First layer mining method in downward approach filling mining method

Abstract

The present application provides a method for mining the first mining layer in a downward approach filling mining method, which belongs to the field of mining. The mining method includes the following steps: constructing a layered transport tunnel along the direction of the ore body in the first mining layer, dividing the first mining layer into 3n mining approaches perpendicular to the direction of the ore body; taking three adjacent mining approaches as units, the mining approach in the middle is a first-step stope, and the mining approaches on both sides are second-step stopes; first mining and supporting the first-step stope, and during mining, opening at the top of the first-step stope to the adjacent second-step stope roof and constructing an adjacent lane advance support anchor rod arranged along the direction of the ore body, mining and supporting the second-step stope; the length of the adjacent lane advance support anchor rod is greater than the width of the mining approach. The present application performs advance pre-support on the second-step stope while supporting the first-step stope, reducing the continuous cycle of advance pre-support and blasting in the second-step stope, greatly improving mining efficiency, and achieving good support effect.

Description

Technical Field

[0001] The present application relates to the field of mining technology, and in particular to a method for mining the first mining layer in a downward approach filling mining method. Background Art

[0002] In order to ensure mining safety, most extremely fractured, medium-thick or thicker ore bodies are mined using the downward approach filling mining method. When the downward approach filling mining method is used in actual construction, the construction of the first mining layer is particularly critical, which is related to whether the entire approach area can smoothly transfer to the lower layer for continued mining. Under extremely fractured ore rock conditions, the surrounding rock has poor self-stabilization ability. Simple plain shotcrete or shotcrete anchor net support methods cannot effectively support the construction tunnels, making it difficult to ensure their safety and stability, and posing a large safety risk. Although the currently used combined support method of "advanced pre-support + shotcrete anchor net + steel belt + steel arch" can provide safe and stable support for the mining approach of the first mining layer, each mining approach must first be actively pre-supported before construction to ensure its safety during the mining process. As a result, all mining approaches are mined using a cycle of "advanced pre-support + blasting + secondary support of the goaf", which seriously restricts the mining efficiency of the downward approach filling mining method stope and makes it difficult to achieve efficient production. Summary of the Invention

[0003] In view of the technical problems existing in the background technology, the present application provides a method for mining the first mining layer in the downward approach filling mining method, which adopts the method of mining one every two steps first to mine the one-step mining area in the middle, and while supporting the one-step mining area, the second-step mining area is also pre-supported in advance, thereby reducing the continuous cycle of pre-support and blasting in the two-step mining area, and greatly improving the mining efficiency.

[0004] The present application provides a method for mining the first layer in a downward approach filling mining method, comprising the following steps:

[0005] S1. Constructing layered haulage tunnels along the strike of the ore body in the primary mining layer, dividing the primary mining layer into 3n mining approaches perpendicular to the strike of the ore body, where n is an integer greater than or equal to 1;

[0006] S2. Taking the three adjacent mining approaches as a unit, the mining approach located in the middle is a first-step stope, and the mining approaches located on both sides are second-step stopes; first, the first-step stope is mined and supported, and during mining, an opening is opened at the top of the first-step stope toward the roof of the adjacent second-step stope to construct an adjacent tunnel advance support anchor rod arranged along the direction of the ore body, and the second-step stope is mined and supported; the length of the adjacent tunnel advance support anchor rod is greater than the width of the mining approach.

[0007] In the technical solution of the embodiment of the present application, the ore body of the first mining layer is first divided into 3n preset mining routes, and the one-step mining area in the middle is mined first by mining every other two. While supporting the one-step mining area, the second-step mining area is pre-supported in advance, so that the two-step mining area adopts a "blasting + secondary support of the goaf" cycle, which reduces the continuous cycle of pre-support and blasting in the two-step mining area, and greatly reduces the switching frequency of the support device and the blasting device. The number of two-step mining areas is twice the number of one-step mining areas. Compared with the traditional mining method, the mining efficiency of the two-step mining area of ​​the present application is greatly improved, thereby improving the mining efficiency of the entire ore body and increasing production capacity.

[0008] In some embodiments, the external insertion angle of the adjacent tunnel advance support anchor rod is 5°-8°, the length of the adjacent tunnel advance support anchor rod is 2-3m larger than the width of the mining approach, and the distance between adjacent adjacent tunnel advance support anchor rods is 200-300mm.

[0009] In this embodiment, by reasonably setting the parameters of the advance support anchor rods near the roadway, the pre-support strength of the two-step stope is improved, providing favorable conditions for safe and efficient mining of the two-step stope.

[0010] In some embodiments, mining and supporting the one-step mining site specifically include: first constructing an advance round steel anchor rod in the one-step mining site, and then supporting while mining; the support includes sequentially carrying out a first shotcrete spraying, constructing a cement mortar anchor rod, laying a metal mesh, laying a steel belt, a second shotcrete spraying, and laying a steel arch frame in the one-step mining site.

