An old goaf CO 2 Mineralization Grouting Method

Abstract

The present invention discloses a method for CO2 mineralization grouting in old goafs, which belongs to the technical field of goaf treatment; it includes the following steps: First, divide the grouting range of the goaf into the caving zone and the fissure zone. Determine the slurry diffusion radius of the caving zone and the fissure zone under the condition of isobaric grouting through grouting in the experimental area. The caving zone and the fissure zone share the same borehole for grouting. Take the slurry diffusion radius of the caving zone as an index to design the borehole spacing for grouting and filling work, and carry out the filling of the caving zone and the fissure zone; then inject mineralization materials and industrial waste gas into the goaf. The injected mineralization material slurry can react with the industrial waste gas, while fixing the industrial waste gas, it supports the goaf. In the present invention, the industrial waste gas is injected into the goaf and reacts with the slurry and is sealed underground, effectively reducing environmental pollution, and the product generated after reacting with the slurry plays a role in supporting and protecting the goaf, which has a positive effect on environmental protection and treatment.

Description

Technical Field

[0001] The present invention belongs to the technical field of goaf treatment, and more specifically, relates to a CO 2 Mineralization grouting method. Background Art

[0002] In recent years, the grouting technology for old goaf has developed rapidly, and a variety of grouting methods have been gradually proposed, including: at a certain mining depth, the old goaf can be filled with strip grouting, and the spacing between grouting holes is twice the slurry diffusion radius; the grouting filling methods for the long wall gently inclined old goaf can be divided into three types: point column grouting, strip grouting and full grouting. However, the current grouting methods have the following deficiencies or disadvantages:

[0003] 1. The grouting diffusion radius of the collapse zone and the crack zone is considered equal, resulting in deviation in the design of the grouting hole spacing;

[0004] 2. The minimum diffusion radius of the collapse zone and the crack zone is used as an indicator to design the drilling hole spacing, resulting in too small a spacing of the grouting holes, which results in too many holes and too much drilling volume;

[0005] 3. The old goaf can be used as a reaction site for mineralized material slurry and industrial waste gas, but it has not been fully utilized. Summary of the invention

[0006] The present invention aims at solving the technical problems existing in the prior art and provides a CO 2 Mineralization grouting method.

[0007] To solve the above technical problems, the present invention comprises the following steps:

[0008] The grouting range of the goaf is divided into the collapse zone and the fracture zone. The grouting radius of the collapse zone and the fracture zone under the condition of isobaric grouting is determined by grouting in the experimental area. The collapse zone and the fracture zone share the same borehole for grouting. The grouting radius of the collapse zone is used as an indicator to design the borehole spacing for grouting filling. The collapse zone and the fracture zone are filled by taking advantage of the difference in the gap size between the collapse zone and the fracture zone.

[0009] Inject mineralized materials and industrial waste gas into the goaf. The injected mineralized material slurry can react with the industrial waste gas, fix the industrial waste gas and support the goaf at the same time.

[0010] The sealing condition of the goaf is detected using tracer gas, and then grouting is performed to seal the areas with poor sealing to complete the sealing of the goaf.

[0011] The present invention provides an old goaf CO 2 The mineralization grouting method comprises the following steps:

[0012] According to the actual situation of the strata in the working area, theoretical calculations are carried out, combined with drilling observations, to determine the height of the collapse zone and fracture zone in the goaf;

[0013] Determine the slurry diffusion radius of the collapse zone and the crack zone under the condition of isobaric grouting by grouting in the experimental area; calculate or measure the treatment area along the long and short axes of the building on the horizontal plane as D x , D y ;

[0014] According to the scope of the treatment area, curtain holes are arranged around the treatment area, and grouting holes are arranged in its central area;

[0015] Determine the drilling diameter, drilling depth and final hole position of the curtain hole and grouting hole, and determine the hole pressure;

[0016] After determining the drilling positions of all curtain holes and grouting holes, select the grouting hole at the center of the central area as the tracer gas release hole. After drilling, use tracer gas to detect the sealing condition of the goaf, and perform grouting to seal the poorly sealed areas. After sealing, perform tracer experiments again to ensure that the inside of the goaf is completely sealed.

