A mining method of micro-inclined thin ore body deep hole sub-blasting and mining

Abstract

The application discloses a kind of mining methods of micro-inclined thin ore body deep hole sub-explosion with mining and filling, it is related to metal mine underground mining technical field, it is suitable for inclination ≤9 °, thickness ≤5m, roof surrounding rock medium and below stable, occurrence stable underground metal ore body, comprising the following steps: step S1, stope division and in-pulse mining preparation;Step S2, one-time through deep hole construction;Step S3, sub-explosive and hole isolation setting;Step S4, retreating blasting ore;Step S5, compressed air hole cleaning, gauge inspection and failure hole processing;Step S6, erect filling mold bag and dynamic ore pass;Step S7, mold bag filling;Step S8, adjacent ore block coordinated operation.The application realizes deep hole one-time construction, sub-retreating blasting and mining and filling with mining and filling of quasi-parallel operation, substantially reduces rock drilling auxiliary time, timely supports roof, reduces ore loss and dilution, improves the overall ore block ore removal capacity.

Description

Technical Field

[0001] This invention relates to the field of underground mining technology for metal mines, specifically to a mining method for deep-hole blasting and subsequent filling of a slightly inclined thin ore body. Background Technology

[0002] Slightly dipping thin ore bodies are a common type of ore body in underground metal mines. These ore bodies are generally characterized by a small dip angle, thin thickness, poor stability of the roof surrounding rock, and relatively stable occurrence, making them technically challenging to mine. Currently, the main mining methods for this type of ore body are open-pit mining, conventional backfilling mining, and deep-hole mining, but each of these mining techniques has significant shortcomings.

[0003] When using the open-cut mining method, a large number of permanent pillars and inter-pillars need to be reserved to maintain the stability of the stope roof, resulting in a high ore loss rate and a serious waste of mineral resources. At the same time, under thin ore body conditions, blast holes are very easy to penetrate the hanging wall and footwall, making it difficult to control the ore dilution index.

[0004] While conventional backfilling mining can reduce ore loss and achieve efficient resource recovery, it mostly adopts an external development layout, resulting in a large amount of mining and tunneling work. Traditional backfilling mining generally adopts a sequential mining and backfilling operation mode of "backfilling after overall mining is completed", which has a long mining and backfilling cycle, long exposure time of the roof in the goaf, high pressure control pressure, and limited overall ore extraction capacity of the block.

[0005] Deep-hole mining technology has the advantages of concentrated drilling and high ore extraction capacity in the stope. However, most existing deep-hole mining technologies are applied to medium-thick and thick ore bodies. When applied to thin ore bodies, blast holes need to be re-drilled for each mining cycle, resulting in many auxiliary drilling operations. After blasting, the blast holes are easily blocked and damaged by blasting debris, and the remaining blast holes cannot be reused, making it difficult to achieve segmented retreat mining. It also has poor adaptability to slightly inclined thin ore bodies. Summary of the Invention