[0011] In this embodiment, the support method of "advanced pre-support + shotcrete net + steel belt + steel arch frame" is used to achieve stable support of the one-step mining site, thereby achieving safe and efficient mining of the one-step mining site under extremely broken ore and rock conditions.

[0012] In some embodiments, mining and supporting the two-step mining area specifically include: mining and supporting at the same time; the support includes sequentially performing a shotcrete spraying, constructing the cement mortar anchor rods, laying the metal mesh, laying the steel belt, a second shotcrete spraying, and laying the steel arch frame in the two-step mining area.

[0013] In this embodiment, on the premise that the two-step mining site has been pre-supported in advance, the two-step mining site is stably supported by the support method of "sprayed anchor net + steel belt + steel arch frame", thereby realizing safe and efficient mining of the two-step mining site under extremely broken ore and rock conditions.

[0014] In some embodiments, several of the first-step stopes are mined simultaneously; and several of the second-step stopes are mined simultaneously.

[0015] In this embodiment, the mining efficiency is greatly improved by mining several one-step stopes and several two-step stopes at the same time.

[0016] In some embodiments, the first-step stope is immediately backfilled after the mining is completed; the second-step stope is immediately backfilled after the mining is completed.

[0017] In this embodiment, by filling the first-step stope immediately after the mining is completed, not only the grouting process of the first-step stope and the second-step stope for advanced pre-support is reduced, but also favorable conditions are provided for the mining of the second-step stope.

[0018] In some embodiments, before performing step S1, it also includes dividing the ore body into panels along the strike of the ore body, mining in panels as units, and constructing panel connecting roads between adjacent panels; constructing extra-vein transport tunnels arranged along the strike of the ore body in the surrounding rock outside the panel; and after completing step S2, it also includes mining the first mining layers of the remaining panels.

[0019] In this embodiment, by reasonably dividing the disk area and reasonably setting different tunnels in the disk area, the production area is reasonably planned, the production system is optimized, and the mining efficiency is improved.

[0020] In some embodiments, a transport lane is arranged between at least one set of adjacent two-step stopes.

[0021] In this embodiment, by arranging the transport road, the transport route of the ore is shortened, which facilitates rapid ore removal and improves mining efficiency.

[0022] In some embodiments, the diameter of the advanced round steel anchor rod is 30-35 mm, the length is 3.0-3.5 m, the circumferential spacing is 250-350 mm, and the external insertion angle is 3°-5°; the thickness of the primary shotcrete is 25-35 mm, and the strength is C15; the cement mortar anchor rod is arranged perpendicular to the wall of the mining access road, the diameter of the cement mortar anchor rod is 15-25 mm, the length is 1.8-2.2 m, and the mesh size is (0.8-1. 2)m×(0.8-1.2)m; the mesh size of the metal mesh is (80-120)mm×(80-120)mm, and the size is (1.8-2.2)m×(0.8-1.2)m; the steel strip is a W-shaped steel strip with a length of 2.0-2.5m, a width of 200-250mm, and a thickness of 4-6mm. The spacing between adjacent steel strips is 0.8-1.2m; the thickness of the secondary sprayed concrete is 25-35mm.

[0023] In this embodiment, by reasonably setting the parameters of different support components, safe support of the mining approach is achieved, providing favorable conditions for safe and efficient mining of the mining approach.

[0024] In some embodiments, step S1 further includes supporting the layered transport tunnel.

[0025] In this embodiment, by supporting the layered transport tunnel, the layered transport tunnel of the first mining layer is guaranteed to be safe and stable for a long time, thereby providing favorable conditions for the mining of the first mining layer.

[0026] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] To more clearly illustrate the technical solution of this application, the following is a brief introduction to the drawings used in this application. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0028] Figure 1 This is a schematic diagram of the layout of the first mining layer in the panel area of ​​the downward approach filling mining method in the embodiment of this application; Figure 1 a is a schematic diagram of the first mining layer with 3n mining routes arranged; Figure 1 Figure b is a schematic diagram of the first mining layer with 3n+1 mining routes arranged;

[0029] Figure 2 This is a full cross-sectional view of the stope in the first step of the embodiment of this application;

[0030] Figure 3 This is a side view of the stope in a step of an embodiment of the present application;

[0031] Figure 4 This is a front view of the support section of the mining approach in the embodiment of the present application;

[0032] Figure 5 A top view of the support section of the mining approach in the embodiment of the present application;

[0033] Figure 6 This is a schematic diagram of the threaded nut overlap structure in an embodiment of the present application;

[0034] Figure 7 for Figure 2 Enlarged view of point A in the middle;

[0035] Explanation of the accompanying reference numerals: 1-layered transport tunnel; 2-mining approach; 3-advanced support anchor rod for adjacent tunnel; 4-advanced round steel anchor rod; 5-cement mortar anchor rod; 6-metal mesh; 7-steel belt; 8-steel arch frame; 9-panel connecting road; 10-surrounding rock; 11-extra-vein transport tunnel; 12-threaded nut overlap structure; 13-transport road; 14-pallet; 21-one-step stope; 22-two-step stope; 81-column; 82-arch ring; 121-T-bolt; 122-nut; 123-small washer; 124-large washer. DETAILED DESCRIPTION

[0036] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0038] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0039] In the description of the embodiments of the present application, the orientation or position relationship indicated by technical terms such as "length", "width", "thickness", "up", "down", "top", and "bottom" is based on the orientation or position relationship shown in the accompanying drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as a limitation on the embodiments of the present application.

