Castile Resources Surges Rover 1 Mineral Inventory Amid Bismuth Supply Crunch

Resource Growth and Market Context

Castile Resources Limited has unveiled a significant uplift in its mineral resource estimates for the Rover 1 Project in the Northern Territory. The October 2025 update shows an 8% increase in gold to 341,300 ounces and a 17% rise in copper to 97,400 tonnes. Notably, bismuth; a critical metal with growing strategic importance; has surged by 51% to 8,900 tonnes, alongside increases in cobalt and magnetite.

This resource expansion is timely, as Castile integrates these figures into its ongoing Bankable Feasibility Study (BFS), reflecting current commodity prices that have risen sharply since the 2022 Pre-Feasibility Study. The company’s decision to lower the cut-off grade to 1.0g/t gold equivalent underscores confidence in the project's economic viability amid a bullish metals market.

Bismuth – A Strategic By-Product in Focus

Castile is actively pursuing a downstream production pathway for bismuth, partnering with an offshore producer to refine the metal to 99.99% purity. This move comes as China, which dominates 83% of global refined bismuth production, has imposed export controls that have disrupted supply chains worldwide. Bismuth’s unique anti-magnetic properties make it indispensable in aerospace, defense, and military applications, including China’s guided missile program, further tightening availability.

Adding to the metal’s strategic allure, researchers at Peking University have announced a breakthrough in bismuth-based microchips that outperform silicon chips by 40% in speed and 10% in energy efficiency. While commercial production remains in development, this innovation could escalate demand and supply pressures, positioning Castile’s bismuth resources as increasingly valuable.

Exploration and Development Progress

Exploration efforts at Rover continue to advance with sophisticated geophysical techniques. A downhole magnetic survey at Pathfinder 38 has identified promising magnetic sources indicative of mineralisation, while passive seismic surveys are being deployed to refine target areas ahead of the wet season. These initiatives aim to unlock further resource potential and support the BFS.

On the corporate front, Castile maintains a solid cash balance of $3.16 million as of September 30, 2025, with exploration expenditure of $481,000 during the quarter. The company is also progressing environmental impact assessments, with submissions planned for the Northern Territory Environmental Protection Authority, reflecting a methodical approach to project development and regulatory compliance.

Strategic Partnerships and Market Engagement

Castile’s engagement extends beyond exploration, with the Managing Director presenting at international forums such as the Critical Minerals QUAD Conference and the Japan–Australia Economic Security Symposium. These platforms underscore the company’s intent to position itself within diversified supply chains amid geopolitical shifts affecting critical minerals.

Negotiations with potential offshore partners for bismuth refining and broader downstream synergies are ongoing, highlighting a strategic focus on maximising value from by-products in a volatile market environment.