Application of UAV photogrammetry products for the exploration of dimension stone deposits: a case study of the Majestic Rose quarry, Kerman province, Iran

This research aims to show the capability of unmanned aerial vehicles (UAVs) for aerial fracturing survey, determining the block size, and estimating the reserve of dimension stone deposits. The Majestic Rose marble quarry in Kerman province, Iran, was selected as the case study. The quarry presents large outcrops and rugged topography. UAV-based imagery was applied as a time- and cost-effective solution for acquiring highly accurate geological and structural data across the deposit. An aerial survey was conducted at 70 m altitude with 70% lateral and 80% front image overlaps. About 47 ground control points (GCPs) were used to increase the surveying accuracy. The orthophoto image with a spatial resolution of 2.97 cm/pix was applied to specify geological units and the deposit boundary. Due to the importance of fractures in the exploitability of dimension stones, the orthophoto image and hill-shade model were used for enhancing the fractures. A fracture density map was created to delineate critical zones. The fracture spacing was determined to estimate the average block size in critical zones. A digital elevation model (DEM) with an accuracy of 2.28 cm was used to reconstruct the 3D deposit model. An accurate block model was created using the 3D deposit model for estimating the resources in the eastern and western sub-zones. This research showed the capability of UAVs in increasing the efficiency of mineral exploration programs of dimension stones. The proposed methodology can be customized for other surficial deposits considering the mineralization type and geological setting.