Deep thin tungsten ore vein mining method suitable for complex goaf group condition

Abstract

The invention relates to a deep thin tungsten ore vein collection mining method suitable for complex goaf group conditions, which comprises the following steps of: S1, dividing a chamber into three sections, and constructing a discrete separation layer on the middle section of the upper part; s2, a rock drilling layering gate way, a cutting raise, a cutting transverse way and a cutting groove are arranged, and a compensation space is formed for first-time free blasting of the chamber; s3, rock drilling and blasting are carried out in the chamber cutting transverse roadway to form a transverse cutting vertical groove; s4, upward fan-shaped medium-length holes are chiseled in the layered roadway, blasting is carried out by taking the cutting groove as a free surface for the first time of blasting, and it is ensured that the upper layer is ahead of the lower layer by 1-2 rows of holes during the second time of blasting and later blasting, so that step-shaped extrusion blasting ore caving is formed; and S5, loading the ore into a mine car, and transporting the mine car to a separation plant for treatment. According to the method, the upper goaf and the mining middle section are effectively divided by utilizing the reconstructed discrete isolation layer under the goaf group, so that the safety of ore body stoping under the goaf group is guaranteed, ore is efficiently stoped, the ore stoping rate is increased, the ore mining cost is reduced, and the economic benefits of mine enterprises are increased.

Description

Technical Field

[0001] The present application relates to the technical field of ore mining methods, and in particular to a deep thin tungsten ore mining method suitable for mining under complex empty zone group conditions. Background Art

[0002] Influenced by hydrothermal vein-type deposits, black tungsten deposits mostly appear in vein-like form. Steeply inclined thin vein groups are a major feature of tungsten deposits, and many parallel complex veins constitute vein groups. According to engineering geological conditions, the shallow hole ore retention method is considered to be the most effective method. After decades of mining, many parallel voids have been formed in the upper part of most mines. As mining extends, affected by mining stress, dense veins, structural development and other mining environments and geological conditions, the difficulty of mining gradually increases, which greatly limits the recovery rate of deep resources, which is concentrated in the following three aspects.

[0003] First, as mining extends to deeper areas, under the influence of mining stress and void penetration, the stability of the vein group voids formed by the upper shallow hole ore retention method further decreases, and the walls between the voids are extremely easy to collapse, causing the scale of the voids to expand and then trigger strong ground pressure activities, posing a huge safety hazard to deep ore mining.

[0004] Secondly, the deep veins become thicker and the spacing between vein groups becomes smaller. If the traditional shallow hole ore retention method is continued to be used, the rock mass between the veins will be difficult to ensure self-stability, and it is necessary to rely on losing veins to increase the thickness of the mining area wall, which will cause a significant reduction in resource recovery rate.

[0005] Third, under the combined effects of complex empty areas in the upper part and high-stress mining in the deep part, the original shallow hole ore-retaining method of mining continued to be used. The labor intensity of workers did not decrease, and the safety risks of working directly under the roof were further increased, affecting the safe recovery of resources.

[0006] Due to the existence of the above-mentioned major technical difficulties, the resource recovery rate of deep fine-vein tungsten deposits using the shallow hole ore retention method is only 40% to 50%, and the labor safety hazards caused by the continuous deterioration of the mining environment have increased, resulting in a 20% increase in the cost of mining site operations and support, all of which have led to a continuous decline in the economic benefits of tungsten mining companies. Therefore, for the mining of fine-vein tungsten deposits under complex goaf groups, the conventional shallow hole ore retention mining method has serious defects in safety or efficiency. In the absence of ready-made complete sets of technology and experience for reference at home and abroad, new methods must be introduced to solve them. Summary of the invention

[0007] In order to improve the problems of low mining efficiency, low mining safety and high mining cost in deep thin-vein tungsten deposits, the present application provides a deep thin-vein tungsten ore mining method suitable for complex void group conditions.