[0006] The purpose of this invention is to provide a mining method for deep-hole blasting and charging in a slightly inclined thin ore body. While maintaining the principle of one-time construction of deep holes, each deep hole is divided into multiple charging sections according to the mining sequence. The blasting is carried out in reverse order from the ore outlet uphill side as the initial free direction towards the drilling uphill direction. At the same time, the remaining unblasted hole sections are cleaned, the diameter is checked, the holes are swept, and the failed holes are repaired. Flexible mold bags, wooden retaining walls, and dynamic ore outlet uphill are used to complete the charging and charging in sequence.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a mining method for slightly inclined thin ore bodies using deep-hole staged blasting with simultaneous mining and filling, applicable to underground metallic ore bodies with dip angle ≤9°, thickness ≤5m, moderately stable or less stable roof surrounding rock, and stable occurrence, comprising the following steps: Step S1, Stope Division and In-Vein Preparation: In the ore body, arrange the mid-section transport roadway along the strike and the in-vein transport ramp along the dip to divide the ore body into blocks. The blocks are 50m to 100m long and the thickness is the same as the ore body thickness. 3m to 5m pillars are set between the blocks. Drilling ramps and ore extraction ramps are set along the dip of the ore body next to the pillars of the blocks. The ore extraction ramps also serve as the initial compensation space, ore extraction passage, charging passage, and filling pipeline laying passage. Step S2, One-time deep hole construction: Multiple deep holes are constructed at once from the rock drilling uphill along the ore body bedding plane and parallel to the ore body strike, to the ore extraction uphill. The depth of the deep hole is equal to the net distance between the rock drilling uphill and the ore extraction uphill along the ore body strike. All deep holes are constructed before the mining blasting and are not repeated with each mining cycle. Step S3, phased charging and in-hole isolation setup: Taking the ore-exiting uphill side as the initial free surface, each deep hole is divided into several charging sections for sequential mining along the hole depth; a single mining cycle only charges the current charging section closest to the current free surface, and an in-hole isolation section and a plugging section are set between the current charging section and the uncharged hole sections to be blasted, and the remaining hole sections to be blasted are not pre-filled with explosives; Step S4, Retreating blasting for ore extraction: In the charge section of the detonation, based on the stability of the surrounding rock of the roof, a 3m to 5m wide ore body is caving down in a single blast. After the blasting is completed, ventilation and smoke removal are carried out, and a roof safety inspection is conducted. If necessary, roof support operations are implemented, and then the caving ore extraction operation is carried out, so that the mining face retreats from the ore extraction uphill direction to the rock drilling uphill direction. Step S5, Compressed Air Hole Cleaning, Drainage Inspection, and Failed Hole Treatment: After ore extraction, compressed air is used to clean the remaining blasting holes from the rock drilling uphill side; a connected hole cleaning drill rod and its front end drainage inspection head are used to test the patency of the blasting holes; low-load hole cleaning is performed on the local obstruction points of the blasting holes; for failed holes that cannot be restored to use after cleaning, the charge amount of adjacent blast holes is adjusted or compensation holes are added. Step S6, setting up filling mold bags and dynamic ore extraction channels: Starting from the second mining cycle, filling mold bags are set up in the formed goaf area; the length of the filling mold bag is the slant length of the ore block, the width is the blasting width of the previous cycle, and the height is equal to the thickness of the ore body; a wooden retaining wall is set up on the side of the filling mold bag facing the ore body, and a dynamic ore extraction ramp is reserved between the wooden retaining wall and the ore body, which serves as the passage for the ore extraction equipment in the next cycle; Step S7, Filling the formwork bag: A filling pipeline is installed in the upper middle part of the middle section of the formwork bag. The quick-setting early strength agent solution and cement tailings binder slurry are mixed evenly in the mixing tank at the end of the filling pipeline and then pumped into the filling formwork bag. After the filling body reaches the compressive strength required for mining, the steps S3 to S6 are repeated to carry out the next mining cycle. After all mining units are mined, the ore block outlet is sealed to complete the final filling of the stope. Step S8, Coordinated Operations of Adjacent Mining Blocks: When this mining block is carrying out mold bag filling or filling body curing operations, adjacent mining blocks can carry out ore extraction, hole cleaning inspection or charge preparation operations in parallel; when any unit carries out blasting operations, all personnel operations within the blasting warning range shall be stopped.

[0008] Furthermore, in step S2, before the deep hole construction, the number of rows, hole spacing and orientation of the deep holes are determined according to the boundaries of the upper and lower walls of the ore body, the true thickness of the ore body, the allowable value of the borehole deviation and the blasting influence range, so that the axis of the deep hole and its designed blasting boundary are located within the boundaries of the upper and lower walls of the ore body or within the allowable dilution control boundary. After all the deep hole construction is completed, the borehole coordinates, azimuth, dip angle, hole depth and breakthrough position are inspected and accepted, and a borehole record corresponding to each charge section in step S3 is generated. The term "one-time construction" refers to completing all designed deep holes before the current mining unit begins its blasting operations, rather than reconstructing the next cycle of deep holes after each blast.

[0009] Furthermore, in step S3, the current charge section is set at one end of the hole section to be detonated, close to the current free face. The length of the current charge section is determined based on the ore body thickness, the allowable exposure range of the roof, the minimum resistance line, the hole spacing, and the maximum allowable single charge amount.

[0010] Further, in step S3, the in-hole isolation section includes a guide sleeve coaxial with the deep hole, two elastic sealing rings spaced axially and pressed against the hole wall, a plugging spring, and a pull-out central plug and a central channel; the plugging spring is used to apply axial clamping force to the central plug to ensure that the central channel is sealed before blasting; before blasting, the central plug is pressed into the central channel, and after blasting, the central plug is pulled out by the rock drilling uphill side using a connecting hole cleaning drill rod, and then compressed air is used to remove rock powder. After the caliper is inspected and found to be qualified, the next cycle charging pipe passes through the central channel through the in-hole isolation section; The position, blocking length, and material of the elastic sealing ring are determined based on the borehole diameter, single-stage charge amount, and test blasting results.

[0011] Furthermore, in step S4, the roof safety inspection process includes roof support: in areas of moderately stable roof, anchor bolts or anchor mesh are used for local support; in areas where the roof stability is lower than moderately stable but can meet the requirements for short-term exposure after support, one or more combinations of anchor bolts, anchor mesh, anchor cables, steel strips, and temporary pillars are used for support, while shortening the single blasting advance length and controlling the exposure range of the goaf through timely filling; When detonating the current charge section, detonation is carried out sequentially or row by row from the current free face toward the ore body with a delay. By controlling the charge structure of the boundary holes, the amount of charge per shot, and the inter-hole delay, the disturbance of the blasting to the surrounding rocks of the ore body and the holes to be detonated is reduced.

