Outburst prevention measures for excavation of the

Outburst prevention measures for air return roadway excavation

(I) process flow

in the excavation process, we must strictly adhere to the criteria of regional outburst prevention methods first and partial outburst prevention methods. See Figure 1 for the outburst prevention process flow

(II) the working face of 11031 return air roadway is subject to the mining shelter environment

1. The relationship between 11031 return air roadway and the shelter layer is shown in the attached figure/2

2. According to the underground actual and mining relationship diagram, the 270 meter excavation of 11031 return air roadway is sheltered by the mining of 1 # layer (the interval between 1 # layer and 3 # layer is 11.5 meters), and its mining has sheltered outside the contour line of 11031 return air roadway, with the upper side greater than 20 meters and the lower side greater than 10 meters

3. During the excavation of 11031 return air roadway, the regional result inspection and regional verification must be stopped (the style of regional result inspection and regional verification has been stopped in detail in the regional comprehensive outburst prevention method). When any of these inspection results is a convex risk area, if it is declared that the asylum result is valid, it must be stopped according to the convex coal seam and the regional outburst prevention method must be adopted again

(III) regional comprehensive outburst prevention method

1. Regional outburst prevention method

① the 11031 return air roadway adopts the regional outburst prevention method for mining the refuge layer. The mining environment of the refuge layer: the 270 meter excavation of the 11031 return air roadway is sheltered by the mining of the 1 # layer, that is, the mining of the 1 # layer has been sheltered outside the contour line of the 11031 return air roadway, the upper side is greater than 20 meters, and the lower side is greater than 10 meters

② when the 11031 return air roadway is verified as a raised risk area by the results of the stop area, and it is declared that the mining of the refuge layer is effective, the regional outburst prevention method of pre pumping coal and gas through the layer drilling hole for the construction of the top (bottom) banvas roadway must be designed, and the method of connecting the long interval (greater than 60 meters) pre pumping drilling holes in the task face must be installed to stop the outburst

2. Result inspection of regional outburst prevention method

① contact the actual environment of our mine, and stop the result inspection of regional method by directly measuring the residual gas content and residual gas pressure of the coal body, that is, push the target along the task surface, install 1 group of inspection and test holes every 40m, and install 3 inspection and test holes every time

② the inspection and test holes must be inserted in the coal seam and kept at equal intervals with the surrounding pre pumping holes as far as possible. See Figure 3 for the design of inspection and test holes

③ the residual gas content and pressure of the coal measured by the inspection and test hole are the maximum values. When the gas content of one of the inspection and test holes is ≥ 8m3/t or the gas pressure is ≥ 0.74mpa, it is stated that the regional outburst prevention method is effective, which is a bulge risk area, and the regional outburst prevention method must be re adopted to stop outburst elimination. Until the regional result inspection is effective, it can be stopped as a non bulge risk area

3. Regional verification

when the regional results are verified as no bulge risk area, the regional verification shall be stopped by measuring the K1 value of drilling cuttings gas desorption index, the amount of drilling cuttings and the construction advance drilling (verification hole)

(1) drilling cuttings gas desorption target method

① drilling cuttings gas desorption target method refers to the construction of three drill holes with a diameter of 42mm and a hole depth of M (see attached figure 4 for the design of the prospective drill holes) facing the coal body in front of the task. All major automakers are introducing innovative cargo space to measure the drilling cuttings gas desorption target and the amount of drilling cuttings

② the observation boreholes should be inserted into the soft layer of the coal seam as far as possible. One borehole is located in the middle of the tunneling roadway section and parallel to the tunneling target, and the final hole point of other boreholes should be located m outside the contour lines on both sides of the roadway section

③ measure the total amount of drilling cuttings s in the 1m section every 1m of drilling, and measure the target K1 value of drilling cuttings gas desorption every 2m of drilling

