A miner is a person who works in the field of natural resource extraction. This profession is called mining.
Among the lithium miners on planet Rigel XII in 2266 were Ben Childress, Herm Gossett, and Benton. (TOS: "Mudd's Women")
Over fifty miners working at the mine on the Janus VI colony were killed by a Horta in 2267. (TOS: "The Devil in the Dark")
Harry Mudd attempted to exploit the heavy metal miners on Motherlode in 2269 by selling them an illegal love potion. (TAS: "Mudd's Passion")
While on Ophuicus VI, Mudd conned two miners out of a year's supply of dilithium crystals using fake Federation vouchers. (TAS: "Mudd's Passion")
Some EMH mark 1 holograms were reconfigured as miners of dilithium after becoming obsolete in their original programming. (VOY: "Life Line", "Author, Author")