Outburst prevention design and safety technical me

The outburst prevention design and safety technical measures of the heading face

1. The project location, quantities and surrounding mining conditions

xx heading face is located in the east wing of the first division of XX coal mine, east of the fifth exploration line, opened at XXX, heading along the 7 # layer roof, with an orientation of 4154 ′ 20 ", and the design length of the roadway is 681m

to the west of the roadway is XX track roadway, and to the south is 110710 working face, which is not mined; In the upper xx# coal seam, XX, 110208 West working faces have been mined; XX working face in the lower xx# coal seam has also been mined

2. Corresponding surface conditions

xx there are no important buildings on the corresponding surface, which is a gentle slope barren mountain terrain

3. Coal seam condition and characteristics of roof and floor 11 # coal seam is black block, mainly bright coal, strip structure is

xx, tunneling along the roof of 7 # coal seam, 7 # coal seam is black, mainly powdery, rare block, semi dark briquette, and the gangue is carbonaceous mudstone, with a coal thickness of 0.8~1.75m. The main roof is gray mudstone, argillaceous silt and gray white siltstone, the direct roof is gray fine sandstone, medium thick layered with horizontal bedding, and the pseudo roof is gray silty mudstone and mudstone, containing plant leaf fossils and siderite nodules; The pseudo bottom is gray mudstone and argillaceous siltstone, and the direct bottom is gray medium thick layered fine sandstone, with horizontal bedding, containing massive siderite nodules and plant fossils

4. Geological structure

xx 230m before tunneling, a fault with a drop of 6m was encountered

5. Hydrogeology

the hydrogeological conditions of this roadway are simple, and it is expected that there will be no impact of water damage, and there is dripping water on local roof

6. Gas geology

in July 2008, Chongqing Branch of the General Academy of Coal Sciences measured the basic parameters of gas in the 4 # and 7 # coal seams in the first division of XX coal mine and concluded that: the 4 # and 7 # coal seams in the first division of XX coal mine have outburst risk, the original gas pressure of the 7 # coal seam is 2.13mpa, and the gas content is 10.8387m3/t

this design is prepared in order to do a good job in the outburst prevention management in the excavation process of XX heading face

II. Outburst prevention design and safety technical measures

according to the instructions of the group company: advance geophysical exploration measures must be strictly implemented for tunneling within the effective protection range, and "four in one" regional comprehensive outburst prevention measures must be strictly implemented in geological structure areas in accordance with the requirements of the provisions on the prevention and control of coal and gas outburst; If the outburst prevention index in the area of effective protection exceeds the standard, the "four in one" local comprehensive outburst prevention measures must be strictly implemented in accordance with the requirements of the provisions on the prevention and control of coal and gas outburst

xx specific protective layer mining conditions and protection effects have been described in the evaluation report on outburst elimination effect of XX working face, and this design will not be repeated

regional verification

refer to articles 57, 74 and 75 of the provisions on the prevention and control of coal and gas outburst. The drilling cuttings index prediction method is used to conduct regional verification twice for XX every 50m. The regional verification design is as follows:

(1) use electric coal drill to drill 3 in the soft stratification at the head of the roadway Ф 42mm drill holes, of which 2 # drill holes are opened in the middle of the working face, parallel to the tunneling direction, with a depth of 8m. 1 # and 3 # drill holes are opened at a position 1.0m away from the two sides of the roadway, and the included angle with the centerline of the roadway is 25?, The hole depth is 10m, which is expected to be controlled to 3.2m outside the roadway contour. The regional verification drilling layout is attached

(2) measure the total amount of drilling cuttings s in the 1m section such as maintenance cost, protection cost, etc. every 1m of drilling, and measure the desorption index K1 value of drilling cuttings every 2m of drilling. If the measured k1max value is less than 0.6ml/g min1/2 and Smax is less than 6kg/m, the inspection area is verified as a non protruding danger area; On the contrary, it is a prominent dangerous area

when the area is verified to be free of protruding dangerous areas, tunneling operation shall be carried out after protective facilities are taken; When the area is verified to highlight the situation of the dangerous area, take "four in one" local comprehensive outburst prevention measures

local comprehensive outburst prevention measures

according to the requirements of Article 58 of the provisions on the prevention and control of coal and gas outburst, if XX an inspection area is verified to be in danger of outburst, the local comprehensive outburst prevention measures must be implemented for future excavation operations in this area

(I) local outburst prevention measures

local outburst prevention measures are shallow hole discharge in advance, that is, 9 head-on construction at the working face Ф The advanced discharge drill hole with a depth of 89mm and a depth of not less than 11m is opened in the middle of the head-on coal body, 1.2m away from the bottom plate, with a spacing of 0.5m. The drill hole is controlled to the range of 11m in front of the roadway and 6.2m outside the roadway contour. The gas and stress in the coal body within the control range are discharged, and the discharge time shall not be less than 8 hours. The drilling layout is attached

(II) effect inspection of local outburst prevention measures and relevant regulations

