Rehabilitation of Mined Bauxite Lands At Pocos De Caldas, Minas Gerais State, Brazil
Journal American Society of Mining and Reclamation
Since 1979, Alcoa Aluminio s/ A has rehabilitated 85 hectares of mined bauxite lands on its mineral concessions on the Poc;os de Caldas Plateau in Minas Gerais State, Brazil, 180 km north of the City of Sao Paulo. The Plateau is an alcaUne ring structure, 30 km in diameter with elevations of 1200 to 1600 meters. Bauxite occurs on steep mountain ridges and flanks and on lower rolling hills, in orebodies that range from several thousand up to, uncommonly, one million tonnes. Ore thickness is
... ic, but averages 4. 5 meters, and is covered by a soil layer 20 to 80 centimeters thick with natural grasses or sub-tropical rain forest. Presently 10 hectares are mined annually. Rehab!l!tation consists of pre-mining soil stripping and storage, post-mining terracing, drainage works, topsoil replacement, grass and legume hydroseeding, and tree planting with native species. The common size of a rehabll!tation unit is 100 by 300 meters. Vegetation growth is fast, plus native vegetation quickly invades the areas. The average cost of rehabll!tation has been 6. 5 cents per crude tonne of bauxite mined, or $4,075 per hectare, or 18 cents per tonne of aluminum oxide produced in Alcoa's local plant.