Method for preventing and treating underground debris flow and dilution by in-situ consolidation modification of moraine

Abstract

The application provides a method for preventing and treating underground debris flow and dilution by in-situ consolidation modification of moraine, and belongs to the technical field of metal mine disaster prevention and treatment. The method first flattens and compacts the site of the grouting consolidation area to be injected; then grouting is performed on the shallow part of the grouting layer, and after maintenance, grouting is continuously performed on the deep part, and finally the hole depth reaches the bedrock surface; during the subsequent ore drawing process, the underground ore drawing opening corresponding to the grouting consolidation area is observed, the form, block size and quantity of the moraine consolidation body are recorded, and sampling is performed for strength testing; according to the law of the moraine consolidation body and the occurrence state of the overburden layer, the safety grade of the moraine area is determined, the underground ore drawing safety area is divided, and then the ore drawing plan and ore drawing system suitable for different safety grade ore drawing areas are formulated, so as to reduce the underground debris flow disaster and reduce the loss and dilution of the ore. The method can reduce the loss and dilution of mining and selection, and has important application value for the safety and economy of metal mine exploitation.

Description

Technical Field

[0001] This invention relates to the field of metal mine disaster prevention and control technology, and in particular to a method for preventing debris flows and depletion in mines through in-situ consolidation and modification of glacial till. Background Technology

[0002] Natural caving in metal ore mining is a relatively economical underground mining method with high production capacity and low mining costs. However, the most important drawback is that the mining process causes surface subsidence. Surface precipitation creates a large catchment area in the subsidence zone, leading to the mudification of glacial deposits. During underground ore discharge, as the pore channels develop, underground debris flows are highly likely to occur, causing varying degrees of casualties and equipment damage. Moreover, as mining progresses, the subsidence area expands, the amount of mud increases, and the hazards intensify. Furthermore, it causes losses in ore beneficiation, as glacial deposits mix with the ore and cannot be removed, resulting in a sharp decline in beneficiation recovery rates. It also causes mining losses, as the caving ore blocks are large and porous, while the glacial deposits are small and preferentially move downwards, forming flow channels that reach the ore outlet prematurely, causing the ore grade to rapidly drop to the cutoff grade, resulting in ore loss and dilution.

[0003] This invention addresses the prevention and control of debris flows and ore dilution in underground mines by carrying out in-situ consolidation and modification of glacial till. It utilizes grouting technology to consolidate the glacial till into blocks, cutting off the source conditions for the formation of debris flows underground at the source. Furthermore, it establishes a uniform ore discharge system to achieve uniform subsidence of the glacial till overburden layer, reducing ore loss and dilution. This invention has significant practical implications for the safe, economical, and efficient mining of metal mines. Summary of the Invention

[0004] This invention provides a method for preventing debris flows and depletion in wells through in-situ consolidation and modification of glacial deposits, mainly targeting the natural collapse method.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] A method for preventing debris flows and depletion in underground mines through in-situ consolidation and modification of glacial deposits includes the following steps:

[0007] S1. Level and compact the site in the grouting consolidation area;

[0008] S2. Grouting of the shallow grout-stopping layer: grouting holes are spaced 1m apart. Drilling is carried out using an XY-150 drilling rig, and a borehole pipe is placed. The drilling depth is 2m. The borehole sealing grouting method is used, proceeding from the outside to the inside. To prevent cross-grouting, the principle of skipping holes in two sequences is adopted, first sequence I holes and then sequence II holes. After grouting is completed, mechanical grouting sealing method is used to seal the holes and then curing is carried out.

[0009] S3. For deep grouting in sections, the deep grouting holes are selected at intervals in step S2 to ensure that the interval between adjacent deep grouting holes is 2m. The drilling is carried out in one go using an XY-150 drilling rig. The grouting is carried out in sections from top to bottom as required, with a section height of 5m. The grouting construction method is adopted from the outer perimeter to the inner perimeter. After the grouting is completed, the hole is sealed by mechanical grouting and cured. Then the drilling and grouting operation of the next section is carried out. Finally, the hole depth reaches the bedrock surface.

