A sublevel filling mining method for steeply inclined thick and large broken ore body

Abstract

This application provides a segmented backfilling mining method for steeply inclined, thick, and fractured ore bodies, comprising the following steps: arranging two-stage segmented deep-hole stopes perpendicular to the ore body strike; the first-stage stope has a span of 4m, and the second-stage stope has a span of 16m; the stope cutting works are arranged; 0.5m thick concrete is poured into the ore-exit roadways of each segment as an artificial false roof for stope recovery; and a 1.0-1.5m length is reserved at the end of the stope without concrete pouring; the ore-exit roadways of the first-stage stope are... In the mining area, upward parallel medium-deep holes are drilled for blasting. After blasting, ore is extracted, followed by goaf scanning and filling. In the segmented drilling ore extraction roadway of the two-step mining area, upward fan-shaped medium-deep holes are drilled for blasting. After blasting, ore is extracted, followed by goaf scanning and filling. An artificial false roof is constructed in the reserved space of the segmented drilling high access roadway to isolate the blasting damage of the lower mining area to the upper segmented drilling ore extraction roadway, thus ensuring safe operation and efficient, low-damage loading.

Description

Technical Field

[0001] This invention relates to the field of mining technology, specifically to a segmented backfilling mining method for steeply inclined, thick, and fractured ore bodies. Background Technology

[0002] Steeply inclined, thick, and fractured ore bodies are among the most technically challenging and safety-risk types of ore bodies in underground mining. Currently, the industry has formed a mining pattern with backfilling as the main method and open-pit and caving methods as supplements. It is gradually transforming from traditional small-structure, low-efficiency mining to large-structure, mechanized, and intelligent mining. However, ground pressure control, ore loss and depletion control, and efficient mining are still the core bottlenecks restricting its development.

[0003] From a practical mining perspective, the downward sublevel or access backfill method, using a high-strength backfill body as the roof, achieves pillarless continuous mining and is the most widely used mining method for this type of ore body. It is suitable for extremely fractured, high-grade ore bodies. Through top-down layered mining and cemented backfilling, it achieves a recovery rate of >90% and a dilution rate of <10%, effectively avoiding the risk of roof collapse. However, it has problems such as a large mining-to-cut ratio, cumbersome procedures, low efficiency, and high backfilling costs. The sublevel stope backfill method is suitable for moderately fractured ore bodies, balancing efficiency and cost, with a single stope production capacity of 500-1000 t / d. However, it has a large stope exposure area and is difficult to control ground pressure. Sublevel caving without pillars... This method is only applicable to low-grade, large-scale ore bodies where surface subsidence is permissible. Although it offers high production capacity and low cost, the dilution rate is as high as 30% to 50%, resulting in serious resource waste and limiting its application in high-value mines. Therefore, in general, the current mining challenges facing steeply dipping, thick, and fractured ore bodies can be summarized as follows: the fractured rock mass has poor self-stability, with prominent risks of spalling and roof collapse, requiring combined support such as grouting and anchor wire mesh, which results in high costs and construction difficulties; ore dilution control is difficult, as the collapse of the hanging wall and footwall can easily lead to dilution, and the ore release from the fractured ore body is prone to arching, resulting in losses; traditional mining methods mostly adopt small stopes and small access routes, with low levels of mechanization and continuity, limiting the improvement of production capacity. Summary of the Invention

[0004] In order to improve the mining efficiency of thick and fractured ore bodies and enhance the production capacity of the stope, this application provides a segmented backfilling mining method for steeply inclined thick and fractured ore bodies.

[0005] The purpose of this invention is to construct an artificial false roof in the reserved space of the segmented rock drilling high access roadway, which isolates the blasting damage of the lower mining area to the upper segmented rock drilling ore extraction roadway, and provides a guarantee for the safe operation and efficient and low-damage loading of high-value ore extraction equipment.

[0006] To achieve the above objectives, the technical solution adopted by this invention is as follows: A segmented backfilling mining method for steeply dipping, thick, and fractured ore bodies includes the following steps: Step 1: Layout a two-step segmented medium-deep hole stope perpendicular to the strike of the ore body; the first step stope has a span of 4m, and the second step stope has a span of 16m. Step 2: Arrange the mining and cutting works in the mining area, including the intermediate haulage roadway, the segmented haulage roadway, the mining area connecting roadway, the segmented rock drilling ore extraction roadway, the ore pass, the cutting cross roadway, and the cutting riser; Step 3: Pour 0.5m thick concrete into each segment of the rock drilling and ore extraction roadway to serve as an artificial false roof for the mining of the lower segment or lower middle segment. Leave a 1.0 to 1.5m length unpoured at the end of the mining area to connect the lower segment mining area with the upper segment rock drilling and ore extraction roadway and to serve as the mining area return air passage. Step 4: Construct upward parallel medium-deep holes within the segmented rock drilling roadways of the first-step mining area for blasting. After blasting, operate for 2-3 meters. 3 The diesel loader enters the empty area to load the collapsed ore body. After that, the empty area is scanned. After the scan is completed, the first-step stope is filled. Step 5: Construct upward fan-shaped medium-deep holes in the segmented rock drilling roadways of the second-step mining area for blasting. After blasting, manually operate for 2-3 meters. 3 Diesel-powered loaders extract ore directly below the segmented rock drilling and ore extraction roadway where concrete is poured in the upper part. The remaining ore body is then extracted using remote-controlled loaders. After the ore extraction is completed, the empty area is scanned. After the scan is completed, the second-stage stope is filled.

