Good post. My Dad participated for quite a few years in research and trial projects restoring strip mined land where lots of nasties were distributed all over the place, including at varying depths, sometimes aquifers were ontaminated with said nasties, etc. Pretty interesting stuff, even if I was only catching “pieces” of info from him now and then.
One location (with some add-ons) is now a 20,000 acre state park with over 30 fishable (and most stocked) ponds and lakes on it.
That’s not exactly the same thing as this situation, but, it gives me a good sense of the correctness of your post. :-)
Re. strip mines, this was my first exposure to truly huge scale equipment. My very first assignment out of college though was to supervise a work crew working in an in-plant junk yard to modify an old tank to a new duty within a large pilot plant. “Supervised” a work crew that didn't speak English. Hotter ‘n hell summer on the Texas gulf coast. Got my fork lift stuck in the mud. The real purpose in throwing me into that hell was to drive the notion out of me that working in an idealized air conditioned office was formally out the window.
Second professional exposure touched on strip mining and was a few months later when I was assigned to tag along with a research chemist running a project at a power plant in the lignite fields located in NE Texas. Several of these power plants were active in the lignite fields. Basically, a power plant with a 20-30 year service life was plunked down in the middle of a lignite field. The field surrounding the plant was strip mined then when the lignite was exhausted, the power plant was decommissioned and demolished.
Terraforming to restore the land began soon after the active mining was sufficiently distant from an area. Top soil is a precious material and had been scalped off and securely protected. Other under soils were also piled. The soils were layered back in.
This land in native form had been fairly rugged cattle ranching lands. Little if any farming because of the climate. In the terraforming, the land was contoured into smooth hills much like nature created in the Dakotas wheat and cattle country. Water drainage for the seasonal drainage provided for. Native grasses planted and flourished. End result was happy cows and greatly improved land productivity.