Safety technical measures for gas drainage hole sealing construction

In order to ensure the hole sealing effect of drilling construction in our mine and standardize the manual hole sealing process, this construction safety technical measures are specially formulated:

1. In order to ensure the quality of drilling and hole sealing, the construction team must notify the production department of the drilled holes after the on-duty construction, and the buried pipes can be sealed only after the acceptance of the hole inspector of the production department.

2. Before sealing the hole, the coal and rock powder in the borehole must be removed, and the hole should be sealed by grouting with polyurethane mortar pump.

3. Sealing materials: polyurethane, cement, sand and towels.

4. When sealing the hole, use a 2-inch hose with a length of 12m. It is forbidden to block the hole at the innermost 2m(4 cm hole) of the hole. Block the nozzle with a wooden cone at the outer mouth of the hose to prevent coal dust from entering the tube; At a distance of 2m from the inner hose, seal the hole with a towel and polyurethane (2m in length).

5, hole sealing method:

A: First, tie the 2m front end of the drain pipe with towel and iron wire. B, liquid medicine preparation and hole sealing: take two kinds of liquid medicine A and B, pour them into a container according to a certain proportion, prepare the liquid medicine to the inlet of the hole sealing tube, mix and stir until it is milky white, then pour it on the tied towel, quickly wrap the hole sealing tube tightly and send it into the hole. It must be finished in two minutes. Otherwise, the polyurethane begins to expand, and the hole sealing pipe cannot be sent into the hole.

6, hole sealing to ensure that the hole is not leaking, hole sealing pipe is not loose, and the gas path in the hole is smooth. The orifice shall be sealed with cement by special personnel, the length of the sealing section must be greater than 0.5m, and the cement at the orifice must be smooth.

7, mortar hole sealing should be paid attention to:

(1), mortar hole sealing requires casing, and the outer end of casing can be made of steel pipe or plastic pipe.

(2) The hole sealing part needs reaming, and the aperture is generally not less than100 mm..

(3) When sealing the hole, firmly fix the casing in the drilling hole, and the fixing method can adopt the method of wrapping woven bags around the casing. Generally, the casing should be exposed from the orifice 10 ~ 15cm;

(4) After running casing, use grouting pump to send the prepared cement mortar into the borehole outside the casing wall (the ratio of cement, expansion agent and water is 10: 1: 6).

(5), artificial send mortar hole sealing, to send mortar and tamping; When sealing the hole with pumping mortar, the grouting pipe should be fixed in the borehole and the orifice should be closed. At the end of the work, the mortar in the pump should be cleaned with water.

8, drilling hole sealing, must be timely union drainage, union drainage pipe must be retained before drilling, union pipe joint must be connected with special glue. To ensure that the pipeline does not leak and the pipeline drains smoothly.

20 1 1 February 15

Wangjiazhai Coal Mine in Xingren County

Safety technical measures for gas drainage hole sealing construction

20 12 February 15

See you at the meeting

Security part:

Dispatching room:

Production department:

Electromechanical mine manager:

Safety mine manager:

Production manager:

Chief Engineer:

Sealing technology, sealing material and sealing equipment of gas drainage drilling hole

1 overview

At present, the commonly used hole sealing methods for gas drainage drilling are polyurethane hole sealing and cement hole sealing. Commonly used cement sealing methods include manual cement delivery, compressed air cement delivery and grouting cement delivery.

The sealing depth of polyurethane sealing hole, artificial cement sealing hole and compressed air cement sealing hole is generally less than 5m, which is suitable for short-time gas drainage drilling hole sealing and short broken coal wall gas drainage drilling hole sealing in roadway; The hole sealing depth of grouting hole sealing pump can reach more than 20m, and the water cement ratio of cement slurry used for hole sealing can reach 0.4: 1 (water: cement). This kind of high consistency cement slurry does not shrink basically in the borehole, and is suitable for plugging various gas extraction boreholes. This is a common hole sealing method for gas drainage drilling at present.

Therefore, this paper mainly introduces BFZ- 10/ 1.2(2.4) mine grouting hole sealing pump and its hole sealing technology.

2 grouting hole sealing pump and its hole sealing characteristics

2. 1 has the characteristics of stirring and conveying high-consistency cement slurry at the same time, and the mass ratio of water to ash reaches 0.4: 1 (water: cement).

