Planning the extraction and preparation of mineral resources

In the mineral industries, large quantities of material are extracted from natural deposits and processed into marketable mineral products. Customers demand steady supply in defined qualities, while natural resources are inhomogeneous and technical constraints restrict the solution space of feasible production programs. Linear Programming models are common to solve this problem, but they do not suffice. Zero-Or-Range conditions on production amounts and sequencing constraints for scheduling purposes make the problem NP-hard. In addition to showing this, we present a common heuristic approach and demonstrate how it is used in a system for everyday planning in an underground hard coal mine.