Have an entire crew looking and pointing, saying..."MINE!"
I don't see a need to spot mines. Because when you are fighting against mines,
1.) The enemy makes a minefield that you can (and should) easily notice and avoid.
2.) The enemy has a proficient gunner who can pop a mine on you (and you can't do much about it).
So, yea, its part of piloting progress to learn how to avoid mines. Kinda like learning chem-cycles as engineer and reload-timing as a gunner.