Notice [SOLD] Untouched dungeon I found on SMP4, leads into an abandoned mineshaft. Found in unexplored land quite a ways from the main spawn. If you are looking to create an XP farm far away from spawn from an untouched zombie dungeon, this is for you. Price for Coordinates: 2000r Guide to selling mob spawner locations below: http://empireminecraft.com/threads/guide-selling-mob-spawner-locations.9738/
I made a map displaying the area where the dungeon is located so you will have no trouble finding it, but it is quite a ways away from the spawn so you won't have to worry about people snooping around your XP farm.
Haha that was pretty funny, I know the dungeon is pretty far from spawn but its definitly worth the investment. I have an XP farm of my own and their great.