Evaluating the Feasibility of Illegal Open-Pit Mining Identification Using Insar Coherence

Peng Jia,Xiaoping Lu,Guo Zhang,Zhenwei Chen,Taofeng Ma,Shunyao Wang,Beibei Li

doi:10.3390/rs12030367

Abstract

Illegal open-pit mining causes environmental harm and undermines sustainable development. Conventional monitoring approaches such as field research and unmanned aerial vehicle (UAV) imagery are time-consuming and labor-intensive, making large-scale monitoring difficult. In comparison, optical remote sensing imagery can cover large areas but is vulnerable to adverse weather conditions and is not sensitive to vertical ground changes. As open-pit excavation causes sudden changes in the scattering properties of ground objects along with dramatic vertical deformation, we evaluated the feasibility of using interferometric synthetic aperture radar (InSAR) coherence to identify illegal mining activities. Our method extracts the coherence coefficient from two SAR images taken on different dates, applies thresholding and filtering to extract a decorrelation map, and then overlays this with legal mining boundaries and optical satellite images to identify illegal mining activities. For three test cases in southwestern Inner Mongolia, China, 49 legal mining sites were correctly detected (with an accuracy of 90.74%) as well as six illegal mining sites. Ground truthing confirmed the presence of ongoing activity at one of these sites. Our study shows that InSAR coherence is suitable for the identification of mining activities, and our method provides a new approach for the detection and monitoring of illegal open-pit mining.

Highlights

Mineral resources are an important aspect of economic development, playing an important role in urbanization, infrastructure construction, and national security [1]
With respect to the illegal mining sites we identified, five out of the six sites were located adjacent to known mining rights boundaries
Decorrelation is often a barrier to differential InSAR (DInSAR) application, we used this as an advantage for identifying active excavations related to open-pit mining

Summary

Introduction

Mineral resources are an important aspect of economic development, playing an important role in urbanization, infrastructure construction, and national security [1]. High demand has led to extensive illegal activities, such as unlicensed mining, operations in unauthorized areas, and extraction beyond permissible amounts [5,6] These practices can cause serious environmental problems while degrading national mineral resource stocks [7]. Surface change detection using optical satellite images can facilitate monitoring on a large scale, yet optical images are susceptible to adverse weather conditions as well as sun illumination. Most of these methods are two-dimensional, making it impossible to detect the vertical changes caused by open-pit mining.

Methods

Results

Conclusion