Technical measures for prevention and control of water in coal mine face

1. Overview of the work surface

The 11071 working face is located in the second section of the upper part of the east wing of the 11 mining area. The working surface of the 11071 corresponds to the ground and the iron village, and the ground elevation is +112m-+119m. The 11071 working face starts from the Shangshan coal pillar in the 11 mining area, east to the iron Lizheng fault, the upper part is the 11031 working face goaf, and the lower part is the 11111 working face goaf, which is the “island” coal mining face. The 11071 wind tunnel has a length of 1312m, the 11071 middle lane has a length of 1541m, and the 11071 machine lane has a length of 1568m. The upper and lower parts are jointly mined at the cut 1 point to form a large working face. The average length of the lower cut is 162m, the average length of the upper cut is 165m, and the average length of the combined working face is 327m. The wind, middle, machineway and cut-out are all arranged along the top of the 2nd coal seam. The west roadway of the working face is 104°. The central adjustment position is 89° to the east roadway, the elevation of the roof of the 11071 wind tunnel is -358.530m~-341.740m, and the maximum elevation difference is 16.79m; the elevation of the top roof of the 11071 is -397.812m~-373.125m, the maximum elevation difference It is 24.687m; the elevation of the top plate of the 11071 machine is -433.809m ~ -406.325m, and the maximum elevation difference is 27.484m. The coal mining area of ​​the working face is 418,545.64 m2, the coal seam dip is 12° on average, and the average coal thickness is 3.98 m. The geological reserves of the 2 1 coal seam are calculated to be 2,282,200 tons. The coal mining method is to go to the longwall and retreat to collect full thickness comprehensive mechanized coal mining.

2. Geological structure

The coal seam of 11071 working face is relatively stable and the geological conditions are relatively simple. The coal seam strikes 81°-107°, and the coal seam inclination angle is 10°30′～14°. The wind, medium and machineway exposed in this working face is thicker in the western coal seam, the coal seam in the middle and east is thinner, the upper coal seam is thicker overall, the lower coal seam is thinner overall, and the eastern structure of the 11071 working face is affected, so that the top and bottom of the coal seam are different. The fluctuation of the coal seam is thinner (<2m) in the 100m west of the lower cut.

The east of the 11071 working face is the iron Lizheng fault, with a strike angle of 116°-296°, a dip angle of 67°, and a drop of 23 to 26 m. The upper cut eye is about 30 m eastward for the FS7 inferred fault, with a fault drop of 0 to 11 m and a dip angle of 65°.

3. Main water source

From the exposure of the 11071 working face wind, middle and machineway excavation, the hydrogeological conditions are relatively simple, affecting the large aquifer in the working face, mainly the coal seam roof B4 sandstone fissure water, old space product Water and floor Cambrian limestone water. (1) According to the exploration drilling data of 0143, 01310, 0116, the direct water-filled aquifer of the second coal seam roof is sandstone with a thickness of 28.12 meters, which is the direct top of the 2 coal seam, which belongs to the weak aquifer, and there is dripping water during the excavation process. Phenomenon, it is expected that the amount of water will increase as the roof falls during the recovery period.

(2) 11031 working face old empty water: In the process of tunneling of 11071 wind tunnel, it has been explored in 9 stages. The total amount of water discharged is about 4100m3. Currently, it is relatively low-lying between 05F10 and 05F12. There is still water seepage in the empty area.

(3) Floor ash karst fissure aquifer: The Cambrian dolomitic aquifer is about 70m above the base of the 2nd coal seam, and the maximum exposed thickness of the ground exploration bore is 145.6m. Under the condition of no hydrophobic pressure reduction and floor reinforcement, The Cambrian limestone water easily breaks through the water in the water layer of the coal seam floor. The roadway measured the Cambrian limestone water pressure 1.6MPa, water temperature 36 °C.

4. Water inrush coefficient and water inflow forecast

According to the roof watering situation in some sections during the excavation, it is expected that the 11071 working face will fall with the roof as the roof falls, and the maximum water inflow is expected to be 5m3/h.

