A downward parallel medium-length hole sublevel filling mining method for low-grade broken ore body

Abstract

The application provides a downward parallel medium-length hole segmented filling mining method for low-grade broken ore body, belongs to the technical field of mine exploitation, and solves the problems of low mining efficiency and high cost of traditional mining methods under complex geological conditions. The stope is divided into multiple segments along the vertical direction, downward parallel medium-length holes are used for rock drilling and blasting in each segment, remote control ore extraction and supporting equipment are used to realize efficient stoping, the goaf adopts interlayer filling process combined with a steel mesh structure to form an artificial false roof, the stress and displacement changes of the filling body are monitored in real time through a ground pressure monitoring system, and the stoping sequence and supporting parameters are optimized. The application solves the problems of efficiency and safety of traditional mining methods in the mining of low-grade, broken ore deposits and "three-under" resources, realizes large-scale, low-cost, safe and efficient mining, and is suitable for the mining of ore bodies under complex geological conditions.

Description

Technical Field

[0001] This invention belongs to the field of mining technology, specifically relating to a method for subdivided backfilling mining of low-grade fractured ore bodies using downward parallel medium-deep holes. Background Technology

[0002] In the field of metal mining, traditional mining methods face dual challenges of efficiency and safety for low-grade, fractured deposits and resources in areas requiring protection of important surface facilities (under buildings, water bodies, and major transportation routes). Taking Jinchuan Group as an example, its existing mines have entered the middle and late stages of mining, while the newly developed Area IV mine has typical characteristics of being in these three areas—not only is the grade low (0.47% nickel and 0.26% copper), but the engineering geology and hydrogeology of the deposit are also complex (fractured ore bodies, well-developed joints and fissures, and accompanying water seepage), but there are also key protected objects such as water conservancy facilities, major transportation routes, and optical cables distributed on the surface. The traditional mechanized panel-based downward layered horizontal approach cemented backfill mining method cannot meet the economic development needs of this type of resource due to its high mining cost and low efficiency.

[0003] Existing segmented backfill mining technology has revealed many shortcomings in practical applications: Complexity of stope structure and stress: Compared with the traditional layered method, the stope height of the segmented filling mining method is significantly increased (e.g., the segment height reached 8.6~9.8m in the experiment). The ore falling through medium and deep holes leads to a more complex stress state in the stope. The exposed area of ​​ore and rock on both sides is large, which makes it easy for side collapse to occur, and the support difficulty is significantly increased.

[0004] Limitations of blasting control technology: Traditional blasting parameters are difficult to adapt to the boundary control requirements of fractured ore bodies. After the segment height is increased, the protection effect of smooth blasting and buffer blasting technology on the sidewalls of the filling body and the sidewalls of the ore body needs to be further optimized in order to avoid damage to the filling body or excessive damage to the ore body caused by blasting.

[0005] Filling process and stability of false roof: When filling high goaf areas, the reliability of the connection of the steel mesh of the artificial false roof is reduced because the construction of the hanging rod is not possible. In addition, there is a lack of systematic research on the ratio parameters of key layers and ordinary layers, filling efficiency and roof connection effect in the interlayer filling structure, making it difficult to ensure the long-term stability of the false roof.

[0006] Ground pressure monitoring and safety assurance: During the segmented mining process, the dynamic changes in the stress, displacement, and reinforcement of the backfill are still unclear. Existing monitoring methods are unable to provide real-time feedback on the stability of the mining area, resulting in delayed risk warnings.

[0007] Patent CN110985114A proposes a mining method applicable to gold deposits with dip angles of 50-90° and horizontal thicknesses of 4-10m. The mining area described in the patent has complex ore and rock conditions, similar to the ore body targeted by the patent. Citing this patent allows for comparison with its techniques used in mining similar ore bodies, such as the construction of artificial roofs and floors and the selection of backfill materials. This highlights the research value of this experimental scheme in addressing different ore body conditions and optimizing mining processes, emphasizing its innovative significance in adapting to complex geological conditions and reducing costs.

