A mine finder is a worthless 'member' of society. Someone who doesn't contribute to the world and would be better served standing on a land mine so that innocent farmers and villages in places like Cambodia wouldn't. Their greatest contribution to the world would be in death, spread over a paddock.
John: Hey, did you see that dickhead druggie passed out on the train today.
Jimmy: Yeah, another mine finder in need of a one way ticket to Cambodia.