[0007] In the technical solution of this application, an artificial false roof is constructed in the reserved space of the segmented drilling high access roadway. This isolates the blasting damage of the lower mining area to the upper segmented drilling ore roadway and serves as a fixed anchor point to support the roof of the first and second stage mining areas. The first stage mining area is designed with an ultra-small span parameter of 4m. Without increasing a large amount of preparatory work, the first stage mining area adopts parallel hole mining, avoiding the "collapse" phenomenon caused by the use of upward fan-shaped hole mining. At the same time, it significantly reduces the mining and filling cycle of the first stage, reduces the exposure time of the broken original rock sidewalls, and reduces the investment cost of high-strength filling material in the first stage mining area.

[0008] As a further improvement of the present invention, in step two, the cross-sectional dimensions of the intermediate transport level roadway and the segmented transport level roadway are 4m×3.8m, the cross-sectional dimensions of the segmented rock drilling and ore extraction roadway are 4m×4.5m, and anchor mesh + shotcrete support or anchor mesh + prestressed anchor cable + shotcrete support are adopted. The cross-sectional dimensions of the cut transverse roadway are 4m×3.8m, and the diameter of the cut return air shaft and chute is 2m.

[0009] The segmented drilling ore extraction roadway is designed with a high-access method, the purpose of which is to reserve space for pre-support of the mining area.

[0010] As a further improvement of the present invention, the specific construction steps of the artificial false roof in step three are as follows: Before constructing the artificial false roof, the bottom plate of the access road mining area is leveled to make the bottom plate flat, and then a steel mesh is laid; when laying the steel mesh, the longitudinal bars are laid first and then the transverse bars are laid, with the longitudinal bars at the bottom and the transverse bars at the top. The intersections of the longitudinal and transverse bars are reinforced with wire or welded. Horizontal boreholes are drilled 15-20cm from the bottom plate on the sidewall of the roadway, and are connected to the sidewall of the adjacent segmented rock drilling roadway. The borehole diameter is 70mm, the length is 6m, and the spacing is 1.0-1.2m; after the horizontal borehole construction is completed, grouting pipes with a diameter of 42mm are used for grouting. Medium-pressure grouting is performed at a pressure of 2–3 MPa. Grouting is stopped when the grouting pressure reaches 1.1–1.2 times the design pressure or when grout overflows from adjacent holes. After grouting, two 4 mm diameter iron wires are wound around a 12 mm diameter, 6.4–6.6 m long threaded steel bar and passed through a horizontal borehole, forming hook-like structures at both ends. The hooks are connected to the steel mesh using a 12 mm diameter first lifting bar. Cement mortar is then injected into one or both sides of the horizontal borehole to fill it. Finally, a 0.5 m thick layer of concrete is poured in the roadway. After curing, blasting and ore extraction can be carried out in the lower mining area.

[0011] The artificial false roof of the stope adopts a design of steel mesh and concrete, combined with hydraulic grouting, wound iron wire and threaded steel bars and mortar, to construct a safe and reliable mechanical load-bearing structure, which greatly enhances the self-stabilizing ability and resistance to blasting disturbance of the stope roof, and also provides a guarantee for the safe operation and efficient and low-damage loading of high-value mining equipment.

[0012] As a further improvement of the present invention, the steel mesh includes main bars and secondary bars. The main bars are 12mm diameter threaded steel bars with a spacing of 500mm×500mm. Only 9 longitudinal main bars are laid along the width of the access road, and they are laid out to both sides with the center line of the concrete pouring space as the reference. The length is 1.0 to 1.5m shorter than the length of the mining area. The rest are secondary bars, which are 6mm diameter round steel bars with a spacing of 500mm×500mm. The first hanging bar is connected to the connection point of the main and secondary bars.

[0013] The design of the main and secondary reinforcement bars of the steel mesh not only meets the requirements of reinforced concrete pouring, but also ensures the stability of the connection point with the first lifting bar, while saving material costs.

[0014] As a further improvement of the present invention, the connection point between the first lifting bar and the horizontal threaded steel bar is hung on the anchor rod of the roadway side support by a second lifting bar with a diameter of 12mm.

[0015] The design of the second suspension rod increases the number of points that provide force to the entire artificial ceiling, further ensuring the stability of the artificial ceiling.

