Optimum cut-off grade’s calculation in open pit mines with regard to reducing the undesirable environmental impacts

Abstract

Cut-off grade – a criterion used to discriminate ore from waste – has direct impact on mineable reserves and average grade of the materials that must be processed. The most comprehensive method for determination of optimum cut-off grades in metal deposits with the goal of maximising the net present value is provided by Lane’s algorithm. Lane’s algorithm includes income and the production costs of the final product, mining, processing and refinery capacities and grade distribution of the ore deposit, but he did not consider the reclamation costs and incomes. This study provides a model for determination of cut-off grades in open-pit mines. In this model, in addition to costs associated with management and reclamation of waste dumps, tailing dam and pits, possible incomes from reclamation are also considered. Developed model has been verified by data gathered from Gol-Gohar iron mine of Iran and results indicated that there is some important improvement in mine project goal.

Keywords:

• cut-off grade
• net present value
• reclamation
• income
• cost
• iron ore mines