[0040] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0041] Most of the extremely broken medium and thick ore bodies are mined by the downward approach filling mining method. The construction of the first mining layer of the downward approach filling mining method is particularly critical. Although the currently used combined support method of "advanced pre-support + shotcrete mesh + steel belt + steel arch frame" can provide safe and stable support for the mining approach of the first mining layer, each mining approach adopts the "advanced pre-support + blasting + goaf secondary support" cycle method for mining, and the mining efficiency is low.

[0042] In order to solve the technical problem that each mining route adopts the cycle mode of "advance pre-support + blasting + secondary support of goaf" for mining, resulting in low mining efficiency, the present application provides a first mining layer mining method in the downward route filling mining method, firstly, the ore body of the first mining layer is divided into 3n mining routes, and the middle one-step mining area is mined first by mining one every two routes, and the second-step mining area is supported while the first-step mining area is supported in advance, which effectively guarantees the stability of the roof of the first-step mining area and the second-step mining area, and ensures that the second-step mining area has a stable roof environment before mining, so that the second-step mining area adopts "blasting + secondary support of the goaf" cycle, reducing the continuous cycle of advance pre-support and blasting in the two-step stope, while greatly reducing the switching frequency of support devices and blasting devices. The number of two-step stopes is twice that of one-step stopes. Compared with traditional mining methods, the construction efficiency of the two-step stope is improved, and the efficient mining of the two-step stope under extremely broken ore and rock conditions is promoted. This design scheme not only improves the reliability of the support effect, but also provides technical guarantee for the efficient implementation of the downward approach filling mining method under extremely broken ore and rock and complex geological conditions. It has broad application prospects and promotion value.

[0043] Please refer to Figure 1-Figure 7 , which is a method for mining the first layer in a downward approach filling mining method provided in an embodiment of the present application, comprising the following steps:

[0044] S1. Construct a layered transport tunnel 1 along the direction of the ore body in the first mining layer, and divide the first mining layer into 3n mining routes 2 arranged perpendicular to the direction of the ore body, where n is an integer greater than or equal to 1. Specifically, Figure 1The X-axis direction is along the strike of the ore body, and the Y-axis direction is perpendicular to the strike of the ore body.

[0045] S2, take three adjacent mining routes 2 as units, the mining route 2 in the middle is the first-step stope 21, and the mining routes 2 on both sides are the second-step stopes 22; first mine and support the first-step stope 21, and when mining, open the top of the first-step stope 21 route to the roof of the adjacent second-step stope 22 and construct several adjacent lane advance support anchors 3 arranged along the ore body direction, and mine and support the second-step stope 22; the length of the adjacent lane advance support anchors 3 is greater than the width of the mining route 2. Figure 1 As shown in a, routes 201 to 203 are a unit, wherein route 202 is a one-step stope 21, and routes 201 and 203 are a two-step stope 22; routes 204 to 206 are a unit, wherein route 205 is a one-step stope 21, and routes 204 and 206 are a two-step stope 22, ..., and so on. The widths of routes 201 to 215 are the same, i.e., the cross-sections are the same; the widths of routes 216 to 230 are the same. Specifically, as Figure 4 and Figure 5 As shown, after completing the blasting and mining of the preset distance in the one-step mine 21, while supporting the goaf of the one-step mine 21, an opening is opened at the top position of the one-step mine 21 to the access roof of the two adjacent two-step mines 22, and an advance support anchor rod 3 for the adjacent tunnel is installed to form the advance pre-support of the two-step mine 22. During the mining process of the two-step mine 22, there is no need for advance pre-support. That is, the one-step mine 21 of this application adopts the cycle mode of "advance pre-support + blasting + goaf secondary support", and the two-step mine 22 adopts the cycle mode of "blasting + goaf secondary support", and the continuous cycle of advance pre-support and blasting is reduced during the mining process of the two-step mine 22. In traditional mining methods, during the mining process of each mining approach 2, it is necessary to first carry out advance drilling construction along the excavation contour line of the mining approach 2 at an interpolated angle toward the front of the arch. After the drilling construction is completed, the advance round steel anchor rod 4 is installed to form advance pre-support. That is, each mining approach 2 adopts a cycle of "advance pre-support + blasting + secondary support of the goaf".

