Prevention and control of gas by one ventilation and three defenses

1. What is gas? It is a harmful gas dominated by coalbed methane in mines, and sometimes refers to methane (CH4) alone.

2. Nature of gas: gas is colorless, odorless and odorless, with a density of 0.55 relative to air, insoluble in water and nontoxic. When the concentration is high, it will lead to suffocation and death.

3, gas explosion conditions:

(1), gas concentration is between 5% and 65438 06%.

(2) the ignition temperature is 650 ~ 750℃

(3) The oxygen concentration is greater than 65438 02%.

4. Classification of gas grades:

(1) gas mine: relative gas emission ≤ 65438+1100m3/t, absolute gas emission ≤ 40m3/min;

(2) High gas mine: relative gas emission >; 65438+ 100m3/t or absolute emission >: 40m3/min;

(3), coal (rock) and gas (carbon dioxide) outburst mine.

5, the harm of gas explosion:

(1), cause fire, coal dust explosion, burn people, damage the roadway and equipment.

2, produce a lot of toxic and harmful gases.

Gas is the enemy of coal mine safety production, which has caused great losses to coal mines many times. 1990- 1999, 20625 miners were killed in the gas accident alone. We should fully understand the seriousness of gas hazards and always pay attention to preventing gas.

1991April 2 1 day, a gas explosion occurred in the heading face of sanjiaohe coal mine in hongdong county, Shanxi province, and the explosion shock wave raised coal dust again, causing coal dust conduction explosion in the whole mine. All 47 people in the mine/KLOC-0 were killed, and the explosion shock wave also rushed out of the wellhead, causing two serious injuries and four minor injuries on the ground. The total length of underground roadway roof caving is 530m, and the ventilation facilities are completely destroyed.

On September 27th, 2000, a serious gas and coal dust explosion occurred in Muchonggou Coal Mine, Shuicheng County, Guizhou Province, and 162 people were killed, which shocked the whole country. The bloody lesson was extremely sad. Three conditions of gas explosion are indispensable, and the prevention of gas explosion should start with these three conditions.

First, prevent gas accumulation.

(1), locations where gas is easy to accumulate and treatment measures:

(1) Places where gas is easy to accumulate: all places where underground gas emission is large, ventilation is poor or airflow can't reach are easy to accumulate gas, such as the upper corner of the coal mining face, the bottom slot of the working face conveyor, the roof caving space, the vicinity of the roof in the roadway with low wind speed, the blind alley where the wind stops, the coal mining face near the goaf boundary and the vicinity of the shearer.

(2) Treatment measures: change the ventilation mode, hang an air guide curtain or an air bucket, and use high-pressure water or a small local fan to remove the gas in the corner of the return air; Use local fans to remove gas accumulated at local points; Increase the wind speed; Gas drainage should be carried out in blind roadway; The high caving area and wide slope area should be filled with or hung with air guide curtains, and gas inspection should be carried out in each shift.

Second, strengthen gas management and do a good job in the construction of three lines of defense

What are the three lines of defense for gas management? (1) the gas inspector to check the gas, forming the first line of defense. (2) Portable tile detector continuously monitors gas to form the second line of defense. (3) The mine ventilation safety monitoring system continuously monitors the gas to form the third line of defense.

(1), strengthen the gas inspection:

(1), the gas and carbon dioxide in all coal mining faces and retreating faces shall be inspected at least three times per shift, and the heading face with gas emission greater than 1m3/min and the coal mining face with gas and carbon dioxide greater than 3m3/min must be inspected by designated personnel at any time. Check the gas and carbon dioxide in the mining face and the non-production installation face at least twice per shift.

(2), the gas inspector must use optical tile detector to check the gas, and carry not less than 2m hose and inspection stick, and must check whether the instrument is in good condition before entering the well. The gas inspector shifts at the designated place underground, and can check the records; No empty shift missed inspection, no false gas report.

(3) The gas inspector must check the gas according to the inspection route, inspection location, inspection time and inspection times indicated by the tour icon, and report the ventilation scheduling immediately if the gas exceeds the limit.

(4) All gas inspection sites must have gas check card. Fill in the gas check card clearly, completely and accurately. Every time the gas is checked, it must be reported to the ventilation dispatching, and the gas account should be filled in in time after going down the well, so as to achieve the "trinity" of gas record book, gas check card and gas handover report.

⑤ For the blasting site, strictly implement "one shot, three inspections" and "three-person chain treatment". When the gas concentration reaches 65438 0%, it is forbidden to use coal electric drill to drill holes and shoot. And there are measures to prevent the instantaneous gas overrun after shooting.

6, for the mining face, if the gas emission is large or abnormal area, must report to the ventilation department at any time, and according to the instructions of the ventilation department for inspection. Gas engineers should carefully check the high roof, wide slope, high roof caving, cracks and other places where geological structures may exceed the limit at any time.

All landowners, underground welding, gas welding and blowtorch shall not be carried out anywhere. If electric welding and gas welding operations must be carried out underground, safety technical measures must be formulated. The gas concentration in the airflow at the workplace shall not exceed 0.5%.

