Core Lithium Starts Underground Mining at BP33 and Ships First Lithium Products
Core Lithium has begun underground decline development at its BP33 deposit within the Finniss Lithium Project, alongside ongoing open pit mining at Grants, and successfully shipped its first lithium products via Darwin Port.
- BP33 underground portal cut marks key operational milestone
- Underground and open pit mining to run concurrently
- First shipment of lithium fines and spodumene concentrate completed
- BP33 offers over 10 years of low-cost underground production
- Full underground production targeted by mid-2028
BP33 Portal Cut Signals Transition to Underground Mining
Core Lithium Ltd (ASX:CXO) has marked a significant step in its Finniss Lithium Project by commencing underground decline development at the BP33 deposit. The portal cut at BP33 initiates what the company describes as a long-life, low-cost underground production phase, with mine life expected to exceed 10 years and the deposit remaining open at depth. This milestone represents the early phase of Finniss’ transition from initial open pit operations to a sustained underground mining operation.
Parallel Mining Operations at Finniss
The underground development at BP33 will proceed in parallel with ongoing open pit mining at the Grants deposit, which is currently delivering early revenue streams. Grants is expected to produce approximately 780,000 to 790,000 tonnes of ore and 130,000 to 140,000 tonnes of SC5 spodumene concentrate, with ore processing slated for the September quarter and spodumene shipments commencing shortly thereafter. This dual approach aims to maintain steady production volumes as the operation scales.
First Lithium Shipment via Darwin Port
Core Lithium’s logistics chain is now fully operational, highlighted by the successful export of 20,000 tonnes of lithium fines and 5,000 tonnes of stockpiled spodumene concentrate through Darwin Port. Payment for this shipment is expected before the end of June 2026, reflecting the company's ability to effectively mobilise its mine-to-port supply chain. This shipment builds on earlier sales agreements and operational progress made at Grants and the underground development at BP33.
Contract Awards and Operational Progress
The underground mining services contract for BP33 was awarded to Develop Global Limited in May 2026, with mobilisation to site now complete. Core Lithium has also advanced civil works and portal face preparations ahead of the underground decline. The company targets first development ore from BP33 by mid-2027 and aims to reach nameplate underground production by mid-2028. The ramp-up underscores Core’s commitment to safely delivering operations on schedule and within budget.
Strategic Implications for Core Lithium
BP33 stands as a cornerstone asset for Core Lithium, supplying a majority of ore feed in the first decade of underground production. The ongoing Grants open pit provides a near-term ore source, helping to fund and support the transition underground. The company’s Managing Director, Paul Brown, emphasised the operational momentum achieved since the Final Investment Decision earlier this year, highlighting the strength of the restart strategy and the capability of the operating team.
Bottom Line?
Core Lithium’s move underground and first product shipment mark a pivotal phase in scaling Finniss, with execution now key to meeting mid-2028 production targets.
Questions in the middle?
- How will underground development timelines at BP33 hold up against operational risks?
- What impact will concurrent open pit and underground mining have on overall production costs?
- Can Core Lithium sustain lithium product shipments to maintain cash flow during ramp-up?