[0046] In the technical solution of the embodiment of the present application, the ore body of the first mining layer is first divided into 3n preset mining routes 2, and the three adjacent mining routes 2 are taken as a unit. The first-step stope 21 in the middle is mined first by mining one every other two. While supporting the first-step stope 21, the two adjacent second-step stopes 22 are mined with advance support anchor rods 3 on the tops of the tunnels. That is, while supporting the goaf of the first-step stope 21, the tops of the second-step stopes 22 are directly supported in advance. Compared with the traditional mining in which each mining route 2 is mined in a cycle of "advance support + blasting + secondary support of the goaf", the advance support anchor rods 3 on the tunnels constructed on both sides of the first-step stope 21 in the present application can provide effective support for the tops of the adjacent second-step stopes 22, ensuring that the adjacent second-step stopes 22 have a stable top environment before mining, so that the second-step stopes 22 can be effectively supported. The stope 22 is carried out in a cyclic manner of "blasting + secondary support of the goaf", which reduces the continuous cycle of advance pre-support and blasting in the two-step stope 22, helps to improve the construction efficiency of the two-step stope 22, and thus greatly improves the mining efficiency; secondly, the two-step stope 22 does not need to carry out a continuous cycle of advance pre-support and blasting, which greatly reduces the switching frequency of the support device and the blasting device (and due to the limited space of the mining access 2, the support device and the blasting device also need to move the support device out of the mining access 2 during the switching process), further improving the mining efficiency; furthermore, the two-step mining method of the present application makes the number of two-step stopes 22 more than the number of one-step stopes 21 (the number of two-step stopes 22 is basically twice the number of one-step stopes 21). Compared with the traditional mining method, the mining efficiency of the two-step stope 22 of the present application is greatly improved, thereby improving the mining efficiency of the entire ore body and increasing production capacity. In addition, the advance pre-support of the two-step stope 22 of the present application is completed during the mining process of the one-step stope 21. Therefore, the distance that the two-step stope 22 advances each time increases, thereby reducing the number of cycles of "blasting + secondary support of the goaf", and further improving the mining efficiency. That is, the present application improves the support and mining efficiency by optimizing the support structure and support method of the first mining layer mining approach 2, and provides strong support for the efficient mining of the first mining layer under extremely broken ore and rock conditions. It is understandable that the one-step stope 21 needs to perform advance pre-support on the two-step stope 22 when supporting the goaf. Although this will increase the mining time of the one-step stope 21, overall, the time shortened by the two-step stope 22 is significantly greater. Comprehensive analysis shows that the method of the present application greatly improves the mining efficiency.

[0047] Furthermore, in the embodiments of the present application, Figure 4As shown, the external insertion angle of the adjacent tunnel advance support anchor rod 3 is 5°-8°, preferably 6°; the length of the adjacent tunnel advance support anchor rod 3 is 2-3m larger than the width of the mining approach 2, and the adjacent tunnel advance support anchor rod 3 is a round steel with a diameter of 30-35mm, and the diameter is preferably 32mm; the distance between adjacent adjacent tunnel advance support anchor rods 3 is 200-300mm. Specifically, the net width of the mining approach 2 is 3m, and the length of the adjacent tunnel advance support anchor rod 3 is 6m.

[0048] In the technical solution of the embodiment of the present application, by reasonably setting the external insertion angle of the adjacent roadway advance support anchor rods 3, the distance between adjacent roadway advance support anchor rods 3, and the length of the adjacent roadway advance support anchor rods 3, the pre-support strength of the second-step stope 22 is improved, the stability of the roof of the second-step stope 22 is ensured, and favorable conditions are provided for the safe and efficient mining of the second-step stope 22. By reasonably controlling the distance between adjacent adjacent roadway advance support anchor rods 3, while achieving stable support for the roof of the second-step stope 22, the excessive density of the adjacent roadway advance support anchor rods 3, which increases the support cost, is avoided.

