I think there are two mines. A substantial one in the NE that the entrance is surrounded by Poobah's workers village. Looks like a model workers camp the NW might be proud of until you look deeper. The miners are under paid, their is a comany store where they can buy marked up items on credit (my grandfather was a coal miner in the 20s and 30s). The second mine is Telgar's father's and is protected by the Dark and Expensive forest but is much more modest.
The NE mine is a mine of Solomon's proportion. Near slave labor. Producing $100k of profit a day.
Many guards, no real concern for miner safety. Many opps for thievery in both mines btw. Not sure what TG does with his mine if anything.