Comprehensive outburst prevention technical measur

Technical measures for comprehensive outburst prevention of machine roadways

3, Qianyuan coal mine "107 lower 3 machine roadways excavation operation procedures"

4, relevant policies, laws, regulations and gas control norms and standards

II. Overview:

107 the lower 3 machine lane is arranged in the south of the 1140 outer bypass, and the opening elevation is raised by 1.4m at 36m into the 1140 outer bypass opening. The opening elevation is +1144. First, the pseudo slope of 30 degrees is excavated along the coal seam at the orientation of 185 degrees, and then the transportation chute is excavated along the coal seam at the orientation of 174 degrees. The work quantity is 225m. 107 the construction of xia3 machine lane must not only strictly follow the central line given by the production technology department, but also strictly abide by the "four in one" outburst prevention measures and the circular water exploration and drainage system of "when there is excavation, it is necessary to explore first and then excavate", so as to strictly prevent the occurrence of prominent water seepage accidents. 107 lower 3 machine roadway is designed to be 3M wide, 2.3m high and 5.93m2 in area

occurrence characteristics of coal (rock):

1 7 # coal seam is black semi dark to semi bright pulverized coal, with complex structure, coal seam inclination of 41, coal seam occurrence is relatively stable, and its corresponding surface is barren mountains, steep mountains, and no water body

2. Coal seam, roof and floor of coal seam and coal quality

7# coal seam structure: Black semi dark to semi bright pulverized coal, complex structure, coal seam inclination 41, coal seam occurrence is relatively stable, coal seam stability is general, and coal quality is good

the pseudo roof is about 0.1 m thick dark gray mudstone, and above it is about 0.5m thick argillaceous limestone, which is stable in the whole region; The direct top is dark gray argillaceous siltstone (mixed with multiple layers of calcareous fine sand strips); The main roof is gray thick calcareous fine sandstone. The false bottom is about 0.5m thick brown gray mudstone, which is easy to expand in case of water; The old bottom is gray fine sandstone

3. Occurrence characteristics of coal (rock) layer:

7# coal ceramic material bending strength testing machine can carry out static (tensile force, drawing force, contraction, zigzag, shear, etc.) and dynamic tests on standard samples or components under axial loading. It is black semi dark to semi bright pulverized coal, with an average thickness of 2.5m, a hardness coefficient of 0.4, an inclination of about 41, and a coal seam strike of about 174

hydrogeology: the hydrogeology of the mine is of class II and type I, that is, it takes atmospheric precipitation as the supply water source, and the hydrogeological conditions are simple

III. outburst prevention measures:

1 Local comprehensive outburst prevention measures:

(I). Prediction of outburst risk of working face:

1. Prediction method: adopt drilling cuttings index method

2. Use WTC gas predictor to predict. Drill holes with a drill bit with a diameter of 42mm of fried dough twist drill pipe of coal electric drill. Measure the drilling cuttings every 1m and the gas desorption index (K1 value) every 2m. The drilling speed should be controlled at 1m/min

3. Layout of prediction holes: each time, 3 prediction holes are arranged. The position of the final hole of the hole controls 2m outside the contour line of the roadway, which must be 15 ° to the two sides of the roadway 18? The intersection angle of shall be arranged in the soft layer of the same coal seam, and the prediction diagram is attached

4. Selection of critical value: with reference to the provisions on prevention and control of coal and gas outburst, the critical value K1 is 0.5ml/g min1/2, the drilling cuttings s is 6kg/m, and each prediction is 8 ~ 10m. When the prediction value is lower than the critical value, the allowable tunneling distance is determined according to the standard of leaving a sufficient 2m advance projection distance

5. When predicting, the working face has outburst omens such as coal cannon, top drill, spray hole, support pressure, etc. regardless of whether its prediction index value reaches the specified critical value, it is regarded as an outburst dangerous working face, and outburst prevention measures are taken directly

(II) outburst prevention measures:

1. When the prediction index exceeds the critical value, the excavation shall be stopped immediately, and the pre drainage of coal seam gas shall be used as the outburst prevention measures of the working face

2. Control range: the two side holes should form an intersection angle of 75 ~ 78 with the roadway, and the control range of the final hole position of drilling: 7 meters above the upper side and 3 meters below the roadway contour

3. Effective discharge radius: the effective discharge radius of our mine is tentatively 1m

4. Number of drainage boreholes: the coal seam thickness is calculated as 3 meters, and double row boreholes are drilled

number of drainage boreholes: n= ((3+7+2.3) (2 1) + 1) 2, a total of 16

layout of drainage boreholes: see the attached figure

(III) measure effect test:

1. Measure effect test can be carried out only after the hole is drilled as required and one and a half months after pumping

2. Test method of measure effect: the same as the previous prediction method

3. Requirements for measure inspection hole: the depth of inspection hole should be less than or equal to the measure hole, and should be arranged between the two measures, as shown in the following figure

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2

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layout of effect inspection holes

1-measure holes; 2-inspection hole; 3-working face

4. If the measure effect inspection indicators are less than the critical value of the indicators, and no other abnormal conditions are found, the measures are effective; Otherwise, it is judged that the measures are ineffective in fact, and outburst prevention measures should be taken again

5. When the inspection results and measures are effective, if the projection length of the inspection hole and the outburst prevention measure hole to the roadway excavation direction is equal, the excavation can be carried out under the condition that the advance distance of the outburst prevention measures is 5M and safety protection measures are taken; When the projected hole depth of the inspection hole is less than the drilling of the outburst prevention measures, the tunneling operation shall be carried out after taking safety protection measures under the condition that the required advance distance of the outburst prevention measures is reserved and at least 2m advance distance of the projected hole depth of the inspection hole is reserved