No, I don't think that the MOA provisions are important in terms of limiting the legal recourse.

Environmental issues don't have any impact on the outcome at all -- it was known up front what mining does, and the provisions of the treaty make clear that things can be taken for public purposes (like saving the environment) BUT that fair compensation must be paid.

The interesting question would be what is fair compensation. Under American law, which I am much more familiar with, that would be the value of the contract at the time of the breach plus incidental and consequential expenses. IMO that is the net present value of all expected net income for the life of the project.

I don't want to dwell on this now, as I agree that this is a small probability outcome, and that politics will solve the problem.