High-efficiency recovery method for phosphate ore pillar with interlayer between upper and lower filling bodies

Abstract

This invention belongs to the field of phosphate deposit mining technology, specifically relating to a method for the efficient recovery of phosphate rock pillars containing interlayers between upper and lower backfill bodies. Addressing the hazard of the interlayer and upper backfill body being suspended during the recovery of phosphate rock pillars containing interlayers between upper and lower backfill bodies, this invention proposes constructing a vein-side tunnel along the strike of the interlayer, and using this vein-side tunnel as a foundation for constructing interlayer boreholes and pre-splitting boreholes. These boreholes fracture the interlayer and remove waste rock, thus eliminating the interlayer hazard. After removing the interlayer, the ore blocks are pre-divided using pre-splitting boreholes, ensuring that the weight of the ore blocks is almost entirely distributed across the lower backfill body. This maximizes the compression of the lower backfill body by the ore blocks before recovery, allowing for timely construction of a cushion layer between the divided ore blocks and the upper backfill body to support the upper backfill body and prevent its subsidence and damage, thus eliminating the upper backfill hazard. Finally, the space created by clearing the interlayer serves as supplementary space for the simultaneous recovery of ore from both sides of the interlayer, significantly improving recovery efficiency.

Description

Technical Field

[0001] This invention belongs to the field of phosphate deposit mining technology, specifically relating to a method for efficient recovery of interlayered phosphate rock pillars between upper and lower filling bodies. Background Technology

[0002] The Wengfu Phosphate Mine's Datang section contains two ore layers, A and B, with a dip angle of 85°. Layer A has an average thickness of 12.5m, and layer B has an average thickness of 18.5m. Between layers A and B is an interlayer (rock strata) approximately 3m thick. The Datang section is mined using the open-cut and subsequent backfilling method. The 1130 section has been fully mined. The designed height of the 1130 section is 70m, including a 15m pillar height ranging from 1130 to 1145m; the mined ore body height is 55m, ranging from 1145 to 1200m. The estimated ore volume of the 1130 pillar is 1.1 million tons, possessing significant recovery value.

[0003] The lower part of the 1130 section is designed as the 1060 section, with an elevation range of 1060-1130m. Currently, some areas of the 1060 section have been mined, with the mined body height reaching 55m and an elevation range of 1075-1130m. For the unmined areas of the 1060 section, in order to recover the pillars of the 1130 section, it is proposed to plan and mine the pillars of the 1030 section together with the 1060 section. The mining method can refer to the patent "A staged open space subsequent backfilling mining method for the coordinated use of pillars and ore blocks in phosphate deposits (authorization announcement number: CN119957224B)".

[0004] However, for the areas in section 1060 that have already been mined, such as Figure 1As shown, the 1130 mid-section bottom column is located below the lower 1:4 filling body 2 of the 1030 mid-section and above the upper 1:6 filling body 5 of the 1060 mid-section. The upper 1:6 filling body 5 of the 1060 mid-section is retracted due to water seepage, resulting in a suspended area of ​​the 1130 bottom column. Under the action of gravity, the ore layer a of the 1130 bottom column exerts pressure on its bottom plate 1, causing it to tend to slide downwards along the bottom plate 1, creating gaps between the ore layer a of the 1130 bottom column and the interlayer 3 and the lower 1:4 filling body 2 of the 1030 mid-section; while under the action of gravity, the ore layer b of the 1130 bottom column exerts pressure on its interlayer 3, causing it to tend to slide downwards along the interlayer 3, creating gaps between the ore layer b of the 1130 bottom column and the top plate 4 and the lower 1:4 filling body 2 of the 1030 mid-section. For interlayer 3, which has a relatively small thickness, there are gaps on its bottom plate side and the top plate side is subjected to the force of the 1130 bottom pillar b ore layer, which is prone to fracture. Especially when the 1130 bottom pillar a ore layer is being mined, a large area of ​​the bottom plate side of the interlayer is exposed, and it is more likely to fracture and collapse under the action of the 1130 bottom pillar b ore layer, thus causing dangerous accidents and also leading to an increase in the gangue content in the ore. Furthermore, during the recovery of the 1130 bottom pillar, the ore layers a and b of the 1130 bottom pillar awaiting recovery are prone to falling as a whole onto the upper 1:6 filling body 5 of the lower 1060 middle section, continuously compressing the upper 1:6 filling body 5 of the lower 1060 middle section. This results in a large gap being formed between the 1130 bottom pillar and the lower 1:4 filling body 2 of the upper 1030 middle section, causing it to be suspended. During the mining of the 1130 bottom pillar, the lower 1:4 filling body 2 of the 1030 middle section is prone to damage, and in severe cases, it may collapse into the mining area, causing casualties.

