Defense Metals (TSXV: DEFN) has completed the second phase of pilot plant tests on samples from its wholly owned Wicheeda rare earth element (REE) project 80 km northeast of Prince George, BC, and is moving forward with a preliminary feasibility study. The PFS is to be complete during the first half of 2024.
The phase 2 hydrometallurgical test included operating the pilot-scale hydrometallurgical plant at SGS Canada in Lakefield, Ontario, for 10 days. The tests were complete on May 3, 2023, after processing 370 km of flotation concentrate produced in September 2020.
The results of the second phase validated earlier work done. The recovery rate of praseodymium and neodymium from the acid-bake caline was more than 90%.
The mixed REE product produced during phase 2 was markedly higher in purity that of phase 1 because of a change to oxalate precipitation.
The 2021 Wicheeda REE project preliminary economic assessment (PEA) outlined a project with an after-tax net present value (8% discount) of C$517 million and an 18% internal rate of return. The PEA contemplated open pit mining providing a 1.8 million t/y mill throughput producing an average of 25,423 tonnes of rare earth oxides annually over a 16-year mine life.
A phase 1 initial pit strip ratio of 0.63:1 (waste/mill feed) would yield rapid access to higher grade surface mineralization in year 1 and payback of C$440 million initial capital within 5 years.