This may have already been suggested, or perhaps something similar. But either way, here goes.
Take a "minesweeper" unit - let's call it the scout for argument's sake. It has an automatic minesweeping mode which you right click to activate. In this mode it will automatically go around detecting and sweeping mines. Perhaps it can even be coupled with the other button which tells it to operate either in the local area, or the entire gravity well.
But here's the kicker - THE MINESWEEPING ABILITY TAKES ANTIMATTER OR MANNA OR WHATEVER IT'S CALLED TO USE. Why? Two reasons at least:
1) The person who laid the mines had to spend mana to do it. You should spend mana to undo it.
2) The person who laid the mines had to spend time to do it. You should spend time to undo it. This time will be in the form of the minesweeper having to recharge its ability every so often. A starting balance would be for the minesweeper to use the same amount of time sweeping as the layer used to lay. Another balance would make the minesweeper take longer, DUE TO THE FACT THAT THE LAYER WAS MICRO'D TO LAY THE MINES.
It's just an idea, but an idea like this not only keeps mines, along with their effectiveness, but it eliminates micro and tedium as well. A win/win?