Coeur Mining Inc. said Feb. 26 that the net present value of its Rochester silver-gold project in Nevada more than doubled, at a 5% discount, to US$609 million from US$280 million, according to the latest preliminary economic assessment.
With the introduction of a high-pressure grinding roll technology, the assessment also extended the mine life to 2038 from 2031 and marked a 122% increase in total pretax life-of-mine cash flows to US$955 million from US$431 million. Anticipated pretax cash flow margin was increased to 31% from the 19% posted in a technical report released in February 2017.
The company said it is still evaluating the new technology and expects to make a development decision in early 2019 with an estimated cost of about US$20 million. The company also plans to add a second high-pressure grinding roll unit in 2020.
The technology could increase Rochester's silver recoveries from 61% over 20 years to 70% in just over two years. CapEx for construction of a larger scale is expected to drop to US$351 million from US$387 million.
The new mine plan reduced the strip ratio to less than 0.4 to 1, from 0.8 to 1, as it incorporated inferred resources in the open pit. The company plans to upgrade the inferred to reserves through infill drilling over the next three years.