Longwall Mining Automation--The Shearer Positioning Methods between the Longwall Automation Steering Committee and China University of Mining and Technology  
[PERSON]  
1 School of Mechanical and Electronic Engineering, China University of Mining and Technology,  
Xuzhou 221116, China; [EMAIL_ADDRESS] (W.D.); [EMAIL_ADDRESS] (S.W.)  
[PERSON]  
2 School of Mechanical Engineering, Yanshan University, Qinhuangdao 066004, China 22221168 22211  
mining automation technology has shown significant potential to achieve those goals through providing shearer positioning, face alignment, horizontal control, seam tracking, visualization and monitoring, and remote control [5; 6]. Among them, shearer positioning is a foundational aspect of the autonomous mining operation, and it is a key technology that enables face alignment and horizontal control. Therefore, the accurate positioning of the shearer is of great significance to longwall mining automation.  
As early as 2001, the Commonwealth Scientific and Industrial Research Organization (CSIRO) of Australia began developing the longwall automation technology known as the Longwall Automation Steering Committee (LASC). LASC is the abbreviation for the research team responsible for this technology. The LASC can fix the 3D position of the shearer, maintain the straightness of the conveyor and supports, raise the shearer drum automatically, and provide 3D remote monitoring video feeds [7; 8; 9]. The technical framework is shown in Figure 2b. The latest version, LASC 2.0, has been adopted in 70% of Australia's coal mines. DBT, JOY, and Eickhoff are all licensed manufacturers of LASC. The social benefits of LASC application have contributed to reducing the number of accidents and deaths, and the costs that are avoided as a result are likely to save mining industries millions of dollars each year. In addition, improving the accuracy of longwall mining operations and reducing the amount of waste rock leads to less environmental disruption. LASC technology has great influence on the development of longwall mining automation around the world.  
In China, research on the automation of longwall mining commenced at a relatively later stage. Under the support of the National High-tech Research and Development Program (863 Program) and the National Natural Science Foundation of China, our research group at China University of Mining and Technology (CUMT) has devoted significant  
Figure 1: The diagram of the shearer, AFC, and roof support system.  
Figure 2: The diagram of (**a**) the development stage of LASC [6] and (**b**) the technical framework of LASC.  
efforts to the longwall mining automation. Figure 3 shows the technical framework developed by CUMT for this purpose. The digital model of a coal seam is constructed using drill geological data and the seismic CT detection technique. Combining the digital model of the coal seam, shearer positioning technology is employed to obtain the shearer 3D positioning within the coal seam [10]. Based on this, it is possible to achieve AFC trajectory straightening and shearer cutting path planning. The industrial test was carried out and demonstrated satisfactory performance.  
Whether it is for LASC or CUMT, the shearer positioning method plays an important role in longwall mining automation. The shearer inertial navigation system, the measurement of longwall retreat and creep displacement, and the backward calibration of shearer trajectory are three crucial technologies to acquire the shearer's accurate positioning. Therefore, this paper aims to present an overview of three technologies utilized by the LASC and CUMT, and compares the backward calibration methods proposed by the LASC and CUMT through a conducted experiment.