A false-inclined multi-layer strip mining method for gently inclined medium-thick underground sedimentary bauxite deposits

Abstract

The application discloses a kind of gently inclined medium-thick underground sedimentary bauxite pseudo-inclined multilayer strip mining method, and is especially suitable for gently inclined medium-thick bauxite safe and efficient mining with unstable roof.In the ore body, the ore body is divided into different sections by arranging in-vein middle section transport lane, and top and bottom columns are reserved between sections, and mining area is divided along the strike direction in section, and inter-column is left between mining areas, and mining area slope, lower sublevel ore loading flat roadway, sectional transport flat roadway, sublevel communication way and upper sublevel cutting flat roadway are excavated, and two specifications of strip are arranged, and mining area, ore block, mining area slope, strip and inter-column are pseudo-inclined arranged, and stoping operation is divided into two steps, and 3m~5m strip is mined first, and 6m~8m strip is mined later, and mining sequence is lower layer first and upper layer later, and each sublevel is filled in time after mining.The application is all in-vein engineering, and has the advantages of small mining and cutting engineering quantity, good safety and economy, and high stoping efficiency.

Description

Technical Field

[0001] This invention relates to a pseudo-inclined multi-layer strip mining method for gently inclined medium-thick underground sedimentary bauxite, which is particularly suitable for the safe and efficient mining of gently inclined medium-thick bauxite with unstable roof, and belongs to the field of underground metal mining technology. Background Technology

[0002] Currently, mining gently dipping underground bauxite deposits, especially thin to medium-thick ore bodies with dip angles of 9° to 25°, has always been a challenge for the industry. On the one hand, it poses a significant challenge to the slope-climbing ability of mechanized equipment; on the other hand, traditional room-and-pillar mining often leaves permanent pillars and inter-pillars, resulting in significant losses of ore resources. Layered filling mining or caving mining usually involves external development, with the intermediate transport roadway located in the footwall of the ore body. The transport connecting roadway from the stope to the intermediate transport roadway is relatively long, resulting in a large amount of mining and cutting work, and the mining and cutting process produces waste rock, which is not economically viable.

[0003] Based on the above problems, in recent years, experts and scholars in the industry have proposed methods such as inclined or pseudo-inclined strip backfilling mining and Z-type opposing mining. The main roadways are arranged within the vein, significantly reducing the amount of mining and cutting work. However, the strips in these mining methods are arranged along the strike, leaving large triangular ore bodies that are difficult to mine in one go. Drilling and blasting methods are required for subsequent mining, and controlling the ore body boundaries and blasting accuracy in these triangular ore bodies is difficult, resulting in significant dilution and losses. Furthermore, underground sedimentary bauxite deposits typically use manufactured sand backfilling, which has a high slurry concentration. During strip backfilling, if the pipeline is installed at the strip opening, the slurry cannot flow freely, leading to poor backfilling. If the pipeline is installed in the strip and backfilling is used, the pipeline wear is high, the backfilling process is complex, and it is difficult to guarantee the backfilling effect. At the same time, the above mining methods mainly target thin ore bodies. For medium-thick ore bodies with unstable roofs, a single mining operation can create large voids, posing safety risks. Summary of the Invention

[0004] Based on this, the purpose of this application is to provide a pseudo-inclined multi-layer strip mining method for gently dipping medium-thick underground sedimentary bauxite. This mining method is suitable for gently dipping medium-thick bauxite with a dip angle of 9° to 25°. The mining area slope, mining strips, and pillars are all pseudo-inclined to achieve mechanized operation. Layered mining and backfilling are adopted. The lower layer is mined first, and the upper layer is mined after backfilling to ensure the stability of the mining area. It has the advantages of small mining and cutting workload, high ore recovery rate, good backfilling effect and good safety.