[0016] As a further improvement of the present invention, during the construction of the two-step pre-support roof in the mining area, blast holes are simultaneously constructed in the drilling roadway of the lower section of the mining area. The bottom of the upward parallel medium-deep holes is 0.5m away from the bottom plate boundary of the upper section of the drilling roadway, the blast hole diameter is 65mm, the row spacing is 1.3-1.6m, the hole spacing within the row is 1.2m, and the blast holes are loaded with explosives normally. The bottom of the upward fan-shaped medium-deep holes is 0.5m away from the bottom plate of the upper section of the drilling roadway or the boundary of the adjacent first-step filling body, the blast hole diameter is 65mm, the row spacing is 1.5m, and the hole bottom distance is 1.8-2.2m.

[0017] As a further improvement of the present invention, during the construction of upward parallel medium-deep holes, an upward parallel medium-deep hole with a diameter of 76mm is constructed between the side holes of two adjacent rows of blast holes, and no explosives are loaded into the blast holes.

[0018] The aforementioned improvements enable smooth blasting of the sidewalls in the mining area, thereby enhancing the flatness and stability of the sidewalls.

[0019] As a further improvement of the present invention, before mining each segment of the mining area, the cutting well blasting holes next to the cutting well are first blasted to form a cutting groove. Then, the cutting groove is used as a free surface and compensation space to blast backwards in sequence. The first row of the main row is blasted with 1 to 2 rows, and then blasted with 2 to 3 rows each time. The amount of explosive is controlled not to exceed 550 kg. At the same time, the main row adopts "V" type micro-delay blasting.

[0020] The above-mentioned blasting method can minimize blasting disturbance.

[0021] As a further improvement of the present invention, the stope is sealed before filling and a water filtration facility is installed on the sealed wall. The filling retaining wall can be made of brick or steel structure. During filling, the bottom 4m range of the middle section of the sub-stope is filled with high-strength cemented filling grout, and the filling body strength is 3-4MPa. The filling body of the remaining first-step void has a 28-day strength of not less than 1.5MPa and a second-step strength of not less than 0.5MPa.

[0022] The filling retaining wall is used to isolate the surrounding shafts and tunnels to prevent slurry loss and pollution, and water filtration facilities are installed on the sealed wall to drain accumulated water in a timely manner and reduce bottom pressure.

[0023] As a further improvement of the present invention, after each segment of the filling body has been cured for 7 days, 2 to 3 filling holes are drilled on the poured concrete. The filling holes and the reserved return air passage of the stope are used for secondary filling. After the secondary filling and curing, expansive cement is used for a third filling. The mass ratio of expansive cement: fly ash: tailings: water is 1:0.4:6:2.0. After the third filling and curing for 7 days, the mining operation of the upper segment begins.

[0024] In summary, this application includes the following beneficial technical effects: 1. An artificial false roof was constructed in the reserved space of the segmented rock drilling high access roadway to isolate the upper segmented rock drilling ore extraction roadway from the blasting damage caused by the ore falling from the lower mining area. It also served as a fixed anchor point to support the roof of the first and second mining areas. Combined with "hydraulic grouting + wound iron wire and threaded steel + mortar", a safe and reliable mechanical load-bearing structure was constructed, which greatly enhanced the self-stabilizing ability and blasting disturbance resistance of the mining area roof. It also provided a guarantee for the safe operation and efficient and low-damage loading of high-value ore extraction equipment.

[0025] 2. The ultra-small span one-step stope design greatly reduces the exposure time of the original rock sidewalls in the stope. Combined with parallel drilling, the addition of auxiliary holes and "V"-shaped micro-differential blasting, it significantly reduces the cost of blasting vibration, ore dilution and high-strength backfill in the two-step stope, and realizes large-scale safe and efficient mining of steeply inclined thick and broken ore bodies. Attached Figure Description

[0026] 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.

[0027] Figure 1 This is an image of the first-level mining area using the existing downward approach method.

[0028] Figure 2 This is a cross-sectional view of a segmented filling mining method for a steeply inclined, thick, and fractured ore body, as described in this application.

[0029] Figure 3 for Figure 1 Sectional view of section I-I.

[0030] Figure 4 for Figure 3 Sectional view of section III-III.

[0031] Figure 5 for Figure 3 Sectional view of section IV-IV Figure 6 This is a schematic diagram of an artificial false ceiling.

[0032] Figure 7 This is a schematic diagram of a steel mesh.

[0033] Figure 8 A schematic diagram of wrapping wire around a rebar.

[0034] Explanation of reference numerals in the attached diagram: 1. Intermediate haulage roadway; 2. Mine pass; 3. Subgrade haulage roadway; 4. Mine pass connecting roadway; 5. Collapsed ore; 6. Backfill; 7. Subgrade drilling ore extraction roadway; 8. Stope connecting roadway; 9. Backfill retaining wall; 10. Stope return air passage; 11. Upward fan-shaped medium-deep hole; 12. Upward parallel medium-deep hole; 13. Threaded steel bar; 14. Anchor bolt; 15. Concrete layer; 16. Main reinforcement; 17. Secondary reinforcement; 18. Lifting bar connection point; 19. Binding wire; 20. First lifting bar; 21. 4mm wire; 22. Wire binding point; 23. Second lifting bar. Detailed Implementation

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0041] For ease of explanation, the following embodiments use a segmented backfilling mining method for a steeply inclined, thick, and fractured ore body as an example.

