Coda Minerals Initiates Hydrogeological Drilling at Elizabeth Creek Copper-Silver Project in South Australia

Focused Hydrogeological Drilling at Windabout and Emmie Bluff Prospects

Coda Minerals has mobilised a drill rig to conduct a detailed hydrogeological assessment across two primary zones within the Elizabeth Creek Copper-Silver Project. This programme is designed to collect site-specific aquifer and groundwater data crucial for advancing the Pre-Feasibility Study. At the Windabout open-pit prospect, one production and one monitoring bore will be drilled. The Emmie Bluff underground flagship prospect will have two production and two monitoring bores drilled, totaling approximately 1,400 metres of drilling.

The production bores will enable aquifer pump testing to evaluate water flow and recharge rates, while monitoring bores will observe groundwater responses during and after testing. Coda highlighted that the collected data will directly contribute to the regional hydrogeological model under development as part of the ongoing Pre-Feasibility Study. The hydrogeological drilling is expected to take several weeks, marking a key step in the project's development.

Essential Data for Mine Dewatering and Geotechnical Engineering

Data from this hydrogeological drilling will address critical engineering and operational needs at Elizabeth Creek. It will inform dewatering and depressurisation strategies for both open-pit and underground mining, as well as underground geotechnical parameters necessary for safe mine design. Understanding the site's water balance—how water inflows, outflows, and storage interact—is fundamental to predicting mining impacts on local groundwater.

Additionally, this investigation supports Coda's environmental compliance efforts. The data will help anticipate and manage potential effects on nearby water users and groundwater-dependent ecosystems well before construction begins. The company regards this work as central to its Mining Lease Application and environmental approval process, indicating regulators will rely on this hydrogeological characterization when assessing water management and environmental safeguards. Early data collection aims to build regulatory confidence in Coda's responsible operation of the Elizabeth Creek Project.

Strategic Drilling Sequence and Engineering Integration

Coda has aligned its fieldwork with the Pre-Feasibility Study's maturity. CEO Chris Stevens noted the company is moving beyond core data collection to address specific gaps while other studies proceed concurrently. This targeted approach focuses hydrogeological drilling on identified knowledge gaps rather than broad exploration, reflecting PFS progress rather than fundamental project uncertainties.

Following the hydrogeological programme, the rig will relocate to the Oakden prospect for exploration drilling. The company plans to announce the targeting rationale for Oakden shortly. Concurrently, aquifer pump testing will be conducted to assess water flow and recharge, informing the full site water balance. If water risk is low, further work on water resources and production bore planning may be deferred to the Detailed Feasibility Study phase; if higher risk is identified, additional work could occur later this year.

Oakden Exploration and Additional Geological Prospects

After completing hydrogeological drilling at Windabout and Emmie Bluff, Coda intends to use the same rig for exploration drilling at Oakden. This programme will include approximately 5–6 RC drillholes totaling up to 400 metres. Coda has described Oakden as having "real potential to add to the Elizabeth Creek story," indicating it may provide additional mineral resources within or near the current project area. A detailed announcement on exploration targeting will precede drilling.

One monitoring bore at Emmie Bluff is located about 300 metres northwest of diamond drillhole DD25EB0038, where Coda previously reported the first copper mineralisation in the Tapley Hill Formation outside the existing Emmie Bluff resource boundary. While these bores are primarily for hydrogeological purposes and not designed as exploration holes, geological logging of cuttings and any core will be conducted. The company cautions that the previously reported mineralisation was sub-economic in thickness, these bores are not intended to test mineralisation, and there is no guarantee mineralisation will be encountered during this programme.

Overview of Elizabeth Creek Project and Asset Portfolio

Coda Minerals holds 100% ownership of the Elizabeth Creek Copper-Silver Project in South Australia, which includes multiple prospects. Emmie Bluff is the flagship underground target, while Windabout is an open-pit opportunity. The project has advanced to the Pre-Feasibility Study stage, reflecting a mature asset with defined mineral resources and a clear development path. The presence of Windabout, Emmie Bluff, and Oakden prospects indicates a portfolio strategy aimed at near-term development supported by longer-term exploration upside.

