Ground deformations associated with underground coal-mining observed by Sentinel-1 SAR images in vegetated area

2020 ◽  
Author(s):  
Yonghong Zhang ◽  
Hong’an Wu ◽  
Yong Luo ◽  
Yonghui Kang ◽  
Hongdong Fan
Keyword(s):  
Winter Wheat ◽  
Coal Mining ◽  
Large Scale ◽  
Central Government ◽  
Underground Mining ◽  
Mining Area ◽  
Least Square ◽  
Whole Process ◽  
Ground Deformations ◽  
Multi Temporal

<p>Coal is the largest energy source for China, and over 90% coal production in China is from underground mining. However, underground mining usually trigger large-scale ground deformations, which tend to develop as hazards. Therefore, the central government of China issued the “green mine” policy in 2017, which requires to strictly implement scientific and orderly exploitation and keeping the disturbance to the mining area and surrounding environment within the limits of sustainable development in the whole process of coal mining. This policy necessitates accurate monitoring of ground deformations induced by underground mining. Satellite Interferometric SAR (InSAR), especially the multi-temporal InSAR techniques have been successfully used to monitor deformations associated with underground mining. But temporal decorrelation still remains a big challenge because many underground mining takes place beneath farmland or forested region. Given the advantages of Sentinel-1 (S-1) in short revisit time, small baselines and free accessibility, underground mining deformations can be monitored somehow with S-1 InSAR in vegetated areas. In this research we report such an application in an underground coal-mine site located in Xuzhou, Jiangsu province of China. Four working panels are investigated</p><p>The working panels are all beneath farmland where winter wheat is sowed before the end of October and reaped around next late May, then corn or rice is planted during the coming summer season from June to September. Therefore the C-band S-1 interferograms can keep good coherence only when both images are acquired in the period of late October to next early April (this period is called coherent period thereafter) when the newly planted winter wheat is in its early growing stage. Three subsets of S-1 images acquired during three consecutive coherent periods  are used to generate mining-induced ground deformations.</p><p>During each coherent period, all of the interferograms with 12-day separation and some of the interferograms with 24-day separation and good coherence are selected and phase-unwrapped. Then these two sets of unwrapped interferograms are stacked, and finally the temporal deformations along SAR line-of-sight (LOS) are calculated under the least square principle. The temporal and spatial characteristics of the LOS deformation time series (DTS) are analyzed by considering extraction stage and extraction parameters of the working panel. Based on the analysis, we can diagnose whether the underground exploitation overstepped its designed boundary, or whether the working panel has been exploited for longer time than the designed extraction period.</p><p> </p>

scholarly journals Water Preservation and Conservation above Coal Mines Using an Innovative Approach: A Case Study

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2818
Author(s):  
Yujun Xu ◽  
Liqiang Ma ◽  
Yihe Yu
Keyword(s):  
Coal Mining ◽  
Water Conservation ◽  
Large Scale ◽  
Influencing Factor ◽  
Mining Area ◽  
Mining Operations ◽  
Narrow Strip ◽  
Geological Conditions ◽  
The Impact

To better protect the ecological environment during large scale underground coal mining operations in the northwest of China, the authors have proposed a water-conservation coal mining (WCCM) method. This case study demonstrated the successful application of WCCM in the Yu-Shen mining area. Firstly, by using the analytic hierarchy process (AHP), the influencing factors of WCCM were identified and the identification model with a multilevel structure was developed, to determine the weight of each influencing factor. Based on this, the five maps: overburden thickness contour, stratigraphic structure map, water-rich zoning map of aquifers, aquiclude thickness contour and coal seam thickness contour, were analyzed and determined. This formed the basis for studying WCCM in the mining area. Using the geological conditions of the Yu-Shen mining area, the features of caved zone, water conductive fractured zone (WCFZ) and protective zone were studied. The equations for calculating the height of the “three zones” were proposed. Considering the hydrogeological condition of Yu-Shen mining area, the criteria were put forward to evaluate the impact of coal mining on groundwater, which were then used to determine the distribution of different impact levels. Using strata control theory, the mechanism and applicability of WCCM methods, including height-restricted mining, (partial) backfill mining and narrow strip mining, together with the applicable zone of these methods, were analyzed and identified. Under the guidance of “two zoning” (zoning based on coal mining’s impact level on groundwater and zoning based on applicability of WCCM methods), the WCCM practice was carried out in Yu-Shen mining area. The research findings will provide theoretical and practical instruction for the WCCM in the northwest mining area of China, which is important to reduce the impact of mining on surface and groundwater.