[0017] Calculate the spatial volume V of the goaf according to the range of the goaf and the height of the collapse zone and the fracture zone 1 , and then calculate the total amount of slurry that can be injected as Q 1 Then, the total injection amount of industrial waste gas Q is determined according to the slurry mineralization capacity of industrial waste gas 2 ;

[0018] Add water to the mineralized material to make pulp, and after the pulping is completed, inject it into the goaf through the grouting hole; lay a pressure pipeline, and inject the collected industrial waste gas into the central area of ​​the treatment area through the pressure pipeline;

[0019] Grouting is performed into the treatment area through the curtain holes to achieve the purpose of completely filling the surrounding area of ​​the treatment area. After all the curtain holes are grouted, grouting is performed into the central area of ​​the treatment area, and slurry and industrial waste gas are injected into the central area through the grouting holes.

[0020] Preferably, the method for determining the slurry diffusion radius of the collapse zone and the fracture zone is:

[0021] Taking the grouting hole as the center, multiple groups of observation holes are arranged on the outer periphery of the grouting hole, and each group of observation holes is arranged on the same outer diameter of the grouting hole;

[0022] First, observe the slurry diffusion in the collapse zone and fracture zone in the area with an outer diameter of 40m, then observe the slurry diffusion in the collapse zone and fracture zone in the area with an outer diameter of 20m, and determine the slurry diffusion boundary position of the collapse zone and fracture zone;

[0023] Then observe the boreholes with an outer diameter of 10m or 30m, and so on, observe the slurry diffusion boundaries of the collapse zone and fracture zone, and obtain the slurry diffusion radii of the collapse zone and fracture zone as R and R respectively. 1 .

[0024] Preferably, in order to completely fill the collapse zone, the inscribed square of a circle with the slurry diffusion radius as the inner diameter is taken, and the corrected slurry diffusion radius is obtained as , at this time the collapse zone is completely filled;

[0025] Grouting filling of fracture zone, reference strip filling, grouting diffusion radius R of fracture zone 1 is the width of the strip filling, and the corrected slurry diffusion radius is , the difference in the slurry diffusion radius of the fracture zone is the unfilled width of the strip.

[0026] Preferably, the treatment area range along the long and short axes of the building is calculated or measured on the spot as D x , D y , then the number of holes drilled is .

[0027] Preferably, each group of observation holes is provided with three observation holes, and the observation holes on the same outer diameter are arranged in an equilateral triangle.

[0028] Preferably, the curtain holes and grouting holes are arranged as follows: the curtain holes are arranged with a drilling spacing smaller than the slurry diffusion radius of the corrected collapse zone, and the grouting holes are arranged with a drilling spacing with a slurry diffusion radius that can completely fill the corrected collapse zone.

[0029] Preferably, SF 6 As a tracer gas, it is released into the goaf through the selected release holes;

[0030] SF 6 After release, seal the top of the release hole, and then use monitoring equipment to monitor the SF in the goaf in real time. 6 Each curtain hole and grouting hole is used as a monitoring point. According to the SF 6 The concentration can be used to infer the leak location;

[0031] After confirming the leakage according to the monitoring results, grouting is immediately carried out to the leakage point to stop the leakage.

[0032] Preferably, the injection amount of slurry and industrial waste gas is:

[0033] Since the volume of the goaf space accounts for the total coal mining volume V 2 30% of V 1 =0.3V 2 To ensure that the goaf is completely sealed after grouting, the total volume of slurry Q1 The volume of the goaf should be V 1 Slightly larger, i.e. Q 1 =1.1V 1 ;

[0034] After conducting mineralization experiments under laboratory conditions, the ratio of slurry mineralization industrial waste gas is R, and the total injection amount of industrial waste gas is Q 2 =Q 1 ×R.

[0035] The present invention also provides an application of a mineralization grouting method in the longwall full span fall method for mining old goaf areas, wherein the old goaf CO 2 Mineralization grouting method.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention provides an old goaf CO 2 The mineralization grouting method is particularly suitable for longwall full-span mining of old goafs. It not only has a small amount of drilling work and relatively low grouting filling costs, but is also simple to operate. It can complete the mineralization management of old goafs and seal industrial waste gas for full utilization.

