Detecção da expansão da área minerada no Quadrilátero Ferrífero, Minas Gerais, no período de 1985 a 2011 através de técnicas de sensoriamento remoto

Abstract

This study aimed at analyzing the evolution of the mined area in the Quadrilátero Ferrífero (QF) region, Minas Gerais state, Brazil, as well as to quantify the area covered by native forest that has been removed by mining activities during the last 26 years. TM/Landsat5 images from 1985, 1989, 2000 and 2011 were used. For each year of analysis, polygons of mined areas were detected and delimited using visual image interpretation techniques. For the analysis of the area covered by native forest suppressed by mining activities, a land cover and land use map of the QF region was provided, by using images from 1985. Native forest areas suppressed by mining expansion were calculated overlaying the thematic map and the mining polygons for each year of analysis. Taking into account the period from 1985 to 2011 there was an increase of 213% in the mined area. The areas of native forest removed throughout the years 1985-1989, 1989-2000 and 2000-2011 were respectively equal to 324.42 ha, 948.98 ha and 1,989.68 ha, with a total loss of 3,263.07 ha.