Monitoring of Ground Surface Deformation of Mining Area by using inSAR Techniques, a Case Study of Midroc Lega Dembi Gold Mine Shakiso, Ethiopia
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Date
2022-02
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Addis Ababa University
Abstract
Ground surface deformation caused by mining activity is a critical aspect when assessing safety
of slope and environmental impacts due to the operations of open-pit and underground mining.
These mining-induced ground surface deformations have the potential to seriously harm the
environment, slope stability, and man-made structures in the mining activity area and this problem
monitored by using either ground or space monitoring systems. Traditional or Ground methods of
monitoring ground surface deformation in the mining operations region are laborious, expensive,
and time consuming with in the areas that being difficult to access. Remote sensing and other
geospatial observations enable a cost-effective, dependable, temporally and spatially continuous
monitoring process of mining operations at enormous sizes, regardless of physical accessibility.
In this study, C-band SAR data were used to demonstrate the possibility of using the Persistent
Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) technique to investigate ground
surface deformation induced by mining activities, specifically in the Midroc Gold Mine Company.
The PSInSAR approach also has demonstrated its potential to analysis time series of ground
subsidence in having dense vegetation and rural behavior of the study area. In midroc lega dembi
open pit mining area, the maximum rate of ground surface deformation was −90 mm/year with a
cumulative subsidence value of −200 and −100 mm were observed from InSAR techniques and
−3.99866 and −0.000122 m cumulative displacement were observed from ground survey data.
This large discrepancy between datasets is likely the result of dense vegetation land cover in the
area of the interest. The ground survey data of the Midroc lega Dembi open pit mining region was
correlated with the PS-InSAR results, revealing subsidence spots with a value of 0.98 correlation
coefficient in selected point. The selected methodology of using C-band SAR data and ground
survey data with PS-InSAR techniques to identify, monitor, and map ground surface deformation
in the Gold mine area was practically applicable. Finally, based on the results and findings on the
present study, certain recommendations has been made.
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Keywords
Ground Subsidence, Open pit mining, Persistent Scatters (PS), Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR)