[0033] The embodiments of the present invention will be described in further detail below in conjunction with the drawings and examples. The following examples are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.
[0034] In the description of the present invention, unless otherwise specified, "plurality" means two or more; the terms "upper", "lower", "left", "right", "inner", "outer" , "Front", "Back", "Top", "Bottom", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating It may also imply that the pointed device or element must have a specific orientation, be configured and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance.
[0035] In the description of the present invention, it should be noted that the terms "installation", "connected" and "connected" should be understood in a broad sense, unless otherwise clearly specified and limited. For example, they can be fixed or detachable. Connected or integrally connected; it can be directly connected or indirectly connected through an intermediary. For those of ordinary skill in the art, the specific meaning of the above-mentioned terms in the present invention can be understood according to specific circumstances.
[0036] Such as Figure 1 ~ Figure 3 As shown, this embodiment provides a method for increasing the initial coal recovery rate of a fully mechanized caving face in an extra-thick seam, which includes the following steps:
[0037] Step 1: Cut an open cut on the solid coal to obtain fully mechanized caving face 1, and arrange drilling equipment and fully mechanized mining equipment in fully mechanized caving face 1;
[0038] Step 2: Use drilling equipment to drill multiple blast holes 3 of different depths in the top coal 2 of fully mechanized caving face 1;
[0039] Step 3: Load explosive into the blast hole 3, detonate the explosive, and blast the top coal 2;
[0040] Step 4: Repeat steps 2 and 3 until the top coal completely collapses.
[0041] Among them, see figure 2 , The multiple blast holes 3 are arranged in a row along the axial direction of the fully mechanized caving face 1, and the depth of each two adjacent blast holes 3 is different.
[0042] The drilling equipment includes a bolt drill and an alloy steel drill bit (not shown in the figure) arranged on the bolt drill. Preferably, the outer diameter of the alloy steel drill bit is 42 mm. The construction of blast hole 3 is carried out with bolt drill rig matching φ42mm alloy steel drill bit, which is safer, faster and more efficient than using traditional chain drill.
[0043] Wherein, the method of loading explosive 7 into the blast hole 3 includes the following steps:
[0044] Use loess 9 to block the first end 5 of the charge main pipe 4;
[0045] From the second end 6 of the charge main pipe 4, sequentially load the explosive 7 and the blasting primer 8 into the charge main pipe 4, and block the second end 6 of the charge main pipe 4 with loess 9;
[0046] Pass the charge main pipe 4 filled with loess 9 and explosive 7 into the blast hole 3 from the blast hole 10 of the blast hole 3, and make the charge main pipe 4 reach the top of the blast hole 3;
[0047] Use loess 9 to block the blasthole opening 10.
[0048] Further, when loading the blasting primer 8 into the main charge of charge 4, an electric detonator 11 is first installed in the main charge of charge 4, and the leg wire of the electric detonator 11 is connected to the gun line 12.
[0049] Further, the way to make the main charge pipe 4 directly reach the top of the blast hole 3 is: butt the top end of the auxiliary pipe with the bottom end of the main charge pipe 4, and push the main charge pipe 4 to the blast hole 3 by pushing up the auxiliary pipe. the top of.
[0050] In this embodiment, the charge main pipe 4 and the auxiliary pipe are both PVC pipes; the fully mechanized mining equipment in this embodiment includes a hydraulic support 14, a shearer 15, a top coal conveyor 16, and a hydraulic support set in the fully mechanized caving face 1. For the terminal bracket 17 in the advanced working surface, the connection and cooperation between the devices adopt the conventional setting methods in the field.
[0051] See figure 1 , The included angle between the axial direction of the blast hole 3 drilled for the first time and the horizontal direction of the top coal 2 in this embodiment is 70°, (that is, the blast hole 3 faces the goaf 70°); the axial direction of the blast hole 3 drilled subsequently Vertical to the horizontal direction of top coal 2. The angle between the axial direction of the blast hole drilled for the first time and the horizontal direction of the top coal is 70°, which is beneficial to expand the blasting pre-cracking range of the top coal during the primary mining.
[0052] Reference Figure 1 ~ Figure 2 In combination with the above steps, this embodiment provides a specific blasting method, including the following steps:
[0053] (1) Cut a cut hole on the solid coal to obtain a fully mechanized caving face, such as figure 1 As shown, a row of blast holes of different depths are drilled on the top coal between the hydraulic support located in the middle and the coal wall of the end support at the end. The blast holes are uniformly oriented toward the goaf at 70°, and each blast hole is installed. With 5 rolls of explosives and 1 power detonator, 10 blast holes are detonated each time, and the charge is forward charge. During the advancing process, blasting and topping are performed according to the above blasting method every 3 cycles.
