How to carry out the exploration and drainage of the working face
With the continuous expansion of society's energy needs, coal market, more and more optimistic about the market, the size and scope of expanding coal mining, coal mining history combined with a long length and small towns and even abuse of individual coal mines open Luancai, forming In many goafs, some of these goafs are connected to the surface rivers, and some of them are due to the accumulation of production water during mining, as well as the accumulation of water in geological aquifers, etc., which pose a threat to the safety of new coal mines. Therefore, before the mining of new mines, mining areas and working faces, detailed geological exploration work must be carried out, and the exploration and release work should be carried out on the old air and aquifer that may threaten the working face, so as to eliminate hidden dangers and ensure safety. According to the production nature of the exploration and drainage work, it can be divided into the exploration (drilling) working surface exploration and release water and the mining work surface to explore the water; according to the different high-level positions of the exploration water, it can be divided into the adjacent (upper or lower) layer to explore the water and the layer. Exploring and releasing water; depending on the location of the exploration water, it can be divided into old air and water and aquifer water. Let's talk about our own experience on the work of the Yangquan Yinying Coal Mine on the upper level of the mining face of the 804 panel.
1 Basic situation of the 80401 working face for water exploration
The overall terrain of the 80401 working face is: high in the northwest and low in the southeast. The coal seam is approaching the east-west direction and sloping southward, with an inclination of 2° to 8°, with an average of 5°. In front of the work, the length of 330 m is 110 m, the length of the rear 560 m is 140 m, and the length of the trough is 890 m. The contour line of the coal seam floor is +824 m~+830 m at the cut of the working face, and the upper line of the upper 2.33 m coal seam is +870 m~+872 m. The working face is mined with 82# coal seam, which has a simple and stable structure, with a thickness of 1.2 m to 1.9 m and an average of 1.6 m. The local part contains 0.02 m to 0.30 m of carbonaceous mudstone interlayer. Of stable coal roof slate, shale comprising a pseudo top 0.4 m, 13.85 m of fine sandstone, sandy shale and mudstone immediate roof, 20.33 m in the sandstone roof; roof seam joint fractured, partially broken roof strata The lithology of the floor is stable sandy mudstone. The upper part of this work is the 30118 working face goaf of No. 3 coal seam of this mine and the No. 3 coal mined area of ​​No. 1 coal mine of Yangmei Group. It is expected that there will be old water and the gas content is large. The working face is a high-grade general mining working face, adopting the inclined longwall receding coal mining method and the roof management method of all the slumping methods.
2 Ways to explore water
(1) According to the “difficult to explore†principle of exploration and release water and the geological exploration data provided by the geological department, compile corresponding technical measures for safety of exploration and release water. The drilling parameters shall be determined according to the point of penetration of the borehole at the lowest point of the upper stratum and the opening point of the borehole shall be at the lower roadway of the working face of the stratum, and the drilling distance of the borehole shall be as short as possible. The principle requires that all relevant personnel must be implemented before starting work.
(2) Do all the preparatory work required for the construction of the exploration and discharge water, including the rig and its interview operation, the spare parts of the spare parts, the power supply system of the underground drilling rig , the water supply system, the drainage power supply system, and the water pump and piping system.
(3) When operating, the direction of the drilling parameters should be strictly followed, and the direction should be identified by the measurement department, and the drilling and preliminary drilling work should be supported by the professional. In order to control the amount of water discharged according to the situation when the upper layer of water is lowered, in the initial drilling, a large drill bit (diameter 120 mm in order to install a 100 mm diameter iron pipe) is passed through the direct top of the coal seam (due to the direct top) It is not stable, and when the upper water pressure is large, it will seep out water from the cracks in its rock formation). The drilling depth is generally 2 m to 4 m, which is mainly for the purpose of inserting a pipe with a diameter of 100 mm (hereinafter referred to as a water control pipe) and installing a water control valve.
(4) There are two ways to install the water control pipe: one is to wrap the cotton sleeve or palm fiber around the tube, and it is wrapped with wire and sturdy, and then it is placed in place by the rig pushing and hammering, in order to prevent water pressure in the hole. If the pipe body is too large, the pipe should be broken under the flange of the water control pipe. The top of the column is applied to the large iron plate around the pre-welded flange. The iron plate can also be used. The roots are lifted to enhance the stability. The iron plate is square or round and has an area of ​​about 0.15 m2. The other is to install the mixed cement mortar from the water control pipe (not too thin, and a certain proportion is added). Accelerator), the number of which is about 1/2~2/3 of the length of the tube, and then make a mortar in the top of the piston tray to make the mortar out of the tube for a certain length (about 20 cm ~ 30 cm) It can be smeared on the wall of the hole, and at the same time slowly hit or push the water control pipe so that the outer wall of the water control pipe and the inner wall of the drill hole can be filled with mud, so that the water control pipe can be firmly inserted into the hole, and then it should be installed in time. Water control valve.
(5) After the water control pipe is installed, normal drilling work can be carried out. When drilling, the top thrust of the rig should not be too large to prevent the bit from falling off or the direction of the drilling to be deviated. Before the hole is drilled, it must be ensured that the drainage system is safe.
