Outburst prevention and rock burst prevention meas

Outburst prevention and rock burst prevention measures at the working face

according to the mine arrangement, our team is about to turn to 7433 material road and East chute sub road construction. At present, 7433 material road has been constructed to 19m before m1# point, and the roadway elevation is about -848m. Our team continues to construct along the top according to the original orientation of 60168, and the total length of the roadway is about 1580m; The East chute sub road is constructed to 33m in front of J1 point, and the roadway elevation is about -901m. Continue to follow the bottom construction according to the original orientation of 60168. The total length of the roadway is 1490m. Our mine has a strong rockburst tendency danger below the mining depth of -785m, and coal and gas outburst may occur, which seriously threatens the safety production of the coal mine. In order to prevent outburst and rockburst, this measure is formulated in combination with the production practice experience of prevention and control in our mine

schematic diagram of plane position:

I. geological conditions:

1. 7433 material road and East chute road are excavated along 7# coal, mainly in the middle of Permian Shanxi formation, and the roadway slope is about 0 ~ 5

2. Geological structure: the geological structure is relatively complex

3. Coal seams have the tendency of spontaneous combustion, and coal dust has a strong explosion risk

II. Hydrological conditions:

the hydrogeological conditions of the project are simple, and there is no drenching. The estimated normal water inflow is 2 m/h. Maximum water inflow 10m/h. The accumulated water in 7431 drainage tunnel is about 200 m? It has a certain impact on this working face

III. other conditions affecting tunneling

1. Mine gas grade: low gas mine

2. Ground temperature: original rock temperature 40, air temperature 27 C

7433 layout of impact relief holes for penetration prevention of Dongcai material channel and dongchuzi

I. there are three types of dynamic phenomena occurring in roadway excavation: protrusion, extrusion and dumping. At present, this situation has not been seen. With the deepening of the mining depth of Kongzhuang Coal Mine, there may be the danger of coal and gas outburst during the coal roadway excavation. In view of this, it is necessary to adopt "four in one" comprehensive gas control measures. See the following steps:

Step 1: predict the outburst risk by drilling holes before tunneling, and judge whether it is a outburst dangerous working face

step 2: if the prediction index exceeds the standard, preventive measures should be taken

the third step is to construct the effect inspection hole after taking measures to test the effect of prevention and control measures

step 4: after the effect inspection is qualified, take corresponding safety protection measures before continuing the operation

II. Tunnel construction pressure relief hole process

the tunnel pressure relief hole process is: in the morning shift of each round shift, use the German turmag Tenma FIV gas hand-held drill to drill five holes forward, each of which is 15m deep, and the drill bit diameter is 50mm. After each round shift roadway is excavated for 10m, the pressure relief hole will have a lead distance of at least 5m. The outburst risk prediction is carried out in the roadway head-on, and the outburst prevention measures of the discharge hole should be adopted regardless of whether the index exceeds the limit

precautions for using turmag tengma FIV pneumatic hand-held drill:

1). The compressed air pressure must be controlled at 0.4 ~ 0.6mp (about 4 ~ 6kg). When the maximum allowable air pressure exceeds 6kg, the governor will be rapidly worn, the bearing grease will be lost, and the drill will be damaged due to overload

2). Before connecting the compressed air pipe to the drilling rig, the water and sundries in the pipe should be discharged, and the pipe joint should be wiped dry to prevent dirt from entering and damaging the drilling rig

3). Before the operation of each shift, disassemble the air inlet pipe and the air inlet switch connector, and inject about 2 cubic centimeters of lubricating oil (about the amount of a mineral water bottle cap) from the air inlet

4). Do not use diesel or kerosene to soak the drill, because the lubricating grease will be washed away, resulting in rapid wear of bearing gears

5). Do not use levers and other tools to try to increase the driving force of the drill, which will cause the plastic shell to deform and be worn by gears

