Critical minerals from mine wasteHere's a SME paper discussing mine waste CM opportunities - seems like there's much enterprise potential with this historically overlooked source and the US government is interested in helping exploit this. Interestingly, its fig 1 diagram indicates that host copper deposits contain more cobalt than bismuth. RIO has likely already characterized the concentrations and hence now are proceeding with FT process testing. I would imagine that potentially not only could their waste from current operations be a significant source of cobalt and bismuth, but also legacy waste. As well, RIOs Kennecott smelter appears to have historically processed not only ore from their Bingham Canyon mine, but from other US copper mines, so maybe other copper ore bodies waste could also be potential feedstock for FT down the road - likely many possibilities for additional domestic bismuth and cobalt sourcing exist.
https://www.smenet.org/What-We-Do/Technical-Briefings/Critical-Minerals-Produced-from-Alternative-Resour