Study on subsidence monitoring technology using terrestrial 3D laser scanning without a target in a mining area: an example of Wangjiata coal mine, China

When using a Terrestrial 3D laser scanning (TLS) to monitor the mining subsidence in a mining area, the conventional methods are to set up the public target manually, or to set up the ground control network in advance. However, these have the disadvantages of high labor intensity and low efficiency. In order to overcome the shortcomings of the conventional methods, this paper presents the subsidence monitoring method using TLS without a target in the mining area. Feature points are used to splice the multi-station point clouds in the same phase, and a few station coordinates are used to uniformly transform the multiphase data into a geodetic coordinate system. Afterwards, the surface digital elevation model (DEM) is established by using the point clouds after coordinate transformation, and the dynamic subsidence value and subsidence basin during the period of observation are obtained by DEM subtraction. Compared to traditional methods, this method simplifies the field measurement process, reduces the labor intensity, and transfers the main work to the internal industry. It is suitable for surface subsidence monitoring with a harsh external environment and complicated topographic conditions. Surface deformation values are important basic data for mining area subsidence parameters acquisition, mining area environmental assessment, land reclamation, and ecological restoration. As a consequence, it is of great value to popularize and apply in mining area for subsidence monitoring.