Jindalee Lithium Drills Into One of the US’s Largest Lithium Deposits
Key Takeaways
- Phase 1 infill drilling has commenced at the McDermitt Lithium Project in southeast Oregon, with both Reverse Circulation and diamond drill rigs now operating on site.
- The 2026 campaign targets approximately one-third of the up to 100 approved Phase 1 sites, with program completion expected by end of November 2026 and first results anticipated in Q1 2027.
- The drilling is specifically designed to upgrade portions of the current Mineral Resource Estimate from Inferred to Indicated classification, strengthening the foundation for the McDermitt Feasibility Study.
- McDermitt holds a total resource of 21.5 Mt LCE across 3,000 Mt of material, making it one of the largest lithium deposits in the Western world, 100% owned by Jindalee with unencumbered offtake rights.
- The US Department of Energy has been noted among government agencies engaged with the project, reflecting McDermitt's strategic relevance to US domestic critical minerals supply — though no committed funding has been disclosed.
Drilling gets underway at one of the US’s largest lithium deposits
Phase 1 infill drilling has commenced at the McDermitt Lithium Project in southeast Oregon, marking a significant operational milestone for Jindalee Lithium (ASX: JLL). The program follows the Bureau of Land Management’s (BLM) approval of the Exploration Plan of Operations (EPO) in December 2025 and the subsequent lifting of fire restrictions in September 2026, with boots now firmly on the ground.
The McDermitt drilling permits cleared their final regulatory hurdle in August 2026, with BLM’s Exploration Plan of Operations approval in December 2025 setting the foundation and fire restriction lifts completing the path to mobilisation.
Both Reverse Circulation (RC) and diamond drill rigs are currently operating on site at the central part of the deposit. The RC drilling is collecting hydrogeological data, while the diamond rigs are obtaining fresh core for geotechnical studies and metallurgical testwork. Phase 1 has up to 100 drill sites approved as part of a broader staged 168-site program, with the 2026 campaign targeting approximately one-third of those Phase 1 sites. The program is expected to complete by the end of November 2026, with first results anticipated in Q1 2027.
Ian Rodger, Managing Director & CEO
“We are very pleased to advise that the Phase 1 drilling program is now underway following the recent lifting of fire restrictions. We are taking additional fire-safety precautions throughout the program, and we remain committed to operating responsibly. This program will provide critical data to feed into the McDermitt Feasibility Study and we look forward to providing further updates as results are received.”
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What is infill drilling and why does it matter for resource classification?
Infill drilling involves drilling additional holes within an already-identified deposit at tighter spacing than the original exploration program. The tighter the drill pattern, the better the geological picture the company builds, and the more confidence geologists can assign to their resource estimates.
That confidence level matters because Mineral Resources are classified into categories based on data density and geological understanding. An Inferred Resource is the lowest confidence category, based on limited data with significant geological uncertainty. An Indicated Resource carries higher confidence, meaning the geology is better understood and the estimate is more reliable.
Why does this distinction matter for investors? Feasibility studies, which assess whether a project can be built and operated profitably, carry substantially more weight when they are underpinned by Indicated rather than Inferred Resources. The McDermitt Phase 1 program is specifically designed to support a potential upgrade in classification of portions of the current Mineral Resource Estimate (MRE) from Inferred to Indicated, which would strengthen the foundation of the Feasibility Study.
McDermitt’s resource scale in context
McDermitt is described by Jindalee as one of the largest lithium resources in the US and of global significance, a characterisation supported by the November 2024 Pre-Feasibility Study (PFS). The project is 100% owned by Jindalee with unencumbered offtake rights, meaning no third party holds a claim over where the lithium can be sold. In the current environment, where the US is actively seeking to secure domestic critical minerals supply, that ownership structure is a meaningful strategic differentiator.
The 2023 MRE, which underpins the current development work, is presented below.
| Resource Category | Tonnage (Mt) | Li Grade (ppm) | LCE (Mt) | Cut-off Grade (ppm Li) |
|---|---|---|---|---|
| Indicated Resource | 1,470 | 1,420 | 11.1 | 1,000 |
| Inferred Resource | 1,540 | 1,270 | 10.4 | |
| Indicated + Inferred Total | 3,000 | 1,340 | 21.5 |
Source: Jindalee Lithium ASX announcement, 27 February 2023. Note: totals may vary due to rounding.
At 21.5 Mt of lithium carbonate equivalent (LCE) in total, McDermitt’s scale places it among the most significant lithium deposits in the Western world. Jindalee’s 100% ownership and unencumbered offtake rights position the company to supply US domestic demand for battery-grade lithium without the constraints that partial ownership or pre-committed offtake arrangements typically impose.
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What comes next — the path to feasibility
The 2026 drill program feeds into a sequenced development pathway with several near-term milestones:
- 2026 drill program completion — targeted by the end of November 2026, covering approximately one-third of the up to 100 Phase 1 approved sites.
- First Phase 1 results — expected Q1 2027, which will begin translating drilling activity into geological and hydrogeological data.
- Remaining Phase 1 sites — the balance of up to 100 approved sites is to be drilled in subsequent stages beyond the 2026 campaign.
- Data feeds into the McDermitt Feasibility Study — the announcement does not disclose a specific Feasibility Study completion date.
The broader staged program encompasses 168 total sites in total, with Phase 1 approved at up to 100 of those. The 2026 campaign represents the opening chapter of what is a multi-stage data collection effort. The US Department of Energy has been noted as among the government agencies engaged with the project, reflecting McDermitt’s relevance to US domestic energy security, though no committed funding from that engagement has been disclosed.
For investors, the significance of this milestone is straightforward. Regulatory approvals are necessary but not sufficient to advance a lithium project. What converts those approvals into a credible development case is data, the kind that only comes from the ground. The Phase 1 program is now generating that data, with results expected to feed directly into the Feasibility Study that will define McDermitt’s development economics.
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