Deep mining method for steeply inclined ore body with pressure relief

Abstract

This invention discloses a method for deep development of steeply dipping ore bodies by yielding pressure, relating to the field of mining engineering technology. The method includes the following steps: determining the destructive range of the hanging wall wedge pressure on the preparatory development stage; determining the wedge pressure destructive angle based on the destructive range of the wedge pressure; dividing the pressure-bearing zone and the yielding zone during the yielding development stage; arranging the hanging wall haulage roadway within the yielding zone; determining the ore pass dip angle; determining the ore pass upper opening position; determining the ore pass lower opening position based on the ore pass upper opening position and the determined ore pass dip angle; determining a reasonable length for the cross-vein roadway that meets production needs; and determining the position of the footwall haulage roadway based on the determined location of the hanging wall haulage roadway, the reasonable length of the cross-vein roadway, and the ore pass lower opening position. This invention enables the deep development system of steeply dipping ore bodies to yield the effect of the hanging wall wedge pressure, increasing the service life of the development project, while also ensuring the circular transport function of the development system, thus achieving normal mine production.

Description

Technical Field

[0001] This invention relates to the field of mining engineering technology, and in particular to a method for deep development of steeply inclined ore bodies with pressure relief. Background Technology

[0002] In underground mining of steeply dipping metal ore bodies, a ring haulage system is typically employed, consisting of hanging wall and footwall haulage roadways along the vein and through-vein roadways. When the mining depth reaches a certain point, the hanging wall haulage roadways located in the surrounding rock become exposed to the pressure of the hanging wall wedge-shaped body. The degree of wedge-shaped body pressure exposure increases with mining depth, resulting in severe deep-level pressure exposure. This makes roadway excavation and maintenance extremely difficult, seriously affecting the normal production and operation of the mine.

[0003] To reduce the damage caused by wedge-shaped ground pressure to the upper plate development project, high-strength support methods are mainly used during tunnel excavation, including shotcrete mesh + metal arch frames and reinforced concrete arches. After 2-3 years of use, under the immense wedge-shaped pressure, the upper plate transport roadways and the cross-cut roadways near the upper plate gradually deteriorate and become unusable. Repair requires removing the metal arch frames and concrete support layers, clearing the broken surrounding rock at the arch crown and sides, removing floor heaves, and then re-implementing high-strength support. However, many sections still experience continuous deformation and damage under the wedge-shaped ground pressure after secondary support, requiring multiple repairs. The repairs are difficult, and some roadways become severely damaged and unusable after only one or two repairs, seriously affecting the safe operation of the mine. Therefore, there is an urgent need to research a pressure-yielding development method that can both alleviate the wedge-shaped pressure on the upper plate and ensure the needs of circular transport. Summary of the Invention

[0004] The purpose of this invention is to provide a method for deep development of steeply inclined ore bodies by allowing the development project to avoid the enormous pressure exerted by the upper wedge-shaped body, thus ensuring the needs of circular transportation.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] This invention provides a method for deep development of steeply dipping ore bodies with pressure relief, comprising the following steps:

[0007] Step S1: Using field investigation, theoretical research, laboratory experiments, and numerical simulation methods, determine the damage range of the pressure of the upper wedge on the preparation stage development project. Based on the damage range of the upper wedge development project in the preparation stage and the positional relationship of the goaf in the mining stage, determine the pressure damage angle of the upper wedge.

[0008] Step S2: According to the pressure failure angle, divide the pressure-bearing zone and the pressure-yielding zone, and arrange the upper plate along the vein transport roadway in the pressure-yielding zone to relieve the pressure effect of the upper plate wedge.

[0009] Step S3: Determine the length of the cross-vein transport roadway based on the location of the upper platen along the vein transport roadway, the loading length of the straight section of the cross-vein roadway, the radius of curvature at the intersection of the cross-vein roadway and the upper platen along the vein transport roadway, the radius of curvature at the intersection of the cross-vein roadway and the lower platen along the vein transport roadway, and the location of the chute opening.

[0010] Step S4: Determine the dip angle of the ore pass based on the relationship between the pressure failure angle and the dip angle of the hanging wall of the ore body;

[0011] Step S5: Based on the number of sections in the preparation stage and the ore extraction requirements of the lowest section, combined with the ore extraction requirements of each section in the pressure relief and development stage, determine the upper position of the ore pass.

[0012] Step S6: Determine the lower opening position of the chute based on the inclination angle of the chute described in step S4 and the upper opening position of the chute described in step S5.

[0013] Step S7: Determine the location of the lower plate transport roadway based on the length of the cross-vein roadway described in Step S3 and the lower opening location of the chute described in Step S6.

[0014] Preferably, the determination of the pressure failure angle includes the following steps:

[0015] Step A, On-site investigation: Based on the damage to the upper plate structure revealed on-site, the pressure range of the upper plate wedge is preliminarily determined, and the pressure-bearing zone and the pressure-relief zone are divided to provide on-site basis for the numerical simulation of the pressure of the upper plate wedge.