scholarly journals Study on the Law of Surface Cracks While Coal Mining in the Thin Bedrock and Thick Unconsolidated Layer of Yu-Shen-Fu Mining Area

2018 ◽  
Vol 53 ◽  
pp. 03040
Author(s):  
Wu Zuoqi ◽  
Wang Guoku ◽  
Zhao Liqin
Keyword(s):  
Coal Mining ◽  
Ground Surface ◽  
Mining Area ◽  
Dynamic Evolution ◽  
Surface Cracks ◽  
Whole Process ◽  
Thin Bedrock ◽  
The Law ◽  
Mining Face ◽  
Overlying Strata

The law of surface cracks caused by coal mining in ther thin bedrock and thick unconsolidated layer was studied in Yu-Shen-Fu mining area. The crack development in the overlying strata of the coal mining face was detected by drilling survey technology, the whole process of the ground surface crack dynamic evolution was carried out by similar material simulation, and the law of surface cracks evolution was verified by on-site tracking measurement. The study reached the regulation of the overlying strata failure and dynamic evolution of surface cracks caused by coal mining under thin bedrock and thick unconsolidated layer in Yu-Shen-Fu mining area, which can provide theoretical support for the ecological restoration of western mining area.

Tracking the Land Use/Land Cover Change in an Area with Underground Mining and Reforestation via Continuous Landsat Classification

2019 ◽  
Vol 11 (14) ◽  
pp. 1719 ◽  
Author(s):  
Jiaxin Mi ◽  
Yongjun Yang ◽  
Shaoliang Zhang ◽  
Shi An ◽  
Huping Hou ◽  
...  
Keyword(s):  
Land Use ◽  
Random Forest ◽  
Land Cover ◽  
Large Scale ◽  
Underground Mining ◽  
Mining Area ◽  
Random Forest Classifier ◽  
Land Use Land Cover ◽  
Lulc Change ◽  
Mining Areas

Understanding the changes in a land use/land cover (LULC) is important for environmental assessment and land management. However, tracking the dynamic of LULC has proved difficult, especially in large-scale underground mining areas with extensive LULC heterogeneity and a history of multiple disturbances. Additional research related to the methods in this field is still needed. In this study, we tracked the LULC change in the Nanjiao mining area, Shanxi Province, China between 1987 and 2017 via random forest classifier and continuous Landsat imagery, where years of underground mining and reforestation projects have occurred. We applied a Savitzky–Golay filter and a normalized difference vegetation index (NDVI)-based approach to detect the temporal and spatial change, respectively. The accuracy assessment shows that the random forest classifier has a good performance in this heterogeneous area, with an accuracy ranging from 81.92% to 86.6%, which is also higher than that via support vector machine (SVM), neural network (NN), and maximum likelihood (ML) algorithm. LULC classification results reveal that cultivated forest in the mining area increased significantly after 2004, while the spatial extent of natural forest, buildings, and farmland decreased significantly after 2007. The areas where vegetation was significantly reduced were mainly because of the transformation from natural forest and shrubs into grasslands and bare lands, respectively, whereas the areas with an obvious increase in NDVI were mainly because of the conversion from grasslands and buildings into cultivated forest, especially when villages were abandoned after mining subsidence. A partial correlation analysis demonstrated that the extent of LULC change was significantly related to coal production and reforestation, which indicated the effects of underground mining and reforestation projects on LULC changes. This study suggests that continuous Landsat classification via random forest classifier could be effective in monitoring the long-term dynamics of LULC changes, and provide crucial information and data for the understanding of the driving forces of LULC change, environmental impact assessment, and ecological protection planning in large-scale mining areas.

scholarly journals Ecological Environment Changes of Mining Areas Around Nansi Lake With Remote Sensing Monitoring

