I. Present situation of mine geological environment and main environmental problems
(A) the destruction and occupation of land resources
There are many pits in various mining areas in lingbao city, which are distributed along valleys. There are many people and sheds in the mining area. Mining waste piles are mostly transported along hillsides or short distances, and piled up in large quantities near various mines. According to incomplete statistics, the accumulated storage waste of various mines is 25.808 million tons, of which the storage waste of gold mines is18.849 million tons, accounting for 73.0%. There are 3/kloc-0 tailings ponds in gold mines and pyrite mines, and the existing tailings amount is 1.57 1.200 tons. During the years of mine production, a large amount of slag accumulated in valleys and rivers, which not only occupied and destroyed a lot of land, but also seriously damaged a lot of forestry resources, causing great damage to the ecological environment of the mining area and its surrounding areas. It is conservatively estimated that the land area destroyed and occupied by mining is about 45,000 mu. At present, the tailings pond * * * covers an area of nearly 7500 mu; The area affected by dust hazards is about 7.68 million square meters.
(2) Ground collapse, ground fissure, collapse and landslide in goaf.
Some mining areas in China have steep terrain, numerous cliffs, developed faults and broken rocks. Due to the influence of gravity, the natural collapse of cliffs occurs from time to time. For example, there was a huge cliff collapse in Yuchuchagou, Zaoxiang, where huge stones collapsed instantly and the ground shook. The collapse of coal miners and sheds in the valley will cause casualties and property losses. In addition, the destruction of natural slopes by mining and road construction in various mining areas and artificial cliffs formed by slope cutting are the main places for mine collapse. For example, 1996 Sifangou collapsed, resulting in the destruction of the Jin Jiu Armed Police Detachment 1 field exploration base, resulting in the death of two members.
Four mining-induced landslides have been found, which pose a great threat to the safety of life and property of the mining area itself and surrounding residents. For example, there are two landslides in Dahukou landslide area of Yangping town, namely Xishan landslide and Dongshan landslide. Dongshan landslide occurred in June 1 987165438+1October1,with a volume of 40× 104 cubic meters, resulting in three deaths and direct economic losses of more than 7 million yuan. Ground fissures caused by mining are mostly found at the edge of ground subsidence, the rear edge of landslide and the vicinity of landslide caused by slag pile collapse and slag slope instability, which endangers the property safety of nearby residents' houses, sheds and roads.
(3) Slag slope instability, tailings dam failure and debris flow.
Slag produced by years of underground tunnel mining in various mining areas in lingbao city accumulates in various valleys along the hillside. Many mining areas have steep terrain and narrow valleys, which have accumulated over time. The accumulation height of slag slope is too high and the slag pile is too large, especially in some valleys and mining areas.
Most of the tailings ponds in mines in China are located in valleys or loess gullies, and most of the concentrator is surrounded by farmland and residential areas, which not only occupies a lot of land, but also leads to the continuous decrease of land in the reservoir area and the continuous deterioration of the ecological environment near the reservoir area due to the accumulation of tailings. Dust is often formed in the dry season of tailings pond, which affects the surrounding people and harms the land near the reservoir area. At the same time, the existence of tailings ponds has laid a major hidden danger of dam failure, posing a threat to the lives and property of downstream residents.
There are 22 debris flow gullies and 9 moderately prone debris flow gullies. The characteristics of debris flow development are: sudden outbreak, fast movement, large energy and strong destructiveness, which often causes great harm to people's lives and property, and the degree of harm is generally significant or extraordinarily serious. 1In July, 1998, a mudslide disaster occurred in Wenyugou Wenyu Gold Mine, which destroyed roads 16 kilometers, bridges and culverts 10, transformers, air compressors and other large mechanical equipment, power supply and communication in the mining area were interrupted, and the mining area stopped production, resulting in economic losses of 4.73 million yuan.
(d) disruption of water balance
Due to the production and development of several gold mines in lingbao city for many years, most of the mountains in the southwest of this area have been dug up by mining, and the water content of the mountains is poor. In addition, during the mining process, a large number of tunnels drained and water sources were lost, and the original water balance was broken, resulting in water shortage in the soil layer and vegetation on the hillside, and even the vegetation died in a large area. Coupled with man-made logging and destruction, vegetation and ecological environment have been damaged to varying degrees. In addition, the mountain stream in the mining area soared and plummeted during the flood season, and the water quality was turbid. There are many pits in each mining area, people and sheds are crowded together, and all kinds of domestic wastewater and waste are discharged everywhere. In addition, due to the influence of weathering, some metal sulfides in coal gangue are oxidized and dissolved, which are brought in with precipitation, often causing the contents of bacteria, nitrite and metal elements in these surface water bodies to exceed the standard, and the water bodies are polluted.
