Southwest China has the largest number of non-metallic mining enterprises, with 11,301, accounting for 53.6% of the total number of mining enterprises. Among them, 3,918 are in Yunnan, 3,260 in Sichuan, 2,364 in Guizhou, 156 in Tibet and 1,603 in Chongqing. Important mining enterprises include Shifang Phosphate Mine, Mabian Phosphate Mine, Baoxing Marble Mine, Ya'an Granite Mine, Asbestos Granite Mine, Tianquan Sulfurous Iron Ore Mine, Jiangyou Sulfurous Iron Ore Mine, Pengxian Serpentine Mine, Dukou Fritter Tuff Mine, Ebian Glass Sand Mine, Jiangyou Water Mud Limestone Mine, Emei Water Mud Limestone Mine in Sichuan, Fuyuan Sulfurous Iron Ore Mine, Kunyang Phosphate Mine in Yunnan, Sanquanhe Sulfurous Iron Ore Mine, Gongli Crystal Mine, Kaili Glass Sand Mine, Shui Cheng Fused Limestone Mine, Kaiyang Phosphorus Mine, Chongqing Gele Mountain Fused Limestone Mine, and Tibet Zabuye Borax Mine. These mining enterprises are generally located in areas with relatively convenient transportation, such as highways, railroad lines, and riverbanks. Among them, chemical non-metallic mines such as sulfur and phosphorus mines are more prominent in terms of environmental pollution and soil erosion; non-metallic building materials mines such as granite, marble, cement chert, shale, sandstone, as well as ceramic clay and other mines, the amount of slag is large, occupying, destroying land resources, destroying the landscape along the transportation routes, as well as the formation of landslides, mudslides, and other environmental problems are prominent.
(A) non-metallic mines on the destruction of resources
1. non-metallic mines on the impact and destruction of landscape
Large-scale non-metallic mining activities, especially open-pit mines, as well as mining activities induced by the geologic hazards, often make the mining area topography, landforms, landscapes suffered damage to the deterioration of the regional ecological environment. Mining activities along main highways and around rivers and lakes have a particularly prominent impact on topography and geomorphic landscape. Most of the building materials and other non-metallic mines in the southwest region are located along the highway, and the mountain slopes in the mining area form a piece of "white stubble mountain", which seriously affects the landscape along the highway, and then affects the image of the southwest tourism region. Such as Yunnan Dianchi basin distribution of Kunyang phosphate mine, Jinning phosphate mine and other size of dozens of phosphorus mine and dozens of quarries, sand quarries, mining activities not only damage the vegetation, the formation of a large area of the "bald mountain", and a considerable portion of the mining site is built in the slope 35 ° or more steep slopes, collapse, landslides, soil erosion is serious, so Dianchi The ecological environment of Dianchi is seriously affected. Dianchi basin forest vegetation from 25.1% in 1975 fell to 21.2% in 1988, Dianchi average annual siltation amount of 33.1 × 104m3, resulting in the lake bottom elevation, the lake surface shrinkage, so that the "Pearl of the Plateau" eclipsed. In addition to the above, Yunnan Qubei Puzhehei Scenic Area had several quarries in the second level of protection, so that the landscape of the scenic area has been significantly affected; Wenshan County Laojunshan Nature Reserve in the past, there are about 10 large and small mining enterprises, including arsenic factory there are three, causing great damage to the forest vegetation; Dali Cangshan elevation of more than 2,500m in the past there were a number of quarries to extract marble, but also the formation of a piece of "white stubble mountains", the "white stubble mountains". "white stubble mountain", mining waste rock also exacerbated the Cangshan mountain creeks and gorges of the frequency of outbreaks of debris flow, exacerbated the Erhai siltation.