2021 ◽  
Author(s):  
Hu Liu ◽  
Yan Jiang ◽  
Rafal Misa ◽  
Junhai Gao ◽  
Mingyu Xia ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Coal Mining ◽  
Large Scale ◽  
Underground Mining ◽  
Water Area ◽  
Ecological Environment ◽  
Support Vector ◽  
Svm Classifier ◽  
Nansi Lake ◽  
The Impact

Abstract Underground mining activity has existed for more than 100 years in Nansi lake. Coal mining not only plays a supporting role in local social and economic development but also has a significant impact on the ecological environment in the region. Landsat series remote sensing data (1988~2019) are used to research the impact of coal mining on the ecological environment in Nansi lake. Then Support Vector Machine (SVM) classifier is applied to extract the water area of the upstream lake from 1988 to 2019, and ecological environment and spatiotemporal variation characteristics are analyzed by Remote Sensing Ecology Index (RSEI). The results illustrate that the water area change is associated with annual precipitation. Compared with 2009, the ecological quality of the lake is worse in 2019, and then the reason for this change is due to large-scale underground mining. Therefore, the coal mines from the natural reserve may be closed or limited to the mining boundary for protecting the lake's ecological environment.

Ground motion detection in a salt solution mining area, an application of Multi-Temporal Satellite Interferometry

2021 ◽  
Author(s):  
Lorenzo Solari ◽  
Roberto Montalti ◽  
Anna Barra ◽  
Oriol Monserrat ◽  
Silvia Bianchini ◽  
...  
Keyword(s):  
Ground Motion ◽  
Salt Solution ◽  
Underground Mining ◽  
Central Italy ◽  
Mining Area ◽  
Mining Activity ◽  
Groundwater Depletion ◽  
Solution Mining ◽  
Mining Areas ◽  
Multi Temporal

<p>Subsurface mining is one of the human activities with the highest impact in terms of induced ground motion. The excavation of the mining layers creates a geotechnically and hydrogeologically unstable context. The generation of chimney collapses and sinkholes is the most evident surface consequence of underground mining which, in general, creates the optimal conditions for the development of subsidence bowls. Considering this, the need for ground motion monitoring tools is evident. Topographic measurements have been the obvious choice for many years. Nowadays, the flourishing of Multi-Temporal Satellite Interferometry (MTInSAR) algorithms and techniques offers a new way to measure ground motion in mining areas. MTInSAR fully covers the accuracy requirements asked by mining companies and authorities, adding new potentialities in term of area coverage and number of measurement points. The technique has some intrinsic limitations in mining areas, e.g. coherence loss, but the algorithms are being pushed to their technical limits in order to provide the best coverage and quality of measures.</p><p>This work presents a detailed scale MTInSAR approach designed to characterize ground deformation in the salt solution mining area of Saline di Volterra (Tuscany Region, central Italy). In summary, salt solution mining consists in the injection at the depth of interest of a dissolving fluid and in the extraction of the resultant saturated brine. In Saline di Volterra, this mining activity created ground motion, sinkholes and groundwater depletion. The MTInSAR processing approach used is based on the direct integration of interferograms derived from Sentinel-1 images and on the phase splitting between low and high frequency components. Phase unwrapping is separately performed for the two components that are then recombined to avoid error accumulation. Before generating the final deformation map, a classical atmospheric phase filtering is applied to remove the residual low frequency signal. The results obtained reveal the presence of several subsidence bowls, sometimes corresponding to sinkholes formed in the recent past. These moving areas register velocities up to -250 mm/yr with different spatial and temporal patterns according to the distribution and age of formation of sinkholes. This is the first time an interferometric analysis is performed here. It is hoped that such information could increase the awareness of local entities on the ground effects induced by this mining activity.</p>

scholarly journals Impact of coal mining on groundwater of Luohe Formation in Binchang mining area