(6) When draining, install the corresponding pump and piping according to the amount of water. The drainage location can be set in the two lanes or the tail lane depending on the situation, or it can be installed at both the channel and the tail lane. The 80401 working face is used for water exploration and drainage. When draining, 45 kW water pump and d 100 mm pipeline, 55 kW water pump and d 150 mm pipeline are installed in the return air tank, and 45 kW is installed in the tail lane. A set of water pump and d 100 mm pipeline, the water on the return air side can be discharged to the tailgate through the through-hole preset pipeline of the tail lane. In this way, on the one hand, the water volume can be adjusted according to the integrity and drainage capacity of the water pumps on both sides; on the other hand, the roadway equipment can be prevented from being crowded and affecting ventilation, safety, transportation and pedestrians. In addition, in the return air duct, a small reservoir can be excavated by one side lane to remove the water in the roadway as cleanly as possible, thus creating conditions for pedestrians and transportation.
In order to speed up the drainage speed, you can use a few more eyes (3 to 5), connect them to the same line, and use a pressure pump to discharge the water once or twice (set the reservoir) Alley ditch. In this way, the amount of equipment used and energy consumption can be reduced, and the efficiency of drainage can be improved. After using this method, the 80401 working face shared the upper layer of water (about 210,000 m3) in 88 d, which was 2 to 2.5 months earlier than the expected drainage period.
3 Things to be aware of
(1) Managers, especially those at the decision-making level, must attach great importance to the exploration and release of water work, and cannot produce paralysis. The 80401 working face is in the case that no water is detected according to the 80405 working face and the 80403 working face. The production and technical departments at all levels rely on subjective imagination to think that there is no water in this working face and no thought even if there is water. Left and right, leading to a tense and passive situation after work.
(2) It is necessary to do a good job of preparation and to conduct water for exploration in advance. The advance time is generally 2 to 3 months, so as to avoid the phenomenon of affecting production and work. The 80401 working face is put down when the initial mining advances 20 m to 30 m. The entire panel is forced to stop production for more than 2 months. All the teams are serving the discharge water, affecting the production of raw coal by nearly 50,000 tons. The 80402 working face, which is similar to its geological conditions, draws on this lesson and completes the task of detecting water for three months in advance, creating conditions for stable production and high yield of the mining face.
(3) The water quantity and source of the upper layer water should be judged by various methods, and equipped with drainage equipment suitable for it. When the water is explored on the 80401 working surface, we combine the observation of the self-pressure water discharge and the influence of the change of precipitation on the water output of the borehole according to the contour of the coal seam floor of the upper and the first layer. The supply of surface water, and thus by increasing the amount of water discharge and displacement, so that the speed of drainage greatly exceeds the water seepage speed of the surface, creating conditions for the restoration of production. This judgment was confirmed from later production practices.
(4) It is necessary to strengthen the support within 10 m near the drill site to ensure a safe operating environment; and to install special telephones at or near the drilling and drainage sites for reporting and command.
(5) In order to get rid of the influence of the upper water, for the working face of the mountain, on the one hand, it is necessary to speed up the advancement; on the other hand, it must be drained while producing; in addition, we also build a retaining wall in the tailway to make the water flow to the gob. . For the downhill working face, a small reservoir should be excavated at a distance from each other to facilitate storage and discharge of the gushing water.
(6) It is necessary to investigate the surface conditions according to the in-hole downhole comparison map of the working face of the water surface in advance, and crack the blockage or river diversion according to the actual situation.
(7) Before the drilling, 2 m to 4 m, a water control pipe must be installed to control the water volume. When the water control pipe is long and cannot be installed at one time, it must be installed in sections and wedged. The water control pipe must be fixed firmly to prevent falling off; after draining the water, the valve should be closed in time to prevent leakage of gas; before the drain hole is plunged into the goaf, water should be discharged once every few days to make the upper water as much as possible. Release it to avoid threats to production.
(8) When drilling and drilling, it is found that the coal pressure is soft, the water pressure in the sheet, the pressure or the borehole suddenly increases, and when there is an abnormal phenomenon such as a top drill, the drilling must be stopped, but it cannot be pulled. When the drill pipe is drilled, it is necessary to report it in time and send someone to monitor the water situation. When the situation is critical, evacuate the personnel in the water-threatening area immediately and take measures to deal with it.
(9) In the design of the borehole, the drilled holes shall be arranged on one or several working faces covering the upper layer of the working face, and two drill holes are generally arranged at each location. When judging whether the borehole penetrates the old air, it is determined according to the change of the gas volume, the change of the wind flow at the drill hole, and the sound condition.
(10) The amount of water to be discharged should be carefully observed to change the amount of water, and 2 or 3 times of drilling and dredging should be carried out according to the situation to prevent the smoldering of the coal shovel to cause the illusion of water or water.
(11) When draining the tailgate, special safety measures should be established. On the one hand, a full-time gas inspector should be installed to detect the gas. On the other hand, a gas monitoring and locking facility should be installed to ensure that the gas is safely carried out without exceeding the limit.
(12) When draining, it is necessary to strengthen on-site management, adhere to the management system of the pits and team members, and implement on-site handover. At the same time, we must mobilize all the forces and go all out to serve this work. Establish a patrol inspection system to prevent running, running, dripping and leaking of pipelines and timely maintenance to ensure the smooth completion of the exploration and discharge work.
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