Yeah you can load any object you want, just have it load a non-enabled mine (the kind you can pick-up as loot).
Another option is to place activators for the minefield, and the activators place the mines. It's very easy to use OnReset on an activator to do something at a cell reset (and thereby avoid codeblocks running on lots of objects), and here that could be placing a mine if one isn't already placed. This way only destroyed mines need get replaced as well (you use 'set ref to placeatme mine' to allocate a reference that can be checked, disabled, enabled etc from the actvator.).
If you want to get a bit trickier, the entire minefield can be placed from a single activator -- you just use randomised X and Y placement values when placing the mines, and store a reference for each mine on the activator's script which you can play with (again to check, enable, disable, markfordelete etc)