[0042] Please refer to Figures 2-8 This application discloses a segmented backfilling mining method for steeply inclined, thick, and fractured ore bodies, comprising the following steps: Step 1: Layout a two-step segmented medium-deep hole stope perpendicular to the strike of the ore body; the first step stope has a span of 4m, and the second step stope has a span of 16m. Step 2: Arrange the mining and cutting works in the mining area, including the intermediate transport level 1, the segmented transport level 3, the mining area connecting roadway 8, the segmented rock drilling and ore extraction roadway 7, the ore pass 2, the cutting cross roadway, and the cutting riser. Step 3: Pour a 0.5m thick concrete layer 15 into each segment of the rock drilling and ore extraction roadway 7 as an artificial false roof for the mining of the lower segment or lower middle segment. Leave a 1.0 to 1.5m length unpoured at the end of the mining area to connect the lower segment mining area with the upper segment rock drilling and ore extraction roadway and serve as the mining area return air passage 10. Step 4: Construct upward parallel medium-deep holes 12 within the segmented rock drilling roadway 7 of the first-step mining area, and carry out blasting. After blasting, operate for 2-3 meters. 3 The diesel loader enters the empty area to load the collapsed ore body. After that, the empty area is scanned. After the scan is completed, the first-step stope is filled. Step 5: Construct upward fan-shaped medium-deep holes 11 within the segmented rock drilling ore extraction roadway 7 in the second-step mining area for blasting. After blasting, manually operate for 2-3 meters. 3 The diesel-powered loader extracts ore directly below the segmented rock drilling roadway 7, where the upper concrete layer 15 is poured. The remaining ore body is then extracted using a remote-controlled loader. After the extraction is completed, the empty area is scanned, and the second-stage stope is then filled.

[0043] In the above implementation, an artificial false roof is constructed in the reserved space of the segmented drilling high access roadway to isolate the blasting damage of the lower mining area to the upper segmented drilling ore extraction roadway 7, and to serve as a fixed anchor point to support the roof of the first and second step mining areas. The first step mining area is designed with an ultra-small span parameter of 4m. Without increasing a large amount of preparatory work, the first step mining area adopts parallel hole mining, which avoids the "collapse" phenomenon caused by the use of upward fan-shaped hole mining. At the same time, it significantly reduces the mining and filling cycle of the first step, reduces the exposure time of the broken original rock sidewalls, and reduces the investment cost of high-strength filling material in the first step mining area.

[0044] Furthermore, in some implementation examples, in step two, the cross-sectional dimensions of the intermediate transport level 1 and the segmented transport level 3 are 4m×3.8m, the cross-sectional dimensions of the segmented rock drilling and ore extraction roadway 7 are 4m×4.5m, and the "anchor mesh + shotcrete support" or "anchor mesh + prestressed anchor cable + shotcrete support" is adopted. The cross-sectional dimensions of the cut transverse roadway are 4m×3.8m, and the diameter of the cut return air shaft and chute is 2m.

[0045] In the technical solution of this application embodiment, the segmented rock drilling ore extraction roadway 7 is designed with a high access method, the purpose of which is to reserve space for pre-support of the mining area.

[0046] Furthermore, in some implementation examples, the specific construction steps for the artificial false roof in step three are as follows: Before constructing the artificial false roof, the bottom plate of the access mining area is leveled to ensure it is flat, and then a steel mesh is laid. When laying the steel mesh, the longitudinal bars are laid first, followed by the transverse bars, with the longitudinal bars at the bottom and the transverse bars at the top. The intersections of the longitudinal and transverse bars are reinforced with 24# iron wire or welded. Horizontal boreholes are drilled 15-20cm from the bottom plate on the sidewall of the 7th section of the segmented rock drilling roadway, and connected to the sidewall of the adjacent 7th section of the segmented rock drilling roadway. The borehole diameter is 70mm, the length is 6m, and the spacing is 1.0-1.2m. After the horizontal boreholes are completed, 42mm diameter grouting pipes are used for medium-pressure grouting. Grouting is performed at a pressure of 2–3 MPa. Grouting is stopped when the grouting pressure reaches 1.1–1.2 times the design pressure (stabilized for 25 minutes) or when grout overflows from adjacent holes. After grouting, two 4 mm diameter iron wires 21 are wound around a 12 mm diameter, 6.4–6.6 m long threaded steel bar 13. The wires are then passed through the horizontal borehole, forming hook-like structures at both ends. The first lifting bar 20 with a diameter of 12 mm is used to connect the wires to the steel mesh connection point. Cement mortar is injected into one or both sides of the horizontal borehole to fill it. Finally, a 0.5 m thick concrete layer 15 is poured in the roadway. After curing, blasting and ore extraction can be carried out in the lower mining area.

[0047] In the technical solution of this application embodiment, the artificial false roof of the stope adopts a design of steel mesh and concrete, and is further combined with "hydraulic grouting + wound iron wire and threaded steel + mortar" to construct a safe and reliable mechanical load-bearing structure, which greatly enhances the self-stabilizing ability and blasting disturbance resistance of the stope roof, and also provides a guarantee for the safe operation and efficient and low-damage loading of high-value mining equipment.