④ when the measured K1 value of gas desorption target of drilling cuttings is less than 0.4ml/(n1/2) and the Smax value of drilling cuttings is less than 6.0k g/m, and there is no bulge risk in the environment of gas anomaly, drilling spray, coal cannon on the task surface and other bulge precursors in the drilling process of construction observation, otherwise it is regarded as bulge risk

(2) the regional verification must be performed according to the following requirements:

① first, construct three advance boreholes in the front of the task face, that is, the verification holes (which are used as the regional result inspection holes at the same time). The verification holes are designed to be 65 meters, and the final hole points of the boreholes are at least 20m away from the upper contour line of the control roadway, and the lower contour line is 10m (see Figure 3 for the design of the verification holes), so as to further detect the geological organs in front of the task face and observe whether there are spray holes Bulge precursors such as sticking and jacking

② after the advance drilling construction is completed and there are no obvious bulge precursors such as shotcreting, jacking, and sticking, the area verification will be stopped again by adopting the drilling cuttings gas desorption target method. After the experience shows that there is no bulge risk, the excavation work still needs to save a 20m advance interval and a 2m bulge look ahead interval

③ during the excavation of 11031 return air roadway, its excavation work saved a lot of verification holes with a super front interval of 20m and a convex look ahead interval of 2m

5. When the area is verified to be free of bulge risk, the outburst elimination evaluation shall be stopped, and the tunneling work shall be stopped after the Enron protection method is adopted within the allowable footage with the approval of the company

6. In the process of regional verification, if the construction verification hole has a bulge precursor or there is a grade when stopping looking at the warning, then some comprehensive outburst prevention methods must be performed for the future excavation work in the area

(IV) part of the comprehensive outburst prevention methods

1. The risk outlook of the bulge of the task face

(1) after the verification of the area, if there is a bulge risk or the tunneling task face presents one of the following environments, it is identified as the bulge risk task face:

① in case of the crushing zone of the geological mechanism, including faults, vicious folds, igneous rock intrusion, etc

② the premise of coal seam occurrence has changed sharply

③ mining stress superposition

④ drilling has dynamic scenes such as spray hole, top drill, pinch drill, etc

⑤ the task surface presents a relatively prominent precursor

(2) the dangerous look at the bulge of the task surface is stopped by the target method of drilling cuttings gas desorption. The look style and drilling placement are as described above, but a 2m look hole lead distance must be saved for each look (see attached figure 4 for the look hole design)

2. Outburst prevention method of the task face

(1) when there is a risk of bulge in the view of the task face, the outburst prevention method of stopping the drainage of coal gas by the construction drainage borehole (see attached figure 5 for the design of drainage borehole) must be adopted. Its aperture is not less than 75mm, the spacing in front of the hole depth control task is 60m, the upper side of the drilling control roadway is at least 20m outside the contour line, and the lower side is at least 10m; Two rows and nine in each row shall be installed evenly each time, and the lead distance of at least 20 meters shall be kept in each cycle of the drainage hole. When the concentration of gas drainage in a single hole is less than 10%, the result inspection of the outburst prevention method of the task surface can be stopped

3. Task face method result inspection

(1) adopt the drilling cuttings gas desorption target method to stop the result inspection of the prevention and control of bulge. The inspection hole is inserted between the method holes, and the hole depth, hole diameter and hole layout style. Manager Cao and the customer talked very harmoniously and looked at the hole (see Figure 4 for details). When the results of the method of prevention and control of bulge are verified to be effective, the allowable footage must also ensure that there are many method hole lead distances of more than 20 meters and many inspection hole lead distances of more than 2 meters in the target of the axis line of the roadway. When the outburst prevention method is effective, no matter how much lead distance is left in the method hole, the bulge prevention method must be adopted again (according to the actual environment of the site, confirmed by the chief engineer: continuous pumping or additional pumping hole pumping and other methods shall be adopted) until the results are verified to be effective

when the observation or result inspection is effective, the outburst elimination evaluation shall be stopped, and the mining operation can be stopped only after the Enron protection measures are adopted within the allowable footage approved by the company

