Use of mining waste in agriculture. An example using emerald mining waste from Minas Gerais, Brazil.
Résumé
After adequate treatment, a lot of waste materials can be used to fertilize the poor lateritic soils of the Bazilian central part. The emerald-bearing schist found near Nova Era in Minas Gerais, Bahia and Goias States is tested here. It is rich in Mg, Ca, K, Zn and other elements important for plants, which lack in poor laterite tropical soils. Different quantities of schist were added to the soil and the evolution of soil chemistry and plant raising was observed for corn. The laboratory and field investigations show the good chemical overall evolution of the soil. Investigations by microprobe of the schist minerals indicated the longtime liberation of interesting elements from minewaste to soil fluids and the retainment of undesired compounds. The tests show that the use of waste material alone or in blending is a good and cheap possibility to lower mining impact and to get higher and cheaper food production.