Nilpinna Drilling Yields Heavy Mineral Sands Assays Exceeding 12.5% HM

Exploration Breakthrough in the Eromanga Basin

Altitude Minerals Ltd (ASX, ATT) has delivered encouraging results from its inaugural drilling program at the Nilpinna Tenement, part of the broader Eromanga Basin Heavy Mineral Sands (HMS) Project in South Australia. The wide-spaced aircore drilling campaign, completed in September 2025, has confirmed the presence of heavy mineral sands with grades reaching up to 12.5% HM (heavy minerals), a significant milestone for this previously underexplored region.

The drilling program comprised 114 holes totaling over 4,000 meters, with 15 priority holes selected for detailed assay analysis at the Diamantina Laboratory in Perth. All these holes returned significant heavy mineral content above 1%, with valuable heavy minerals (VHM) such as ilmenite, leucoxene, rutile, and zircon identified through laboratory sachet logging. These minerals are critical components in various industrial applications, including pigments, ceramics, and titanium metal production.

Geological Context and Mineralisation

The mineralisation is hosted within the Cadna-owie Formation, a marine sequence of unconsolidated sands interpreted as a regressive strand plain. This geological setting is notable for its potential to concentrate heavy minerals in strand deposits, particularly in so-called “still stands” where sediment deposition is stable. Altitude’s technical team has identified a 20-kilometer-long paleo-shoreline ridge as a prime target for further exploration, alongside magnetic anomalies north and south of the initial drilling area.

Importantly, the heavy mineral assemblage is dominated by iron-rich minerals such as goethite and limonite, but the valuable heavy minerals constitute a meaningful proportion of the total heavy mineral content. Some drill holes exhibited VHM percentages exceeding 0.5%, which the company interprets as indicative of significant HMS accumulations warranting further investigation.

Next Steps and Strategic Outlook

Altitude Minerals plans to intensify exploration efforts in 2026, focusing on ground truthing the three priority areas identified through drilling and geophysical surveys. Ground magnetics will be employed to refine target definitions, followed by additional aircore drilling to delineate the extent and grade of mineralisation. The company’s managing director, Duncan Chessell, emphasized the strategic importance of leveraging technical expertise to unlock value in underexplored jurisdictions, noting that the Eromanga Basin represents a large, previously unrecognised exploration space for HMS.

While drilling on the Douglas Creek and Eddy tenements did not intersect significant heavy mineral sands, the Nilpinna results provide a compelling proof-of-concept for Altitude’s HMS exploration strategy. The company remains cautious, acknowledging that these are early-stage results and that further work is required to establish economic viability.

Technical consultant Ian Warland highlighted the encouraging nature of the marine sequence and the quality of the heavy mineral assemblage, underscoring the potential for shallow, higher-grade deposits. The upcoming phases of exploration will be critical in validating these early findings and advancing the project towards resource definition.