What are the negative effects of mining and aggregate production on the environment? How can mining and quarrying reduce the environmental impact? This article shares 6 ways to make mines and quarries more sustainable.
Aggregate production and domestic wastewater discharge mainly include:
Production wastewater discharge
Due to the needs of stone washing and dust removal, the amount of wastewater discharged is large, and the content of suspended solids such as stone powder and fine sand in the wastewater is large.
Oil pollution discharge
The construction machinery of the artificial sand and gravel system will pollute the environment due to leakage and spilled oil during operation and maintenance.
Domestic wastewater discharge
The sand and gravel system and the concrete system take up about 1/4 of the labor force of the whole project. It is responsible for about 90% of the transportation volume of the whole project. There are many construction site canteens, hospitals, etc., and the discharge of domestic sewage is considerable.
The wastewater of the project is not discharged outside, reducing the impact on the surrounding environment.
The production of gravel and sand will generate a large amount of dust, which will endanger the health of operators and damage the production of agriculture, forestry and animal husbandry. Dust falling into the mechanical equipment will cause wear and oil pollution, affect the life of the equipment or damage the insulation and cause accidents.
The main sources of dust in the construction area are:
Crushing, screening and transportation of aggregates.
A large number of transportation, excavation and loading vehicles in the construction area raise dust during work.
Most artificial sand and gravel systems use blasting to mine raw rock. During the explosion of explosives, gun smoke is generated, which contains a large amount of dust and a small amount of toxic gases such as CO, NO2, S02, H2S, and endangers the health of on-site operators.
Fuel combustion not only produces a large amount of CO2 waste gas, but also produces a large amount of fly dust.
The vibrating screen adopts semi-enclosed operation and is equipped with spray sprinklers.
The dust generated by the crusher and sand making machine is processed by a bag filter.
Before blasting, spray dust suppression water on the blasting area to make the blasting area sufficiently moist. Before using the loader to transfer sand and gravel, water should be sprayed to suppress dust and increase the humidity of the ore. During the shoveling process, control the shoveling height to avoid the hopper from being too high. The stone storage yard is sprayed with water regularly to reduce the amount of loading, unloading, transportation and wind dust.
Increase the frequency of cleaning and watering in the factory area and transportation roads. During transportation, some stones will be spilled on the road. Clean the road in time and spray water regularly to keep the road clean, increase the frequency of road cleaning and watering, and clean the road once a day and spray water 3~5 times to reduce the vehicle transportation process. The generation of dust in the middle.
Try to choose a time period with better atmospheric diffusion conditions for blasting operations.
The noise generated by the artificial sand and gravel system mainly includes:
Fixed and continuous mechanical noise. For example, the noise of the belt conveyor can reach 105dB or more during operation, and the aggregate screening machine, rod mill, crusher, etc. can reach 115dB, which are of high frequency nature.
Mobile and continuous mechanical noise. Such as large transportation vehicles, bulldozers, loaders, excavators, high-frequency vibrators, drilling rigs, etc. The maximum noise level of these mechanical equipment is about 90-100dB.
Most operating points of the artificial sand and gravel system have serious noise pollution, which endangers the health of construction workers and surrounding residents.
In order to further reduce the impact on the surrounding acoustic environment, the following measures can be taken:
Night production is strictly prohibited.
Strengthen equipment maintenance and repair work.
Green coverage in the site area can be considered to reduce the impact of project noise on the surrounding area.
During the mining process, water and soil conservation facilities and vegetation will be destroyed, which will damage the ecological environment of the area. At the same time, the soil stability and soil structure under natural conditions will be destroyed. The soil becomes loose and the soil erodibility increases, which will inevitably lead to water and soil. Increase in churn.
The main water and soil erosion hazards that the project may cause are:
Exacerbate soil erosion and reduce soil and water conservation functions.
Cause local landslides and collapses, affecting safety.
Affect the water quality of nearby surface water bodies.
The main characteristics and hazards of soil erosion in open-pit quarries are large area of damage, large degree of erosion, and difficulty in restoration.
It is recommended that mining enterprises implement the following soil erosion protection measures to reduce environmental impact:
Do a good job in the prevention of soil erosion, minimize the man-made soil erosion caused by the mining process, and prevent the damage to the water and soil resources outside the scope of the project land acquisition.