[0049] Furthermore, in the embodiments of the present application, Figure 2As shown, mining and supporting the first-step stope 21 specifically involves first constructing pre-grooved round steel anchor bolts 4 within the first-step stope 21, followed by simultaneous mining and support. This support includes, in sequence, a primary shotcrete installation, the construction of cement mortar anchor bolts 5, the installation of metal mesh 6, the laying of steel belts 7, a secondary shotcrete installation, and the installation of steel arches 8 within the first-step stope 21. Mining access road 2 is a temporary construction project, and backfilling will be performed immediately after completion of its designed length. Therefore, pre-grooved support can be performed without grouting, and the first-step stope 21 can be mined normally using the "pre-grooved support + shotcrete anchor mesh + steel belts + steel arches" support method. Specifically, at the opening position of the first-step stope 21, an advance drilling construction is first carried out along the interpolated angle outside the excavation contour line to the front of the arch. After the drilling construction is completed, the advance round steel anchor rod 4 is installed to form an advance pre-support; then, mining and supporting are carried out simultaneously. After the preset distance is mined, ventilation and slag removal are immediately carried out, and then the entire section is sprayed with concrete once. After the completion of the spraying of concrete, the drilling construction of the cement mortar anchor rod 5 is carried out. After the cement mortar anchor rod 5 is inserted into the hole, the metal mesh 6 and the steel belt 7 are laid. The steel belt 7 is installed along the first-step stope 2 1 is set in the direction of the steel belt 7 and the cement mortar anchor rod 5, and finally the tray 14 is installed at one end of the cement mortar anchor rod 5 close to the first step mining site 21, so that the tray 14 covers the metal mesh 6 and the steel belt 7, thereby completing the construction of the "spray anchor net + steel belt"; then the secondary spraying concrete operation is carried out to ensure that the surface of the secondary spraying concrete layer is relatively smooth, and the supporting components such as the cement mortar anchor rod 5, the metal mesh 6 and the steel belt 7 are basically not exposed, and the support safety standard is met; finally, the steel arch frame 8 is installed. The steel arch frame 8 includes a group of columns 81 and arch rings 82, and the connection between the columns 81 and the arch rings 82 is provided with a threaded nut overlapping structure 12; the columns 81 and the arch rings 82 are both made of I-beams with a model of 25a. Figure 6 As shown, the threaded nut overlap structure 12 includes a T-bolt 121 and a nut 122. Through holes are provided at the connection between the column 81 and the arch ring 82. The T-bolt 121 passes through the through holes provided in the column 81 and the arch ring 82 and is fixed by the nut 122, thereby realizing a detachable connection between the column 81 and the arch ring 82. A large washer 124 is provided at the contact point between the T-bolt 121 and the column 81; a small washer 123 is provided at the contact point between the nut 122 and the arch ring 82. After the goaf support of the first-step stope 21 is completed, an opening is opened at the top of the first-step stope 21 to the roof of the adjacent second-step stope 22, and an adjacent lane advance support anchor rod 3 is constructed along the strike of the ore body, forming an advance pre-support for the second-step stope 22.

[0050] In the technical solution of the embodiment of the present application, a support method of "advanced pre-support + shotcrete mesh + steel belt + steel arch" is used to achieve stable support of the first-step stope 21, thereby achieving safe and efficient mining of the first-step stope 21 under extremely broken ore and rock conditions. By providing advanced pre-support for the second-step stope 22 during the goaf support process of the first-step stope 21, favorable conditions are provided for the safe and efficient mining of the second-step stope 22. By providing a threaded nut overlap structure 12 at the connection between the column 81 and the arch ring 82, the disassembly and installation of the column 81 and the arch ring 82 are facilitated.

[0051] Furthermore, in the embodiment of the present application, mining and supporting the two-step stope 22 specifically includes: mining and supporting at the same time; the support includes sequentially performing a first shotcrete spraying, constructing cement mortar anchor rods 5, laying metal mesh 6, laying steel belts 7, a second shotcrete spraying, and laying steel arch frames 8 in the two-step stope 22. Specifically, after the second-step mining site 22 is mined for a preset distance, ventilation and slag removal are immediately carried out, and then the entire section is sprayed with concrete once. After the first spraying of concrete is completed, drilling of cement mortar anchor rods 5 is carried out. After the cement mortar anchor rods 5 are inserted into the holes, metal mesh 6 and steel belt 7 are laid. The steel belt 7 is arranged along the direction of the second-step mining site 22, and the steel belt 7 is overlapped with the cement mortar anchor rods 5. Finally, a tray 14 is installed at one end of the cement mortar anchor rods 5 close to the second-step mining site 22, so that the tray 14 covers the metal mesh 6 and steel belt 7, thereby completing the construction of "spray anchor net + steel belt"; then a second spraying operation is carried out to ensure that the surface of the second spraying layer is relatively flat, and that the supporting components such as cement mortar anchor rods 5, metal mesh 6 and steel belt 7 are basically not exposed, meeting the support safety standards; finally, the steel arch frame 8 is installed.

[0052] In the technical solution of the embodiment of the present application, on the premise that the advance pre-support of the two-step mining area 22 has been formed, the stable support of the two-step mining area 22 is achieved through the support method of "sprayed anchor net + steel belt + steel arch frame", thereby realizing safe and efficient mining of the two-step mining area 22 under extremely broken ore and rock conditions.

[0053] Furthermore, in the embodiment of the present application, a plurality of one-step stopes 21 are mined simultaneously; and a plurality of two-step stopes 22 are mined simultaneously.

[0054] In the technical solution of the embodiment of the present application, the mining efficiency is greatly improved by mining several one-step stopes 21 and several two-step stopes 22 at the same time.

[0055] Furthermore, in the embodiment of the present application, the first-step stope 21 is immediately filled after the mining is completed; and the second-step stope 22 is immediately filled after the mining is completed.

[0056] In the technical solution of the embodiment of the present application, by filling the first-step stope 21 and the second-step stope 22 immediately after the mining is completed, not only the grouting process of the advance pre-support of the first-step stope 21 and the second-step stope 22 is reduced, but also favorable conditions are provided for the mining of the second-step stope 22, thereby realizing efficient and safe mining of the second-step stope 22.