[0016] Step B, Determination of rock mass mechanical parameters: Physical and mechanical parameters of the rock mass are obtained through field sampling and laboratory testing, providing a theoretical basis for numerical simulation;

[0017] Step C, establish a numerical simulation model: Based on the occurrence and physical and mechanical parameters of the actual rock mass, and according to the actual mining conditions, establish a geometric model of the ore body and the hanging wall and footwall surrounding rocks;

[0018] Step D, Numerical simulation analysis: Perform numerical simulation analysis on the model to determine the pressure damage range and influence range of the upper wedge body during each stage of mining;

[0019] Step E, determination of the pressure failure angle: Referring to the failure situation of the hanging wall revealed on site and combining the results of numerical simulation, determine the failure boundary of the pressure of the hanging wall wedge on the hanging wall surrounding rock. Connect the failure boundary point of the pressure of the hanging wall wedge on the hanging wall surrounding rock with the hanging wall boundary point of the upper mining stage. The angle between the line segment formed by connecting the failure zone boundary point and the hanging wall boundary point of the upper mining stage and the horizontal line is the pressure failure angle.

[0020] Preferably, in step S1, the boundary point of the damage zone and the boundary point of the upper plate are connected. The angle between the line segment formed by the boundary point of the damage zone and the boundary point of the upper plate and the horizontal line is less than 90°, which is the pressure failure angle. The upper plate side of the pressure failure angle is the pressure-bearing zone, and the lower plate side of the pressure failure angle is the pressure-relief zone.

[0021] Preferably, the pressure failure range of the upper wedge extends from top to bottom along the dip of the ore body, and the pressure failure angle is 75° to 90°.

[0022] Preferably, when the dip angle of the hanging wall of the ore body is not less than the pressure failure angle, the dip angle of the ore pass is adopted as the dip angle of the hanging wall of the ore body; when the dip angle of the hanging wall of the ore body is less than the pressure failure angle, the dip angle of the ore pass is adopted as the pressure failure angle.

[0023] Preferably, the pressure failure angle is first determined, and the pressure-bearing zone and the pressure-yielding zone are delineated based on the pressure failure angle. Then, the position of the upper plate along the vein transport roadway is determined within the pressure-yielding zone. Next, the length of the cross-vein roadway is determined. Then, the inclination angle of the chute, the position of the upper opening of the chute, and the position of the lower opening of the chute are determined. Finally, the position of the lower plate along the vein transport roadway is determined. While yielding the pressure of the upper plate wedge, the normal annular transport of the upper plate along the vein transport roadway, the cross-vein roadway, the lower plate along the vein transport roadway, and the chute is ensured.

[0024] The present invention achieves the following technical effects compared to the prior art:

[0025] This invention determines the pressure failure angle of the upper wedge based on the pressure failure range of the upper wedge, divides the pressure-bearing zone and the pressure-yielding zone, and arranges the upper haulage roadway along the vein within the pressure-yielding zone. This avoids the upper haulage roadway and the cross-vein roadway being directly subjected to the pressure of the upper wedge, reduces the effect of the upper wedge pressure on the lower haulage roadway and ore through the goaf, improves the stability of the upper haulage roadway, the cross-vein roadway, the lower haulage roadway and the ore, and extends the service life of the development project.

[0026] This invention utilizes a method to determine the ore pass dip angle based on the relationship between the dip angle of the hanging wall and the pressure failure angle of the hanging wall wedge. This method reduces the impact of the hanging wall wedge pressure on the ore pass through the goaf, improving the stability and extending the service life of the ore pass. Furthermore, this method allows for flexible ore pass placement based on the manifestation patterns of ground pressure in the hanging wall wedge, maximizing the advantages of the ore pass in circular transport.

[0027] In this invention, the upper hanging wall along-vein transport roadway, the cross-vein roadway, the lower hanging wall along-vein transport roadway, and the ore pass form a complete ring transport system within the ore body, satisfying the ring transport function within the ore body;

[0028] In summary, the present invention, through the above-described method, not only avoids the damage to the development roadway and chute caused by the ground pressure of the upper wedge body, but also ensures the normal function of the ring transport. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 A schematic diagram of a pressure-relief development method for steeply dipping ore bodies;

[0031] Figure 2 A wedge-shaped model;

[0032] Figure 3 A fictional model of a wedge-shaped body;

[0033] Figure 4 This is a wedge model when y = π and β = π / 2;

[0034] Figure 5 This is a geological profile of the exploration line;

[0035] Figure 6 A diagram showing the geometric dimensions of the ore body model and the distribution of measuring points;

[0036] Figure 7 This is a model of the ore body calculated using the software DDA.

