My idea for minesweepers is as follows:
Mines, upon creation, are given a buff. This buff does nothing, but it's got an obvious name... something like "BUFF_HEYLOOKIAMAMINE". Mines are also made immune to damage.
Minesweepers have a kill mine ability, whose buff has two finish conditions: target does not have the "BUFF_HEYLOOKIAMAMINE" buff, or all delayed actions done. After a set period of time (half a second?), the buff will MakeDead the target mine (I haven't actually used that action yet in my modding, but I assume it does what it advertises.) This way, if you use the kill mine ability on something that isn't a mine, the buff should go away before the MakeDead is triggered (I hope), and if you use it on a mine, the mine should be destroyed.
This is all just theory at the moment, I haven't gotten far enough to implement the ability and try it all out.
Oh, and I was only thinking about proximity mines... hadn't even thought about remotely detonated ones... hmm, that's an interesting idea...