[0010] S4. During the subsequent ore discharge process, observe the underground ore discharge port corresponding to the grouting consolidation area, record the shape, size and quantity of the glacial till solidified body, and take samples for strength testing;

[0011] S5. Based on the pattern of the solidified glacial deposits released in step S4 and the occurrence state of the overburden, the SEP risk assessment method is used to determine the safety level of the grouting consolidation area, which is divided into 5 safety levels:

[0012] Low risk, corresponding to unexploited areas;

[0013] Low to medium risk, corresponding to the mining boundary;

[0014] Medium risk, corresponding to unmined areas within the mining area;

[0015] Medium to high risk, corresponding to scattered mining areas within the mining scope;

[0016] High risk, corresponding to concentrated ore-draining areas within the mining area;

[0017] Based on the above safety levels, the underground mining safety zones are divided as follows: the mining operation area boundary that has not formed a surface collapse and water catchment area is designated as a safe zone; the scattered mining area that is located on the slope of the collapse zone is designated as a general zone; and the concentrated mining area that is located in the collapse center area covered by water catchment is designated as a high-risk zone.

[0018] S6. Based on the underground ore-discharge safety zones defined in step S5, formulate an ore-discharge control plan applicable to ore-discharge zones with different safety levels:

[0019] For safe zones, implement an ore production plan that is 1.5 to 2 times the average daily ore production.

[0020] For general areas, ore discharge should be carried out at 1 to 1.5 times the average daily ore output.

[0021] For high-risk areas, ore discharge shall be carried out at 0 to 0.5 times the average daily ore output.

[0022] The mining process utilizes unmanned equipment to reduce the need for personnel to enter the mining area.

[0023] The ore outlets corresponding to the above-mentioned ore-discharging areas all adopt an equal and uniform sequential ore-discharging system.

[0024] In step S2, the borehole diameter is 130mm, the borehole position deviation shall not exceed ±10cm, the deposition thickness inside the borehole shall not exceed 20cm, the borehole opening diameter is 110mm, the depth is 80cm, the borehole opening is fixed by concrete pouring, and the borehole diameter below the borehole opening is 90mm.

[0025] The grouting pressure of the grout-stopping layer in step S2 is 0.5-5 MPa; the grouting material injection amount is 100 kg / m, and the grout-stopping layer is cured for at least 7 days after grouting.

[0026] In step S3, the borehole diameter is 90 mm, the grouting pressure is 0.5-5 MPa, the grouting material injection volume is 200 kg / m, and the deep section grouting is completed and cured for at least 28 days.

[0027] In step S4, before the ore is released, after the deep grouting curing is completed, a trench 4m deep, 2m wide and 6m long is dug in the shallow part of each grouting area for observation and sampling analysis. Drilling is also carried out around the deep grouting holes in the grouting area to collect samples. The samples are brought back to the laboratory for consolidation performance testing.

[0028] The consolidation performance test specifically involves testing the diffusion radius, compressive strength, disintegration resistance, and water resistance of the in-situ grouting consolidation body. The strength of the glacial till consolidation body must reach 1 MPa or higher. If it cannot reach 1 MPa, the grout ratio is adjusted until the strength of the consolidation body reaches 1 MPa.

[0029] The above technical solution has at least the following advantages compared with the existing technology:

[0030] The aforementioned scheme utilizes grouting to consolidate and modify in-situ glacial till, solidifying it into blocks. This transforms the till from "powder" to "blocks" and from "small" to "large," effectively preventing underground debris flows and ore loss and dilution caused by the till overburden layer. Grouting effectively blocks the source conditions for underground debris flows and allows for uniform ore discharge, ensuring mine safety. Furthermore, the till, appearing as larger blocks during discharge and settling evenly with the collapsing ore, is easily separated from the ore, significantly reducing ore loss and dilution. The till breaks into blocks during uniform discharge, no longer mixed with the ore as mud, reducing beneficiation difficulty and costs. In-situ consolidation and modification of glacial till is of great significance for safe, economical, and efficient mine mining. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of grouting of the glacial till cover layer and control of the migration of the consolidation layer in a method for preventing debris flow and depletion in wells by in-situ consolidation modification of glacial till in this invention.

[0033] Figure 2 This is a schematic diagram of the grouting hole distribution in the in-situ grouting construction scheme of the method for preventing debris flow and depletion in wells using natural collapse method by in-situ consolidation modification of glacial till in this invention.

[0034] Figure 3 This is a cross-sectional view of the shallow and deep hole grouting process in the in-situ grouting construction scheme of the method for preventing debris flow and depletion in wells using natural collapse method by in-situ consolidation modification of glacial deposits according to the present invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] As is well known, natural caving is an efficient and economical mining method, but it can cause surface subsidence. Moreover, due to the presence of glacial till overburden above the ore deposit, fine-grained glacial till can flow through pores during rainfall, causing mudslides in the mine, resulting in casualties, equipment damage, and ore loss and dilution, which seriously affects the normal mining operations of metal mines.