[0008] The present application provides a method for mining deep thin tungsten ore veins under complex empty zone conditions, which adopts the following technical solutions:

[0009] A deep thin tungsten ore vein mining method suitable for complex empty zone group conditions, comprising the following steps:

[0010] S1. Divide the mine room into three sections, each section is 12-13m high, and build a bulkhead isolation layer at the same position in the upper middle section, the bulkhead isolation layer is at least 20m thick;

[0011] S2. Dig a skylight connecting tunnel at the middle position of the pillar and the transport tunnel at the lower plate of the vein belt, then arrange a pedestrian equipment skylight and dig a rock drilling connecting tunnel and a rock drilling layered tunnel, the layered tunnel is connected to the rock drilling connecting tunnel on the other side of the mine room; arrange a cutting skylight at the end of one side of the mine room, which is connected to the upper middle section transport tunnel, arrange a cutting cross tunnel from the layered tunnel corresponding to the position of the cutting skylight, and form a cutting groove with a medium-deep hole between the cutting skylight and the cutting cross tunnel to form a compensation space for the first free blasting of the mine room;

[0012] S3. Drilling in the horizontal tunnel of the mine room, using the cutting shaft as the blasting free surface, using upward parallel medium-long holes or fan-shaped medium-long holes to blast to form a horizontal cutting vertical groove;

[0013] S4. Drill upward fan-shaped medium-deep holes in the layered lanes and charge them. The first blasting is carried out with the cutting groove as the free surface. In the second and subsequent blasting, ensure that the upper layer is 1 to 2 rows ahead of the lower layer, forming a stepped extrusion blasting and ore collapse;

[0014] S5. After the mine room is squeezed and blasted, it is ventilated and the blasting smoke is blown away. After passing the security inspection, the ore is raked with an electric rake in the electric rake road, and the ore is raked into the short-term retention shaft for ore discharge. It is loaded into the mine car through the ore discharge gate arranged in the vein tunnel, and then pulled by a locomotive to the concentrator for processing.

[0015] Furthermore, before constructing the dispersed isolation layer in step S1, the position selection analysis of the dispersed isolation layer is first carried out to establish four ore body models with different inclinations of 0°, 15°, 45° and 75°; in each of the ore body models, the dip extension length of the goaf is set to 300m, the goaf length is 50m long for a single mining area, and is divided into 6 middle sections. The thickness of the goaf is set to 5m based on the thickness of more than two thin veins, and each type of inclination model has dispersed isolation layers at different positions along the inclination direction.

[0016] Furthermore, 5 of the 6 middle sections are selected as analysis positions of the dispersed isolation layer, and the deformation energy released during the excavation process is compared and analyzed, and the analysis position corresponding to the minimum deformation energy is the selected position of the dispersed isolation layer.

[0017] Furthermore, the thickness of the dispersed isolation layer constructed in step S1 is calculated as follows:

[0018]

[0019] Where:

[0020] h n ——Thickness of effective bulk insulation layer, in m;

[0021] l n ——Roughness coefficient, l n =6.6×10-2d a ;d a is the average diameter of the falling rock, in m;

[0022] N0——rock stratum fall height, unit: m;

[0023] L n ——Thickness of rock layer that may fall, in m;

[0024] F0 / F——the ratio of the falling area, that is, the ratio of the falling area to the exposed area.

[0025] Furthermore, when constructing the dispersed isolation layer in step S1, shallow holes, medium-deep holes and deep holes are coordinated to drill rocks and charge explosives at corresponding positions in the mining area, and small goaf areas are used as blasting compensation spaces, and a single blast or segmented blasting is used to form the dispersed isolation layer.

[0026] Furthermore, the detonation method for constructing the bulk isolation layer adopts a double detonation network of detonating cords and detonating cords, and a slight difference blasting of detonating cord detonators. The blasting sequence is: shallow hole blasting of peach-shaped bottom pillars in the construction area - medium and deep hole blasting of partition walls in the construction area - deep hole blasting of surrounding rocks in the construction area.

