SIBANYE-Stillwater’s gold mineral reserves fell 6.3% to 9.4 million ounces at end-December owing to a significant writedown at its Kloof mine in Johannesburg.
The Johannesburg-listed miner said production constraints at Kloof, including geotechnical considerations that forced the removal of isolated blocks of ground, had impaired the economic viability of the operation, resulting in a 1.4 million oz reduction in mineral reserves.
The writedown came despite Sibanye-Stillwater raising its gold reserve price assumption to $2,650 per ounce for 2025 from $2,421/oz in 2024, a move that would ordinarily support reserve additions rather than cuts.
Across the broader South African gold portfolio, which includes DRDGOLD and development projects such as Burnstone in Mpumalanga province, mineral resources dropped sharply, falling 25.5% to 36.4 million oz.
The group’s PGM operations provided a partial offset. South African 4E PGM mineral reserves rose 4.7% to 29.4 million oz, with the Marikana E4 mechanised UG2 project contributing a 2.9 million oz addition following completion of a feasibility study.
Sibanye-Stillwater lifted its platinum reserve price assumption to $1,350/oz from $1,250/oz in 2024, while the palladium assumption rose to $1,350/oz from $1,150/oz. US PGM mineral reserves edged 2.1% higher to 19.4 million oz.
Sibanye-Stillwater also declared a maiden uranium mineral reserve of 25.2 million pounds of uranium oxide at its South African gold operations, underpinned by a completed feasibility study at the Cooke tailings storage facility. The uranium reserve price assumption was set at $100 per pound, up from $90/lb in 2024.
At the Century zinc operation in Australia, reserves fell 44.2% to 308,000 tons, with the tailings mineral reserve carrying approximately 18 months of remaining life.