According to the existing hydrological data of the mine, it is expected that during the mining process, as the area of ​​the goaf increases and the depth of the damage of the floor increases, the cold grey water may enter the working face through the water-conducting fissure of the floor to cause water inrush. According to the hydrogeological analysis of the working face, after grouting reinforcement through the coal seam floor, after the floor transformation rate reaches 100%, the thickness of the aquifer is guaranteed to be above 70 meters, and the water pressure of the Cambrian limestone aquifer is 1.6 MPa maximum. Its water inrush coefficient is calculated as:

Ts=P/M=1.6/70=0.023

Using the empirical comparison method, the relevant parameters are as follows:

The current surface of the 11151 working face is 150 m3/h. The Cambrian limestone aquifer is about 70m away from the bottom of the 2nd coal seam. The current water pressure is 1.9Mpa. The water inrush coefficient is calculated as:

Ts=P/M=1.9/70=0.027

Using the empirical comparison formula to calculate the normal water inflow of the 11071 working face using the relationship between water inrush and water inrush coefficient:

Q071=Q151/Ts151×Ts071=150/0.027×0.023=127.8m3/h

According to the recent observation data of total mine water inflow and water level decline rate, the maximum water inflow in this area is calculated according to 1.5 times of normal water inflow:

127.8×1.5=191.7m3/h

After calculation, the normal water inflow of the top and bottom plates of the 11071 working face is 127.8m3/h, and the maximum water inflow is 191.7m3/h.

Second, the leadership

In order to ensure the normal operation of the water prevention and control work of the 11071 working face, and to ensure the quality and effect of the construction of the prevention and control water project, the 11071 working face water prevention leading group was established.

Team leader: XXXX

Deputy leader: XXXX

Members: Other members of the Security Committee and all units

The Office of the Water Prevention Leading Group has an office, and XX is the Director of the Office.

The Water Prevention and Control Leading Group shall hold regular meetings on water prevention and control work to solve problems in the work and arrange and implement various tasks.

The Office of Water Prevention and Control is responsible for the preparation of water prevention and engineering design, organizes and implements various work contents, and is responsible for supervising and inspecting the quality of construction and acceptance of the project; observing the changes in water volume, water pressure and water level at various locations above and below the working well, collecting and collating Kind of information, found abnormalities immediately reported to the mine leaders and dispatching room.

The geodesic, electromechanical and production departments must constantly prevent and control the water project site, keep abreast of the progress of the water control project, and implement and coordinate the problems in the work.

The dispatching room is responsible for coordinating the production and transportation of underground mines, ensuring the smooth flow of water control equipment and materials.

Finance, Business Section must ensure that funds, material supply, can not take place due to financial, material supply does not affect the timely progress in combating water projects.

The leaders of the leading group must fulfill their duties in a highly responsible manner, and according to their respective division of labor, conscientiously coordinate and deal with various problems encountered in the construction of water prevention and control projects. When an abnormal situation occurs in the underground, the leading team members must be assigned to the underground site in three shifts to ensure safe production.

Third, the status of mine drainage

At present, there are 3 main drainage pump rooms at the mine-550m level. The effective total volume of the three pump houses is 13225.6m3, 18 drainage pumps, 8 working pumps, 6 standby pumps, 4 maintenance pumps, and maximum drainage. Capacity 4650.7m3/h; 1# pump room is equipped with 6 PJ150-65×11 pumps (supporting motor 900Kw, head 713.2m, single pump displacement 300m3/h), 3趟Ф273mm drainage pipe, water tank volume 4357m3, the maximum drainage capacity is 1220.7m3/h; 2# pump room is equipped with 4 PJ150-65×11 type pumps (supporting motor 900Kw, head 713.2m, single pump displacement 300m3/h), 2趟Ф325mm drainage pipe, water The warehouse volume is 4551m3, the maximum drainage capacity is 1000.2m3/h; the 3# pump room is equipped with 8 PJ200-8 type drainage pumps (supporting motor 1250Kw, head 742.3m, single pump displacement 420m3/h), water tank volume 4317.6m3, The maximum displacement is 2429.8m3/h.

