My — used before a word beginning with a vowel or h or sometimes as a modifier of a preceding noun — archaic except in an elevated style

1. A pit or excavation in the earth from which mineral substances are taken; an ore deposit
2. A excavation in the earth from which ores and minerals are extracted.
3. A rich source of supply

A device that explodes on contact; designed to destroy vehicles or ships or kill personnel.
An encased explosive that is placed in the ground or in water and set to explode when disturbed

That which belongs to me — used without a following noun as a pronoun equivalent in meaning to the adjective my

ETYM French miner, Latin minare to drive animals, in Late Lat. also, to lead, conduct, dig a mine (cf. Eng. lode, and lead to conduct), akin to Latin minari to threaten.
1. To get from the earth; of ores and metals.
2. To lay mines.