1. Analysis of waterlogging factors in minefields
1.1 Mine water filling factor
1.1.1 Atmospheric precipitation: Atmospheric precipitation is the main source of groundwater supply in this mine area, and it is also the main factor for water filling in mine pits. According to the on-site measurement of the production technology department, in the relationship between the amount of water inflow from the mine and the amount of precipitation, the trend of the water inflow curve and the precipitation curve are basically the same, and the “peak†and “valley†boundaries appearing in the rainy and dry seasons are clear.
1.1.2 The Permian Lower Tongtongzi Formation fine sandstone fissure confined water: The Tongziyan Formation is the main stratum exposed by the tunnel engineering. The fine sandstone fissure confined water aquifer is mostly the top and bottom of the coal seam. When the lane engineering reveals the fine sandstone aquifer, the groundwater in the aquifer will enter the eight lanes, which becomes a direct factor for the mine to fill the water.
1.1.3 Influence of faults on mine water filling: The water conductivity of mine water guide and local water-conducting fault is weak, and the water in fault fracture zone will supply the small sandstone aquifer of Tongziyan Formation, which becomes the water filling factor of mine pit. A part of the groundwater is still stored in the local fault fracture zone. When the well roadway project is exposed, it will protrude into the roadway, but the water inrush time is short and the water volume is small, except for the F2 water-conducting fault of Yongfeng Dongjingtian. No water-filled faults with strong water conductivity were found in the roadway engineering, which had little effect on the filling of the pit.
1.2 Flooding situation in minefield: With the increase and collapse of the goaf after mining small coal in the minefield, the minefield is connected with small coal on the surface, and some goafs pass through the surface, after heavy rain or continuous rainfall, flow into the underground through the seepage channel. The amount of water in the well has increased significantly. For example, the normal level of the first level (+500m) of Xianting Mine is 461.7m3/H, the minimum is 128.64m3/H, and the average is 294.79m3/H, but the maximum amount of continuous storm water inflow is more than twice the normal water inflow. At the same time, due to the infiltration of surface water, some mined areas in the mine field and the water flowing out of the mountain alone formed a flood.
2. Mine water damage prevention and control measures
2.1 Technical basis work
2.1.1 Reasonable development and exploitation. Mines should carefully select the location of the roadway, and strive to avoid passing through the strong aquifer and large fracture zone. There must be enough safety coal pillars from the high-pressure aquifer. The bottom yard should be equipped with water tanks and drainage equipment to meet the maximum water inflow of the mine. Drainage requirements.
2.1.2 Basic hydrogeological basic work of the mine. First, it is necessary to establish and improve the basic hydrogeological data and drawings of mines to provide technical support for water prevention and control work. 1 Establish various types of hydrogeology accounts and materials: the results of hydrological observations of mine water inflows; meteorological data accounts; surface hydrological observation results; mine water inrush point cards or ledgers; poorly closed drilling accounts; Hydrogeological drilling account; other such as surface small coal inspection records; mine water prevention work documents, plans, summary, precaution measures. 2 should, establish and prepare hydrogeological drawings: mine hydrogeological map; hydrogeology histogram: hydrogeological profile; mine water filling map; mine water inflow and various related factors dynamic curve; mine water system map. Second, we must pay attention to the daily business of hydrogeology, and provide parameters and basis for water prevention and control work: 1 Collection of meteorological data. The collected contents mainly include rainfall and evaporation; pay attention to the climate change in the rainy season, and keep abreast of the meteorological dynamics during the rainy season. 2 Investigation and data collection of old kiln and small coal mining. Focus on investigating and mastering the situation of small coal and abandoned old kiln that are currently being mined within the mining area. On the map, the location, scope, mining situation, mining life, water accumulation, isolation of coal pillars, and spatial relationship with large mines are accurately indicated on the map. 3 Mine water inflow observation work. The mine should be observed in the main mining area, main main road and Shimen point, and set up permanent observation stations, usually 1-3 times per month, and the number of observations during the rainy season should be increased 2-3 times. And establish an observation account. For the newly revealed water outlet points and the collapsed water surge points, the number of observations and observation time should be increased. In order to grasp the changes in water volume and establish an observation account. 4 The downhole water in each mine, the main water inrush point in the flood season, the prevention water or the “three prevention†facilities must be marked on the mine water filling map.
2.1.3 Leave the horizontal horizontal coal pillars of the mine as required. Determining the size of horizontal water-separated coal pillars is a complicated problem. According to the requirements of the Mine Hydrogeology Regulations, according to different situations, empirical data with similar hydrological conditions should be selected as the design of horizontal water-separated coal pillars to effectively prevent the upper level. Water seeps into the lower level.
2.1.4 Seriously do a good job in the investigation of small kiln on the surface. Each mine should be based on the combination of geological data and on-site investigation, and ask the old comrades to combine the on-site investigations to do the investigation, measurement and mapping of small kiln within the mining area, and investigate through the small kiln on the surface. Find the channel through which surface water seeps into the well. At the same time, timely measures are taken to block the drainage channel and prevent surface water from seeping into the well.
2.2 Surface water damage prevention
2.2.1 Grasp the daily inspection and cleaning and maintenance of surface water control projects. Mines should carry out daily inspections and cleaning and maintenance work in the mine area according to the scope of the mining industry. In particular, before the rainy season, check the surface drainage ditch and flood control dams, drainage culverts and other flood control facilities to prevent or reduce water facilities through the ground. Atmospheric precipitation and surface water seepage into the well, it is the first line of defense to ensure safe production of mines.
