Several common environmental problems in mine projects

With the development of the national economy and the improvement of people's living standards, the demand for mineral resources in the society has obviously increased, and the corresponding development of mines has also increased significantly. The environmental protection in mines has also received more and more attention. The state's environmental requirements for mining projects are increasingly standardized and strict, and a series of norms and standards have been promulgated. Due to the lack of attention to current environmental protection regulations and policies, some small and medium-sized mines have unreasonable site selection for tailings ponds and waste quarries. The scale and service life of mines are not in line with national industrial policies and production technologies fail to meet clean production standards. Many environmental problems have caused the project to fail to pass the EIA review and ultimately cannot be implemented. This paper analyzes and summarizes several common environmental problems in mine projects, and provides reference for the environmental protection design of mines.

Second, the location of the tailings pond and waste rock yard

It refers tailings Taniguchi damming or enclosed spaces for the storage of ore for metal and nonmetal mine tailings discharged after sorting configuration. The tailings pond is the key and key to the environmental assessment of the mine project. The site selection must be reasonable, the storage capacity meets the service life requirements, and the tailings dam complies with the safety technical regulations.

(1) The selection of the tailings pond site should comply with the following principles:

1. It should not be located in industrial and mining enterprises, large water sources, aquatic production bases and upstream of large residential areas.

2. It should not be located upstream of the national and provincial key protected historical sites.

3. Avoid areas with complex geological structures and serious geological phenomena.

4. Do not occupy or occupy less farmland, and do not move or move less villages.

5, should not be located in the mining bed with mining quality.

6, the catchment area is small, there is enough storage capacity and the initial and final length of the library.

7. The dam construction project is small and the production management is convenient.

8. The tailings have a short conveying distance and can be self-flowing or with a small lift.

(2) In addition to meeting the above principles, the author summarizes several examples of mine environmental assessment and relevant environmental regulations of the State Environmental Protection Administration, and considers that the location of tailings waste and waste rock sites should focus on:

1. According to the "General Industrial Solid Waste Storage and Disposal Site Pollution Control Standards" (GB18599-2001), the site should be selected in the industrial zone and the residential concentration zone to dominate the wind downwind side, and the site boundary is 500m away from the residential concentration zone. This is the focus of the EIA review. The design of many mine projects did not consider this environmental protection requirement. The problem of the location of the tailings pond or waste rock yard and the distance between the village and the residential area was less than 500m, resulting in the site being selected by the EIA approval department. Negate or cause a large number of residents to relocate.

2, should avoid the fault, fault fracture zone, cave area, and natural landslide or debris flow affected zone.

3. Do not occupy basic farmland. The "Regulations on the Protection of Basic Farmland" and the "Notice on Further Adopting Measures to Implement Strict Protection of Cultivated Land System" stipulates in the Ministry of Land and Resources that non-agricultural construction outside the state's key construction projects is not allowed to occupy basic farmland. Therefore, in the selection of the tailings pond and waste rock yard, the basic farmland should not be occupied. If the cultivated land is approved and occupied, it is necessary to reclaim the cultivated land with the same quantity and quality of cultivated land, and no conditions for reclamation or reclamation. If the cultivated land does not meet the requirements, the cultivated land reclamation fee shall be paid according to law, and the special funds shall be used for the opening of new cultivated land.

4, in line with the overall planning of the construction business, the useful life of the tailings beneficiation plant production, working hours fit; small concentrator should not be less than five years, large and medium-sized concentrator should not be less than 10 years. At the same time, the state encourages the promotion of the use of overlying strata, using tailings, waste rock to fill the goaf and other technologies to reduce the overburden collapse in the goaf.

Third, the analysis of the conformity with industrial policy

The development of mineral resources shall comply with the requirements of the national industrial film policy. The site selection and layout shall conform to the regional development plan of the locality. The compliance of the project with the national industrial policy is one of the main contents of the EIA approval. Projects that do not conform to the national industrial policy cannot be approved by the EIA.

