The strange shape of the Roman province of Dacia [1], which was vulnerable on three sides (West, North and East), was most probably the result of the Romans' desire to posses this salt-mine and some other ones located near-by. Turda used to be called Potaissa [2] back in those days (you can see it in the center of the map that I linked to), and there was almost always a Roman legion stationed there.
There were also some actual gold mines that the same Romans were taking advantage of close-by, at Alburnus Maior (also visible on the map).
[1] https://en.wikipedia.org/wiki/Roman_Dacia#/media/File:Roman_...