"8" Debris Flow in Lucaogou Mining Area, Manas County, Xinjiang

From August/4, 2065 to August/7 ~/9, 2065, a sudden rainstorm occurred in Lucaogou mining area in Manas County, Changji Hui Autonomous Prefecture, Xinjiang, causing floods and mudslides. Floods and mudslides have caused some damage to Tianan Coal Mine and Yuanfeng Coal Mine in the mining area. However, due to the timely and accurate early warning and forecast, the personnel on duty in the mine immediately started the emergency plan for disaster prevention before the outbreak of mountain torrents and mudslides, and the threatened personnel were transferred urgently, causing no casualties, and successfully avoiding the property loss of 50 people of 6.5438+0 million yuan.

Floods and mudslides have caused some damage to the industrial square, staff quarters, warehouses and electrical equipment in the mining area, and the direct economic loss is estimated to be about 400,000 yuan.

After receiving the disaster report, five people, including the leaders of Manas County Land and Resources Bureau, arrived at Lucaogou mining area on the morning of August 15 10 to investigate the disaster. It is required that the mining area should pay close attention to the weather changes while cleaning up the deposits in the mining area and further take preventive measures. Workers are not allowed to live in the dormitories built in the valley, and all of them must be moved to the safety zone of the office building, and at the same time, the monitoring of the valley upstream of the mining area should be strengthened.

2 General situation of geological disasters

2. 1 Basic information

Lucaogou is a tributary of the upper reaches of Manas River, and its recharge sources are mainly glacial snowmelt water and atmospheric precipitation. The valley only has short-term water flowing into Manas River in the spring snow melting or summer and autumn rainy season. The gully that caused the debris flow disaster this time is a branch gully of Lucaogou, with an altitude of1000 ~ 2,000 m, the gully is due north, the longitudinal slope of the gully is reduced to 270‰, and the drainage area is about 4km2. Usually it is a dry ditch, and when it rains or melts snow, it forms a confluence in the ditch.

The strata in the mining area are mainly composed of conglomerate, sandstone, mudstone and coal seam of Permian and Jurassic. The material sources of debris flow are mostly slope deposits, debris and stones formed by weathering, collapse and falling on both sides of the valley. The slope on both sides of the valley is 25 ~ 45, and the vegetation is well developed.

On August 14, the precipitation in Manas Nanshan mining area was 6 ~ 12 mm, which was moderate rainfall. Due to the local heavy rainfall in mountainous areas, it was found that the rainstorm was the largest in history in 10 years. After the disaster, Tianan Coal Mine was only partially destroyed by the flood, with little loss. The flood and debris flow accumulation filled the spillway ditch with a length of 80m, a width of 5m and a depth of more than 2m on the south side of Yuanfeng Coal Mine canteen. Debris flow broke through the flood dam near the canteen in the mining area and rushed into the garden, staff dormitory, staff activity room and other houses on the north side of the canteen, and the indoor water accumulated was 1m deep (containing a lot of sediment). The flood washed away the road, forming a deep ditch1.5m. After the flood and debris flow, mud and gravel blocks with a thickness of 1 ~ 2m were piled up in the staff quarters and industrial squares, which is roughly estimated to be about 1500m3, which is a small water-rock flow disaster.

2.2 Cause analysis

The southern mountainous area of Manas County is located on the northern slope of Tianshan Mountain, with abundant precipitation and developed debris flow disasters in Lucaogou, which is a high-risk area of geological disasters. Debris flow disasters mostly occur in April-September when snow melting and precipitation are abundant in spring. This rainstorm is the largest in the history of 10, and it is the main factor causing debris flow disaster. The valley is narrow and the slopes of the mountains on both sides are large, so it is very easy to form confluence. The lithology of strata in the mining area is easily weathered sandstone and mudstone, and the material source of debris flow is the debris slope formed by weathering and peeling of rocks on both sides of gully and early accumulation in gully. The boundary between the formation area and the circulation area of this debris flow is not obvious. The valley at the disaster site has both accumulation and erosion, and the valley is both a circulation area and a formation area. The landform and lithology of the mining valley are conducive to the formation of debris flow, and heavy rainfall is the most important factor leading to this debris flow disaster.