(2) Some local regulations on gas and carbon dioxide concentration:

(1), mine total return air lane or wing return air lane gas or carbon dioxide concentration exceeds 0.75%, must immediately find out the reason, for processing.

(2) When the gas concentration in the return air lane of mining area and coal mining face exceeds 65,438 0.0% or the carbon dioxide concentration exceeds 65,438 0.5%, it is necessary to stop working, evacuate personnel and take measures to deal with it.

(3) When the gas concentration in the airflow of the mining face and other workplaces reaches 65438 0%, it is necessary to stop drilling holes with electric drills; Blasting is strictly prohibited when the gas concentration in the airflow within 20m near the blasting site reaches 65438 0%.

When the gas concentration in the airflow near the working place such as the mining face reaches 65438 0.5%, the motor or its switch shall be installed within 20m, so it is necessary to stop working, cut off the power supply and evacuate personnel for treatment.

(4) When the concentration of carbon dioxide in the airflow of the mining face reaches 65438 0.5%, it is necessary to stop working, evacuate personnel, find out the reasons, formulate measures and deal with them.

(3) Strengthen the management of portable tile detector:

Mine leaders, electromechanical, ventilation, safety, engineering and other production and business departments above the deputy ministerial level, underground team leaders, supervisors, technicians in charge, team leaders, safety officers, gas workers, mobile electrical assemblers and blasting workers should wear portable tile detectors when they go down the well, and they are not allowed to throw them around, so that the machine can follow people and detect gas at any time.

(4) Strengthen monitoring management:

(1), all mines must be equipped with mine safety monitoring system.

(2), the coal mining face must be set in the working face and its return air gas sensor, gas sensor set in the upper corner of the coal mining face, special tile row lane and tail lane to set up automatic gas monitoring alarm power-off device.

(3), coal winning machine, roadheader must be equipped with airborne gas breaker.

(4) The gas sensor must be set at the return air inlet side of the mechanical and electrical equipment cavern.

(5), the gas sensor should be installed in a good supporting place, the gas sensor should be suspended vertically, not more than 300mm from the roof, not less than 200mm from the roadway help.

6. The gas sensor installed in the mining face shall be maintained by the mining unit and moved according to regulations. When blasting, it should be moved to the safety protection point, and after blasting, it should be moved to the designated position. It is forbidden to stop using the equipment without authorization, and clean it frequently to ensure the normal operation of the equipment. Do not rinse with water.

⑦ The equipment must be debugged, corrected, replaced and maintained regularly in accordance with regulations to ensure the continuous monitoring of gas equipment.

5], noun explanation

(1) Local gas accumulation: refers to the local gas accumulation in the roadway when the volume is above 0.5m3 and the gas concentration reaches 2%.

(2) "Three inspections with one shot" refers to the gas inspection before charging, before blasting and after blasting. 7, control the ignition source:

(1), all downhole personnel are strictly prohibited to carry fireworks and wear chemical fiber clothes.

(2) It is forbidden to use light bulbs, electric furnaces for heating, open flame operation and dismantling miner's lamps underground.

(3) Foam mud and explosion-proof blaster must be used for blasting, and open wire blasting is strictly prohibited.

(4), the team to strengthen the management of mechanical and electrical equipment, put an end to explosion accidents. The belt runs without friction.

5]. It is forbidden for all non-explosion-proof electrical equipment to go down the well, and the underground power supply line should be "three noes" (no chicken feet, sheep tails and exposed joints).

[6], underground tape, cable, pipe, ram, plastic net, etc. Must be flame retardant and antistatic.

Once, in the underground photography, video security measures must be formulated.

8, control the oxygen concentration

(1), underground blind alley should be avoided, when it is unavoidable, it should be closed immediately and listed management should be implemented.

2, after the production face, all equipment must be withdrawn within 45 days, goaf to permanently closed, airtight without air leakage.

9, strengthen the management of roadway through.

(1), before the breakthrough of drivage roadway, before the comprehensive mechanized drivage roadway is 50m apart, and before the other roadways are 20m apart, it is necessary to stop 1 working face and prepare to adjust the ventilation system.

2, well versed in, must be unified command by someone at the scene, stop digging face must maintain normal ventilation, set up fences and warning signs, often check the ram in good condition and the gas concentration in the working face and its return air flow, gas concentration overrun, must be dealt with immediately. Before each shooting in the heading face, there must be a special person to check the gas concentration and return air flow in the heading face with the * * * gas inspector. When the gas concentration exceeds the limit, the operation of the tunneling face must be stopped first, and then the gas treatment should be carried out. Only when the gas concentration in two heading faces and their return air is lower than 65438 0.0% can the heading faces be blasted. Before each blasting, the entrances of two working faces must be guarded by special personnel.

(3), well versed in, must stop all work in the mining area, immediately adjust the ventilation system, after the romantic stability, can return to work.

(4), the distance is less than 20m, parallel roadway connection, must abide by the provisions of the preceding paragraph.