The owner of two precious metals mines in south-central Montana is stopping work on an expansion project and laying off about 100 workers because the price of palladium fell sharply in the past year, mine representatives said Thursday. Sibanye-Stillwater announced the layoffs Wednesday at the only platinum and palladium mines in the United States, near Nye, Montana, and other Sibanye-owned facilities in Montana, including a recycling operation. Another 187 contract workers — about 67% of the mining contract workers at the mine — will also be affected.