Figure 1 Debris flow accumulation in the ditch

Figure 2 Threatened staff quarters in the valley

Fig. 3 Gully upstream and accumulated rubble

Figure 4 Landform of Mining Area and Surrounding Area (south)

3. Geological hazard inspection and monitoring

3. 1 Daily inspection and monitoring

Lucaogou mining area in Manas county is a key area for geological disaster prevention and control. Manas County Land and Resources Bureau will assist the government and mines to sign the responsibility book for geological environment protection every year, issue disaster prevention cards and disaster prevention cards to the mining areas, publicize and educate the personnel in various mining areas about the knowledge of geological disaster prevention and avoidance, and enhance their awareness of disaster prevention and avoidance. In view of the prevention and control of geological disasters in mines, the Xinjiang Department of Land and Resources specifically requires land and resources departments at all levels to carry out the investigation of hidden dangers of geological disasters in construction projects and mining areas during the flood season this year, and further implement the responsibility of mine disaster prevention and control. In flood season and rainy season, 24-hour monitoring is carried out, information is kept unblocked, and records of on-duty and dynamic monitoring are made, which ensures the normal development of prevention and early warning of geological disasters and the safety of life and property of mine workers.

3.2 Disaster emergency early warning mechanism

The three levels of land resources and meteorological departments of the autonomous region, Changji Prefecture and Manas County jointly carry out meteorological early warning and forecast of geological disasters. On August 3, 20 13, 13, the county land and resources bureau and the meteorological bureau jointly released the meteorological warning information of rainfall meteorological process and geological disasters, and then the county land and resources bureau timely notified the relevant towns and mining areas in the geological disaster warning area. From August 14 17 to 19, a sudden rainstorm occurred in Lucaogou mining area in Manas County. Before the rainstorm, the personnel on duty in the mine immediately launched the emergency plan for disaster prevention, and urgently transferred 50 threatened people to safe areas such as office buildings in the mining area. After receiving the disaster report, five people, including the leaders of Manas County Land and Resources Bureau, arrived at Lucaogou mining area on the morning of August 15 10 to investigate the disaster. According to the field investigation, mining enterprises are required to take further preventive measures and arrange personnel to continue to do a good job of monitoring and duty.

4. Safe haven resettlement for geological disasters

Due to the timely and accurate early warning and forecast, before the mudslide broke out, the mine urgently transferred 50 threatened people, escaped to the safety zone of the mine office area, and carried some production materials. Due to the advance forecast and effective measures for disaster prevention and avoidance, the debris flow disaster did not cause casualties.

After the disaster investigation, Manas County Land and Resources Bureau issued rectification notices to Tianan Coal Mine and Yuanfeng Coal Mine, requiring the mine to hire relevant experts to make scientific plans for the prevention and control of geological disasters in the mining area. While cleaning up the deposits in the mining area, it is still necessary to pay close attention to the weather changes and take further preventive measures. Dormitories built in the valley are not allowed to live any more, and they must all be moved to the safety zone of the office building. At the same time, it is required to strengthen the monitoring of the upstream valley of the mining area. Once signs of geological disasters are found, the emergency plan should be started immediately.

5 Experience and Enlightenment

This successful hedging shows that a solid foundation for geological disaster prevention and control is the key. At the same time, we should also see that the prevention and control of geological disasters in mines is the focus of our future prevention and control of geological disasters.

(1) A solid foundation for early warning of geological disasters is the key. Before the occurrence of geological disasters, the county land and resources bureau and the meteorological bureau made a more accurate meteorological early warning and forecast of geological disasters, and informed relevant personnel in time. The underground personnel on duty can immediately start the emergency plan for disaster prevention, evacuate personnel from the dangerous area, avoid casualties and reduce property losses. The basic work of geological disaster prevention in peacetime is the main reason for this successful hedging.

(2) Implement mine geological disaster monitoring and early warning personnel and strengthen training. With the development of economy, mining activities are increasing day by day, and geological disasters in mining areas are the key areas in Xinjiang and even the whole country in recent years. It is an important way and means to further strengthen the awareness of mine geological disaster prevention and control responsibility and the training of prevention and avoidance knowledge, and it is also helpful to gradually improve the plan and enhance its effectiveness and operability.