Three-Dimensional Space-time Comparative And Micro-geomorphological Analysis Of The Open-pit Mine Based On UAV

Open-pit mining refers to remove the upper and surrounding topsoil and rock then mining the ore directly in the open-pit mine.As a production method with low cost and high production,open-pit mining accounts for an extremely important proportion in the mine exploitation in both domestic and abroad.However,some negative impacts such as the environmental pollution caused by open-pit mining and the destruction of the original geomorphology in the process of open-pit mining are underestimated.The excavation of pit or waste rock formed by open-pit mining may lead to natural disasters such as landslide,collapse and debris flow induced by human factors or natural factors.These disasters are potential threats to people and property near the mine area,how to analyze the slope and surface of open-pit mining area in time and space has become one of the urgent problems to be solved.Remote sensing,a mature earth observation technology,is an effective means to realize rapid global or regional earth observation.Low-altitude unmanned aerial vehicle(UAV)remote sensing is characterized by high efficiency,high accuracy and low cost.Through low-altitude UAV,target images can be acquired rapidly and efficiently,and then the spatial three-dimensional information of the target area can be obtained through fast processing,and finally the target area can be analyzed quantitatively with relevant professional knowledge.By UAV photogrammetry technology,the traditional open-pit mine deformation monitoring can extended from two-dimensional to three-dimensional,leveled up from single sequence space to time space sequence,so as to realize the three dimensional space-time evolution analysis of open pit mine.The research mainly achieved the following results:(1)Analyzing the working characteristics and process of the multitemporal change estimation UAV remote sensing system.(2)Introducing the 3D cloud points acquisition and processing method.(3)The principle of digital extraction of the micro-geomorphology of open pit mine and its topographic factors were analyzed.(4)Based on the above theoretical research,taking the two unmanned aerial surveys of Miyun Shouyun iron mine in Beijing as a case,the workflow of UAV aerial photogrammetry was introduced;Through the processing of the data acquired by UAV,firstly,in combination with digital orthophoto map and digital elevation model data,several kinds of micro-geomorphological factors such as slope,slope direction,curvature and surface roughness were extracted and analyzed.The change in the main mine is concentrated in the south of the mine,especially in the south of the mine,which has the artificial terrace with high incline,high curvature and high surface roughness.Then extract four types of micro-geomorphological of open-pit mine including depression,platform,slope and flat terrain.Finally,the two two-stage scintigraphy cloud data was obtained for registration,denoising and other pretreatment,after which,by using the point cloud comparison method based on the normal vector,found out that the data of the two periods changed a lot,especially in the artificial geomorphology in the southeast of the mine pit,the excavation area was 82 meters deep,and the excavation volume was more than 10 million cubic meters.Through the application case study of Beijing Miyun Shouyun iron ore mine,the feasibility and practical significance of three-dimensional space-time comparative and micro-geomorphologic analysis of the open-pit mine based on UAV are verified.