2020 ◽  
Author(s):  
Kui Sun ◽  
Limin Fan ◽  
Yucheng Xia ◽  
Cheng Li ◽  
Jianping Chen ◽  
...  
Keyword(s):  
Coal Mining ◽  
Groundwater Level ◽  
Water Conservation ◽  
Underground Mining ◽  
Groundwater Resources ◽  
Vertical Direction ◽  
Mining Area ◽  
Aquifer System ◽  
Groundwater Levels ◽  
Spring Flow

Abstract Groundwater of Luohe Formation is the main water source for industrial and agricultural and residential use in Binchang mining area, which is one of the key elements to water conservation coal mining. However, few studies are available to document the enrichment characteristics and influence of underground coal mining on groundwater for the Luohe Formation. This study evaluates the changes of groundwater levels and spring flow caused by mining activities to explore the influence mechanism of coal mining on groundwater by comparatively analysing existing mining data and survey data combined with a series of mapping methods. The results show that the aquifer of Luohe Formation are gradually thinning south-eastwards, disappeared at the mining boundary. In the vertical direction, the lithological structure is distinct, due to alternative sedimentation of meandering river facies and braided river facies. According to the yielding property, the aquifer is divided into three sections, namely, strong water-rich section, medium water-rich section, and weak water-rich section, which are located in northwest and central part, southwest, and the rest part of the mining area, respectively. Mining of Tingnan Coal Mine since 2004 has caused a 3.16 to 194.87 meters drop in groundwater level of Luohe Formation. Until 2015, 70.10% of the mining area undergoes a groundwater level drop larger than 10.00 meters. Another influence of underground mining is that the total flow from 34 springs in 8 southern coal mines of the area has decreased by 286.48 L/s with a rate of decrease at 46.95% from 2007 to 2017. The areas that groundwater level falls or spring flow declines are manly located in the mine gob areas. Results also indicate that the ratio of the height of water conducted fracture zone to the mining height in Binchang mining area is between 16.85 and 27.92. This may increase ground water flow in vertical direction, causing a water level in the aquifer system to drop and ultimately decreasing the flow from the springs. The research results will provide data and theoretical support for the protection of groundwater resources and water conservation coal mining of Luohe Formation in Binchang mining area.

scholarly journals Empowered Community vs Dependent Community: Corporate Social Responsibility (CSR) Implications by Mining Companies in South Sumatra Province

2017 ◽  
Vol 8 (5-1) ◽  
pp. 69-78
Author(s):  
Risna Resnawaty ◽  
Keyword(s):  
Corporate Social Responsibility ◽  
Social Responsibility ◽  
Coal Mining ◽  
Central Government ◽  
Negative Impact ◽  
Mining Area ◽  
Mining Companies ◽  
The Social ◽  
Owned Company ◽  
Corporate Social

Abstract Mining business actors have an obligation to maintain the sustainability of the surrounding environment, both in the physical and the social environment. Coal mining extraction activities are closely related to the exploration and exploitation of natural resources. This activity is in contact with the interests of the surrounding community, in particular with the negative impact caused. Mining companies in Indonesia are bound by the Mineral and Coal Mining Act no. 4 of 2009 to carry out community development and empowerment. Under the law, the companies are required to implement Corporate Social Responsibility (CSR). Through the implementation of CSR is expected the company can provide a positive change for the survival of communities around the mining area. PT BARA is one of mining companies that had been implementing CSR since 1983. As a state-owned company PT. BARA has various binding regulations in the implementation of CSR. The regulation comes from the central government as well as the local government in which PT. BARA does its mining business. Every year PT BARA releases an enormous amount of CSR funds, but the surrounding community is still in a state of poverty. It turns out that the problem does not stop on poverty at all. The community becomes very dependent on the company's assistance. The purpose of the CSR program is to develop and empower the community has not been able to achieve the goal. This dependence is caused by various reasons such as CSR policies of companies as well as government and CSR implementation on society.

scholarly journals Detecting Rock Glacier Displacement in the Central Himalayas Using Multi-Temporal InSAR

2021 ◽  
Vol 13 (23) ◽  
pp. 4738
Author(s):  
Xuefei Zhang ◽  
Min Feng ◽  
Hong Zhang ◽  
Chao Wang ◽  
Yixian Tang ◽  
...  
Keyword(s):  
Deformation Rate ◽  
Large Scale ◽  
Parameters Estimation ◽  
Least Square ◽  
Rate Variation ◽  
Rock Glacier ◽  
Ridge Estimator ◽  
Central Himalayas ◽  
Multi Temporal ◽  
Rock Glaciers

