A two-step pillarless short-hole ore drawing and two-step ore drawing backfill mining method

Abstract

The application discloses an inter-column shallow hole ore falling two-step ore-reserved subsequent filling mining method, belongs to the technical field of underground mining, and comprises the following steps: arranging mining preparation engineering; arranging cutting engineering to form a stoping space; dividing a mineral column into an upper disc mineral column and a lower disc mineral column, stoping the lower disc mineral column, and filling after ore drawing; and stoping the upper disc mineral column. According to the scheme, the lower disc mineral column is first stoped and filled to form a support body, and then the upper disc mineral column is stoped, so that the whole goaf is prevented from being exposed, and the possibility that the surrounding rock is destabilized due to the recovery of the mineral column in the high and large goaf is reduced; the filling body replaces the mineral column to bear the roof pressure, so that the amount of the permanent mineral column to be reserved is reduced, and the stoping rate is improved; the goaf is closed in time after filling, the surrounding rock movement is inhibited, and the problem of surface subsidence is avoided; the mineral column is divided according to positions and rock mass stress, and stoping is performed in sequence, the stress superposition risk of synchronous stoping is reduced, and thus the method has high safety.

Description

Technical Field

[0001] This invention belongs to the field of underground mining technology, and in particular relates to a two-step ore retention and subsequent backfilling mining method for shallow hole ore extraction with pillars. Background Technology

[0002] Metal mining has long faced challenges such as poor rock stability, high risk of surface subsidence, and low resource recovery rates. While traditional stope mining methods are suitable for stable rock conditions, as mining scales up, the increased exposed area of ​​the goaf can easily lead to ground pressure instability, surface subsidence, and high pillar recovery dilution rates. Taking shallow-hole stope mining as an example, although it has advantages such as small preparation work and high flexibility, the long-term lack of backfilling in the goaf exacerbates the risk of surrounding rock movement, and stress concentration during pillar recovery can easily cause safety accidents. To control goaf risks, backfilling methods have been gradually promoted. Although this method can reduce surface subsidence, the stope and pillars need to be recovered in stages, leading to problems such as insufficient backfill strength and poor boundary stability during pillar recovery. Especially when the dip angle of the ore body changes significantly, the pressure difference between the hanging wall and footwall is significant, and single pillar recovery can easily cause spalling accidents. Therefore, a mining method that can safely recover pillars between thin ore bodies is needed. Summary of the Invention

[0003] In view of the technical problems existing in the background art, this application provides a two-step ore retention and subsequent backfilling mining method for shallow hole ore extraction with pillars, including: Arrange the preparation work; Arrange cutting work to create mining space; The pillar is divided into the hanging wall pillar and the footing wall pillar. The footing wall pillar is mined and backfilled after the ore is extracted. Mining the hanging wall ore pillar.

[0004] In some embodiments, the process of dividing the pillar into a hanging wall pillar and a footwall pillar, mining the footwall pillar, and backfilling after ore extraction includes: The lower pillar is mined in layers from bottom to top, and shallow-hole blasting is used to remove some ore, leaving some ore as a working platform for continued mining.

[0005] In some embodiments, the preparation and setup process includes: A top pillar is left at the top of the pillar, and a connecting passage between the top pillar and the top of the ore body is excavated below the top pillar. The process of dividing the ore pillar into a hanging wall pillar and a footwall pillar, mining the footwall pillar, and backfilling after ore extraction includes: When mining the lower pillar to half the pillar elevation, personnel enter the mine through a short connecting tunnel excavated from the top pillar connecting tunnel.

[0006] In some embodiments, the process of dividing the pillar into a hanging wall pillar and a footwall pillar, mining the footwall pillar, and backfilling after ore extraction includes: After the lower ore body is mined to completion, ore is extracted in sections and concentratedly, and then the empty areas are filled.

[0007] In some embodiments, the preparation and setup process includes: Excavate a hanging wall transport tunnel along the bottom of the hanging wall of the ore body; The hanging wall pillar includes: A portion of the pillars at the bottom of the hanging wall pillars, near the hanging wall transport roadway, is left unmined as a safety pillar.