[0012] Furthermore, in step S5, the compressed air cleaning includes: introducing compressed air from the rock drilling uphill side into the section of the hole to be blasted, and checking whether continuous air outlet and slag discharge are formed at the end of the blast hole on the current mining face side; The borehole inspection includes: feeding the connected cleaning drill rod into the section to be detonated at low speed and low propulsion force, and judging the unobstructed state based on the feed length, propulsion resistance and rotation resistance of the drill rod; the outer diameter of the borehole inspection head is smaller than the design diameter of the deep hole but larger than the minimum diameter required for the subsequent charging tube and detonating equipment to pass through; when the borehole inspection head reaches the design position of the next charging section, no continuous abnormal resistance occurs during the feeding process and the borehole can vent air normally, it is determined that the section to be detonated meets the charging requirements for the next cycle.

[0013] Furthermore, in step S5, when the section of the hole to be detonated becomes partially blocked, first maintain a low rotation speed and introduce compressed air to clean it, and then sweep the hole along the original hole axis with a low load. Let N be the total number of deep holes designed, nf be the number of failed holes, and the failure rate r = nf / N × 100%. When r ≤ 5%, the equivalent charge amount of the failed holes is allocated to adjacent intact holes according to the inverse weighting of distance; when 5% < r ≤ 15%, a compensation hole is added between the failed hole and the nearest intact hole, at a distance of 0.4 to 0.6 times the original hole distance from the failed hole and away from the ore body boundary; when r > 15% or there are 3 consecutive failed holes, blasting in that section is suspended and the holes are re-laid. The equivalent charge Qf corresponding to the failed hole is distributed to m adjacent intact holes according to the inverse distance weight. The increased charge ΔQi of the i-th adjacent intact hole is η×Qf×(1 / di) / Σ(1 / dj), where di is the distance from the i-th adjacent intact hole to the failed hole, and η is 0.8~1.0. The increase in charge of a single adjacent intact hole shall not exceed 15% of the original design value, and the increase in charge of a boundary hole shall not exceed 10%, and shall not exceed the design charge per hole. The remaining equivalent charge that cannot be allocated shall be borne by the compensation hole.

[0014] Furthermore, in step S6, the filling mold bag is made of a flexible filter material that allows the water exuded from the filling slurry to pass through and traps solid particles. The top of the filling mold bag is connected to the top plate support member through a hanging member, and the bottom is connected to the bottom plate or the existing filling body through an anchoring member. The mold bag is provided with a filling port, an air vent, and a filter outlet. The wooden retaining wall includes uprights arranged along the top and bottom plate direction and horizontal braces connecting adjacent uprights, which are used to limit the lateral expansion of the filling mold bag in the dynamic ore extraction and uphill direction, and to provide auxiliary constraints when the mold bag is partially damaged; The net width B of the dynamic ore extraction uphill meets the condition B≥W+2C, where W is the maximum working width of the ore extraction equipment and C is the safety clearance required on one side of the ore extraction equipment; the net height of the dynamic ore extraction uphill is determined based on the maximum working height of the ore extraction equipment, the height occupied by the roof support components, and the top safety clearance. The effluent discharged from the filling bag flows into the mining area collection ditch via drainage ditches and return pipes located on the lower side of the existing filling body or temporary passage.

[0015] Further, in step S7, the quick-setting early-strength agent is a compound of aluminum sulfate-based alkali-free liquid quick-setting agent and calcium formate early-strength component; based on cement mass, the dosage of aluminum sulfate-based alkali-free liquid quick-setting agent is 3%~5%, and the dosage of calcium formate is 0.5%~1.5%; the two components are first prepared into a pumpable solution or uniform suspension, and then pumped to the end of the filling pipeline by metering pump to mix with cement tailings binder slurry; The criterion for determining whether the filling material reaches the strength required for the next cycle is that the compressive strength of the standard specimen of the filling slurry with the same mix ratio is not less than 1.5 MPa.

[0016] Furthermore, when the ore body is vertically divided into upper and lower multi-level mining areas, the lower mining area is mined and filled first; after the lower filling body reaches the bearing capacity, the upper mining area is then mined.