6). Before stopping each shift, the drill should idle for 1 ~ 2 minutes to discharge water and pulverized coal, then disassemble the air inlet pipe, inject about 2 cubic centimeters of lubricating oil into the wire drawing fixture from the air inlet, reconnect the air duct, and idle for 30 seconds to prevent parts from blocking

7). Do not use other types of drilling machine parts and accessories to avoid affecting efficiency and service life

8). After each use, the drill pipe should be wiped dry of water and dust, and the part touching the ball should be sprayed with strong derusting lubricating oil to prevent the ball touching and spring from rusting or being blocked by dust, resulting in inability to move

9). Special tools are needed to disassemble the drill, especially the internal aluminum alloy body. Do not try to disassemble and repair by yourself. The damaged shell cannot be repaired and can only be scrapped

10). In case of obvious reduction in working efficiency, slow down and abnormalities (such as internal abnormal sound), the operation of the drilling rig should be stopped and maintenance should be contacted

11). Before starting the drill, pay attention to the surrounding environment, remove the obstacles in the area, and avoid any possible harm to the operator

12). During the drilling process, make sure that the operator holds the equipment safely and securely. The operator holds the drill tightly with both hands. When adjusting the drill, do not endanger others due to touching the switch by mistake

13). Before leaving the drilling rig, turn off the compressed air source and ensure that unauthorized people do not start the machine at will

14). Don't be too hasty and exert too much force in the drilling process. Pay attention to constantly pulling the drill pipe back and forth to increase the chip removal and drilling effect

15). The coal body that is too wet, soft and contains stress may have the condition of maintaining the drill. When the drill tool is locked, don't pull it out hard to loosen it. First loosen the latch connection between the drill pipe and the drill tool joint, unload the drill rig, and the excess oil flows back to the oil tank through the differential pressure relief valve. Put a wrench or special tool on the square joint of the drill pipe, and rotate in the opposite direction, The whole string of drill pipe connectors can be loosened

7433 prevention and control measures of rockburst in Dongcai material road and dongchuzi road

rockburst is one of the major natural disasters threatening coal mine safety production. In order to strengthen the prevention and control of rockburst and ensure safe production, the measures for the prevention and control of rockburst in 7433 working face are specially formulated as follows

the basic procedure of rockburst prevention and control: identification of rockburst tendency → taking preventive measures → prediction and prediction of rockburst risk → judgment of rockburst risk → implementation of hazard relief measures → verification of hazard relief effect. The flow chart is as follows:

first, the identification of impact tendency

after the China University of mining and technology "mining safety evaluation and rock burst prevention measures for 7433 fully mechanized top coal caving face in Kongzhuang Coal Mine" (January 2011), the measurement result is that the coal seam mined in 7433 face belongs to strong impact coal seam

II. Preventive measures

same as gas outburst prevention and control, pressure relief holes shall be drilled

III. prediction and prediction of impact risk

1. The drilling cuttings method is used for prediction and prediction. The erosion prevention personnel of the erosion prevention department guide the construction unit's personnel to drill on site to monitor the amount of pulverized coal, and judge whether there is a risk by comparing the monitoring critical indicators

2. Judge the impact risk

according to the amount of pulverized coal discharged and its change law, compare it with the amount of drilling cuttings at the boundary of the work face. If the measured index is less than the critical amount of drilling cuttings, it indicates that there is no impact tendency in the construction area. At this time, the work face can be produced normally

if the measured index is equal to or greater than the critical amount of drilling cuttings, or there are dynamic phenomena in the hole, such as suction, sticking, impact in the hole, sound, large particle size of pulverized coal, abnormality, etc. It indicates that there is a risk of impact in the construction section. At this time, the person in charge of the district team on site shall withdraw according to the measures, and report to the mine dispatching room at the same time. The chief engineer shall organize relevant personnel from the impact prevention department, production department, safety department and so on to conduct a joint review and formulate hazard relief measures

3. Implement risk relief measures

the coal seam pressure relief drilling is adopted at the heading face to relieve the danger. When the expected effect is not achieved through inspection, the coal body pressure relief blasting is adopted until the danger is relieved