[0048] In some implementation examples, the reinforcing mesh includes main bars 16 and secondary bars 17. The main bars 16 are 12mm diameter threaded steel bars of HRB335 grade, with a spacing of 500mm×500mm. Only 9 longitudinal main bars are laid along the width of the access road, and they are laid out to both sides based on the center line of the concrete pouring space. The length is 1.0 to 1.5m shorter than the length of the mining area. The rest are secondary bars 17, which are 6mm diameter round steel bars with a spacing of 500mm×500mm and a steel grade of HPB335 grade. The first hanging bar 20 is connected to the connection point of the main and secondary bars.

[0049] In the technical solution of this application embodiment, the design of the main and secondary bars of the steel mesh not only meets the requirements of reinforced concrete pouring, but also ensures the stability of the connection point with the first lifting bar 20, while saving material costs.

[0050] Furthermore, in some implementation examples, the connection point between the first lifting rod 20 and the horizontal threaded steel bar is suspended from the anchor rod 14 of the roadway side support by a second lifting rod 23 with a diameter of 12mm.

[0051] In the technical solution of this application embodiment, the design of the second suspension rod can increase the number of points that provide force to the entire artificial false ceiling, thereby further ensuring the stability of the artificial false ceiling.

[0052] Furthermore, in some implementation examples, during the construction of the pre-support roof in the two-step mining area, blast holes are simultaneously constructed in the segmented drilling and ore extraction roadway 7 of the lower segmented mining area. The bottom of the upward parallel medium-deep hole 12 is 0.5m away from the bottom plate boundary of the upper segmented drilling and ore extraction roadway 7, the hole diameter is 65mm, the row spacing is 1.3-1.6m, the hole spacing within the row is 1.2m, and the blast holes are loaded with explosives normally. The bottom of the upward fan-shaped medium-deep hole 11 is 0.5m away from the bottom plate of the upper segmented drilling and ore extraction roadway 7 or the boundary of the adjacent first-step filling body 6, the hole diameter is 65mm, the row spacing is 1.5m, and the hole bottom distance is 1.8-2.2m.

[0053] Furthermore, in some implementation examples, during the construction of the upward parallel medium-deep hole 12, an upward parallel medium-deep hole with a diameter of 76mm is constructed between the side holes of two adjacent rows of blast holes, and the blast holes are not loaded with explosives.

[0054] In the technical solution of this application embodiment, smooth blasting of the stope sidewall can be achieved, thereby improving the flatness and stability of the stope sidewall.

[0055] Furthermore, in some implementation examples, before the mining of each segment, the cutting well next to the cutting well is blasted to form a cutting groove. Then, the cutting groove is used as a free surface and compensation space for sequential blasting. The first row of the main row is blasted with 1 to 2 rows, and then 2 to 3 rows are blasted each time. The amount of explosive is controlled to not exceed 550 kg. At the same time, the main row adopts "V" type micro-delay blasting, which can minimize blasting disturbance.

[0056] Furthermore, in some implementation examples, the stope is sealed before backfilling, and water filtration facilities are installed on the sealed wall. The backfilling retaining wall 9 can be made of brick or steel structure. During backfilling, the bottom 4m range of the middle and bottom sub-section stope is filled with high-strength cemented backfilling grout, and the strength of the backfill body is 3-4MPa. The strength of the backfill body in the remaining first-step void area is not less than 1.5MPa after 28 days, and not less than 0.5MPa in the second step.

[0057] In the technical solution of this application embodiment, the filling retaining wall 9 is used to isolate the surrounding shafts and tunnels to prevent slurry loss and pollution, and a water filtration facility is installed on the sealed wall to drain accumulated water in time and reduce bottom pressure.

[0058] Furthermore, in some implementation examples, after each segment of the backfill body has been cured for 7 days, 2 to 3 backfill holes are drilled on the poured concrete. Secondary backfilling is carried out using the backfill holes and the reserved return air passage 10 in the stope. After the secondary backfilling and curing, a third backfilling is carried out using expansive cement. The mass ratio of expansive cement: fly ash: tailings: water is 1:0.4:6:2.0. After the third backfilling and curing for 7 days, the mining operation of the upper segment begins.

[0059] Specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific technologies or conditions are not specified in the embodiments, they shall be performed in accordance with the technologies or conditions described in the literature in this field or in accordance with the product manual.

[0060] This embodiment provides a detailed explanation of a segmented backfilling mining method for steeply inclined, thick, and fractured ore bodies: For a certain copper mine, the ore body has a dip angle of 35°–45°, a thickness of 30–40 m, and a maximum self-standing height of 15 m in the deep fractured rock mass, constituting a steeply dipping, thick, and fractured ore body; the method includes: 1) A two-stage segmented medium-deep hole stope is arranged vertically to the ore body. The first-stage stope is designed with an ultra-small span parameter of 4m. Without increasing the amount of preparatory work, the first-stage stope adopts parallel hole mining, avoiding the "collapse" phenomenon caused by upward fan-shaped hole mining. At the same time, it significantly reduces the mining and filling cycle of the first-stage stope, reduces the exposure time of the fractured original rock sidewalls, and reduces the investment cost of high-strength filling material in the first-stage stope. The second-stage stope has a span of 16m, and the segment height does not exceed the maximum self-standing height of the deep fractured rock mass, which is taken as 13m.

