I just re-read SUWA's materials and also browsed through the actual mining plan modification documents, thinking maybe I've missed something. But nope! SUWA is trying to "protect" a tiny portion of the lands shown in my Google Earth screenshots above. These are already heavily-disturbed areas.
This map is especially telling. It shows the proposed limit of new disturbed areas and the location of proposed new access roads that will be reclaimed afterward. It really does seem like a joke that they're trying to prevent disturbance on an already-disturbed area. Here is one of the roads SUWA is fighting against (I drew this based on the map linked above):
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The surrounding areas, yes, but not the already-ravaged areas into which they are proposing to expand. I don't see how the change in the mining plan will further affect any of the surrounding areas.
Maybe one could argue this would put more trucks on the public roads in surrounding areas, but that's a point that neither SUWA nor the mining plan modification addresses.