1 Work surface overview
Baijigou South Fourth 4421 (c) in the Southern face 4 Mining fourth stage, the coal mining coal layer is a layer 2, a large structural change seam. The remaining thickness of the coal seam in the northern part of the track is 15.40m. There is a layer of pinch in the coal seam. There are two layers of pinch in the area. The average thickness of the coal seam under the pinch is 1.80m. The inclined face length of 127m, seam angle 9 Â°, the top seam directly off the top of a metal mesh, a direct substrate for the solid coal. According to the excavation and mining geological data, the geological structure of the working face is simple, without faults and folds.
2 Roadway construction and support method
According to the provisions of the "4421 (three) Tunneling Operation Regulations", firstly, the small section cut-eye roadway is excavated along the top line with the track center line as the standard, and then the wide-section roadway is expanded. When excavating the large section and cutting the eye, it is artificially divided into the coal side and the coal pillar side. The normal work is to first carry out the construction of the large section (the side of the coal pillar). After the large section has finished the work sequence of drilling, shooting, shooting, and shed, it will be inspected and strengthened. Then, the excavation construction of the small section (coal side) is carried out, and the cycle is repeated, and the spacing between the two sections is required to be not less than 10 m. The support method is to lay the metal net after each shot, and then back the slab beam of the gang and the top, then pick the front sill, and after the knocking on the top, the upper sill will be temporarily supported, then Out of the shed. After excavating the large-section roadway 10m away from the transport channel, it is 1.10m along the two sides of the track center line, and the small metal pillars are used to stabilize the top of the roadway.
3 Ways to achieve rapid tunneling
(1) Arrange the continuation plan reasonably to ensure that the open-cut construction is carried out in order. The succession plan formed by the fully mechanized mining face is roughly divided into three types. One is to first excavate the installation passage, small cut-eye roadway, and other transportation and return air-slots and small-cut tunnels, and then expand the large-cut roadway; the second is to first excavate the transportation and return airway. , and then dig the installation passage, small cut-off, large-cut roadway; the third is to first dig out the installation passage, small cut-off, large-cut roadway, and then transport, return wind through the channel. According to the comparison of the construction sequence methods, the second construction sequence is more scientific. 1Because the Yunxiang roadway has been formed, the belt can be transported in the transport slot, and the coal can be directly entered into the coal bunker through the belt; 2The installation passage and the small cut-eye roadway are top-down due to the small section and small coal volume. The method of excavation, the large-cut tunneling roadway adopts a bottom-up construction method due to the large amount of coal, and can fully utilize the 40T slipper and the friction strut used for the excavation installation passage and the small-cut tunnel; 3 pedestrian transportation safety Convenient, small cut-off and transportation through the channel, the material is transported from top to bottom, and carried out in the small cut-ey roadway, the coal is transported out by the transport lane, ensuring the safety of the behavioral transport; 4 ventilation It is more reasonable, and the small cut-eye and the transportation pass through the roadway form a natural ventilation system to ensure that the gas concentration is within the specified limits.
(2) Shallow eye-opening, deep grooving, and timely erecting brackets. Since the hardness coefficient of coal is 3.8 or more under the false roof of the metal mesh, it is difficult to increase the tunneling speed according to the conventional blasthole depth of 0..7m and the circulating footage of 0.6m. Under this circumstance, a drilling method with a bottom drilling depth of 1.4 m, a groove depth of 0.9 m, and a depth of 0.7 m of the top eye was proposed. After the gun was released, although the top coal body did not fall, after the vibration, the coal body was loose, and after the top coal was removed with a sharp brazing, the first shed was set up, and the empty roof distance was within the specified range. Then, continue to remove the top coal support second frame, from which it can be found that each cycle footage is 1.20m. The three-cycle footage of each section of the shift can reach 7.20m.
(3) Make full use of working hours to ensure reasonable excavation of the cut-and-eye section. According to the "4421 (three) excavation work regulations", the distance between the large and small sections should be kept at least 10m, but the spacing should not be too large, so that after the large section is finished, the eye will be water (coal) The drill is moved to a small section to continue to drill. At this time, some people cleared the shed and shed in time after the shot was released. After the large-section shed and maintenance work, the preparation of the small section was completed. Work, and the large section side to do the preparation before the shot. This cycle speeds up the tunneling speed.
(4) Strengthen the maintenance of mechanical and electrical equipment and reduce mechanical accidents. According to the actual situation of opening the roadway, the SDP-600 belt conveyor was laid in the transportation lane, and a large set of SGW-40 units was reserved in the return airway to ensure that the working surface was replaced at any time. When the open-cut roadway is tunneled to the middle, the two 40T slides running in parallel are changed into a slipper, a transverse slipper, and then the 40T slipper is extended to the head of the excavation according to the previous excavation method, thus reducing mechanical accidents. The normal operation of the excavation work is guaranteed.
4 Safety management methods
(1) A hollow raft is supported in the open-cut small section roadway and the transportation lane to relieve the pressure on the roof. Before expanding the opening and cutting, firstly install three interlocking hollow rafts at the intersection of the small cutting eye and the transportation roadway to prevent the roof from sinking due to the excessive empty roof area; the hollow raft in the opening 20m It is located in the middle of the open cut, with a spacing of 6.0m. The remaining section of the raft is set at 1.10m from the centerline of the small section and the spacing is maintained at 8.0m. In the case of a large pressure, the spacing of the hollow raft is reduced. At the distance of 20m from the return, the distance between the hollow rafts is kept at 6.0m, and a hollow raft is supported at the intersection of the return air duct and the open cut roadway.
(2) The maintenance of the shed and the supporting point column is carried out on the erected gold-wood hybrid bracket. 4421 (3) The working face is open to the eye. Due to the pressure on the boundary line of the South 2nd and 4th mining areas, due to the influence of the coal pillar pressure, many of the canopy beams are crushed and fractured. phenomenon. On the one hand, the point column was supported for maintenance, and many point poles with incorrect mountain angles were modified. On the other hand, the 2.63m metal steel beam and 2.80m friction metal pillars were used for shed processing and along the track. The center line supports a row of point columns for maintenance, and all the support points are â€œdressed with lacesâ€. The expansion and the bottoming were carried out for the individual height and side sill width caused by the large roof pressure and side pressure. This series of measures ensures a relatively stable roof pressure.
(3) The umbrellas and â€œlandslide coalâ€ of the open-cut roadway were treated to provide advanced maintenance for the small-cut roadway. When digging and opening the large and small sections of the roadway, the roof is broken and the pressure is high, resulting in more umbrellas and â€œsliding coalâ€. To this end, the wooden brackets supported before the shots are first reinforced. After the shots are fired, the tops of the knockouts are promptly applied. The sharply bracing is used to remove the umbrellas and the coals with larger cracks, and the â€œlandslide coalâ€ is crushed and cleaned, and then Dot column maintenance, and then carry out other work. For the small-cut tunnel, the pillars are supported under the five shed beams before the heading for the front to ensure the stability of the roof.
(4) Strengthen the setting of the warning alert to ensure safe construction. Because the open-cut roadway is divided into large and small sections, it is the top priority of safety work. On the one hand, before the shot, the stability of the bracket should be checked first, and the individual brackets should be reinforced. The soft coal area should be lightly drilled, the medicine is less loaded, and the vibrating gun is placed. On the other hand, the warning is placed 100m before and after the shooting position, and it is strictly forbidden for personnel to enter and then fire the gun, thus ensuring the safe tunneling of the roadway.
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