Innovative criteria for economical exploitation of ornamental deposits applied the cut-off grade concept(Article)

An innovative methodology and mathematical model is developed to determine the cut-off grade of ornamental stone exploitation called cut-off quality, based on the balance between the present value and production process cost. These methodology and model is validated with excellent results in nepheline syenite quarry located in complex alkaline Monchique, Portugal. © 2010 Springer Science + Business Media, Inc.