Simultaneous Production Scheduling and Waste Management Optimization for an Oil Sands Application

Mine planning for oil sands involves the integration of waste management into the long term production planning process. This ensures that while ore is provided for the processing plant, sufficient in-pit tailings containment areas are made available as dedicated disposal areas for backfilling. This enables the creation of a trafficable landscape at the earliest opportunity to facilitate progressive reclamation. Apart from being a regulatory requirement, this integration impacts directly on the profitability and sustainability of oil sands mining operations. This paper introduces a mixed integer linear programming mine planning framework that seeks to simultaneously determine the production schedule, dyke construction schedule and the backfilling schedule. Different waste management strategies were also investigated. The model generated a practical, smooth and uniform schedule for ore, dyke material and backfilling activities. The results show that for the case studies considered, increasing the number of in-pit tailings cells reduces the net present value of the mine as a result of a reduced operational flexibility. However, this strategy makes in-pit tailings storage areas available earlier in the mine life, and ensures an efficient use of in-pit storage areas required for sustainable operations.