This is my jam. Mines are super complex problems. These guys are dealing with abandoned/legacy sites which is even more challenging, since soil for reclamation is usually non-existent. The older the mine, usually the worse it is in terms of contaminants.
I wrote a paper on a mine up north that had Arsenic levels of 9,200 ppm. For reference, soil quality guides for limiting impacts to humans and the environment is 50 ppm…
So yeah, a bit of an issue.
One of the things I like that they are doing is they are using a pretty broad reveg prescription (multiple spp). This will help kick start things.