Most mining operations generate tailings when separating the valuable minerals from the excavated ore body.  Historically, those tailings were discharged into ponds, impoundments, mine dumps, clum dumps, slime tailings, leach residue, tailings dams, or slickens.  Here the tailings tend to leach water that will carry heavy metals or other contaminants.

Coal–fired power plants currently fuel 37% of global electricity and create a number of waste streams including, overflow from floatation tanks to separate fine coal and the separation of unburned carbon from the bottom ash. Treatment solutions include dewatering of the tailings with belt presses and using paste thickener technology (addition of cement) and processing of underflow tailings as part of the floatation process.