Phosphorite mining method

Abstract

The invention discloses a phosphorite mining method which comprises the following steps: constructing and cutting an uphill along a top plate of an ore body from a lower layered gate way to an upper layered gate way, and supporting by adopting a resin anchor rod, a reinforcing mesh and a mining anchor cable; cutting groove construction is conducted, medium-length holes are formed in the lower layered gate way, explosives are loaded in the medium-length holes to conduct blasting layer by layer, a cut uphill bottom plate is continuously lowered till an ore body bottom plate is reached, and the cutting grooves are formed; fan-shaped medium-length holes are constructed in the lower layered gate way, a plurality of rows of fan-shaped medium-length holes are formed in the vertical direction, a plurality of holes are formed in each row of fan-shaped medium-length holes in the vertical direction, blasting is conducted with the cutting groove as a vertical free face, and the fan-shaped medium-length holes are blasted in batches; and charging powder in the lower layered roadway, and after blasting, entering a stope by adopting a remote control forklift for ore removal. The vertical free surface blasting technology is adopted for blasting the medium-length holes in batches, and the method has the advantages that the top plate operation safety is improved, the mining period is shortened, and the ore recovery rate is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of phosphate rock mining, and in particular to a phosphate rock mining method. Background Art

[0002] The original design for the phosphate mine used an upward-type, segmented, cemented-fill mining method. The first phase of the project employed intra-vein development, while the second phase employed extra-vein development. This method offers the advantage of a high roof safety factor, but it also exposed a series of problems during actual production. For example, after using shallow holes for manual roof cutting, the support working surface spans a large area, forcing support workers and equipment to work under the large-span roof for extended periods, posing a high safety risk. Manual shallow-hole roof cutting and stope roof anchoring and support operations are time-consuming and costly. Long mining and cutting times result in low stope production efficiency. The steep slope of the triangular ore in the stope floor makes mining difficult, resulting in a low recovery rate in the mine room. The large proportion of mining and cutting work in the mine room makes it difficult to leverage the advantages of medium- and deep-hole mining, resulting in high mining costs. The horizontal fan-shaped hole bottom blasting method used for the horizontal blasting free face is ineffective, resulting in high pyrotechnic consumption and a high rate of large blocks.

[0003] Therefore, there is an urgent need to optimize the mining methods of Xiaogaozhai Phosphate Mine to improve mining operation efficiency, reduce mining costs, and reduce safety risks. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a phosphate rock mining method to solve the problems of low mine recovery rate and high cost in the prior mining method.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] A phosphate rock mining method comprises the following steps:

[0007] Step 1: Cut uphill along the ore body roof from the lower layered level tunnel to the upper layered level tunnel, and use resin anchor rods and mining anchor cables for support;

[0008] Step 2, cutting groove construction, arranging medium-deep holes in the lower layered level tunnel, loading explosives in the medium-deep holes and blasting them layer by layer, so that the cutting uphill bottom plate is continuously lowered until the ore body bottom plate, forming the cutting groove;

[0009] Step 3, constructing fan-shaped medium-long holes in the lower layered level tunnel, wherein the fan-shaped medium-long holes are arranged in multiple rows in the vertical direction, and each row of the fan-shaped medium-long holes has multiple holes arranged in the vertical direction, and blasting is performed with the cutting groove as the vertical free surface, and the fan-shaped medium-long holes are blasted in batches;

[0010] Step 4: Charge the lower layered tunnel with explosives, and use a remote-controlled forklift to enter the stope and mine after blasting.

[0011] As a further improvement of the above technical solution, the width of the cutting groove is 5m, and the depth of the cutting groove is 8-15m.

[0012] As a further improvement of the above technical solution, the depth of the cutting groove is equal to the thickness of the ore body.

[0013] As a further improvement of the above technical solution, 10 rows of medium-deep holes are arranged during the construction of the cutting groove, with 3 holes arranged in each row, and the 10 rows of medium-deep holes are blasted in batches.

[0014] As a further improvement of the above technical solution, the row surface inclination angles of the medium-deep holes in the 1st to 10th rows decrease successively, and the maximum hole depths of the medium-deep holes in the 1st to 10th rows decrease successively.

[0015] As a further improvement of the above technical solution, the inclination angle of the medium-deep holes in the first row is 18°, and the maximum hole depth is 29m; the inclination angle of the medium-deep holes in the tenth row is -23°, and the maximum hole depth is 14m.

