[jws]

As we reduce our coal use, the United States has a lot of absolutely enormous strip mining equipment going surplus. An obsolete 1960's era shovel moves 80m^3 in a scoop and that scoop is WW-1 era bomb proof for all practical purposes, say you want to dig down 4 meters, thats 20m^2 cleared per scoop. About 2 million scoops to clear a square mile. That one shovel should be able to pick up and sift a square mile of Europe in about 2 years. Granted, some of it will need to be run through an incinerator as well and you'd have the same environmental result as a used strip mine, but you can farm that and a square mile of France or Belgium should have resale value.

Edit: The German bucketwheel excavators like the Bagger 293 might do it faster.