(1) Ground drainage

Ground drainage is an important measure to prevent or reduce atmospheric precipitation and surface water flooding, and is the first line of defense to ensure mine safety. Especially for mines with atmospheric precipitation and surface water as the main water-filling source, the groundwater prevention and drainage work must be carried out frequently. Especially before the rainy season, it is necessary to do all kinds of water prevention and drainage work.

The ground prevention and drainage measures mainly include filling channels, removing accumulated water, excavating flood ditches, embankment flood control, rebuilding river bottoms and river diversions, etc., must be reasonably selected according to topography, hydrology and meteorological conditions, and sometimes several measures Comprehensive use for better results.

(2) Downhole prevention and control water

1. Identify the water source

The groundwater source is invisible. Only through surveying, the accumulated water in the ancient wells and goafs, as well as the distribution of main aquifers, water-filled faults and fissures, are determined to define the water line, water line and warning line of the mine.

2. Exploring water

1) Water exploration

(1) The principle of “doubt must be explored, first explored and then excavated” must be implemented in underground production.

(2) All the following situations must stop the excavation and conduct water exploration:

1 The heading face is close to the cave, aquifer (flowing sand layer, alluvium, aquifer of various confined water, water-bearing fault or fault connected with a large amount of water on the ground);

2 The heading face is close to the flooded roadway or a small kiln with old water and old air;

â‘¢ upper water, extractive work performed in the lower layer, the vertical distance between the two layers is less than 40 times the mining coal face mining height or less than 10 times the height of the Tunneling;

4 When excavating in the excavation and excavation area, the excavation length reaches the allowable excavation length;

5 signs of water found in the mining face;

6 When the mining face is close to all kinds of waterproof coal pillars;

7 close to the fault fracture zone that may be connected to rivers, lakes, reservoirs, reservoirs, wells, etc.;

8 when approaching a grouting area with water or mud;

9 close to other possible watershed areas.

(3) Pay attention to the following questions before water exploration:

1 Strengthen the support close to the water surface to prevent high pressure water from rushing the coal wall and the support;

2 Check the drainage system, according to the estimated amount of water to determine whether to increase the drainage capacity, clean the ditch, water tank to make it smooth and buffering;

3 When the water pressure is large, the water inlet hole should be provided with a casing to install the water valve to control the water discharge. In particularly dangerous areas, a solid location should be selected to build the sluice wall;

4 The deepwater work place should have a telephone to be able to contact the dispatch room and the central pump room in time.

(4) Precautions when exploring water:

1 The location of the water exploration should ensure contact with the work place in the adjacent area. Once the water is discharged, the staff of the water threat area should be notified immediately to the safe place.

2 When drilling, it is necessary to observe the condition of the hole at all times, and find that the coal seam is loose. When the drill pipe advances suddenly and feels that the water flowing out of the drill pipe exceeds the water supply amount, special attention must be paid. These are close or drilled. Signs of water locations. In this case, stop drilling immediately and check. If the water in the hole is large and the spray is far away, the drill pipe must be fixed immediately, and the steaming work surface, such as the reinforcing coal wall and the top plate, should be tightened.

3 The water surface should be inspected frequently for gas and other harmful gases. When the gas content reaches 1%, the drilling must be stopped; when it reaches 1.5%, it must be stopped to reduce it to less than 1% before the machine can be started.

2) Water release (drying)

(1) To dispose of old air, there are several methods:

1 directly release water. When the water pressure is not large enough to exceed the mine drainage capacity, the water can be directly drained by using the water drilling hole.

2 plug first and then put. When the old water is related to the cave water or other huge water sources, the reserves of moving water are very large. If the water is not finished or it is impossible to discharge, the water outlet should be blocked first, and then the water should be discharged.

(2) Discharge aquifer water. It includes ground draining water, using hydrophobic underground tunnels and so on. The former is suitable for aquifers with shallow burial and good permeability. The latter applies when the water source has been identified and the amount of gush is budgeted.

(3) Precautions when discharging water:

1 The amount of water must be estimated before the water is discharged, and the amount of water discharged and the flow of the water eye should be controlled according to the mine drainage capacity and the water tank capacity.

2 Always observe the change of water volume in the borehole. When the water is small or no water, it should be drilled repeatedly to the original hole depth or exceed the original hole depth to prevent the borehole from being blocked. , causing the illusion of draining water and avoiding accidents during tunneling.

3 During the process of discharging water, the content of gas and other harmful gases released from the holes should be checked frequently to take measures.

3. Leave a waterproof coal pillar

The purpose of leaving the waterproof coal pillar is to cut off the passage of various water sources above and below the well. To determine the size of the coal pillar, various factors such as the pressure of the water source, the flow rate, and the occurrence of the coal seam must be taken into account.

Water-proof isolation coal pillars are mainly divided into well-separated coal pillars, fault-waterproof coal pillars, coal pillars between flooded roadways, and coal pillars that are reserved for flooding and drifting sand.

4. Water interception and water shutoff

(1) Water interception. In order to prevent the water in the local area from falling into other areas, it is necessary to install a water gate or a sluice wall in the waterway.

(2) Water blocking. Grouting and plugging water is to crush the specially prepared slurry through the pipeline to the ground fissures or holes, and to achieve the purpose of isolating the water source after being condensed and solidified. In the grouting and water blocking project, it is very important to choose the grouting material reasonably. It is related to the grouting process duration, cost and grouting effect. At present, grouting materials applied at home and abroad are various and can be easily divided into two categories: silicates and chemical slurries.

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