[0037] Among them, 1. Upper hanging wall haulage roadway during the pressure relief development stage; 2. Cross-vein roadway during the pressure relief development stage; 3. Lower hanging wall haulage roadway during the pressure relief development stage; 4. Ore pass during the pressure relief development stage; 5. Upper hanging wall haulage roadway during the preparation stage; 6. Cross-vein roadway during the preparation stage; 7. Lower hanging wall haulage roadway during the preparation stage; 8. Sectional cutting roadway during the preparation stage; 9. Sectional connecting roadway during the preparation stage; 10. Sectional mining access roadway during the preparation stage; 11. Sectional lower hanging wall haulage roadway during the preparation stage; 12. Ore pass during the preparation stage; 13. Mining blast hole; 14. Upper hanging wall haulage roadway during the mining stage; 15. Cross-vein roadway during the mining stage; 16. Lower hanging wall haulage roadway during the mining stage; 17. Loose ore; 18. Loose ore in the goaf; 19. Boundary between the wedge-shaped pressure zone and the pressure relief zone; 20. Upper hanging wall of the ore body; 21. Lower hanging wall of the ore body. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] It should be noted that in this paper, the hanging wall haulage roadway 1 in the pressure development stage, the hanging wall haulage roadway 5 in the preparation stage, and the hanging wall haulage roadway 14 in the mining stage represent the states of the hanging wall haulage roadway in the pressure development, preparation, and mining stages, respectively. The hanging wall haulage roadway 1 in the pressure development stage is the basic framework of the hanging wall haulage roadway, and the basic roadway layout is carried out in this stage. The hanging wall haulage roadway 5 in the preparation stage is a refinement and expansion based on the hanging wall haulage roadway 1 in the pressure development stage. The hanging wall haulage roadway 14 in the mining stage forms the final mining system, namely the hanging wall haulage roadway, based on the hanging wall haulage roadway 1 in the pressure development stage and the hanging wall haulage roadway 5 in the preparation stage, and is used for ore transportation.

[0041] In this article, the cross-vein roadway 2 in the pressure-relief development stage, the cross-vein roadway 6 in the preparation stage, and the cross-vein roadway 15 in the mining stage represent the states of the cross-vein roadway in the pressure-relief development stage, the preparation stage, and the mining stage, respectively. The sloping-opening stage through-vein roadway 2 serves the initial development of the mining area, connecting the hanging wall 20 and the footwall 21 of the ore body. It provides the initial layout for the mining area development and lays the basic framework for the preparation stage through-vein roadway 6 and the mining stage through-vein roadway 15. The preparation stage through-vein roadway 6 refines and improves the mining area roadway network based on the sloping-opening stage through-vein roadway 2, laying the foundation for the mining stage through-vein roadway 15. It is used for ore body zoning, mining block division, equipment or pipeline installation, etc. It not only supports mining but also undertakes some transportation tasks in the early stage, but its intensity and scale are smaller than those in the mining stage. The mining stage through-vein roadway 15 makes full use of the roadway network of the sloping-opening stage through-vein roadway 2 and the preparation stage through-vein roadway 6, integrates and optimizes it, supports actual mining operations, and provides direct services for core tasks such as ore transportation, ventilation and smoke extraction, and equipment maintenance.

[0042] This article describes the different states of the footwall haulage roadways at different stages: 3 in the yielding development stage, 7 in the preparation stage, and 16 in the mining stage. Footwall haulage roadway 3 in the yielding development stage provides basic transportation functions in the early stages of mine development, supporting the subsequent preparation and mining stages. Footwall haulage roadway 7 in the preparation stage, based on footwall haulage roadway 3, has a more refined layout, enabling it to support zoned operations and equipment layout for specific ore blocks. Footwall haulage roadway 16 in the mining stage, based on footwall haulage roadway 7 in the preparation stage, undertakes actual production transportation tasks and is the core of the entire footwall haulage system. Footwall haulage roadway 3 in the yielding development stage has a relatively rough location, providing basic connectivity; footwall haulage roadway 7 in the preparation stage is closer to the ore body and integrated with mining needs; footwall haulage roadway 16 in the mining stage is ultimately arranged around the actual mining area.

[0043] In this paper, ore pass 4 in the yielding development stage and ore pass 12 in the preparation stage represent different stages of the ore passage. Ore pass 4 in the yielding development stage is a vertical transportation channel in the early stage of mining, providing basic services for development projects and mainly meeting the needs of early roadway excavation and waste rock transportation. Ore pass 12 in the preparation stage optimizes the layout and function of ore pass 4 in the yielding development stage, serving the zoning preparation of specific mining blocks. By expanding and modifying ore pass 4 in the yielding development stage, its transportation function is upgraded to support the production needs of the subsequent mining stage.

[0044] like Figure 1 This invention discloses a method for deep development of steeply dipping ore bodies by pressure relief, comprising the following steps:

[0045] Step S1: Using methods such as field investigation, theoretical research, laboratory experiments, and numerical simulation, determine the damage range of the pressure of the upper wedge on the development project in the preparation stage. Based on the relationship between the damage range of the upper wedge development project in the preparation stage and the location of the goaf in the mining stage, determine the pressure damage angle β of the upper wedge.

[0046] Step S2: Based on the determined pressure failure angle β of the upper plate wedge, divide the pressure-bearing zone and the pressure-yielding zone, and arrange the upper plate along the vein transport roadway in the pressure-yielding zone to avoid the pressure action of the upper plate wedge.

[0047] Step S3: Based on the determined location of the upper plate along the vein transport roadway, and taking into account the loading length of the straight section of the cross-vein roadway, the radius of curvature at the intersection with the upper plate along the vein transport roadway and the lower plate along the vein transport roadway, and the location of the chute, determine a reasonable length of the cross-vein roadway.

