TSX-V-listed Apollo Silver Corp has reported positive results from a preliminary economic assessment (PEA) at its Calico silver project, California, in the US, with the PEA estimating an after-tax net present value (NPV) of $737-million, an after-tax internal rate of return of 25% and a payback period of three years. The PEA is based on the development of an openpit mining operation at the Waterloo deposit, feeding a conventional 8 000 t/d milling and cyanidation leach plant with an initial planned processing life of about 15 years.