[0005] Therefore, how to reduce the danger caused by interlayer 3 during the mining process, and avoid the danger caused by the continuous compression of the upper 1:6 filling body 5 in the lower 1060 section leading to the suspension of the lower 1:4 filling body 2 in the 1030 section, and safely and efficiently recover the bottom pillar of the 1030 section, has become an urgent problem to be solved by the mine. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes a method for the efficient recovery of bottom columns in phosphate mines with interlayers between upper and lower filling bodies. This method is applicable to steeply inclined phosphate mines, where one side of the interlayer consists of ore layer A and the bottom plate, and the other side consists of ore layer B and the top plate. The bottom column is filled with filling bodies both above and below it. The method includes the following steps: S1: Prepare to arrange the upper and lower plate stage transport level along the direction; prepare to connect the upper and lower plate stage transport level with the through-path level; S2: The construction interlayer connects two cross-vein horizontal tunnels along the vein roadway, dividing the bottom column between the two cross-vein horizontal tunnels into several ore blocks along the strike; from the interlayer upward along the vein roadway, interlayer boreholes are constructed in the interlayer, and several rows of fan-shaped pre-splitting boreholes are constructed on both sides of the horizontal bottom column. The fan-shaped pre-splitting boreholes are constructed at intervals along the strike at the boundary of adjacent ore blocks; the interlayer is fractured based on the interlayer boreholes, and the waste rock in the interlayer is transported out. S3: Use pre-splitting boreholes to sequentially divide each mineral block along the strike to make the mineral blocks independent; construct a cushion layer between the independent mineral blocks and the upper filling body; S4: Recover each ore block sequentially along the direction, and recover the ore blocks of the a and b ore layers on the same horizontal direction at the same time.

[0007] In step S1, the upper stage transport level, lower stage transport level, and cross-cutting level are the upper stage transport level, lower stage transport level, and cross-cutting level used during the mining of the middle section where the bottom pillar is located. The floor of the upper stage transport level, lower stage transport level, and cross-cutting level is at the same elevation as the bottom pillar floor.

[0008] Preferably, in step S2, the interlayer is constructed along the direction of the vein tunnel at the bottom of the interlayer; the distance between the two vein tunnels is not less than 200m.

[0009] Preferably, in step S2, the interlayer drilling is a bedding borehole, arranged at intervals along the strike; the interlayer drilling is carried out to near the upper elevation of the bottom column, and the interlayer is fractured by hydraulic fracturing or blasting based on the interlayer drilling.

[0010] Preferably, in step S2, the length of the ore block is the thickness of the entire base pillar, the height is the height of the entire base pillar, and the width along the direction is 12-15m.

[0011] Preferably, in step S2, a vein pillar is also provided between the ore block and the vein tunnel; rows of fan-shaped pre-splitting boreholes are also constructed at the boundary between the ore block and the vein pillar. The vein pillar is part of the base pillar, with a length equal to the thickness of the entire base pillar, a height equal to the height of the entire base pillar, and a width of 2-5m along the strike.

[0012] Preferably, in step S3, each segmented ore block moves downward under the action of gravity and compresses the lower filling body, increasing the gap between the ore block and the upper filling body; and the gap between the ore block of layer b and the top plate also increases.

[0013] Preferably, in step S3, following the ore block segmentation work, the bottom plate protrusions in the interlayer along the vein are removed.

