I agree it IS alarming... and yes reforestation can recover these areas, though there are no such things as rebuilding mountains.... once they are gone, they're gone. But if you look at the area around Angles Camp and Columbia, California.... that was all sluice or (placer) mined heavily during the 1800's gold rush and they absolutely tore the land to shreds. And now it looks beautiful... on the surface...but if you get off the trails and look around you see the remains everywhere. It is horrible. So yes, on the surface they can be rebuilt but not even 50% back to normal.
The point really it that it is patently unnecessary to do this sort of destructive mining. With modern technology, alternate energy resources, composite materials, alternate materials like hemp...and in the event mining is necessary for some particular uber needed resource....then modern mining techniques can be used which make a world of difference.
The problem is these things are expensive... whereas most of the time companies would rather get in, dig it out and leave. They only care about enriching a small number of people at the expense of the rest of us. Sad really.