2.2 It is not necessary to ream the hole sealing section, nor to send the grouting pipe to the bottom of the hole to be sealed, just fix and plug the grouting pipe at the hole to be sealed.

2.3 Due to the above characteristics of 1 and 2, the hole sealing process is greatly simplified and the labor intensity of hole sealing operation is reduced.

2.4 The high-concentration cement slurry basically does not shrink, which ensures the tightness of hole sealing of any drilling hole and improves the hole sealing quality of drilling holes.

3 main structure and working principle of grouting hole sealing pump

BFZ- 10/ 1.2 (2.4) Mine grouting hole sealing pump mainly includes mine flameproof electromagnetic starter (1), explosion-proof motor (2), coupling (3), speed change system (4), agitator (5) and operating clutch (6).

3.2 BFZ-10/1.2 (2.4) Photo of grouting hole sealing pump

3.3 working principle

3.3. 1 cement slurry mixing

The motor is connected with the variable speed transmission system through the coupling, and the start and stop of the motor are controlled by the mine flameproof electromagnetic starter. When the explosion-proof motor is running, the variable-speed transmission system drives the moving blades of the mixer to rotate, so that the cement and water added into the mixer according to the water-cement ratio are continuously mixed until the mixture is uniform and the cement slurry is stirred. In the process of mixing cement slurry, the clutch is in a disengaged state under the action of the operating handle, and the mud pump does not work.

Transportation of cement slurry

After the cement slurry is stirred evenly, pull up the clutch handle to make the clutch in the engaged state. At this time, the transmission system drives the slurry pump to rotate under the action of the clutch. The suction negative pressure of the slurry conveying pump in the rotating process sucks the cement slurry evenly stirred in the mixer into the pump body through the connecting pipe, and outputs it from the pump outlet after being pressurized, thus completing the conveying of the cement slurry. During the operation of the slurry pump, the mixer is always in a stirring state.

overpower protection

In the process of mixing and conveying cement slurry, when the cement slurry is too thick and the load torque is greater than the actual output torque of the motor, the motor stalls and the working current of the motor rises rapidly. When the actual current reaches the cut-off current set by the mine flameproof electromagnetic starter, the mine flameproof electromagnetic starter acts to automatically cut off the power supply, thus achieving the purpose of protecting the motor.

4 Main technical parameters of grouting hole sealing pump

serial number

name

parameter value

1.2

2.4

1

working pressure range

0MPa~ 1.2MPa

0 MPa ~ 2.4 MPa

2

Output flow

8 l/min ~ 10 l/min

three

Working voltage of motor

380 volts or 660 volts

four

power of motor

2.2 kw

five

Agitator volume

40 liters

six

outline dimension

1820×426×878mm3

2 120×426×878mm3

seven

quality

255㎏

275㎏

eight

Working voltage of mine flameproof electromagnetic starter

380 volts or 660 volts

5 Installation and debugging of grouting hole sealing pump

Place the hole sealing pump on the ground or flat car and fix it so that it cannot shake at will during operation.

5.2 debugging

5.2. 1 Debris removal

Before starting the machine, remove the impurities that may exist in the mixer, remove the cleaning plug on the pulp feed pump and clean the mixer with clean water. After cleaning, clean the screw plug again and inject an appropriate amount of water into the mixer.

5.2.2 Determination of running direction of slurry pump

After connecting the power supply, test with clean water. After turning on the motor, pull up the clutch operating handle, so that the clutch is in the engaged state, and the pulp feed pump starts to rotate, and the outlet of the pulp feed pump can pump clean water, so that the rotation direction of the motor meets the working requirements of the pulp feed pump. If there is no clear water at the outlet of the pulp pump, the following situations may occur:

① The rotation direction of the motor is inconsistent with that required by the slurry pump, and the power supply of the mine flameproof electromagnetic starter should be reversed;

② The slurry supply pump was not cleaned after the last work, and the inlet or outlet of the slurry supply pump was blocked due to the solidification of cement slurry, so the slurry supply pump should be cleaned or repaired.

③ The whole machine can be used when there are no abnormal sounds such as jamming and resistance during the test.