[0014] Preferably, in step S3, the cushion layer includes wooden boards or a combination of wooden boards and filling slurry, and the wooden boards or the combination of wooden boards and filling slurry are used to fill the gap between the segmented ore blocks and the upper filling body.

[0015] Preferably, in step S3, wooden boards are also supported at the top of the expanded interlayer along the vein.

[0016] Preferably, in step S3, if the strength of the top plate is low, appropriate filling slurry is injected between the top plate and the ore block of layer b.

[0017] Preferably, in step S3, the filling slurry is a thick cementitious slurry.

[0018] Preferably, in step S4, a rock drilling tunnel is first excavated from the interlayer along the vein tunnel to the a-layer ore block and the b-layer ore block on both sides laterally. The rock drilling tunnel is located in the middle of the strike of the ore block and is constructed along the bottom of the ore block.

[0019] Preferably, in step S4, the rock drilling roadway is advanced along the strike direction, and ore-dropping boreholes are constructed in the rock drilling roadway from the interlayer along the vein roadway to both sides in the transverse direction. The ore-dropping boreholes are constructed in several rows at intervals along the transverse direction, and each row is arranged in a fan shape.

[0020] Preferably, in step S4, the delayed ore-cutting drilling process along the strike is used to carry out mining and backfilling work on the ore block.

[0021] Preferably, in step S4, the enlarged interlayer along the vein is used as the compensation space, and ore is blasted out from the interlayer along the vein in both lateral directions through the ore-dropping boreholes in the rock-drilling tunnel.

[0022] Preferably, in step S4, the fallen ore is transported out sequentially through the interlayer vein tunnel, the vein horizontal tunnel, and the lower plate stage transport horizontal tunnel.

[0023] Preferably, in step S4, when drilling a ore-dropping hole for the preceding ore block along the strike, the adjacent following ore block is blasted through the ore-dropping hole and filled after forming a goaf; after the filling material solidifies to the required strength, the preceding ore block is blasted for ore-dropping.

[0024] Preferably, in step S4, after the ore is dropped and transported, the original ore block forms a goaf. A filling retaining wall is constructed to block the drilling roadway at the upper boundary and the drilling roadway at the lower boundary. A filling curtain wall is suspended at the interlayer along the vein roadway at the boundary of the goaf, thereby sealing the entire goaf. After sealing the goaf, grouting is performed to fill the goaf.

[0025] The inventive points and beneficial technical effects of this invention are as follows: Addressing the hazard of the interlayer and upper backfill being suspended during the recovery of a phosphate rock pillar containing an interlayer between upper and lower backfill bodies, this invention proposes constructing an interlayer along the strike of the vein, and using this vein as a foundation for constructing interlayer boreholes and pre-splitting boreholes. These boreholes fracture the interlayer and remove waste rock, thus eliminating the interlayer hazard. After removing the interlayer, the pre-splitting boreholes pre-divide the ore blocks, ensuring that the weight of the blocks is almost entirely distributed across the lower backfill body. This maximizes the compression of the lower backfill body by the ore blocks before recovery, allowing for timely construction of a cushion layer between the divided blocks and the upper backfill body to support the upper backfill and prevent its subsidence and damage, thus eliminating the upper backfill hazard. Finally, the space created by clearing the interlayer serves as supplementary space for the simultaneous recovery of ore from both sides of the interlayer, significantly improving recovery efficiency. Attached Figure Description

[0026] Figure 1 This is a schematic cross-sectional view of the bottom pillar along the dip direction of the ore layer in this invention; Figure 2 This is a schematic diagram of the planar planning of the high-efficiency bottom column recycling method of the present invention; Figure 3 This is a schematic cross-sectional view of the sandwich treatment and pre-fracturing of the bottom column in this invention; Figure 4 This is a schematic diagram of the sandwich treatment and pre-fracturing of the bottom column in this invention; Figure 5 This is a schematic diagram of the inclined cross-section after the sandwich treatment and pre-fracture of the bottom column according to the present invention; Figure 6 This is a schematic cross-sectional view of the construction and protrusion treatment of the top pad layer of the bottom column in this invention; Figure 7 A schematic diagram of the interlayer treatment, the pre-cracked bottom column, and the protrusion treatment of the present invention. Figure 8 This is a schematic cross-sectional view of the efficient recovery process of the bottom column in this invention; Figure 9 This is a schematic diagram of the efficient recovery process of the bottom column in this invention (ore falling). Figure 10 This is a schematic diagram of the efficient recycling process of the bottom column of the present invention (filling).

