Reclamation of bentonite mined lands in the northern great plains

Ninety percent of the nation's supply of bentonite is mined in Montana, South Dakota and Wyoming. These lands are difficult to reclaim because of the chemical and physical properties of the soil/spoil material and the arid/semiarid climate of the area. Replacement of the limited topsoil available has shown some benefit but supplies are generally inadequate. The use of inorganic amendments, such as sulfuric acid, gypsum, calcium chloride, vermiculite and perlite, have not shown consistent benefits in plant establishment and growth. Organic amendments; sawmill wood residues, straw and manure, have provided the greatest benefits in the reclamation of bentonite mined lands. Cultural and management practices are important in determining the long-term success of these reclaimed lands. Reclamation technology development for bentonite mined lands is recent and limited and the refinement and application of such technology will depend on increased activity and cooperation among researchers, regulators and the mining industry.