[0048] Step S4: Determine the dip angle of the ore pass based on the relationship between the pressure failure angle β of the hanging wall wedge and the dip angle α of the hanging wall of the ore body;

[0049] Step S5: Based on the number of sections in the preparation stage and the ore extraction requirements of the lowest section, combined with the ore extraction requirements of each section in the pressure relief and development stage, determine the upper position of the ore pass.

[0050] Step S6: Determine the lower opening position of the chute based on the chute inclination angle determined in step S4 and the upper opening position of the chute determined in step S5.

[0051] Step S7: Based on the length of the cross-vein roadway determined in Step S3 and the lower opening position of the chute determined in Step S6, determine the position of the lower plate transport roadway along the vein.

[0052] This invention clarifies the method for determining the pressure failure angle of the hanging wall wedge. It subdivides each stage into a mining stage, a preparation stage, and a pressure-yielding development stage. Using methods such as field investigation, theoretical research, laboratory experiments, and numerical simulation, the failure range of the hanging wall development project in the preparation stage is determined. Based on the relationship between the failure range of the hanging wall development project in the preparation stage and the location of the goaf in the mining stage, the pressure failure angle β of the hanging wall wedge is determined. A pressure-bearing zone and a pressure-yielding zone are then divided. The hanging wall haulage roadway is arranged within the pressure-yielding zone to avoid the pressure exerted by the hanging wall wedge. Based on the relationship between the dip angle α of the hanging wall and the pressure failure angle β of the hanging wall wedge, the dip angle of the ore pass is determined. Based on the location of the hanging wall haulage roadway, the reasonable length of the cross-vein roadway, and the dip angle of the ore pass, the upper and lower opening positions of the ore pass are determined. Finally, based on the location of the ore pass, the location of the footwall haulage roadway is determined.

[0053] In this invention, the pressure failure angle β of the upper wedge is determined according to the pressure failure range of the upper wedge, and the pressure-bearing zone and pressure-yielding zone are divided. The upper haulage roadway along the vein is arranged in the pressure-yielding zone, which avoids the upper haulage roadway and the cross-vein roadway being directly subjected to the pressure of the upper wedge. This reduces the effect of the pressure of the upper wedge on the lower haulage roadway and chute through the goaf sludge 18, improves the stability of the upper haulage roadway, the cross-vein roadway, the lower haulage roadway and the chute, and extends the service life of the development project.

[0054] The present invention utilizes a method to determine the ore pass dip angle based on the relationship between the dip angle α of the hanging wall and the pressure failure angle β of the hanging wall wedge. This method reduces the pressure exerted by the hanging wall wedge on the ore pass through the goaf loose material 18, improving the stability and service life of the ore pass. Furthermore, this method allows for flexible ore pass placement based on the ground pressure manifestation patterns of the hanging wall wedge, maximizing the advantages of the ore pass in circular transport.

[0055] In this invention, the upper hanging wall along-vein transport roadway, the cross-vein roadway, the lower hanging wall along-vein transport roadway, and the ore pass form a complete ring transport system within the ore body, satisfying the ring transport function within the ore body;

[0056] In summary, the present invention not only avoids the damage to the development roadway and chute caused by the wedge-shaped ground pressure through the above method, but also ensures the normal function of the ring transport.

[0057] It should be noted that the pressure-yielding development method in this invention is applicable to the mining of inclined ore bodies in metallic mines. Steeply inclined ore bodies refer to ore bodies with a dip angle greater than 55°. The ore pass mentioned in this invention serves as a top-down channel. After ore extraction, it passes through the preparatory stage segmented extraction roadway 10 and the preparatory stage segmented footwall transport roadway 11, and is then poured into the ore pass. The ore, aided by its own gravity, is quickly transported to the lowest transport level of the stage. A stage refers to a unit in the ore body divided vertically according to a certain height; each stage represents a vertical height range.

[0058] The main roadways in the mine development system are the hanging wall haulage roadway 1, the hanging wall haulage roadway 5, the hanging wall haulage roadway 4, the hanging wall haulage roadway 3, the hanging wall haulage roadway 7, and the hanging wall haulage roadway 16, which are tunneled along the strike of the ore body. The hanging wall haulage roadway 2 is used to connect the hanging wall haulage roadway 1 and the hanging wall haulage roadway 3, forming a stage ring haulage system.

[0059] When arranging a pass, in addition to considering its dip angle, factors such as the development of joints and fissures in the footwall rock, the particle size, moisture content, viscosity of the ore, the service life of the pass, and the mine's production capacity must be taken into account.

[0060] In this invention, when the dip angle of the hanging wall of the ore body is not less than the pressure failure angle of the hanging wall wedge, the dip angle of the ore pass is the dip angle of the hanging wall of the ore body; when the dip angle of the hanging wall of the ore body is less than the pressure failure angle of the hanging wall wedge, the dip angle of the ore pass is the pressure failure angle of the hanging wall wedge.

[0061] Specifically, in step S1, the range of damage caused by the pressure of the upper wedge to the development project in the preparation stage is determined by using methods such as field investigation, theoretical research, laboratory experiments, and numerical simulation. Based on the relationship between the range of damage caused by the upper wedge in the preparation stage and the location of the goaf in the mining stage, the pressure failure angle β of the upper wedge is determined.