[0061] 2) Before mining, the mining and cutting engineering layout is carried out, including the middle section and sub-section transport roadway 3, sub-section drilling ore extraction roadway 7, ore pass 2, cutting cross roadway and cutting riser. The cross-section size of the middle section and sub-section transport roadway 3 is 4m×3.8m, the cross-section size of the sub-section drilling ore extraction roadway 7 is 4m×4.5m, and the "anchor mesh + shotcrete support" or "anchor mesh + prestressed anchor cable + shotcrete support" is adopted. The cross-section size of the cutting cross roadway is 4m×3.8m, and the diameter of the cutting return air riser and ore pass is 2m. The sub-section drilling ore extraction roadway adopts the high-access method, which is intended to reserve space for the pre-support of the mining roof.

[0062] 3) Each section of the rock drilling and ore extraction roadway 7 needs to be reinforced with a 0.5m thick concrete layer 15 as an artificial false roof for the lower section or lower-middle section stope. A 1.0-1.5m length should be left unreinforced at the end of the stope to ensure connection between the lower section stope and the upper rock drilling and ore extraction roadway, serving as the stope return air passage 10. Specifically, before constructing the artificial false roof, the bottom slab of the access stope needs to be leveled to ensure it is as flat as possible, and then the reinforcing mesh should be laid. When laying the reinforcing mesh, the longitudinal bars should be laid first, followed by the transverse bars, with the longitudinal bars at the bottom and the transverse bars at the top. At the intersections of longitudinal and transverse reinforcement bars, 24# iron wire is used for hooping or welding. The main reinforcement bar 16 is made of 12mm diameter threaded steel, grade HRB335, with a spacing of 500mm x 500mm. Nine longitudinal main reinforcement bars 16 are laid only along the width of the access road, extending outwards from the centerline of the concrete pouring space, with a length 1.0–1.5m shorter than the length of the stope. The secondary reinforcement bar 17 is made of 6mm diameter round steel, spaced at 500mm x 500mm, grade HPB335. 15–20cm of reinforcement bars are placed near the bottom slab on the sidewalls of the roadway. Drill a horizontal borehole at position m, connecting it to the sidewall of the adjacent segmented rock drilling roadway. The borehole diameter is 70mm, length is 6m, and spacing is 1.0-1.2m. After the horizontal borehole is completed, use a 42mm diameter grouting pipe for medium-pressure grouting at a pressure of 2-3MPa. Grouting is stopped when the grouting pressure reaches 1.1-1.2 times the design pressure (stabilized for 25 minutes) or when grout overflows from adjacent holes. After grouting, wrap two 4mm diameter iron rods around a 12mm diameter, 6.4-6.6m long threaded steel bar 13. Wire 21 passes through the horizontal borehole, forming a hook-like structure at both ends. It is connected to the main and secondary reinforcement connection point (reinforcement connection point 18) of the roadway using a first lifting bar 20 with a diameter of 12mm. The connection point between the first lifting bar 20 and the horizontal threaded steel (threaded steel 13) is also hung on the anchor rod 14 of the roadway side support using a second lifting bar 23 with a diameter of 12mm. Cement mortar is injected into one or both sides of the horizontal borehole to fill it. Finally, a 0.5m thick concrete layer is poured in the roadway. After curing, the blasting and ore extraction in the lower mining area can be carried out.

[0063] 4) During the construction of the pre-support roof in the two-step stope, blast holes can be simultaneously constructed in the segmented drilling and ore extraction roadway 7 of the lower segmented stope. Specifically, upward parallel medium-deep holes 12 can be constructed in the segmented drilling and ore extraction roadway 7 of the one-step ultra-small span stope. The bottom of the hole is 0.5m away from the bottom boundary of the upper segmented drilling and ore extraction roadway 7, the diameter of the blast hole is 65mm, the row spacing is 1.3-1.6m, the hole spacing within the row is 1.2m, and the blast holes are loaded normally. At the same time, blast holes in adjacent rows of blast holes can be constructed simultaneously. Between the side holes, construct an upward parallel medium-deep hole with a diameter of 76mm on each side. The blast holes are not loaded with explosives. The main purpose is to achieve smooth blasting of the sidewalls of the stope and improve the flatness and stability of the sidewalls of the stope. In the segmented rock drilling roadway of the second-stage stope, construct 11 upward fan-shaped medium-deep holes. The bottom of the hole is 0.5m away from the bottom plate of the upper rock drilling roadway or the boundary of the adjacent first-stage filling body. The diameter of the blast hole is 65mm, the row spacing is 1.5m, and the bottom distance of the hole is 1.8-2.2m.

