Canadian Mining Journal


COPPER: Excelsior files updated PFS for Gunnison in situ project

ARIZONA – Excelsior Mining Corp. of Vancouver has filed an updated prefeasibility study for its Gunnison in situ copper development project 100 km southeast of Tucson. The update was done after Excelsior acquired the adjacent Johnson Camp copper mine and its SX/EW plant in 2015.

The PFS put the pre-tax net present value at US$1.2 billion and after tax at US$829 million with a 7.5% discount rate and a life of mine copper price of US$2.75/lb. The internal rate of return will be 57.9% pre-tax and 45.8% post tax. Payback for the initial capital outlay will be 1.8 years pre-tax or 2.6 years after tax.

Excelsior is planning initial capital costs of US$45.9 million to produce copper at an all-in cost of US$1.24/lb over the 27-year life of the project. Initial production will be 25 million lb of copper cathode per year, using the Johnson facilities. Expansion will begin immediately toward 75 million lb/year and then 120 million lb/year. The third phase will also see the construction of an acid plant.

The updated Gunnison PFS technical report is available at