2.2.2 Fill the surface fissure zone and the drainage channel. The disorderly mining of the surface small kiln destroys part of the surface cover and the security coal pillars, forming a gap zone on the surface of the well field, which is easy to become a channel for rainwater or surface water to seep into the well. therefore. It is necessary to strengthen the treatment of surface fissures. The main method: 1 stuffing the collapse crack. The trench can be trenched along the seam, the depth is 0.4-0.8m, the width of each side of the crack edge is 0.3-0.5m, the stone or stone is filled in the seam, and the upper part is filled with 3:7 lime soil (ash ratio: 3:7). Honest. 2 Fill the collapse pit. Backfilling collapse pits should generally be at the bottom of the water-conducting collapse pit. First use scrap Steel Pipe, scrap steel rail or waste steel wire rope as the skeleton, put enough trees and grass bunches into the pit, and then continuously put sandbags and stones, and then use a large number of stones. Filling is carried out. Finally, the cement is used to grind the stone in the upper part of the stone, and then the 3:7 lime soil (the ratio of sand to sand is 3:7) is compacted to block the passage of the water flow and reduce the water seepage in the surface subsidence area. The Xiaohua Coal Mine in the Beijing mining area has greatly reduced the surface water infiltration into the well by using the surface crack zone.
2.2.3 Construction of surface drainage and drainage facilities. In order to reduce the replenishment of surface water and Quaternary diving to the mine aquifer, C20 concrete can be used to build impervious diversion trenches in the surface leakage area. When the surface water leakage in the mining area is very large, and it is difficult to use the above water blocking method, the water flow can be diverted, and the new water ditch can be manually excavated to introduce the surface water to the normal drainage system.
2.3 Prevention of underground water damage
2.3.1 Strengthen daily inspection and cleaning and maintenance of underground drainage and drainage facilities. Before the rainy season, the mine should conduct a major inspection of all the drainage and drainage facilities, and clean all the drainage ditches and water tanks in the underground to ensure the smooth flow of the water ditches and the water storage capacity to reach the proper capacity. At the same time, during the rainy season, a patrol is organized once a week, and measures are taken to carefully carry out measures such as interception and dredging. As far as possible, the upper pit water is discharged from the main raft, and it cannot be discharged from the main shovel. The water is introduced into the bottom water tank and discharged to the ground through the central pump so that it does not penetrate into the lower level.
2.3.2 Do a good job of the exploration and release water in the mining face. In the minefield area of ​​the mining area, there may be small kiln filled with water and a single head down the mountain. When the mine is re-extracted in the old area, when the mining face is close to these water bodies, it may cause a water inrush accident. Therefore, in the production process, 60 meters should be pushed outside the water-storage area as the water-exploration line, and the principle of “deep exploration, first exploration, and first exploration†should be adhered to.
2.3.2.1 Main technical parameters of water exploration and drainage. 1Super-front distance: When the roadway is dug into the water-probing line, it is difficult to find the old-fashioned water in one operation in practice. Generally, it is necessary to insist on the combination of water exploration and excavation, and then digging after exploration, re-exploration after excavation, and circulation. Work. In this process, the position of the final hole of the water drilling hole should always be kept at a distance from the front roadway. The number of lead distances should be calculated according to the parameters of coal (rock), coal seam thickness and water pressure. The calculation formula is as follows:
a - lead (m);
L——the span of the roadway (width or height is the largest) (m);
P——head pressure (kg/cm2);
KP - tensile strength of coal pillars (kg / cm 2 ).
According to the thickness of the coal seam, the hardness of the coal seam and the top and bottom of the coal seam, as well as the practical experience on the site, the general medium-thick coal seam has a lead distance of not less than 20m, and the thin coal seam can be appropriately shortened, and the minimum is not less than 8m. 2 helping distance: the water drilling hole in the roadway heading. Radially arranged to the front, generally no less than three, the distance from the central eye to the external oblique eye is generally 20m. 3 Drilling density: The drilling density depends on the size of the old lane, and generally does not exceed 3m.
2.4 Institutional assurance measures
2.4.1 Improve the responsibility system for mine water prevention and control work. The mine manager is the first person responsible for the mine water prevention and control work. The chief engineer of the mine is the main responsible person for the mine water control technology management work. At the same time, it is clear that the mine management personnel are responsible for the daily work of water prevention and control, and the responsibility is to the people, and the effectiveness of the work is taken as a part of the year-end performance appraisal of the relevant personnel, and the work responsibility and work quality of the relevant personnel are improved.
2.4.2 Strengthen the daily inspection and maintenance of the mine drainage system. The mine should carefully organize the inspection of the whole mine drainage system every month, and timely correct the existing power supply, equipment and pipeline problems. At the same time, a joint drainage test of the mining area should be carried out every year to ensure that the drainage power supply system is in good condition; the flood control and emergency materials reserve of the flood control material warehouse on the ground and underground should be carefully done.
2.4.3 Establish a mine joint prevention and control water work system. Adjacent mines should cooperate with each other, participate in the project, discover the dangers and timely report, share the mine water prevention and control technical data, and jointly control the mine water damage.
3, the conclusion
Mine waterlogging prevention and control work is a multi-disciplinary, multi-sectoral, multi-unit work. In addition to the above four aspects of work well, we must continue to analyze, research and summarize, to find out suitable for mine water damage prevention and control. Specific measures are put into practice to prevent the occurrence of water damage accidents.
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