Fourth, the work surface water prevention measures

1, hydrophobic pressure reduction

Using the water discharge hole at the level of -550 horizontally under the working face, the hydrophobic pressure reduction is continued during the recovery period to minimize the water pressure of the bottom Cambrian limestone aquifer.

2. Strengthen hydrological real-time observation

The hydrological dynamics of the floor limestone aquifer will continue to be observed by using the 01613, 0149 hydrological observation holes and the water supply holes in the 22nd underground drilling site constructed on the ground of the 11 mining area where the working face is located, and the prevention and control of the working face during the mining period The decision to make water work provides the basis.

3. Strengthen the exploration and discharge of old air water

In the process of tunneling in the 11071 wind tunnel, according to the principle of “long exploration and short verification”, the exploration of the old air has been carried out in 9 stages. The total drainage water is about 4100m3, and the upper and lower water in the excavation process is removed. The threat is that there are 2 holes in the construction of the low-lying area on the 11071 wind tunnel to observe the water conditions in the old air area. The water inflow in the 11031 goaf is about 0.3m3/h, and the coal seam is normally infiltrated into the 11071 wind tunnel. In order to further ensure the safety of mining, the drilling of the low-lying area of ​​the upper old empty area is verified by the drilling rig in the 11071 wind tunnel before the mining, and the re-exploration and verification are carried out to ensure the safety of the mining.

4, the floor grouting transformation

According to the principle of “circle edging, full coverage, and same horizon”, all the Cambrian limestone aquifers on the working face are grouted and rebuilt, and the final pore horizon is the upper boundary of the Cambrian limestone aquifer. The distance is 20m, and the intricate drilling area of ​​the object (drilling) probe area is arranged and the construction inspection hole is designed to ensure the working surface transformation rate is 100%.

5, water inrush risk assessment

According to the “Regulations on Prevention and Control of Coal Mines”, the risk of water inrush from the working face shall be evaluated before mining. The water conduction factors such as the water guiding channel, the water source and the thickness of the water-repellent layer of the floor are analyzed. The water inrush coefficient method is used to analyze the floor limestone aquifer affecting the working face, and it is considered that the 300m floor is strengthened before the working face is secured. Under the premise of the distance, there is a small possibility that the floor of the working surface will be in danger of water inrush.

6. Working surface drainage scheme

The normal water inflow of the 11071 working face is expected to be 132.8m3/h, and the maximum water inflow is calculated as 196.7m3/h according to 1.5 times of the normal water inflow. The main pressure of the water in the working face is 11071. According to the change of the coal seam production and the roadway fluctuation of the 11071 roadway, the drainage ditch and the drainage pipe are used for drainage during the mining. According to the requirements of the coal company, the maximum drainage capacity is not less than 500m3. /h.

(1) Ditch drainage: The slope of the 11071 machineway does not change much. From the machine entrance to the 17J9 measurement point and between the 17J15 measurement point and the cut-eye, the floor of the roadway is lowered from the inside to the outside, which can ensure the self-flow discharge. Therefore, 300mm × 300mm ditch (pitched iron sink) can be used for drainage; between 17J14 measuring point and 17J15 measuring point, between the ditch and 17J9 to 17J10 measuring point, water can not be self-exiting section, temporary air pump can be installed in low-lying area Or submersible pump for partition drainage.

(2) Pipeline drainage: From the temporary pumping pit in the middle of the transfer machine (1 pump to 1 pipe), lay a 趟Ф219mm and a 325mm pipe to the 11071 machineway return airway. At the same time, the No. 1 temporary drainage pump socket (built-in 5 22kw drainage pump) is set up in the low-lying area of ​​the 400m roadway (the specific location of the site), and the mining surface is pushed forward with the working face. When the pumping pit is 20m, a temporary pumping pit No. 2 is added at a distance of 300-350m from the outside (west), and so on, and the working surface is always kept at least one available drainage pump socket. A permanent pumping pit (with sedimentation tank) is installed at the head of the two belt conveyors of the 11071 machine, and five 22KW submersible pumps are installed.

