Mining land reclamation is defined in the "Land Reclamation Regulations" as "Land reclamation refers to the adoption of remediation measures for land that has been damaged due to excavation, subsidence, occupation, etc. during the production and construction process. , activities that restore it to an exploitable state." In the early stage of reclamation, the damaged land will be backfilled, leveled, covered with soil and comprehensively renovated and utilized. In the later stage, soil improvement and vegetation planting will be carried out. The types of reclamation should be adapted to local conditions and can be divided into construction land reclamation, agricultural reclamation, forestry reclamation, fishery reclamation and grassland reclamation. The best areas for land reclamation in mines in southwest China include open-pit mines and tailings ponds of large state-owned mines. Many medium and small mines have not yet been included in the reclamation work due to factors such as poor management of tailings discharge and disorderly discharge of waste rock and tailings. schedule.
(1) Reclamation of dumpsites
The reclamation of dumpsites in southwest China is mainly arranged in open-pit mines. For example, Tibet's open-pit gold placer mines have been completely closed down, and pastures are being planted on flat surfaces at the open-pit mining sites. Due to the cold climate and thin air in Tibet, the growth of pastures is extremely slow. Kunyang Phosphate Mine in Yunnan is a large state-owned mine. Parts of the open-pit dumpsite have been leveled and planted with trees and castor trees, which has alleviated soil erosion in the mine.
Sichuan Panzhihua Vanadium Titanium Magnetite Mine is a nationally famous large-scale iron ore mine located in the East District of Panzhihua City. The large open-pit stopes include three stopes: Zhujia Baobao, Lanjia Huoshan and Jianshan, with an area of ??439hm2. In addition to the three stopes on the side of the stope, there are also Zhulan Railway discharge sites in the east. The total area of ??the farm is 410hm2. In recent years, Panzhihua Iron and Steel Group Mining Company has leveled and greened the dump site near the mining site. Through reclamation, vegetables and fruits have been planted, and houses have been built. The older Class I platform at the Julan Railway dump site that is currently in use has also begun to grow a large number of shrubs and weeds. The land reclamation area reached 126.9hm2, and the reclamation rate reached 13.5%.
(2) Reclamation of Tailings Ponds
1. Reclamation Measures of Niuba Waste Tailings Pond in Gejiu Tin Mine
Reclamation of tailings ponds in southwest China is relatively Good mines are large state-owned mines. For example, the Niubahuang tailings reservoir of Gejiu Tin Mine in Yunnan Province is located 2km south of Gejiu City, spreading in a northeast-southwest direction, covering an area of ??about 5.22km2, and has stored 3150×104m3 of tailings. It was closed on May 22, 1998. Gejiu Tin Company has leveled the tailings pond, covered it with soil 0.5m thick, and has planted corn, increasing the area of ??cultivated land for the local area.
2. Reclamation measures for the Majiatian tailings pond of Panzhihua vanadium-titanium magnetite mine
The Majiatian tailings pond of Panzhihua vanadium-titanium magnetite mine in Sichuan was first built in December 1966 , completed and put into production in 1970, covering an area of ??17.92km2. The tailings pond is generally a large tailings pond, but the interior is composed of several cascades of small tailings ponds along the ravine from bottom to top. The tailings ponds piled up in the early stage have been gradually reclaimed, leveled, and covered with sandy clay about 0.5m thick. They were first planted with grafted trees. After testing, the results were not good and the survival rate was low. After several years of screening and practice, it was found that planting bean sprouts, oil rice seeds and sisal had a high survival rate and good growth. At present, relevant management departments are summarizing experience and expanding the scale of planting.
3. Reclamation measures for the tailings pond of Lala Copper Mine
Sichuan Lala Copper Mine is located 80km south of Huili County. It is a large mine located on the east bank of the Jinsha River, covering an area of Area 4km2. Since 1985, the mine has begun reclamation and management of some closed open-pit stopes, dumpsites, and tailings ponds. For example, the No. 1 tailings pond was closed in 1985 and covered with soil and greening. The soil thickness was 30 to 50 cm. No trace of tailings can be seen on the surface. The mine also transformed the southern section of the tailings pond into a sports ground for the children's school. Includes football field and running track. Eucalyptus trees are planted around the area with a diameter of 20-30cm. Vegetation such as sisal and shrubs grows thickly on the tailings dam.