[0008] In some embodiments, the preparation and setup process includes: The existing ore extraction roadway at the bottom of the ore pillar is used, wherein the hanging wall transport roadway passes through the ore extraction roadway but is not parallel to the ore extraction roadway, and the hanging wall transport roadway is set at the end of the ore extraction roadway near the hanging wall ore pillar. The hanging wall pillar includes: The ore exit roadway on one side of the hanging wall pillar is expanded and a hanging wall loading chamber is formed.

[0009] In some embodiments, the preparation and setup process includes: An upper hanging wall riser is excavated on the surface of the hanging wall pillar in line with the vertical direction of the ore body, connecting it to the bottom ore extraction roadway. At the same time, the upper hanging wall riser is also connected to the upper and middle ventilation roadway.

[0010] In some embodiments, the preparation and setup process includes: A footwall riser is excavated on the surface of the footwall pillar in accordance with the vertical direction of the ore body. The footwall riser and the hanging wall riser are connected by a top connecting tunnel, which is located at the top of the pillar ore body.

[0011] In some embodiments, the preparation and setup process includes: The existing ore extraction tunnel at the bottom of the ore pillar will be reused; The process of dividing a ore pillar into a hanging wall pillar and a footwall pillar, mining the footwall pillar, and backfilling after ore extraction includes: The ore exit roadway on one side of the footwall pillar is expanded and a footwall loading chamber is formed; The hanging wall pillar includes: The ore exit roadway on one side of the hanging wall pillar is expanded and a hanging wall loading chamber is formed.

[0012] In some embodiments, after the ore extraction roadway is expanded on one side of the footwall pillar and a footwall loading chamber is formed, the process of dividing the pillar into an upper hanging pillar and a lower hanging pillar, mining the lower hanging pillar, and backfilling after ore extraction further includes: Temporary support and reinforcement were carried out in the expanded space.

[0013] This invention provides a two-step mining method for shallow-hole ore extraction with pillars, including: arranging preparatory works; arranging cutting works to form a mining space; dividing the pillars into hanging wall pillars and footwall pillars; mining the footwall pillars and backfilling them after extraction; and mining the hanging wall pillars. In this scheme, the footwall pillars are mined and backfilled first to form a support structure, while the hanging wall pillars are mined later, avoiding the exposure of the entire goaf and thus reducing the possibility of rock instability caused by pillar recovery in high goaf areas; the backfill replaces the pillars to bear the roof pressure, thereby reducing the amount of permanent pillars and improving the recovery rate; the goaf is sealed in time after backfilling to suppress rock movement and avoid surface subsidence; the pillars are divided according to location and rock stress and mined sequentially, reducing the risk of stress superposition during simultaneous mining and avoiding stope collapse due to uncontrolled ground pressure, thus providing a highly safe method for inter-pillar ore extraction.

[0014] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0016] Figure 1 This is a schematic diagram of the basic steps of a two-step ore retention and subsequent backfilling mining method provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the optimized steps of a two-step ore retention and subsequent backfilling mining method with shallow hole ore extraction provided in an embodiment of the present invention regarding sequential mining; Figure 3 This is a schematic diagram illustrating further optimization steps of a two-step ore retention and subsequent backfilling mining method with shallow hole ore extraction in the context of sequential and layered mining, as provided in an embodiment of the present invention. Figure 4 This is a schematic diagram of the filling steps in a two-step ore retention and subsequent backfilling mining method for shallow hole ore extraction provided by an embodiment of the present invention; Figure 5 This is a schematic diagram of the optimized steps for upper pillar mining in a two-step ore retention and subsequent backfilling mining method provided by an embodiment of the present invention. Figure 6This is a schematic diagram of a further optimized step in the hanging wall pillar mining method of two-step ore retention and subsequent backfilling mining provided by an embodiment of the present invention. Figure 7 This is a schematic diagram illustrating the steps of setting up the hanging wall riser in a two-step ore retention and subsequent backfilling mining method using shallow hole ore extraction with inter-column support, as provided in an embodiment of the present invention. Figure 8 This is a schematic diagram illustrating the steps of setting up a footing riser in a two-step ore retention and subsequent backfilling mining method using shallow hole ore extraction with inter-column support, as provided in an embodiment of the present invention. Figure 9 This is a schematic diagram of the steps in a two-step ore retention and subsequent backfilling mining method for expanding and scouring ore roadways provided in an embodiment of the present invention; Figure 10 This is a schematic diagram of the steps of a two-step ore retention and subsequent backfilling mining method for enhanced support provided by an embodiment of the present invention. Detailed Implementation