6 Operation of grouting hole sealing pump

For non-coal seam gas drainage; The gas drainage pipe can be a steel pipe with an outer diameter of 40mm, an antistatic plastic pipe or a cloth hose.

The gas drainage in this coal seam is carried out in the mechanical mining face: considering the coal cutting operation of the shearer, the gas drainage pipe should adopt plastic pipe or cloth hose with antistatic effect.

6.2 Pretreatment of Gas Discharge Pipe

The ultimate purpose of hole sealing is to form a cement slurry curing section with tight sealing performance when the cement slurry wraps the gas drainage pipe. In order to ensure that the slurry can effectively fill the hole to be sealed in the grouting hole sealing stage, and ensure that the slurry wraps and fills the gas drainage pipe, the gas drainage pipe must be pretreated, and the treatment methods are as follows:

1) The front end of the gas drainage pipe should be tied with cotton yarn, and the tied cotton yarn should be tied into a ponytail, so as not to tie the cotton yarn into a ball and make it difficult to send the pipe.

2) The distance between the bundled cotton yarn and the end of the gas drainage pipe should be greater than 0.5m, so as to prevent the gas drainage pipe from being blocked due to the leakage of cement lottery in the process of grouting hole sealing.

Pretreatment of gas drainage pipe is shown in Figure 6.3 Burying of gas drainage pipe.

Send the pretreated gas drainage pipe into the borehole, and avoid pulling the gas drainage pipe outward during the pipe feeding process. After the gas drainage pipe is sent to the predetermined position in the borehole, it should be pulled out slightly to make the cotton yarn ball, and the end of the gas drainage pipe should be closed to prevent the cement slurry injected into the borehole from flowing into the unclosed hole section of the borehole, as shown in the figure.

Schematic diagram of gas drainage pipeline embedding

6.4 Embedding of Grouting Pipe

After the gas drainage pipe is buried, the grouting pipe (one end of which is connected with the outlet of the hole sealing pump) is sent to the borehole, and the length of the grouting pipe sent to the borehole should be not less than 500mm. After grouting pipe is sent into the borehole, the drain pipe and the orifice section of grouting pipe are blocked with cotton yarn balls, and the length is not less than 200mm, so as to prevent grouting pipe from exiting outward during the process of injecting cement slurry; For the borehole with large elevation angle, the gas drainage pipe should be wedged with a wooden wedge wrapped with cotton yarn at the borehole mouth to ensure that the cement slurry is pressed into the deep part of the borehole, as shown in the figure.

Schematic diagram of grouting pipe embedding.

6.5 Preparation of Cement and Clear Water

6.5. 1 Determination of dosage of mixed cement slurry:

The amount of mixed cement slurry is calculated according to the following formula:

G=(V 1-V2)×K×γ

Where: g is the mass of the required mixed cement slurry;

V1-drilling volume within the range of hole sealing length;

V2 —— the volume of gas drainage pipe or water injection pipe within the range of hole sealing length;

K coefficient, k =1.2;

γ-density of cement slurry after mixing. The density of cement slurry with water cement ratio of 1: 0.4 (cement: water) is about 2t/m3.

6.5.2 Determination of dosage of cement and clear water

According to the actual use and laboratory test results, the mass ratio of cement slurry with good hole sealing effect is 1: 0.4 (cement: water).

The dosage of cement and clean water required to prepare the cement slurry with the mass of g is as follows:

Cement dosage g ash =G/ 1.4

Water consumption g water = G- G ash

6.6 Preparation before startup

Before starting the machine, remove the impurities that may exist in the mixer, remove the cleaning plug on the pulp feed pump and clean the mixer with clean water. After cleaning, clean the screw plug again and inject an appropriate amount of water into the mixer.

6.7 Mixing of Cement Slurry

Pour the clean water prepared according to the water cement ratio into the mixer, operate the button of the mine flameproof electromagnetic starter, turn on the explosion-proof motor, gradually add cement when the mixer is in normal operation, and continue to add cement after the cement added to the mixer last time is dispersed; When adding cement, it is necessary to avoid mixing paper and other impurities into the mixer, and the mixing time of cement slurry should be no less than 10min.

6.8 hole sealing operation method

6.8. 1 hole sealing system

The hole sealing system prepared according to the above steps consists of BFZ- 10/ 1.2(2.4) mine grouting hole sealing pump (1), drilling hole (2) and grouting pipe (3), as shown in the figure.

