Overview: A preliminary evaluation has been carried out for the commercial potential to treat Sudbury pyrrhotite tailings. The evaluation is based on available test results carried out Vale, and feeding these results into a quantifiable detailed energy balance and process model. The results show:
- 55% IRR for any feed grade >0.8% Ni, using conservative metal prices of $5/lb Ni, $15/lb Co, $1.50/lb Cu and $850/oz for combined PGM (~5:1 Pt:Pd ratio).
- If PGMs are recovered and are present (at a level of 2 g/t per indicated from existing analyses), then the payback period is less than two years on a capital investment of $20 million for a modular plant treating 200 tonnes/day. For a plant treating 5 tpd, the capital outlay would be $5 million, but with the same payback period.
- The treatment recovery offers the ability to sell high purity hematite and elemental sulphur, which both add significantly to the overall IRR.
- The process generates off grid excess clean power, which can be sold into the grid.