Bill D is correct; experimentally methods such as burning in situ, heating by various other methods using horizontal driling, etc., have not worked practically. The monster holes being dug in the formerly boreal forest of northeastern Alberta, and the clearing of land surrounding them, look like something seen on barren planets. Partial filling, and lakes are planned, but the concentrated contaminants, I am afraid, will leave scars for at least a century regardless of reclamation efforts.

In Illinois, I have seen where the overburden has been restored and planted after strip-mining of coal layers, but the ecology of the area is changed. Although covered by four feet of soil slurry by regulation, acid leaks from the former coal bed site. The reclaimed areas are turned into wetlands or grasslands but the land, which was prime agricultural land before stripping, will not return completely to that state, although massive amounts of limestone (50-75 tons/acre) are tilled into the soil and covers like winter wheat are planted. Acidity can leach upward years later, so the problem is not completely solved.
This article, "From Wastelands to Wetlands," Southern Illinois University, is too optimistically cast, in my opinion, but is shows what is being done. Written eight years ago, I know of no advances in the field since then.
Wasstelands to Wetlands