Monitoring Mining Activities Using Sentinel-1A InSAR Coherence in Open-Pit Coal Mines

Abstract

Long-term continuous monitoring of the mining activities in open-pit coal mines is conducive to planning and management of the mining operations. Additionally, this faciliatates assessment on their environmental impact and supervises illegal mining behaviors. Interferometric Synthetic Aperture Radar (InSAR) technology can be effectively applied in the monitoring of open-pit mines where vegetation is sparse and land cover is dominated by bare rock. The main objective of this study is to monitor the mining activities of four open-pit coal mines in the Wucaiwan mining area in China from 2018 to 2020, namely No. 1, No. 2 (containing two mining areas), and No. 3. We use the normalized differential activity index (NDAI) based on the coherence coefficient as an indicator of the mine activity due to its robustness to temporal and spatial decorrelation. After analyzing and removing the decorrelation caused by rain and snow weather, 70 NDAI images in 12-day intervals are obtained from Sentinel-1A InSAR coherence images. Then, the annually-averaged NDAI images are applied to an RGB composite technique (red for 2018, green for 2019, blue for 2020) to express the interannual variation of the mining activities. Points of interest are then selected for NDAI time series analysis. The RGB composite results indicated that No. 1 and 3 open-pit coal mines were continuously mined during the three years; whereas, the two mining areas of No. 2 were mainly active in 2018. The 12-day NDAI time-series graphs of No. 2 open-pit coal mine also indicate that the coal piles located in the coal transferring area of the first mining area were not completely removed until April 2019. It is also seen that the second mining area was decommissioned in November 2018 and became rehabilitated in July 2019. Results were validated using the Sentinel-2A images and related background information confirming the efficiency of the proposed approach for monitoring the mining activity in open-pit mines.

Time Series Insar Analysis for Slope Stability Monitoring Using Sentinel-1 in Open Pit Mining

“…Sentinel-1 offers global covers and provides SAR data at regular intervals. This has been used in various applications including slope failures and mining-related deformation (Carla et al, 2019;Tang et al, 2020;Wang et al, 2021). The role of open-access Sentinel-1 data enables collaboration between various users (Ramachandran et al, 2021).…”

Ground Surface Subsidence Monitoring Using Sentinel-1 in the “Kostolac” Open Pit Coal Mine

“…Currently, MT-InSAR techniques are developed to monitor large areas such as the whole territory of Germany [46], Norway [47], and Italy [48], or as an alpha version of an infrastructure monitoring and decision-support framework remotIO based on the MT-InSAR introduced by Bakon et al [49]. Many studies showed subsidence results for cities in Europe [2,3,50], the USA [45], and China [51], or of deformation monitoring of earthquakes [4,52], min-ing [22,30,31,53], land and coastal monitoring [2,3,7,23,[39][40][41]54], volcanic activities [55], glacier motions [56], or even illegal mining activities using the decorrelation problem as valuable information [53]. In addition, by combining dual polarization channels VV and VH, the Polarimetric Persistent Scatterer Interferometry technique (PolPSI) can be used to reduce decorrelation effects and achieve better deformation monitoring [57].…”

Land Use Dynamic Evolution and Driving Factors of Typical Open-Pit Coal Mines in Inner Mongolia

“…Because of the late start of the monitoring technology, immature monitoring methods and low-accuracy monitoring results are frequent [ 39 , 40 ]. However, this phenomenon gradually decreases with the improvement of the research methods.…”