[0008] To address the aforementioned problems, there is an urgent need to develop a segmented backfilling mining method suitable for low-grade, fractured deposits in the "three-level" (underground, underground, and deep-ground) geological conditions. This method aims to achieve safe, efficient, and low-cost mining by optimizing the stope structure, blasting process, support technology, and backfilling system. The downward parallel medium-deep hole segmented backfilling mining method proposed in this invention aims to overcome the application bottlenecks of traditional methods under complex geological conditions through the integration of technologies such as segmented mining, remote operation, interlayer backfilling, and real-time ground pressure monitoring. Summary of the Invention

[0009] The purpose of this invention is to provide a downward parallel medium-deep hole segmented backfilling mining method for low-grade fractured ore bodies, so as to solve the problems of low mining efficiency and high cost of traditional mining methods under complex geological conditions.

[0010] The technical solution of this invention is: a method for subdivided backfilling mining of low-grade fractured ore bodies using downward parallel medium-deep holes, comprising the following steps: S1. The method of segmented rock drilling, segmented ore extraction, and segmented backfilling is adopted. The bench approach mining method is used, and the downward horizontal approach backfilling method adopts a multi-layer simultaneous mining method from top to bottom. First, the ore body is divided into several segments along the vertical direction. Each segment includes a control top layer and a pull bottom layer. The control top layer is located above the pull bottom layer, forming a segmented mining structure. The stopes are arranged in the segments along the strike of the ore body. The segmented structure with adjustable segment height is adopted, and the sub-panels are divided for continuous mining. S2. Construct drilling connecting roadways, ore extraction connecting roadways, and drilling roadways within the segment to build a ventilation and ore extraction system; reach the stage transport roadway along the vein from the inclined ramp to the footwall of the stope, construct the segment transport horizontal roadway in the stage transport roadway, then construct the segment connecting roadway to reach the ore body, construct the drilling connecting roadway vertically from the segment connecting roadway to the ore body, and construct the ore pass downwards in the segment connecting roadway at the top of each stage to construct the stage connecting roadway. S3. At one end of the ore body, a backfilling air shaft is constructed from the stage connecting roadway at the top of the stage downwards along the height of the ore body. The backfilling air shaft runs through the entire stope. From the top of the backfilling air shaft, a backfilling air roadway is constructed towards the backfilling body of the upper stage stope. The backfilling air roadway is connected to the backfilling system of the upper stage stope. S4. Horizontal shallow-hole blasting is used to form a drilling tunnel in the top layer of the control layer, and downward parallel medium-deep holes are used for drilling in the bottom layer. Smooth blasting and buffer blasting techniques are used to control the sidewalls of the ore body and the sidewalls of the filling body. Under the protection of the artificial false roof, the upper layer is mined back using the approach method in the drilling connecting roadway to form a drilling roadway. At the end of the drilling roadway, the ore extraction connecting roadway is constructed. After checking the quality of the artificial false roof and strengthening the support of the two sides, a cutting groove is formed at the end of the stope. Downward parallel medium-deep holes are drilled in the drilling roadway, and ore is laterally caving towards the cutting groove. S5. The lateral collapse ore body is operated by a remote-controlled loader. After leaving the mining area, it is driven manually and unloaded into the ore pass through the rock drilling connecting roadway and the segment connecting roadway. It is then transported out through the stage connecting roadway. Steel fiber concrete support is implemented on both sides of the mining area by a remote-controlled shotcrete trolley. After all mining and backfilling of all mining areas in the panel are completed, it is lowered to the lower section. S6. After the mining is completed, a steel mesh is laid and an alternating layer filling process of key layer and ordinary layer is adopted to form an artificial false roof. At the same time, stress gauges and displacement gauges are arranged in the filling body and steel mesh to monitor the stability of the mining area in real time.

[0011] As a further improvement of the present invention, in step S1, the segmented mining sequence adopts continuous mining of sub-panel areas, and the curing time of the backfill body in adjacent mining areas is determined according to the strength test results to ensure the stability of the mining area.

