Thunderbird output surges as Sheffield advances debt standstill talks

Thunderbird reaches a quarterly production record

Sheffield Resources Limited (ASX:SFX) pushed Thunderbird through a stronger September quarter, mining 3.4 million tonnes of ore and producing 245,982 dry metric tonnes of concentrate. Ore mined reached a new quarterly record as the Kimberley Mineral Sands joint venture continued implementing its recovery plan, including the operation of its dozer mining unit.

Total shipments rose to 234,177 tonnes, including 177,732 tonnes of ilmenite and 56,445 tonnes of zircon. Zircon shipments were approximately double the June quarter, while the realised zircon price rose 8% to US$610 a tonne. Sheffield said Chinese zircon market conditions improved through much of the quarter before softening late in the period.

Higher volumes reduce Thunderbird’s unit costs

The improvement extends the operational trend captured in Sheffield’s earlier Thunderbird production gains, although the mine still faces the practical constraints of inventory, pricing and funding. Concentrate production increased to about 246,000 tonnes from 205,400 tonnes in June, while the rougher head feed heavy-mineral grade eased to 20.7% from 22.6%.

Underlying C1 cash costs fell to A$217 per tonne produced from A$261 per tonne in the prior quarter. Excluding inventory movement, costs declined to A$223 per tonne, with mining and logistics costs both lower on the larger production base. Diesel prices remain a drag, adding approximately A$2 million a quarter to operating costs, according to the company.

Lenders extend relief while standstill remains unresolved

The more consequential issue sits on the balance sheet of KMS, which Sheffield owns equally with Yansteel. KMS and its senior lenders, Northern Australia Infrastructure Facility and Sheng Feng, agreed further waivers and deferrals covering interest and principal obligations from December 2025 through September 2026, alongside covenant waivers.

The arrangement buys time for negotiations on a proposed standstill that would defer KMS debt obligations until 30 June 2027. Sheffield’s latest update follows the September lender repayment relief, but the company again cautioned that there is no certainty the standstill or any broader amendment to the senior secured facilities will be completed. Sheffield and Yansteel’s Australian subsidiary remain sponsors and guarantors of those facilities.

Cash generation and December targets remain the test

On a 100% basis, Thunderbird generated net operating cash inflows of A$0.2 million during the quarter, but ended with only A$2.1 million of cash after capital expenditure and lease repayments. Sheffield itself reported unaudited cash reserves of approximately A$3.4 million at quarter end and corporate operating cash use of A$588,000 in its Appendix 5B.

For the December quarter, Sheffield expects 3.0 million to 3.4 million tonnes of ore mined, 175,000 to 200,000 tonnes of ilmenite concentrate and 45,000 to 55,000 tonnes of zircon concentrate. C1 cash costs are forecast at A$220 to A$230 per tonne, while zircon pricing is expected to remain broadly in line with September. The South Atlantic project remains secondary: its pre-feasibility study was completed, but Sheffield did not release the results because the study did not meet JORC Code 2012 requirements, particularly around ore reserves.