Grange Resources (ASX:GRR) said mineral resources and ore reserves at its Savage River operation in Tasmania as of end-2025 remain at similar levels to the previous year, according to a Thursday filing with the Australian bourse.

Mineral resources decreased by 3.6 million tonnes, or 0.8%, over the 12 months through December solely due to mining depletion. Meanwhile, ore reserves have fallen by 3.8 million tonnes, or 3.8%, on account of mining depletion, refinement to mine designs, and an updated production schedule, the company said.

Underground project activity at the operation included 64 meters of lateral development, 260 meters of vertical development, and the completion of a ventilation system for the next phase of decline extension.

The underground ore reserve is now supported by 5,100 meters of lateral development, 430 meters of vertical development, nearly 37 kilometers of drilling with 55 holes defining the underground mineral resource, and a 20,000-tonne bulk ore sample drive, per the filing.

Shares of Grange Resources were down 2% in recent trading.