[0038] The drilling spacing of the present invention is more reasonably set, which can ensure that the collapse zone is completely filled and the crack zone is filled in strips, while reducing the number of drilling holes. The initial investment and preparation time are less than the traditional ones; and the present invention can reduce the usage of grouting raw materials, thereby reducing the grouting filling cost, while ensuring the grouting effect.

[0039] Since there are many residual voids in the collapse zone and the collapse zone is partially filled, the overlying rock strata will inevitably sink unevenly over time, which will inevitably affect the upper buildings; while there are not many voids in the fracture zone, and it gradually closes during the mining process, and the residual voids are very few. If it is not filled, it will only cause very slight sinking, which will not affect the upper buildings; therefore, it is only necessary to fill the collapse zone completely, and there will be no hidden danger of damage to the upper buildings. The present invention completes the sealing of industrial waste gas while completing the mineralization treatment of the old goaf. After the industrial waste gas is captured and pressurized, it is injected into the goaf to react with the slurry and is sealed underground, which effectively reduces environmental pollution. The products generated after the reaction with the slurry play a supporting and protective role on the goaf, and have a positive effect on environmental protection and treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0041] Figure 1 It is a structural schematic diagram of the grouting system of the present invention;

[0042] Figure 2 This is a schematic diagram of the drilling arrangement in the test area of ​​the present invention;

[0043] Figure 3 It is a schematic diagram of the arrangement of curtain holes and grouting holes of the present invention;

[0044] Figure 4 It is a schematic diagram of the drilling arrangement of the present invention;

[0045] Figure 5 This is the concentration distribution diagram of the tracer experiment of the present invention.

[0046] Symbols in the figure:

[0047] 1. Collapse zone; 2. Fracture zone; 3. Coal seam; 4. Bedrock; 5. Topsoil layer; 6. Water storage tank; 7. Primary mixing drum; 8. Secondary mixing drum; 9. Screening machine; 10. Slurry storage tank; 11. Slurry stopper; 12. Central grouting pipe; 13. Bottom plate; 14. Grouting hole; 15. Observation hole; 16. Curtain hole; 17. Fracture zone grouting; 18. Grouting in collapse zone. DETAILED DESCRIPTION

[0048] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0049] See also Figure 1 The present invention provides an old goaf CO 2 The mineralization grouting method comprises the following steps:

[0050] The grouting range of the goaf is divided into collapse zone 1 and fracture zone 2. The slurry diffusion radius of collapse zone 1 and fracture zone 2 under isobaric grouting conditions is determined through grouting in the experimental area. Collapse zone 1 and fracture zone 2 share the same borehole for grouting. The slurry diffusion radius of collapse zone 1 is taken as an indicator to design the borehole spacing for grouting filling. The natural difference in the gap size between collapse zone 1 and fracture zone 2 is used to achieve the purpose of filling the collapse zone 1 completely and filling the fracture zone 2 strips.

[0051] Attached Figure 1 Among them, 1 is the collapse zone; 2 is the fracture zone; 3 is the coal seam; 4 is the bedrock; and 5 is the topsoil layer.

[0052] Inject mineralized materials and industrial waste gas into the goaf. The injected mineralized material slurry can react with the industrial waste gas, fix the industrial waste gas and support the goaf at the same time;

[0053] In order to prevent the leakage of industrial waste gas injected into the old goaf later, the sealing condition of the old goaf is detected in advance using tracer gas, and then grouting is carried out to plug the leaks in the areas with poor sealing according to the specific situation to complete the complete sealing of the goaf.

[0054] Specifically, the present invention provides an old goaf CO 2 The mineralization grouting method comprises the following steps:

[0055] 1. According to the actual situation of the strata in the working area, theoretical calculations were carried out in reference to the "Regulations on the Retention and Compressed Coal Mining of Coal Pillars in Buildings, Water Bodies, Railways and Wells and Lanes", and the height H of the collapse zone 1 in the goaf area was determined in combination with drilling observations. 1 and the height H of the fracture zone 2 2 .