[0016] As a further improvement of the above technical solution, the 10 rows of medium-depth holes are blasted three times, the first blast is for the 1st to 3rd rows of medium-depth holes, the second blast is for the 5th to 6th rows of medium-depth holes, and the third blast is for the 7th to 10th rows of medium-depth holes.

[0017] As a further improvement of the above technical solution, each row of the fan-shaped medium-deep holes is arranged with 12 holes in the vertical direction, and blasting is performed with the cutting groove as the vertical free surface, with blasting of two rows of the fan-shaped medium-deep holes each time.

[0018] As a further improvement of the above technical solution, the inclination angle of the arrangement surface of the fan-shaped medium-deep holes is 90°.

[0019] As a further improvement of the above technical solution, in step 2, the cutting groove is constructed by drilling holes in layers with a rock drill, and blasting in stages to lower the bottom plate of the cutting mountain to form the cutting groove.

[0020] The beneficial effects of the present invention are: by cutting up the mountain from the bottom up and strengthening the support, the vertical free surface blasting technology is used to blast medium and deep holes in batches, and combined with a remote-controlled shovel to mine, the problems of high roof support risk, long mining and cutting cycle, and low triangular ore recovery rate in traditional methods are solved. It has the advantages of improving the safety of roof operations, shortening the mining cycle, and increasing the ore recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below with reference to the accompanying drawings and examples.

[0022] Figure 1 This is a schematic cross-sectional view of the mining process in Example 1 of the present invention;

[0023] Figure 2 Schematic diagram of deep hole arrangement in the cutting groove in Example 1 of the present invention;

[0024] Figure 3 Schematic diagram of the arrangement of fan-shaped medium-deep holes in Example 1 of the present invention;

[0025] Figure 4 This is a schematic diagram of the mining plane in Example 3 of the present invention;

[0026] Figure 5 yes Figure 4 Schematic diagram of the cross section of III-III. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the concept, specific structure and technical effects of the present invention in conjunction with the embodiments and drawings, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without paying creative work are within the scope of protection of the present invention. The various technical features in the invention can be combined interchangeably without conflicting with each other.

[0028] Example 1, a phosphate mining method, comprising the following steps:

[0029] Step 1, refer to Figure 1 , from the lower layered level tunnel to the upper layered level tunnel, cut up the mountain along the ore body roof, and use resin anchor rods + steel mesh and mining anchor cables for support;

[0030] Step 2: Cutting groove construction: arrange medium-deep holes in the lower layered level tunnel, load explosives in the medium-deep holes and blast them layer by layer to continuously lower the cutting uphill floor until the ore body floor is formed;

[0031] Step 3: construct fan-shaped medium-long holes in the lower layered level tunnel, wherein the fan-shaped medium-long holes are arranged in multiple rows in the vertical direction, and multiple holes are arranged in each row along the vertical direction, and blasting is performed with the cutting groove as the vertical free surface, and the fan-shaped medium-long holes are blasted in batches;

[0032] Step 4: Charge the lower level tunnel with explosives, and after blasting, use a remote-controlled forklift to enter the stope and mine.

[0033] It can be understood that cutting uphill refers to a channel excavated from the lower layered level tunnel to the upper layered level tunnel along the roof of the ore body, which can be formed by drilling and blasting with a rock drill. This structure provides an initial working space for subsequent cutting groove construction; resin anchor rods and mining anchor cables refer to support materials used to reinforce the surrounding rock, which can be installed by mechanical anchoring or grouting. Its function is to maintain the stability of the cutting uphill and prevent the roof from collapsing.

[0034] A cutting slot is a vertical space created by medium- and long-hole blasting. This is achieved by arranging multiple rows of medium- and long-hole blasting in batches in the lower layered laneway. This structure acts as a vertical free surface, providing an open surface for subsequent fan-shaped medium- and long-hole blasting. Fan-shaped medium- and long-hole blasting refers to multiple rows of drilled holes arranged vertically. These holes are drilled using a rock drill at an angle to the fan-shaped rows, with multiple holes per row. Their purpose is to improve ore crushing efficiency and reduce the rate of large ore through concentrated blasting.

[0035] Remote-controlled shovel mining refers to the use of unmanned equipment to load and transport ore. It can be operated through a wireless remote control system, remote operation or AI autonomous operation. Its function is to prevent people from entering the mining area after blasting and ensure operational safety.