[0054] (2) When the fully mechanized caving face advances 16m, blast holes of different depths will be constructed again for forced blasting and topping, and one blast hole will be constructed at the gap between the hydraulic supports every other hydraulic support. The blast holes are arranged vertically in the horizontal direction of the top coal. , Each blasthole is equipped with 15 rolls of explosives and 1 generator detonator, 5 blastholes are detonated each time, and the charge adopts forward charging.
[0055] (3) When the fully mechanized caving face advances 18m, blast holes of different depths are constructed again at the above positions for forced blasting and topping, and one blast hole is constructed at the gap between the hydraulic supports every other hydraulic support. Layout in the horizontal direction, each blast hole is equipped with 15 rolls of explosives and 1 generator detonator, and 5 blast holes are detonated each time, and the charge adopts forward charging. After the blasting was completed, the top coal basically collapsed completely.
[0056] Reference image 3 Combining the above steps, when charging a blast hole with a depth of 10 to 17m in this embodiment, first one end of a PVC charge main pipe with an inner diameter of 40mm and a length of 4m is filled with 300mm long loess, and then 14 rolls of gunpowder are loaded from the other end. Then load a roll of blasting primer (when loading the blasting primer, first install an electric detonator in the main charge of the charge, and connect the leg wire of the electric detonator to the 19m long gun wire, and use the joint between the leg wire and the gun wire. Wrap tightly with waterproof tape), and finally put the loess into the other end of the PVC charge main pipe to block the charge main pipe. After the explosive is installed in the main charge, the main charge is penetrated into the blast hole as a whole, and then multiple PVC auxiliary pipes with an inner diameter of 36mm and a length of 4m are connected to each other to push the main charge into the blast hole. The top is tamped hard until the auxiliary tube is pulled out, the main charge of the gunpowder will not slide down, and finally 2000mm long loess is filled in the gun hole.
[0057] This embodiment uses the deep and shallow hole circulation blasting technology to greatly improve the initial coal recovery rate of the fully mechanized caving face in the ultra-thick hard coal seam, and at the same time, innovative methods are used in the process of drilling and charging. Take the 23111 working face and 23107 working face of Xiegou coal mine of 10 million tons level as examples. The thickness of the coal seam is 14m, the coal mining height is 3.6m, and the coal caving height is 11.4m. In the first mining of 23111 working face, deep and shallow holes are aligned The overlying top coal rock mass is disturbed by blasting, forming pre-cracks in the coal rock mass, reducing the integrity and stability of the coal rock mass. When the working face advances 15m before, the top coal partially collapses, and the collapse height is about 7m. As we continued to advance, the top coal basically collapsed, and normal mining and caving began. However, the 23107 working face did not adopt the deep and shallow hole circulation blasting technology. When the working face was advanced for 60m, the top coal began to collapse. From this, it can be calculated that the recovery of coal resources after the deep and shallow hole circulation blasting technology is about : (122×1.41×15×7+122×1.41×45×11.5) = 107,000 tons of coal. If calculated according to the raw coal revenue per ton of coal is 300 yuan/ton, 107,000 tons of coal can be recovered, and the economic benefit is about 32.1 million yuan.
[0058] In the method described in this embodiment, a row of blast holes of different depths are drilled on the top coal between the hydraulic support and the coal wall of the end support, and the top coal is blasted to form artificial artificial rocks in the original rock that is not affected by mining. The fracture zone and the fracture zone simultaneously weaken the interlayer bonding strength of the weak surface in the original rock. With the advancement of the mining face, under the action of the stress field of the mining face, the artificial fissures produced by blasting and the primary fissures with weakened binding force intersect each other in a certain area and expand to the deep and wide parts of the rock mass. Under the influence of mining, the strength of the rock mass decreases significantly with the expansion of artificial fissures and primary fissures, which transforms the difficult-to-fell roof to the fallable roof (increasing the caving ability of the top coal), so as to achieve the early recovery of the broken top coal the goal of.
[0059] To sum up, the method of improving the initial coal recovery rate of the fully mechanized caving face in the extra-thick seam described in this embodiment uses the blast hole blasting technology. After blasting, the integrity of the top coal is destroyed, causing the top coal to collapse completely and greatly Improve the recovery rate of top coal.
[0060] The depths of the two adjacent blast holes in this embodiment are different, that is, the deep blast holes and the shallow blast holes are arranged alternately, and the deep and shallow blast holes are cyclically blasted, so that the top coal in different parts of the top coal can be uniformly blasted, thereby The efficiency of top coal collapse is further improved, and the recovery efficiency of top coal is improved.
[0061] The embodiments of the present invention are given for the sake of example and description, and are not exhaustive or limit the present invention to the disclosed form. Many modifications and changes are obvious to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention, and to enable those of ordinary skill in the art to understand the present invention so as to design various embodiments with various modifications suitable for specific purposes.