[0017] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0019] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0020] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0021] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0022] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0023] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0024] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0027] Reference Figure 1A two-step ore-retention and subsequent backfilling mining method for shallow-hole ore cutting with inter-pillars includes the following steps: S101, setting up the preparatory works. Specifically, this refers to excavating transport horizontal tunnels, ventilation shafts, ore chutes, and connecting roadways within the ore body to form a system framework for ore transport, personnel passage, and ventilation. For example, the transport horizontal tunnels are arranged along the strike of the ore body in the footwall surrounding rock, or existing roadways from the stope mining can be reused and partially widened to accommodate the working range of the inter-pillars; the ventilation shafts connect the upper and lower levels and link to the return air roadways, while the ore chutes are vertically distributed at the bottom of the inter-pillars to ensure that the blasted ore can fall into the transport horizontal tunnels by gravity; the purpose of this step is to establish a basic channel network for mining operations, providing working space and conditions for subsequent mining operations.

[0028] S102. Arrange the cutting works to form a mining space. Specifically, this step involves excavating a cutting ramp and a cutting incline at the bottom of the inter-pillar of the ore body, and forming an initial free face through shallow-hole blasting. For example, the cutting incline ascends vertically along the centerline of the inter-pillar of the ore body, with the same height as the inter-pillar, while the cutting ramp horizontally connects the mining space to the ore pass. This process is to create sufficient working space and guide the flow path of the caving ore, releasing the stress of the ore body through directional blasting, making it easier for subsequent ore to separate along the weak face, thereby reducing blasting energy loss and improving ore extraction efficiency.

[0029] S103. Divide the pillars into hanging wall pillars and footwall pillars. Mine the footwall pillars and backfill them after ore extraction. Specifically, based on the difference in ore body dip angle and surrounding rock stability, the pillars are divided into two categories according to their distance from the hanging wall and footwall boundaries. For example, the footwall pillars, being close to the transport level and subject to less ground pressure, are preferentially mined using shallow-hole drilling and blasting. Drilling is performed using a YT-28 drilling rig, with a hole depth not exceeding 2 meters. After micro-differential blasting, the ore is transported to the pass by a loader. This step reduces the overall ground pressure risk through sequential mining and avoids plastic deformation of the footwall pillars due to long-term pressure by prioritizing the mining of stress concentration areas, thereby ensuring the safety of subsequent hanging wall pillar mining.

[0030] It is important to note that "upper" and "lower" here do not refer to a positional relationship, but rather to a description of the sequence of mining operations. Therefore, the positional relationship between the hanging wall pillar and the footwall pillar is not fixed, and two pillars with different configurations will have different effects. For example, if the top surface of the footwall pillar is attached to the bottom surface of the hanging wall pillar, the footwall pillar is usually located near the transport roadway, bears less tectonic stress, and is more directly affected by mining activities below. Prioritizing the mining of the footwall pillar can prevent it from undergoing long-term pressure leading to plastic deformation or instability, and reduce the risk of sudden ground pressure events. The hanging wall pillar is close to the surface or overlying strata, resulting in a high concentration of ground pressure. If the hanging wall is mined first, it may cause roof subsidence or even surface collapse. However, if the footwall is mined first and then backfilled, the resulting backfill can replace the pillar to support the hanging wall surrounding rock, significantly improving the safety of subsequent operations. At the same time, the footwall backfill creates a stable working platform for subsequent hanging wall mining, avoiding roadway deformation and ventilation obstruction caused by untreated goaf areas, and shortening the stope preparation cycle.

[0031] For example, the side boundary of the footwall pillar is attached to the side boundary of the hanging wall pillar. In this case, the spatial relationship between the footwall and hanging wall pillars is relative to the left or right. The footwall pillar is on the structurally weak side, and the hanging wall pillar is on the stable surrounding rock side. The hanging wall and footwall have separate loading routes to avoid cross-disturbance. During mining, the footwall pillar on the structurally weak side is mined first, thereby prioritizing the mining of high-stress pillars and reducing the disturbance to the rock mass during subsequent mining. After the footwall pillar is mined out, it is backfilled to form a support structure before the hanging wall pillar is mined. The backfill structure is used to constrain roof displacement and reduce disturbance to the rock mass.