[0027] Figure 5-6 , Figure 8 The blocks marked with red borders are the locations of the individual blocks after the division. Figure 5 The black lines mark the original location of the ore block, creating a comparison of the positions before and after the block was divided.

[0028] In the diagram, a-1130 middle section bottom pillar a ore layer; b-1130 middle section bottom pillar b ore layer; 1-bottom plate, 2-upper filling body; 3-interlayer; 4-roof plate; 5-lower filling body; 6-footing stage transport tunnel; 7-footing stage transport tunnel; 8-vein tunnel; 9-vein pillar; 10-ore block; 11-interlayer along-vein tunnel; 12-interlayer borehole; 13-pre-splitting borehole; 14-protrusion; 15-subbase; 16-falling ore borehole; 17-rock drilling tunnel; 18-filled retaining wall; 19-filled curtain; 20-filled body. Detailed Implementation

[0029] In response to the technical problems pointed out in the background section, the specific implementation method will be based on the bottom pillar of the 1130 section of the Datang section of the Wengfu phosphate mine as an example, combined with the attached... Figure 1-10 The technical solution of the present invention will be further explained below.

[0030] It should be stated that the technical problem described in the background of this invention is illustrated using the Datang section of the Wengfu phosphate mine as an example, particularly its 1130 mid-section bottom pillar. The specific implementation method also uses the 1130 mid-section bottom pillar of the Datang section of the Wengfu phosphate mine as an example to introduce the technical solution of this invention. However, those skilled in the art should be able to conclude from this specific case that ore bottom pillars with the same or similar conditions should also have the same technical problem. That is, the technical problem in this invention is only introduced and explained using a specific example, but it is not limited to this specific example; the specific implementation method is the same.

[0031] like Figure 1 As shown, the Wengfu Phosphate Mine's Datang section contains two ore layers, a and b, with a dip angle of 85°. Between layers a and b is an interlayer 3 approximately 3 meters thick. Ore layer a has an average thickness of 12.5 meters, located on the footwall side, with a base plate 1 at the bottom and interlayer 3 at the top. Ore layer b has an average thickness of 18.5 meters, located on the hanging wall side, with interlayer 3 at the bottom and a roof plate 4 at the top. The 1130-section central pillar is 15 meters high, with the upper part being the upper backfill 2 formed by ore mining in the 1130-section (a 1:4 backfill) and the lower part being the lower backfill 5 formed by ore mining in the 1060-section (a 1:6 backfill). Due to the gravity of the central pillar, as well as the shrinkage of the lower backfill 5 due to water seepage and the compression of the central pillar, interlayer 3 is prone to forming unstable rocks during the recovery of the central pillar in the 1130-section, and the upper backfill 2 is prone to large-area suspension and collapse. In addition, the long, narrow base column is prone to impact when it breaks.

[0032] In order to recover the bottom column of the 1130 section, such as Figure 1-10 As shown, this invention proposes a method for efficient recovery of phosphate rock bottom pillars containing interlayers between upper and lower filling bodies, comprising the following steps: S1: As Figure 1-4 As shown; the original 1130 middle section upper stage transport level 7, lower stage transport level 6, and cross-cut level 8 were repaired. The cross-cut level 8 passes through the entire a ore layer, b ore layer, and interlayer 3, connecting the upper stage transport level 7 and lower stage transport level 6. The bottom plate elevation of the upper stage transport level 7, lower stage transport level 6, and cross-cut level 8 is consistent with the bottom plate elevation of the 1130 middle section pillar, which is 1130m, and the rectangular cross-section size is 4×4m. The upper stage transport level 7 and lower stage transport level 6 are arranged along the strike of the ore layer, and the cross-cut level 8 is arranged perpendicular to the strike of the ore layer.