[0037] To address this, the present invention provides a method for preventing and controlling debris flows and ore depletion in mines through in-situ consolidation and modification of glacial till. By grouting the glacial till overburden layer, the glacial till is consolidated and modified, thereby blocking the conditions for debris flows from the source and controlling the migration of the consolidated glacial till, reducing ore loss and depletion, and ensuring safe, economical, and efficient mining of metal mines.

[0038] The method includes the following steps:

[0039] S1. Level and compact the site in the grouting consolidation area;

[0040] S2. Grouting of the shallow grout-stopping layer: grouting holes are spaced 1m apart. Drilling is carried out using an XY-150 drilling rig, and a borehole pipe is placed. The drilling depth is 2m. The borehole sealing grouting method is used, proceeding from the outside to the inside. To prevent cross-grouting, the principle of skipping holes in two sequences is adopted, first sequence I holes and then sequence II holes. After grouting is completed, mechanical grouting sealing method is used to seal the holes and then curing is carried out.

[0041] S3. For deep grouting in sections, the deep grouting holes are selected at intervals in step S2 to ensure that the interval between adjacent deep grouting holes is 2m. The drilling is carried out in one go using an XY-150 drilling rig. The grouting is carried out in sections from top to bottom as required, with a section height of 5m. The grouting construction method is adopted from the outer perimeter to the inner perimeter. After the grouting is completed, the hole is sealed by mechanical grouting and cured. Then the drilling and grouting operation of the next section is carried out. Finally, the hole depth reaches the bedrock surface.

[0042] S4. During the subsequent ore discharge process, observe the underground ore discharge port corresponding to the grouting consolidation area, record the shape, size and quantity of the glacial till solidified body, and take samples for strength testing;

[0043] S5. Based on the pattern of the solidified glacial deposits released in step S4 and the occurrence state of the overburden, the SEP risk assessment method is used to determine the safety level of the grouting consolidation area, which is divided into 5 safety levels:

[0044] Low risk, corresponding to unexploited areas;

[0045] Low to medium risk, corresponding to the mining boundary;

[0046] Medium risk, corresponding to unmined areas within the mining area;

[0047] Medium to high risk, corresponding to scattered mining areas within the mining scope;

[0048] High-risk areas correspond to concentrated ore-discharging areas within the mining scope;

[0049] Based on the above safety levels, the underground mining safety zones are divided as follows: the mining operation area boundary that has not formed a surface collapse and water catchment area is designated as a safe zone; the scattered mining area that is located on the slope of the collapse zone is designated as a general zone; and the concentrated mining area that is located in the collapse center area covered by water catchment is designated as a high-risk zone.

[0050] S6. Based on the underground ore-discharge safety zones defined in step S5, formulate an ore-discharge plan applicable to ore-discharge zones with different safety levels to control the ore-discharge volume:

[0051] For safe zones, implement an ore production plan that is 1.5 to 2 times the average daily ore production.

[0052] For general areas, ore discharge should be carried out at 1 to 1.5 times the average daily ore output.

[0053] For high-risk areas, ore discharge shall be carried out at 0 to 0.5 times the average daily ore output.

[0054] The mining process utilizes unmanned equipment to reduce the need for personnel to enter the mining area.

[0055] The ore outlets corresponding to the above-mentioned ore-discharging areas all adopt an equal and uniform sequential ore-discharging system.

[0056] The method of the present invention is arranged as follows Figure 1 As shown, in the specific implementation process, the arrangement of grouting holes in the glacial till and the shallow grouting layer and deep grouting procedures are as follows: Figure 2 and Figure 3 As shown, the ore layer formed by the natural caving method is in the lower part, and the ore is discharged through the ore discharge funnel. The upper part is a glacial till overburden layer. The glacial till overburden layer is constructed by constructing a shallow grout-stopping layer, grouting and consolidating it in deep sections, and implementing a uniform ore discharge system in sequence. This achieves the consolidation of the glacial till into blocks. At the same time, the uniform ore discharge system controls the movement of the consolidated glacial till layer, thereby reducing the risk of debris flow during underground ore discharge and reducing ore loss and dilution.

[0057] The specific implementation process is as follows:

[0058] S1: Before grouting and consolidation, the site needs to be leveled and compacted.