[0057] Furthermore, in the embodiments of the present application, Figure 1 As shown, before performing step S1, the ore body is divided into panels along the ore body strike, and mining is carried out in panels as units, with panel connecting roads 9 being constructed between adjacent panels; an off-vein transport tunnel 11 is constructed in the surrounding rock 10 outside the panel along the ore body strike; and after completing step S2, the mining of the first mining layers of the remaining panels is also included. It is understandable that mining and cutting projects such as the main ore transport tunnel and the return air tunnel need to be constructed in advance before mining to ensure the circulation of fresh air flow during the mining process and the smooth transportation of ore. These mining and cutting projects are conventional settings of the downward approach filling mining method and will not be repeated here.

[0058] In the technical solution of the embodiment of the present application, by reasonably dividing the disk area and reasonably setting different tunnels in the disk area, the production area is reasonably planned, the production system is optimized, and the mining efficiency is improved.

[0059] Furthermore, in the embodiments of the present application, Figure 1 As shown, a transport road 13 is arranged between at least one set of adjacent two-step stopes 22. Specifically, the transport road 13 is set in the ore body on one side close to the off-vein transport tunnel 11. The ore is transported to the off-vein transport tunnel 11 through the layered transport tunnel 1, the panel area connecting road 9 and the transport road 13. Figure 1 As shown in a, after the transport road 13 is set, in order to divide the primary mining layer into 3n mining routes 2, the widths of routes 201 to 215 are the same, the widths of routes 216 to 230 are the same, and the widths of routes 216 to 230 are slightly larger than the widths of routes 201 to 215. Figure 1 As shown in b, after the transport road 13 is set, in order to ensure that the width of all mining routes 2 is the same, the route 231 is used as a step stope 21 for mining.

[0060] In the technical solution of the embodiment of the present application, by arranging the transport road 13 between at least one group of adjacent two-step stopes 22, the transportation route of the ore is shortened, which facilitates rapid ore removal and improves mining efficiency.

[0061] Furthermore, in the embodiments of the present application, Figure 2As shown, the diameter of the advanced round steel anchor rod 4 in the first step stope 21 is 30-35mm, the length is 3.0-3.5m, the circumferential spacing is 250-350mm, and the external insertion angle is 3°-5°. Preferably, the diameter of the advanced round steel anchor rod 4 is 32mm, the length is 3m, the circumferential spacing is 300mm, and the external insertion angle is 4°; the thickness of the one-time sprayed concrete of all the mining access roads 2 is 25-35mm, preferably 30mm, and the strength is C15; the cement mortar anchor rod 5 is arranged perpendicular to the wall of the mining access road 2, the diameter of the cement mortar anchor rod 5 is 15-25mm, the length is 1.8-2.2m, and the mesh size is (0.8-1.2)m×(0.8-1.2)m. Preferably, the diameter of the cement mortar anchor rod 5 is 20mm, the length is 2m, and the mesh size is 1m× 1m; the mesh size of the metal mesh 6 is (80-120) mm×(80-120) mm, and the size is (1.8-2.2) m×(0.8-1.2) m. Preferably, the mesh size of the metal mesh 6 is 100 mm×100 mm, and the size is 2 m×1 m. The metal mesh 6 is welded with steel bars with a diameter of 8 mm. The steel strip 7 is a W-shaped steel strip with a length of 2.0-2.5 m, a width of 200-250 mm, and a thickness of 4-6 mm. Preferably, the length of the steel strip 7 is 2 m, the width is 220 mm, and the thickness is 5 mm. The spacing between adjacent steel strips 7 is 0.8-1.2 m, preferably 1 m. In relatively broken areas, the spacing between adjacent steel arches 8 can be appropriately reduced, and the arch ring 82 is processed according to the arch shape of the mining access road 2. The thickness of the secondary shotcrete is 25-35 mm. The distance between adjacent steel arches 8 (ie, the step distance) is 0.8-1.2 m, preferably 1 m.

[0062] In the technical solution of the embodiment of the present application, by rationally setting the parameters of the advanced round steel anchor rods 4, cement mortar anchor rods 5, metal mesh 6, steel belts 7, primary shotcrete, and secondary shotcrete, safe support for the mining approach 2 is achieved, providing favorable conditions for safe and efficient mining of the mining approach 2. By rationally controlling the distance between adjacent steel arches 8, while achieving stable support, overcrowding of the steel arches 8, which would increase support costs, is avoided.