All the earth and stone excavated in the project are used in the project, and the earth and stone excavation, filling, transportation and other construction adopt blocking measures to reduce the intensity of soil erosion and reduce the damage to the ground around the construction site and on both sides of the road.
The layout of the temporary soil yard is based on consideration of safety and feasibility, minimizes the land occupation, less damages to the existing water and soil conservation facilities, and at the same time does a good job of protection. After the earth is used, the site is leveled.
During the production and operation period, the ore is mined without rolling slopes, and all the silt carried by the drainage of the mining area is settled. Except for the buildings occupied by the exposed surfaces of the mining area, all the exposed surfaces of the mining area are restored or reclaimed to reduce soil erosion and leave no landslides. Hidden hazards such as collapse and mudslides.
To achieve the integration of water and soil erosion management and landscape protection, through greening and beautifying construction, the environmental quality will be improved, and water and soil erosion must be prevented from causing harm to other units and individuals.
Conduct water and soil conservation monitoring in key monitoring areas such as exposed surfaces of excavation, temporary soil dumps, and nearby drainage outlets. The monitoring content mainly includes water and soil erosion influencing factors, water and soil loss, water and soil erosion disasters, and water and soil conservation facilities. Water and soil conservation facilities must be designed, constructed and put into operation at the same time as the main project.
The solid waste generated during the mining period is mainly waste soil separated from soil and rock after blasting, sedimentation tank sludge, and domestic garbage generated by employees.
It is necessary to establish a waste slag yard for classified storage to avoid the loss of control of the slope of the slag yard and the loss of waste slag, block the river and damage the ecological environment.
After the blasting, the waste soil separated from the soil and rock is transported to the soil dump site and temporarily stored in the soil dump site. The topsoil and the waste soil and rock are piled separately for later green cover and site leveling.
The sludge from the sedimentation tank is used for plant greening and backfilling.
The sanitation department will dispose of the domestic garbage after being collected.
Rehabilitating mining sites
After the mine service period expires, the industrial site and various facilities will be demolished, and the dust, noise, waste water and other pollution generated during the mining period will be eliminated. However, after the mine is decommissioned, a large area of mining waste land will be caused, mainly including the stripping of the topsoil layer and mining The waste rock accumulation site formed by the accumulation of rock fragments, etc., the mining waste land left after the ore body is mined, the slag waste land formed by the accumulation of the slag generated by the mined ore, as well as the mining operation surface, mechanical facilities, and mining areas Auxiliary buildings and road traffic, etc. occupy first and then abandoned land, etc.
Do a good job of stripping and stacking the topsoil of mine construction projects, and reserve enough cultivated soil for later restoration projects.
Do a good job in stope drainage. The mine is open-pit mining, which has caused damage to the vegetation on the surface and loosening of the soil, so water and soil conservation should be done well.
Do a good job in removing dangerous rocks and pumice from the high and steep slopes of the open pit. The blasting operation has caused a certain scale of dangerous rock and pumice on the local working face of the stope, which should be removed to eliminate hidden dangers.
Carry out land reclamation work. The objects of reclamation are mound yards, stope platforms, structures, crushing processing sites and mine roads, except for a small amount of reserved for forestry management and protection, the rest are all reclaimed, and the type of reclaimed land is forest land.
Carry out vegetation reconstruction work. Plant trees, lawns and vines suitable for growth in the mining area on the reclaimed forest land to ensure a survival rate of greater than 85%; cover the stope with soil on the platform of the stope, plant vines, and use the characteristics of climbing and hanging vines to cover the stope High and steep slope. Dumping dams, intercepting ditches, slag dams and other edges are suitable for grass and trees, and trees are suitable for trees. For vegetation reconstruction, select drought-tolerant, barren-tolerant, fast-growing, strong soil-fixing ability, strong climbing ability, and evergreen varieties in all seasons, such as masson pine, ivy, creeper, etc.
Carry out mine geological environment monitoring work. Establish a certain number of monitoring points. Monitor the occupation and destruction of land and vegetation resources in mining areas, and monitor soil erosion in mining areas.