[0005] A method for pseudo-dipping multi-layer strip mining of gently dipping, medium-thickness subsurface sedimentary bauxite includes the following steps:

[0006] S1. Stope Layout: The gently dipping, medium-thick bauxite ore is divided into different sections by the mid-section transport roadway near the footwall of the ore body. Roof pillars and floor pillars are reserved between the sections. Within each section, mining areas are divided along the strike of the ore body. Inter-pillars are reserved between mining areas, and ore blocks are divided within each mining area. Mining is organized using ore blocks as the basic unit. The inter-pillars, mining areas, and ore blocks are all arranged in a pseudo-dipping pattern, and the pseudo-dipping direction is consistent. The maximum angle between the pseudo-dipping and the horizontal plane is [value missing]. In the formula, α is the dip angle of the ore body, and β is the maximum allowable slope angle for the mining equipment;

[0007] S2. Mining preparation and cutting engineering: Excavate the mining area ramp from the middle section of the transport roadway. The mining area ramp is arranged in a pseudo-inclination, and the inclination direction is consistent with the mining area.

[0008] S3. Long-term mining project: Divide the mining area into mining strips, which are arranged in a pseudo-dipping direction consistent with the mining area, and serve as long-term mining faces.

[0009] S4, Mining area ventilation;

[0010] S5. Management of the mining area roof;

[0011] S6, Filling empty areas.

[0012] Furthermore, the mining method is used for gently dipping, medium-thickness underground sedimentary bauxite deposits with a dip angle of 9° to 25°.

[0013] Furthermore, in step S2, the mining area ramp serves as a connecting passage for personnel and equipment to enter and exit the mining area, and also as an air intake passage.

[0014] Furthermore, on the inclined slope of the mining area, 6m to 8m from the bottom plate of the ore block, a lower layer loading roadway is excavated along the strike of the ore body to the boundary of the pillar, serving as the free face for the cutting project; at a vertical height of half the height of the middle section, a segmented transport roadway is excavated along the strike of the ore body to the boundary of the pillar, serving as the free face for the lower layer cutting project; on the middle section transport roadway within the vein, a layered connecting roadway is excavated inclined upwards with a slope controlled below 15%, and then, adjacent to the bottom pillar, an upper layer cutting roadway is excavated along the strike of the ore body to the boundary of the pillar, serving as the free face for the upper layer cutting project; on the segmented transport roadway, an upper layer cutting roadway is excavated inclined upwards to the boundary of the pillar, serving as the free face for the lower layer cutting project.

[0015] Furthermore, in step S3, the mining area is divided into strips of two specifications: 3m~5m wide and 6m~8m wide, and arranged at intervals. The strips are arranged in a pseudo-inclined manner, with the inclination direction consistent with the mining area, and serve as the mining face.

[0016] Furthermore, the mining operation is carried out in two steps, with each layer being mined in layers. First, 3m-5m strips are mined, followed by 6m-8m strips, following the mining sequence of mining the lower layer first and then the upper layer. Each layer is backfilled in a timely manner after mining. After the lower layer is completely mined and backfilled and the backfill body reaches the allowable strength, the upper layer ore body is mined. After the entire stope is mined and backfilled, the inter-stope pillars are designed to be recovered.

[0017] Furthermore, shallow-hole drilling rigs are used for ore extraction, with borehole depths of 2.5m to 3.0m and borehole spacing of 1.0m to 1.5m. Manual charging and digital detonators are used for detonation. The ore block size is controlled within 350mm, and individual large blocks are subjected to secondary crushing in the stope. The ore extraction equipment uses a shovel to shovel the ore to the inclined ramp and loading level roadway or the segmented transport roadway, load it onto ore trucks, and finally transport it out through the intermediate transport level roadway.

[0018] Furthermore, in step S4, fresh air enters the mining area from the mid-section transport roadway through the mining area ramp, the lower layer loading roadway, the segment transport roadway, the layer connecting roadway, and the upper layer cutting roadway. After washing the working face, the polluted air is extracted by the ventilation duct and collected in the mining area ramp and discharged to the surface through the upper and middle section return air roadway. For mining faces with poor ventilation, local fans are used to enhance ventilation.