[0017] The technical effects and advantages provided by the present invention in the above technical solution are as follows: 1. The entire deep-hole construction is completed in one go before mining, and subsequent mining cycles do not require repeated drilling. Only the charging section near the free face is charged, and the remaining blast holes are protected by the isolation section inside the hole, so that the same blast hole can be blasted in multiple stages. This greatly reduces the time spent on auxiliary operations such as drilling and blast hole positioning in each mining cycle and improves the efficiency of drilling operations. 2. Operational safety is controllable. A unified warning system is implemented for blasting operations. Personnel operations are suspended within the warning zone, while non-blasting procedures for other ore blocks can be carried out in parallel. Filling bags are used to isolate the filling slurry and prevent it from entering the ore body. Filling water is collected and channeled into a drainage ditch to improve the working environment in the mining area. 3. Excellent roof pressure control effect. After each blasting cycle, the formwork is immediately filled to support the roof of the stope in a timely manner, reducing the exposed area and exposure time of the goaf. The single blasting advance step can be dynamically adjusted according to the condition of the surrounding rock of the roof. Combined with support methods such as anchor bolts, anchor mesh, and anchor cables, it is suitable for medium and lower stable ore body conditions of the roof, reducing the safety risk of roof collapse. 4. It changes the traditional "mining and then filling" serial operation mode and realizes parallel operation of mining and filling at the same time; after the blasting is completed, the mold bag is filled immediately, and the rapid setting and early strength components are compounded on site at the end of the pipeline. When the filling body reaches 1.5MPa, the next round of mining can be carried out, which greatly shortens the mining and filling cycle time; at the same time, during the filling and curing of this block, adjacent blocks can carry out ore extraction, hole cleaning and charge preparation, and the staggered and coordinated operation between blocks significantly improves the overall ore extraction capacity of the block; 5. All preparation works are arranged inside the ore body, and the drilling and ore extraction uphill can be reused for multiple functions, eliminating the need for independent cutting uphill, dedicated charging roadways, and dedicated filling connecting roads. By-product ore is produced during tunneling, reducing the amount of mining and cutting work and tunneling costs; there is no need to leave a large number of permanent pillars, which significantly reduces ore loss; the layout of blast holes is controlled within the ore body boundary, effectively controlling mining dilution. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0019] Figure 1 This is a schematic diagram of the mining area layout according to the present invention.

[0020] Figure 2 This is a schematic diagram of the cross-section of the micro-inclined thin ore body along the dip direction according to the present invention.

[0021] Figure 3 This is a schematic cross-sectional view of the mining area according to the present invention.

[0022] Figure 4 This is a schematic diagram of the retreat mining cycle after the multi-stage blasting of the present invention.

[0023] Figure 5 This is a schematic diagram of the filling process for the molded bag according to the present invention.

[0024] Figure 6 This is a schematic diagram of the filling process of the present invention.

[0025] Figure 7 The following is a detailed diagram of the in-hole isolation section and the multi-stage charging structure of the present invention, wherein (a) is the state before blasting, and (b) is the state after blasting when the hole is cleaned and the next cycle of charging is carried out.

[0026] Explanation of reference numerals in the attached figures: 1. Slightly inclined thin ore body; 2. Hanging wall; 3. Footing wall; 4. Drilling uphill; 5. Ore extraction uphill; 6. Mid-level vein transport roadway; 7. Loading level roadway; 8. Deep borehole along strike; 9. Initial compensation space; 10. Current charging section; 11. In-hole isolation section; 12. Interstitial pillar; 13. Top pillar; 14. Anchor bolt; 15. Collapsed ore; 16. Reserved reinforcing bar; 17. Filling body; 18. Filling mold bag; 19. Wooden retaining wall; 20. Ore extraction equipment; 21. Dynamic ore extraction uphill; 22. Filling pipe; 23. Filter drainage outlet; 24. Hanging anchor bolt; 25. Bottom anchoring component; 26. Guide sleeve; 27. Elastic sealing ring; 28. Core plug spring; 29. ​​Central core plug; 30. Central channel. Detailed Implementation

[0027] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0028] The embodiments of the present invention will now be described with reference to the accompanying drawings. The parameters listed are used to illustrate the relationship between the various processes and do not constitute a limitation on the specific design parameters of the mine. Before formal engineering application, a special design should be completed based on the ore body occurrence conditions, roof rock mass quality, blasting tests, filling material tests, and equipment dimensions.

[0029] Taking a slightly inclined thin ore body with a dip angle of about 6° and an average thickness of about 3.2m as an example, mining units are divided along the strike of the ore body. The distance between the drilling uphill 4 and the ore extraction uphill 5 along the strike is 50m. The mid-section vein transport roadway 6 and the loading horizontal roadway are arranged along the strike of the ore body and are connected to the two uphills.

[0030] The cross-sections of the drilling uphill section 4 and the ore extraction uphill section 5 are determined according to the operating dimensions of the drilling equipment. The ore extraction uphill section 5 also serves as the initial compensation space 9. The roof is supported by anchor bolts 14 and local anchor mesh. The length of the anchor bolts 14 can be 2.0m~2.5m, and the row spacing can be 0.8m~1.0m. After blasting, temporary support is added according to the inspection results. The specifications and row spacing of the anchor bolts 14 and anchor mesh can be determined by the mine based on the on-site roof rock mass quality test.

