Risk Assessment And Early Warning Of Eco-geological Environment Induced By High Intensity Mining In Ningdong Coal Base

Energy is closely related to national economic development and national security.Coal resource mining has laid a solid foundation for China’s high-quality economic,social development and social harmony and stability.The service function and service effect of ecological geological environment have been affected seriously with the intensive exploitation of coal resources in the ecologically fragile areas of Western China.Aiming at the ecological geological environment problems caused by high-intensity mining of coal resources in Ningdong coal base,study of ecological geological environment service function evaluation and ecological geological environment risk evaluation and early warning research have carried out based on dynamic monitoring of surface deformation,investigation of land use types,investigation of surface vegetation coverage in coal mining subsidence area through multi-source monitoring technologies such as long-time sequence radar remote sensing,optical remote sensing,GNSS and UAV aerial photography.The results provide scientific technical means and theoretical support for improving the reliability of geological environment risk evaluation and early warning of high-intensity coal mining and ecological geological environment protection and restoration.The main research contents are as follows:1.In view of the fact that high mining intensity,large mining area and wide goaf range in Ningdong coal base,the strategy of combining GNSS automatic monitoring and manual monitoring is adopted,72 sets of high-precision automatic GNSS field monitoring stations and 79 sets of manual monitoring stations are installed.It is the first GNSS monitoring network for surface deformation in coal mining subsidence area of large coal base in Northwest China.A set of surface deformation monitoring system has been developed;Integrating with radar remote sensing,optical remote sensing,GNSS,UAV aerial photography and manual measurement,a space-air-ground integrated dynamic monitoring system for surface deformation in coal mining subsidence area is established.Aiming at the problem of the noise impact of GNSS monitoring data of surface deformation,a GNSS monitoring data processing technology based on the segmented Kalman filtering method is proposed,and the value after differential filtering is used to correct the monitoring data.The results of the segmented Kalman filtering of the GNSS monitoring data from 2015 to 2020 in Jinfeng Coal Mine show that the segmented Kalman filter method reduces the adverse effects of noise in the rapid deformation process of the ground surface and improves the accuracy of the GNSS monitoring results.2.Based on Bayesian statistical theory,Helmert variance component is introduced to construct adaptive Bayesian estimation.GNSS-INSAR monitoring data fusion is realized by optimizing the weight ratio of GNSS prior information and LOS directional observation information;Utilizing the LOS to surface deformation obtained by INSAR and the three-dimensional surface deformation data obtained by GNSS to establish a probabilistic integration-genetic algorithm ground deformation parameter inversion model based on the GNSS-INSAR fusion monitoring results,which can effectively avoid traditional subsidence and horizontal movement parameter inversion The phenomenon of fragmentation improves the use efficiency of monitoring data and the accuracy of parameter inversion.3.Through the long-term time from 1980 to 2020 of land use types in Ningdong coal base interpretated from remote sensing image,the land use types and their temporal and spatial evolution laws in 10 periods of Ningdong coal base are analyzed,and verified by UAV aerial photography interpretation.In terms of 1980 to 2020,the urban and rural,industrial and mining land of Ningdong coal base increased year by year,the grassland,woodland decreased year by year,and the cultivated land area decreased sharply and then stabilized,indicating that the infrastructure construction of Ningdong coal base increased,the construction land increased and the grassland,woodland decreased.The area of forest land increased first and then decreased.Water body,industrial and mining enterprises and construction land show an increasing trend with the increase of coal production.Spatially,with the mining activities and the construction of energy and chemical industry base,the land use type in Ningdong coal base has changed,mainly from grassland and forest land to construction land.The vegetation coverage in Ningdong coal base reached the maximum in 2012,and then decreased year by year,and the decline range of vegetation coverage within the mining right is greater than that of the whole Ningdong coal base.The data analysis shows that the vegetation coverage decreases with the increase of annual coal production.The research results provide data support for the ecological geological environment service function and service value accounting of Ningdong coal base.4.Combined with the characteristics of eco-geological environment of Ningdong coal base,a calculation scheme of eco geological environment service function driven by remote sensing data is designed based on long-term remote sensing monitoring and interpretation data,various eco-geological environment data such as hydrology,meteorology,and environment.The scheme contents five eco-geological environment service functions such as climate regulation,wind prevention and sand fixation,carbon fixation and oxygen release water conservation and soil conservation,which are the main research elements to evaluate the temporal and spatial evolution law of eco-geological environment service function of Ningdong coal base.The results show that an overall improvement trend from 2001 to 2019,among which the functions of climate regulation,carbon fixation and oxygen release,wind prevention and sand fixation have a significant improvement trend,and most of the functions of soil conservation and water conservation remain basically unchanged.The strength of ecological service function is closely related to the spatial distribution of coal mining.Far away from the coal mining area,the ecological geological environment service function is strong,on the contrary,it is weak.After accounting,the total value of eco-geological environment services in Ningdong coal base showed an upward trend of fluctuation from 2001 to 2019.The research results provide eco-geological environment service capacity data for eco-geological environment risk assessment and early warning research of high-intensity coal mining in Ningdong.5.Based on the evaluation criteria,fully consider the eco-geological environmental conditions of Ningdong coal base,the impact of human engineering activities and the mineral resources planning of Ningxia(2021-2025),explore and put forward the"three map double prediction method"for eco-geological environment risk assessment of Ningdong Coal high-intensity mining,which refers to the zoning map of eco-geological environment vulnerability.The ecological geological environment service function zoning map and the impact zoning map of human engineering activities refer to the ecological geological environment risk prediction of the mining area under the condition of whether the green mine construction policy is implemented from 2021 to2025.Aiming at the problem of mine eco-geological environment risk assessment,the thesis constructs an eco-geological environment risk assessment index system of Ningdong coal base with 3 first-class indexes,10 second-class indexes and 35third-class indexes,determines the weight of each index by analytic hierarchy process,and finally obtains the eco geological environment risk zoning map of Ningdong Coal base.The analysis results show that under the current conditions,the area of extremely high risk area,high risk area,medium risk area and low risk area of Ningdong coal base are 265.95 km~2,269.29 km~2,441.79 km~2 and 2313.48 km~2 respectively;If the green mine construction policy is strictly implemented,the impact of human engineering activities on the ecological geological environment in the mining area will reduce,the area of high-risk area and high-risk area of ecological geological environment will reduce correspondingly,so the risk of ecological geological environment will be reduced significantly.6.Based on the results of eco-geological environment risk assessment,the eco-geological environment risk early warning model is constructed,four risk levels are formulated as red,orange,yellow and blue.The different information receiving objects are determined of different early warning levels.The eco-geological environment risk early warning function of Ningdong coal base is realized preliminarily,which provide scientific basis for repair and supervision so as to strengthen the eco-geological environment protection for government functional departments and mining enterprises.