Construct green mines and promote circular economy

Lingbao City is located on the western border of Henan Province, at the junction of Henan, Shaanxi and Shanxi provinces, and is affiliated with Sanmenxia City. The Xiaoqinling Mountains extend into Lingbao City from west to east, lying in the southwest of Lingbao City. The mountains are tall and steep, with strong cutting. The main peak, Laoya Chanao, is 2,413.8 meters above sea level. The Xiaoqinling mining area covers an area of ??1,049 square kilometers and is the second largest rock gold base in the country. Its annual gold output ranks second among counties (cities) in the country. As human engineering activities continue to increase, mining has increasingly damaged the natural environment. Due to mining and the disorderly accumulation of slag, debris flow disasters occur frequently in mining areas. The natural environment in the area has been severely damaged, and geological disasters seriously threaten the safety of national property and people's lives. As an important major gold producing area in the country, especially in the context of developing a mining circular economy, it plays an important role in strengthening the restoration and management of the geological environment of mines, actively building green mines, and promoting the sustained, healthy and stable development of the mining economy.

1. Current status of mining geological environment and major environmental issues

(1) Damage and occupation of land resources

There are many pit entrances in various mining areas in Lingbao City. They are distributed along various large and small valleys and valleys. There are many people in the mining area and there are clusters of work sheds. Mining waste residues are mostly piled along slopes or transported over short distances and piled up in large quantities near pit entrances. According to incomplete statistics, the accumulated waste residue storage volume in each mine reaches 25.808 million tons, of which gold mine waste storage volume reaches 18.849 million tons, accounting for 73.0%. There are 31 tailings ponds in each gold mine and pyrite mine, with 15.7102 million tons of existing tailings slag. During many years of mining production, large amounts of slag accumulated in valleys and rivers, which not only occupied and destroyed a large amount of land, but also severely damaged a large amount of forestry resources, causing great damage to the mining area and its surrounding ecological environment. A conservative estimate is that the area of ??land affected and occupied by mining is about 45,000 acres. Currently, each tailings pond occupies nearly 7,500 acres of land; the area affected by dust hazards is approximately 7.68 million square meters.

(2) Ground subsidence, ground fissures, collapses, and landslides in the goaf area

Some mining areas within the territory have steep terrain, numerous cliffs, developed fractures, relatively broken rock mass, and are affected by gravity. Natural cliff collapse occurs from time to time. For example, a huge cliff collapse occurred in the Chuchagou area of ??Zaoxiang Valley. The boulders fell instantly and the ground shook. Mine workers and work sheds gather in the ravine, and collapse will cause casualties and property losses. In addition, the destruction of natural slopes by mining, road construction, etc. in various mining areas, and the artificial cliffs formed by slope cutting are the main places where mine collapses occur. For example, the collapse of Sifangou in 1996 destroyed a field survey base of the Golden Ninth Detachment of the Armed Police, resulting in the death of two team members.

Four mining-induced landslides have been discovered, posing a greater threat to the lives and property of the mining area itself and surrounding residents. For example, in the Dahuyukou landslide area of ??Yangping Town, there are two landslides here, namely the Xishan landslide and the Dongshan landslide. The Dongshan landslide occurred on November 1, 1987, with a volume of 40×104 cubic meters, causing 3 deaths and direct economic losses. Reaching more than 7 million yuan. Ground fissures caused by mining are mostly seen near the collapse of slag piles and landslides caused by ground collapse edges, trailing edges of landslides, and slag slope instability in mining areas, endangering the safety of nearby residential houses, work sheds, roads, and other property.

(3) Slag slope instability, tailings dam collapse, debris flow

Slag produced from underground tunnel mining in various mining areas in Lingbao City for many years is accumulated along the slopes in various valleys In (valleys), many mining areas have steep terrain and narrow ravines. Over time, the slag slopes have been stacked too high and the slag piles are too large to varying degrees. This is especially serious in local valleys and mining areas.

Most of the tailings ponds of various mines in the territory are located in valleys or loess gullies. Most of the areas around the processing plant and the tailings ponds are farmland and residential areas. They not only occupy a large amount of land, but also cause high pollution due to the accumulation of tailings. As a result, the land in the reservoir area continues to decrease, and the ecological environment near the reservoir area continues to deteriorate. The tailings slag often forms dust and sand during the dry season, affecting surrounding people and causing harm to the land near the reservoir area. At the same time, the existence of tailings ponds has posed a major hidden danger of dam failure, posing a threat to the lives and property of downstream residents.

There are 22 debris flow ditches in the area, and 9 debris flow ditches with moderate susceptibility. The development characteristics of debris flow are: sudden outbreak, fast movement, and high energy. It is very destructive and often causes great harm to people's lives and property. The degree of harm is generally major or extra-large.

In July 1998, a heavy rainstorm occurred at the Wenyu Gold Mine in the Wenyu Valley and a debris flow disaster occurred, destroying 16 kilometers of roads in the mining area, more than 10 bridges and culverts, and several large mechanical equipment such as transformers and air compressors. The power supply and communications in the mining area were interrupted. The mining area stopped production, causing economic losses of 4.73 million yuan.

