Knowledge of water disaster in the hottest coal mi

2022-08-16
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Knowledge of coal mine flooding and its prevention and control measures (I) coal mine flooding

all floods that affect production and threaten the safety of mining faces or mines, increase the cost of coal per ton and make the mines partially or completely flooded are called coal mine flooding. According to statistics, since the founding of the people's Republic of China, there has been a major accident in which more than 3 people have died in coal mines in China, and the water disaster ranks third; The average death rate per accident is 7.06, second only to gas and fire accidents. For our city, water damage is the main factor that may cause major accidents

the types of mine water disasters are as follows:

1. Surface water disasters:

the water sources are atmospheric precipitation and surface water bodies (rivers, lakes, reservoirs, ditches, pits, etc.). The water source enters the mine through the wellhead, mining caving zone, karst ground collapse or cave, fault zone and the old borehole with poor sealing of coal seam roof and floor, and the improvement of water diversion efficiency

for example, the sudden flood in Northern Fujian in 1998 flooded the coal mine near the river, causing huge economic losses

2. Old gob water disaster

the water source is the ponding of ancient wells, water kilns, waste roadways and goaf. When the mining face approaches or communicates, the old empty water enters the roadway or face, causing an accident. This is the main type of water damage in coal mines in our city

for example, on July 23, 1997, the goaf of a small coal mine in the upper part of Yongding mine was flooded, and 3 people died

3. Pore water damage

the water content of coal measure strata in Longyong Coalfield is weak and medium, but it is obviously replenished by atmospheric precipitation, which shows that the water inflow in seasonal months increases significantly

4. Karst water disaster

there is no limestone in the coal measure strata of Longyong Coalfield, but affected by the structure, it directly interfaces with Qixia limestone, and the karst water enters the mine through the fault, causing water disaster

for example, a construction well in Longyan was seriously affected by karst water, so it had to invest more than 13 million yuan and was forced to dismount

5. Fissure water disaster

the water source is the water of sandstone, conglomerate and other fissure aquifers, which is often recharged by surface water or other aquifers. Through the caving zone, fracture zone, mining roadway, the sandstone water of roof or floor is exposed, or the old borehole with poor hole sealing leads water into the roadway or working face

II. The main provisions of the coal mine safety regulations on water prevention and control in mines

1. Coal mining enterprises should find out the hydrogeological conditions of mining areas and mines, prepare medium and long-term water prevention and control plans and annual water prevention and control plans, and organize their implementation

coal mining enterprises must regularly collect, investigate and check the situation of adjacent coal mines and abandoned old kilns, and mark their mine field location, mining years and ponding on the comparison map of upper and lower works

2. For mines with complex hydrogeological conditions, it is necessary to establish a groundwater dynamic observation system for the main aquifer (section), carry out groundwater dynamic observation, water damage prediction and analysis, and formulate corresponding comprehensive prevention and control measures such as inspection, exploration, prevention, blocking, interception and drainage

3. Coal mining enterprises must conduct a comprehensive inspection of water prevention and control before the rainy season every year

for mines threatened by water in rainy season, water prevention and control measures should be formulated in rainy season, and rescue teams should be organized to reserve sufficient flood control and rescue materials

4. Coal mining enterprises must find out the catchment and leakage of the surface water flow system in the mining area and its vicinity, the drainage capacity and the situation of relevant water conservancy projects, master the local precipitation and the highest flood level data over the years, and establish drainage, waterproof and drainage systems

5. Waterproof coal pillars must be reserved at the boundary of adjacent mines. When the mine is divided by a fault, waterproof coal pillars must be left on both sides of the fault. For mines that have been connected with each other, waterproof walls of sufficient strength must be built at the connected places

the size of the waterproof coal pillar should also give the extruder industry an endless driving force for development. According to the geological structure, hydrogeological conditions, coal seam occurrence conditions, surrounding rock properties, mining methods, rock movement rules and other factors of adjacent mines, it should be specified in the mine design. According to the regulations of mine hydrogeology, when driving in the flooded area or under the ponding area, the minimum vertical distance between the roadway and the water body shall not be less than 10 times the height of the roadway, and the size of the waterproof coal pillar shall not be less than the sum of the maximum height of the water conducting fracture zone and the thickness of the protective layer, which shall generally be greater than 30 times the mining thickness

6. The mine must do a good job in water hazard analysis and prediction, and adhere to the principle of water exploration and drainage, which is "if there is doubt, it must be explored first, and then excavation"

before water exploration or excavation in areas close to ponding or before draining ponding in flooded shafts and roadways, water exploration and drainage design must be prepared, and safety measures such as preventing gas and other harmful gas hazards must be taken

the lead distance of the layout of the water exploration hole should be specified in the water exploration and drainage design according to the height of the water head, the thickness and hardness of the coal (rock) layer, and safety measures

correctly determine the water exploration line. The water exploration line is the starting point of water exploration. The water exploration line should be determined according to the location, scope, hydrogeological conditions and reliability of data of the ponding area, as well as the cost area in which the goaf saves customers 20% - 40% on average, and the damage of the roadway by the mine pressure

II. Omens before water seepage in the mine

generally speaking, there are several omens before water seepage in the mine:

(1) sweating. Under the action of self pressure, the water in the ponding area accumulates into many drops on the coal and rock wall of the mining face through the coal and rock fissures, which is called sweating. When encountering low-temperature coal, the water in the underground air may sometimes gather into many water droplets. The way to distinguish between true and false sweating is to carefully observe whether the newly exposed coal wall is wet. If it is wet, it is a sign of water permeability