4. Verify the effect of hazard relief

after implementing the hazard relief measures, use the drilling cuttings method for verification. If the measured index is less than the critical drilling cuttings, it indicates that the construction area has no impact tendency after hazard relief. After the joint review and agreement of the impact prevention department, production department, safety department and chief engineer, the production in the area can be resumed

if the measured index is equal to or greater than the critical drilling cuttings, it indicates that the hazard relief measures have not achieved the expected effect, so continue to take targeted hazard relief measures, and then verify the drilling cuttings method after the implementation of the measures until the measured index is less than the critical drilling cuttings. The chief engineer shall organize relevant personnel from the anti scour department, production department, safety department and other departments to review and approve on site, and then resume production in this area

IV. safety technical measures

1. Before entering the head-on, the construction personnel shall first check the top, side and bottom plate within 100m behind the head-on. If the following phenomena are found, there may be a risk of pressure: the shallow or deep reading of the stratification separator is greater than 5cm, the relative displacement of the two sides is large, the coal wall has bulge, flaky side and dry crack, and makes a gurgling sound, and sometimes the coal is suddenly extruded or thrown out; The formation noise intensifies, and the anchor bolt nut collapses

2. When there is a danger of impact in a certain area or the anti impact personnel are carrying out the dangerous work, the personnel irrelevant to the anti impact are strictly prohibited from entering the area, the relevant equipment must not be operated, and the personnel of the construction unit must provide convenience for the anti impact work

3. The maintenance and cleaning of the roadway in the anti scour area must be strengthened, and the support quality and roadway section of the roadway must meet the design and safety requirements

4. The excavation roadway must be washed regularly to prevent dust. The 50m heading roadway must be washed once every small shift, and the rear roadway must be washed once every two days. Ensure that there is no dust and dryness in the roadway. The distance from the installation site of the explosion-proof water tank to the head is m, and the water volume is more than 200 m3 (roadway section). The installation quality and other requirements must comply with the relevant provisions of the regulations, and a large number of factories will close down and add water to it regularly

5. The air flow purification water curtain must be installed in the roadway. The installation length, the number of nozzles, the direction of spray, and the position of the water curtain valve must meet the requirements

6. The anti scour personnel of the danger relief operation and the personnel working in the area with impact danger should always pay attention to the changes in the surrounding environment, and immediately withdraw in case of abnormalities. In case of sudden and frequent plate gunfire, continuous sound on the coal wall, sudden bulging of the coal wall, large coal outburst, obvious intensification of surrounding rock activities, etc., they should withdraw from the area as soon as possible, set up a warning, and stop the power of the working face and return air flow, At the same time, report the situation to the mine control room in detail

7. If any working face in the dangerous area is shut down for more than three days, the coal powder quantity must be tested by the erosion prevention department one day before resuming the construction. The construction can be resumed only after confirming that there is no danger

8. It is judged that there is rock burst when there are the following phenomena: ① dynamic phenomena in the hole, such as drill suction, drill sticking, impact in the hole, sound, large particle size of pulverized coal, abnormality, etc. ② The drilling powder rate index exceeds the critical index. (see the index table of pulverized coal rate)

9. When the drilling personnel find the above phenomena, it is determined that there is a risk of rockburst. All personnel on site should immediately stop working, withdraw to a safe place in the fresh air flow of -785 crosscut, and report to the mine dispatcher for instructions. The construction can be resumed only after it is determined that the rockburst is relieved, and the excavation is carried out while exploring

v. drilling quality assurance measures:

1. During the drilling construction, the on-site team leader will supervise and accept the drilling. The depth, diameter, angle and number of accepted drilling holes must be reflected in the statement. In addition, the team leader of the middle and night shift will also supervise and accept the pressure relief holes of the morning shift and report them to the statement

after adopting the exchange hydraulic technology

2. Strictly assess the non-standard and unqualified construction pressure relief holes, and strictly assess the lax acceptance of the shift leader

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