PERTH (miningweekly.com) – A technical refresh of the Buena Vista feasibility study has shown that the project could be moved to a 24/7 operating model and could increase its potential output from 450 000 t/y to 800 000 t/y at the same capital outlay.

ASX-listed Magnum Mining & Exploration undertook the technical refresh of the Buena Vista iron project, in Nevada, to fine-tune the 2011 feasibility study, as well as the recently announced scoping study.

While the scoping study aimed at a two-million-tonnes a-year concentrate production rate, the technical refresh focussed on accessing the highest grade resources with the goal of getting into production as quickly, and at the lowest production cost, as possible.

The recently released scoping study estimated that the project could produce 1.6-million tonnes a year of concentrate over a mine life of 25 years. The scoping study estimated a capital cost of between $182-million and $378-million and an operating cost of between $44/t and $90/t, with the internal rate of return ranging between 26% and 54%, and the net present value between $360-million and $745-million.

Meanwhile, the technical refresh stated that Buena Vista could be designed to potentially deliver an iron-ore product of more than 68% iron, based on recent test work.

Magnum said on Monday that the updated mine schedule for the technical refresh was also designed to support a 25-year mine life, similar to that in the scoping study, with a near constant grade feed to the beneficiation plant. The financial modelling supports an operation accessing higher-grade ores earlier, leaving the lower grade resource for later in the mine life, after the bulk of the capital has been repaid.

Work is currently underway to optimise the mine schedule to embrace this model and support the feed required for the designed 800 000 t/y concentrate production rate.