[0012] As a further improvement of the present invention, in step S4, the medium-deep hole drilling blasting adopts smooth blasting technology for the sidewalls of the ore body and buffer blasting technology for the sidewalls of the filling body, and controls the blasting parameters to form regular boundaries.

[0013] As a further improvement of the present invention, in step S6, in the interlayer filling process, a high ash-sand ratio filling material is used in the key layer and a low ash-sand ratio filling material is used in the ordinary layer, and the thickness of the key layer is determined according to the stope height.

[0014] As a further improvement of the present invention, in step S6, the stability of the mining area is monitored by a vibrating wire sensor to monitor the stress of the filling body, the force on the reinforcing bars and the settlement of the filling body. The data is fed back in real time through a wireless transmission system and is used to adjust the mining and filling parameters.

[0015] The beneficial effects of this invention are as follows: 1. This invention combines segmented mining with medium-deep hole blasting, which increases the amount of ore produced per blast and reduces the amount of preparation work. Compared with the traditional access mining method, it significantly improves production efficiency.

[0016] 2. The present invention uses remote control equipment to reduce personnel entering dangerous areas, and interlayer filling and ground pressure monitoring ensure the stability of the mining area, thereby reducing the risk of roof collapse and sidewall spalling.

[0017] 3. This invention reduces material consumption and mining costs by optimizing the filling ratio and stope structure, and is suitable for mining low-grade ore deposits.

[0018] 4. This invention can dynamically adjust the segment height, blasting parameters and support scheme according to the geological conditions of the ore body, and is applicable to fractured ore deposits and mining of underground resources.

[0019] In summary, this invention solves the problems of low efficiency and high cost of traditional mining methods when mining under complex geological conditions, and realizes safe, efficient and low-cost large-scale mining. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the mining system I-I structure of the present invention; Figure 2 This is a schematic diagram of the mining system II-II structure of the present invention; Figure 3 This is a schematic diagram of the mining system III-III structure of the present invention; Figure 4 This is a schematic diagram of the segmented mining area division in Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the layout of blast holes in the top layer of the mining area in Embodiment 1 of the present invention; Figure 6 This is a side view schematic diagram of the arrangement of blast holes in the top layer of the mining area in Embodiment 1 of the present invention; Figure 7 This is a top view schematic diagram of the arrangement of blast holes in the top layer of the mining area control zone in Embodiment 1 of the present invention; Figure 8 This is a schematic diagram of controlled blasting in downward medium-deep hole drilling in Embodiment 1 of the present invention; Figure 9 This is a diagram of the mining area support scheme in Embodiment 1 of the present invention.

[0021] In the diagram: 1. Stage transport roadway; 2. Inclined ramp; 3. Segmented transport level roadway; 4. Stage connecting roadway; 5. Pass; 6. Filling return airway; 7. Filling return air shaft; 8. Segmented connecting roadway; 9. Ore extraction connecting roadway; 10. Rock drilling connecting roadway; 11. Rock drilling roadway; 12. Artificial false roof. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Example 1 S1. The method of segmented rock drilling, segmented ore extraction and segmented backfilling is adopted. The bench approach mining method is used. The downward horizontal approach backfilling method adopts a top-down double or multi-layer simultaneous mining method. First, the ore body is divided into several segments along the vertical direction. Each segment includes the control top layer and the pull bottom layer. The control top layer is located above the pull bottom layer, forming a segmented mining structure. like Figure 4 As shown, the stopes are arranged in sections along the strike of the ore body. The width of each stope is determined based on the thickness of the ore body, and the section height is adjusted to accommodate the drilling equipment and coordinate with adjacent stopes, ensuring that the subsequent access mining height meets the requirements. A section structure with adjustable section heights is adopted. Based on the stability of the ore body and the coordination needs of adjacent stopes, the section heights are flexibly adjusted, dividing the area into multiple sub-panels for continuous mining. The mining sequence follows the principle of edge-to-center mining to ensure that the backfill material meets strength requirements during curing. During continuous mining of sub-panels, the curing time of the backfill material in adjacent stopes is determined based on strength test results to ensure the overall stability of the stope.