[0063] Furthermore, in the embodiment of the present application, step S1 also includes support for the layered transport tunnel 1. Specifically, at the opening position of the layered transport tunnel 1, an advance drilling construction is first carried out along the interpolated angle outside the excavation contour line to the front of the arch. After the drilling construction is completed, the advance grouting anchor rod is installed to form an advance pre-support, and then the grouting construction is carried out. After the slurry solidifies, the excavation operation of the layered transport tunnel 1 is carried out; after the excavation of the layered transport tunnel 1, ventilation and slag removal are immediately carried out, and then a concrete spraying operation is carried out on the entire section; after the concrete spraying is completed, the cement mortar anchor rod 5 is drilled, and the cement mortar anchor rod 5 is inserted into the hole. Then the metal mesh 6 and steel belt 7 are laid. The steel belt 7 is set along the direction of the layered transport tunnel 1. The steel belt 7 is overlapped with the cement mortar anchor rod 5, thereby completing the construction of the "spray anchor mesh + steel belt"; then the secondary spraying concrete operation is carried out to ensure that the surface of the secondary spraying concrete layer is relatively flat, and the supporting components such as the cement mortar anchor rod 5, the metal mesh 6 and the steel belt 7 are basically not exposed, meeting the support safety standard; then the steel arch frame 8 is installed, and the size of the steel arch frame 8 is set according to the size of the layered transport tunnel 1. The pre-grouting anchor rod is a hollow seamless steel pipe. The outer diameter of the pre-grouting anchor rod is 30-35mm, the wall thickness is 5-7mm, the length is 3.0-3.5m, the circumferential spacing is 250-350mm, and the external insertion angle is 3°-5°. Preferably, the outer diameter of the pre-grouting anchor rod is 32mm, the wall thickness is 6mm, the length is 3m, the circumferential spacing is 300mm, and the external insertion angle is 4°.

[0064] In the technical solution of the embodiment of the present application, a combined support method of "advance grouting + full-section sprayed anchor net + steel belt + steel arch frame" is adopted to achieve the support of the layered transport tunnel 1 of the first mining layer. This support method has good active support effect and high support strength, and can ensure the long-term safety and stability of the layered transport tunnel 1 of the first mining layer.

[0065] Please also refer to Figures 1 to 7 According to one or more embodiments of the present application, the present application first divides the ore body of the first mining layer into 3n mining routes 2, and regards the three adjacent mining routes 2 as a unit, and adopts the method of mining one every other two to first mine the one-step mining field 21. While supporting the one-step mining field 21, the two adjacent two-step mining fields 22 are pre-supported in advance, so that the two-step mining field 22 adopts the "blasting + secondary support of the goaf" cycle, which reduces the continuous cycle of pre-support and blasting in the two-step mining field 22, and greatly reduces the switching frequency of the support device and the blasting device. The number of two-step mining fields 22 is twice the number of one-step mining fields 21. This method not only improves the reliability of the support effect, but also greatly improves the mining efficiency of the two-step mining field 22, thereby improving the mining efficiency of the entire ore body and increasing production capacity.

[0066] The present invention is described in detail below through specific examples.

[0067] Example 1

[0068] A method for mining the first mining layer in a downward approach filling mining method comprises the following steps:

[0069] S1, such as Figure 1 As shown in a, a layered transportation tunnel 1 arranged along the direction of the ore body is constructed in the first mining layer, and the first mining layer is divided into 30 mining routes 2 arranged perpendicular to the direction of the ore body.

[0070] S2. Take three adjacent mining approaches 2 as a unit. The mining approach 2 in the middle is a single-step stope 21, and the mining approaches 2 on both sides are two-step stopes 22. Specifically, approaches 201 to 203 form a unit, where approach 202 is a single-step stope 21, and approaches 201 and 203 are two-step stopes 22; approaches 204 to 206 form a unit, where approach 205 is a single-step stope 21, and approaches 204 and 206 are two-step stopes 22, and so on, for a total of 10 units.

[0071] First, the first-step stope 21 is mined and supported. During mining, several advance support anchor bolts 3 arranged along the strike of the ore body are constructed at the top of the approach to the first-step stope 21, extending toward the roof of the adjacent second-step stope 22. The second-step stope 22 is mined and supported. Specifically, the gross cross-sectional dimensions of approaches 201 to 215 are 3.8m×3.3m, and the net cross-sectional dimensions after support are 3.2×3.0m. The gross cross-sectional width and net cross-sectional width of approaches 216 to 230 are slightly wider than those of approaches 201 to 215, and the gross cross-sectional height and net cross-sectional height of approaches 216 to 230 are the same as those of approaches 201 to 215.

[0072] The diameter of the advance round steel anchor rod 4 in the first-step stope 21 is 32 mm, the length is 3 m, the circumferential spacing is 300 mm, the external insertion angle is 4°, and the opening spacing of the advance round steel anchor rod 4 is 2 m. The external insertion angle of the adjacent tunnel advance support anchor rod 3 in the second-step stope 22 is 6°, and the adjacent tunnel advance support anchor rod 3 is round steel with a diameter of 32 mm; the distance between adjacent adjacent tunnel advance support anchor rods 3 is 300 mm, and the length of the adjacent tunnel advance support anchor rod 3 is 6 m (since the width of approach 216-approach 230 is slightly larger than the width of approach 201-approach 215, the length of the advance support anchor rods 3 used in all second-step stopes 22 is the same, reducing the difficulty of manufacturing different advance support anchor rods 3). The estimated time required to mine 30 20-meter-long mining approaches 2 in this application is 360 days. The estimated cost of the advanced round steel anchors 4 and the adjacent tunnel advanced support anchors 3 is 300,000 yuan. Throughout the mining process, both the first-step stope 21 and the second-step stope 22 have good support stability. It is understood that different panels can be mined simultaneously to shorten the time required to mine the entire ore body. The support parameters used during the mining process are determined by the specific mine.