[0036] In the traditional existing phosphate triangular mining process, when using the upward-type segmented cemented filling mining method, manual shallow hole cutting requires the implementation of anchor net support operations under the large-span roof. The exposed area of ​​the support working surface reaches the total span of the mine room, and the workers and equipment are in the roof area without a stable support structure for a long time. The shallow hole cutting process requires the control of the cutting width and span in batches, resulting in a mismatch between the cutting thickness and the actual mining needs of the mine room. When the horizontal fan-shaped medium-deep holes are blasted in the bottom, the free surface shape does not match the hole arrangement method, resulting in insufficient blasting energy utilization and higher-than-expected pyrotechnic material consumption. The triangular mining area of ​​the mine floor is affected by the inclination of the ore body. Conventional horizontal blasting makes it difficult to form an effective crushing zone, and the residual ore cannot be completely recovered.

[0037] For example, within a mine chamber with a 12-meter-thick orebody, workers must construct a 5-meter x 4-meter cut along the orebody roof, using shallow holes to cut the roof in stages to create a 3-meter-thick artificial roof. After cutting the roof, combined support with anchor rods, steel mesh, and cables is implemented. The horizontal span of the support surface reaches 12 meters, leaving the roof rock in a cantilevered state. This shallow hole cutting must be completed in five stages, each 4-meter wide. Each cut requires suspension for anchor mesh support, extending the mining cycle by 2.3 times that of conventional operations.

[0038] Therefore, traditional mining methods involve significant risks, as support personnel and equipment must work under large roof spans for extended periods. Horizontal blasting of the free face using fan-shaped holes arranged horizontally is ineffective, resulting in high blasting power consumption and a high rate of large blocks. Roof removal accounts for 33% of the mine's total volume, while the remaining 67% is achieved using medium- to deep-hole blasting, which hinders the advantages of medium- to deep-hole mining and results in high recovery costs.

[0039] Therefore, when faced with the problems of traditional mining methods, the present invention first considers how to avoid the high risk of large-span roof support operations, while improving cutting efficiency and blasting effects. In traditional mining methods, after cutting up the mountain, manual shallow hole cutting and anchor net support are required, which causes workers to be exposed to the unsupported roof area. In this regard, the present invention attempts to use cutting up the mountain as the starting point for subsequent blasting, and forms cutting grooves through medium-deep hole blasting to replace the original manual cutting process. In order to solve the problem of low efficiency of horizontal free surface blasting, the present invention analyzes the matching of the vertical free surface and the direction of the fan-shaped medium-deep hole arrangement, and finds that when the blast hole arrangement surface forms a vertical relationship with the free surface, the stress wave propagation path can be optimized. In addition, in response to the problem of residual triangular ore in the bottom plate, the present invention proposes to adjust the depth of the cutting groove to the bottom plate of the ore body so that the subsequent blasting covers the full thickness area of ​​the ore body. After comparing multiple schemes, it was finally determined to use the method of forming a vertical free surface by cutting grooves combined with vertically arranged fan-shaped holes to achieve efficient blasting and dropping of ore while eliminating the manual cutting process.

[0040] This invention achieves efficient blasting and ore removal by forming a vertical free surface and vertically arranging fan-shaped holes. The cutting groove design replaces the traditional manual roof cutting process, avoiding high-risk support operations under large-span roofs. The matching of the vertical free surface and the arrangement of fan-shaped medium- and deep-holes optimizes the stress wave propagation path and improves blasting efficiency. Extending the cutting groove to the ore body floor allows subsequent blasting to cover the entire thickness of the ore body, helping to resolve the problem of triangular ore residue in the floor.

[0041] In some embodiments, reference Figure 1 The width of the cutting groove is 5m, the depth of the cutting groove is 8-15m, and the depth of the cutting groove is equal to the thickness of the ore body. Among them, the width of the cutting groove is set to 5m to ensure that a vertical free surface of sufficient width is formed during medium-long hole blasting, which is conducive to rock crushing and ore collapse; the depth of the cutting groove is limited to 8-15m, which matches the thickness of the ore body. It can not only cover the range of the ore body, but also avoid over-excavation or under-excavation, and reduce damage to non-ore rock areas. In specific implementation, the depth range is adjusted according to the actual thickness of the ore body. For example, when the ore body thickness is 8m, the cutting groove depth is 8m, and when the ore body thickness is 15m, it is 15m.