[0027] Furthermore, during the entire process of mining and cutting construction, mechanical forced ventilation is used, and fresh air flows into the mining working face from the lower plate along the vein transport tunnel, pedestrian equipment shaft, and layered horizontal tunnel; the blasting smoke is discharged from the gaps in the ore pile, flows back to the upper and middle return air tunnels, and then discharged to the return air shaft.

[0028] Furthermore, before blasting in step S4, stress gauges or wooden slide rules or other ground pressure observation means are arranged in the surrounding rock of the mining area and the rocks of the pillar tunnels to monitor the ground pressure in the mining area to guide safe mining in the mining area.

[0029] Furthermore, after each blast in step S4, the ore output is controlled at 30-40% of the collapsed ore volume, providing compensation space for the next mine room collapse; after all the ore in the mine room has collapsed, the ore is evenly output once again.

[0030] Furthermore, when mining in the mining area, the sections with large, concentrated and complex stresses are selected for mining first, and the sections with small stresses are mined later; between the sections, the upper section is mined first, and the lower section is mined later.

[0031] In summary, the beneficial technical effects of this application are:

[0032] 1. The reconstructed bulk isolation layer under the empty area group is used as a stress isolation zone to effectively separate the upper empty area from the mining middle section, thus ensuring the safety of ore recovery under the empty area group;

[0033] 2. This project developed a high-efficiency mining technology for parallel thin tungsten deposits under the bulk isolation layer to implement high-efficiency mining of the veins. Compared with the original shallow hole ore retention method, the existing high-efficiency mining technology can increase the recovery rate of parallel thin vein group deposits by 45%, and can safely mine deep thin tungsten ores to avoid waste of resources;

[0034] 3. The implementation of safe and efficient mining technology for thin-vein tungsten deposits under complex void groups avoids concentrated exposure of workers under the roof, greatly reduces the mining accident rate, improves the labor efficiency of workers, reduces the labor intensity of workers, and efficiently recovers ore, increases ore recovery rate, reduces ore mining costs, and improves the economic benefits of mining enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of controlling the ground pressure in multiple middle sections by using a dispersed isolation layer in an embodiment of the present application;

[0036] Figure 2 is a cross-sectional view of the stage of segmented rock drilling in an embodiment of the present application;

[0037] Figure 3 is along Figure 2 Schematic diagram of the cross-sectional structure along line AA.

[0038] Description of reference numerals:

[0039] 1. Intermediate pillars; 2. Bulk isolation layer; 3. Partition; 4. Cutting groove; 5. Short-term ore-retention shaft; 6. Funnel; 7. Medium-deep hole; 8. Layered horizontal tunnel; 9. Pedestrian equipment shaft; 10. Rock drilling connecting tunnel; 11. Electric rake road; 12. Transport tunnel along the vein in the lower plate. DETAILED DESCRIPTION

[0040] The technical solution of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0041] The complex mining environment of fine-vein tungsten ore is mainly reflected in three aspects: First, after years of mining activities, a large number of untreated goafs and interlayer rock masses have been formed in the upper part of the mine. The spans of the goafs and the thicknesses of the interlayer rock masses vary greatly, the number is large, and the goaf groups are extremely complex; second, under the combined influence of mining disturbances and ground stress, it is difficult for the interlayer rock masses between the goafs to maintain long-term stability. Due to the lack of effective surrounding rock control technology, the subsequent mining of the upper plate and the top plate of the ore body frequently experience collapse and roof caving, and even a domino effect of collapse of the goaf group occurs; third, as mining extends to deeper areas, the complex mining environment in the upper part seriously threatens the safe recovery of deep resources in the mining area.

[0042] In addition, due to the influence of mining methods and mining costs, as well as the complexity of the void groups, it is unlikely to completely fill the complex void groups formed in the upper part.

[0043] In response to this situation, this application conducts research from the aspects of theoretical analysis, numerical simulation, and technology research and development to master the control law of the stability of the complex void group structure, which can achieve the mechanical separation of the upper void group and the lower mining area, form a mining environment reconstruction technology for fine vein tungsten deposits under complex environments, and provide technical support and safety guarantee for the safe recovery of resources under the void group. The details are as follows.

