How Did Yari Minerals Nearly Double Its Rolleston South Coal Resource?

Resource Expansion Through Data Integration

Yari Minerals Limited (ASX – YAR) has delivered a striking boost to its Rolleston South Coal Project in Queensland’s Bowen Basin, announcing a 91.3% increase in its JORC (2012) Inferred Coal Resource. The resource estimate has surged from 78.9 million tonnes to 151 million tonnes, a leap achieved by integrating previously untapped open-source data from two coal seam gas wells drilled by State Gas in 2021. This approach allowed Yari to expand its geological model without incurring additional drilling costs, underscoring the company’s strategic focus on data-driven resource optimisation.

Geological Advances and Modelling Enhancements

The updated resource model incorporates data from 21 boreholes, including the two new coal seam gas wells, and employs advanced interpretation software alongside seismic data to refine seam continuity and thickness estimates. Notably, the modelling utilised the Datamine Minescape system with a reduced buffer zone for improved accuracy and excluded groundwater bores to enhance reliability. These technical refinements have revealed the potential for both a small open-cut operation and a substantial underground mining operation within the project area.

Coal Quality and Future Development Plans

Coal quality assessments confirm the presence of high-grade thermal coal with raw calorific values exceeding 6,000 Kcal/kg, and importantly, there is promising potential to upgrade portions of the resource to semi-soft metallurgical coal. This upgrade could significantly enhance the economic value of the project by tapping into higher-value coal markets. Yari’s Managing Director, Anthony Italiano, emphasised the importance of this resource growth and outlined plans for an inaugural drilling campaign in the second half of 2025. This campaign aims to improve resource classification from Inferred to Indicated or Measured and to confirm the coal’s metallurgical properties through test work.

Strategic Location and Infrastructure Access

The Rolleston South Coal Project benefits from its location in the Tier 1 Bowen Basin, a globally recognised coal-producing region. The project is situated approximately 40 kilometres from Aurizon’s Blackwater Rail System and less than 300 kilometres from the Port of Gladstone, providing excellent access to established rail and port infrastructure. This proximity to key logistics hubs is a critical advantage for future development and export potential.

Environmental and Regulatory Considerations

While the resource upgrade is a positive milestone, Yari acknowledges the need for ongoing environmental assessments and regulatory approvals as the project advances. The company has committed to meeting all environmental standards set by Queensland and Australian authorities, with further detailed studies planned as part of the scoping and development phases.