(4) Water balance destruction

Due to the production and development of many gold mines in Lingbao City over the years, most of the mountains in the southwest of the area have been devastated by mining. The water richness of the mountain is inherently poor. Coupled with the large amount of tunnel drainage and water source loss during mining, the original water balance is broken, causing the soil layer and vegetation on the hillside to be short of water, or even causing large areas of vegetation to die. In addition, artificial felling, Destruction, vegetation and ecological environment have been damaged to varying degrees. In addition, mountain streams in the mining area surge and plummet during the flood season, making the water turbid. Mining areas are densely populated with people and work sheds, and various domestic wastewaters are discharged everywhere. Coupled with the influence of weathering, some metal sulfides in the waste rocks in the fields are oxidized and dissolved, and brought with precipitation, resulting in the formation of surface water bacteria, nitrite The content of salt and metal elements often exceeds the limit, and the water body is polluted.

II. Principles and technical measures for green mine construction

The focus of green mine construction in Lingbao City is: comprehensive improvement of slag piles, cleaning and dredging of rivers in mining areas, comprehensive management of tailings ponds and solid Comprehensive utilization of waste resources, restoration of green vegetation in mining areas, prevention and control of geological disasters, land reclamation, etc.

(1) Comprehensive management of mining waste slag, cleaning and dredging of rivers in mining areas, and comprehensive management of tailings ponds

According to the excessive accumulation of waste slag in various mining areas in Lingbao City, the piles are too high , blocked rivers, blocked roads in mining areas and other mining geological environmental problems, combined with the actual situation of waste residue treatment in various mines, and based on comprehensive consideration of the topography, geomorphology, geology, engineering economic and technical conditions of the mining area, and drawing on existing management experience, it is recommended that first Consider the resource utilization of waste residue, and combine the methods of building slope protection and retaining walls to implement in-situ solidification treatment, greening and other engineering measures for the waste residue. The comprehensive management of waste residues is divided into two parts: First, the comprehensive management of waste residues, including the utilization of waste resources (secondary recycling, building stones, brick making, roadbed paving materials, backfilling of goafs, etc.), implementation of waste slopes Reasonable stacking, slope protection, retaining wall management projects, waste residue removal projects, mining area river cleaning and dredging projects, etc.; second, ecological environment restoration, including residue slope (slope) soil restoration, greening, tree planting and other vegetation restoration projects. Based on the actual situation of each mining area, due to the restrictions of terrain conditions and the in-depth prospecting and mining work in the mining area, most of the waste slag piles in each mining area are being discharged or will continue to be used. Therefore, waste slag treatment projects are first carried out to improve the ecological environment of the waste slag piles. The restoration project will be implemented after the mine, mining area, and pit mouth are closed and the slag pile is no longer in use.

Comprehensive management of tailings ponds is mainly to prevent tailings pond collapse, leakage of pond liquid, and tailings dust from causing damage to the land and environment. It mainly implements slope protection to strengthen the dam body, improves the tailing pond drainage system, and improves the tailings pond drainage system. Engineering and technical measures such as surface covering with soil and greening of the 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 bulk utilization. Strengthen the evaluation of resource utilization of slag heaps and tailings, scientifically determine their comprehensive utilization methods, secondary recycling of slag heaps, building stones, brick making, roadbed paving materials, filling of construction projects, backfilling goafs, etc.; tailings recycling Select and recycle associated minerals for use as cement additives, tailing brick making and other production of building materials and products. These are the main development directions for the comprehensive utilization of slag heaps and tailings. With the substantial increase in market prices of mineral products and the advancement of smelting technology and market needs, it is recommended that mining enterprises should strengthen the resource utilization of slag heaps and tailings. research and development work.

(3) Mine greening

Mine greening is an important part of Lingbao City’s ecological city construction and implementation of the “Green Mountains and Green Waters Project”. The basic principles of mine greening are suitability, comprehensiveness and optimization. Greening of mining areas should be tailored to local conditions and mines, and should be organically combined with comprehensive management of slag slopes and tailings ponds, land reclamation, species diversification and the development of ecological agriculture. Strengthen the management of the ecological environment of various mines in the region, and use a combination of artificial regreening and natural regreening on slopes. Artificial regreening is the main method, and steps are adopted to green the slopes, climb up and hang down vertical greening, and grid spray greening. Regreening technical measures. Conduct a special study on the vegetation planning of important mining areas in the region, which should include issues such as the allocation of forest lands and forest belts in mining areas, tree species selection, layout, and optimization, so as to achieve better greening effects in mining areas.

For mining areas and closed stopes near scenic spots and important traffic arteries, scientific planning shall be carried out according to the landscape restoration requirements, and soil shall be leveled and covered in steps, and grass and trees shall be planted.

