Monitoring tram rail transport in underground coal mines using terrestrial laser scanning

Tram rail transport is one of the important transport systems in underground coal mines. The stability of the tramway system in a mine is influenced by many factors, such as geological and mining conditions. In order to evaluate the stability of tramway tracks in underground coal mines, monitoring activities are carried out periodically. This activity is to provide accurate data on the current status of the rail system, early detection of displacement and deformation of the system. This paper presents the results of monitoring tram tracks in underground coal mines by the terrestrial laser scanning technology (TLS). The objective of the study are to evaluate the capacity of TLS in monitoring tram tracks in underground coal mines, and to propose a workflow for this activity. The experiment was held at the tramway in the main transport tunnel at the level of -350 m in the Nui Beo underground coal mine. A procedure was proposed, including the planning, collecting data in the field, data processing, and analyzing data. The surveing equipment was used, including: (1) a Topcon GLS 2,000 scanner for the TLS survey, (2) Digital leveling for measuring the elevation of the rails, (3) a tape for measuring the distance between the rails. The measurement of the distance between two railway lines were performed on the TLS point cloud. The comparison between TLS and the tape showed that the maximum difference was less than 3 mm and met the requirements of the monitoring of tram tracks in underground coal mines.