1. The inspection holes for the effect of local outburst prevention measures are arranged according to the construction parameters of the verification holes in the above areas

2. Measure the total amount of drilling cuttings s in the 1m section every 1m of drilling, and measure the desorption index K1 value of drilling cuttings every 2m of drilling. If the measured k1max value is less than 0.6ml/g min1/2 and Smax is less than 6kg/m, the measures are proved to be effective; On the contrary, the measures are invalid. If the measures are effective, it is allowed to drive forward on the premise of taking safety protection measures. During the driving process, an effect inspection hole lead distance of not less than 2m projection hole depth must be left; When the measures are invalid, the efficiency inspector shall order the excavation to stop, report to the ventilation duty room and the mine dispatching room, and continue to take local outburst prevention measures (extend the discharge time)

(III) safety protection measures

the safety protection measures taken during excavation include the establishment of compressed air self rescue system, carrying self rescuers, and the establishment of forward and reverse anti outburst dampers

1. Establish compressed air self rescue system

the compressed air self rescue system is installed on the compressed air pipeline and installed by the construction unit. The compressed air self rescue system must be intact and easy to use. A group of compressed air self rescue system is installed every 100m from the door of XX to the head of XX. The last group of search engines with a distance of m from the head of XX is to process and protect a batch of pre collected pages. Each group of compressed air self rescue system can be used by at least 5 ~ 8 people, and the compressed air supply shall not be less than 0.1m3/min for each person who reduces the pressure of energy resource shortage

2. Carry self rescuers

all personnel entering the well must wear isolated self rescuers and be familiar with the use of isolated self rescuers

3. Establish anti outburst forward and reverse dampers

build a group of two forward and reverse anti outburst dampers in the 11e7 # layer centralized transportation roadway. The distance between dampers is not less than 4m, the thickness of damper wall stack is not less than 800mm, and the depth of embedded solid coal around the roadway is not less than 0.5m, and the thickness of damper plate is not less than 50mm. The gutter and chute hole passing through the damper must be equipped with anti countercurrent isolation device, and the baffle of the anti countercurrent isolation device is processed with wood plate with a thickness of not less than 50mm. The iron air duct on the anti outburst damper wall must adopt the anti countercurrent iron air duct

IV). Other safety technical measures

1. Local ventilation and gas management

(1) the local ventilator adopts double fans and double power supplies, and is installed in the full negative pressure air flow of XX. It is strictly prohibited to stop at will to ensure the stability and reliability of the air flow and ventilation system. The soft air duct with a diameter of 800mm shall be used, and the distance between the air duct and the cable hanging shall not be less than 300mm. The fan position must be hung with a management board, which requires complete contents, accurate data and neat hanging

(2) the local fan must realize "three special and two locking", and the air duct must be hung straight without breach and air leakage; Local ventilators must be managed by specially assigned personnel, and unplanned air shutdown is not allowed. There must be special ventilation safety measures for planned air shutdown

(3) the working face must be equipped with full-time gas inspectors with valid certificates, and it is strictly prohibited to work without certificates; The gas inspection shall be free of empty, leakage and false inspection; Do not take off. 4. The fixture equipped with the zigzag testing machine should be coated with anti rust oil for storage; Sleep on the post

(4) when the gas concentration in the air flow of the working face reaches 0.8%, the operation must be stopped, the power supply must be cut off, and the personnel must be evacuated for treatment

(5) when the gas concentration in the return air flow of the working face exceeds 0.8%, the work must be stopped, the personnel must be evacuated, and measures must be taken to deal with it

(6) when the gas concentration accumulated in the space with a volume greater than 0.5m3 in the roadway reaches 1.5%, the work must be stopped within 20m nearby, the personnel must be evacuated, and the power supply must be cut off for treatment

(7) for electrical equipment whose power supply is cut off because the gas concentration exceeds the regulations, power transmission can be resumed only when the gas concentration drops below 0.8%

(8) after the local ventilator stops running for some reason, it must stop working immediately, withdraw all personnel to the ground, cut off the power supply, and the gas inspector should set up a fence at the air inlet side of XX damper, hang warning signs, prohibit personnel from entering, report to the mine control room and ventilation shift room, and assign special personnel to stand guard

(9) when the gas concentration in the air stop area exceeds 0.8% and does not exceed 3%, the gas inspector shall take safety measures to control the air flow for discharge according to the arrangement of the leader on duty in the ventilation work area; When the gas concentration in the ventilation area exceeds 3%, the ventilation work area shall prepare gas drainage measures, which shall be reported to the chief engineer of the mine for approval, and the rescue team shall discharge gas in strict accordance with the measures. When the gas concentration in the air stop area reaches or exceeds 3% and cannot be handled immediately, the air stop place must be closed within 24 hours

(10) it is strictly prohibited to operate without wind, breeze and gas

2. Electromechanical equipment management measures

(1) electrical equipment must have a factory certificate, and after the inspection of full-time explosion-proof personnel, it is strictly prohibited to use explosion-proof appliances, and experiments must be carried out before using wind power locking devices