Second, the principles and technical measures of green mine construction
The key points of green mine construction in lingbao city are: comprehensive treatment of slag piles, dredging of river courses in mining areas, comprehensive treatment of tailings ponds and comprehensive utilization of solid wastes, restoration of green vegetation in mining areas, prevention and control of geological disasters and land reclamation.
(a) comprehensive management of mine waste residue, river dredging in mining areas and comprehensive management of tailings ponds.
According to the mine geological environment problems caused by excessive accumulation of waste residue in various mines in lingbao city, such as excessive accumulation and blocking of rivers and roads in mining areas, combined with the actual situation of waste residue treatment in various mines at present, on the basis of comprehensive consideration of topography, landforms, geology, engineering economy and technology in mining areas, and referring to the existing treatment experience, it is suggested that waste residue should be used as resources first, and engineering measures such as in-situ solidification treatment and greening should be combined with slope protection and retaining wall construction. The comprehensive treatment of waste residue is divided into two parts: first, the comprehensive treatment of waste residue, including the resource utilization of waste residue (secondary recycling, building stone, brick making, subgrade filling, backfilling goaf, etc.). ), reasonable stacking of waste residue slope, slope protection and retaining wall treatment project, waste residue removal project, river dredging project in mining area, etc. The second is ecological environment restoration, including vegetation restoration projects such as slag slope (slope) re-soil, greening and tree planting. Combined with the actual situation of each mining area, most of the waste rock piles in each mining area are being discharged or will continue to be used due to the limitation of topographic conditions and the deepening of prospecting and mining work in the mining area. Therefore, the waste pile treatment project should be carried out first, and the ecological environment restoration project of the waste pile should be completed after the mines, mining areas and pits are closed and the waste pile is no longer used.
The comprehensive management of tailings reservoir is mainly to prevent dam break, reservoir liquid leakage and tailings dust from damaging the land and environment, and mainly to implement engineering and technical measures such as dam slope protection and reinforcement, improving drainage system of tailings reservoir, covering reservoir surface and greening reservoir area.
(2) Comprehensive utilization of solid waste resources
Adhere to the guiding ideology of "adapting measures to local conditions and actively utilizing", focusing on large-scale utilization. Strengthen the evaluation of resource utilization of slag piles and tailings, scientifically determine their comprehensive utilization ways, secondary recovery of slag piles, building stones, brick making, roadbed paving materials, building engineering filling, goaf backfilling, etc. Tailings are re-selected to recover associated minerals, which can be used as cement additives, tailings brick making and other production building materials and products. This is the main development direction of comprehensive utilization of slag heap and tailings. With the sharp rise in the market price of mineral products, the progress of dressing and smelting technology and the market demand, it is suggested that all mining enterprises should strengthen the research and development of slag heap and tailings resource utilization.
(3) mine greening
Mine greening is an important part of eco-city construction and "Green Mountain and Green Water Project" in lingbao city. The basic principles of mine greening are suitability, comprehensiveness and optimization. Greening in mining areas should be combined with comprehensive management of slag slopes and tailings ponds, land reclamation, species diversity and the development of ecological agriculture. Strengthen the management of mine ecological environment in the region, combine artificial greening with natural greening, give priority to artificial greening, and adopt greening technical measures such as step greening, vertical greening by climbing up and down, and grid spraying greening. Make a special study on the vegetation planning of important mining areas in the region, including the allocation of woodland and forest belt, tree species selection, layout and optimization, so as to make the greening effect of mining areas better. For scenic spots, mining areas and closed stopes near important traffic arteries, according to the requirements of landscape restoration, scientific planning should be carried out, covering soil should be leveled step by step, and grass and trees should be planted.
(4) prevention and control of geological disasters in mines
Underground mining mines should actively promote the technology of not discharging waste rocks in pits and lanes, filling mined-out areas and non-mining areas, reduce the accumulation of waste rocks on the surface and the area of ground subsidence, and level and backfill the subsidence areas and ground fissures in time.