[0032] S104. Mining the hanging wall pillars. Specifically, after the backfill in the footwall pillar area reaches its design strength, the hanging wall pillars are mined using the same shallow-hole ore extraction technology. During mining, a portion of the retaining wall pillars is retained to isolate the backfill. The ore extraction process after blasting is the same as that in the footwall. This step utilizes the rigid support formed by the backfill to replace the pillar function, controlling the movement of the surrounding rock in the hanging wall through the backfill, avoiding roof collapse and surface subsidence. At the same time, the phased mining reduces the exposed area of ​​the goaf, thereby optimizing the ground pressure distribution.

[0033] Subsequent backfilling is carried out throughout the entire pillar mining process. After each pillar is mined, it is backfilled with cemented tailings to prevent instability of the surrounding rock caused by prolonged exposure of the goaf. For example, the bottom 5m backfill layer has a cement-tailings ratio of 1:4, and the upper layer has a cement-tailings ratio of 1:6, with a slurry concentration of 63-65%, ensuring a 28-day strength ≥2.5 MPa. Backfilling is implemented in multiple layers, each 1.5-2 meters high. After the previous layer has set, a retaining wall is built to fill the upper layer until it reaches the roof.

[0034] Traditional open-stope methods (such as the conventional room-and-pillar method) are prone to roof instability, surface subsidence, and resource losses due to stress concentration in the pillars if the goaf is not treated in a timely manner. In this scheme, the footwall pillars are mined and backfilled first to form a support structure, and the hanging wall pillars are mined later, avoiding the exposure of the entire goaf and reducing the possibility of surrounding rock instability caused by pillar recovery in high goaf areas. The backfill replaces the pillars to bear the roof pressure, thereby reducing the amount of permanent pillars required and improving the recovery rate. The goaf is sealed in time after backfilling to inhibit surrounding rock movement and avoid surface subsidence. The pillars are divided according to their location and rock stress and mined sequentially to reduce the risk of stress superposition during simultaneous mining, thereby avoiding stope collapse due to uncontrolled ground pressure.

[0035] In some implementations, refer to Figure 2 In step S103, the pillar is divided into an upper pillar and a lower pillar. The lower pillar is mined and backfilled after ore extraction. This includes: S1031, the lower pillar is mined layer by layer from bottom to top, shallow-hole blasting removes some ore and leaves some ore as a working platform for continued upward mining. Specifically, in this step, the layered mining of the lower pillar from bottom to top refers to the mining sequence that advances layer by layer from the bottom to the top of the ore body. The layer height is determined based on the stability of the ore and the performance of the drilling equipment. This layered approach achieves phased control of ground pressure, thereby avoiding the risk of collapse caused by large-scale roof exposure. Shallow-hole blasting is a blasting technique that uses drilled holes and controlled blasting energy to break up rock. Holes are arranged horizontally or upwards in parallel, and ore is broken up using micro-delay blasting technology. This design can precisely control the ore body boundary, reduce damage to the hanging wall and footwall, and lower the ore dilution rate. Partial ore release refers to the partial release of the broken ore body after blasting, thereby retaining the remaining ore as a working platform for subsequent mining. This allows personnel to safely perform drilling, support, and other operations on the ore pile, while the temporarily retained ore provides temporary support to the surrounding rock, suppressing ground pressure manifestation and ensuring the stability of the working face, thus avoiding open-face exposure. Layered mining reduces the risk of collapse by limiting the area exposed at one time; refined parameters of shallow-hole blasting reduce the generation of large blocks and improve ore extraction efficiency; the dynamic support system formed by local ore extraction and ore retention not only ensures operational safety but also eliminates the need for additional manual platforms, significantly reducing support costs and time consumption. These three factors work together to solve the problems of roof instability and large ore block retention during the mining of steeply inclined ore bodies.

