Hall, JW 2013, 'The hydro-geotechnical decision cycle – having mine design and planning decisions made by the right people', in PM Dight (ed.), Proceedings of the 2013 International Symposium on Slope Stability in Open Pit Mining and Civil Engineering
, Australian Centre for Geomechanics, Perth, pp. 1125-1129, https://doi.org/10.36487/ACG_rep/1308_79_Hall
The design of pit slopes where groundwater or pore pressure has some influence on slope stability requires two key mining disciplines to be applied; geotechnical engineering and hydrogeology. These two broad disciplines also cover structural geology, geomechanical, groundwater and hydro-mechanical coupled modelling and surface water hydrology. These are all specialist disciplines with specific education and training requirements. With experience, we develop an understanding of, and can even become experts in, these other disciplines. That is, we become adept practitioners in the overall slope design and mine planning process. However, this takes time.
What of our site based mine planning staff, who are mostly young and still developing their overall mine planning skills? It is not uncommon for our site based geotechnical engineer (or hydrogeologist) to have a whole range of duties assigned to them, many of which are outside their current skill and experience levels. Is this fair? Can it result in practical, cost effective or safe slope designs? It can, but only when our site staff are provided with adequate technical support from the cross disciplines.
So, what does this support look like, and when do we need to provide it? A useful way to assess this is to consider what I call the Hydro-Geotechnical Decision Cycle. This is simple process whereby the geotechnical engineers does what they are good at (and qualified to do) and the hydrogeologists do the same, so that together they can develop the appropriate mine planning solutions through an iterative process of data collection, analysis, design, implementation and feedback. Sound familiar? This is the same as a Continuous Improvement cycle (i.e. plan-do-check-act).
This paper develops the concept of the Hydro-Geotechnical Decision Cycle and presents examples of where it can help when applied and where it has gone wrong when it has not been applied.