6.8.2 Hole sealing operation

Pull up the clutch operating handle to make the clutch engaged. At this point, the slurry pump starts to work, and the slurry in the mixer is sucked into the slurry pump, pressurized and injected into the hole sealing section of the drilling hole to be sealed by grouting pipe.

① The engagement and disengagement of the working clutch do not need to stop;

(2) In the process of operating the clutch through the handle, it is required to pull up or push down the handle forcibly and quickly, so that the clutch can be fully engaged or disengaged at one time, so as to prevent the clutch meshing teeth from being damaged due to mutual wear in a short time when the clutch works in an incomplete engagement or disengagement state;

(3) When pulling up the handle to force the clutch to engage, if it fails once, pull it hard again, or quickly press down the handle to operate it again;

④ When the clutch is engaged, the operating handle must be kept in upward tension.

6.8.3 Control of hole sealing length

① For horizontal drilling and inclined drilling, when the pressure of cement slurry in the hole to be sealed rises, the cement slurry overflows from the hole to be sealed or the cotton yarn blocked is pushed out of the hole, the hole sealing length reaches the designed hole sealing length. At this time, the grouting pipe should be slowly pulled out of the hole, and the clutch operating handle should be pressed to make it in the disengaged state.

(2) For the upward hole, the amount of cement slurry injected into the hole to be sealed should be strictly controlled to ensure the hole sealing length, so as to avoid the failure analysis and troubleshooting of the grouting hole sealing pump for the seventh hole to be sealed.

The pressure in the hole increased greatly, which led to the failure of orifice plugging.

Fault phenomenon

cause analysis

exclusive method

comment

No pulp

Motor reverse direction

Reverse connection power supply of mine flameproof electromagnetic starter

Small flow

Pump body blockage

Clean up the large sundries at the pulp inlet and outlet; If the mud is not discharged or the flow rate is low, the pump body should be disassembled and cleaned.

Pressure small

The gap between stator and rotor is too large.

Replace the pump body

Pump body is unqualified

The flameproof electromagnetic starter for mine is powered off during mixing and conveying.

The consistency of cement slurry is too strong.

Add a proper amount of clean water to the agitator, and clean up the thick cement slurry in the grouting pipeline at the same time, and then start the button of the mine flameproof electromagnetic starter.

8 Maintenance and maintenance of grouting hole sealing pump

1. Strictly prevent sundries from entering the slurry pump through the mixer, causing damage to the pump body of the slurry pump;

2. Clean the whole machine after each use, so as to prevent the cement slurry from accumulating in the agitator and slurry pump, causing damage to the machine body;

1) Unscrew the screw plug of the pulp feed pump and clean the agitator and connecting pipe with water;

2) Re-tighten the screw plug of the pulp feed pump for cleaning, inject clean water into the mixer, turn on the motor, and pull up the clutch operating handle to make it in meshing state until the outlet water of the pulp feed pump becomes clean;

3. After each use, clean the cement slurry and cement ash on the surface of the hole sealing pump.

9 Safety measures for grouting hole sealing pump

1, it is forbidden to idle the pulp pump.

2. When cleaning, it is forbidden to clean the screw plug of the slurry pump with hard objects to prevent damage to the rubber sealing sleeve.

3. For the hole sealing operation of continuous drilling holes, when the cement slurry is stirred for many times, the dry and thick cement slurry stranded in the pump body and grouting pipe will be discharged to prevent the blockage caused by condensation in a short time. The specific operation is: inject clean water into the mixer to stir, and replace the dry and thick cement slurry in the pump body and grouting pipe with clean water or cement slurry.

4. In the process of grouting and hole sealing, the cleaning plug of the slurry conveying pump should be tightened to prevent the slurry conveying pump from reaching the rated negative pressure due to air leakage, so that the pumping capacity of the slurry conveying pump to the cement slurry in the mixer is reduced or the slurry cannot be sucked.

5. When the temperature drops in winter and the pulp feed pump can't be started, remove the clutch cover, use the four holes on the clutch to forcibly turn the pulp feed pump for several turns, and then start it again.

6. It is forbidden to start the pump without installing the coupling and working clutch cover;

7. It is forbidden to start the pump without checking the leakage.