[0064] 5) Before mining each section of the stope, first blast the cutting well next to the cut well to form a cutting groove. Then, using the cutting groove as a free surface and compensation space, blast sequentially backward. The first row of the main row is blasted with 1-2 rows, and then blasted with 2-3 rows each time. Control the amount of explosives. At the same time, the main row adopts "V" type micro-delay blasting to minimize blasting disturbance.

[0065] 6) After the ore is extracted, a loader is used to remove the ore in each section of the rock-drilling ore extraction roadway. In the first-stage stope, the loader can operate for 2-3 meters. 3 Diesel-powered loaders entered the empty area, achieving nearly 100% loading of the collapsed ore body; in the two-stage mining area, manual operation could be carried out first for 2-3 meters. 3 Diesel-powered loaders are used to extract ore directly beneath the upper cast-in-place roadway. The remaining ore body is then removed using remote-controlled loaders. This ensures maximum extraction of caved ore and maximizes the safety of personnel and equipment, minimizing ore loss and improving ore extraction efficiency. After all mining is completed, goaf scanning should be arranged as soon as possible, and the roof pre-support parameters and blasting parameters should be optimized and adjusted based on the goaf scanning results and ore extraction.

[0066] 7) Filling operations can begin once the empty area scanning is complete. Before backfilling, the stope must be sealed to isolate surrounding shafts and prevent slurry loss and contamination. Filtering facilities should be installed on the sealed walls to promptly drain accumulated water and reduce bottom pressure. The backfilling retaining wall can be constructed of brick or steel. During backfilling, a high-strength cemented backfilling slurry should be used for the bottom 4m range of the middle and lower sections of the stope, with a backfill strength of 3-4 MPa. The backfill strength of the remaining first-step empty areas should be no less than 1.5 MPa after 28 days, and no less than 0.5 MPa for the second-step areas. At the initial stage of operation, the single material level rise height must be strictly controlled to ensure the stability of the retaining wall. After 7 days of curing for each section of the backfill, 2-3 backfilling holes can be drilled in the poured concrete. Secondary backfilling can be carried out using the backfilling holes and reserved return air channels. After the secondary backfilling and curing, a third backfilling can be carried out using expansive cement. The mass ratio of expansive cement: fly ash: tailings: water is 1:0.4:6:2.0. After 7 days of curing for the third backfill, the upper section's mining operations can begin.

[0067] The method described in this application is used for segmented backfilling mining of steeply dipping, thick, and fractured ore bodies, achieving a recovery rate of 94-95% and a dilution rate of 7-8%.

[0068] It should be noted that the above-described embodiments are merely examples. Any embodiments with the same essential structure and function as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications conceivable to the embodiments by those skilled in the art, and other methods of constructing embodiments by combining some of the constituent elements, are also included in the scope of this application without departing from the spirit of this application.

Claims

1. A segmented backfilling mining method for steeply dipping, thick, and fractured ore bodies, characterized in that, Includes the following steps: Step 1: Layout a two-step segmented medium-deep hole stope perpendicular to the strike of the ore body; the first step stope has a span of 4m, and the second step stope has a span of 16m. Step 2: Arrange the mining and cutting works in the mining area, including the intermediate haulage roadway, the segmented haulage roadway, the mining area connecting roadway, the segmented rock drilling ore extraction roadway, the ore pass, the cutting cross roadway, and the cutting riser; Step 3: Pour 0.5m thick concrete into each segment of the rock drilling and ore extraction roadway to serve as an artificial false roof for the mining of the lower segment or lower middle segment. Leave a 1.0 to 1.5m length unpoured at the end of the mining area to connect the lower segment mining area with the upper segment rock drilling and ore extraction roadway and to serve as the mining area return air passage. Step 4: Construct upward parallel medium-deep holes in the segmented rock drilling and ore extraction roadway of the first-step stope, and carry out blasting. After the blasting is completed, operate a diesel loader to enter the empty area to load the collapsed ore body. Then scan the empty area. After the scan is completed, fill the first-step stope. Step 5: Construct upward fan-shaped medium-deep holes in the segmented rock drilling and ore extraction roadway of the second-step mining area for blasting. After blasting, first manually operate a diesel loader to extract ore directly below the segmented rock drilling and ore extraction roadway where concrete has been poured above. The remaining ore body is then extracted using a remote-controlled loader. After ore extraction, scan the empty area. After scanning, fill the second-step mining area.

2. The segmented backfilling mining method for steeply inclined, thick, and fractured ore bodies according to claim 1, characterized in that, In step two, the cross-sectional dimensions of the intermediate transport level roadway and the segmented transport level roadway are 4m×3.8m, the cross-sectional dimensions of the segmented rock drilling and ore extraction roadway are 4m×4.5m, and the support is provided by anchor mesh + shotcrete or anchor mesh + prestressed anchor cable + shotcrete. The cross-sectional dimensions of the cut transverse roadway are 4m×3.8m, and the diameter of the cut return air shaft and chute is 2m.

