PERTH (miningweekly.com) – Potash developer Highfield Resources has doubled the mine life of its Muga project, in Spain, on the back of an optimisation study.

A previously completed definitive feasibility study (DFS) into the Muga project estimated a capital investment of $256-million would be required to deliver 1.12-million tonnes a year of granular potash over 24 years.

The optimisation study has now increased the mine life to 47 years at a production rate of just over one-million tonnes of granular potash a year, with Highfield saying on Tuesday that significant upside potential remained from substantial exploration targets.

The project’s net present value had also increased from $1.42-billion to $1.46-billion, while the Phase 1 capital expenditure increased slightly from €249-million to €267-million.

“We have had a very productive six-month period, taking our Muga mine from a DFS to a mine ready to be built and operated,” said MD Anthony Hall.

“Our initiatives have resulted in a doubling of mine life, as well as a mine which will be significantly better to operate long term. We have factored in expansion to our Muga mine design and also have further mine life potential that sits in our substantial Muga project exploration target.”

The optimisation work included altering the mine plan to include an additional sylvinite stream, resulting in the increased mine life, as well as electing to use a combination of continuous miners and road headers to increase productivity in production and infrastructure development.

The optimisation study also increased the number of main infrastructure galleries in the mine plan from one to three, to reduce the ramp-up risk and increase likely operational efficiency, and increased the size of the underground conveyor belt system, to cater for an increase in underground tonnage, to enable better expansion options.

The mine and process plant have also been altered to deliver a constant 90 000 t of granular potash material a month for the balance of the revised mine life, and increase the size and flexibility of the process plant to deal with higher throughput material.

Hall said the company also had contracts ready to be executed for over 25% of the direct costs of the mine.

“This pricing is below budget without any contingency, which suggests we are well on track to delivering the mine within our capex estimate.”