(3) Specific requirements:

1 Drainage pump socket: No.1 drainage pump socket is located at 11071 cut-off outward (west) 400m, under the belt frame construction, the drainage pump socket specifications are net length 4m, net width 1.8m, net depth 1.2m. The bottom surface and the excavation part are poured with concrete, and the thickness of the pouring is 0.15 m. With the work surface mining advancement, when the special west head is 20m away from the No. 1 pump socket, the No. 2 pump socket is added at a distance of 300-350m from the west (west), and so on, the No. 3 pump socket is set.

2 permanent pump socket: located at the 2 belt heads, the specific location of the site calibration. The pump socket is divided into a sediment portion and a drain portion. Both specifications are net length 2m, net width 1.8m, and net depth 1.2m. The bottom surface and the excavation part are poured with concrete, and the thickness of the pouring is 0.15 m. When the working surface of the working face is 30-50m away from the permanent pumping pit, there are 7 sets of 22kw submersible pumps (80m3/h displacement) at the low point of the working face under the working face. The maximum drainage capacity is not lower than the working face. 500m3/h, until the running surface water can flow to the yard ditch, and then every 300-350m, add a temporary drainage pump socket, set up 5 submersible pumps in the pump socket, three for use, two for standby; This type of push until the end of the work surface.

3 Drainage pipeline: Lay a 219mm pipeline from the temporary pumping pit in the middle of the transfer machine and a 325mm to 11071 machine return airway measure. The drainage pipeline will have the corresponding number of pumps in each pump pit. Three-way (changing 108mm interface), and requires the angle between the three-way interface and the water flow direction is not more than 45°.

4 Drainage pump: Two 22KW submersible pumps (displacement 80m3/h) are arranged in the temporary pumping hole in the middle of the transfer machine, one for normal use and one for standby (hot standby); five 22KW for installation in the temporary drainage pump socket of the machineway Submersible pump (displacement 80m3/h), 3 sets are used normally, 2 sets are reserved; 5 sets of 22kw submersible pumps are installed in the permanent drainage pump socket of the machineway, 3 sets are used normally and 2 sets are reserved.

(4) Calculation of drainage capacity of working face

During the mining face mining, a 300mm × 300mm section gutter and a 219mm and Ф 325mm drainage pipe are used for drainage at the same time.

Drainage capacity: Q=3600×k×V×S

Where: k is the unevenness coefficient V is the water flow velocity S is the water cross section

Ditch: k=0.7 V=0.64m/s S=0.3×0.3=0.09m2

Find: Q gutter = 136m3 / h

Pipeline: k=1.0 V=2m/s S219=3.14×(0.219÷2)2=0.037m2

S325=3.14×(0.325÷2)2=0.083m2

Obtained: Q219=266m3/h Q325=298m3/h Q tube=Q219+Q325=564m3/h

In addition: there are 7 effective drainage pumps for the 11071 working face (single rated drainage capacity 80m3/h).

Find: Q pump = 80 × 7 = 560m3 / h Q tube > Q pump

Therefore, the actual drainage capacity of the working face is: 7×80=560m3/h

In summary, the maximum drainage capacity of the 11071 working face is not less than 500m3/h.

Drainage route: working surface drainage system→11071 machineway return air measure roadway→11 return wind uphill→east belt roadway→ main stone gate→hole bottom water tank→ground

The amount of water in the working face and the middle road is relatively small. The maximum water inflow during the mining process is about 5m3/h. The wind (electric) pump is combined with the drainage pipe and the ditch for drainage.

Drainage route: wind (middle) lane drainage system → 11071 (wind in the wind) return air measure lane → 11 return wind uphill → east belt lane → main stone gate → bottom hole water tank → ground

7, anti-drainage measures

(1) Before mining, the drainage capacity of the working face must be checked and accepted according to the design of the drainage scheme. If the requirements are not met, the mining is not allowed to be recovered. The advancement of the grouting of the working surface is not less than 300m.

