Analysis of Large-scale Displacement Using Radar Interferometry Technology in Open-pit Mines (Case Study: Gol Gohar Sirjan Mine)

Mines with their displacements cause damage to infrastructure and land, so it is important to control the displacement caused by mines. Also, the amount of minerals extracted from mines has always been of interest to managers. On the other hand, radar interferometry, given the production of repetitive and full images and the acceptable accuracy of this method, in examining be suggested for the study of displacements caused by open-pit mines against methods such as Leveling and Global Positioning System that are generally expensive and timeconsuming. The surveyor engineers are responsible for calculating the displacement and volume of excavation in open-pit mines using the Leveling and Global Positioning System. The purpose of this study was to calculate the displacement caused by excavation in open-pit mines and calculating the volume of excavation. Because of the large-scale displacement in open-pit mines, the maximum displacement that can be extracted by radar interferometry technology is controlled by two factors: a) the wavelength of the radar images and b) the dimensions of the radar images, by increasing the wavelength of the images or reducing the pixel dimensions of the radar images, the maximum displacement gradient generated by the interferometric radar can be achieved.
On the other hand, rapid exploitation in open-pit mines creates decorrelation between the SAR images; To eliminate decorrelation images, selecting images with small spatial and time baselines can solve this problem. In this study, the Gol Gohar mine in Sirjan was studied using Envisat satellite radar images. Radar image processing was also performed using StaMPS software. In this study, the displacement rate is increased by changing the amount of multi looking factor images from 20 for azimuth and 4 for range to 5 for azimuth and 1 for range (reducing image pixel dimensions). After reducing the pixel dimensions of the image the maximum displacement obtained for a point in the mine changed from -51 mm to -75 mm, and also extracted volume changed from 61,000 cubic meters to 67,000 cubic meters after. So, by reducing the pixel dimensions of the radar images, the amount of displacement gradient is more detectable, and the value volume of excavation from mine will be more realistic.