[0059] S2: Shallow grout stop layer grouting. Grouting holes are arranged in 1m×1m patterns and drilled using an XY-150 drilling rig. The hole diameter is 130mm, and the hole position deviation must not exceed ±10cm, and the deposition thickness inside the hole must not exceed 20cm. A borehole pipe with a diameter of 110mm and a depth of 80cm is placed and fixed with concrete. Then, a 90mm diameter hole is drilled downwards along the borehole pipe to a depth of 2m. The borehole sealing grouting method is used, proceeding from the outside to the inside. To prevent grout cross-contamination, a two-sequence skip-hole grouting principle is adopted, first for the first sequence holes and then for the second sequence holes. The grouting is divided into two areas: a cement grouting area and a chemical grouting area. The cement grout and chemical grout stop layer grouting is completed step by step, with a grouting pressure range of 0.5~5MPa. The grouting volume of both cement grout and chemical grout is 100 kg / m. After grouting, mechanical grouting is used to seal the holes and then cure them. The grout-stopping layer must be cured for at least 7 days before the subsequent deep hole grouting can be carried out.

[0060] S3: Deep segmented grouting. Drilling is carried out using an XY-150 drilling rig in one pass, with a borehole diameter of 90mm. Grouting holes are arranged in 2m×2m configurations. Grouting is carried out in segments from top to bottom, with a segment height of 5m and a grouting pressure range of 0.5~5MPa. The grouting method is adopted from the outer perimeter to the inner perimeter, with cement grout and chemical grout being injected separately. The injection volume of both cement grout and chemical grout is 200Kg / m. After grouting, mechanical grouting is used to seal the holes and cure them before proceeding to the next segment of drilling and grouting. The final hole depth is up to the bedrock surface. Deep segmented grouting must be cured for at least 28 days before subsequent work can be carried out.

[0061] S4: Effect verification. After the deep grouting curing is completed, a 4m deep, 2m wide and 6m long trench is dug in the shallow part of each grouting test area for observation and sampling analysis. Drilling and sampling are also carried out around the deep grouting holes in the test area. The samples are brought back to the laboratory for consolidation performance testing. The diffusion radius, compressive strength, disintegration resistance and water resistance of the in-situ grouting consolidation body are tested. The strength of the glacial till consolidation body should reach more than 1MPa. If it cannot reach 1MPa, the grout ratio is adjusted until the strength of the consolidation body reaches 1MPa.

[0062] S5: During the subsequent ore discharge process, observe the underground ore discharge port corresponding to the grouting consolidation area, record the shape, size and quantity of the glacial till solidified body, and take samples for strength testing to ensure that it meets the strength requirements in step S4.

[0063] S6: Based on the pattern of the released glacial till solidification and the occurrence state of the overburden, the SEP risk assessment method is used to determine the safety level of the grouting consolidation area, which is divided into 5 safety levels: low risk, low-medium risk, medium risk, medium-high risk, and high risk. Low risk corresponds to unmined areas, low-medium risk corresponds to the mining boundary, medium risk corresponds to unmined areas within the mining area, medium-high risk corresponds to small-scale ore-mining areas within the mining area, and high risk corresponds to concentrated ore-mining areas within the mining area. Based on the above risk levels, underground ore-mining safety zones are divided: ore-mining operation boundaries without surface subsidence or catchment areas are considered safe zones; small-scale ore-mining areas with relatively small subsidence areas are considered general zones; and large-scale concentrated ore-mining areas located in the subsidence center and with large catchment areas are considered high-risk zones.

[0064] S7: Based on the designated underground ore-discharging safety zones, formulate ore-discharging plans applicable to different safety levels. The average daily ore-discharging volume is 40,000 tons. For safe zones, a daily ore-discharging volume of 60,000 tons is implemented; for general zones, 40,000 tons are discharged; and for high-risk zones, 20,000 tons are discharged, using unmanned loaders, with no personnel entering the mining area. All ore-discharging outlets in the aforementioned zones adopt an equal-volume, uniform sequential ore-discharging system. Equal ore discharge ensures uniform settlement of the consolidated layer, preventing soil flow through the overburden layer, reducing the mixing of glacial deposits into the ore, and minimizing losses, dilution, and debris flow risks.