[0044] The present application embodiment discloses a method for mining deep thin tungsten ore veins under complex empty zone conditions. Figure 1 , Figure 2 and Figure 3 , which comprises the following steps:

[0045] S1. Divide the mine room into three sections, each section is 12 to 13 meters high, and build a bulk isolation layer 2 at the same position in the upper middle section. The bulk isolation layer 2 is at least 20 meters thick. Its purpose is to prevent the upper ground pressure from affecting the lower mining and ensure the safety of the lower operation.

[0046] S2. Dig a skylight connecting tunnel in the middle of the intermediate pillar 1 and the transport tunnel at the foot of the vein belt, and then arrange a pedestrian equipment skylight (or a small bucket plus a pedestrian equipment shaft 9), and dig a rock drilling connecting tunnel 10 and a rock drilling layered horizontal tunnel 8 from the pedestrian equipment shaft 9 to the direction of the mine room. The layered horizontal tunnel 8 is connected to the rock drilling connecting tunnel 10 on the other side of the mine room; dig an electric rake connecting tunnel and an electric rake road 11 in the direction of the intermediate pillar 1 at a height of 3m from the transport tunnel of the pedestrian equipment shaft 9. The spacing between the funnels 6 is 7m, and the specifications of the funnel neck and the bucket are 2.0×2.0m 2 A cutting shaft is arranged at one end of the mine room, which is connected with the upper middle transport level tunnel. A cutting horizontal tunnel is arranged from the layered horizontal tunnel 8 corresponding to the position of the cutting shaft. The cutting shaft and the cutting horizontal tunnel form a cutting groove 4 with a medium-deep hole 7 to form a compensation space for the first free blasting of the mine room.

[0047] S3. Drilling in the horizontal tunnel of the mine room, using the cutting skylight as the blasting free surface, using the upward parallel medium-depth hole 7 or the fan-shaped medium-depth hole 7 to blast to form a horizontal cutting groove, or the cutting groove can also be formed by a small mining method.

[0048] S4. Drill upward fan-shaped medium-deep holes 7 in the layered level tunnel 8 and load them with explosives. The first blasting is carried out with the cutting groove 4 as the free surface. In the second and subsequent blastings, ensure that the upper layer is 1 to 2 rows ahead of the lower layer, forming a stepped extrusion blasting and mine collapse.

[0049] S5. After the mine room is squeezed and blasted, it is ventilated and the blasting smoke is blown away. After passing the security inspection, the ore is raked with an electric rake in the electric rake road 11, and the ore is raked into the ore discharge short retention shaft 5, and loaded into the mine car through the ore discharge gate arranged in the vein laneway, and then the locomotive pulls the mine car to the concentrator for processing.

[0050] Among them, before constructing the dispersed isolation layer 2 in step S1, the position selection analysis of the dispersed isolation layer 2 is first carried out. By combining the effect of the secondary stress field in the mining process, the correlation between the dispersed isolation layer 2 and the inclination of the void area can be obtained by numerical simulation. Specifically, four ore body models with different inclinations of 0°, 15°, 45°, and 75° are established. In order to simplify the calculation process, the scale of the void area is combined with the occurrence of the thin vein group. In each ore body model, the extension length of the goaf is set to 300m (from +150m to -150m, it is planned to be divided into 6 middle sections), and the length of the void area is 50m for a single mining area; the thickness of the void area is combined with the thickness of more than two thin veins and is set to 5m. Each type of inclination model sets dispersed isolation layers 2 at different positions along the inclination direction.

