1. 1 Analysis of mine risk area
According to the geological data of the mine and the analysis of the sealing and sealing conditions over the years, it is found that the following locations are prone to accidents.
(1) Near the stop line. Irregular stop-and-go lines are prone to the accumulation of energy, especially when the pressure step is coming from the working surface cycle, and it is easy to cause the large-area roof to hang. Once the coal pillar is unstable and deformed, the roof suddenly falls, which will cause sudden ejection of the old air body, causing an accident.
(2) There are irregular coal pillars. Irregular coal pillars cause accumulation of energy. The shape change of the residual coal column makes the local stress field change and adjust. Once there is a small disturbance in the external source, it will cause the overburden to fall.
(3) Activities with fault participation. During the mining process of the 103 working face, there were more frequent mine earthquakes. According to the seismic phase analysis, the occurrence of the mine shock is not only caused by the falling of the roof, but also shows the fault participation. The results of the later positioning also clearly show that the 103 mineral shock was caused by the activation of the Da Machang fault and the X-F17 and X-F18 faults. Therefore, the activation of the fault is one of the reasons for the roof to fall.
(4) The existence of hard and thick rock layers, once a large area of ​​fracture will provide a power source for the occurrence of mine earthquakes. Based on the above conclusions, carefully conduct the detailed investigation of the sealing within the mine range, and classify them according to the standards of Class I, Class II and Class III. Among them, the level I seal indicates danger; the level II seal indicates that it is dangerous; the level III seal indicates that there is a certain danger. All the sealings are subject to Class A management, and the netting is used for shotcrete reinforcement.
1. 2 Mine shock prevention measures
(1) Strengthen leadership and improve organization. In order to prevent the mine from causing damage during the production process, Baodian Coal Mine established a flood prevention leading group headed by the mine manager. The mine manager is the first responsible person and has an anti-shock office, which is responsible for mine prevention and treatment.
(2) Scientific analysis and technical support. Optimize the design of mining area, analyze and predict the dangerous area, make full use of the existing drill cutting method and roof separation instrument of the mine to monitor, timely grasp the pressure of the roof, and prepare strict protective measures, delineate the dynamic pressure danger zone and reduce the mining footage. Persons who are prohibited from staying in the construction of the restricted area shall take measures to prevent collapse of the anchor tray to ensure the safety of the site.
In order to prevent accidents caused by large-scale mined-out areas and complicated geological conditions, resulting in mine earthquakes and natural fires, Baodian Mine issued the “Notice on Strengthening Permanently Closed Managementâ€, which increased the intensity of closed management and included Procedures, measures and technical specifications.
(3) Strengthen training and improve quality. In order to further absorb the lessons learned from the previous destruction of confined accidents, the use of various forms and forms to increase publicity, such as blackboard newspapers and cultural corridors, has raised the awareness of employees on the dangers of accidents. Through the combination of off-the-job training and amateur training, the staff's theoretical knowledge level, operational skills and emergency response can be continuously improved.
force.
2 Gob area technical management
2. 1 Gas Management
(1) Optimize the ventilation system and adopt equalization measures for the goaf to reduce air leakage in the goaf.
(2) The gas in the goaf is dynamically monitored by setting the beam tube in the high-negative pressure zone and setting the beam tube in the closed wall.
(3) Apply methane and carbon monoxide sensors to the goaf that may be damaged by the mine shock to achieve continuous monitoring.
(4) U-type differential pressure gauge is installed in the goaf of the key points, and the pressure difference between the inside and the outside is measured, and the pressure status of the goaf is grasped at any time.
(5) The key management area is closed, and the gas sampling analysis is performed once a week.
2. 2 Technical measures for permanent closure of goaf
(1) The principle of closure. According to the analysis of the seismic hazard area of ​​Baodian Coal Mine and its impact, combined with the actual situation, the mine danger zone and other key areas are closed according to the following principles: 1 Extend the scope of the enclosed area as much as possible, reduce the unnecessary roadway, reduce the new construction and strengthen the sealing The number of walls; 2 according to the production and connection of mines, new and strengthened closed walls in different time zones and sub-regions; 3 to ensure that the closed wall connected to the goaf of the mine seismic danger zone is strong and does not leak; 4 is convenient for gas in the goaf Observation; 5 to ensure that the ventilation system is reasonable and reliable, easy to ventilate, pedestrians; 6 conducive to the integrity of the subsequent mining system; 7 to ensure the integrity of the grouting, power supply system.
(2) The closed plan of the goaf. In order to prevent the airtight damage caused by the air, the air leakage path is formed, the harmful gas is generated and the natural fire occurs, and the safety protection is taken into consideration, and the actual situation of the newly built or reinforced closed wall site is adopted, and the closed reinforced concrete sealing and flexible protection are used. The method is to fill and seal the new coal material (Rimi II, III), which achieves the purpose of impact resistance, less air leakage and impact resistance. Closed sealing method and requirements: 1 The first construction is high-strength filling and sealing, and the solidified material is filled with a length of 20 m, which effectively relieves the impact force; 2 Externally constructed flexible sealing wall to minimize the damage of personnel and property caused by the destruction of facilities; 3 Internal retaining slurry: 37cm brick closed, 20 m away from the proposed reinforced concrete; 4 reinforced concrete sealed: 800 mm thick; 5 solidified and top material filling: internal injection of 20m long fly ash solidified filling material, When the top is connected, Ma Lisan is injected; 6 flexible protection: the blind alley is reserved for more than 5 m outside the concrete, and the anchor net is set after the blind alley is closed.
(3) Implementation of the closed program. According to the principle of closure of mine danger zone and other key areas and the connection situation of mine production, as well as the actual situation of the need to build or reinforce the closed wall, it is divided into three periods and distributed according to different areas, and a total of 57 new closed roads are constructed. Reinforced and sealed 26 lanes. 1 The first period: the closure and reinforcement of the current roadway, to maximize the scope of the enclosed area, reduce unnecessary lanes, thereby reducing the number of new and reinforced closed walls. The newly built and reinforced closed wall is distributed in the second mining area, the fourth mining area, the first mining area and the fifth mining area. A total of 18 new closed roads are constructed, and 26 closed and 4 coal sliding eyes are reinforced. 2Second time: 43 working under 05 After the end of the mining, the six mining belt lanes, the six mining track lanes, the 2306 rock collection and transportation, the 2304 rock collection and transportation, the 2301 rock collection and transportation, the second mining and drainage road, the 2309 track uphill, the 2309 tape upper mountain, and the 2309 tooth track up the mountain main roadway are reserved. A total of 33 new closed roads were constructed; 3rd time period: after the formation of the return air system in the southern part of the Liucai District, six mining belt lanes, six mining track lanes, 2306 rock collection and transportation, 2301 rock collection and transportation, second mining and drainage roads, 2309 orbital uphill, 2309 tape up the mountain, 230 tooth track up the main roadway.
The second mining hydraulic vehicle house connecting alley, the third mining and one district roadway, the 230 rock collection and the second mining machine road are closed, and a total of 6 roads are closed.
3 Conclusion
Since July 2007, a total of 83 tunnels have been constructed in Baodian Coal Mine, including 57 new roads and 26 roads. Through the implementation of the permanent sealing scheme for large-scale mined-out areas, the quality of the airtightness is ensured, the safety and reliability of the sealing of large-area goafs are effectively improved, the ventilation system is optimized to reduce the air leakage passages, and the natural fire and mine damage are prevented. The occurrence of the mine guarantees the safe production of the mine.
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