[0042] Specifically, the width of the cutting groove is 5m. Through the staged blasting of medium-long holes, a stable and continuous vertical free surface is formed, providing sufficient space conditions for subsequent fan-shaped medium-long hole blasting. The design of the cutting groove depth is 8-15m, combined with the dynamic adjustment of the ore body thickness, to ensure that the ore completely collapses to the ore body floor during the blasting process, reducing the amount of residual ore. The combination of fixed width and variable depth not only ensures blasting efficiency, but also adapts to different ore body thickness scenarios and reduces construction complexity. For example, when the ore body thickness is 10m, the cutting groove depth is set to 10m, which not only meets the ore recovery needs, but also avoids excessive disturbance of the surrounding rock and reduces the amount of support engineering.

[0043] Therefore, depth parameter control enables the vertical free surface of subsequent fan-shaped medium- and long-hole blasting operations to completely cover the vertical section of the ore body, avoiding the occurrence of unexploded ore residues or over-range blasting. By accurately matching the cutting groove depth with the ore body thickness, the spacing between the fan-shaped medium- and long-hole arrangements and the calculation of the charge amount have a clear spatial reference, thereby achieving precise blasting of the ore body boundary.

[0044] In some embodiments, reference Figure 2 During the cutting groove construction, 10 rows of medium-deep holes are arranged, with 3 holes arranged in each row, and the row surface inclination angles of the medium-deep holes from the 1st row to the 10th row decreases successively, and the maximum hole depths of the medium-deep holes from the 1st row to the 10th row decreases successively, wherein the row surface inclination angle of the medium-deep holes in the 1st row is 18°, and the maximum hole depth is 29m, the row surface inclination angle of the medium-deep holes in the 10th row is -23°, and the maximum hole depth is 14m; the 10 rows of medium-deep holes are blasted three times, the first blast is for the 1st to 3rd rows of medium-deep holes, the second blast is for the 5th to 6th rows of medium-deep holes, and the third blast is for the 7th to 10th rows of medium-deep holes.

[0045] Specifically, during the process of lowering the base plate while cutting uphill, 10 rows of medium-deep holes were detonated in stages according to their spatial positions. When rows 1-3 were first detonated, the deep holes with a maximum depth of 29 meters formed the initial fracture surface at a large inclination angle. When rows 5-6 were detonated in the middle section, the blasting energy with a moderate hole depth and inclination further expanded the fracture range. Finally, when rows 7-10 were detonated, shallow holes with a depth of 14 meters completed the final shattering of the base plate at a negative angle. The cumulative effect of the three blasting steps not only ensured the effective transfer of blasting energy, but also prevented excessive vibration from a single blast, which could lead to instability in the roadway. By precisely controlling the number of holes in each row, the row spacing, and the detonation sequence, the precise shaping of the cutting groove profile was achieved, improving construction efficiency.

[0046] During the trenching process, 10 rows of medium-long holes were laid out, with three holes per row. These rows were blasted in batches. Specifically, the medium-long holes were laid out in the lower level drift, using a drilling rig. The diameter of the medium-long holes was 89 mm, and the hole depth was determined by the thickness of the ore body. The spacing between each row of medium-long holes was 1.5 m, and the row spacing was 1.8 m. The blasting sequence was row by row, from top to bottom, with 2-3 rows of medium-long holes blasted each time. Non-electric millisecond delay detonators were used for blasting, and powdered emulsion explosives were used for the charge, with a continuous charge structure. After blasting, a scraper was used to transport the blasted ore out of the trench. This process was repeated until the bottom of the trench reached the ore body floor.

[0047] This embodiment effectively controls the quality of the cut groove. By blasting multiple rows of medium- and long holes in batches, the cut groove space can be gradually expanded, providing a better free surface for subsequent blasting. Furthermore, by rationally arranging the location and parameters of the medium- and long holes, the width and depth of the cut groove can be ensured to meet design requirements, creating favorable conditions for subsequent mining operations. Furthermore, batch blasting can reduce the amount of explosives used in a single blast, minimize disturbance to the surrounding rock mass, and improve mining safety.

