In this research work, the bio-leaching of Co and Ni from an iron-rich laterite ore is assessed using the acidophilic heterotrophic (Delftia acidovorans)and autotrophic (Acidithiobacillus ferrooxidans) bacteria. The metabolic products of the acidophilic bacteria play an important role in bio-leaching. The results obtained from the indirect bio-leaching indicate the highest nickel recoveries of up to 83.65% and 80.18%, respectively, by the supernatants of Acidithiobacillus ferrooxidans and Delftia acidovorans, both measured at 90 °C for 3 h with a stirring speed of 370 rpm and S/L of 0.1, while the corresponding cobalt recovery rates have reached 86.93% and 83.94%, respectively. The iron dissolution rates in these conditions for the two studied bacteria are 64.34% and 54.41%, respectively. The nickel and cobalt extractions by the indirect bio-leaching of Delftia acidovorans are, respectively, 29.84% and 23.75% higher than those for the direct bio-leaching, performed at 30 °C and 150 rpm of an incubator shaker for 30 days. For the indirect bio-leaching, the chemical control has a larger influence on the dissolution rate of the iron-rich laterite compared to the diffusion control. The activation energies of nickel and cobalt in the chemical control model are 40.07 and 39.08 kJ/mol, respectively.

In this research, ASTER satellite images and the combined algorithm of band ratios with the method of logical operators with the determination of the threshold limit based on ground, laboratory and experimental studies have been used in order to highlight hydrothermal alterations. Image transformation techniques such as specialized band ratio and principal component analysis are used to map lithologic units and alteration minerals. Supervised classification technique, i.e. Spectral Angle Mapper (SAM) is applied to detect subtle differences between index alteration minerals associated with actual copper localities in the region. The results show that the integration of image transformation techniques and supervised classification of ASTER data with field studies and geochemical exploration is highly effective in targeting new copper mineralization prospects. Copper mineralization is found in siliceous veins that strike from north-south to northeast-southwest across the region. Remote sensing evidence supports the presence of propylitic and argillic alteration, which can be useful for searching for copper-gold type deposits. Kaolinite and pyrophyllite play a role in identifying arzilic alteration zones, and muscoite, epidote and chlorite minerals are very important in identifying pyropilitic and phyllic areas and in mineral exploration. Based on remote sensing processing, according to the detection of various alterations (phyllic, pyrophyllite and argillic) in this area, possible copper mineralization was detected in the central part of the studied area. The approach used in this research provides a quick and cost-effective means of initiating comprehensive geological and geochemical exploration programs in the study area and elsewhere in similar areas.