Application of aerial photogrammetric technology for determination and parametrization of areas affected by extraction of raw materials

Extraction of mineral raw materials is increasing due to economic development and must be a normal process under due control and environmental supervision. However, there are a number of sites where the exploitation was stopped and mining sites were abandoned without proper restoration. Also, there are sites where mineral resources were or are extracted illegally thus making significant damage to the environment and economy. In order to collect information on land impacted by mining and extraction activities, for the first time a special project was carried out for the entire territory of Lithuania. The project consisted of gathering of information on damaged areas from various sources, field surveys and systematization of collected data. In order to obtain volumetric data, a special technology of aerial photogrammetry was developed and successfully applied. It was detected that the number of damaged sites > 0.3 ha reached up to 3,300. It is estimated that a total amount of illegally extracted minerals in last 15–20 years could be up to 15 million m3. The aerial photogrammetry was proved as a relevant technology and this could be applied for the control of the restoration of damaged land as well as for the monitoring of hazardous geological processes, e.g. coastal erosion, karst.