[0019] Furthermore, in step S5, to prevent falling rocks, roof roughening operations must be carried out immediately after blasting and ventilation; after the lower layer mining is completed, shotcrete support is adopted, with a shotcrete thickness of 80mm~100mm; for unstable roofs, after the upper layer mining is completed, rock bolts are used for roof control, with a length of 1.5m~2.5m, a grid size of 1.0m×1.0m, and long and short rock bolts are arranged alternately.

[0020] Furthermore, in step S6, the entrances to the goaf are first sealed with filling retaining walls. The filling pipeline is then introduced into the mining area from the upper and middle sections along the mining slope for filling. Before filling, filling retaining walls are erected, and drainage outlets are left to discharge overflow water. A filling opening with a width of 0.8m to 1.5m is drilled in the top pillar of each strip, and the filling pipeline is installed to the filling opening. The filling material is leveled by its own weight until the entire strip is filled. When filling the lower layer, high-strength manufactured sand is used for filling the 3m to 5m and 6m to 8m strips, and the strength of the cemented filling material is required to be no less than 2MPa. When filling the upper layer, high-strength manufactured sand is used for filling the 3m to 5m strip, and the strength is required to be no less than 2MPa. The filling material for the 6m to 8m strip is low-strength filling mortar, and the filling material only needs to meet the dewatering requirements.

[0021] Furthermore, the slope of the ramp and the strip is less than the maximum climbing slope of the mining equipment.

[0022] In summary, this application includes the following beneficial technical effects:

[0023] The pseudo-inclined multi-layer strip mining method for gently inclined medium-thick underground sedimentary bauxite using the above-mentioned technical solution has four outstanding advantages: (1) Compared with the strip arrangement along the dip of the ore body, the pseudo-inclined arrangement of the stope strip reduces the slope of the strip, facilitates the use of mining equipment, and greatly improves the ore extraction efficiency of the stope; (2) The intermediate development, preparation and cutting works are all arranged in the vein, and the ore is mined and cut, which greatly reduces the production cost; (3) The medium-thick ore body is divided into upper and lower layers for mining. The lower layer is mined first, and the upper layer is mined after the filling is completed, which avoids the void area being too large and greatly improves the safety; (4) Compared with the strip along the strike, the pseudo-inclined strip filling can make full use of the self-weight of the filling body for leveling, ensuring good filling and roof connection, and high safety. Attached Figure Description

[0024] Figure 1 This is a front view of the mining method of the present invention;

[0025] Figure 2 The mining method of this invention follows Figure 1 Sectional view along line II-II;

[0026] Figure 3 This is a schematic diagram illustrating the calculation of the pseudo-tilt angle in this invention.

[0027] Explanation of reference numerals in the attached figures:

[0028] 1. Mid-section transport roadway within the vein; 2. Sloping roadway in the mining area; 3. Roof pillar; 4. Bottom pillar; 5. Interstitial pillar; 6. Backfill body; 7. Lower layer loading roadway; 8. Segmented transport roadway; 9. Upper layer cutting roadway; 10. Layered connecting roadway; 11. Anchor bolt; 12. Blasting hole; 13. Ore pile; 14. Ventilation duct; 15. Backfill retaining wall; 16. Backfill opening; 17. 3m~5m strip; 18. 6m~8m strip; 19. Pseudo-inclined roadway. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0030] This invention provides a method for pseudo-dipping multi-layer strip mining of gently dipping, medium-thickness subsurface sedimentary bauxite, comprising the following steps:

