What is the optimal cutoff surface for ore bodies with more than one mineral?
Adriana Piazza
, , Lewis Ntaimo
2022, Operations Research Letters, 50(2), pp.137-144
Mining
Cutoff grade
Multiple minerals
Calculus of variations
Résumé
In mine planning problems, cutoff grade optimization defines a threshold at every time period such that material above this value is processed, and the rest is considered waste. In orebodies with multiple minerals, which occur in practice, the natural extension is to consider a cutoff surface. We show that in two dimensions the optimal solution is a line, and in n dimensions it is a hyperplane.