not much of an expert in mine warfare. From what I’ve read, a floating contact mine would not create the kind of explosion that would cause the ship’s keel to break in two. From a poster (who seemed to know what he was talking about) over at the Stategy Page forums said based on the facts known it could have been a mine anchored to the ocean floor or a torpedo - but what I find more interesting is that the NORK angle is now back in the pitcure
I don’t know jack about any kind of mines myself, but it seems “quite unlikely” that a Korean war-vintage mine sank a ship here in 2010...
Possibly combat swimmers.