[0036] In some implementations, refer to Figure 3In S101, the preparation work includes: S1011, leaving a top pillar at the top of the pillar and excavating a connecting tunnel between the top pillar and the top of the ore body; In S103, dividing the pillar into the hanging pillar and the footing pillar, mining the footing pillar and backfilling after ore extraction includes: S1032, mining the footing pillar to half the pillar elevation, and personnel entering the mine through a short connecting tunnel in the top pillar connecting tunnel. Specifically, the top pillar refers to the ore body structural layer retained at the top of the pillar. Its core function is to support the pressure of the overlying strata through its own bearing capacity, preventing premature collapse of the roof in the goaf, thereby maintaining the overall stability of the stope. It is especially suitable for ore bodies with moderate rock stability or local fracture zones. The top pillar connecting roadway is a horizontal roadway excavated between the bottom of the top pillar and the top of the ore body. It serves as a permanent passage for personnel, equipment transportation, and ventilation, and optimizes the airflow distribution within the stope through its horizontal connectivity, reducing ventilation dead zones. When the layered mining height exceeds the safe range of conventional operations (i.e., half the pillar elevation), personnel enter the mine by excavating a short connecting roadway. The short connecting roadway is a vertical or inclined channel temporarily excavated from the bottom plate of the top pillar connecting roadway. By directly connecting to the working face of the high-layered stope, it allows workers to safely reach the work point without climbing from the bottom ore pile, reducing the risk of falls from height. Its excavation adopts shallow hole blasting combined with lightweight rock drilling equipment (such as the YT-28 drilling rig) to ensure construction flexibility and timeliness. As a permanent support structure, the roof pillars limit the exposed area of ​​the goaf roof within a safe threshold, suppressing the risk of surrounding rock deformation. The roof pillar connecting tunnels construct a stable three-dimensional channel network, providing a spatial reference for the excavation of short connecting tunnels. As dynamic access points, the short connecting tunnels avoid the hidden dangers of personnel climbing the ore piles, avoiding the high cost of setting up temporary platforms while ensuring the process requirements of flexible adjustment of layer height. Thus, they collaboratively solve the problem of safe access for high-altitude workers to and from the mining area in the layered mining of steeply inclined ore bodies.

[0037] In some implementations, refer to Figure 4In S103, the pillar is divided into the hanging wall pillar and the footwall pillar. The footwall pillar is mined and backfilling is carried out after the ore is extracted. This includes: S1033, mining the footwall ore body until the end, performing segmented concentrated ore extraction, and then backfilling the empty area. Specifically, segmented concentrated mining refers to the process where, after all the layered mining of the footwall pillars is completed, the ore is no longer retained as a working platform. Instead, a loader or vibratory ore feeder is used to transport the ore temporarily stored in the stope out in one go. The mining output can reach 70%-80% of the total mining output, thereby shortening the mining cycle, reducing the energy consumption of frequent equipment entry and exit from the stope, and leaving working space for filling the voids. Filling the voids involves immediately filling the footwall voids with cemented tailings after concentrated mining. For example, the slurry concentration of the filling material is controlled at 63-65%, with a high-strength mix of 1:4 lime-sand ratio at the bottom 5m height and a normal mix of 1:6 lime-sand ratio at the top. This high-strength filling material at the bottom suppresses the displacement of the footwall surrounding rock and forms uniform support through the upper filling material, creating stable boundary conditions for subsequent footwall pillar mining.

[0038] While the ore retained during the stratified mining stage provides temporary support, prolonged retention increases the risk of surrounding rock creep. Concentrated ore extraction in sections, by rapidly clearing the stope, shortens the roof exposure time and reduces the probability of ground pressure manifestation. Backfilling follows immediately, using high-strength backfill at the bottom to resist lateral pressure from the hanging wall, while the continuous support surface formed by the upper backfill controls the roof settlement, preventing the collapse of the goaf from interfering with the recovery of the hanging wall pillars. This scheme, while ensuring mining safety, improves ore extraction efficiency and reduces the disruption to the mining-backfilling process caused by backfilling delays.