[0031] Using down-the-hole drilling equipment, 76mm diameter deep holes (8) are drilled along the ore body surface towards the ore outlet (5) from the drilling uphill (4). The average hole depth is 50m, the hole spacing along the ore body dip is 0.80m, the hole depth deviation is no greater than 0.30m, the hole mouth deviation is no greater than 0.10m, and the penetration end deviation is no greater than 0.40m. Each deep hole is divided into 16 charging sections along the hole depth. Except for the last section, the length of each charging section is 3.0m. Continuous charging with 32mm diameter emulsion explosive cartridges is used, with a linear charge density of 1.15kg / m. The stemming section (31) is 0.80m long, the in-hole isolation section is 0.60m long, the inter-hole delay is 25ms, and the single-shot charge is no greater than 18kg. For boundary holes, the blasting disturbance to the ore body's hanging wall and footwall, as well as the section to be blasted, can be reduced by lowering the linear charge density and adjusting the inter-hole delay.

[0032] During the first mining operation, the section closest to the ore-exit incline 5 is designated as the charging section 10 for this operation. Subsequently, a plugging section, an in-hole isolation section, and a pre-blasting section are sequentially installed. No explosives are loaded into the pre-blasting section. The charging section length is set at 2.5m as the initial test value. When local roof joints and fissures are well-developed, but short-term exposure requirements can still be met after support, the length of the charging section can be appropriately reduced, and anchor mesh, anchor cables, steel strips, or temporary supports can be added after blasting.

[0033] In-hole isolation section according to Figure 7 The guide sleeve 26 is made of impact-resistant engineering plastic tubing with an outer diameter of 50mm, an inner diameter of 42mm, and a length of 600mm. Two elastic sealing rings 27 with an outer diameter of 72mm and an axial spacing of 180mm are installed on its outer circumference. A plugging spring 28 is assembled inside the guide sleeve 26 to apply axial clamping force to the central plugging core 29, ensuring the sealing of the central channel 30 before blasting. A 120mm long stretchable central plugging core 29 is installed inside the central channel 30. During installation, the isolation component is first fitted onto the front end of the connecting push rod, which is then pushed to the design boundary from the rock-drilling uphill side. After clamping the elastic sealing rings 27, the push rod is withdrawn, and the arrangement of the current charging section 10 is completed.

[0034] In this embodiment, the guide sleeve 26 and the elastic sealing ring 27 are disposable components left inside the blast hole. After the blasting is completed, only the central plug core 29 can be pulled out by the hole cleaning drill rod for reuse, while the guide sleeve 26 and the elastic sealing ring 27 remain inside the blast hole.

[0035] After the 10th charge section is detonated, following ventilation and roughening processes, ore is extracted from the ore extraction uphill side 5. After extraction is completed, the current free face retreats approximately one charge section in the rock drilling uphill direction 4.

[0036] After ore extraction, compressed air is used to clean the remaining blasting sections from the four sides of the drilling uphill: compressed air is introduced into the blasting sections from the four sides of the drilling uphill, and the end of the blast hole is checked to see if continuous airflow and slag removal are achieved. Then, a connecting cleaning drill rod and its front-end gauge head (outer diameter can be 60mm, less than the deep hole design diameter of 76mm but greater than the minimum diameter required for subsequent charging pipe passage) are fed into the blasting section at a low speed (e.g., 100r / min~200r / min) and low thrust. The unobstructed state is judged based on the drill rod's feed length and resistance. When the gauge head reaches the design position for the next charging section, no continuous abnormal resistance occurs during feeding, and the blast hole can vent air normally, the blasting section is deemed to meet the requirements for the next charging cycle. For locally blocked areas in the blasting section, the low speed is maintained and compressed air is introduced for cleaning, followed by low-load sweeping along the original hole axis.

[0037] If two out of the 60 deep holes fail after drilling, the failure rate is r = 3.33%. Following the rule that r ≤ 5%, no additional compensation holes are drilled. Using the equivalent charge Qf corresponding to the two failed holes as a benchmark, two intact holes are selected on each side, and the charge is allocated according to ΔQi = η × Qf × (1 / di) / Σ(1 / dj), where η is 0.90. The increment per adjacent intact hole is controlled within 10% of the original design charge, maintaining a maximum charge limit of 18 kg per hole. If the calculated increment exceeds the upper limit, the excess is borne by a compensation hole located 0.40~0.48 m away from the failed hole and furthest from the ore body boundary.

[0038] If the proportion of failed holes is in the range of 5% < r ≤ 15% under the conditions of this example, the amount of explosive charge should not be increased excessively in the adjacent intact holes. Instead, a compensation hole should be added between the failed hole and the nearest intact hole to accommodate the missing equivalent amount of explosive charge. If the proportion of failed holes is greater than 15% or three consecutive failed blast holes appear, the blasting operation in that section should be stopped, and the blast hole layout design and rock drilling should be carried out again.

