuracy required from the model; it should be commensurate with the detail built into the conceptual model. This should guide selection of the model solution and the complexity of the model. The approach is discussed, using an actively dewatered open pit mine and the application of the analytical superposition modelling method as an example.