The thing is huge. There doesn't seem to be another comparable crater on earth...How did it form? http://siberiantimes.com/science/casestudy/features/a-volcano-or-a-ufo-what-created-this-mysterious-siberian-crater/
Maybe a really big gopher made it. Chernobyl radiation caused it to grow to an enormous size. Where's Carl when you need him? http://www.youtube.com/watch?v=R5yCwN7wymc&feature=player_detailpage#t=66s
I saw something similar near Fulda during a regimental volksmarch. It was actually material dug out from a salt mine, piled much like this picture.
Im thinking mining tailings of some description...the centre dome suggests and impact, but the surrounds do not...