[0048] In some embodiments, reference Figure 3 Each row of fan-shaped medium-deep holes is arranged with 12 holes in the vertical direction, and blasting is carried out with the cutting groove as the vertical free surface. Two rows of fan-shaped medium-deep holes are blasted each time, with a hole bottom distance of 2 to 2.5m and a row spacing of 2 to 2.5m. Each row of holes is 303.8m long and the charge is 750kg.

[0049] It can be understood that when the cutting groove is used as a vertical free surface for blasting, the blasting operation is carried out using fan-shaped medium-deep holes arranged in the vertical direction. Among them, the number of holes arranged in the vertical direction for each row of fan-shaped medium-deep holes is 12, which ensures that the blasting energy evenly covers the vertical free surface formed by the cutting groove, while avoiding incomplete ore crushing due to too few holes. The setting of 2 rows of fan-shaped medium-deep holes for each blasting can balance the blasting efficiency and safety control, and reduce the impact of the vibration generated by a single blasting on the mining site support structure. The vertical hole arrangement forms a spatial match with the geometric shape of the cutting groove, so that the blasting stress wave is effectively transmitted along the vertical free surface, thereby improving the ore crushing efficiency.

[0050] Specifically, after the cutting groove is formed, 12 holes arranged in a vertical direction are used to form a single row of fan-shaped medium-deep holes based on the vertical free surface. The charge amount of each hole is dynamically adjusted according to the physical properties of the ore body and the hole depth. For each blast, two adjacent rows of medium-deep holes are selected for simultaneous detonation. The charge structure of the two rows of holes adopts an interval micro-difference detonation method. The crushing zone formed after the detonation of the front row of holes provides a supplementary free surface for the rear row of holes, thereby reducing the blasting resistance. This method makes the ore crushing more uniform, reduces the proportion of large pieces of ore, and reduces the pyrotechnic consumption per unit of ore. In addition, the operation mode of blasting two rows at a time can shorten the overall blasting cycle of the stope, improve the continuous operation efficiency of the mining equipment, and avoid equipment loss caused by frequent start-up and shutdown.

[0051] The present invention combines dense vertical hole arrangement with double-row synchronous blasting to form a continuous crushing zone under vertical free surface conditions, effectively improving the uniformity of ore crushing, reducing the generation of large ore pieces, and at the same time reducing the number of rock drilling operations and the consumption of blasting equipment, thereby improving the recovery efficiency and safety of the triangular ore at the bottom of the mine room.

[0052] In a preferred embodiment, the arrangement surface inclination angle of the fan-shaped medium and deep holes is 90°. The design of the arrangement surface inclination angle of 90° keeps the fan-shaped medium and deep holes arrangement surface parallel to the vertical free surface formed by the cutting groove, ensuring that the blasting energy is evenly transmitted along the thickness direction of the ore body; the 12 holes arranged in the vertical direction form spatial coordination with the free surface of the cutting groove, so that the ore block size after blasting is more uniform.

[0053] Example 2 differs from Example 1 in that: in step 2, the cutting groove is constructed by drilling holes in the upper layer using a rock drill, and blasting is performed in stages to lower the cutting upper floor to form a cutting groove. The rock drill is installed in the upper layer tunnel, and drilling operations are carried out along the top plate of the ore body in the direction of the cutting upper floor. The inclination angle of the drilling axis and the floor matches the natural inclination of the ore body. The staged blasting adopts a multi-stage charging structure, and the depth of each blasting is controlled within the range of one-third to one-fifth of the total reduction of the cutting upper floor. By adjusting the charge and the detonation sequence, the floor is crushed and sunk in stages. The rock drill uses a YGZ90 rail-type drilling rig, the drilling diameter is set to 65-75 mm, and the drilling depth is dynamically adjusted according to the design height of the cutting groove. The interval time of the staged blasting is determined according to the rock crushing and settlement. After each blasting, a laser rangefinder is used to monitor the amount of bottom plate lowering.