Chongqing Jialing River Guanyin Gorge along the quarry is located in Beibei District. The area has beautiful geological landscapes and typical geological profiles. In recent decades, on both sides of the Guanyin Gorge has built Jialing Cement Plant, Jiangbei County Cement Plant, Fuhuang Cement Plant, mainly quarrying Jialing River on both sides of the Lower Triassic Unified Jialingjiang Formation and Feixianguan Formation limestone quarry. At present, three large-scale mining areas are formed on both sides of the Jialing River, covering an area of 0.66×104m2, 0.6×104m2, 0.84×104m2, with a volume of 105.6×104m3, 42×104m3, and 67.2×104m3, respectively (Ren Yurong et al., 2006). Large-scale limestone mining has exposed the bedrock in the mining area without vegetation cover, and the former green hills have become today's barren and bald hills, seriously damaging the natural geological landscape along Guanyin Gorge (Photo 3-13). At the same time, in the mining area to form 70 ~ 160m high steep slopes, local sections of poor stability, the water north highway, State Road 212 and Jialing River navigation channel poses a threat.
2. Non-metallic mines occupy and damage land resources
Southwest China's non-metallic mines occupy and damage land resources quite prominently, with a total area of 57,855.92hm2, accounting for 30.67% of the total occupied area. Among them, 25398.42hm2 in Yunnan Province, 20941.43hm2 in Sichuan Province, 2334.89hm2 in Guizhou Province, 3755hm2 in Tibet, and 5436.18hm2 in Chongqing, with a larger area of Yunnan and Sichuan, and a smaller area in Chongqing, Tibet and Guizhou.
Sichuan Fulcrum River in Mianyang City, Youxian District, the territory of the flow length of 37.5km, Fulcrum River bed is slow and wide, more gravel and pebbles, so the section of the city of Mianyang City, the construction of sand and gravel become an important source of origin. In the past 20 years, sand and gravel mining in Youxian District amounted to 750×104m3, and about 7.5×104g of sand and gold were extracted, with more than 10,000 employees, forming 2,134 sand and gravel mining sites, with an average mining depth of 5m, and the deepest depth up to 10m, which resulted in the destruction of large areas of arable land and shoals, with a total area of 1,075.75hm2. This caused the destruction of vegetation in the area, soil erosion and obstruction of the river, and jeopardized the development of Mianyang City's construction industry. hazards, and affects the urban safety of Mianyang City.
Photo 3-13 Panoramic view of Guanyin Gorge
The broken mountains and piles of slag formed by massive mining in Guangyuanbao Asbestos Mining Area in Asbestos County, Sichuan Province, cover an area of 200hm2, which not only destroys the ecological environment of the area, but also creates a great danger of mudslides and poses a serious threat to the safety of the National Highway 108 and the Asbestos County city (Photo 3-14).
Photo 3-14 Asbestos Mining Area in Guangyuan Fort, Asbestos County, Sichuan Province
(2) Environmental Pollution of Non-metallic Mines
Southwest China is a large phosphorus-producing region in China, and sulfur mines are rich in sulfur and phosphorus mines, which are important sources of pollution of non-metallic mines.
1. Yunnan phosphorus mine environmental pollution
Yunnan is a large province of phosphorus production, only the Dianchi Basin there are 5 phosphorus mining area 33 phosphorus mining enterprises, mining stripped of waste soil and rock and tailings along the slopes near the quarry and turnip ditch randomly stacked. The total annual slag discharge of the mines is 640.28×104t. The main pollutants in the effluent from these accumulated waste soil and rock and tailings are fluorine and total phosphorus, which are solubilized by atmospheric precipitation. According to the information of Yunnan Provincial General Station of Geological and Environmental Monitoring, the leaching solution of phosphate mine tailings (phosphogypsum) contains Cd0.118mg/L, Pb0.027mg/L, total phosphorus 14,757mg/L, and F5,308mg/L, which pollutes the surrounding surface water and groundwater.
The phosphorus ore processing plant around the edge of the Dianchi pond, in addition to the upper garlic phosphorus ore processing plant wastewater discharge and Jinning phosphorus ore processing plant part of the recycling, most of the rest of the plant wastewater are arbitrarily discharged into the surrounding ditches and streams, or discharged into the tailings storage and then dispersed in the surrounding ditches and streams. Most of the phosphorus mines around the Dianchi pond are in the Dianchi pond recharge, runoff area, beneficiation wastewater and arbitrary discharge of slurry with the surface runoff into the nearby water bodies, polluting surface water; or runoff seepage into the ground, polluting groundwater. Surface water and groundwater eventually converge into Dianchi, aggravating the pollution of Dianchi.