[0051] In order to simplify the calculation, the assumption of small deformation of elastic body is used. According to Saint-Venant's principle, when establishing the model, the unit of the surrounding rock part far away from the ore body is divided into a larger area, and the ore body unit is divided more densely. Each unit is divided into the same size area, which is convenient for calculation. The overall model is divided into 137680 units and 156444 nodes. The selection of rock mass mechanical parameters is the mechanical parameters of the main surrounding rock metamorphic sandstone of Gannan Tungsten Mine. The corresponding bulk density, elastic modulus and Poisson's ratio are ρ1=2.7t / m3, E1=16740MPa, ν1=0.09, and the gravity acceleration is 10m / s2. The constraint condition is to constrain the bottom in the z direction, and the two sides are constrained in the x and y directions respectively. In addition, the upper part of the ore body model needs to be loaded to simulate the deadweight of the surrounding rock in the upper part of the empty area.

[0052] The lower left corner of the model is selected as the coordinate origin, the horizontal right is the positive x direction, the horizontal backward is the y direction, and the vertical upward is the z direction. Calculation is performed in this coordinate system. The specific calculation process is divided into 5 cases for comparative analysis. Specifically, 5 of the 6 middle sections are selected as the analysis positions of the bulk isolation layer, corresponding to the isolation layer positions of 100-120m, 50-70m, 0-20m, -50--30m, and -100--80m, respectively. The deformation energy released during the excavation process is compared and analyzed through the above 5 cases, and the analysis position corresponding to the minimum deformation energy is the selected position of the bulk isolation layer 2.

[0053] According to the analysis results, the best support point of the void formed by the horizontal ore body is located in the middle of the void. As the inclination of the ore body increases, the best position of the bulk isolation layer 2 moves from the middle of the void to the lower part. When the ore body becomes steeply inclined, the best support position of the void formed after mining is located in the lower part of the void. According to the calculation results of the comprehensive deformation energy and its ratio, the amplitude of the change in the best position of the bulk isolation layer 2 is weakened when the void changes from inclination to steep inclination (concentrated in the middle and lower parts), but it still plays a key supporting role in the void. Therefore, for the mining of ore bodies under steeply inclined thin vein groups, the bulk isolation layer 2 should be set at the lower part of the void group, and the bulk waste rock filling or blasting of the surrounding rock at a certain height at the bottom of the void to form a piled bulk isolation layer 2 can effectively control the displacement of the upper and lower plates, slow down the shock wave caused by the instability of the void, and is suitable for the actual engineering situation of the thin vein empty field method for mining tungsten mines.

[0054] Therefore, by constructing an ore body model for analysis and calculation, the location for setting up the dispersed isolation layer 2 with the smallest overall deformation performance and the best supporting effect can be selected. The key middle section area can be selected along the inclined extension direction of the ore body to construct a stress isolation zone, and the upper void area can be effectively divided. Under the support of the isolation layer, the subsequent overall deformation energy of the upper and lower parts of the void area can be minimized, thereby achieving effective control of the overall ground pressure activity of the void area, and can also effectively control the structural cost and the control effect of the overall ground pressure activity of the void area.

[0055] Furthermore, during specific mining, the thickness of the bulk isolation layer 2 constructed in step S1 is calculated as follows:

[0056]

[0057] Where:

[0058] h n ——Thickness of effective bulk insulation layer 2, in m;

[0059] l n ——Roughness coefficient, l n =6.6×10-2d a ;d ais the average diameter of the falling rock, in m;

[0060] N0——rock stratum fall height, unit: m;

[0061] L n ——Thickness of rock layer that may fall, in m;

[0062] F0 / F——the ratio of the falling area, that is, the ratio of the falling area to the exposed area.

[0063] Therefore, by calculating the effective thickness of the dispersed isolation layer 2, the construction of the dispersed isolation layer 2 can be effectively controlled to ensure that the dispersed isolation layer 2 exerts the maximum effect.

[0064] In addition, when constructing the bulk isolation layer 2 in step S1, shallow holes, medium-deep holes 7, and deep holes are coordinated to drill rocks and charge explosives at corresponding positions in the mining area, and small goaf areas are used as blasting compensation spaces. The compensation coefficient is controlled at more than 21%, and the bulk isolation layer 2 is formed by one-time blasting or segmented blasting.

