Even though the use of unmanned aerial vehicles (UAV) has been widely spread over the area of remote sensing, there are still uncertainties regarding the impact of parameters such as the number of ground control points (GCP), the image overlap or the ground sampling distance (GSD). In this study, we evaluate the accuracy of volumetric surveys performed with UAV imagery in open pit mines, assessing the influence of the number of GCPs on area and volume estimation. Our results suggest a density of 15 GCP/km² when performing precise volume measurements. In cases where only volume values are required and errors are acceptable below 10%, no GCPs are needed.