The high phosphorus content of Dianchi water promotes the growth of green algae, which is up to several meters thick at most, and a large number of green algae consume the oxygen in the water, making it difficult for fish to survive and the water body stinks due to pollution. In recent years, the state has allocated huge sums of money to control Dianchi, but still did not get the expected results, only local water bodies have been improved. The reason, the phenomenon of environmental degradation in Dianchi, but the root in the mine.
2. Southern Sichuan sulfuric iron ore mountain pollution of the environment
Southern Sichuan Province, the coal system sulfuric iron ore mountain pollution problem is also quite prominent. The sulfuric iron ore mines in this area were built in 1950-1960, and the mining has caused serious deterioration of the ecological environment of the mines and their surroundings since then.
(1) the local method of refining sulfur yellow pollution. The entire mine is full of refining sulfur yellow earth kiln, refining sulfur yellow harmful gases through the chimney discharged directly into the air, hydrogen sulfide and sulfur dioxide gas concentration in the atmosphere of the mining area increased greatly, soil acidification, plants around the mine is difficult to survive, nearby crops are difficult to grow. After refining sulfur yellow tailings piled up as high as a mountain (only Xuyong County, Dashu sulfuric iron ore area of tailings piled up nearly 1000 × 104m3), filled with the entire mining area, and slag directly to the surface runoff emissions, serious pollution of the environment.
(2) Wastewater pollution. South Sichuan sulfurous iron ore area in the development of sulfurous iron ore, untreated pit water and a large number of beneficiation wastewater, tailing slag, sulfur yellow slag is often discharged into the river through the surface of the streams and ditches, resulting in serious pollution of the river, yellow and turbid, and resulting in the riverbed is constantly raised, endangering the downstream farmland and buildings. And nearly 10% of the sulfur in the ore into the furnace to generate sulfate dissolved by the water into the river, adding to the pollution of river water.
(3) Exhaust gas pollution. Chuannan sulfur iron ore area of air pollution is mainly caused by the use of small clay furnace refining sulfur yellow, due to the refining of sulfur yellow production methods primitive, resource utilization is very low, sulfur recovery between 30% and 40%, only 8% to 10% of the sulfur into the slag, and the rest of the gaseous form of emissions into the atmosphere. According to the industrial pollution survey data, Dashu sulfur iron ore refining sulfur yellow exhaust gas, the annual emissions of SO2 up to 9248t, only this one discount pure sulfur 4642t, not only a waste of resources, but also seriously pollute and destroy the environment around the mine and the ecological balance. In the 1985 physical examination of the mine workers, the total number of sick people was 60.8%, of which 90% of the young and middle-aged earth furnace operators suffered from emphysema, bronchitis, hemoptysis, rhinitis and other diseases (Jiang Jun, 1999; Li Xueren, 1980). This indicates that the uncontrolled emission of large quantities of sulfur refining and yellow exhaust gas in the region has formed an air pollution belt dominated by sulfur dioxide and hydrogen sulfide, which seriously affects the health of the workers.
At present, the only way to solve the exhaust gas pollution is to stop the production of local sulfur yellow refining as soon as possible and introduce smokeless sulfur yellow refining technology. This project is a new technology to develop sulfuric iron ore resources and protect the environment, this technology can make the sulfur dioxide emissions per hour is less than 34kg, hydrogen sulfide emissions per hour is less than 1.3 kg, and refining sulfuric yellow operator can not feel the pungent smell of smoke, and is also very beneficial to the workers labor protection. The use of this new technology also reduces the pollution load of acidic wastewater in the region, which will have a good effect on the improvement of the acid rain condition in the mining area.
Chuannan sulfuric iron ore area slag is still increasing at a rate of nearly one million tons per year, and the ecological environment in the mining area has been seriously damaged. Ecological restoration project is in the pure tailings environment mixed with soil and not mixed with soil for comparison test, choose out such as water candles, leafless knapweed and other plants that can grow and reproduce in the pure tailings slag heap, restoring vegetation, transforming the dust pollution and toxic substances, enhance soil fertility, change the climate of the community, so that the "ripened" land can be planted and cultivated, in order to fundamentally improve the ecological environment. In order to fundamentally achieve the social benefits of ecological restoration projects; at the same time, through the study of refining sulfur yellow slag and sulfur sand tailings, to carry out the recycling of resources, so that the iron content in the slag to the iron ore standard, so that it has the value of the development of the slag, which not only reduces the waste of resources, but also increases the benefits of enterprises, and reduces the pollution of the environment load.