[0031] S1, Mining Area Layout

[0032] The gently dipping, medium-thick bauxite ore is divided into different intermediate sections by a mid-section transport roadway 1 located near the footwall of the ore body. Roof pillars 3 and bottom pillars 4 are reserved between the intermediate sections. Within each intermediate section, mining areas are divided along the strike of the ore body, with inter-mining pillars 5 reserved between them. Mining areas are further divided into blocks, and mining is organized using these blocks as the basic unit of recovery. Both the mining areas and the blocks are pseudo-dipping, and their pseudo-dipping directions are consistent. The maximum angle between the pseudo-dipping and the horizontal plane is... In the formula, α is the dip angle of the ore body, and β is the maximum allowable slope angle for the mining equipment; the height of the middle section is 20m~40m, the length of the mining area along the strike direction is 80m~150m, the width of the top pillar 3 and bottom pillar 4 is 8m~12m, and the horizontal width of the inter-pillar 5 is 3m~5m. The specific width of the top pillar 3, bottom pillar 4 and inter-pillar 5 is related to the stability of the roof. When the roof stability is good, a smaller value is taken, and when the stability is poor, a larger value is taken.

[0033] S2, preparation and cutting engineering

[0034] From the middle section transport roadway 1 within the vein, the mining area inclined roadway 2 is excavated. The mining area inclined roadway is arranged with a pseudo-inclination, and the pseudo-inclination direction is consistent with the mining area. It serves as a connecting roadway for personnel and equipment to enter and exit the mining area, and also as a ventilation roadway. On the mining area inclined roadway 2, at a distance of 6m to 8m from the bottom pillar 4 of the mining area, a lower layer loading horizontal roadway 7 is excavated along the strike direction of the ore body to the boundary of the inter-pillar 5, serving as the free face for the cutting project. At a vertical height of half the height of the middle section, a segmented transport horizontal roadway 8 is excavated along the strike direction of the ore body to the side of the inter-pillar 5. At the boundary, serving as the free face for the lower layer cutting project; on the middle section transport roadway 1 within the vein, a layered connecting roadway 10 is excavated upward at an inclined angle, with the slope controlled below 15% to facilitate the passage of mining equipment. Then, adjacent to the bottom pillar 4, an upper layer cutting horizontal roadway 9 is excavated along the strike direction of the ore body to the boundary of the inter-pillar 5, serving as the free face for the upper layer cutting project; on the segmented transport horizontal roadway 8, an upper layer cutting horizontal roadway 9 is excavated upward at an inclined angle to the boundary of the inter-pillar 5, serving as the free face for the lower layer cutting project;

[0035] S3, mining project

[0036] The mining area is divided into two strips, 3m-5m wide (17) and 6m-8m wide (18), arranged alternately. Strips 17 and 18 are pseudo-inclined, with the included angle matching the slope of the mining area (2), serving as the working face. The mining operation employs a two-step, layered approach, using a shallow-hole drilling rig for ore extraction. The blast holes (12) are 2.5m-3.0m deep, spaced 1.0m-1.5m apart, and detonated manually with digital detonators. Ore block size is controlled to within 350mm; larger blocks are partially removed within the mining area. Secondary crushing; the ore extraction equipment uses a shovel to shovel the ore to the inclined ramp 2 of the mining area and the lower layer loading level roadway, the upper layer cutting level roadway 9 or the segmented transport level roadway 8, and load it onto the ore trucks, which are then transported out of the mining area through the middle section transport roadway 1 within the vein; the strip mining sequence is to mine the 3m~5m strip 17 first and then the 6m~8m strip 18, following the mining sequence of mining the lower layer first and then the upper layer. After the lower layer is completely mined and filled and the filling body reaches the allowable strength, the upper layer ore body is then mined; after the entire mining area is mined and filled, the inter-mining pillar 5 is designed to be recovered;

[0037] S4, Mining Ventilation

[0038] Fresh air enters the stope from the middle section transport roadway 1 within the vein, via the mining area ramp 2, the lower layer loading roadway 7, the segmented transport roadway 8, the layered connecting roadway 10, and the upper layered cutting roadway 9. After washing the working face, the polluted air is extracted and compressed by the ventilation duct 14, which has a diameter of 300mm~500mm. The air is then collected in the mining area ramp 2 and discharged to the surface through the upper and middle section return air roadway. For mining faces with poor ventilation, local fans are considered to enhance ventilation.