(1) The author summarized the restricted mine projects according to the National Industrial Catalogue (2005):

1, single well well below the size of the following type of coal mine projects: Shanxi, Shaanxi, Inner Mongolia, 300,000 t / a; Xinjiang, Gansu, Ningxia, Qinghai, Beijing, Hebei, Northeast and East China 150,000 t / a; the southwest and 90,000 t/a in Central South China; 30,000 t/a in extremely thin coal seams;

2. Coal mine projects using non-mechanized mining processes;

3. The designed coal resource recovery rate does not meet the coal mine project required by the state;

4. The overall planning of the mining area has not been approved by the national or provincial (regional, municipal) coal industry management department;

5. Tungsten, molybdenum , tin , antimony and rare earth mining projects (except for renovation projects);

6. An independent gold ore dressing project with no ore supporting mining system for processing ore below 100t;

7. Disposal of independent heap leaching projects with ore below 50,000 t/a (excluding the Qinghai-Tibet Plateau);

8. Mining and selecting projects below 50t of rock gold ore;

9. Handling gold mining projects with a sand gold ore of less than 200,000 m ³ /a;

10. Mining gold projects in forest areas, farmland, and rivers.

(2) The project of eliminating mines is summarized as follows:

1. Coal mines that have not been constructed in accordance with the approved mine area plan and well type;

2. Coal mines without mining licenses, safety production licenses, business licenses, mine qualification certificates, and coal production licenses;

3. All kinds of small coal mines within the scope of state-owned coal mining areas (the scope of state-owned coal mining registration confirmation);

4. Mines with a single well type below 30,000 t/a (except for extremely thin coal seams);

5. There is no sulfur reduction measure, and there is no high-sulfur coal (sulphur content higher than 3%) that meets the standards for the production of mines;

6. It is not possible to produce mines in high-ash coal (ash content higher than 40%) used locally;

7. Except for the approval of the competent department of the State Council, the mining and selection of specific minerals for which protective mining is carried out by countries such as tungsten, tin, antimony and ionic rare earths without mining licenses;

8. Small pool dip and small heap leaching process;

9. Without the approval of the competent department of the State Council, there is no mining and mining project for mining gold minerals approval and mining license.

In addition, the “Technical Policy for Mine Ecological Environment Protection and Pollution Prevention and Control” stipulates that nature reserves (core areas, buffer zones), scenic spots, forest parks, drinking water source protection areas, important lakes, cultural relics and historic sites designated in accordance with the law are prohibited. location in the area of mining, geological remains protected areas, basic farmland protection zones; prohibited in open pit mining railways intuitive visual range, State Road, dart sides. It is forbidden to open mining resources in geological disaster danger zones; it is forbidden to build new mineral resources development projects that have devastating effects on the ecological environment and make them irreusable.

Regarding the service life of the mine, in order to promote environmental protection and ecological restoration, the general requirement should not be less than 5 years. The Ministry of Land and Resources "Notice on Adjusting the Scale Standards for the Production and Construction of Some Mineral Mines" (Guo Tu Zi Fa [2004] No. 208) has stipulated the construction scale of the mine. The minimum production and construction scale of the mine is shown in Table 1.

Table 1 List of minimum construction scale of mine production 10,000 t/a

The Integrated Wastewater Discharge Standard stipulates the water reuse rate of the beneficiation project, as shown in Table 2.

Table 2 The highest allowable displacement in the mineral processing industry

Fourth, clean production

The clean production standards recommended by the State Environmental Protection Administration are divided into three levels, one represents the advanced level of international clean production, the second represents the advanced level of domestic clean production, and the third represents the basic level of domestic clean production. When all the indicators of a construction project meet the first or second level standards, from the perspective of cleaner production, the project is a good project and acceptable. When all the indicators of a construction recommendation reach the third-level standard, it indicates that the project is generally done in terms of process, equipment selection, resource and energy utilization, product design and use, waste generation in the production process, waste recycling and environmental management. As a new construction project, it is necessary to make major adjustments and improvements in design and other aspects so that it can reach the domestic advanced level. When all the indicators of a project do not meet the third-level standard, from the perspective of cleaner production, the project cannot be accepted.

The State Environmental Protection Administration has issued clean production standards for some industries. The author lists the technical requirements for clean production in the iron ore mining industry, as shown in Table 3.

Table 3 Technical requirements for clean production in iron ore mining industry (mineralization)

In order to achieve energy conservation and emission reduction, mine development must adopt clean production technology. Some cleaner production technologies have proven to have significant economic and environmental benefits through production practices. The State Environmental Protection Administration requires all regions and relevant departments to promote the application in the industry or similar production equipment in combination with the actual situation. The author collects and cleans the clean production techniques of the mine project, as shown in Table 4.

Table 4 Clean production technology of mine projects

V. Conclusion

The relevant regulations and requirements of the state for the development of mineral resources are constantly updated and adjusted. Therefore, mine designers and environmental evaluators should pay close attention to and understand national policies and regulations, rational design, correct evaluation, ensure that projects meet environmental protection requirements, and minimize the damage to the environment while mineral development continues to develop.