Rock glaciers represent typical periglacial landscapes and are distributed widely in alpine mountain environments. Rock glacier activity represents a critical indicator of water reserves state, permafrost distribution, and landslide disaster susceptibility. The dynamics of rock glacier activity in alpine periglacial environments are poorly quantified, especially in the central Himalayas. Multi-temporal Interferometric Synthetic Aperture Radar (MT-InSAR) has been shown to be a useful technique for rock glacier deformation detection. In this study, we developed a multi-baseline persistent scatterer (PS) and distributed scatterer (DS) combined MT-InSAR method to monitor the activity of rock glaciers in the central Himalayas. In periglacial landforms, the application of the PS interferometry (PSI) method is restricted by insufficient PS due to large temporal baseline intervals and temporal decorrelation, which hinder comprehensive measurements of rock glaciers. Thus, we first evaluated the rock glacier interferometric coherence of all possible interferometric combinations and determined a multi-baseline network based on rock glacier coherence; then, we constructed a Delaunay triangulation network (DTN) by exploiting both PS and DS points. To improve the robustness of deformation parameters estimation in the DTN, we combined the Nelder–Mead algorithm with the M-estimator method to estimate the deformation rate variation at the arcs of the DTN and introduced a ridge-estimator-based weighted least square (WLR) method for the inversion of the deformation rate from the deformation rate variation. We applied our method to Sentinel-1A ascending and descending geometry data (May 2018 to January 2019) and obtained measurements of rock glacier deformation for 4327 rock glaciers over the central Himalayas, at least more than 15% detecting with single geometry data. The line-of-sight (LOS) deformation of rock glaciers in the central Himalayas ranged from −150 mm to 150 mm. We classified the active deformation area (ADA) of all individual rock glaciers with the threshold determined by the standard deviation of the deformation map. The results show that 49% of the detected rock glaciers (monitoring rate greater than 30%) are highly active, with an ADA ratio greater than 10%. After projecting the LOS deformation to the steep slope direction and classifying the rock glacier activity following the IPA Action Group guideline, 12% of the identified rock glaciers were classified as active and 86% were classified as transitional. This research is the first multi-baseline, PS, and DS network-based MT-InSAR method applied to detecting large-scale rock glaciers activity.

scholarly journals Investigation on Mining Subsidence Based on Sentinel-1A Data by SBAS-InSAR technology—Case Study of Ningdong Coalfield, China

2020 ◽  
Vol 24 (3) ◽  
pp. 373-386
Author(s):  
Fei Ma ◽  
Lichun Sui
Keyword(s):  
Deformation Rate ◽  
Large Scale ◽  
Underground Mining ◽  
Ground Deformation ◽  
Mining Area ◽  
Mining Subsidence ◽  
Maximum Deformation ◽  
Mining Areas ◽  
Short Period ◽  
Sbas Insar

Ground deformation characterization was difficult to obtain over large spatial areas before the invention of the Satellite radar interferometry (InSAR) technique. Especially underground mining in the Loess Plateau of China, it causes large-scale ground damage within a short period of time. A small baseline subset (SBAS) algorithm can overcome some limitations of InSAR technology, such as temporal decorrelation, spatial decorrelation, and atmospheric delay. In this study, SBAS-InSAR technology was applied to process 19 scenes of Sentinel-1A data in Ningdong Coalfield, China. We investigated and analyzed the mining subsidence status from March 2015 to June 2016. There are 6 ground deformation areas in the cumulative subsidence maps, and the maximum cumulative subsidence value is -178cm distributed in the Renjiazhuang mining area during this period. The deformation rate map shows that the maximum deformation rate was -117cm/year. GPS data above the working tunnel was collected in six mining areas in Shigouyi. The subsidence value of SBAS data is consistent with GPS observation station data. The results reveal the evolution process of subsidence in mining subsidence and are helpful to the early warning of the mine disaster.

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