Full comment from the Anto earnings call below. They are pretty sportmanslike, but of course that's more easy if TMM is just a sideshow (backstage?)...
"At Twin Metals, we have terminated our option to acquire an additional 25% interest in the project and operational control has been transferred to Duluth Metals. The project is still of interest to us, as it is a good deposit, but the disproportionate funding will require to provide to the end of the feasibility study adversely impact our returns. Now that the pre-feasibility study has been completed, we are waiting to see how Duluth plan to proceed with the project.
However, as we have terminated our option, Duluth have the option to acquire our 40% interest for our sunk cost of approximately $220 million plus the repayment of $10 million loan. They have until January next year to decide on this. Otherwise the project can proceed on a conventional pro rata joint venture basis."
https://seekingalpha.com/article/2451705-antofagastas-anfgf-ceo-diego-hernandez-on-h1-2014-results-earnings-call-transcript?part=single