Here are a few things regarding Mines.
BASICS
The initial conception of mines are to apply a maximum amount of force with the lowest possible yeild. The primary function of which is like most traps, to disable/destroy one or more foes with the most minimal of cost to you. As Frost said, Mines are a one time/shot deal. They are ment to be used once. Therfore, mine MUST have the most destructive force when used for the lowest cost.
Having a left-over/re-usable mine is not the point and therefore a waste of material. This would make a one shot gun type mine inefficient(sp) and against the purpose of a mine.
Area denial mines are larger mines with more technical usage
GAME IMPLIMENTATION
Most likely, the implimentation of mine in the game( if they are put in) will be as a typical large area field that would server to seal off a region of space and allow for a minimal defnse force to stay and watch over the field.
I kinda took a break in this response and totally lost my train of thought so you wont get a long post for this