Work completed at Elizabeth Creek includes resource definition drilling, metallurgical studies, and engineering investigations to evaluate technical and economic mining viability. Recent announcements of improved copper and silver recoveries demonstrate ongoing optimisation of project economics. By focusing on a single large copper-silver asset in South Australia, Coda pursues a concentrated development strategy, dedicating capital and management resources to advance the project through feasibility and approvals toward potential construction and operations.

Advancement of Pre-Feasibility Study and Engineering Efforts

The hydrogeological drilling programme explicitly supports the ongoing Pre-Feasibility Study, a formal engineering and economic assessment that evaluates mining viability under defined assumptions about methods, processing, capital, and operating costs. Coda’s decision to conduct dedicated hydrogeological drilling prior to PFS completion highlights water management and groundwater characterization as key design drivers requiring field data.

The PFS typically includes mine planning, process design, cost estimation, and environmental analysis. Collecting hydrogeological data alongside other PFS studies addresses a critical input for mine design and operational planning. Results will inform geotechnical modelling, water balance calculations, and environmental impact assessments—standard components of a comprehensive Pre-Feasibility Study. This phased approach reflects confidence in project viability while focusing on refining design parameters and reducing technical and approval risks.

Water Management and Environmental Approval Strategy

Water availability and management are central to Coda’s development strategy for Elizabeth Creek. The hydrogeological programme aims to establish the site water balance, determining water availability for mining, required mine dewatering, and potential impacts on surrounding groundwater users. This information is crucial for mine design and regulatory approval, as South Australian environmental regulators require evidence that mining will not adversely affect regional groundwater systems and dependent ecosystems.

Coda’s early investment in hydrogeological characterization aligns with best-practice development protocols—understanding water dynamics before finalising mine design. Aquifer pump testing and water balance establishment will enable a robust hydrogeological model supporting engineering design and regulatory submissions. Depending on water risk assessment, further work on water resources and production bore planning may be deferred to the Detailed Feasibility Study phase or undertaken later this year. This adaptive strategy prioritizes capital allocation based on risk and opportunity.

Regulatory Compliance and Mining Lease Application Process

Coda has indicated that the hydrogeological investigation is integral to its Mining Lease Application and environmental approvals. Mining Lease Applications in South Australia require thorough environmental impact assessments, including effects on water resources, and demonstration of effective management and mitigation strategies. By compiling comprehensive hydrogeological data and showing detailed understanding of groundwater conditions, Coda is establishing a strong technical foundation for regulatory submissions.

The company’s focus on potential impacts to surrounding water users and groundwater-dependent ecosystems well in advance of construction reflects a proactive stakeholder engagement and risk management approach. Early hydrogeological characterization allows identification of potential conflicts or concerns before finalising engineering design, enabling adjustments to minimise impacts. This approach aligns with regulatory expectations for comprehensive baseline studies and impact assessments prior to project approval. Investing in detailed hydrogeological work during the Pre-Feasibility Study phase demonstrates Coda’s commitment to technical diligence and environmental stewardship.

Capital Efficiency and Drilling Programme Scheduling

The announcement reveals Coda’s emphasis on capital efficiency and rig utilisation. Instead of deploying separate rigs for hydrogeological and exploration drilling or allowing downtime, the company plans to use a single rig to complete hydrogeological work at Windabout and Emmie Bluff, then transition directly to exploration drilling at Oakden. This sequencing reduces demobilisation and remobilisation costs and optimizes contracted drilling capacity.

The hydrogeological programme is expected to last several weeks, followed by Oakden exploration drilling and concurrent aquifer pump testing, indicating a sustained field campaign over coming months. Follow-up work, if necessary, may occur later this year or be deferred to the Detailed Feasibility Study phase based on findings. This flexible scheduling allows Coda to adapt its development timeline according to actual data rather than fixed assumptions. Having a rig mobilised on-site also ensures readiness for any additional drilling that may arise from hydrogeological or exploration outcomes.