Evolution Assessment of Mining Subsidence Characteristics Using SBAS and PS Interferometry in Sanshandao Gold Mine, China

Guang Li,Fengshan Ma,Jie Guo,Yang Wan,Jia Liu,Yewei Song

doi:10.3390/rs14020290

Abstract

Ground subsidence is a common geological phenomenon occurring in mining areas. As an important Chinese gold mine, Sanshandao Gold Mine has a mining history of 25 years, with remarkable ground subsidence deformation. Mining development, life security, property security and ecological protection all require comprehension of the ground subsidence characteristics and evolution in the mining area. In this study, the mining subsidence phenomenon of the Sanshandao Gold Mine was investigated and analyzed based on Persistent Scatterer Interferometry (PSI) and small baseline subset (SBAS). The SAR (synthetic aperture radar) images covering the study area were acquired by the Sentinel-1A satellite between 2018 and 2021; 54 images (between 22 February 2018 and 25 May 2021) were processed using the PSI technique and 24 images (between 11 April 2018 and 12 July 2021) were processed using the SBAS technique. In addition, GACOS (generic atmospheric correction online service) data were adopted to eliminate the atmospheric error in both kinds of data processing. The interferometric synthetic aperture radar (InSAR) results showed a basically consistent subsidence area and a similar subsidence pattern. Both InSAR results indicated that the maximum LOS (line of sight) subsidence velocity is about 49 mm/year. The main subsidence zone is situated in the main mining area, extending in the northwest and southeast directions. According to the subsidence displacement of several representative sites in the mining area, we found that the PSI result has a higher subsidence displacement value compared to the SBAS result. Mining activities were accompanied by ground subsidence in the mining area: the ground subsidence phenomenon is exacerbated by the increasing mining quantity. Temporally, the mining subsidence lags behind the increase in mining quantity by about three months. In summary, the mining area has varying degrees of ground subsidence, monitored by two reliable time-series InSAR techniques. Further study of the subsidence mechanism is necessary to forecast ground subsidence and instruct mining activities.

Highlights

We investigated the mining-induced subsidence with time-series interferometric synthetic aperture radar (InSAR) analysis using Sentinel-1A images, examined the accuracy of the analysis by crossvalidating the results of the Persistent Scatterer Interferometry (PSI) and small baseline subset (SBAS) techniques and analyzed the patterns of the subsidence deformation within the Sanshandao Gold Mine over the period between 2018 and 2021
The LOS velocity value produced by PSI is a relative value, this explains subsidence may be bounded by the F3 fault (Figure 2)
The outcome of the SBAS analysis demonstrated deformation extends along the northwest and southeast direction, similar to an oblique that the mining area shows a maximum subsidence velocity in LOS of about 49 mm/year egg in shape (the same part is outlined by a solid, yellow, rectangular line in Figure 1, (Figure 7)

Summary

Introduction

Ground subsidence has caused growing ecological problems and social stability concerns worldwide. As a common geological phenomenon, it is driven by the soil type, hydrogeological conditions, bedrock configuration, tectonic faults and human activities [1,2,3,4,5]. Ground subsidence induced by the groundwater table lowering is related to the external loading that varies with time. Different types of soil (sand, silt, clay, gravel, etc.) have distinct compressibility and hydraulic conductivity [6,7,8,9]; soil thickness affects settlement. Under the action of external loading, soils with different properties will have different mechanical responses

Methods

Results

Discussion

Conclusion