manganes

Revista Brasileira de Geof´ısica (2007) 25(2): 199-212
© 2007 Sociedade Brasileira de Geof´ısica
ISSN 0102-261X www.scielo.br/rbg ´
ANALISE
DE DADOS HIPERESPECTRAIS EM MINA DE MANGAN Eˆ S LATER´ITICO,
˜ JOAO
˜ DA ALIANC¸A (GO)
SAO
´ de Souza Martins3 ,
Osmar Ab´ılio de Carvalho J´unior1 , M´ucio Nobre da Costa Ribeiro2 , Eder
Edi Mendes Guimar˜aes4 , Paulo Roberto Meneses5 e Renato Fontes Guimar˜aes1
Recebido em 30 abril, 2007 / Aceito em 28 junho, 2007
Received on April 30, 2007 / Accepted on June 28, 2007

ABSTRACT. The aim this paper is to develop a methodology of lateritic manganese identification using imaging spectroscopy. In this study was used the Airborne
Visible/InfraRed Imaging Spectrometer (AVIRIS) image. The AVIRIS is an imaging sensor that measures the solar reflected spectrum from 400 nm to 2500 nm at 10 nm intervals. The study area is located at Goi´as State and enclosed the Fazenda Extrema mine that presents lateritic manganese deposits developed on Parano´a Group rocks. Laboratory spectrometry studies conjugated with mineralogical analysis by diffractometry of X-ray demonstrated that the ore spectrum is opaque and spectrally featureless, due to the conduction band of MnO3 extending throughout this spectral range. The digital image processing can be subdivided in the following steps: (a) atmospheric correction using Green method, (b) areas selection with opaque behavior from the integral spectra calculation, and (c) lateritic manganese individualization using the Minimum Noise Fraction transformation. The method is efficient to classify areas of abandoned manganese mine that consist of priority areas for implementation of environmental recovery.
Keywords: spectral mixture, hyperspectral; imaging spectroscopy, manganese, laterite.

RESUMO. O objetivo do presente trabalho foi desenvolver uma metodologia para identificac¸ a˜o de lateritas manganes´ıferas por espectroscopia de imageamento. Nesse estudo foi utilizada a