[0056] Second, determine the slurry diffusion radius of the collapse zone and fracture zone under isobaric grouting conditions through grouting in the experimental area;

[0057] The method for determining the slurry diffusion radius of the collapse zone 1 and the crack zone 2 is as follows: with the grouting hole 14 as the center, multiple groups of observation holes 15 are arranged on the periphery of the grouting hole 14, and each group of observation holes 15 is arranged on the circumference of the same outer diameter located outside the grouting hole 14; Figure 2 As shown in the figure, first observe the slurry diffusion in the collapse zone and fracture zone in the area with an outer diameter of 40m, then observe the slurry diffusion in the collapse zone and fracture zone in the area with an outer diameter of 20m, determine the slurry diffusion boundary position of the collapse zone and fracture zone, then observe the borehole with an outer diameter of 10m or 30m, and so on, observe the slurry diffusion boundary of the collapse zone and fracture zone, and obtain the slurry diffusion radius of the collapse zone and fracture zone, which are R and R respectively. 1 .

[0058] Furthermore, as a preferred embodiment of the present invention, each group of observation holes is provided with three observation holes 15 in total, and the three observation holes 15 provided on the same outer diameter are arranged in an equilateral triangle.

[0059] When the slurry diffusion radius of the collapse zone 1 and the fracture zone 2 is obtained, the slurry diffusion radius also needs to be corrected.

[0060] Specifically, in order to completely fill the collapsed zone, the inscribed square of the circle with the slurry diffusion radius as the inner diameter is taken, and the corrected slurry diffusion radius can be obtained as , at this time the collapse zone is completely filled; for the grouting filling of the fracture zone, refer to the strip filling, the grouting diffusion radius of the fracture zone is R 1 is the width of the strip filling, and the corrected slurry diffusion radius is , the difference in the slurry diffusion radius of the fracture zone is the unfilled width of the strip.

[0061] For the fracture zone, since there are not many residual voids, the strip filling ratio is ,when hour, , hour, , generally The value will not be greater than , so it will not cause any harmful impact on the surface.

[0062] Furthermore, the treatment area along the long and short axes of the building is calculated or measured on the spot as D x , D y , then the number of holes drilled is ,Analysis shows that when the drilling distance is enlarged, the number of drilling holes is reduced, thereby reducing the drilling footage.

[0063] 3. According to the scope of the treatment area, curtain holes are arranged around the treatment area, and grouting holes are arranged in the central area; Figure 3 As shown, curtain holes 16 are arranged at a drilling distance smaller than the corrected slurry diffusion radius of the collapse zone, and grouting holes 14 are arranged at a drilling distance with a slurry diffusion radius that can completely fill the collapse zone after correction; in the figure, 17 is the fracture zone grouting, and 18 is the collapse zone grouting.

[0064] Furthermore, the curtain hole 16 drilling distance L 1 < , arranged around the goaf. Since the drilling distance is smaller than the corrected slurry diffusion radius of the collapse zone, the slurry after grouting can diffuse to the surrounding through the curtain holes and completely penetrate the goaf, thereby achieving the effect of completely sealing the goaf.

[0065] Drilling distance L of grouting holes 2 = After grouting, the collapse zone in the central area is completely filled and the fracture zone is partially filled.

[0066] 4. Determine the borehole diameter, borehole depth and final hole position of the curtain hole 16 and the grouting hole 14, and determine the orifice pressure through a water pressure test;

[0067] Specifically, Figure 4 As shown, 1 is the collapse zone, 2 is the fracture zone, 3 is the coal seam, 4 is the bedrock, 5 is the topsoil layer, and 13 is the bottom plate.

[0068] A prefabricated concrete well plate is set on the wall of the curtain hole, and cement is used to seal the wall. The drilling diameter of the curtain hole and the grouting hole is not less than Φ130mm. The borehole passes through the loose layer and is drilled to the complete bedrock section for 5m. The casing is lowered and the pipe is fixed with cement mortar to protect the wall. After the borehole pipe is consolidated, a water pressure test is carried out to understand the development of rock fractures and the permeability. It is an in-situ test with a maximum pressure of not less than 3Mpa to ensure that there is no slurry leakage. After that, a borehole with a diameter of not less than Φ89mm is drilled downward, and the final hole position is 2m below the bottom plate of the coal seam to be filled.

[0069] Furthermore, as a preferred embodiment of the present invention, the hole position deviation of all drill holes is less than 1m and the hole inclination is less than 1°.