[0024] S2. Construct drilling connecting roadway 10, ore extraction connecting roadway 9 and drilling roadway 11 within the segment to build a ventilation and ore extraction system; reach the stage transport roadway 1 along the vein from the inclined ramp 2 to the footwall of the stope, construct the segment transport level roadway 3 in the stage transport roadway 1, then construct the segment connecting roadway 8 to reach the ore body, construct drilling connecting roadway 10 vertically from the segment connecting roadway 8 to the ore body, and construct the ore pass 5 downward in the segment connecting roadway 8 at the top of each stage, and construct the stage connecting roadway 4.

[0025] S3. At one end of the ore body, a backfilling air shaft 7 is constructed from the stage connecting roadway 4 at the top of the stage downwards along the height of the ore body. The backfilling air shaft 7 runs through the entire stope. From the top of the backfilling air shaft 7, a backfilling air roadway 6 is constructed from the backfilling body of the upper stage stope. The backfilling air roadway 6 is connected to the backfilling system of the upper stage stope.

[0026] Steps S1-S3 are as follows: Figures 1-3 The mining preparation project is shown in the figure. The rock drilling connecting roadway 10 and the mine exit downhill are constructed according to the design. The cross-sectional specifications meet the requirements for equipment passage. The roadway is supported by shotcrete and anchor net to ensure stability. The ventilation system utilizes the existing ventilation shaft extension and forms an independent return air route through local fans and ventilation ducts.

[0027] S4. Horizontal shallow-hole blasting is used to form drilling roadway 11 in the top layer of the control layer. Downward parallel medium-deep holes are used for drilling in the bottom layer. Smooth blasting and buffer blasting techniques are used to control the sidewalls of the ore body and the sidewalls of the filling body. Under the protection of artificial false roof 12, the upper layer is mined in the drilling connecting roadway 10 using the approach method to form drilling roadway 11. At the end of drilling roadway 11, ore extraction connecting roadway 9 is constructed. After checking the quality of the artificial false roof 12 and strengthening the support of the two sides, a cutting groove is formed at the end of the stope. Downward parallel medium-deep holes are drilled in drilling roadway 11, and ore is laterally blasted in the direction of the cutting groove.

[0028] First, horizontal drilling rigs are used to drill blast holes, employing a wedge-cut blasting technique. Depending on whether the stope boundary is ore body or backfill, the distance between the borehole and the boundary is adjusted, and blasting parameters are controlled to minimize boundary damage. Down-the-hole (DTH) rigs are used to construct the blast holes, equipped with in-hole casing to prevent collapse. Smooth blasting is used to control the ore body edges, while buffer blasting protects the backfill edges. By optimizing the spacing between blast rows, hole spacing, and detonation sequence, the blasting effect is ensured while minimizing damage to subsequent blast holes. Smooth blasting is used for ore body edges, while buffer blasting is used for backfill edges, with controlled blasting parameters creating regular boundaries.

[0029] Step S4 is as follows Figures 5-7 The deep-hole drilling and blasting method shown is as follows: For the top layer control, horizontal holes are drilled using a drilling rig; for the bottom layer, downward-facing holes are drilled using a down-the-hole drill rig, with a diameter of 80mm. PVC casing is installed inside each hole to prevent collapse. The spacing between smooth blasting holes on the ore body sidewalls is 0.5m, with a linear charge density of 0.5kg / m³; the spacing between buffer blasting holes on the backfill sidewalls is 1.0m, with a linear charge density of 1.0kg / m³. Blasting employs millisecond-delayed detonation, with control holes detonated 50-100ms after the main blasting holes to reduce vibration impact.

[0030] S5. The ore body of the directional collapse is operated by a remote-controlled loader. After leaving the mining area, it is driven manually. It is unloaded into the ore pass 5 through the rock drilling connecting roadway 10 and the segment connecting roadway 8, and then transported out through the stage connecting roadway 4. The two sides of the mining area are supported by steel fiber concrete through a remote-controlled shotcrete trolley. After all mining and backfilling of the mining areas in the panel are completed, it is lowered to the lower section.