(C) non-metallic mine geologic disasters
Southwest non-metallic mine geologic disasters in Sichuan is more prominent, followed by Guizhou, Yunnan, Chongqing and Tibet.
1. Non-metallic mine landslide geologic disaster
Non-metallic mine landslide geologic disaster in Sichuan Province Emei Jinding Cement Plant limestone mine. The mine has been in operation since 1970, until around 1990 has been the use of large blasting, and has not taken any seismic measures. The powerful blasting vibration acts on the slope, destroying the integrity and stability of the rock body of the slope, and coupled with the influence of rainfall, serious landslide geologic hazards have now developed (Table 3-19).
Table 3-19 Statistics of landslide geohazards in limestone mine of Emei Cement Plant
The landslide in the west mining area is a large rocky traction landslide, and the landslide body has slid down as a whole, with a slide distance of 160m (Li Yungui et al., 2004). From the topographic map before the slide, it can be seen that the front edge of the slope before the slide is a linear steep wall, the steep wall is as high as 20~25m and 190m wide, which is composed of thick massive chert, with a vertical thickness of 30~40m, and there is a weak interlayer under the thick layer of chert (muddy mud chalk chert), and the foot of the slope has been stripped out in the inner part of the mining platform at the bottom of the slope body of 720m, and the east side of the slope body has been cut by the Luo gully, and the west side has been cut by the dissolution gully, and the slope body has been cut by the dissolution gully, and the west side has been cut by the dissolution gully. The east side of the slope is cut by the Luo gully, the west side is cut by the dissolution gully, and there is a tectonic fissure in the slope body with a strike of 45°～135°, and the slope body has been cut into blocks, and the distance between the 720m platform and the plane of the steep wall on the slope is about 120m, and it forms a high steep and medium-high slope with a difference of more than 100m in height from the top. Therefore, on March 15, 2002, after three consecutive days of light rain, the upper slope suddenly slid down, and the "3.15" landslide occurred in the West Mining Area, resulting in eight deaths and a large number of mine facilities were buried. The slide slid 160m (flat distance) along the weak structural surface and fell on the 720m platform, the leading edge reached the 670m platform, the plane was tongue-shaped. The slope of the landslide is triangular in plan, with an area of 12,440m2 and a volume of 37.32×104m3. The area of the landslide accumulation is 6.06×104m2, and the thickness of the landslide is 10-30m, with a volume of about 60×104m3; the residual volume after cleaning up is now about 40×104m3 (Photo 3-15).
Photo 3-15 Sichuan Emei Jinding Cement Plant West Mining Area "3.15" Landslide
The steep wall at the back edge of the landslide is in a straight line, about 45° towards NW, composed of tensile structural surfaces, with strong erosion, and the face of the steep wall has been eroded to be uneven, and stalactites are hanging. The sliding wall is 15-30 m high, the sliding mode is along the layer sliding, the landslide body is a whole slide, the front edge of the slide body rolled down, the back edge of the slide body still has some blocks still retained the original rock layer structure, the top of the slide body retains the residual slope deposits of soil layer and vegetation. The slide body and the slide wall are distributed between the sliding collapse of the accumulation. The east side of the slide bed is exposed, the slide surface is flat and smooth, see calcite film, the morphology of the slide surface is micro-arc type, the azimuth angle of the slide surface is 22°-26°, the inclination angle is 27°-31°, the upper part is slow and the lower part is steep, the scuff mark of the slide surface is clearly visible, the direction of the scuff mark is consistent with the stratigraphic tendency and the inclination of the slip surface as NE22°, the slide surface is composed by the weak and soft structural surfaces in the lower part of the soft and hard rock group, the material of the slide zone is mud-bearing siltstone clasts, biotite clasts The material of the slide zone is mud-bearing chalk, tuff and muddy sandy chalk, with hard medium-thick laminated bioclastic rocks as its slip bed, and the slide body consists of the upper thick-layered bioclastic tuff. Below the steep cliffs of the back wall of the landslide, groundwater was seen to overflow along the slip surface in an intrusive manner after rainfall (Figure 3-7). The slip surface of the landslide is complete, no rupture surface, in the middle of the slip surface at an elevation of 770m to see a vertical shaft-like cave, hole diameter 30m, the hole is semicircular, vertical depth of 15m, the bottom of the cave sidewalls with the development of branch holes. The cave is exposed after the overlying rock body slipped off in this landslide.