[0070] 5. After determining the drilling positions of all curtain holes and grouting holes, select the grouting hole at the center of the central area as the tracer gas release hole. First, drill at the hole position according to the above requirements. The remaining curtain holes and grouting holes should be drilled after the tracer test.

[0071] Specifically, using SF 6 As a tracer gas, SF 6 As a widely used tracer gas, it has stable chemical properties, is colorless and odorless at room temperature and pressure, does not react with acids, alkalis, and salts, and has excellent performance. It is released into the goaf through the selected release holes. 6 After release, the top of the release hole is sealed, and then the SF in the goaf is monitored in real time using monitoring instruments. 6 Each curtain hole and grouting hole is used as a monitoring point. According to the SF 6 The concentration of SF collected at each monitoring point can be used to infer the leakage location; 6 The concentration is different, and the SF is inferred according to the law of diffusion movement. 6 The monitoring point with higher concentration is the leakage point.

[0072] Then, after confirming the leakage according to the monitoring results, grouting is immediately carried out to the leakage point to plug the leakage; first determine the scope of the leakage, and according to the SF of each monitoring point 6 concentration, draw a concentration distribution diagram, and select the grouting location. Figure 5 As shown in the figure, the concentration distribution diagram is divided into three areas from the inside to the outside, namely high, medium and low. The leakage location should be in the high concentration area. The center of the high concentration area is taken as the grouting point. After drilling downwards, grouting is performed. The drilling method and grouting method are the same as above. After the plugging is completed, the tracer test is performed again. If the detection finds that there is still a leak, the above steps are repeated to plug the leak until the inside of the goaf is completely sealed.

[0073] 6. Calculate the spatial volume V of the goaf based on the scope of the goaf and the height of the collapse zone and the fracture zone 1, and then calculate the total amount of slurry that can be injected as Q 1 Then, the total injection amount of industrial waste gas Q is determined according to the slurry mineralization capacity of industrial waste gas 2 .

[0074] Specifically, according to the actual experience of goaf management, the volume of goaf space accounts for about V of the total coal mining volume of the goaf. 2 30% of V 1 =0.3V 2 To ensure that the goaf is completely sealed after grouting, the total volume of slurry Q 1 The volume of the goaf should be V 1 Slightly larger, i.e. Q 1 =1.1V 1 ;

[0075] After conducting mineralization experiments under laboratory conditions, the ratio of slurry mineralization industrial waste gas is R, and the total injection amount of industrial waste gas is Q 2 =Q 1 ×R.

[0076] Furthermore, for the calculation of R, for example, when 1L of slurry can mineralize 0.15L of supplementary pressurized industrial waste gas, then R=0.15.

[0077] 7. Add water to the mineralized material to make a slurry. After the slurry is made, use a grouting pump to inject it into the goaf through the grouting holes. Then, capture and pressurize the industrial waste gas generated by power plants and other industrial places, and then transport it into tank trucks, which are then transported to the treatment area for filling. Lay pressure pipelines, connect them to the tank truck delivery valves, lay the pipelines to the central area of ​​the treatment area, and connect and transport them according to the location of each grouting hole.

[0078] Specifically, Figure 1 As shown, the grouting process is as follows: first, the mineralized material (fly ash or other) is sent into the primary mixing drum 7 and water is added for the first mixing. The water storage tank 6 is used to store water. After flowing out, it passes through the screening machine 9 with a tube hoop with a hole of Φ3mm or a plane vibrating screen to remove the slag. After screening, the slurry below 3mm flows into the secondary mixing drum 8, and then cement (strength grade 32.5) is added for the second mixing; after mixing, it flows into the slurry storage tank 10, and then is transported to the borehole through the Φ50mm central grouting pipe 12 by a grouting pump. A slurry stopper 11 is provided on the grouting pipe, which is pressed from the flower pipe at the bottom of the grouting pipe into the coal and rock blocks in the goaf for grouting operation.

[0079] 8. Finally, grouting is carried out into the treatment area through the curtain holes to achieve the purpose of completely filling the surroundings within the treatment area. After all the curtain holes are grouted, grouting is carried out into the central area of ​​the treatment area. Slurry and industrial waste gas are injected into the central area through the grouting holes respectively. The injected industrial waste gas can be sealed without leakage.

