Abstract

Remote sensing is used in this work as a geological reconnaissance technique, demonstrating that it is profitable and effective in providing valuable information for distant regions of mining interest. Due to the Civil War that affected Sierra Leone from 1991 to 2002, Sierra Leone's mining resurgence has focused only on restoring closed mines and the exploitation of previously proven reserves. Thus, the main objective of this work is to locate new iron ores in the districts of Marampa and Tonkolili, located in areas outside the mining licensee sites where previous exploratory studies have not been carried out. To do this, Landsat 5 TM multispectral satellite images were used. Two different spectral enhancement methodologies were applied: Colour composition with band ratios and principal component analysis (PCA) applied to band ratios. The results were integrated to generate a map that delimits areas with exposed mineralization of iron oxides, which allowed us to associate them with the regional geology. Finally, access roads are included for field checking and detailed exploration.

Key words: Remote sensing, iron ores, PCA, spectral signature, Landsat 5 TM.