Open-pit mines should make scientific and reasonable mining layout, carry out bench mining in strict accordance with the designed stripping ratio and slope angle, and limit the height of mining face and slope. Measures such as slope shotcrete treatment, waterproof surface construction, cutting and load reduction, slope toe stacking and anti-slide pile support are taken to prevent collapse and landslide disasters.
According to the terrain, landform, geology and other environmental conditions of various mines in the region, the dangerous rock mass and steep slope on the surface of each mining area are investigated and observed, and rock caving, slope setting and avoidance treatment are carried out when necessary to prevent natural collapse and landslide disasters in the mining area. Investigate and monitor the collapse and landslide caused by mining, and timely deal with the hidden dangers that threaten the safety of roads, mine workers and villagers and take evasive measures. Actively carry out comprehensive treatment and comprehensive utilization of a large number of waste residues and tailings piled up in various mines in the area to prevent the occurrence of slag slope collapse, landslide and debris flow disasters caused by instability of slag slope and dam failure of tailings dam.
(5) Land reclamation
The principle of land reclamation is the combination of social ecology and economic development, and the combination of comprehensive environmental improvement and ecological reconstruction; Unified planning before mining, combining mining and reclamation; Land restoration is combined with the adjustment of agriculture and forestry structure; Take effective technical measures to combine prevention and control; Strengthen environmental protection system, theoretical methods and technological innovation, and combine technical economy with policies and regulations.
Technical measures: popularize new technologies such as backfilling mined-out area with waste residue, forbidden mining area, slag heap and tailings resource utilization, effectively and rationally utilize mineral resources and protect land and forest land; Combined with the actual situation, mainly cultivated land, forest land and construction land, scientifically and reasonably determine the use and proportion of reclaimed land; Scientific planning and dynamic reclamation will make the land restoration work gradually move towards a virtuous circle; Pay attention to the systematicness, comprehensiveness, applicability and innovation of land restoration technologies and methods, adjust measures to local conditions and pay attention to actual results.
New solid waste yards, especially tailings ponds, must be selected, evaluated, surveyed, designed, constructed and supervised by professional units with corresponding qualifications in accordance with relevant national standards; The solid waste storage yard being used must be constructed and operated according to the design requirements; The solid waste storage yard that has reached the designed service life or designed storage capacity should be stopped immediately and the library closing procedure should be started. It is forbidden to use it beyond the design capacity. Gangue and waste residue shall be piled up in an orderly manner and covered with soil for greening in time; Regular slag dams and fences must be built in the solid waste storage yard, and masonry slope protection or other solidification measures should be taken to prevent geological disasters such as landslides and mudslides. Clean up the waste rocks and waste residues that occupy the main flood passages such as rivers and valleys, or build flood passages or drainage pipes to ensure the smooth flow of floods and cut off the source conditions of mudslides. For some unstable landslides, unstable slopes and dangerous rocks. , temporarily unable to effectively deal with, timely avoidance, and set up isolation belts and warning signs.
Therefore, it is the future direction and goal of Lingbao Mining to actively build "green mines" and seek the road of circular economy development. In the future work, we should adhere to the following development ideas:
First, protect the environment and take the road of "green mining". In accordance with the requirements of paying equal attention to development and protection, the environmental impact assessment of mine development, geological disaster risk assessment report and soil and water conservation plan report are strictly implemented, the "three simultaneities" system of soil and water conservation and environmental protection facilities construction is adhered to, the construction of "green mines" is promoted, soil erosion and environmental pollution are prevented, the ecological environment of mines is protected, and the development road of "green mines" is environmentally friendly and ecologically protected.
The second is to strengthen governance and achieve discharge standards. Wastes in key mining areas are stored and disposed in a centralized way, pollutants are treated and discharged up to the standard, the total discharge of major pollutants is obviously reduced, environmental pollution accidents and ecological damage incidents are prevented and controlled, the deposit system for mine geological environment restoration is strictly implemented, and plans for mine ecological environment protection and comprehensive management are formulated.
Third, intensive utilization and development of circular economy. Guide mining enterprises to rely on scientific and technological progress and technological innovation, transform traditional mining and dressing technologies and equipment, popularize new technologies and new processes, extend industries and product chains, improve mining recovery rate, mineral processing recovery rate, comprehensive smelting recovery rate and comprehensive utilization rate of associated minerals, promote the transformation of mineral resources development and utilization level from extensive, high consumption and low speed to intensive, economical and efficient, improve the comprehensive utilization level of resources and circular economy value, and turn resource advantages into industrial advantages.