BHP says it can double copper production in Australia without increasing the volume of uranium that comes from the same mines, hosing down investor fears that a multibillion-dollar expansion of Olympic Dam would create a flood of unwanted supply.

BHP made that disclosure in the paperwork submitted to authorities as part of the proposal to expand the smelter at the South Australian mine, a revelation described as “phenomenal” news by uranium investors who had expected the project to boost supply and lower prices for the nuclear fuel.