[0039] In some implementations, refer to Figure 5 In S101, the preparatory work includes: S1012, excavating the hanging wall haulage roadway along the bottom of the hanging wall of the ore body; in S104, the mining of the hanging wall pillars includes: S1041, leaving a portion of the pillar unmined at the bottom of the hanging wall pillar near the hanging wall haulage roadway as a safety pillar. Specifically, the hanging wall haulage roadway is a horizontal transport channel excavated along the boundary of the hanging wall surrounding rock of the ore body. Its core function is to directly connect the hanging wall pillar stope with the main transport system, shorten the ore transfer distance and optimize the ventilation path, which is especially suitable for the independent mining stage of the hanging wall pillar in steeply dipping ore bodies; while the safety pillar refers to the unmined ore body retained at the bottom of the hanging wall pillar in the area adjacent to the hanging wall haulage roadway. Its high-strength rock mass structure resists the lateral pressure of the hanging wall surrounding rock, preventing roof collapse or wall convergence deformation of the haulage roadway due to mining stress concentration, thereby ensuring the long-term stability of the transport channel.

[0040] The hanging wall transport roadway shortens the ore transport path and reduces the energy consumption of trackless equipment by directly embedding it into the hanging wall boundary. The safety pillar, on the other hand, forms a rigid support body to suppress the displacement of the hanging wall surrounding rock within a safe threshold and blocks the transmission path of the goaf ground pressure to the hanging wall transport roadway. This avoids the production losses caused by roadway maintenance in traditional methods and ensures the continuity of parallel operations of hanging wall pillar mining and ore transportation, thereby further improving the overall efficiency of the mining area.

[0041] In some implementations, refer to Figure 6 In S101, the preparation of the mining project includes: S1013, using the existing ore extraction roadway at the bottom of the ore pillar, wherein the hanging wall transport roadway passes through the ore extraction roadway but is not parallel to the ore extraction roadway, and the hanging wall transport roadway is set at the end of the ore extraction roadway near the hanging wall ore pillar; In S104, the mining of the hanging wall ore pillar includes: S1042, expanding and scouring the ore extraction roadway on one side of the hanging wall ore pillar, and forming the hanging wall loading chamber. Specifically, utilizing the existing ore extraction roadway at the bottom of the pillar refers to directly using the ore transport channel already developed during the lower pillar mining stage, avoiding the need to repeatedly excavate new roadways, thereby reducing the amount of preparatory work and preserving the stress balance state of the original roadway's surrounding rock. Meanwhile, the upper transport roadway passes through the ore extraction roadway but is not parallel to it, requiring the upper transport roadway to cross the ore extraction roadway at an oblique angle or perpendicularly. This non-parallel intersection layout eliminates planar conflicts in the transport paths, avoids interference with equipment passage, and utilizes the natural support structure formed by the intersection to enhance the stability of the roadway roof. During the mining of the upper pillar, widening the ore extraction roadway on one side of the upper pillar involves widening the sidewall of the ore extraction roadway near the upper pillar through shallow-hole blasting, forming an upper loading chamber. The upper loading chamber is a rectangular loading space constructed at the end of the widened ore extraction roadway. By installing vibratory ore feeders or loader loading points, centralized loading and rapid transfer of ore are achieved.

[0042] In some implementations, refer to Figure 7 In S101, the preparatory work includes: S1014, excavating a hanging wall raise along the vertical direction of the ore body on the surface of the hanging wall pillar, connecting it to the bottom ore extraction roadway. Simultaneously, the hanging wall raise also connects to the upper-middle ventilation roadway. Specifically, the hanging wall raise is a shaft excavated along the vertical development direction of the hanging wall pillar. Its core function is to construct a vertical or inclined downward channel along the side surface of the hanging wall pillar, directly connecting the bottom ore extraction roadway and the upper-middle ventilation roadway, forming an independent ventilation and material transport path. Through this vertically connected design, fresh air can enter the raise from the bottom ore extraction roadway, ascend to the working face, and then carry contaminated air into the upper-middle ventilation roadway, finally being discharged to the surface by the return air system. This achieves a bottom-in, top-out ventilation cycle during the mining of steeply inclined ore bodies, reducing dust and blasting hazard gas emissions and improving the safety of the working environment.