[0039] S5, Management of the Mining Roof

[0040] To prevent falling rocks, roof roughening operations should be carried out immediately after blasting and ventilation; after the lower layer is mined, shotcrete support should be used, with a shotcrete thickness of 80mm~100mm; for unstable roofs, after the upper layer is mined, anchor bolt 11 should be used to control the roof, with anchor bolt 11 length of 1.5m~2.5m, grid size of 1.0m×1.0m, and long and short anchor bolts arranged alternately.

[0041] S6, Void Filling

[0042] First, seal all passageways leading to the goaf with filling retaining walls 15. Then, from the upper and middle sections, insert the filling pipeline into the mining area along the inclined slope 2 of the mining area for filling. Before filling, the filling retaining wall 15 should be erected and a drainage outlet should be left to discharge overflow water. In the top pillar 3 at the top of the 3m~5m strip 17 and the 6m~8m strip 18, a filling opening 16 with a width of 0.8m~1.5m should be drilled. The filling pipeline should be installed at the filling opening 16 and leveled by the weight of the filling body 6 until the entire strip is filled. During the lower layer mining and backfilling, the 3m~5m strip 17 in the first step and the 6m~8m strip 18 in the second step are filled with high-strength manufactured sand backfill 6, and the strength of the cemented backfill is required to be no less than 2MPa. During the upper layer mining and backfilling, the 3m~5m strip 17 in the first step is filled with high-strength manufactured sand backfill 6, and the strength is required to be no less than 2MPa. The backfill 6 used for the 6m~8m strip 18 in the second step is low-strength backfill mortar, and the backfill only needs to meet the dewatering requirements.

[0043] The above embodiments have been verified to achieve the following main technical and economic indicators:

[0044] Ore block production capacity: 300~400t / d;

[0045] Impoverishment rate: 8%~10%;

[0046] Loss rate: 12%~14%;

[0047] Cutting-to-slaughter ratio: 3.98 m / kt, 53.37 m 3 / kt.

[0048] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. Other modifications can be easily made by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and shown herein.

Claims

1. A method for pseudo-dipping multi-layer strip mining of gently dipping, medium-thickness underground sedimentary bauxite, characterized in that: Includes the following steps: S1. Stope Layout: The gently dipping, medium-thick, subsurface sedimentary bauxite deposit is divided into different sections by a mid-section transport roadway near the footwall of the ore body. Top and bottom pillars are reserved between the sections. Within each section, mining areas are divided along the strike of the ore body. Inter-pillars are reserved between mining areas, and ore blocks are divided within each mining area. Mining is organized using ore blocks as the basic unit. The inter-pillars, mining areas, and ore blocks are all arranged in a pseudo-dipping pattern, with the pseudo-dipping direction consistent. The maximum angle between the pseudo-dipping and the horizontal plane is [value missing]. In the formula, α is the dip angle of the ore body, and β is the maximum allowable slope angle for the mining equipment; S2. Mining preparation and cutting engineering: Excavate the mining area ramp from the middle section of the transport roadway. The mining area ramp is arranged in a pseudo-inclination, and the inclination direction is consistent with the mining area. S3. Long-term mining project: Divide the mining area into mining strips, which are arranged in a pseudo-dipping direction consistent with the mining area, and serve as long-term mining faces. S4, Mining area ventilation; S5. Management of the mining area roof; S6. Filling the void; In step S3, the mining area is divided into strips of two specifications: 3m~5m and 6m~8m in width, and arranged at intervals. The strips are arranged in a pseudo-inclined manner, with the inclination direction consistent with the mining area, and serve as the mining face. The mining operation is carried out in two steps, with each layer being mined in layers. First, a 3m-5m strip is mined, followed by a 6m-8m strip. The mining order is to mine the lower layer first and then the upper layer. Each layer is backfilled in time after mining. After the lower layer is completely mined and backfilled and the backfill reaches the allowable strength, the upper layer is mined. After the entire stope is mined and backfilled, the inter-stope pillars are designed to be recovered. In step S6, the entrances to the goaf are first sealed with filling retaining walls. The filling pipeline is then introduced into the goaf from the upper-middle section along the slope of the goaf for filling. Before filling, the filling retaining walls are erected, and drainage outlets are left to discharge overflow water. A filling opening with a width of 0.8m to 1.5m is drilled in the top pillar of each strip, and the filling pipeline is installed to the filling opening. The filling material is leveled by its own weight until the entire strip is filled. When filling the lower layer, the 3m to 5m strip and the 6m to 8m strip are filled with high-strength manufactured sand, and the strength of the cemented filling material is required to be no less than 2MPa. When filling the upper layer, the 3m to 5m strip is filled with high-strength manufactured sand, and the strength is required to be no less than 2MPa. The filling material for the 6m to 8m strip is low-strength filling mortar, and the filling material only needs to meet the dewatering requirements.