[0033] S2: As Figure 1-4As shown; a mezzanine along the vein 11 is constructed from one vein level 8 to another vein level 8. The mezzanine along the vein 11 is constructed along the direction at the bottom of the mezzanine 3 at an elevation of 1130m, with a rectangular cross-section of 4×4m. The distance between the two vein level 8 is preferably not less than 200m. From the interlayer along the vein 11 upwards, interlayer boreholes 12 in the form of bedding planes are constructed in the interlayer 3. The interlayer boreholes 12 are arranged at intervals along the strike. Along the strike, from the interlayer along the vein 11 to the lateral sides of the 1130 middle section bottom pillar a ore layer and the 1130 middle section bottom pillar b ore layer, several rows of fan-shaped pre-splitting boreholes 13 are constructed at intervals. The rows of fan-shaped pre-splitting boreholes 13 are constructed at the boundary of adjacent ore blocks 10 or at the boundary of ore block 10 and through-vein pillar 9. The through-vein pillar 9 is adjacent to the through-vein horizontal duct 8 on one side of the strike and to the ore block 10 on the other side of the strike. The through-vein pillar 9 is part of the bottom pillar, with a length equal to the thickness of the entire bottom pillar, a height equal to the height of the entire bottom pillar, and a width of 2-5m along the strike. Between two through-vein pillars 9 are several ore blocks 10. The length of the ore block 10 is equal to the thickness of the entire bottom pillar, the height of the ore block 10, and a width of 12-15m along the strike. Only some ore blocks 10 are shown in the attached figure. The interlayer borehole 12 is constructed to the vicinity of the upper elevation of the bottom column. Based on the interlayer borehole 12, the interlayer 3 is fractured by fracturing or blasting (it can be fractured and transported in stages along the strike). The fallen interlayer waste rock is transported out in sequence through the interlayer vein tunnel 11, the vein level tunnel 8, and the lower stage transport level tunnel 6, thus eliminating the danger of the interlayer 3. The height of the interlayer vein tunnel 11 is expanded to the height of the upper filling body 2.

[0034] S3: As Figure 5-7 As shown, along the direction from one cross-vein tunnel 8 to another cross-vein tunnel 8, the ore blocks 10 are sequentially divided using pre-splitting boreholes 13, so that each ore block 10 is separated from the adjacent ore blocks 10 or cross-vein pillars 9. Each ore block 10 after division moves downward under the action of gravity. For the ore block 10 of the 1130 bottom pillar a ore layer, it slides down along the bottom plate 1 under the action of gravity and compresses the lower filling body 5, thereby increasing the gap between the ore block 10 of the 1130 bottom pillar a ore layer and the upper filling body 2. For the ore block 10 of the 1130 bottom pillar b ore layer, it moves vertically downward under the action of gravity and compresses the lower filling body 5, thereby increasing the gap between the ore block 10 of the 1130 bottom pillar b ore layer and the upper filling body 2 and the top plate 1.

[0035] Along the direction from one cross-vein level 8 to another cross-vein level 8, closely following the segmentation work of the ore block 10, for example, at a interval of one ore block 10, or about 10m later, remove the bottom plate protrusion 14 in the interlayer cross-vein level 11 so that it is flush with the bottom surface of the ore blocks 10 on both sides laterally, or, considering that the ore block 10 may continue to compress the filling body 5, remove the bottom plate protrusion 14 in the interlayer cross-vein level 11 so that the bottom plate of the interlayer cross-vein level 11 is slightly lower than the bottom surface of the ore block 10.

[0036] Following the removal of the floor protrusion 14 from one cross-vein level 8 to another, and for example, at intervals of one ore block 10 or about 10 meters later, a cushion layer 15 is constructed between the divided ore block 10 and the upper filling body 2. The cushion layer 15 consists of wooden planks or a combination of wooden planks and filling grout. The wooden planks or the combination of wooden planks and filling grout are used to fill the gap between the divided ore block 10 and the upper filling body 2, preventing a large-area overhang crack in the upper filling body 2 and its collapse into the stope during the subsequent recovery of the ore block 10. Due to the high construction position, scaffolding that can move along the enlarged interlayer and the direction of the cross-vein level 11 can be erected to assist in the construction.

