The preliminary economic assessment for Defense Metals' rare earth Wicheeda mine in British Columbia has a net present value of C$512 million at an 8% discount rate, with a payback period of five years.

The mine will have a post-tax internal rate of return of 16%, with initial capital costs estimated at C$461 million. Operating costs over the 16-year mine life average C$137 million per year.

Defense Metals plans to process an average of 1.8 million tonnes per annum, with average annual rare earth oxides production of 25,423 tonnes.

The company plans to sell REOs to market directly for the first four years, and then feed a project hydrometallurgical plant in the fifth year.

Mined materials will be processed in a flotation concentrator, and will then be further processed at the hydrometallurgical plant.

Defense Metals is testing the hydrometallurgical process, and plans a pilot plant demonstration of the selected process.

A tailings pond of 20 million cubic meters will need to be constructed to manage water runoff and waste materials. Defense Metals is still in the process of deciding the location of the tailings storage facility.