Castle Minerals (ASX: CDT) has taken a decisive step into one of West Africa’s most prolific gold provinces, signing a binding terms sheet to acquire a 90% stake in the Nielle gold project in northern Cote d’Ivoire. The Australian-listed explorer says the deal anchors a refreshed West African strategy and gives it direct exposure to the Senoufo greenstone belt, part of the broader Birimian system that hosts many of the region’s largest gold mines. Shares in CDT rose sharply on the announcement, with public reporting noting a single-session gain of around 34% to about A$0.067.

The transaction shifts CDT’s primary exploration focus away from neighbouring Ghana and onto a 212-square-kilometre tenement application that public reporting describes as sitting on highly prospective Birimian-aged geology. The location, around 50 kilometres north of the former Barrick Gold-operated Tongon mine, places Nielle in proximity to a system that has historically produced about five million ounces of gold, according to publicly available reports.

What Castle Minerals announced

According to the source brief and corroborating reporting, Castle Minerals has secured a 90% economic interest in the Nielle project via a binding terms sheet. The company says it intends to fast-track the asset towards a maiden mineral resource estimate, and is in advanced discussions to acquire the underlying historical data package generated by previous operators.

CDT plans to use that data to complete a detailed technical review and design a targeted infill and step-out drilling campaign. The specific commercial terms of the Acquisition, beyond the 90% interest, were not detailed in the materials reviewed and should be checked against the company’s ASX announcement and prospectus disclosures.

Inside the Nielle project

Nielle is located in the northern part of Cote d’Ivoire, within the Senoufo greenstone belt — a structural corridor that has yielded multi-million-ounce gold discoveries across West Africa. Public reporting indicates that previous operators including Resolute Mining and Corvette CIV SARL completed historical exploration on the property, identifying multiple shallow, high-grade gold intercepts across more than one kilometre of drilled strike. The mineralised corridor is reported to extend across approximately 4.5 kilometres.

For investors familiar with the Birimian system, the geological pedigree of the Senoufo belt is a key part of the story. The Birimian rocks of West Africa host most of the region’s producing gold mines and are characterised by greenstone sequences intruded by granitoid bodies, which together create structural and chemical traps for gold mineralisation.

Project context: the Tongon connection

The proximity to the former Barrick Gold-operated Tongon mine is a notable contextual point but is not a guarantee of similar outcomes. The Tongon mine, according to public reporting, produced around five million ounces of gold over its operating life. For Castle Minerals, the relevance of that historical production is geological: it demonstrates the endowment of the broader belt rather than predicting outcomes at Nielle specifically.

Why Cote d’Ivoire — and why now

Cote d’Ivoire has emerged as one of the more active gold-exploration jurisdictions in West Africa over the past decade. The country has a relatively well-developed mining code, an established permitting pathway and a growing roster of foreign operators — features that have drawn Capital away from less stable parts of the region. CDT’s pivot reflects this broader Rebalancing of West African exploration activity.

Gold prices have remained firm through 2025 and into 2026, supported by central-bank buying and persistent macroeconomic uncertainty. While CDT did not link the acquisition directly to Commodity-price assumptions in the materials reviewed, the broader pricing backdrop has encouraged junior explorers to expand higher-grade projects in tier-one and tier-two gold jurisdictions.

How the market reacted

Public reporting indicates CDT shares spiked on the announcement, with kalkine.com.au and other outlets noting an intraday rally of roughly 34% to A$0.067 on 19 May 2026. Short-term share-price moves on early-stage exploration news can be volatile and are not necessarily reflective of underlying project value; investors should assess the announcement in the context of Liquidity and the company’s overall Market Capitalisation.

Funding and next steps

The materials reviewed do not disclose a specific budget for the Nielle work program, nor do they outline whether the project will require additional Equity or Debt funding. According to the source brief, Castle’s priority is to acquire and review the historical data package, design a drilling campaign and progress towards a maiden resource. Investors should look to the company’s upcoming quarterly cash-flow report and any associated capital-raising disclosures for clarity on the funding pathway. This detail is not disclosed in the source brief and should be verified on ASX announcements.

Why it matters

For ASX small-cap investors, the Nielle deal repositions Castle Minerals as a West African gold story with direct exposure to a recognised greenstone belt and within trucking distance of a former major mine. The acquisition shortens the company’s narrative arc from grassroots exploration to data-driven, near-term drill targeting.

For the broader market, the transaction is another data point in the rotation of junior capital towards Cote d’Ivoire and away from less stable parts of West Africa. It also illustrates how mid-cap and junior explorers are increasingly looking for projects with credible historical data sets that can support a fast pathway to a maiden resource.

Key facts

  • Company: Castle Minerals Limited (ASX: CDT).
  • Transaction: binding terms sheet for a 90% interest in the Nielle gold project.
  • Location: northern Cote d’Ivoire, Senoufo greenstone belt, within the broader Birimian gold province.
  • Tenement: 212-square-kilometre tenement application, according to public reporting.
  • Geology: shallow, high-grade gold intercepts reported across a 4.5km mineralised corridor; more than 1km of drilled strike from previous work.
  • Proximity: approximately 50km north of the former Barrick-operated Tongon mine, which produced around 5Moz historically.
  • Previous operators: Resolute Mining and Corvette CIV SARL, per public reporting.
  • Next steps: acquire historical data package, technical review, infill and step-out drilling, targeted maiden mineral resource estimate.
  • Market response: shares rose around 34% to about A$0.067 on the announcement day.
  • Commercial terms beyond the 90% interest: not disclosed in the source brief — verify on ASX announcement.

What investors should watch next

The first checkpoints will be the announcement of the historical data package transfer and the release of CDT’s preliminary technical review. Once that work is complete, investors should expect a drill plan with hole counts, depths and target prospects.

The pace at which Castle progresses environmental, social and permitting approvals in Cote d’Ivoire will be a meaningful indicator. Investors should also watch for any capital raising tied to the new work program, as well as updates on whether the tenement application converts to a granted permit — a step that is essential before on-ground drilling can begin.

Balanced risk view

Exploration-stage gold projects carry significant geological and execution risk. Historical results referenced in the source brief were generated by previous operators and have not yet been independently verified by Castle Minerals through a JORC-compliant resource statement; investors should treat the 4.5km mineralised corridor as a target rather than a defined resource.

West African jurisdictional risk remains a relevant consideration. Cote d’Ivoire is considered comparatively stable but is not immune from political, regulatory or security pressures. Currency Volatility, tax regime changes and changes to mining codes can materially affect project Economics.

Funding risk is also relevant. Junior explorers regularly need to raise capital to advance drilling, and any future Placement could dilute existing holders. Commodity-price risk applies; gold has been firm but is cyclical.