[0073] If mining is carried out according to the traditional method, that is, all mining routes 2 are carried out in a cycle of "advanced pre-support + blasting + secondary support of the goaf", and mining is carried out one by one, first mining the first-step stope 21, and then mining the second-step stope 22. It is estimated that it will take 470 days to mine 30 20-m-long mining routes 2, and the cost of the advanced round steel anchor rods 4 used is estimated to be 370,000 yuan.

[0074] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for mining the first layer in a downward approach filling mining method, characterized in that: The following steps are involved: S1. Constructing layered haulage tunnels along the strike of the ore body in the primary mining layer, dividing the primary mining layer into 3n mining approaches perpendicular to the strike of the ore body, where n is an integer greater than or equal to 1; S2. Take the three adjacent mining approaches as a unit, the mining approach located in the middle as a one-step stope, and the mining approaches located on both sides as two-step stopes; first mine and support the one-step stope, and during mining, open an opening at the top of the one-step stope toward the roof of the adjacent two-step stope to construct an adjacent tunnel advance support anchor rod arranged along the direction of the ore body, and mine and support the two-step stope; the length of the adjacent tunnel advance support anchor rod is greater than the width of the mining approach; the external insertion angle of the adjacent tunnel advance support anchor rod is 5°-8°, the length of the adjacent tunnel advance support anchor rod is 2-3m greater than the width of the mining approach, and the distance between adjacent adjacent tunnel advance support anchor rods is 200-300mm.

2. The first layer mining method in the downward approach filling mining method according to claim 1 is characterized in that: The specific steps of mining and supporting the first-step mining site are as follows: first, advance round steel anchor rods are constructed in the first-step mining site, and then mining and supporting are carried out simultaneously; the support includes spraying concrete once, constructing cement mortar anchor rods, laying metal mesh, laying steel belts, spraying concrete twice, and laying steel arch frames in the first-step mining site in sequence.

3. The first layer mining method in the downward approach filling mining method according to claim 2 is characterized in that: Mining and supporting the two-step mining site specifically include: mining and supporting at the same time; the support includes sequentially carrying out a shotcrete spraying, constructing the cement mortar anchor rods, laying the metal mesh, laying the steel belt, a second shotcrete spraying, and laying the steel arch frame in the two-step mining site.

4. The first layer mining method in the downward approach filling mining method according to claim 3 is characterized in that: Several of the first-step stopes are mined simultaneously; several of the second-step stopes are mined simultaneously.

5. The first layer mining method in the downward approach filling mining method according to claim 4 is characterized in that: After the mining of the stope in the first step is completed, the stope is immediately filled; after the mining of the stope in the second step is completed, the stope is immediately filled.

6. The first layer mining method in the downward approach filling mining method according to claim 1 is characterized in that: Before performing step S1, the process also includes dividing the ore body into panels along the ore body strike, mining the panels as units, and constructing panel connecting roads between adjacent panels; constructing extra-vein transport tunnels arranged along the ore body strike in the surrounding rock outside the panels; and after completing step S2, mining the first mining layers of the remaining panels is also included.

7. The first layer mining method in the downward approach filling mining method according to claim 4 is characterized in that: A transport road is arranged between at least one group of adjacent two-step stopes.

8. The first layer mining method in the downward approach filling mining method according to claim 3 is characterized in that: The diameter of the advanced round steel anchor rod is 30-35mm, the length is 3.0-3.5m, the circumferential spacing is 250-350mm, and the external insertion angle is 3°-5°; the thickness of the one-time shotcrete is 25-35mm, and the strength is C15; the cement mortar anchor rod is arranged perpendicular to the wall of the mining access road, the diameter of the cement mortar anchor rod is 15-25mm, the length is 1.8-2.2m, and the mesh size is (0.8-1.2)m× (0.8-1.2) m; the mesh size of the metal mesh is (80-120) mm × (80-120) mm, and the size is (1.8-2.2) m × (0.8-1.2) m; the steel strip is a W-shaped steel strip with a length of 2.0-2.5 m, a width of 200-250 mm, and a thickness of 4-6 mm. The spacing between adjacent steel strips is 0.8-1.2 m; the thickness of the secondary sprayed concrete is 25-35 mm.

9. The first layer mining method in the downward approach filling mining method according to claim 1 is characterized in that: Step S1 also includes supporting the layered transport tunnel.

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