(4) Prevention and Control of Geological Disasters in Mines

Underground mining mines should actively promote technologies such as not discharging waste rocks in tunnels and tunnels, filling goaf areas and non-mining areas, and reduce the amount of waste piled on the surface. According to the ground subsidence area, the subsidence area and ground fissures should be leveled and backfilled in a timely manner.

The open-pit mine shall formulate a scientific and reasonable mining layout, carry out stepped mining in strict accordance with the designed stripping ratio and slope angle, and limit the mining surface and slope height. Measures such as shotcrete treatment on slopes, construction of waterproof surfaces, load reduction by cutting, pile loading at slope toes, and anti-slide pile support are adopted for dangerous sections of open pits to prevent collapse and landslide disasters.

Based on the topography, geomorphology, geology and other environmental conditions of each mine in the area, investigate and observe the dangerous rock masses and steep slopes on the surface of each mining area, and carry out rock placement, grading and avoidance treatment when necessary. , to prevent natural collapse and landslide disasters in mining areas. Investigate and monitor collapses and landslides caused by mining, conduct timely engineering management and take avoidance measures for hidden dangers that threaten the lives and property of roads, mine workers, and village residents. Actively carry out comprehensive management and comprehensive utilization of resources for the large amounts of waste residue and tailings stored in various mines in the area to prevent the occurrence of slope collapse, landslides and debris flow disasters caused by slope instability and tailings dam failure.

(5) Land Reclamation

The principles of land reclamation are the combination of social ecology and economic development, the combination of comprehensive environmental improvement and ecological reconstruction; unified pre-mining planning, mining and rehabilitation Combining land reclamation with land reclamation; combining land restoration with structural adjustment of agriculture and forestry; taking effective technological measures to combine governance with prevention; strengthening environmental protection systems, theoretical methods and technological innovation, and integrating technology and economy with policies and regulations.

Technical measures: Promote new technologies such as waste slag backfilling goafs and non-mining areas, resource utilization of slag piles and tailings, effectively and rationally utilize mineral resources and protect land and forestland; combine with actual conditions, use cultivated land , forest land, and construction land, determine scientific and reasonable land uses and proportions for reclamation; scientific planning, dynamic reclamation, so that land restoration work gradually moves into a virtuous cycle; pay attention to the systematicness, comprehensiveness, suitability and suitability of land restoration technical methods Innovative, adapt to local conditions, and focus on practical results.

New solid waste dumps, especially the construction of tailings ponds, must be sited, assessed, surveyed, designed, constructed and supervised by professional units with corresponding qualifications in accordance with relevant national regulations; the solid waste in use must be The storage yard must be constructed and operated in accordance with the design requirements; solid waste storage yards that have reached the designed service life or designed storage capacity should be decommissioned immediately, the storage closure process should be initiated, and use beyond the design capacity is strictly prohibited. Waste rock and waste residues should be piled up in an orderly manner and covered with soil and greening in a timely manner; solid waste dump sites must build formal slag dams and slag retaining walls, and use grouting and stone protection on the slopes or other solidification measures to prevent geological disasters such as landslides and debris flows. . Clean up the waste rocks and residues occupying the main flood channels such as rivers and valleys or build flood channels or drainage pipes to ensure the smooth passage of floods and cut off the source conditions for debris flow formation. For some unstable landslides, unstable slopes, dangerous rock masses, etc. that cannot be effectively controlled for the time being, avoid them in a timely manner and set up isolation zones and warning signs.

Therefore, actively building "green mines" and seeking a path to circular economy development are the future directions and goals of Lingbao Mining. In future work, the following development ideas should be adhered to:

< p>First, protect the environment and take the road of "green mining". In accordance with the requirements of who develops, who protects, who destroys, who governs, and who pays equal attention to development and protection, strictly implement the environmental impact assessment of mining development, geological disaster risk assessment report, and soil and water conservation plan report, and adhere to the "Three Simultaneities" in the construction of water and soil conservation and environmental protection facilities. "system, promote the construction of "green mines", prevent soil erosion and environmental pollution, protect the ecological environment of mines, and follow the development path of "green mining" that is environmentally friendly and ecologically protective.

The second is to strengthen governance and achieve emission standards. Waste in key mining areas is stored and disposed of in a centralized manner, pollutants are centrally managed and discharged in compliance with standards, the total discharge of major pollutants is significantly reduced, environmental pollution accidents and ecological damage events are prevented and controlled, the deposit system for the restoration of the geological environment of mines is strictly implemented, and the mines are formulated Ecological environment protection and comprehensive management plan.

The third is intensive utilization and development of circular economy.

Guide mining enterprises to rely on scientific and technological progress and technological innovation to transform traditional mining and dressing processes and equipment, promote new technologies and processes, extend industry and product chains, and improve mineral resource mining recovery rates, mineral processing recovery rates, smelting comprehensive recovery rates and *** The comprehensive utilization rate of associated minerals promotes the transformation of the development and utilization level of mineral resources from extensive, high consumption, and low speed to intensive, economical, and efficient, improves the comprehensive utilization level of resources and the value of circular economy, and transforms resource advantages into industrial advantages and economic advantages.