[0043] In some implementations, refer to Figure 8In S101, the preparatory work includes: S1015, excavating a footwall raise along the vertical direction of the ore body on the surface of the footwall pillar. The footwall raise and the hanging wall raise are connected by a top connecting roadway, which is located at the top of the pillar ore body. Specifically, the footwall raise is a shaft excavated along the footwall pillar perpendicular to the ore body. Its core function is to work with the hanging wall raise to construct a dual-channel system that runs through the pillar. Through the top connecting roadway, a closed ventilation and transportation loop is formed, thereby achieving a ring-shaped ventilation path for footwall intake and hanging wall return during the mining of steeply inclined ore bodies: fresh air enters from the footwall raise, is horizontally guided to the hanging wall raise through the top connecting roadway, and is finally discharged by the return air system, thus avoiding ventilation dead zones in the stope, further reducing the retention time of polluted air, and improving the safety of the working environment.

[0044] During the mining process, this structure solves the problem of ventilation efficiency degradation in long-distance ore blocks through a spatially symmetrical layout: traditional single-well ventilation modes are prone to airflow short-circuiting due to increased wind resistance when the ore block length is too long. However, this solution, through the parallel design of the footwall and hanging wall wells, divides the ventilation path into independent intake and return air branches, reducing air pressure loss and utilizing the natural pressure difference formed by the dip angle of the ore body to enhance airflow stability. At the same time, the top connecting roadway, as a horizontal connecting channel, not only optimizes airflow distribution but also provides a shortcut for equipment transportation—drilling equipment can be lifted to the connecting roadway through the footwall well and then transported horizontally to the hanging wall stope, or enter the bottom ore extraction roadway through the hanging wall stope via the same path, avoiding the inefficient path of detouring through stage roadways in traditional methods, thereby shortening material handling time.

[0045] In some implementations, refer to Figure 9 In S101, the preparation work includes: S1016, using the existing ore extraction roadway at the bottom of the pillar; in S103, dividing the pillar into the hanging wall pillar and the footwall pillar, mining the footwall pillar, and backfilling after ore extraction, it includes: S1034, expanding and scouting the ore extraction roadway on one side of the footwall pillar to form the footwall loading chamber; in S104, mining the hanging wall pillar, it includes: S1042, expanding and scouting the ore extraction roadway on one side of the hanging wall pillar to form the hanging wall loading chamber.

[0046] Specifically, using the existing ore extraction roadway at the bottom of the pillar refers to directly utilizing the ore transportation channel that has been developed during the lower pillar mining stage, avoiding the need to repeatedly excavate new roadways, thereby reducing the amount of preparatory work and preserving the stress balance state of the original roadway surrounding rock.

[0047] When mining the footwall pillars, the ore extraction roadway on one side of the footwall pillar is widened by shallow-hole blasting to expand the sidewall of the roadway near the footwall pillar, thus forming a footwall loading chamber. The footwall loading chamber is a rectangular loading space constructed at the end of the widened ore extraction roadway. A vibratory ore feeder or a loader is installed at the loading point to achieve centralized loading and rapid transfer of ore from the footwall. Similarly, when mining the upper pillars, the ore extraction roadway on one side of the upper pillar is widened using the same technical principle to form an upper loading chamber, but it is necessary to ensure that the two chambers are staggered to avoid overlapping transport paths.

[0048] Reusing the ore extraction roadway reduces the scope of surrounding rock disturbance by minimizing the excavation of new roadways, thus maintaining the stress bearing continuity of the safety pillars. The symmetrical separation of the loading chambers in the footwall and hanging wall enables independent transfer of ore between the footwall and hanging wall pillars through a dual-channel transport mechanism. This avoids the problem of cross-interference of ore flows in traditional single-roadway transport, improves ore transfer efficiency, and collaboratively solves the problems of ore transfer path conflicts and low loading efficiency in dual-pillar mining.

[0049] In some implementations, refer to Figure 10 In S1034, after the ore extraction roadway on one side of the footwall pillar is expanded and a footwall loading chamber is formed, the pillar is divided into an upper footwall pillar and a lower footwall pillar. The lower footwall pillar is mined and backfilled after extraction. S1035 also includes temporary support reinforcement within the expanded space. Specifically, temporary support reinforcement refers to the immediate reinforcement of the roof and sidewalls of the chamber formed by the expanded space using anchor bolts combined with metal mesh or retractable supports. Its core function is to suppress the expansion of the loosening zone caused by the release of surrounding rock stress after the expanded space, avoid chamber spalling or roof collapse, and ensure the safety of ore loading operations.