[0062] The on-site investigation revealed damage to the development works during the mining and preparation phases, and the locations of damaged sections in the roadways were statistically analyzed and marked on drawings. Rock mechanics parameter determination involved sampling the ore and rock at the site, processing it into standard specimens, and conducting rock mechanics tests in the laboratory to obtain the physical and mechanical parameters of the rock mass, providing a theoretical basis for numerical simulation. The numerical simulation method involved establishing an orebody model based on the actual rock mass occurrence and mechanical parameters, according to the actual mining conditions, and performing numerical simulation analysis on the model to determine the damage range and influence range of the hanging wall wedge pressure during each stage of mining.

[0063] The method for determining the pressure failure angle β of the hanging wall wedge is as follows: referring to the failure situation of the hanging wall project revealed on site and combining the results of numerical simulation, the failure boundary of the pressure of the hanging wall wedge on the hanging wall surrounding rock is determined. The boundary point of the failure zone is connected with the boundary point of the hanging wall in the upper mining stage. The angle between this line segment and the horizontal line is the pressure failure angle β of the hanging wall wedge.

[0064] In step S2 of this invention, based on the determined pressure failure angle β of the hanging wall wedge, a pressure-bearing zone and a pressure-yielding zone are divided. Using this line segment as the boundary, the hanging wall side is the pressure-bearing zone, and the footwall side is the pressure-yielding zone. The hanging wall transport roadway is arranged within the pressure-yielding zone. The specific arrangement location must comprehensively consider the reasonable length of the cross-cut roadway, the dip angle of the ore pass, and the positions of the upper and lower openings of the ore pass to ensure that the pressure-yielding development project forms a circular transport system. In this invention, the pressure failure range of the hanging wall wedge extends downwards along the dip direction of the ore body, generally with a failure angle β = 75°–90°.

[0065] Based on the pressure-bearing zone and pressure-relief zone determined by the above method, the pressure failure zone of the upper plate wedge body is accurately identified, reducing safety accidents caused by the appearance of wedge body ground pressure. Furthermore, based on the pressure failure zone of the upper plate wedge body, the layout of the upper plate along the vein transport roadway, the cross-vein roadway, the lower plate along the vein transport roadway, and the chute can be rationally planned, thereby avoiding damage to the above-mentioned projects from wedge body ground pressure and extending the service life of the development project.

[0066] In step S3 of this invention, based on the determined location of the upper platen along the vein transport roadway, and taking into account the loading length of the straight section of the cross-vein roadway, the radius of curvature at the intersection of the cross-vein roadway and the upper platen along the vein transport roadway in the pressure relief development stage, the cross-vein roadway and the lower platen along the vein transport roadway in the pressure relief development stage, and the location of the chute, a reasonable length of the cross-vein roadway is determined.

[0067] The ore from the staged mining needs to be loaded into the cross-cutting roadway, which must be longer than the entire train of mine cars. The radius of curvature of the roadway at the intersection of the cross-cutting roadway and the upper hanging wall transport roadway of the yielding development stage, and the radius of curvature of the roadway at the intersection of the lower hanging wall transport roadway of the yielding development stage, must be determined based on the length of the mine cars. The radius of curvature must meet the turning requirements of the mine cars and transport equipment to avoid transportation difficulties or equipment damage due to the radius of curvature being too small. It is necessary to ensure that the mine cars can smoothly turn from the upper hanging wall transport roadway and the lower hanging wall transport roadway of the yielding development stage into the cross-cutting roadway.

[0068] Step S4: Determine the dip angle of the ore pass based on the relationship between the pressure failure angle β of the hanging wall wedge and the dip angle α of the ore body. When the dip angle α of the ore body is not less than the pressure failure angle β of the hanging wall wedge, the dip angle of the ore pass is the dip angle α of the hanging wall; when the dip angle α of the ore body is less than the pressure failure angle β of the hanging wall wedge, the dip angle of the ore pass is the pressure failure angle β of the hanging wall wedge.

[0069] This method of determining the ore pass can reduce the pressure from the upper wedge body on the ore pass through the goaf slab 18, thereby improving the stability and service life of the ore pass. Simultaneously, this method allows for flexible ore pass placement based on the ground pressure manifestation patterns of the wedge body, maximizing the advantages of the ore pass in circular transport.

[0070] Step S5: Based on the number of sections in the preparation stage and the ore extraction requirements of the lowest section, combined with the ore extraction requirements of each section in the pressure relief and development stage, determine the upper position of the ore pass.

[0071] Figure 1 The preparation stage is divided into four sections. In each section, a preparatory stage cutting roadway 8 is made on the hanging wall of the ore body. The cutting roadway is used as the free face. The ore body is expelled from the hanging wall to the footwall through the preparatory stage section mining approach 10. The collapsed ore is loaded into a loader and dumped into the pass through the preparatory stage section mining approach 10 and the preparatory stage section footwall along the vein transport roadway 11. It is transported to the lowest section of the stage and loaded into ore cars in the cross-vein roadway. It is then transported to the main shaft through the pressure relief development stage hanging wall along the vein transport roadway 1.

[0072] The selection of the location of the upper opening of the ore pass should take into account factors such as rock stability and transportation convenience. The location of the upper opening of the ore pass should be selected reasonably according to the actual situation of ore extraction in each section of this stage.