(2) hanging red. The mine water contains iron oxide. When it penetrates into the coal and rock surface of the mining face through the coal and rock fissures, it will show dark red rust. This phenomenon is called hanging red. Hanging red is a kind of water signal

(3) water cry. When the high-pressure water in the aquifer or ponding area is squeezed into the cracks of the coal wall, it will hiss when rubbing with the two walls, which indicates that the mining face is very close to the ponding area or other water sources. If the coal roadway is excavated, the water seepage is about to occur. At this time, an alarm must be issued immediately and all personnel threatened by water must be evacuated

(4) the air becomes cold. When the mining face is close to the ponding area, the air temperature will drop, and the coal wall will be cool. People will feel cool and gloomy as soon as they enter the working face; However, it should be noted that the temperature of underground water in mines greatly affected by geothermal is on the high side. When the mining face is close to the ponding area, the temperature will rise instead

(5) fog appears. When the temperature of the mining face is high, the water seeping from the coal wall will be evaporated and form fog

(6) the roof water spraying is increased

(7) the top plate presses and the bottom plate bulges

(8) the water is muddy and smelly

(9) the harmful gas in the mining face increases, and the ponding area emits harmful gases such as gas, carbon dioxide and hydrogen sulfide

(10) water seepage occurs in cracks. If the effluent is clean, it is far away from the ponding area; If it is muddy, it is close to the ponding area

III. Prevention and control measures of mine water disaster

(I) prevention measures of mine water disaster

prevention measures of mine water disaster can be summarized as prevention, drainage, detection, drainage, drainage, interception and blocking

waterproof: Waterproof facilities and measures above and below the well

drainage: underground drainage facilities and drainage capacity

exploration: water exploration in shaft and roadway

drainage: that is, drainage of accumulated water and suspicious water sources in the old goaf, or drainage of roof water in advance

drainage: that is, drainage and decompression or drainage of harmful aquifers

interception: that is, various waterproof coal pillars are reserved to block harmful water sources

plugging: that is, grouting to block the water inlet, or strengthening the fracture zone, filling the dissolved aquifer, and strengthening the floor

(II) pay attention to water exploration and drainage

1. How to cooperate with water exploration and tunneling

(1) cross water exploration in double roadway tunneling. When driving up the mountain, if there is a ponding area above, the three sides of the roadway are threatened by water. Generally, double roadway driving and cross water exploration are adopted. A connecting lane is dug every 50m between the two lanes as a safe refuge. When exploring water in one roadway, the other roadway is excavated, and the water exploration and tunneling of the two roadways are carried out alternately until the roadway reaches the design end point

(2) advance water exploration of single roadway in double roadway excavation. When tunneling in inclined coal seams, the way of advance water exploration in the upper roadway is generally used

(3) the drift and uphill cooperate to detect water: in the same coal seam, the upper part is excavated uphill. At this time, the drift should be explored first, and then the hill should be excavated, so as to avoid the danger of uphill excavation and reduce the workload of uphill excavation

(4) isolated water detection. Under the conditions of large water volume, strong water pressure, soft coal seams and joint development, direct water detection is very unsafe, and isolation is required for water detection. For example, when excavating the stone gate, the ponding is detected in advance in the stone gate; Or build a water barrier at the head of roadway excavation and probe water outside the wall; In addition, when the distance between adjacent coal seams is greater than 20m, the method of drilling holes in the isolation layer can also be used to detect and release the old goaf water in another coal seam

2. What safety measures should be taken during the excavation of water exploration roadway

(1) the excavation section of water exploration roadway should not be too large to reduce the pressure area. At the same time, there should be two emergency exits for personnel evacuation in case of ventilation, running water and accidents. Generally, double lane excavation should be carried out, and safety refuge chambers should be excavated between crossings when necessary

(2) the slope of the excavation roadway shall not fluctuate to avoid the low water formula: it cannot flow out, and the construction personnel are in danger of being blocked

(3) when the tunneling face encounters signs of water seepage, it must stop moving forward, reinforce the support, withdraw personnel to a safe place, and report to the personnel on duty in the control room; The leader on duty shall organize relevant personnel to the site to check and analyze the situation. If the situation is urgent, an alarm must be issued immediately to evacuate all personnel at the place threatened by water

(4) when the water hazard in the uphill direction has not been eliminated or the water is being explored, in order to ensure the safety of the staff going down the mountain, their work should be suspended until the water hazard threat is eliminated

(5) if the tunneling face that has explored the old gob and has drained water cannot be dug through with the old gob immediately and tunneling is carried out after a few days, 2-3 inspection holes should be re drilled to prevent the original borehole from collapsing and blocking and re ponding, and the tunneling must not be rash

(6) the water exploration roadway must strictly grasp the roadway excavation direction and excavate along the center line of the water exploration hole, so as not to cause the lead distance and side distance to reduce and encounter the old air seepage. If it must deviate due to geological changes, supplementary drilling or other measures should be taken to remedy it

(7) most of the ponding has been released. During excavation, attention should also be paid to the ponding in the old goaf of blind roadway or the isolated ponding area formed by the isolation of faults

(8) reasonably select the blasting method of roadway excavation. Under the close cover of the water probe hole, and when maintaining the design lead distance and side distance, the methods of drilling more holes, charging less, and blasting less can be adopted to maintain the compressive strength of the coal

(9) strictly implement the three no charge system: do not charge when there are signs of water coming out of the blasthole or the digging head, the lead distance is not enough or deviates from the direction of water exploration, the support of the digging head is not firm or the empty roof exceeds the regulations

(10) in order to prevent accidents caused by re ponding after exploration and drainage, all personnel should be evacuated to the liaison crossing or lower drift when driving the old air blasting in the uphill roadway or the inclined crosscut with large slope