[0054] Specifically, after the rock drill is fixed in the upper layer tunnel, an array of drill holes is arranged at intervals along the axis of the cutting uphill, with the hole spacing controlled at 0.8-1.2 meters. The first round of blasting charge is 70% of the hole depth, and an initial crushing zone is formed after detonation; the second round of blasting charge is increased to 85%, and the detonation time difference is set to 50 milliseconds to expand the crushing range; the last blasting uses full-hole depth charge to ensure that the bottom plate completely collapses. After each blasting, the rubble is removed through the air duct system, and the subsequent drilling angle is corrected in real time. This implementation method effectively controls the impact of blasting vibration on the tunnel support system by progressively destroying the rock structure in layers, while ensuring the accuracy of the cutting groove contour. The step-by-step charging design allows the energy of each blasting section to be concentrated on a specific rock layer, reducing the diffusion of ineffective energy and improving the utilization rate of explosives. The upper layer drilling operation avoids interference with the cross-construction of the lower layer tunnel and shortens the excavation cycle of the mining tunnel.

[0055] Through the above-mentioned embodiments, the present invention solves the problems of large support working surface spans and long construction periods in traditional manual shallow hole roof cutting processes. By combining mechanized drilling with staged blasting, workers are prevented from being exposed to unsupported, large-span roof areas, while also reducing the amount of anchor mesh support required. Staged blasting allows for precise control of the floor lowering process, ensuring both the quality of the cut groove and improved cutting efficiency, creating a stable vertical free surface for subsequent medium- to long-hole blasting.

[0056] Example 3, reference Figure 4-Figure 5 , the present invention provides a phosphate rock mining method:

[0057] 1. Based on the mining conditions of the ore body, the upward sub-level cemented filling mining method is selected;

[0058] 2. Applicable conditions: gently inclined ore bodies with poor surrounding rock stability require support;

[0059] 3. Stope structure parameters: The ore body is divided into several segments along the inclination within the mining area, and mined from the bottom up (i.e., upward mining). Each segment is mined in a backward arrangement along the strike direction. The vertical height of each segment (segment) is 8 to 25 meters, the inclined length is 30 to 45 meters, and the strike length of the ore block is 12 to 15 meters (the span of the mine room is reasonably determined based on the stability of the roof). During backfilling, the lower layer return air lane is retained as the upper layer transport lane, that is, the backfill of the lower layer is used as the floor of the upper layer transport lane. During the primary backfilling, a 3 to 5 meter bottom backfill isolation pillar (bottom pillar) is reserved at the bottom of the mine room. During the secondary backfilling, all the backfill is recovered and backfilled.

[0060] 4. Mining and Cutting: The panel ramps and segmented roadways are located within the A ore layer. Segmented roadways are laid along the A ore layer from the panel ramps and the return air uphill from the mining area to the end of the mining area. Then, a cutting uphill is constructed to connect the upper and lower segmented level roadways, and then the ore blocks are arranged for mining. Each ore block is equipped with a cutting uphill, which is excavated from top to bottom along the inclination of the ore layer roof. The cutting uphill is 5.0m x 4.0m (width x height). Anchor nets and anchor cables are used for support during excavation.

[0061] 5. Mining work:

[0062] ① Mining sequence: The mining sequence is upward in the inclination, that is, the lower section is mined first, and then the upper section is mined, and the mining sequence is backward in the strike direction.

[0063] ② Mining and filling: The ore body is divided into several blocks (stopes) along the strike within the segment, and they are numbered and managed in sequence in a backward manner. The order of the first batch of blocks mined and filled is 1, 3, 5..., and the order of the second batch of blocks mined and filled is 2, 4, 6... When the second batch of blocks is mined, the filling isolation pillars reserved at the bottom of the first batch of blocks are recovered, and the blocks are mined and filled in a backward cycle in an alternating manner in a skip mining (mining every other block). After the mining of the a ore layer is completed, filling is carried out immediately. After the filling body reaches a certain strength, the b ore layer can be mined.

[0064] After each block is cut and brought uphill, a 3-5m bottom-fill isolation pillar is reserved. The ore body on both sides of the cut and uphill is mined upwards (mining height ≤ 4m). Crawler scrapers push the ore to the stope's lower exit, where it is loaded onto trucks in the layered transport tunnels and transported to the mining area chute. After one cycle of ore is completed, false roof treatment and anchor net (cable) support are immediately implemented. This cycle continues upwards, mining the ore within the upper portion of the block (≤ 4m), completing the false roof treatment and anchor net (cable) support for the entire stope. Once the entire stope roof is supported, the ore at the bottom of the stope is mined all at once. Deep-hole blasting is then performed in the upper layered tunnels, completely mining the entire block (mining the isolation pillars at the bottom temporarily). All ore is then loaded onto trucks for transportation. The qualified ore size is ≤ 350mm, with some larger pieces undergoing secondary crushing in the stope.

