miner n.

c. 1300, minen, "to dig a tunnel under fortifications to overthrow them," from mine (n.1) or from Old French miner "to dig, mine; exterminate," from the French noun. From mid-14c. as "to dig in the earth" (in order to obtain minerals, treasure, etc.). Figurative meaning "ruin or destroy by slow or secret methods" is from mid-14c. Transitive sense of "to extract by mining" is from late 14c. For the sense of "to lay (explosive) mines," see mine (v.2). Related: Mined; mining.

1630s, from coal (n.) + miner.