After the occurrence of this geologic disaster, the geological environment of the mine was surveyed and evaluated to find out the cause of the geologic disaster and formulate the next safe mining plan.
In addition, the southern Sichuan Xuyong area of sulfuric iron ore mountain landslide geologic disaster is also more serious. Such as Xuyong Dashu sulfide iron ore at the end of March 1990, the west section of the river eagle rock foot of the slope appeared a number of surface cracks, the development of rapid, due to the surface cracking and sliding, resulting in the collapse of the mine's staff quarters more than 20, more than 100 families of housing, as well as the ground, the walls cracked and severely tilted. Another 443 homes of employees, as well as buildings such as the mine's clubhouse, are now damaged or threatened.
Figure 3-7 Schematic diagram of the current status of the landslide in the West Mining Area of Sichuan Emei Jinding Cement Plant
1 - second weak layer (mud layer); 2 - third weak layer (mud layer); 3 - dissolution gully; 4 - landslide accumulation body; 5 Lower Permian six-section tuff; 6-Lower Permian five-section tuff; 7-Mud tuff
The formation of geologic hazards is not only related to the undulating topography and landscape of the site and the complex geologic environment conditions such as the soft and hard Triassic Feixianguan Formation and the soft Quaternary slope deposits, but also related to the anthropogenic It is also closely related to the anthropogenic activity factor - underground mining. The deformation and collapse of the roof plate of underground mining (including coal), which causes the destruction of the overlying rock layer and the subsidence of the ground surface, is the most important activity factor that causes and induces many kinds of disasters. The Dashu sulfide iron ore area was dotted with small coal kilns in the 1990s. According to the estimation of daily coal production and mining time of the small coal kilns, the small coal kilns have accumulated about 4×104t of coal, which translates to a mining area of 3.6×104m2. According to the information of other coal mines in China, the general area of the mining area reaches 1,000 to 3,000m2, and the ground surface is likely to produce movement and deformation. The location of the existing surface generating 3 cracks basically matches with the mining hollow area. This indicates that the cracks generated on the ground surface are caused by the long-term mining of small coal kilns, and induced the movement and deformation of the overburden.
Meanwhile, there are more types of hazards in the area. In addition to avalanches and landslides, there are also environmental geological problems such as flash floods and mudslides (including water-rock flows), environmental pollution, blockage of rivers, river-bed elevation, highway pavement destruction, and tailings slag occupying the land (Photo 3-16).
Photo 3-16 Dashu Sulfide Iron Ore Slag Washed into the River
2. Geological Disasters of Mud and Stone Flows in Non-Metallic Mines
Southwest China's non-metallic mines are dominated by torrential rainfall-type geologic disasters, which are more prominent in old mines. Such as Guizhou Kaiyang phosphorus mine, Sichuan asbestos mines have occurred in a larger scale of mudflow geological disasters.
In the late night of June 24, 1995, Kaifang County, Guizhou Province, Jinzhong Town, a series of heavy rainfall, induced mudslides, landslides, the volume of about 200 × 104m3. Jinzhong Town and the Kaifang phosphorus mines were affected by a large area of the town, washed away the factory buildings, homes 11606m2, buried 27179m2, flooded mine 4910m, 645 sets of equipment, washed away the water supply pipeline 21800m, the main line of power supply and communication 7.6km2. Communication trunk line 7.6km, 77km highway, 2 bridges, river embankment 10km, 36 culverts, affected 464 households, *** count 13012 people, 25 deaths, 18 injuries, direct economic losses of 205 million yuan.