[0065] ③ Rock drilling in the stope: Shallow hole top cutting is done using a YT-28 rock drill with a drill bit diameter of 38-42mm and a drill rod length of 2-5m. Medium-long hole mining is done using a medium-long hole drilling rig with a hole diameter of 76-102mm, a blasthole spacing of 2.0m, and a hole bottom distance of 2.0-2.4m.

[0066] ④ Ore dropping in the mining area: Emulsion explosives are used, and the explosives are loaded by charging trolleys. Manual charging is used in some areas, and non-electric tube or digital electronic detonator detonation system is used for detonation.

[0067] ⑤ Stope ventilation: After each blast, the stope must be fully ventilated and loose rocks on the roof must be cleared before personnel can enter. Air is drawn in through the sub-level tunnels and flows to the mining face. The dirty air is discharged through the upper sub-level tunnels.

[0068] ⑥ Transportation in the mining area: After ventilation is completed, the ore will be pried off and the unstable parts will be supported. The collapsed ore will be directly shoveled and unloaded into the mining truck by a scraper and transported to the nearest chute underground.

[0069] 6. Mining site support: After the top is cut, the top of the entire goaf is supported by anchor nets.

[0070] 7. Filling: After the mining of the mine chamber is completed, the goaf is filled with high-strength cementation, and the filling strength is greater than 2MPa.

[0071] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A phosphate mining method, characterized in that: The following steps are involved: Step 1: Cut uphill along the ore body roof from the lower layered level tunnel to the upper layered level tunnel, and use resin anchor rods and mining anchor cables for support; Step 2, cutting groove construction, arranging medium-deep holes in the lower layered level tunnel, loading explosives in the medium-deep holes and blasting them layer by layer, so that the cutting uphill bottom plate is continuously lowered until the ore body bottom plate, forming the cutting groove; Step 3, constructing fan-shaped medium-long holes in the lower layered level tunnel, wherein the fan-shaped medium-long holes are arranged in multiple rows in the vertical direction, and each row of the fan-shaped medium-long holes has multiple holes arranged in the vertical direction, and blasting is performed with the cutting groove as the vertical free surface, and the fan-shaped medium-long holes are blasted in batches; Step 4: Charge the lower layered tunnel with explosives, and use a remote-controlled forklift to enter the stope and mine after blasting.

2. A phosphate mining method according to claim 1, characterized in that: The width of the cutting groove is 5m, and the depth of the cutting groove is 8-15m.

3. A phosphate mining method according to claim 2, characterized in that: The depth of the cutting groove is equal to the thickness of the ore body.

4. The phosphate mining method according to claim 1, characterized in that: During the construction of the cutting groove, 10 rows of medium-deep holes are arranged, with 3 holes arranged in each row, and the 10 rows of medium-deep holes are blasted in batches.

5. A phosphate mining method according to claim 4, characterized in that: The row surface inclination angles of the medium-depth holes in the 1st to 10th rows decrease successively, and the maximum hole depths of the medium-depth holes in the 1st to 10th rows decrease successively.

6. A phosphate mining method according to claim 5, characterized in that: in, The inclination angle of the arrangement surface of the medium-deep holes in the first row is 18°, and the maximum hole depth is 29m. The inclination angle of the arrangement surface of the medium-deep holes in the tenth row is -23°, and the maximum hole depth is 14m.

7. A phosphate mining method according to claim 6, characterized in that: The 10 rows of medium-depth holes are blasted three times, the first blast is for the 1st to 3rd rows of medium-depth holes, the second blast is for the 5th to 6th rows of medium-depth holes, and the third blast is for the 7th to 10th rows of medium-depth holes.

8. The phosphate mining method according to claim 1, characterized in that: Each row of the fan-shaped medium-deep holes has 12 holes arranged in the vertical direction, and blasting is performed with the cutting groove as the vertical free surface, with 2 rows of the fan-shaped medium-deep holes blasted each time.

9. A phosphate mining method according to claim 8, characterized in that: The inclination angle of the arrangement surface of the fan-shaped deep holes is 90°.

10. The phosphate mining method according to claim 1, characterized in that: In step 2, the cutting groove is constructed by drilling holes in layers on the upper part with a rock drill, and blasting is performed in stages to lower the bottom plate of the cutting upper part to form the cutting groove.

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