(2) According to the basic principle of “dual system, same capacity, hot standby, anti-failure”, the drainage system is equipped, and the anti-drainage equipment and facilities are frequently overhauled, inspected and maintained to ensure timely discharge after water inrush.

(3) Improve water and drainage equipment, strengthen the construction of water prevention and control teams, and ensure that the drainage equipment must be in good condition and updated in a timely manner.

(4) Strictly follow the "Safety Regulations for Coal Mines", "Regulations on Prevention and Control of Coal Mines" and the annual water control plan, focusing on the prevention and control of Cambrian limestone water, long-term hydrogeological conditions exploration and short-term working face mining prevention and control technology Combine.

(5), 11071 working face using transient electromagnetic detection to find out the water content of the confined aquifer in the coal seam floor and the thickness of the aquifer, providing a reliable basis for safe production and water prevention.

(6) According to the results of geophysical exploration, the drilling verification and treatment work is carried out underground. Firstly, the full-coverage floor reinforcement design is carried out for the work. During the construction process, the geophysical low-resistance anomaly area and the large water output area are drilled and verified. Grouting reinforcement measures to control and strengthen the weak zone of the water-repellent layer of the floor or the potential water inrush channel, so as to achieve the purpose of preventing water inrush from the floor.

(7), 11 mining area - 550 horizontally arranged hydrophobic holes continue to carry out hydrophobic pressure reduction, to minimize and stabilize the water pressure in the area to be harvested.

(8) Continue to strengthen the water dynamic observation and water damage prediction analysis of the main Cambrian limestone aquifer.

(9) Working surface drainage ditch, sedimentation tank and temporary water storage should be cleaned regularly to prevent siltation, and the main drainage pipeline should be regularly checked. Once the siltation is carried out, the drainage system will be smoothed.

(10) Do a good job in hole verification and safety technology evaluation after the completion of the water control project, summarize the experience of water control, and provide a basis for future water control.

(11) Formulate a special emergency rescue plan for water disasters on the working face. When the surface is discharged, it is necessary to stop the work and evacuate the personnel and take effective measures to deal with them.

(12) If the water is discharged from the upper part and the middle part, in order to prevent the flushing of the working surface, immediately organize the water from the water outlet point to the rear side of the bracket, and strengthen the mining surface to prevent the roof from falling. The drainage personnel at the transfer machine found that there was a phenomenon of coal rushing. In a controlled state, the coal was cleaned in time to ensure the normal operation of the pump.

(13) When the power supply is faulty, the pipeline is blocked, and the drainage cannot be guaranteed, the operation must be stopped and the mine dispatching room must be reported. The production can be resumed when the drainage system is normal.

(14) If there is any abnormality in the working face or other places, report to the dispatching room immediately and stop the operation and take effective measures.

(15) Disaster avoidance route

The upper part of the flood point or the evacuation route that can pass through the water outlet: 11071 wind (middle) lane → 11071 wind (middle) lane return air measure lane → 11 mining area return wind uphill → Dongfeng well → ground.

The lower part of the flood point cannot pass the evacuation route of the personnel at the water outlet: 11071 machine lane → 11071 machine lane return air measure roadway → 11 mining area return wind up the mountain → Dongfeng well → ground.

V. Observation plan for water inflow during initial mining of working face

During the recovery period of the 11071 working face, especially during the initial pressure of the roof, the special personnel were arranged to perform hydrological observation on the working face in three shifts. The abnormal or sudden water inrush was immediately stopped, and the dispatching room and relevant leaders were reported in time.

During the initial mining period, observation points are set at the tail of the machine-passing machine and the wind tunnel, and the special surveying department assigns a special person to observe, and each shift is observed once and recorded in detail. The scope of observation includes goaf, face wind, machineway and face cut.

During the observation, attention should be paid to the change of the coal seam at the working face, the condition of the top and bottom of the coal seam, the magnitude of the mine pressure, the change of the water inflow, etc., and the abnormality is immediately reported to the dispatching room.

The geodesy department is responsible for collecting and arranging observation data, and compiling staged work analysis reports and observation work summary reports in a timely manner.

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