[0073] The segmentation is a further division of the stage along the vertical direction, and each segment can be regarded as an independent mining operation unit. Based on the upper opening position of the ore pass and the dip angle of the ore pass, starting from the upper opening position of the ore pass and extending downward along the dip angle of the ore pass, the intersection of this straight line with the lowest horizontal point of the stage is the lower opening position of the ore pass.

[0074] In step S7 of this invention, the location of the footwall haulage roadway is determined based on the length of the vein-crossing roadway and the location of the ore pass. The footwall haulage roadway should be located within stable rock mass in the footwall, maintaining a certain distance from the footwall boundary and the ore pass entrance to avoid mutual interference between ore mining, loading / unloading, and transportation. Simultaneously, the footwall haulage roadway serves the entire stage and has a long service life; therefore, it is essential to ensure the roadway remains undamaged and operates smoothly.

[0075] The determination of the pressure failure angle of the hanging wall wedge in this invention can be carried out according to the following steps: Step A, field investigation: Based on the failure situation of the hanging wall revealed on site, the range of action of the pressure of the hanging wall wedge is preliminarily determined, and the pressure-bearing zone and pressure-yielding zone are divided to provide field basis for numerical simulation of the pressure of the hanging wall wedge; Step B, rock mass mechanical parameter determination: Through on-site sampling and laboratory testing, the physical and mechanical parameters of the ore body and the surrounding rocks of the hanging wall and footwall are obtained to provide theoretical basis for numerical simulation; Step C, establishment of numerical simulation model: Based on the actual rock mass occurrence and physical and mechanical parameters, Based on the actual mining conditions, establish a geometric model of the ore body and the surrounding rocks of the hanging wall and footwall; Step D, numerical simulation analysis: conduct numerical simulation analysis on the model to determine the pressure damage range and influence range of the hanging wall wedge during each mining stage; Step E, determination of the pressure damage angle of the hanging wall wedge: refer to the damage situation of the hanging wall project revealed on site, and combine the results of numerical simulation to determine the damage boundary of the hanging wall wedge pressure on the hanging wall surrounding rock. Connect the boundary point of the damage zone with the boundary point of the hanging wall in the upper mining stage, and the angle between this line segment and the horizontal line is the pressure damage angle of the hanging wall wedge.

[0076] This invention provides crucial protection against wedge-shaped ground pressure damage to staged development projects (upper footing haulage roadways, cross-cut roadways, lower footing haulage roadways, and ore passes). Damage to these development projects disrupts the normal operation of the ring transport system, preventing the transport of ore mined from each stage to the main shaft, severely impacting normal mine production. Therefore, the stability of staged development projects has a significant impact on mine production. This invention avoids large-scale damage from ground pressure to staged development projects in steeply dipping ore bodies, ensuring safe mine operation and bringing significant economic benefits.

[0077] like Figure 1 As shown, the development project in this invention also includes a preparatory stage segmented connecting roadway 9, ore bulk material 17, and a wedge-shaped pressure zone and pressure relief zone boundary line 19.

[0078] From the present invention Figures 1 to 7 It can be seen that the ground pressure of a wedge-shaped body can be calculated mechanically through a geometric model.

[0079] The geophysical calculation process of the wedge-shaped body in this invention is as follows:

[0080] During modeling, since the stress distribution is the same in every section along the strike direction of the wedge, the spatial problem of the wedge is transformed into a planar problem of elasticity, with the length direction considered as unit 1. The wedge experiences two stress states: its own gravity and the supporting force from the granular material on the upper ore wall. According to the classical Janssen granular pressure theory, in the case of a silo or similar structure with vertical walls, the horizontal pressure of the granular material is proportional to the vertical pressure:

[0081] P xy =KP z (1.1)

[0082] In the formula P z - The average vertical pressure exerted on the bottom of the silo or silo-like material hopper, in Pa;

[0083] P xy - The horizontal pressure exerted on the sidewall of a silo or silo-like material hopper, in Pa;

[0084] K - Lateral pressure coefficient, θ is the internal friction angle of the granular material.

[0085] like Figure 2 As shown, a basic model of a semi-infinite asymmetric wedge is established, with surface AB representing the ground surface, and lengths OA and OB of a1 and a2 respectively. As the mining depth increases, point O extends infinitely along the negative x-axis. When establishing the mechanical model, only the state of constant body force under its own weight ρg is considered, without considering the supporting effect of the collapse pit's loose material on the sidewalls. The angle between ρg and the positive x-axis is γ, and the angles between the two wedge surfaces OA and OB and the x-axis are α and β respectively, with no surface forces acting on them. The boundary conditions are as follows:

[0086]

[0087] General solution of stress

[0088] In polar coordinates, if body force has potential, then there exists a potential function V(r,θ) and body force components f. r f θ The relationship with the potential function V(r,θ) is as follows:

[0089]

[0090] When the physical force is a constant ρg Figure 2 The potential function V of the actual model body force shown is:

[0091] V=-f(ar)cos(π-γ-θ)=ρg(ar)cos(γ+θ) (1.4)

[0092] In the formula, ρ represents the density of the elastomer, in kg / m³.

