Application of Unmanned Aerial Photography for the Estimation of Extracted Rocks – Beautiful Rock Quarry, Nigeria Experience

Abstract

This research was carried out to investigate the application of unmanned aerial photography for the estimation of extracted rocks at Beautiful Rock Quarry, Lokoja, Nigeria. To achieve the aim of the research, the aerial views of the 2D images captured were used to generate the aerial views in 3D models for the Digital Terrain Models (DTMs) and the Digital Surface Models (DSMs). Image Processing Software’s (ImageJ and Regard3D) were used for the processing of the images. Correction checks were made for the Sensor Coordinates due to tilted aerial photograph and the Ground Coordinates were established. The images of the Extracted Pit and the Stockpile were analyzed using the image processing software’s to identity elevation spots and generate Z – Plots for the Pit and the stockpile. With the results generated from the image processing software’s; the extracted rocks from the Pit is calculated to be  1,027,204.512tons while the total production of aggregates sold from the Quarry since 2012 to 2020 is documented to be 1,715,800tons. The difference between the tonnage of extracted rocks from the Pit and the total production of aggregates sold from the Quarry was due to Swell Factor of the rock (1.70), fly rocks during blasting operations and loss of aggregates during loading and haulage. The Stockpile calculated from 3D images is 44,695.39tons. The expected tonnage of the extracted rocks from the Pit after excavation and crushing into aggregates is 1,746,247.670tons, which is about 2% higher than the total aggregate produced from the Quarry by 30,447.67tons. Therefore, an allowance of approximately ±2% should be given for the expected tonnage extracted from the Pit after excavation and crushing into aggregates and the total aggregates produced from the Quarry.