Farming
-A way to "farm" them is to make a large tunnel, covering possible spawn areas, and 2 holes 9 blocks wide and 9 blocks deep around you. They will collect in the holes and can be attacked with ranged weapons.
-A somewhat good farm for the Undead Miner.
Another way to farm them and other items, is to make a large tunnel located at stone layer, covering possible any spawn areas, using dungeon brick creating a 25*25 box. Place the farm in the middle of the large tunnel, this way mobs will come from both sides. Note the lava pits around the bottom left and right corners of the mob to neutralize them, while the top takes care of the bats. This farm allows retrieval of both armor drops as well as a nifty amount of coins, gels from mother and baby slimes, hooks, bombs, as well as the whoopie cushion. For the whoopie, a simple pillar with the explosives item, and a switch properly aligned. The middle will attract the worm to climb up in which the player sets off the explosives.
Tiré tout droit du wiki pas officiel : http://terraria.wikia.com/wiki/Undead_Miner
Si ça peut t'aider