[0093] g - gravitational acceleration, 9.8 m / s²;

[0094] a - length of the wedge surface, in meters.

[0095] Generally, calculations under body forces are much more complex than those under surface forces. Therefore, the actual model of body forces acting on an elastic body can be transformed into a hypothetical model of the same elastic body problem.

[0096] The stress components of ' are σ r σ θ τ rθ The stress component σ in the fictional model r σ θ τ rθ When solving stress boundary problems using stress as the criterion, if the forces are constant, only the stress function needs to be solved. In a Cartesian coordinate system, if the body forces are negligible, f x =f y =0, the stress function and stress components satisfy equation (1.5). According to the relationship between the polar coordinate system and the rectangular coordinate system in equation (1.6), the relationship between the stress function and stress components in the polar coordinate system can be obtained as equation (1.7).

[0097]

[0098] For solving the elastic stress of a semi-infinite wedge under its own weight, a hypothetical model with zero body forces in polar coordinates is generally constructed. Figure 2 The wedge model can be used to obtain a fictional model. Figure 3 (a) Investigate the relationship between the linear distributed load on the wedge surfaces OA and OB and the polar coordinate variation. Figure 3 The load distribution in (a) can be equivalent to... Figure 3 (b) linear distributed load and Figure 3 The superposition of uniformly distributed loads in (c) will be discussed below. Figure 3 (b) and Figure 3 Solving for elastic stress in (c).

[0099] make Figure 3 The stress functions of the semi-infinite asymmetric wedge problems shown in (a), 3(b), and 3(c) are respectively To satisfy the relationship in equation (1.8), a semi-inverse solution method is used to solve for the solution. After that, I received

[0100]

[0101] Refer to the solution process for elastic stress under the self-weight of a semi-infinite wedge. It can be represented as:

[0102]

[0103] In the formula, A1, B1, C1, and D1 are four constants to be determined.

[0104] The stress components corresponding to polar coordinates can be expressed as:

[0105]

[0106] The boundary conditions for plane strain problems must satisfy the following equation:

[0107]

[0108] On the wedge surface OA (θ = α), the boundary conditions are:

[0109]

[0110] On the wedge surface OB (θ = -β), the boundary conditions are:

[0111]

[0112] Combining equations (1.9), (1.10), (1.11), and (1.12), the constants A1, B1, C1, and D1 can be solved. The solution process utilizes the symbolic computation module sympy in the Python programming language.

[0113]

[0114] According to the stress function shown in equation (1.8) Using equation (1.9), we can obtain Figure 3 The general solution for the stress of the asymmetric wedge shown in (b) under its own weight is:

[0115]

[0116]

[0117] Refer to the solution process for elastic stress under the self-weight of a semi-infinite wedge. It can be represented as:

[0118]

[0119] In the formula, A2, B2, C2, and D2 are four constants to be determined.

[0120] The stress components corresponding to polar coordinates can be expressed as:

[0121]

[0122] On the wedge surface OA (θ = α), the boundary conditions are:

[0123]

[0124] On the wedge surface OB (θ = -β), the boundary conditions are:

[0125]

[0126] Similarly, the constants A², B², C², and D² can be solved. The solution process utilizes the symbolic computation module sympy in the Python programming language.

[0127]

[0128] According to the stress function shown in equation (1.21) Using equation (1.9), we can obtain Figure 3 The general solution for the stress of the asymmetric wedge shown in (c) under its own weight is:

[0129]

[0130] According to the principle of stress superposition, Figure 3 The general solution for the stress of the asymmetric wedge shown in (a) under its own weight is:

[0131] σ r =σ r1 +σ r2

[0132] =2r[A1cosθ+B1sinθ-3C1cos3θ-3D1sin3θ]-ρgrcos(γ+θ)-2A2cos2θ-2B2sin2θ+2C2θ-2D2+ρgacos(γ+θ) (1.32)

[0133] σ θ =σ θ1 +σ θ2

[0134] =6r[A1cosθ+B1sinθ+C1cos3θ+D1sin3θ]-ρgrcos(γ+θ)+2A2cos2θ+2B2sin2θ+2C2θ+2D2+ρgacos(γ+θ) (1.33)

[0135] τ rθ =τ rθ1 +τrθ2

[0136] =2r[A1sinθ-B1cosθ+3C1sin3θ-3D1cos3θ]+2A2sin2θ-2B2cos2θ-C2 (1.34)

[0137] In the case of β = π / 2

[0138] like Figure 4 As shown, when γ=π, the values ​​of the general solutions Ai, Bi, Ci, Di (i=1,2) of the stress of the asymmetric wedge under its own weight are as follows:

[0139]

[0140] From the above formula, the general solution for the stress corresponding to γ ​​= π is:

[0141] σ r =σ r1 +σ r2

[0142] =2r[A1cosθ+B1sinθ-3C1cos3θ-3D1sin3θ]+ρgrcosθ-

[0143] 2A2cos2θ-2B2sin2θ+2C2θ-2D2-ρgacosθ(1.76)

[0144] σ θ =σ θ1 +σ θ2

[0145] =6r[A1cosθ+B1sinθ+C1cos3θ+D1sin3θ]+ρgrcosθ+

[0146] 2A2cos2θ+2B2sin2θ+2C2θ+2D2-ρgacosθ(1.77)

[0147] τ rθ =τ rθ1 +τ rθ2

[0148] =2r[A1sinθ-B1cosθ+3C1 sin3θ-3D1cos3θ]+

[0149] 2A²sin²θ - 2B²cos²θ - C²(1.78)

[0150] This invention discloses multiple technical solutions, but does not provide any contrary technical teachings.

