The two mines near Rellekka are both not as useful as one would hope. They are both fairly far from banks, though the gold/silver mines close to here are useful once you have finished The Fremennik Trials quest. They are reasonably useful though you would have to drop everything you make, if you don't want to go to closest bank which is in Neitiznot. If you completed the Fremennik Diary, you can use Peer the Seer to bank items as well.