[0080] Furthermore, as a preferred embodiment of the present invention, during the grouting process, when the pressure at the curtain hole mouth reaches 2.5-3.0 MPa and the pump volume is less than 30 L / min, the pressure is maintained for 30 minutes and the grouting is completed.

[0081] Specifically, the grouting process of the entire central area can be divided into n stages. Each stage includes two steps: injecting industrial waste gas and injecting slurry. The injection of industrial waste gas is first and then the injection of slurry. The injection amount of industrial waste gas and slurry in each stage should be: total injection amount / n. The grouting end standard is the final amount and final pressure. That is, when grouting the goaf, when the orifice pressure of the grouting hole reaches 2.5MPa and the pump volume is less than 30L / min, the pressure is maintained for 30 minutes.

[0082] The present invention provides an old goaf CO 2 The mineralization grouting method is particularly suitable for longwall full-span mining of old goafs. It not only has a small amount of drilling work and relatively low grouting filling costs, but is also simple to operate. It can complete the mineralization management of old goafs and seal industrial waste gas for full utilization.

[0083] The drilling spacing of the present invention is more reasonably set, which can ensure that the collapse zone is completely filled and the crack zone is filled in strips, while reducing the number of drilling holes. The initial investment and preparation time are less than the traditional ones; and the present invention can reduce the usage of grouting raw materials, thereby reducing the grouting filling cost, while ensuring the grouting effect.

[0084] Since there are many residual voids in the collapse zone and the collapse zone is partially filled, the overlying rock strata will inevitably sink unevenly over time, which will inevitably affect the upper buildings; while there are not many voids in the fracture zone, and it gradually closes during the mining process, and the residual voids are very few. If it is not filled, it will only cause very slight sinking, which will not affect the upper buildings; so it is only necessary to fill the entire collapse zone, and there will be no hidden danger of damage to the upper buildings. The present invention completes the sealing of industrial waste gas while completing the mineralization treatment of the old goaf. After the industrial waste gas is captured and pressurized, it is injected into the goaf to react with the slurry and is sealed underground, which effectively reduces environmental pollution, and the products generated after the reaction with the slurry play a supporting and protective role on the goaf, which has a positive effect on environmental protection and treatment.

[0085] In the description of the present invention, it is necessary to understand that the orientation or positional relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, in the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0086] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A CO 2 Mineralization grouting method, It is characterized in that The steps include: The grouting range of the goaf is divided into the collapse zone and the fracture zone. The grouting radius of the collapse zone and the fracture zone under the condition of isobaric grouting is determined by grouting in the experimental area. The collapse zone and the fracture zone share the same borehole for grouting. The grouting radius of the collapse zone is used as an indicator to design the borehole spacing for grouting filling. The collapse zone and the fracture zone are filled by taking advantage of the difference in the gap size between the collapse zone and the fracture zone. Inject mineralized materials and industrial waste gas into the goaf. The injected mineralized material slurry can react with the industrial waste gas, fix the industrial waste gas and support the goaf at the same time. Use tracer gas to detect the sealing condition of the goaf, then inject grout to seal the poorly sealed areas to completely seal the goaf; The method for determining the slurry diffusion radius of the collapse zone and fracture zone is: Taking the grouting hole as the center of the circle, multiple groups of observation holes are arranged on the outer periphery of the grouting hole, and each group of observation holes is arranged on the same outer diameter of the grouting hole; First, observe the slurry diffusion in the collapse zone and fracture zone in the area with an outer diameter of 40m, then observe the slurry diffusion in the collapse zone and fracture zone in the area with an outer diameter of 20m, and determine the slurry diffusion boundary position of the collapse zone and fracture zone; Then observe the boreholes with an outer diameter of 10m or 30m, and so on, observe the slurry diffusion boundaries of the collapse zone and fracture zone, and obtain the slurry diffusion radii of the collapse zone and fracture zone as R and R respectively. 1 ; In order to completely fill the collapse zone, the inscribed square of the circle with the slurry diffusion radius as the inner diameter is taken, and the corrected slurry diffusion radius is obtained as , at this time the collapse zone is completely filled; Grouting filling of fracture zone, reference strip filling, grouting diffusion radius R of fracture zone 1 is the width of the strip filling, and the corrected slurry diffusion radius is .

