Underground planning at Stillwater Mining Company

As part of a new expansion effort, Stillwater Mining Company needed a tool for analyzing development and production scenarios is a new area of an underground platinum and palladium mine in Stillwater, Montana. We developed a large mixed-integer programming model that takes as input the planned mine layout, projected ore quality, and projected costs for basic mining activities, and produces as output a near-optimal schedule of activities that maximizes discounted ore revenue over a given planning horizon. We then used this model to evaluate various planning scenarios and make recommendations about development and production in this new area.