PERTH (miningweekly.com) – Mineral sands developer Sheffield Resources has reported a 10% increase in the ore reserve at its Thunderbird project, in Western Australia.
Sheffield on Wednesday reported that some 68-million tonnes had been added to the Thunderbird reserve, bringing it to 748-million tonnes, grading at 11.2% heavy minerals.
The updated ore reserve included a 500 000 t increase in contained zircon, which is now estimated at 6.4-million tonnes, which Sheffield MD Bruce McFadzean said underlined the significant scale of the Thunderbird deposit.
The updated ore reserve will form the bass of an update to the bankable feasibility study (BFS) for the Thunderbird project, which is due for release in this quarter.
The BFS update is targeting a 38% increase in the ore mining rate, the deferral of the low temperature roast ilmenite circuit and an increase in zircon production, which is expected to deliver lower capital and operating costs, lower construction risk and a financially stronger project.
The increased ore reserve has increased the period of mining the higher-grade T2 ore from seven years to ten years, removing the lower grade T1 ore from the process plant feed, which increases the in-situ zircon grade in the proved category to 1.02% zircon, and reduces the tonnage of the proved category from 235-million to 219-million.
“We will preferentially mine the high grade T2 ore thereby increasing the feed grade into the processing plant. This approach supports the recent decision to defer the low temperature roast ilmenite circuit and focus on increased zircon output,” said McFadzean.