3. The segmented backfilling mining method for steeply inclined, thick, and fractured ore bodies according to claim 2, characterized in that, In step three, the specific construction steps for the artificial false roof are as follows: Before constructing the artificial false roof, the bottom slab of the access road mining area is leveled to ensure it is flat, and then a steel mesh is laid. When laying the steel mesh, the longitudinal bars are laid first, followed by the transverse bars, with the longitudinal bars at the bottom and the transverse bars at the top. The intersections of the longitudinal and transverse bars are reinforced with wire or welded. Horizontal boreholes are drilled 15-20cm from the bottom slab on the sidewall of the roadway, connecting with the sidewall of the adjacent segmented rock drilling roadway. The borehole diameter is 70mm, the length is 6m, and the spacing is 1.0-1.2m. After the horizontal boreholes are completed, medium-pressure grouting is performed using 42mm diameter grouting pipes. The grouting pressure is 2-3 MPa. Grouting is stopped when the grouting pressure reaches 1.1-1.2 times the design pressure or when the grout overflows from adjacent holes. After grouting, two 4 mm diameter iron wires are wrapped around a 12 mm diameter, 6.4-6.6 m long threaded steel bar and passed through the horizontal borehole, forming a hook-like structure at both ends. The hook is connected to the steel mesh connection point using a 12 mm diameter first lifting bar. Cement mortar is injected into one or both sides of the horizontal borehole to fill it. Finally, a 0.5 m thick layer of concrete is poured in the roadway. After curing, blasting and ore extraction can be carried out in the lower mining area.

4. The segmented backfilling mining method for steeply inclined, thick, and fractured ore bodies according to claim 3, characterized in that, The reinforcing mesh includes main bars and secondary bars. The main bars are 12mm diameter threaded steel bars with a spacing of 500mm×500mm. Only 9 longitudinal main bars are laid along the width of the access road, and they are laid out to both sides with the center line of the concrete pouring space as the reference. The length is 1.0 to 1.5m shorter than the length of the mining area. The rest are secondary bars, which are 6mm diameter round steel bars with a spacing of 500mm×500mm. The first hanging bar is connected to the connection point of the main and secondary bars.

5. The segmented backfilling mining method for steeply inclined, thick, and fractured ore bodies according to claim 3, characterized in that, The connection point between the first anchor bar and the horizontal threaded steel bar is attached to the anchor bolt of the roadway side support using a second anchor bar with a diameter of 12mm.

6. The segmented backfilling mining method for steeply inclined, thick, and fractured ore bodies according to claim 1, characterized in that, During the construction of the two-step mining pre-support roof, blast holes are simultaneously constructed in the drilling roadway of the lower section of the mining area. The bottom of the upward parallel medium-deep holes is 0.5m away from the bottom of the upper section of the drilling roadway floor, the blast hole diameter is 65mm, the row spacing is 1.3-1.6m, the hole spacing within the row is 1.2m, and the blast holes are loaded with explosives normally. The bottom of the upward fan-shaped medium-deep holes is 0.5m away from the bottom of the upper section of the drilling roadway floor or the boundary of the adjacent first-step filling body, the blast hole diameter is 65mm, the row spacing is 1.5m, and the hole bottom distance is 1.8-2.2m.

7. The segmented backfilling mining method for steeply inclined, thick, and fractured ore bodies according to claim 6, characterized in that, During the construction of upward parallel medium-deep holes, an upward parallel medium-deep hole with a diameter of 76mm is constructed between the side holes of two adjacent rows of blast holes. No explosives are loaded into the blast holes.

8. The segmented backfilling mining method for steeply inclined, thick, and fractured ore bodies according to claim 6, characterized in that, Before mining each section of the stope, the cutting well next to the cutting well is blasted to form a cutting groove. Then, the cutting groove is used as a free surface and compensation space to blast backwards in sequence. The first row of the main row is blasted with 1 to 2 rows, and then blasted with 2 to 3 rows each time. At the same time, V-shaped micro-differential blasting is used for the main row.

9. The segmented backfilling mining method for steeply inclined, thick, and fractured ore bodies according to claim 1, characterized in that, Before backfilling, the stope should be sealed and a water filtration system should be installed on the sealed wall. The backfilling retaining wall can be made of brick or steel. During backfilling, the bottom 4m range of the middle and bottom sub-stopes should be filled with high-strength cemented backfilling grout, and the strength of the backfill should be 3-4 MPa. The strength of the backfill in the remaining first-step voids should not be less than 1.5 MPa after 28 days, and not less than 0.5 MPa after the second step.

10. The segmented backfilling mining method for steeply inclined, thick, and fractured ore bodies according to claim 9, characterized in that, After each section of the backfill body has been cured for 7 days, 2-3 backfill holes are drilled in the poured concrete. Secondary backfilling is carried out using the backfill holes and the reserved return air passage in the stope. After the secondary backfilling and curing, a third backfilling is carried out using expansive cement. The mass ratio of expansive cement: fly ash: tailings: water is 1:0.4:6:2.

0. After the third backfilling and curing for 7 days, the mining operation of the upper section begins.

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