[0037] Preferably, wooden planks are also supported at the top of the enlarged interlayer along the vein 11 to reduce the risk of the crushed stone of the upper filling body 2 falling into the interlayer along the vein 11.

[0038] Preferably, the filling slurry is a thick cementitious slurry (such as cement slurry). Since the weight of the ore block 10 can be almost completely applied to the lower filling body 5, the gap between the ore block 10 and the upper filling body 2 will be larger, which will facilitate the flow of the thick cementitious slurry (such as cement slurry). The thick cementitious slurry (such as cement slurry) can reduce the slurry diffusion radius, which is conducive to controlling the flow range and avoiding loss from non-grouting gaps (such as gaps at the boundary between adjacent ore blocks).

[0039] By pre-dividing the ore blocks 10, the weight of the ore blocks 10 can be almost entirely applied to the lower filling body 5, thereby maximizing the compression of the lower filling body 5 by the ore blocks 10 before recycling. This allows for the timely construction of a cushion layer 15 between the divided ore blocks 10 and the upper filling body 2, which in turn supports the upper filling body 2 and prevents it from sinking and being damaged.

[0040] Furthermore, depending on the hardness of the top plate 1, if the strength of the top plate 1 is low, appropriate filling grout can be injected between the top plate 1 and the ore block 10 of the bottom pillar b layer in the 1130 section. The filling grout is preferably a thick cementitious grout (such as cement grout).

[0041] S4: As Figure 8-10 As shown, along the direction from one cross-cutting tunnel 8 to another, each ore block 10 is recovered sequentially, and the ore blocks 10 of the 1130 middle section bottom pillar a ore layer and the 1130 middle section bottom pillar b ore layer on the same transverse side are recovered simultaneously. Details are as follows: First, drilling tunnels 17 are excavated from the interlayer along the vein tunnel 11 to the ore blocks 10 of the 1130 middle section bottom pillar a and 1130 middle section bottom pillar b on both sides. The drilling tunnels 17 are located in the middle of the strike of the ore blocks 10 and are constructed along the bottom of the ore blocks 10. The drilling tunnels 17 of the ore blocks 10 of the 1130 middle section bottom pillar a are constructed to the lower stage transport tunnel 6, and the drilling tunnels 17 of the ore blocks 10 of the 1130 middle section bottom pillar b are constructed to the upper stage transport tunnel 7. The tunnels 17 have a rectangular cross section with dimensions of 2-3m in length and 2-3m in width, such as 2m×2m or 3m×2m.

[0042] The drilling roadway 17 is delayed by 1-2 blocks of ore progress. Ore-dropping boreholes 16 are constructed in the drilling roadway 17, arranged in several rows at transverse intervals, each row in a fan shape. In this embodiment, taking a delay of 2 blocks as an example, for instance, if the drilling roadway 17 is currently being drilled for the 4th block of ore, then ore-dropping boreholes 16 are constructed along the 2nd block of ore 10 of the strike. The direction of constructing the ore-dropping boreholes 16 in the drilling roadway 17 is as follows: from the interlayer along the vein roadway 11 towards the hanging wall stage transport roadway 6, each row of ore-dropping boreholes 16 is constructed sequentially in the bottom pillar a ore layer block 10 of the 1130 section; from the interlayer along the vein roadway 11 towards the hanging wall stage transport roadway 7, each row of ore-dropping boreholes 16 is constructed sequentially in the bottom pillar b ore layer block 10 of the 1130 section.

