Eddy Potash Mine, New Mexico

The Eddy Potash mine and plant has been abandoned and closed for some time. Under the plant, around 1,000 feet down, are several square miles of mined room and pillar space. This mine is connected to three other underground mines that collectively cover nearly 50 square miles of excavated room and pillar space. The Eddy Mine was bought by Intrepid Potash in 2004, and these empty spaces are now part of their HB Solution Mine operation. The solution mine flushes water through the rooms in portions of these interconnected mines, creating underground leach lakes that dissolve pillars that were left to hold up the ceiling, but which are no longer needed. The solution is then pumped into evaporations ponds nearby.