[0065] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preventing and controlling debris flow and dilution by in-situ consolidation modification of moraine, characterized in that, The steps include the following: S1. Level and compact the site in the grouting consolidation area; S2. Grouting of the shallow grout-stopping layer: grouting holes are spaced 1m apart. Drilling is carried out using an XY-150 drilling rig, and a borehole pipe is placed. The drilling depth is 2m. The borehole sealing grouting method is used, proceeding from the outside to the inside. To prevent cross-grouting, the principle of skipping holes in two sequences is adopted, first sequence I holes and then sequence II holes. After grouting is completed, mechanical grouting sealing method is used to seal the holes and then curing is carried out. S3. For deep grouting in sections, the deep grouting holes are selected at intervals in step S2 to ensure that the interval between adjacent deep grouting holes is 2m. The drilling is carried out in one go using an XY-150 drilling rig. The grouting is carried out in sections from top to bottom as required, with a section height of 5m. The grouting construction method is adopted from the outer perimeter to the inner perimeter. After the grouting is completed, the hole is sealed by mechanical grouting and cured. Then the drilling and grouting operation of the next section is carried out. Finally, the hole depth reaches the bedrock surface. S4. During the subsequent ore discharge process, observe the underground ore discharge port corresponding to the grouting consolidation area, record the shape, size and quantity of the glacial till solidified body, and take samples for strength testing; S5. Based on the pattern of the solidified glacial deposits released in step S4 and the occurrence state of the overburden, the SEP risk assessment method is used to determine the safety level of the grouting consolidation area, which is divided into 5 safety levels: Low risk, corresponding to the mining area; Low to medium risk, corresponding to the mining boundary; Medium risk, corresponding to unmined areas within the mining area; Medium to high risk, corresponding to scattered mining areas within the mining scope; High risk, corresponding to concentrated ore-draining areas within the mining area; Based on the above safety levels, the underground mining safety zones are divided as follows: the mining operation area boundary that has not formed a surface collapse and water catchment area is designated as a safe zone; the scattered mining area that is located on the slope of the collapse zone is designated as a general zone; and the concentrated mining area that is located in the collapse center area covered by water catchment is designated as a high-risk zone. S6. Based on the underground ore-discharge safety zones defined in step S5, formulate an ore-discharge plan applicable to ore-discharge zones with different safety levels to control the ore-discharge volume: For safe zones, implement an ore production plan that is 1.5 to 2 times the average daily ore production. For general areas, ore discharge should be carried out at 1 to 1.5 times the average daily ore output. For high-risk areas, ore discharge shall be carried out at 0 to 0.5 times the average daily ore output. Unmanned equipment is used for ore extraction; The ore outlets corresponding to the above-mentioned ore-discharging areas all adopt an equal and uniform sequential ore-discharging system.

2. The method for preventing debris flows and depletion in wells by in-situ consolidation and modification of glacial tillage as described in claim 1, characterized in that, In step S2, the borehole diameter is 130mm, the borehole position deviation shall not exceed ±10cm, the deposition thickness inside the borehole shall not exceed 20cm, the borehole opening diameter is 110mm, the depth is 80cm, the borehole opening is fixed by concrete pouring, and the borehole diameter below the borehole opening is 90mm.

3. The method for preventing debris flows and depletion in wells by in-situ consolidation and modification of glacial tillage as described in claim 1, characterized in that, In step S2, the grouting pressure of the grout stop layer is 0.5-5 MPa, the grouting material injection amount is 100 kg / m, and the grout stop layer is cured for at least 7 days after grouting.

4. The method for preventing debris flows and depletion in wells by in-situ consolidation and modification of glacial tillage according to claim 1, characterized in that, In step S3, the borehole diameter is 90 mm, the grouting pressure is 0.5-5 MPa, the grouting material injection volume is 200 kg / m, and the deep section grouting is completed and cured for at least 28 days.

5. The method for preventing debris flows and depletion in wells by in-situ consolidation and modification of glacial tillage according to claim 1, characterized in that, In step S4, before the ore is released, after the deep grouting curing is completed, a trench 4m deep, 2m wide and 6m long is dug in the shallow part of each grouting area for observation and sampling analysis. Drilling is also carried out around the deep grouting holes in the grouting area to collect samples. The samples are brought back to the laboratory for consolidation performance testing.

6. The method for preventing debris flows and depletion in wells by in-situ consolidation and modification of glacial tillage according to claim 5, characterized in that, The consolidation performance test specifically involves testing the diffusion radius, compressive strength, disintegration resistance, and water resistance of the in-situ grouting consolidation body. The strength of the glacial till consolidation body must reach 1 MPa or higher. If it cannot reach 1 MPa, the grout ratio is adjusted until the strength of the consolidation body reaches 1 MPa.

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