[0043] Along the direction of the delayed ore-dropping borehole 16 construction process, one block progress is carried out for mining and backfilling of ore block 10; using the enlarged interlayer vein roadway 11 as the compensation space (the enlarged interlayer vein roadway 11 acts as a cutting groove), ore is blasted through the ore-dropping borehole 16 in the rock drilling roadway 17. The direction of ore blasting through the ore-dropping borehole 16 in the rock drilling roadway 17 is as follows: from the interlayer vein roadway 11 to the hanging wall stage transport roadway 6, ore block 10 of the bottom pillar a ore layer in the 1130 middle section is blasted through the ore-dropping borehole 16 in sequence; from the interlayer vein roadway 11 to the hanging wall stage transport roadway 7, ore block 10 of the bottom pillar b ore layer in the 1130 middle section is blasted through the ore-dropping borehole 16 in sequence; the dropped ore is transported out sequentially through the interlayer vein roadway 11, the vein roadway 8, and the hanging wall stage transport roadway 6. In this embodiment, the construction process for a lag of one ore block can be understood as follows: For example, if the second ore block along the strike is undergoing ore-dropping drilling 16, then the first ore block 10 along the strike is blasted through ore-dropping drilling 16 and filled after forming a goaf. After ore is dropped and transported, the original ore block forms a goaf. Grouting is performed to fill the goaf in the interlayer vein roadway 11. A filling retaining wall 18 is constructed to seal the drilling roadway 17 at the upper boundary and the drilling roadway 17 at the lower boundary. At the interlayer vein roadway 11 at the strike boundary of the goaf, a filling curtain wall 19 is suspended using scaffolding to close the entire goaf. Two filling curtain walls 19 need to be constructed for the first goaf along the strike, while only one filling curtain wall needs to be constructed for subsequent goafs. After closing the goaf, grouting is performed to fill the goaf with a 1:6 filling material. After the filling body 20 has solidified and reached the required strength, the ore block adjacent to the filling body 20 that has already completed the construction of the ore-dropping borehole 16 is blasted to remove the ore.

[0044] This invention is not limited to the preferred embodiments described above. Anyone can derive other methods in various forms under the guidance of this invention. Any technical solution that is the same as or similar to this application falls within the protection scope of this invention.

Claims

1. A method for efficient recovery of a bottom column in a phosphate mine with interlayers between upper and lower filling bodies, applicable to steeply inclined phosphate mines, wherein one side of the interlayer consists of ore layer A and a bottom plate, and the other side consists of ore layer B and a top plate, and the bottom column is filled with filling bodies both above and below it, characterized in that... Includes the following steps: S1: Prepare to arrange the upper and lower plate stage transport level along the direction; prepare to connect the upper and lower plate stage transport level with the through-path level; S2: The construction interlayer connects two cross-vein horizontal tunnels along the vein roadway, dividing the bottom column between the two cross-vein horizontal tunnels into several ore blocks along the strike; from the interlayer upward along the vein roadway, interlayer boreholes are constructed in the interlayer, and several rows of fan-shaped pre-splitting boreholes are constructed on both sides of the horizontal bottom column. The fan-shaped pre-splitting boreholes are constructed at intervals along the strike at the boundary of adjacent ore blocks; the interlayer is fractured based on the interlayer boreholes, and the waste rock in the interlayer is transported out. S3: Use pre-splitting boreholes to sequentially divide each mineral block along the strike to make the mineral blocks independent; construct a cushion layer between the independent mineral blocks and the upper filling body; S4: Each ore block is recovered sequentially along the strike, and the ore blocks of the a and b ore layers on the same transverse side are recovered simultaneously. This includes: firstly, drilling tunnels are excavated from the interlayer along the vein roadway to the ore blocks of the a and b ore layers on both sides of the transverse side; drilling ore-dropping holes are constructed from the drilling tunnels to the ore blocks; using the enlarged interlayer along the vein roadway as compensation space, ore is blasted out from the interlayer along the vein roadway to both sides of the transverse side in the drilling tunnels through the ore-dropping holes; after the ore is dropped and transported, the original ore block forms a goaf, which is then grouted and filled.

2. The method for efficient recovery of interlayered phosphate rock bottom pillars between upper and lower filling bodies according to claim 1, characterized in that, In step S1, the upper stage transport level, lower stage transport level, and cross-cutting level are the upper stage transport level, lower stage transport level, and cross-cutting level used during the mining of the middle section where the bottom pillar is located. The floor of the upper stage transport level, lower stage transport level, and cross-cutting level is at the same elevation as the bottom pillar floor.

