Polymet feasible as open pit, says study

A final feasibility study says the NorthMet copper-nickel deposit in Minnesota has positive economics as a 29,000-tonne-per-day operation.

Owner PolyMet Mining (POM-V, PLM-X) commissioned the study, by Bateman Engineering, to allow final financing for the project. It now plans to start construction in 2008.

The study said an open pit mine on a reserve of 165 million tonnes grading 0.31% copper, 0.09% nickel, 0.008% cobalt, 0.28 gram palladium, 0.08 gram platinum and 0.04 gram gold per tonne could be put into production at a capital cost of US$312 million. Operating cost, considering all metals, would be US$1,785 per tonne (US81 per lb.) for copper, US$6,260 per tonne (US$2.84 per lb.) for nickel, US$113 per oz. for palladium, US$477 per oz. for platinum and US$239 per oz. for gold.

The project would use the large Erie plant, which PolyMet acquired from steel producer Cleveland Cliffs, adding hydrometallurgical circuits downstream.

Models based on three-year average prices for the commodities the mine would produce showed an internal rate of return of 26.7% and a net present value of US$595 million, based on a 7.5% discount rate.