[0065] During the specific operation, the depth of the blastholes is different when drilling rocks at different locations. Generally, three types of blastholes with different apertures are used: Φ42mm, Φ60mm, and Φ100mm.

[0066] (1) Shallow hole: The hole diameter is Φ42mm and the length is 1 to 2m. The YSP-45 pneumatic rock drill is used for rock drilling. The drilling site is a peach-shaped pillar in the shallow hole ore retention method. The explosive is 2# rock emulsion explosive roll.

[0067] (2) Medium-deep holes: The hole diameter is Φ60 mm and the length is 5 to 15 m. The rock drilling is carried out using a YGZ90 rail-type independent rotary rock drill. The rock drilling site is located in the wall between parallel stopes of the shallow hole ore retention method. The explosive used is porous granular viscous ammonium oil explosive.

[0068] (3) Deep hole: The hole diameter is Φ100 mm and the length is 15 to 30 m. The drilling is carried out using a KQJ-100B down-the-hole drill rig. The drilling site is located in the upper and lower surrounding rocks of the shallow hole ore retention method mining area. The explosive is porous granular viscous ammonium oil explosive.

[0069] The detonation method uses a composite detonation network of detonating tubes and detonating cords, and a micro-difference blasting of detonating tube detonators. The specific detonation method is: a single detonating tube millisecond detonator and a single detonating cord enter the hole, a branch detonating cord is used outside the hole to overlap with each detonating cord in the hole, and a detonating tube detonator of the same section as the hole is tied at both ends for detonation. The hole detonating tubes are evenly tied around the main detonating cord, and the DBG-2 type detonating tube trigger triggers and detonates two parallel 20-minute long-delay detonators, and double detonating cords are used for detonation. The blasting sequence is: shallow hole blasting of peach-shaped bottom pillars in the construction area - medium-deep hole 7 blasting of the partition wall in the construction area - deep hole blasting of the surrounding rock in the construction area.

[0070] In addition, in step S2, referring to Figure 2 and Figure 3 In a mining example, the section of the skylight connecting tunnel is 2.0×2.3m 2 , pedestrian equipment well 9 section 1.8×3.5m 2 , rock drilling connection tunnel 10 section 2.5×2.5m 2 , rock drilling layered horizontal tunnel 8 sections 2.5×2.5m 2 , electric rake road 11 section 2.0×2.2m 2 , cutting the section of the patio 1.8×3.0m 2 , cutting cross-tunnel section 2.5×3.0m 2 .

[0071] And, in step S3, after the cutting groove is formed, a YGZ-90 drill is used in the layered horizontal tunnel 8 to drill upward fan-shaped medium-deep holes with a hole diameter of Φ60mm, a row spacing of 1.2m, and a hole bottom distance of 2.2m. Porous granular viscous ammonium oil explosives are used for blasting, and the explosives are charged with BQF-100 pneumatic chargers. The detonating charges, millisecond difference detonators for detonating tubes, detonating cords, detonating tubes and other non-electric detonating methods are used for detonation. The DBG-2 detonating tube trigger is used to trigger and detonate 2 long-delay detonating tube detonators for 20 minutes (or 4 in parallel and in series for 40 minutes).

[0072] The blasting construction of the bulk isolation layer 2 in the upper middle section can be carried out simultaneously with the first free blasting of the mine room. The second and subsequent blasting of the mine room belongs to extrusion blasting. In order to prevent the blasting seismic waves and shock waves from affecting the facilities in the ore pillars, electric rake road 11, and pedestrian equipment shaft 9, the number of rows should be controlled for each blasting. Each layer can be arranged with 3 to 5 rows. The detonator sections between rows are different, and the same row and section are the same. The upper and lower layers can collapse synchronously. Generally speaking, the upper layer is 1 to 2 rows ahead of the lower layer, forming a "staircase"; and because the mine room belongs to extrusion blasting, the working surface at the end of each layer can also be straight, not ahead, which is conducive to loosening and releasing the ore.

