Land Subsidence Related to Coal Mining in China Revealed by L-band InSAR Analysis.

Liping Zheng,Wei Wang,Lin Zhu,Lin Guo,Beibei Chen

doi:10.3390/ijerph17041170

Abstract

Geological disasters, including ground deformation, fractures and collapse, are serious problems in coal mining regions, which have threatened the sustainable development for local industry. The Ordos Basin is most known for its abundant coal resources. Over-mining the underground coal resources had induced land deformation. Detecting the evolution of the land deformation features and identifying the potential risk are important for decision-makers to prevent geological disasters. We analyzed land subsidence induced by coal mining in a 200 area in the Ordos Basin for the time period 2006–2015. ALOS-1 PALSAR images from December 2006 to January 2011 and ALOS-2 PALSAR-2 images from December 2014 to July 2015, optical remotely sensed images and coal mining information were collected. The small baseline subset interferometric synthetic aperture radar (SBAS-InSAR) method and differential interferometric synthetic aperture radar (D-InSAR) method, GIS and statistical analysis were adopted. Results show that the maximum subsidence rate and cumulative subsidence along the line of sight (LOS) were −65 mm/year and −246 mm, respectively, from December 2006 to January 2011. The maximum cumulative subsidence was −226 mm from December 2014 to July 2015. The new boundary of the mining goafs from 2014 to 2015 and the most dangerous risk region were mapped. Moreover, the effect of large-scale mining coal, with the production volume exceeds 1.2 million tons per year, with the operation time more than 20 years on land subsidence was found greater than small and medium-scale coal mines and reached −59 mm/year. The recently established small-sized and medium-sized coal mines show high land subsidence. This study will contribute to better understand the land subsidence process in mining region and provide scientific support for government to prevent land subsidence.

Highlights

Coal is the most important primary energy source, accounting for more than 70% of total primary energy consumption in China [1]
The results indicate that large coal mine factories operating more than 20 years are more likely to induce land subsidence in this region
Two periods of land subsidence were obtained by InSAR interpretation and the dangerous risk regions from 2014 to 2015 were deduced, according to the subsidence gradient map from 2006 to 2011

Summary

Introduction

Coal is the most important primary energy source, accounting for more than 70% of total primary energy consumption in China [1]. According to the National Bureau of Statistics, China’s coal production in 2016 was 3.41 billion tons, accounting for 45.7% of the world’s total output. Ordos, located in Inner Mongolia, China, is one of the important locations for super coal mines. In 2018, the production of coal in Ordos reached 616 million tons. Along with a large number of coal mining regions in Ordos, ground fissures, ground collapse and land subsidence have undermined the land surface ecosystems [2]. In Yongcheng City, located in Henan Province, another region in China with abundant coal resources, land subsidence and ground collapse are two geological phenomena that have occurred [3]. Ground collapse is identified due to land deformation of

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Discussion

Conclusion