PERTH (miningweekly.com) – A revised feasibility study into the Dolphin tungsten project, in Tasmania, has increased the project’s net present value by 65%, from A$146-million to A$241-million, with the addition of an underground operation.

ASX-listed King Island Scheelite on Wednesday also reported that the operational life of the project has been extended from 8 years to 14 years.

“The King Island Scheelite team has continued to successfully optimise and de-risk its 100% owned Dolphin tungsten project, both technically and commercially. As part of this process, we commissioned independent consultants to design an underground mine beyond the proposed opencut limits, estimate associated capital and operating costs, and revise the financial model to reflect the impact of the underground operation,” said chairperson Johann Jacobs.

“At the same time, we deemed it appropriate to also incorporate changes to the mineral processing flowsheet and operating parameters derived from recent metallurgical testwork.

“The significantly improved financial performance forecast bears testimony to our objective of optimising and de-risking the operation. Our key next steps are to secure an appropriate balance of debt and equity funding for the redevelopment of the Dolphin project,” Jacobs added.

A previously completed economic analysis of the Dolphin project estimated that some A$65-million would need to be invested to bring the opencut operation into production to produce 2 000 t/y of tungsten over an eight-year mine life.

The updated feasibility study has estimated a start-up capital cost of A$72.1-million to develop the Dolphin project, with life-of-mine capital estimated at A$129.2-million, placing capital cost for the operation at A$40/t of tungsten produced.

The project’s pre tax net present value has been estimated at A$241-million, with an internal rate of return of 43%, and a pay-back period of just over two years.

Average life of mine costs for the opencut operation has been estimated at A$126/t and for the underground operation at A$134/t.