Sichuan Xinkang Asbestos Mine also had a mudslide. The mine is located on the downstream slope of South Dahonggou in Asbestos County, Ya'an City, with Dahonggou as its earth discharge site and tailings storage. In order to separate the water from the rock, the upper part of the discharge field was constructed with interceptor dams and flood diversion tunnels; the downstream slag dam and spillway were constructed by directional blasting method: there are now slag and tailings accumulations of 2,100×104 m3 in the reservoir.On April 6, 2001, due to the upstream repair of the discharge tunnel, when it was raining, the temporary downstream release of floodwaters triggered slag mudslides (hydrological flows), which partially overtopped the dam, and the mudslides were discharged 30×104 to 50×104 to 50×104 to 50×104 to 50×104 to 50×104 m3 in the lower part of the dam. Diarrhea 30 × 104 ~ 50 × 104m3, so that the downstream bamboo river silt height of 8m, along the river power station and other enterprises were damaged, direct economic losses of more than 1 million yuan, and threaten the downstream South Branch River coast and the safety of asbestos county. Sichuan provincial government paid great attention and invested 4.8 million yuan to complete the emergency treatment in September 2001, the main works include: ① using lead wire block gabions to repair the slagging dam (washed out section of the floodway) (Photo 3-17); ② reservoir cleaned up the flow channel; ③ raised the upstream interceptor dams, repaired the flood tunnel; ④ in the upper reaches of the additional grille dams. Through the above treatment works, the threat of mudflow from the tailing pond was initially lifted.
Photo 3-17 Spillway on the tailing dam of Xinkang Asbestos Mine, Asbestos County, Sichuan Province
3. Non-metallic Mine Collapse Geological Disasters
Non-metallic Mine Collapse Geological Disasters are often related to unregulated and irrational mining.On September 6, 2001, a collapse occurred in Guanzhongtian Dapo quarry in Yutang Village, Xinyao Township, Liuzhi Special Administrative Region of Guizhou Province, in which 15 people were killed and 2 were injured. . The collapse body was about 73m long, 75m wide, 5-15m thick, with a total cubic volume of about 2×104m3. The outcrop of the quarry was thin-middle layer of thick laminated gray rock of the Lower Triassic Yongning Town Group, with several layers of 2-5mm mudstone, and two groups of 143° and 225° fissures were developed in the rock. The collapse occurred mainly due to the unfavorable combination of conditions of the rock layers, the layers are sandwiched between the weak layer, dissolution fissure development, due to water infiltration of the rock layer strength is reduced; at the same time, unreasonable human engineering activities, so that in the early 1990s the construction of the simple highway old cut slopes, partially or partially cut off the weak layer, the farmers quarrying to form the proximity of the face, so that has been very fragile rock equilibrium was broken, instantaneous rapid collapse, and caused geologic disaster. The geologic disaster.
February 16, 2003, 23:30, Sichuan Province, Yibing City, Gyunlian County, the patrol division of the town patrol division of the village of the seven groups of the joint cement plant on the east side of the body of the dangerous rock suddenly collapsed, destroyed the cement factory building 500m2, 3 people died, 1 person slightly injured in a serious disaster. A large amount of mining equipment was damaged or buried, causing direct economic losses of 2 million yuan. The volume of the collapse was about 500m3, the falling blocks were irregularly shaped, generally about 3m in diameter, the largest up to 6m, the largest block volume of the collapse site was about 100m3. The patrol division of the town from the county seat of Gyunlian County, 14km, the terrain and geomorphology of the dissolution tectonics of the low and medium mountains. The exposed stratum is the Permian Maokou Formation (P2m) medium-thick laminated tuff sandwiched between bioclastic tuff, and the rock body is produced at 215°∠18°. The limestone rock joint fissure development, rock body integrity is poor. 1992 patrol division joint office cement plant construction, the location of the mountain slopes carried out a certain degree of sloping treatment, cement factory plant was built in the height of about 20m steep cliff side, the limestone body development of three groups of joint fissure, by the joint surface and the impact of the rock surface, the rock body is cut into varying sizes of the dangerous rock body, for a long time, the groundwater transported in the fissure, erosion Rock body, so that the rock body between each other shear strength is reduced, under the action of gravity, the dangerous rock body from the parent rock body collapse, the formation of the collapse disaster.
At present, the collapsed rock body is basically stable, but on the other side of the collapse (cement factory quarry side) there are still thousands of dangerous rock body, in the quarrying of artillery and rainfall triggering effect, there is a possibility of collapsing again, a direct threat to the cement factory factory buildings and staff safety, should be avoided.