[0039] Starting from the second cycle, filling formwork bags 18 are installed in the mined space. The top is connected to the hanging anchor bolts 24 via hanging components, and the bottom is fixed by the bottom anchoring components 25. Horizontal anchor bolts 14 are installed inside the formwork bag, with one end embedded in the surrounding rock and the other end pre-reserved with reinforcing bars 16 to support the next filling of the formwork bag, effectively enhancing the strength of the filling body. Wooden retaining walls 19 are arranged on the side of the formwork bag facing the ore body, with drainage outlets 23 to drain the drainage water from the filling. The dimensions of the wooden retaining wall columns and cross braces are verified based on the maximum lateral force of the formwork bag.

[0040] Assuming the maximum working width W of the selected ore extraction equipment is 1.8m and the single-sided safety clearance C is 0.6m, then the net width B of the dynamic ore extraction uphill section 21 should satisfy B≥3.0m. If more space is needed for equipment turning, bucket swinging, or personnel avoidance, the passage width should be increased according to the equipment operating envelope. This example is only used to illustrate the method of determining the passage width.

[0041] A filling pipeline 22 is installed in the upper-middle section of the upper section. Before filling, a solution mixing tank is set up in the upper section to dissolve aluminum sulfate-based alkali-free liquid quick-setting agent and calcium formate in water according to the specified ratio, preparing a uniform pumpable solution or suspension. The filling slurry is pumped into the filling mold bag 18 after being uniformly mixed with the above-mentioned quick-setting agent solution and cement tailings binder slurry before the mold bag inlet through the slurry mixing tank at the end of the filling pipeline 22. The tailings binder slurry has a mass concentration of 72%, and the mass ratio of cement to dry tailings is 1:6. The dosage of aluminum sulfate-based alkali-free liquid quick-setting agent is 4.0% of the cement mass, and the dosage of calcium formate is 1.0%. Exudate enters the drainage ditch through the filter outlet 23. During the filling process, the deformation of the mold bag, the hanging and bottom anchoring status, the displacement of the wooden retaining wall, and the drainage status are checked. After the filling pressure reaches 1.5 MPa, remove the temporary hole end protection component corresponding to the next charging position, conduct another compressed air penetration check, and then charge the next charging section.

[0042] The process of charging explosives, blasting, ventilation, ore extraction, hole cleaning and inspection, and filling of formwork bags was repeated in sequence to make the mining face retreat from the ore extraction uphill 5 to the rock drilling uphill 4.

[0043] When this ore block is in the backfilling and curing process, if conditions permit, ore extraction, hole cleaning or explosive loading preparation can be carried out on adjacent ore blocks in the horizontal direction; when any mining unit carries out blasting operations, all personnel within the blasting warning area shall be evacuated and all operations shall be stopped.

[0044] If the ore body has multiple layers in the vertical direction and it is necessary to divide it into upper and lower mining areas, the lower mining area should be completed first. Once the strength and integrity of the lower filling body meet the mining bearing conditions of the upper mining area, the upper mining area can then carry out the preparation, deep hole construction and mining blasting operations to avoid the lower unconsolidated filling body from being disturbed and destabilized by the upper mining.

[0045] After the mining is completed, all passages in the mining area are sealed and the final backfilling is completed.