3. The method for efficient recovery of interlayered phosphate rock bottom pillars between upper and lower filling bodies according to claim 1, characterized in that, In step S2, the interlayer is constructed along the direction of the vein tunnel at the bottom of the interlayer; the distance between the two vein tunnels is not less than 200m; And / or, in step S2, the interlayer boreholes are in-between boreholes, arranged at intervals along the strike; the interlayer boreholes are constructed to near the upper elevation of the bottom column, and the interlayer is fractured by fracturing or blasting based on the interlayer boreholes.

4. The method for efficient recovery of interlayered phosphate rock bottom pillars between upper and lower filling bodies according to claim 1 or 3, characterized in that, In step S2, the length of the ore block is the thickness of the entire base pillar, the height is the height of the entire base pillar, and the width along the direction is 12-15m. And / or, in step S2, a cross-vein pillar is also set between the ore block and the cross-vein tunnel; rows of fan-shaped pre-splitting boreholes are also constructed at the boundary between the ore block and the cross-vein pillar, the cross-vein pillar is part of the base pillar, the length is the thickness of the entire base pillar, the height is the height of the entire base pillar, and the width along the strike is 2-5m.

5. The method for efficient recovery of interlayered phosphate rock bottom pillars between upper and lower filling bodies according to claim 1, characterized in that, In step S3, each segmented ore block moves downward under the influence of gravity and compresses the lower filling body, increasing the gap between the ore block and the upper filling body; and the gap between the ore block of layer b and the top plate also increases.

6. The method for efficient recovery of interlayered phosphate rock bottom pillars between upper and lower filling bodies according to claim 5, characterized in that, In step S3, following the ore block segmentation work, the floor protrusions in the interlayer along the vein are removed.

7. The method for efficient recovery of interlayered phosphate rock bottom pillars between upper and lower filling bodies according to claim 5 or 6, characterized in that, In step S3, the cushion layer includes wooden boards or a combination of wooden boards and filling grout, which are used to fill the gaps between the segmented ore blocks and the upper filling body. And / or, in step S3, wooden boards are also supported at the top of the expanded mezzanine along the vein. And / or, in step S3, if the strength of the top plate is low, appropriate filling slurry is injected between the top plate and the ore block of layer b.

8. The method for efficient recovery of interlayered phosphate rock bottom pillars between upper and lower filling bodies according to claim 7, characterized in that, In step S3, the filling slurry is selected as a thick cementitious slurry.

9. The method for efficient recovery of interlayered phosphate rock bottom pillars between upper and lower filling bodies according to claim 8, characterized in that, In step S4, the rock drilling tunnel is located in the middle of the strike of the ore block and is constructed along the bottom of the ore block; And / or, in step S4, the rock drilling roadway is advanced along the direction of the lagging tunnel, and ore-dropping boreholes are constructed in the rock drilling roadway from the interlayer along the vein roadway to both sides in the transverse direction. The ore-dropping boreholes are constructed in several rows at intervals along the transverse direction, and each row is arranged in a fan shape. And / or, in step S4, the delayed ore-falling drilling construction process along the strike is used to carry out mining and backfilling work on the ore block.

10. The method for efficient recovery of interlayered phosphate rock bottom pillars between upper and lower filling bodies according to claim 9, characterized in that, In step S4, the fallen ore is transported out sequentially through the interlayer vein tunnel, the vein horizontal tunnel, and the lower plate stage transport horizontal tunnel; And / or, in step S4, when drilling a ore-dropping hole along the strike of the preceding ore block, the adjacent following ore block is blasted through the ore-dropping hole and filled after the goaf is formed; after the filling body solidifies to the strength requirement, the preceding ore block is blasted for ore-dropping. And / or, in step S4, after the ore is dropped and transported, the original ore block forms a goaf. A filling retaining wall is constructed to block the drilling roadway at the upper boundary and the drilling roadway at the lower boundary. A filling curtain wall is suspended at the interlayer along the vein roadway at the boundary of the goaf, thereby sealing the entire goaf. After sealing the goaf, grouting is performed to fill the goaf.

Images