splitting up mine types makes placement logistically complex for them to ever be used in the way you're intending. mine counts should be increased to something like 16 with a minor damage reduction. considering that mines have done about the same damage to infantry, historically (death), they are not that hard to balance. it's a matter of pacing, since mines in early game are devastating along with other gren weapons, where in later game, especially with defusal, they are largely useless.