Panzhihua City, Sichuan Province, Panzhihua City, Pangang limestone mine is located in the upper part of the mountains on the right bank of the Zhaoguan River, is the production base of auxiliary raw materials of Pangangang. The mine area is characterized by steep topography, complex tectonics and rock fragmentation. The stratigraphic lithology is Permian tuff, monoclinic output, inclination and slope direction consistent, rock dip angle 23 °. The mine uses perforation, blasting and other methods of open-pit mining, annual mining of limestone ore about 120 × 104t.
In the short period of 8 years from 1980 to 1988, the west side of the quarry mountain body occurred three consecutive large-scale collapse, the total amount of collapsed body reached 398 × 104m3.The first collapse occurred on November 8, 1980, located in the eastern part of the platform of the ＋1400m. The first collapse occurred on November 8, 1980, above the eastern part of the +1400m platform. Mainly along the joints and fissures and the level of occurrence, the formation of the collapse body 46m long, 65m wide, 6 ~ 35m thick, volume of 5 × 104m3. The reason for the formation of the quarry ＋1400m level using the chamber blasting, along the strike of the formation of the 1400m horizontal steps cut off the ore layer of the "root foot", so that the quarry slope foot to form a high about 245m of airspace. The second collapse occurred on June 10, 1981, mainly on the basis of the development of the first collapse, the collapse volume of 392 × 104m3, the formation of the reasons for the formation of the first collapse is basically similar to the formation of the third collapse is located in the northwest of the quarry to the west of the F8 fault, occurred The third collapse is located in the west of F8 fault in the northwest of the quarry, occurred on October 13, 1988, the collapse body is 100m in length from north to south, 350m in width from east to west, the volume of the collapse is about 1.0×104m3, and the blasting vibration is too big and the excavation of the high slope is still the main reason for its formation.
Three times the collapse of the pile covered one-third of the area of the quarry, so that the western mining of the mine 1400 ~ 1363m 4 production steps all interrupted mining, the length of the quarry east and west is reduced by 450m, 2800 × 104t of high-quality ore was overridden, to the mine traffic and mining has brought great difficulties. Now, the west side slope forms a steep cliff with a height of about 100m, and the upper part of it has a more obvious cracked area with poor stability. In addition, due to the loose structure of the collapse pile, the slope of the pile is larger, the stability is poor, and it is easy to form a landslide or mudslide disaster under the action of rainwater.
4. Non-metallic mine ground subsidence geologic disaster
Non-metallic mine ground subsidence is similar to other types of mines, are related to the mining hollow area. Plus hydrogeological conditions and the impact of blasting vibration caused.
On June 13, 1999, at 10:50, the ground of the ShuiMaGou slope suddenly collapsed in the fifth group of the fourth village of Hongbai Town, Shifang City, Sichuan Province, forming a circular collapse pit with a diameter of about 5m and a depth of about 6m, which caused one of the housing units of YueJiShan branch mine of JinHe Phosphorus Mine to fall and three outsiders living therein to be buried by the fall. In addition, Shuimo ditch collapse pit slope still live in four villages, five groups of 13 villagers, the vast majority of residents of the house cracks, ground cracking, crack width 0.1 ~ 3cm ranging from 0.2 ~ 0.8cm, mostly in the length of a few meters to a dozen meters ranging from the north-east - south-west direction, part of the north-west - south-east direction. The concrete floor is cracked and sunken, and there are cracks at the intersection of vertical and horizontal walls of the houses, doors and windows of the walls, and other weak parts of the construction. The cause of the ground collapse is related to the deformation of the roof plate of the mining area and the vibration of mining blasting.
In summary, the environmental geological problems of energy mines in Southwest China are dominated by water pollution, air pollution, landslides, mudslides, ground subsidence, and occupation of land resources; the environmental geological problems of metal mines are dominated by pollution of heavy metal elements, landslides, mudslides, and soil erosion, etc.; and the environmental geological problems of non-metal mines are dominated by destruction of landscape resources, destruction of land resources, pollution of sulphur and phosphorus chemical materials, and geological disasters such as landslides , mudslides and other geological disasters, indicating that different types of mines form different environmental geological problems (Table 3-20).
Table 3-20 Major Mine Environmental Geological Problems in Southwest China
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