[0046] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for mining slightly inclined thin ore bodies using deep-hole staged blasting with simultaneous mining and charging, applicable to underground metallic ore bodies with dip angle ≤9°, thickness ≤5m, moderately stable roof surrounding rock, and stable occurrence, characterized in that... Includes the following steps: Step S1, Stope Division and In-Vein Preparation: In the ore body, arrange the mid-section transport roadway along the strike and the in-vein transport ramp along the dip to divide the ore body into blocks. The blocks are 50m to 100m long and the thickness is the same as the ore body thickness. 3m to 5m pillars are set between the blocks. Drilling ramps and ore extraction ramps are set along the dip of the ore body next to the pillars of the blocks. The ore extraction ramps also serve as the initial compensation space, ore extraction passage, charging passage, and filling pipeline laying passage. Step S2, One-time deep hole construction: Multiple deep holes are constructed at once from the rock drilling uphill along the ore body bedding plane and parallel to the ore body strike, to the ore extraction uphill. The depth of the deep hole is equal to the net distance between the rock drilling uphill and the ore extraction uphill along the ore body strike. All deep holes are constructed before the mining blasting and are not repeated with each mining cycle. Step S3, phased charging and in-hole isolation setup: Taking the ore-exiting uphill side as the initial free surface, each deep hole is divided into several charging sections for sequential mining along the hole depth; a single mining cycle only charges the current charging section closest to the current free surface, and an in-hole isolation section and a plugging section are set between the current charging section and the uncharged hole sections to be blasted, and the remaining hole sections to be blasted are not pre-filled with explosives; Step S4, Retreating blasting for ore extraction: In the charge section of the detonation, based on the stability of the surrounding rock of the roof, a 3m to 5m wide ore body is caving down in a single blast. After the blasting is completed, ventilation and smoke removal are carried out, and a roof safety inspection is conducted. If necessary, roof support operations are implemented, and then the caving ore extraction operation is carried out, so that the mining face retreats from the ore extraction uphill direction to the rock drilling uphill direction. Step S5, Compressed Air Hole Cleaning, Drainage Inspection, and Failed Hole Treatment: After ore extraction, compressed air is used to clean the remaining blasting holes from the rock drilling uphill side; a connected hole cleaning drill rod and its front end drainage inspection head are used to test the patency of the blasting holes; low-load hole cleaning is performed on the local obstruction points of the blasting holes; for failed holes that cannot be restored to use after cleaning, the charge amount of adjacent blast holes is adjusted or compensation holes are added. Step S6, setting up filling mold bags and dynamic ore extraction channels: Starting from the second mining cycle, filling mold bags are set up in the formed goaf area; the length of the filling mold bag is the slant length of the ore block, the width is the blasting width of the previous cycle, and the height is equal to the thickness of the ore body; a wooden retaining wall is set up on the side of the filling mold bag facing the ore body, and a dynamic ore extraction ramp is reserved between the wooden retaining wall and the ore body, which serves as the passage for the ore extraction equipment in the next cycle; Step S7, Filling the formwork bag: A filling pipeline is installed in the upper middle part of the middle section of the formwork bag. The quick-setting early strength agent solution and cement tailings binder slurry are mixed evenly in the mixing tank at the end of the filling pipeline and then pumped into the filling formwork bag. After the filling body reaches the compressive strength required for mining, the steps S3 to S6 are repeated to carry out the next mining cycle. After all mining units are mined, the ore block outlet is sealed to complete the final filling of the stope. Step S8, Coordinated Operations of Adjacent Mining Blocks: When this mining block is carrying out mold bag filling or filling body curing operations, adjacent mining blocks can carry out ore extraction, hole cleaning inspection or charge preparation operations in parallel; when any unit carries out blasting operations, all personnel operations within the blasting warning range shall be stopped.

2. The mining method for deep-hole multi-stage blasting and simultaneous filling of a slightly inclined thin ore body according to claim 1, characterized in that: In step S2, before the deep hole construction, the number of rows, hole spacing and orientation of the deep holes are determined according to the boundaries of the upper and lower walls of the ore body, the true thickness of the ore body, the allowable value of the borehole deviation and the blasting influence range, so that the axis of the deep hole and its designed blasting boundary are located within the boundaries of the upper and lower walls of the ore body or within the allowable dilution control boundary. After all the deep hole construction is completed, the borehole coordinates, azimuth, dip angle, hole depth and breakthrough position are inspected and accepted, and a borehole record corresponding to each charge section in step S3 is generated. The term "one-time construction" refers to completing all designed deep holes before the current mining unit begins its blasting operations, rather than reconstructing the next cycle of deep holes after each blast.

3. The mining method for deep-hole multi-stage blasting and simultaneous filling of a slightly inclined thin ore body according to claim 1, characterized in that: In step S3, the current charge section is set at one end of the blast hole section near the current free face. The length of the current charge section is determined based on the ore body thickness, the allowable exposure range of the roof, the minimum resistance line, the borehole spacing, and the maximum allowable single charge amount.

4. The mining method for deep-hole multi-stage blasting and simultaneous filling of a slightly inclined thin ore body according to claim 1, characterized in that: In step S3, the in-hole isolation section includes a guide sleeve coaxial with the deep hole, two elastic sealing rings spaced axially and pressed against the hole wall, a plugging spring, and a pull-out central plug and a central channel. The plugging spring is used to apply axial clamping force to the central plug to ensure that the central channel is sealed before blasting. Before blasting, the central plug is pressed into the central channel. After blasting, the central plug is pulled out by the rock drilling uphill side using a connecting hole cleaning drill rod. Then, compressed air is used to remove rock powder. After the caliper is checked and found to be qualified, the next cycle charging pipe passes through the central channel through the in-hole isolation section. The position, blocking length, and material of the elastic sealing ring are determined based on the borehole diameter, single-stage charge amount, and test blasting results.

5. The mining method for deep-hole multi-stage blasting and simultaneous filling of a slightly inclined thin ore body according to claim 1, characterized in that: In step S4, the roof safety inspection process includes roof support: in areas of moderately stable roof, anchor bolts or anchor mesh are used for local support; in areas where the roof stability is lower than moderately stable but can meet the requirements for short-term exposure after support, one or more combinations of anchor bolts, anchor mesh, anchor cables, steel strips, and temporary pillars are used for support, while shortening the single blasting advance length and controlling the exposure range of the goaf by timely filling. When detonating the current charge section, detonation is carried out sequentially or row by row from the current free face toward the ore body with a delay. By controlling the charge structure of the boundary holes, the amount of charge per shot, and the inter-hole delay, the disturbance of the blasting to the surrounding rocks of the ore body and the holes to be detonated is reduced.