[0031] S6. After the mining is completed, a steel mesh is laid and an alternating layer filling process of key layer and ordinary layer is adopted to form an artificial false roof 12. At the same time, stress gauges and displacement gauges are arranged in the filling body and steel mesh to monitor the stability of the mining area in real time.

[0032] The bottom critical layer uses high-strength backfill material, i.e., a high-ash-sand ratio backfill material, and the thickness of the critical layer is determined according to the stope height. The upper ordinary layer uses economical backfill material, i.e., a low-ash-sand ratio backfill material. By combining different ash-sand ratios and mass concentrations, the amount of cement used is reduced while meeting strength requirements. Precast steel mesh or steel cages are laid and connected by hooks or lap joints to form an integral reinforced structure, improving the integrity of the backfill body. Secondly, according to the joint density of the rock in the control layer, shotcrete and anchor mesh support or steel fiber reinforced concrete support is used. The bottom layer is supported by a remote-controlled shotcrete trolley, and the support range and thickness are dynamically adjusted according to monitoring data.

[0033] like Figure 9The remote-controlled ore extraction and support are shown below: A remote-controlled loader is used to enter the stope from the ore extraction connecting roadway 9, while manual operation is conducted outside the stope. Support is provided by a remote-controlled shotcrete trolley spraying steel fiber reinforced concrete, with the anchor bolt arrangement adjusted according to joint development.

[0034] Stress gauges, displacement gauges, and rebar stress gauges are deployed in pressure-sensitive areas to construct a multi-parameter monitoring network, collecting real-time data on infill stress, settlement, and rebar stress. For pressure monitoring, vibrating wire sensors are used to monitor infill stress, rebar stress, and infill settlement. Monitoring data is transmitted wirelessly to the control system in real-time for dynamic adjustment of mining and filling parameters. Blasting parameters are optimized through blasting vibration monitoring, and an early warning mechanism is established based on monitoring data to guide adjustments in mining and filling procedures. Remote-controlled excavators and shotcrete trolleys are used to achieve unmanned operation in hazardous areas, improving construction safety.

[0035] This embodiment employs the following methods: Stope division: used to determine segment heights and stope specifications, and to plan the layout of the preparatory mining project; Rock drilling and blasting: including medium-deep hole drilling equipment and a blasting parameter control system, to achieve precise downward hole construction and blasting boundary control; Remote operation: including remote-controlled loaders, shotcrete trolleys, and control systems, to achieve unmanned ore extraction and support; Filling support: used for laying steel mesh, hanging filling pipes, and executing interlayer filling processes; Segmented filling: laying precast steel reinforcement structures; first pumping high-strength key layer slurry, then filling ordinary layers, and after curing, transferring to another layer for mining to verify the strength of the filling body; Ground pressure monitoring: composed of stress gauges, displacement gauges, and a data acquisition system, to monitor the stability of the stope in real time.

[0036] By optimizing segmented heights, dynamically adjusting blasting parameters, and employing interlayer backfilling technology, safe and efficient mining of the stope was achieved. Compared to traditional methods, production efficiency was increased by more than 30%, and backfilling costs were reduced by 20%, verifying the feasibility of this invention. Those skilled in the art can adjust specific parameters according to actual geological conditions, all of which fall within the scope of protection of this invention.

