Slopes are formed to carry out mining activities such as stripping, ore production, transportation, and waste management in open-pit mines. The instability of slopes is a potential source of risks for mine safety. An unexpected slope failure may damage people, buildings, and equipment in the immediate area. Moreover, it leads to the disruption of mining production and an increase in production cost. For this reason, the regular examination and systematic monitoring of slopes should be performed to determine the early warning signs of failure. Thus, it may be possible to reach acceptable risk levels and to plan and implement the necessary safety measures. In this study, deformations at a common dump site of three different open-pit marble mines located in Eliktekke region of Amasya province (Turkey) were investigated by the permanent scatterer interferometry (PSI) technique using satellite radar images. The results obtained from the PSI technique were compared with global navigation satellite system (GNSS) and unmanned aerial vehicle (UAV) photogrammetry results which had been conducted by Hastaoglu et al. (2019) in the same study area. Velocities in the satellite line of sight (LOS) direction approaching -70 mm/month were determined from the PSI results of this dump site. Although the obtained results provided the overall coherence at this site, different results were found from GNSS and UAV photogrammetry in the areas where step geometry (height, width, inclination) changed along with the ongoing dumps and frequently changing surface topography due to dumping. While deformations occurring in slow motion and in a long time could be revealed by the PSI technique, displacements that occurred instantly and in a short time could not be determined. This study showed the detectability of surface deformations in open-pit mines by the PSI technique and problems that might be encountered during the analysis stage.