[0151] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A method for deep development of steeply dipping ore bodies using pressure relief techniques, characterized in that, Includes the following steps: Step S1: Using field investigation, theoretical research, laboratory experiments, and numerical simulation methods, determine the damage range of the pressure of the upper wedge on the preparation stage development project. Based on the damage range of the upper wedge development project in the preparation stage and the positional relationship of the goaf in the mining stage, determine the pressure damage angle of the upper wedge. Step S2: According to the pressure failure angle, divide the pressure-bearing zone and the pressure-relief zone, and arrange the upper plate along the vein transport roadway in the pressure-relief zone to relieve the pressure effect of the upper plate wedge. Step S3: Determine the length of the cross-vein transport roadway based on the location of the upper platen along the vein transport roadway, the loading length of the straight section of the cross-vein roadway, the radius of curvature at the intersection of the cross-vein roadway and the upper platen along the vein transport roadway, the radius of curvature at the intersection of the cross-vein roadway and the lower platen along the vein transport roadway, and the location of the chute opening. Step S4: Determine the dip angle of the ore pass based on the relationship between the pressure failure angle and the dip angle of the hanging wall of the ore body; Step S5: Based on the number of sections in the preparation stage and the ore extraction requirements of the lowest section, combined with the ore extraction requirements of each section in the pressure relief and development stage, determine the upper position of the ore pass. Step S6: Determine the lower opening position of the chute based on the inclination angle of the chute described in step S4 and the upper opening position of the chute described in step S5. Step S7: Determine the location of the lower plate transport roadway based on the length of the cross-vein roadway described in Step S3 and the lower opening location of the chute described in Step S6. In step S1, the boundary point of the damage zone and the boundary point of the upper plate are connected. The angle between the line segment formed by the boundary point of the damage zone and the boundary point of the upper plate and the horizontal line is less than 90°, which is the pressure damage angle. The upper plate side of the pressure damage angle is the pressure-bearing zone, and the lower plate side of the pressure damage angle is the pressure-relief zone. The pressure failure range of the upper wedge extends from top to bottom along the dip of the ore body; when the dip angle of the upper wall of the ore body is not less than the pressure failure angle, the dip angle of the ore pass is the dip angle of the upper wall of the ore body; when the dip angle of the upper wall of the ore body is less than the pressure failure angle, the dip angle of the ore pass is the pressure failure angle.

2. The deep pressure-relief development method for steeply dipping ore bodies according to claim 1, characterized in that, The determination of the pressure failure angle includes the following steps: Step A, On-site investigation: Based on the damage to the upper plate structure revealed on-site, the pressure range of the upper plate wedge is preliminarily determined, and the pressure-bearing zone and the pressure-relief zone are divided to provide on-site basis for the numerical simulation of the pressure of the upper plate wedge. Step B, Determination of rock mass mechanical parameters: Physical and mechanical parameters of the rock mass are obtained through field sampling and laboratory testing, providing a theoretical basis for numerical simulation; Step C, establish a numerical simulation model: Based on the occurrence and physical and mechanical parameters of the actual rock mass, and according to the actual mining conditions, establish a geometric model of the ore body and the hanging wall and footwall surrounding rocks; Step D, Numerical simulation analysis: Perform numerical simulation analysis on the model to determine the pressure damage range and influence range of the upper wedge body during each stage of mining; Step E, determination of the pressure failure angle: Referring to the failure situation of the hanging wall revealed on site and combining the results of numerical simulation, determine the failure boundary of the pressure of the hanging wall wedge on the hanging wall surrounding rock. Connect the boundary point of the failure zone of the pressure of the hanging wall wedge on the hanging wall surrounding rock with the boundary point of the hanging wall in the upper mining stage. The angle between the line segment formed by connecting the boundary point of the failure zone and the boundary point of the hanging wall in the upper mining stage and the horizontal line is the pressure failure angle.

3. The deep pressure-relief development method for steeply dipping ore bodies according to claim 1, characterized in that, The pressure failure angle is 75°~90°.

4. The deep pressure-relief development method for steeply dipping ore bodies according to claim 1, characterized in that, First, the pressure failure angle is determined. Based on the pressure failure angle, the pressure-bearing zone and the pressure-yielding zone are delineated. Next, the position of the upper plate along the vein transport roadway is determined within the pressure-yielding zone. Then, the length of the cross-vein roadway is determined. Next, the inclination angle of the chute, the position of the upper opening of the chute, and the position of the lower opening of the chute are determined. Finally, the position of the lower plate along the vein transport roadway is determined. While yielding the pressure of the upper plate wedge, the normal circular transport of the upper plate along the vein transport roadway, the cross-vein roadway, the lower plate along the vein transport roadway, and the chute is ensured.

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