6. The mining method for deep-hole multi-stage blasting and simultaneous filling of a slightly inclined thin ore body according to claim 1, characterized in that: In step S5, the compressed air cleaning includes: introducing compressed air from the rock drilling uphill side into the section of the hole to be blasted, and checking whether continuous air outlet and slag discharge are formed at the end of the blast hole on the current mining face side; The borehole inspection includes: feeding the connected cleaning drill rod into the section to be detonated at low speed and low propulsion force, and judging the unobstructed state based on the feed length, propulsion resistance and rotation resistance of the drill rod; the outer diameter of the borehole inspection head is smaller than the design diameter of the deep hole but larger than the minimum diameter required for the subsequent charging tube and detonating equipment to pass through; when the borehole inspection head reaches the design position of the next charging section, no continuous abnormal resistance occurs during the feeding process and the borehole can vent air normally, it is determined that the section to be detonated meets the charging requirements for the next cycle.

7. The mining method for deep-hole multi-stage blasting and simultaneous filling of a slightly inclined thin ore body according to claim 1, characterized in that: In step S5, when the section of the hole to be detonated becomes partially blocked, first maintain a low rotation speed and introduce compressed air to clean it, and then sweep the hole along the original hole axis with a low load. Let N be the total number of deep holes designed, nf be the number of failed holes, and the failure rate r = nf / N × 100%. When r ≤ 5%, the equivalent charge amount of the failed holes is allocated to adjacent intact holes according to the inverse weighting of distance; when 5% < r ≤ 15%, a compensation hole is added between the failed hole and the nearest intact hole, at a distance of 0.4 to 0.6 times the original hole distance from the failed hole and away from the ore body boundary; when r > 15% or there are 3 consecutive failed holes, blasting in that section is suspended and the holes are re-laid. The equivalent charge Qf corresponding to the failed hole is distributed to m adjacent intact holes according to the inverse distance weight. The increased charge ΔQi of the i-th adjacent intact hole is η×Qf×(1 / di) / Σ(1 / dj), where di is the distance from the i-th adjacent intact hole to the failed hole, and η is 0.8~1.

0. The increase in charge of a single adjacent intact hole shall not exceed 15% of the original design value, and the increase in charge of a boundary hole shall not exceed 10%, and shall not exceed the design charge per hole. The remaining equivalent charge that cannot be allocated shall be borne by the compensation hole.

8. The mining method for deep-hole multi-stage blasting and simultaneous filling of a slightly inclined thin ore body according to claim 1, characterized in that: In step S6, the filling mold bag is made of a flexible filter material that allows water from the filling slurry to pass through and traps solid particles. The top of the filling mold bag is connected to the top plate support member through a hanging member, and the bottom is connected to the bottom plate or the existing filling body through an anchoring member. The mold bag is provided with a filling port, an air vent, and a filter outlet. The wooden retaining wall includes uprights arranged along the top and bottom plate direction and horizontal braces connecting adjacent uprights, which are used to limit the lateral expansion of the filling mold bag in the dynamic ore extraction and uphill direction, and to provide auxiliary constraints when the mold bag is partially damaged; The net width B of the dynamic ore extraction uphill meets the condition B≥W+2C, where W is the maximum working width of the ore extraction equipment and C is the safety clearance required on one side of the ore extraction equipment; the net height of the dynamic ore extraction uphill is determined based on the maximum working height of the ore extraction equipment, the height occupied by the roof support components, and the top safety clearance. The effluent discharged from the filling bag flows into the mining area collection ditch via drainage ditches and return pipes located on the lower side of the existing filling body or temporary passage.

9. The mining method for deep-hole multi-stage blasting and simultaneous filling of a slightly inclined thin ore body according to claim 1, characterized in that: In step S7, the quick-setting early-strength agent is a compound of aluminum sulfate-based alkali-free liquid quick-setting agent and calcium formate early-strength component; based on cement mass, the dosage of aluminum sulfate-based alkali-free liquid quick-setting agent is 3%~5%, and the dosage of calcium formate is 0.5%~1.5%; the two components are first prepared into a pumpable solution or uniform suspension, and then pumped to the end of the filling pipeline by metering pump to mix with cement tailings binder slurry; The criterion for determining whether the filling material reaches the strength required for the next cycle is that the compressive strength of the standard specimen of the filling slurry with the same mix ratio is not less than 1.5 MPa.

10. The mining method for deep-hole multi-stage blasting and simultaneous filling of a slightly inclined thin ore body according to claim 1, characterized in that: When the ore body is divided into upper and lower multi-level mining areas in the vertical direction, the lower mining area is mined and backfilled first; after the backfill of the lower mining area reaches the bearing conditions required for the mining of the upper mining area, the mining operation of the upper mining area is carried out.

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