2. The pseudo-dipping multi-layer strip mining method for gently dipping, medium-thick underground sedimentary bauxite deposits as described in claim 1, characterized in that: The mining method is used for gently dipping, medium-thickness underground sedimentary bauxite deposits with a dip angle of 9° to 25°.

3. The method for pseudo-dipping multi-layer strip mining of gently dipping, medium-thick underground sedimentary bauxite deposits according to claim 1, characterized in that: In step S2, the mining area ramp serves as a connecting passage for personnel and equipment to enter and exit the mining area, and also as an air intake passage.

4. The method for pseudo-dipping multi-layer strip mining of gently dipping, medium-thick underground sedimentary bauxite deposits according to claim 3, characterized in that: On the inclined slope of the mining area, 6m to 8m from the bottom plate of the ore block, a lower layer loading roadway is excavated along the strike of the ore body to the boundary of the pillar, serving as the free face for the cutting project; at a vertical height of half the height of the middle section, a segmented transport roadway is excavated along the strike of the ore body to the boundary of the pillar, serving as the free face for the lower layer cutting project; on the middle section transport roadway within the vein, a layered connecting roadway is excavated inclined upwards with a slope controlled below 15%, and then, adjacent to the bottom pillar, an upper layer cutting roadway is excavated along the strike of the ore body to the boundary of the pillar, serving as the free face for the upper layer cutting project; on the segmented transport roadway, an upper layer cutting roadway is excavated inclined upwards to the boundary of the pillar, serving as the free face for the lower layer cutting project.

5. The method for pseudo-dipping multi-layer strip mining of gently dipping, medium-thick underground sedimentary bauxite deposits according to claim 1, characterized in that: Shallow-hole drilling rigs are used for ore extraction, with blast hole depths of 2.5m to 3.0m and blast hole spacing of 1.0m to 1.5m. Manual charging and digital detonators are used for detonation. The ore block size is controlled within 350mm, and individual large blocks are subjected to secondary crushing in the stope. The ore is shoveled by a loader to the inclined ramp and loading level roadway or segmented transport roadway, loaded onto ore trucks, and finally transported out through the intermediate transport level roadway.

6. The method for pseudo-dipping multi-layer strip mining of gently dipping, medium-thick underground sedimentary bauxite deposits according to claim 1, characterized in that: In step S4, fresh air enters the mining area from the mid-section transport roadway through the mining area ramp, the lower layer loading roadway, the segmented transport roadway, the layered connecting roadway, and the upper layer cutting roadway. After washing the working face, the polluted air is extracted by the ventilation duct and collected in the mining area ramp and discharged to the surface through the upper and middle section return air roadway. For mining faces with poor ventilation, local fans are used to enhance ventilation.

7. The method for pseudo-dipping multi-layer strip mining of gently dipping, medium-thick underground sedimentary bauxite according to claim 5, characterized in that: In step S5, to prevent falling rocks, roof roughening operations should be carried out immediately after blasting and ventilation; after the lower layer is mined, shotcrete support is used, with a shotcrete thickness of 80mm~100mm; for unstable roofs, after the upper layer is mined, rock bolts are used to control the roof, with a length of 1.5m~2.5m, a grid size of 1.0m×1.0m, and long and short rock bolts are arranged alternately.

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