Satellite data application in environmental monitoring of ilmenite open-cast mining (case study of Mezhyrichne deposit)

Abstract

The development process of titanium ore deposits is always accompanied by anthropogenic changes in natural landscapes, which, in turn, leads to several negative environmental impacts. Therefore, it is necessary to monitor mining areas. This paper presents the results of satellite monitoring of the Mezhyrichne deposit territory of the Irshansk placers group, which has been developed for over 20 years. The assessment of the ecological state includes assessment of forests condition, factors impacting the microclimate and the level of pollution by iron oxides and hydroxides. Spectral indices NDVI, NDWI and leaf area index (LAI) were used to assess the condition of forests. Among the factors impacting the microclimate, values of surface temperature distribution and evapotranspiration according to the Sebal model were calculated. As a result of the study, water loss in trees was detected within adjacent areas to the mining concessions due to the groundwater flow into cones of depression, formed under the influence of quarrying. The analysis of surface temperature distribution and evapotranspiration showed a simultaneous increase in the first one and a decrease in the second one, which is a signal of negative changes in microclimate. No significant contamination of the earth’s surface with iron oxides was detected. The maximum values of the iron oxide index (IOR) are associated with the mining concession objects especially the tailings. In general, the impact of open-pit mining of ilmenite on the environment is not critical, which is due to the use of mechanical methods of ore enrichment. The main changes of the environment take place within the mining concessions, which territory is subject to mandatory restoration after exploitation is stopped. Further research is planned to involve new modern multispectral satellite data and new methods of digital information processing in combination with ground truth measurements.