Surface mine spoils make really bad soil. The only things that can grow on mine spoils are agressive grasses and invasive shrubs that keep anything else from growing and freeze the ecosystem, keeping from developing naturally into a forest. They're basically an extremely rough and compacted gravel, with bits of clay, dirt, sand, and the occasional enormous boulder. They are also not laid down in any particularly useful pattern, which means that things like nutrients and soil pH are really high or really low depending on where you are.
The Conservancy used a really badass machine called a "Masticator" to chop down and mulch all the invasive plants in one step. To try to fix the compaction problems, they went in with what's called a "Deep Tiller" or "Deep Ripper" and opened up the soil enough to allow tree roots to get a foothold. They then fertilized and limed the whole site, trying to even out the differences in nutrition and acidity.
After all that, they planted a few hundred native trees that are good for timber, and a smaller amount of "wildlife" trees. The trees are surviving, but they aren't growing as much as they normally would, because of the soil and because the invasive grasses grew back and are shading them out. The Nature Conservancy threw around the idea of herbiciding the grasses from the air (before planting trees), but decided that it would be too dangerous to the ecosystems downstream. Fire is out of the question too, since the area still has coal seams and natural gas deposits that might explode, or maybe just burn for a few hundred years. So now they're stuck spot spraying herbicides around individual trees, which you can imagine is a time consuming process.
So what's my involvement? I'm gonna help these folks by GPSing the sites. Preety easy work, just walk around the perimeter of the planted land and push a button every once in a while. Wish me luck!
Brad and Teresa from the Nature Conservancy on the site, overlooking the some of the land they're trying to save.
* If you want the full scoop on this project, check out TNC's report here: http://aozeba.googlepages.com/TNC_ABC_Reforestation_FinalReport.pdf