Definitions:
used to refer to a thing or things belonging to or associated with the speaker

(used before a vowel) my

an excavation in the earth for extracting coal or other minerals

a type of bomb placed on or just below the surface of the ground or in the water, which detonates on contact with a person, vehicle, or ship

obtain (coal or other minerals) from a mine

lay explosive mines on or just below the surface of (the ground or water)