[0073] Moreover, during the whole process of mining and cutting construction, mechanical forced ventilation must be adhered to, and ventilation safety management must be strengthened. When the mine room is mined, since the three layered ends of the caving method are collapsed ore piles, fresh air flows from the lower plate along the vein transportation tunnel 12, the pedestrian equipment shaft 9, and the layered horizontal tunnel 8 into the working face of the mining area, and the blasting smoke is discharged from the gaps in the ore pile, flows back to the upper and middle return air tunnels, and then discharged to the return air shaft. The wind resistance of the ore pile is large, the ventilation conditions are poor, and the ventilation time should be longer.

[0074] In order to better control the ground pressure, in addition to selecting a suitable mining method, a reasonable mining sequence must be used to arrange the ore blocks. Specifically, when mining in the stope, the same middle section should be selected with large, concentrated, and complex stress sections first, and the sections with small stress should be mined later; between the middle sections, the upper middle section should be mined first, and the lower middle section should be mined later. In addition, after each blast in step S4, the ore output is controlled at 30-40% of the ore collapse, in order to loosen the ore pile on the working face and provide compensation space for the next mine room to squeeze the ore collapse; after all the ore in the mine room has collapsed, the ore is evenly discharged at one time.

[0075] And because the present application mines the block ore back and forth by extrusion blasting, part of the ore volume needs to be released after each collapse to loosen the ore pile and provide compensation space for the next extrusion blasting. Since there is no goaf after the mine room blasting, the stress of the mining area is released, and the ore pile supports the upper and lower surrounding rocks. The main form of the mining area ground pressure is the impact ground pressure caused by the bottom structure of the ore block such as the electric rake road 11, the roof of the lower plate along the vein transport lane 12 sinking and slabs, and the collapse of the upper middle section of the bulk isolation layer 2. Therefore, before blasting in step S4, stress gauges or wooden slides and other ground pressure observation means should be arranged in the rocks of the mining area surrounding rocks and the pillar laneways to monitor the ground pressure in the mining area to guide the safe mining of the mining area.

[0076] Unless otherwise defined, the technical terms or scientific terms used in this application should be understood by people with ordinary skills in the field to which this application belongs. The words "first", "second", "third" and similar words used in the specification and claims of this application do not indicate any order, quantity or importance, but are only used to distinguish different components. "One" or "one" and similar words do not indicate a quantitative limit, but indicate that there is at least one. "Include" or "comprise" and similar words mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0077] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for mining deep thin tungsten ore veins under complex empty zone conditions, characterized in that: The following steps are involved: S1. Divide the mine room into three sections, each section is 12-13m high, and build a bulkhead isolation layer at the same position in the upper middle section, the bulkhead isolation layer is at least 20m thick; S2. Dig a skylight connecting tunnel at the middle position of the pillar and the transport tunnel at the lower plate of the vein belt, then arrange a pedestrian equipment skylight and dig a rock drilling connecting tunnel and a rock drilling layered tunnel, the layered tunnel is connected to the rock drilling connecting tunnel on the other side of the mine room; arrange a cutting skylight at the end of one side of the mine room, which is connected to the upper middle section transport tunnel, arrange a cutting cross tunnel from the layered tunnel corresponding to the position of the cutting skylight, and form a cutting groove with a medium-deep hole between the cutting skylight and the cutting cross tunnel to form a compensation space for the first free blasting of the mine room; S3. Drilling in the horizontal tunnel of the mine room, using the cutting shaft as the blasting free surface, using upward parallel medium-long holes or fan-shaped medium-long holes to blast to form a horizontal cutting vertical groove; S4. Drill upward fan-shaped medium-deep holes in the layered lanes and charge them. The first blasting is carried out with the cutting groove as the free surface. In the second and subsequent blasting, ensure that the upper layer is 1 to 2 rows ahead of the lower layer, forming a stepped extrusion blasting and ore collapse; S5. After the mine room is squeezed and blasted, it is ventilated and the blasting smoke is blown away. After passing the security inspection, the ore is raked with an electric rake in the electric rake road, and the ore is raked into the short-term retention shaft for ore discharge. It is loaded into the mine car through the ore discharge gate arranged in the vein tunnel, and then pulled by a locomotive to the concentrator for processing.