[0050] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

[0051] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A two-step mining method for shallow-hole ore extraction with column support and subsequent backfilling, characterized in that, include: Arrange the preparation work; Arrange cutting work to create mining space; The pillar is divided into the hanging wall pillar and the footing wall pillar. The footing wall pillar is mined and backfilled after the ore is extracted. Mining hanging wall ore pillar; The aforementioned preparation and preparation work includes: leaving a top pillar at the top of the pillar, and excavating a connecting tunnel between the top pillar and the top of the ore body; in the process of dividing the pillar into the hanging wall pillar and the footwall pillar, mining the footwall pillar, and backfilling after ore extraction, the following includes: mining the footwall pillar to half the pillar elevation, and personnel entering the mine through a short connecting tunnel from the top pillar connecting tunnel; The process of dividing the ore pillar into the hanging wall pillar and the footwall pillar, mining the footwall pillar, and backfilling after ore extraction includes: mining the footwall ore body to the end, performing segmented and concentrated ore extraction, and then backfilling the empty area. The above-mentioned layout and preparation project includes: excavating a hanging wall transport roadway along the bottom of the hanging wall of the ore body; the above-mentioned mining of the hanging wall pillars includes: leaving a portion of the pillars at the bottom of the hanging wall pillars near the hanging wall transport roadway as a safety pillar. The aforementioned preparation and preparation work includes: utilizing the existing ore extraction roadway at the bottom of the ore pillar, wherein the hanging wall transport roadway passes through the ore extraction roadway but is not parallel to it, and the hanging wall transport roadway is located at one end of the ore extraction roadway near the hanging wall ore pillar; the mining of the hanging wall ore pillar includes: expanding and scouting the ore extraction roadway on one side of the hanging wall ore pillar to form a hanging wall loading chamber.

2. The two-step ore retention and subsequent backfilling mining method for shallow-hole ore extraction according to claim 1, characterized in that, The process of dividing the ore pillar into the hanging wall pillar and the footwall pillar, mining the footwall pillar, and backfilling after ore extraction includes: mining the footwall pillar in layers from bottom to top, shallow-hole blasting to extract ore and some of the ore, leaving some ore as a working platform for continued mining.

3. The two-step ore retention and subsequent backfilling mining method for shallow-hole ore extraction according to claim 1, characterized in that, The aforementioned preparation and preparation work includes: excavating a hanging wall riser on the surface of the hanging wall pillar in line with the vertical direction of the ore body, so that it is connected to the bottom ore extraction roadway. At the same time, the hanging wall riser is also connected to the upper and middle ventilation roadway.

4. The two-step ore retention and subsequent backfilling mining method for shallow-hole ore extraction according to claim 2, characterized in that, The aforementioned preparation and preparation work includes: excavating a footwall riser on the surface of the footwall pillar in line with the vertical direction of the ore body; the footwall riser and the hanging wall riser are connected by a top connecting roadway, wherein the top connecting roadway is located at the top of the pillar ore body.

5. The two-step ore retention and subsequent backfilling mining method for shallow-hole ore extraction according to claim 1, characterized in that, The aforementioned preparatory mining operation includes: utilizing the existing ore extraction roadway at the bottom of the pillar; dividing the pillar into an upper pillar and a lower pillar, mining the lower pillar, and backfilling after ore extraction, including: widening and scouting one side of the lower pillar's ore extraction roadway to form a lower loading chamber; and mining the upper pillar, including: widening and scouting one side of the upper pillar's ore extraction roadway to form an upper loading chamber.

6. The two-step ore retention and subsequent backfilling mining method for shallow-hole ore extraction according to claim 5, characterized in that, After the ore roadway is opened on one side of the expanded hanging pillar and a hanging loading chamber is formed, the process of dividing the pillar into the hanging pillar and the hanging pillar, mining the hanging pillar, and backfilling after ore extraction also includes: temporary support reinforcement in the space opened up by the expanded ore roadway.

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