Development and analysis of a methodology to generate operational open-pit mine ramp designs automatically

critical step in planning an open-pit operation corresponds to the design of ramps required to access the different sectors and levels. This design is very complicated because the ramps affect the excavation’s shape, therefore, its economic value. Thus, planners generate contours to be used as reference for the design. These contours (or equivalently the volume they contain) are generated by mathematical models that aim to optimize the economic value that is contained in them. Then, through Computer-Aided Design software, planners manually draw the operational design that, hopefully, retrieves as much value as possible from the reference volumes and is operationally feasible. Unfortunately, this manual process does not ensure the quality of the design, leading to results that are not optimal and are highly dependent on the engineer’s expertise. This article presents a methodology that starts from the same reference volume that the planner uses to generate a mine design automatically. It works in two steps. Firstly, it uses integer programming to generate a new discretized contour but containing enough space for ramps. Secondly, it utilizes a computer algorithm to transform the discretized profile into an operational pit design that complies with the mine design’s geometrical constraints. To study the proposed methodology’s applicability, we considered three cases with their corresponding reference pushbacks and used our approach to create 15 different operational designs (in total). In two of the three cases, the methodology generated profiles that were, at worst, within less than 2% deviation in value and tonnage. In the third case, the loss in economic value was more than 11% ; however, this performance was equivalent to a manual design produced by an engineer.