Environmental geological issues such as mine land resource destruction, environmental pollution, landslides, and debris flows in the Sichuan Basin geological environment area

The Sichuan Basin can be roughly divided into two parts: the inner basin and the surrounding basin. The basin is mainly composed of low hills and plains, including hilly areas in the Rongxian-Weiyuan-Longchang area, mid-low mountainous areas in the Dazhou-Dazhu-Huaying area, Xinjin-Shuangliu-Pengshan-Meishan-Hongya shallow hilly areas and Chengdu-Ziyang- Plain-hilly areas in Suining-Mianyang-Nanchong and other places. The Basin Zhou includes the middle and low mountainous areas of Guangyuan-Wangcang-Nanjiang-Wanyuan in the north, the mid-mountainous areas of Mianyang-Deyang Longmen Mountain in the west of the Basin, the mid-mountainous areas of Baoxing-Ya'an-Shimian-Leshan in the south-west of the Basin, and Gongxian-Gaoxian-Jun in the south of the Basin. Zhongshan District in the Lian-Xuyong-Gulin area.

The basin is dominated by natural gas, coal, salt minerals and pyrite. In addition, there are non-metallic minerals for building materials. There is Dahongshan Glauber's Salt Mine in the basin, which is one of the three largest Glauber's Salt bases in my country. The rest are mostly small and medium-sized mines. The main mining environmental geological problems are occupation, destruction of land resources, landslides, debris flows, ground subsidence geological disasters and environmental pollution. According to incomplete statistics, the annual wastewater output of the mines in the basin is 3606.36×104m3, the cumulative amount of waste residue piled up is 2682.94×104t, and the land resource area occupied and destroyed is 769.63hm2. Coal mines in this area have prominent environmental geological problems. For example, in Xinmin Coal Mine in Lu County, the goaf area reaches 4hm2, and the surface damage area is about 8hm2. The groundwater level in the area has dropped, springs have stopped flowing, well water has dried up, and the ground surface has cracked and collapsed. Endangering the lives and property of local people; in Ziweilong Coal Mining Area, large areas of goaf have caused geological disasters such as ground subsidence and landslides, a large amount of waste residue and coal gangue occupy farmland, block rivers, and mine wastewater pollutes water sources and other environmental geological problems; Dazhu Coal mining areas have environmental problems such as landslides, collapses, ground fissures, coal gangue spontaneous combustion, and groundwater depletion, causing damage to farmland, roads, bridges, and houses and casualties; Huayingshan Coal Mine waste residue and wastewater are discharged indiscriminately, causing serious pollution and destruction Land and water bodies have caused siltation of rivers, depletion of groundwater, depletion of drinking water, and geological disasters such as surface collapse and cracking. Non-metallic building materials mines occupy and destroy land resources significantly, causing damage to landscape resources along transportation lines.

The area around the basin is dominated by phosphate mines, coal mines, pyrite, lead-zinc mines, placer gold mines, and non-metallic minerals for building materials (limestone, basalt, and granite). The geological problems caused by the mining environment are mainly ground subsidence, Ground fissures, massive occupation, destruction of land resources, and serious deterioration of the ecological environment. According to incomplete statistics, the annual output of mine wastewater in this area is 3796.60×104m3, the cumulative amount of ore stacked is 9005.64×104t, and the land resource area occupied and destroyed is 73760.77hm2. The mining environment and geological problems of coal mines in this area are also prominent. For example, in the Guangwang Coal Mine in the north, the goaf area has caused large-scale ground subsidence, surface cracking, and produced geological disasters such as landslides; the mining of Permian coal and phosphorus in the middle section of Longmen Mountain has formed Large-area, multi-level goafs have formed numerous dangerous rocks on the surface, inducing collapses, landslides, debris flows, lowering of groundwater levels, and destruction of vegetated cultivated land; the Furong Coal Mine in Pennan, where Permian coal is mined, has triggered more than 20 landslides and debris flows. There were 3 ground subsidences, dozens of cracks, and 15 collapses, resulting in dry farmland, barren land, depleted springs, cracked houses, and environmental pollution; in the Gulin-Xuyong coal and sulfur mining area, large areas of goaf caused ground cracks. , subsidence, slopes forming dangerous cliffs, collapses and other geological disasters. The tailings piles formed by mineral processing raise the river bed and block the river channels. Surface water, groundwater and air are all polluted. In the placer gold mines in the middle reaches of the Jialing River in the Guangyuan area, river beaches and terraces have been severely cut away. Tailings and waste rocks are piled on the riverside, filling up the river bed and destroying cultivated land, protective forests and waterways.

The Anxian Limestone Mine in the middle section of Longmen Mountain mines Permian and Triassic limestone, strips thousands of hectares of vegetation and cultivated land, causes serious water and soil erosion, and blocks rivers and valleys with slag, seriously affecting the Anxian Bioreef National Geopark; Pengzhou The "Feilaifeng" limestone and coal mine, due to hundreds of small mines competing for mining, has caused serious damage to the ecological environment and affected the landscape of the Longmen Mountain National Geopark; the Ya'an Guoba Stone Mine in Penxi, which mines pre-Sinian marble and granite, Due to extensive mining, the wasteland rate is low, waste rocks accumulate in large quantities, some rivers are silted up, and ravines are blocked, triggering debris flows and raising river beds, threatening the safety of downstream villages and counties.