Yes really, IF one assumes as they obviously do that the treaty land was and is 100% theirs. That means land surface, all on it, below it and probably above it.

And I personnally would agree if that treaty was between to European entities that had deeds, and assets were priced per European means. Yes even if using times past of a hundred or more years. However I do not agree that they owned the land nor the extent specified in treaty as per commonly understood norms of the time.

There was no response from the Ontario government because it was mostly considered not worth responding to. Or perhaps the opinion was - Take me to court and prove it.

Seems to me that it was a starting point to provoke negotiations and one usually starts with the maximum that one could possibly imagine. Remainder is subject to debates, discussions and finally compromise.
As with out present Noront concerns, those negotiations could go on into the next century.