Owner of a large quantity of salt, reaching a higher level of saltiness than someone who is just merely "salty."
Observer1: Yo, that kid just got straight up owned for free.
Observer2: Yea man, he's mad salty.
Observer1: Salt mines owner for sure.
The last place on earth you'd want to be.
Boss: Ok see you in the office tomorrow morning.
Employee: Ok see you in the Salt Mines