Train gamer, Euro gamer and War gamer
Typically, Mines are only destroyed by Artillery strikes (if you destroy fortifications in a hex- rare), or by the use of an action card like Sappers.
mines can be removed with sapper event too .....
I'm not seeing Sappers as an action nor as an event in the Pacific rulebook. There is a Sappers Event in Europe (E70).
I'm looking through the Pacific rulebook, and I only find two events that could remove mines: Blaze and Breezy. There are two Actions that could remove them: Demolitions and Explosive Charge. Although I would not play Explosive Charge to remove a mine marker in the opponent's hex.
And as Patrick (Farsol) mentioned, possibly by artillery (or dive bomber) strikes.
Fortifications can be eliminated during play
via various events, the Demolitions action
[A38], the Explosive Charge action [A40] or
the Fortification Vulnerability Table [O24.3.4]
when its hex is attacked by artillery or dive