(IV) safe technical methods for drilling, hole sealing and pressure measurement

1. Safe methods for escorting the drilling rig and its setting:

(1) the drilling rig and its setting escorting line: air warehouse → main inclined shaft in mining area 1 → 11 track crosscut dump → 11031 return air lane → task face

the receiving and receiving line goes according to the original line

(2) all staff involved in escorting must obey the instructions and placement of the on-site Enron person in charge (drilling team leader)

(3) when loading, unloading and handling in the air, the instructions of the person in charge of Enron on site shall be obeyed. Employees are strictly prohibited from standing under the crane boom

(4) the drilling rig must be bound firmly after unloading, and the sliding surface and staggering surface shall be padded with wooden wedges to prevent the center of gravity deviation caused by staggering on the way, which will cause a falling track or an unexpected environment

(5) the equipment data room should be protected with flexible materials to prevent damage on the way

(6) when manually pushing the cart, it must strictly comply with the provisions of the coal mine safety regulations. When parking, the wheel shaft of the mine car must be free to fall back and securely tied to the track with a steel wire buckle, and the person in charge on site must ensure that there is no potential safety hazard

(7) the following regulations must be followed when manually pushing the cart:

① only one cart is allowed to be pushed at a time, and it is strictly prohibited to push the cart on both sides of the tramcar

② pay attention to the front when pushing

③ it is strictly forbidden to put a speeding car

④ the distance between trolleys in the same direction shall not be less than 10 meters when the track slope is less than or equal to five thousandths, and shall not be less than 30 meters when the slope is greater than five thousandths

⑤ when the roadway slope is greater than seven thousandths, it is strictly prohibited to push manually

⑥ start carting and parking. When carting through turnouts and curves, you should walk slowly, and always look at the environment ahead and withdraw the alarm signal

(8) during transportation, all underground measures and equipment must be protected

(9) when carting through turnouts and curves, you should walk slowly and look at the environment ahead at any time

(from this, the tensile strength of the material can be obtained 10) when pushing the cart, a specially assigned person should be responsible for the safe task, and pay attention to the safe condition of the front and rear of the cart. Staff must work together

(11) when passing through the damper, you must open one after the other. It is strictly forbidden to open two dampers at the same time, and it is strictly forbidden to crash the ventilation measures

(12) during the human escort process, it must be tied with a big rope and placed firmly by the staff to prevent the rig from sliding down and injuring people

(13) when the escort equipment passes through the chute or belt, it must contact the driver. When passing through, the chute or belt must stop running

(14) it is strictly forbidden to use belts and chutes to escort drilling rigs and other materials

(15) during the escort process, all staff must do a good job in self-supporting security tasks

(16) the escorting, receiving and receiving of the drilling rig shall be carried out according to the material transportation line of "11031 air return roadway excavation procedure"

2. Safe methods of putting on airs

(1) public supports should be used as much as possible in the erection of shelves

(2) in the place 5 meters away from the task surface, and ensure that the escape route is smooth, then you can put on airs

(3) the support within 20 meters of the drilling address must be intact

(4) the 11# I-steel on both sides of the roadway is connected with the anchor bolt by steel wire rope

(5) wood wedge or brake rod must be added at the lap joint of 11 i-steel, and the joint must be guaranteed on the same plane to prevent sparks from sliding

(6) both sides of the rear end of the flat plate of the drill are hung on the anchor rod with steel wire rope

(7) the anchor rod for hanging the shelf must be hard, and at the same time, the erected shelf must be stable and reliable

(8) see attached Fig. 6 for the installation of drilling rig frame

3. Check the drilling rig

(1) whether the oil quantity is enough (subject to the oil standard), whether the oil quality is qualified, and whether there is precipitation

(2) whether the oil circuit is qualified

(3) check whether the cold water is enough

(4) whether the gripper is flexible and easy to use

(5) identify whether there is water leakage or air leakage

(6) whether the oil circuit leaks oil

(7) inching