2. The old goaf CO according to claim 1 2 Mineralization grouting method, It is characterized in that Calculate or measure the treatment area along the long and short axes of the building on the horizontal plane as D. x , D y , then the number of holes drilled is .

3. The old goaf CO according to claim 1 2 Mineralization grouting method, It is characterized in that Each group of observation holes is provided with three observation holes, and the observation holes on the same outer diameter are arranged in an equilateral triangle.

4. A CO 2 Mineralization grouting method, It is characterized in that The steps include: According to the actual situation of the strata in the working area, theoretical calculations are carried out, combined with drilling observations, to determine the height of the collapse zone and fracture zone in the goaf; Determine the slurry diffusion radius of the collapse zone and the crack zone under the condition of isobaric grouting by grouting in the experimental area; calculate or measure the treatment area along the long and short axes of the building on the horizontal plane as D x , D y ; According to the scope of the treatment area, curtain holes are arranged around the treatment area, and grouting holes are arranged in its central area; Determine the drilling hole diameter, drilling depth and final hole position of the curtain hole and grouting hole, and determine the hole mouth pressure; a prefabricated concrete well plate is set on the wall of the curtain hole, and cement is used to seal the wall; the drilling hole diameter of the curtain hole and the grouting hole is not less than Φ130mm, and the casing is lowered after the hole passes through the loose layer and drills to the complete bedrock section for 5m, and cement mortar is used to fix the pipe and protect the wall. After the hole mouth pipe is consolidated, a water pressure test is carried out; then drill downward with a hole diameter of not less than Φ89mm, and excavate to 2m below the bottom plate of the coal seam to be filled as the final hole position; The arrangement of the curtain holes and the grouting holes is as follows: the curtain holes are arranged with a drilling interval smaller than the slurry diffusion radius of the corrected collapse zone, and the grouting holes are arranged with a drilling interval with a slurry diffusion radius that can completely fill the collapsed zone after correction; after grouting, the collapsed zone in the central area is completely filled, and the fracture zone is partially filled; After determining the drilling positions of all curtain holes and grouting holes, select the grouting hole at the center of the central area as the tracer gas release hole. After drilling, use tracer gas to detect the sealing condition of the goaf, and perform grouting to seal the poorly sealed areas. After sealing, perform tracer experiments again to ensure that the inside of the goaf is completely sealed. Calculate the spatial volume V of the goaf according to the range of the goaf and the height of the collapse zone and the fracture zone 1 , and then calculate the total amount of slurry that can be injected as Q 1 Then, the total injection amount of industrial waste gas Q is determined according to the slurry mineralization capacity of industrial waste gas 2 ; Add water to the mineralized material to make pulp, and after the pulping is completed, inject it into the goaf through the grouting hole; lay a pressure pipeline, and inject the collected industrial waste gas into the central area of ​​the treatment area through the pressure pipeline; Grouting is performed into the treatment area through the curtain holes to achieve the purpose of completely filling the surrounding areas within the treatment area. After all the curtain holes are grouted, grouting is performed into the central area of ​​the treatment area, and slurry and industrial waste gas are respectively injected into the central area through the grouting holes; The injection amount of slurry and industrial waste gas is: Since the volume of the goaf space accounts for the total coal mining volume V 2 30% of V 1 =0.3V 2 To ensure that the goaf is completely sealed after grouting, the total volume of slurry Q 1 The volume of the goaf should be V 1 big; After conducting mineralization experiments under laboratory conditions, the ratio of slurry mineralization industrial waste gas is R, and the total injection amount of industrial waste gas is Q 2 =Q 1 ×R.

5. The old goaf CO according to claim 4 2 Mineralization grouting method, It is characterized in that Adopt SF 6 As a tracer gas, it is released into the goaf through the selected release holes; SF 6 After release, seal the top of the release hole, and then use monitoring equipment to monitor the SF in the goaf in real time. 6 Each curtain hole and grouting hole is used as a monitoring point. According to the SF 6 The concentration of the leak can be used to infer the location of the leak; After confirming the leakage according to the monitoring results, grouting is immediately carried out to stop the leakage.

6. Application of a mineralization grouting method in longwall full-span mining of old goaf areas, It is characterized in that The old goaf CO used in any one of claims 1-5 2 Mineralization grouting method.

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