2. The deep thin tungsten ore mining method applicable to complex empty zone group conditions according to claim 1 is characterized in that: Before constructing the dispersed isolation layer in step S1, the position selection analysis of the dispersed isolation layer is first carried out to establish four ore body models with different inclination angles of 0°, 15°, 45° and 75°; in each of the ore body models, the inclination extension length of the goaf is set to 300m, the length of the goaf is 50m long for a single mining area, and is divided into 6 middle sections. The thickness of the goaf is set to 5m based on the thickness of more than two thin veins, and each type of inclination model sets dispersed isolation layers at different positions along the inclination direction.

3. The deep thin tungsten ore mining method applicable to complex empty zone group conditions according to claim 2 is characterized in that: Five of the six middle sections are selected as analysis positions of the bulk isolation layer, and a comparative analysis is performed on the deformation energy released during the excavation process. The analysis position corresponding to the minimum deformation energy is the selected position of the bulk isolation layer.

4. The method for mining deep thin tungsten ore veins under complex empty zone conditions according to claim 1 is characterized in that: The thickness of the dispersed isolation layer constructed in step S1 is calculated as follows: Where: h n ——Thickness of effective bulk insulation layer, in m; l n ——roughness coefficient, d a is the average diameter of the falling rock, in m; N0——rock stratum fall height, unit: m; L n ——Thickness of rock layer that may fall, in m; F0 / F——the ratio of the falling area, that is, the ratio of the falling area to the exposed area.

5. The deep thin tungsten ore mining method applicable to complex empty zone group conditions according to claim 1 is characterized in that: When constructing the bulk isolation layer in step S1, shallow holes, medium-deep holes and deep holes are coordinated to drill rocks and charge explosives at corresponding positions in the mining field, and small goaf areas are used as blasting compensation spaces. The bulk isolation layer is formed by one-time blasting or segmented blasting.

6. The method for mining deep thin tungsten ore veins under complex empty zone conditions according to claim 5 is characterized in that: The detonation method for constructing the bulk isolation layer adopts a double detonation network of detonating tubes and detonating cords, and a slight difference blasting of detonating tube detonators. The blasting sequence is: shallow hole blasting of peach-shaped bottom pillars in the construction area - medium and deep hole blasting of partition walls in the construction area - deep hole blasting of surrounding rocks in the construction area.

7. The method for mining deep thin tungsten ore veins under complex empty zone conditions according to any one of claims 1 to 6, characterized in that: During the entire process of mining and cutting construction, mechanical forced ventilation is used, and fresh air flows into the mining working face from the lower plate along the vein transport tunnel, pedestrian equipment shaft, and layered horizontal tunnel; the blasting smoke is discharged from the gaps in the ore pile, flows back to the upper and middle return air tunnels, and then discharged to the return air shaft.

8. The method for mining deep thin tungsten ore veins under complex empty zone conditions according to any one of claims 1 to 6, characterized in that: Before blasting in step S4, stress gauges or wooden slide rules or other ground pressure observation means are arranged in the surrounding rock of the mining area and the rocks of the pillar tunnels to monitor the ground pressure in the mining area to guide safe mining in the mining area.

9. The method for mining deep thin tungsten ore veins under complex empty zone conditions according to any one of claims 1 to 6, characterized in that: After each blast in step S4, the ore output is controlled at 30-40% of the collapsed ore volume, providing compensation space for the next mine room collapse; after all the ore in the mine room has collapsed, the ore is evenly output once again.

10. The method for mining deep thin tungsten ore veins under complex empty zone conditions according to any one of claims 1 to 6, characterized in that: When mining in the stope area, the sections with large, concentrated and complex stresses in the same middle section shall be mined first, and the sections with small stresses shall be mined later; between the middle sections, the upper middle section shall be mined first, and the lower middle section shall be mined later.

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