Some practical problems of photogrammetry based volume control of open-pit mines

A 3D model based on aerial photos, created using the photogrammetric method, provides a new and quick opportunity to analyze the volume of open-pit mines. Modern fixed wing drones or multicopters are cheap alternatives to aerial photography done by man. Depending on the size of the mine, high-detail aerial photos can be taken within less than 60 minutes flight time, using drones. During the method, which is detailed and is also verified by practical tests, orthophotos, with a detail of 2-3 cm per pixel, and surface-detailed 3D models have been made, with a size of 1-3 cm. The volume data, which was calculated based on the models, was compared with control surveys of regular geometrical formations (artificial pools), having an already known volume and can be measured using conventional methods. Verifications have pointed out that the photogrammetric method produced results within the error margin of 1-2 %, by processing drone photos. Therefore, drone surveying can be considered an efficient, quick and reliable enough volume computing method. It must be mentioned that the method can produce a more accurate volume result compared with conventional geodetic surveying, because it takes certain changes in terrain into consideration, as the interpolation method of a limited number of measurement points.