Claims

1. A method for subdivided backfilling mining of low-grade fractured ore bodies using downward parallel medium-deep holes, characterized in that: Includes the following steps: S1. The method of segmented rock drilling, segmented ore extraction, and segmented backfilling is adopted. The bench approach mining method is used, and the downward horizontal approach backfilling method adopts a multi-layer simultaneous mining method from top to bottom. First, the ore body is divided into several segments along the vertical direction. Each segment includes a control top layer and a pull bottom layer. The control top layer is located above the pull bottom layer, forming a segmented mining structure. The stopes are arranged in the segments along the strike of the ore body. The segmented structure with adjustable segment height is adopted, and the sub-panels are divided for continuous mining. S2. Construct drilling connecting roadways (10), ore extraction connecting roadways (9) and drilling roadways (11) within the segment to build a ventilation and ore extraction system; reach the stage transport roadway (1) along the vein from the ramp (2) to the footwall of the stope, construct the segment transport level roadway (3) in the stage transport roadway (1), and then construct the segment connecting roadway (8) to reach the ore body. Construct the drilling connecting roadway (10) vertically from the segment connecting roadway (8) to the ore body. In the segment connecting roadway (8) at the top of each stage, construct the chute (5) downwards and construct the stage connecting roadway (4). S3. At one end of the ore body, a backfilling air shaft (7) is constructed from the stage connecting roadway (4) at the top of the stage downwards along the height direction of the ore body. The backfilling air shaft (7) runs through the entire stope. From the top of the backfilling air shaft (7) to the backfilling body of the upper stage stope, a backfilling air roadway (6) is constructed. The backfilling air roadway (6) is connected to the backfilling system of the upper stage stope. S4. Horizontal shallow hole blasting is used to form a rock drilling tunnel in the top layer of the control layer, and downward parallel medium-deep hole drilling is used in the bottom layer. Smooth blasting and buffer blasting techniques are used to control the side walls of the ore body and the side walls of the filling body. Under the protection of the artificial false roof (12), the upper layer is mined in the rock drilling connecting roadway (10) by the approach method to form the rock drilling roadway (11). At the end of the rock drilling roadway (11), the ore extraction connecting roadway (9) is constructed. After checking the quality of the artificial false roof (12) and strengthening the support of the two sides, a cutting groove is formed at the end of the stope. Downward parallel medium-deep hole is drilled in the rock drilling roadway (11) and the ore is laterally collapsed in the direction of the cutting groove. S5. The lateral collapse ore body is operated by a remote-controlled loader. After leaving the mining area, it is driven manually. It is unloaded into the ore pass (5) through the rock drilling connecting roadway (10) and the segment connecting roadway (8), and then transported out through the stage connecting roadway (4). Steel fiber concrete support is implemented on both sides of the mining area by a remote-controlled shotcrete trolley. After all mining and filling of the mining area are completed, it is lowered to the lower section. S6. After the mining is completed, a steel mesh is laid and an alternating layer filling process of key layer and ordinary layer is adopted to form an artificial false roof (12). At the same time, stress gauges and displacement gauges are arranged in the filling body and steel mesh to monitor the stability of the mining area in real time.

2. The method for subdivided backfilling mining of low-grade fractured ore bodies using downward parallel medium-deep holes according to claim 1, characterized in that: In step S1, the segmented mining sequence adopts continuous mining of sub-panel areas, and the curing time of the backfill body in adjacent mining areas is determined according to the strength test results to ensure the stability of the mining area.

3. The method for subdivided backfilling mining of low-grade fractured ore bodies using downward parallel medium-deep holes according to claim 1, characterized in that: In step S4, the medium-deep hole drilling blasting uses smooth blasting technology for the ore body sidewalls and buffer blasting technology for the filling body sidewalls, controlling the blasting parameters to form regular boundaries.

4. The method for subdivided backfilling mining of low-grade fractured ore bodies using downward parallel medium-deep holes according to claim 1, characterized in that: In step S6, during the interlayer filling process, a high ash-sand ratio filling material is used in the critical layer, and a low ash-sand ratio filling material is used in the ordinary layer. The thickness of the critical layer is determined according to the stope height.

5. A method for subdivided backfilling mining of low-grade fractured ore bodies using downward parallel medium-deep holes according to claim 1, characterized in that: In step S6, the stability of the mining area is monitored by using a vibrating wire sensor to monitor the stress of the filling body, the stress on the reinforcing bars, and the settlement of the filling body. The data is fed back in real time through a wireless transmission system and is used to adjust the mining and filling parameters.

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