Integrated goaf filling treatment method

Abstract

The application provides a goaf integrated filling treatment method, which separates a large-area goaf into small-area goafs through filling isolation, and the small-area goafs are supported by combined support columns formed by dry filling, cementation filling and primary ore columns, and the combined support columns are used for supporting the roof of the goaf. The method adopts the advantages of low cost of dry filling and effective support of the roof by cementation filling, divides the goaf, forms a roof combined support body, studies a combined filling treatment technology of integral dry filling at the lower part and interval cementation roof connection at the upper part, divides the goaf through the combined support body, avoids large-area exposure of the roof of the goaf, effectively controls the ground pressure, prevents the ground surface from collapsing, and achieves the treatment effect of comprehensive cementation and paste body filling, and the filling cost is relatively reduced by 60%-90%.

Description

Technical Field

[0001] This invention relates to the field of filling and remediation technology for goaf areas in underground mining, and in particular to an integrated filling and remediation method for goaf areas. Background Technology

[0002] In my country's underground mining, the main methods for managing goaf areas include caving, sealing and isolation, and backfilling. Backfilling is the current and future main trend. Currently, the main backfilling methods used are dry backfilling, wet backfilling, and cemented backfilling. Dry backfilling utilizes tailings or waste rock to counter-pressure the original pillars in the goaf, enhancing their support effect. It fills to a depth of 1 meter from the roof, controlling the roof collapse height to around 1 meter. While simple and low-cost, it does not achieve the same level of ground pressure control as cemented backfilling. Its applicability is limited for areas with high safety requirements, where roof collapse or surface subsidence is not permitted. Wet backfilling and cemented backfilling use waste rock, tailings, and concrete as main raw materials to form a backfill body that supports the roof and replaces part of the pillars. They offer good management results, but are complex and costly, making them economically unfeasible for mining some low-yield mineral resources. Summary of the Invention

[0003] The main objective of this invention is to provide an integrated filling and treatment method for goaf areas, which solves the problems of insufficient manual prying height in roadways, and the inability to pry down roof and sidewalls due to insufficient manual strength, resulting in lower efficiency and the inability to perform tasks manually.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: an integrated filling and treatment method for goaf areas, which isolates large-area goaf areas into small-area goaf areas through filling and isolation. The small-area goaf areas are supported by a combined support column formed by dry filling, cemented filling and primary ore pillars. The combined support column is used to support the roof of the goaf area.

[0005] The filling method is as follows:

[0006] S1. Two rows of pillars are mined each time, and the goaf is dry-filled with tailings until it is 0.8-1.2 meters away from the roof.

[0007] S2. Repeat the mining and backfilling process of S1 until the goaf reaches the designed length in the dip direction, and complete the dry backfilling of the lower part of the goaf.

[0008] S3. Using the cutting roadway as the boundary, the goaf area is divided into two small goaf areas. Cemented backfilling is carried out on the dry material between the original pillars or backfill bodies around each small goaf area.

[0009] S4. The width of the cemented backfill is consistent with that of the original pillar. Support the two side templates, and the backfill body and the original pillar will eventually form an integral strip.

[0010] S5. Using the cutting tunnel as the center line, fill from both sides of the stope toward the middle.

[0011] S6. Repeat the above steps to eventually fill and isolate the goaf into multiple small goaf areas.

[0012] In the preferred embodiment, a ground pressure detection and observation channel is provided in the goaf area, and multiple ground pressure detection devices are installed inside the ground pressure detection and observation channel to detect the ground pressure in the goaf area.

[0013] In the preferred scheme, dry filling accounts for more than 90%, and cemented filling accounts for less than 10%.

[0014] In the preferred embodiment, the goaf is divided into multiple smaller goafs. The lower part of each smaller goaf is filled with dry material, and the upper part is cemented and connected to the roof, combined with the original ore pillars to form a combined filling isolation body, which at the same time forms a combined support pillar to support the roof of the goaf.

[0015] In the preferred scheme, dry filling includes mine waste rock and tailings. Dry filling directly uses mine production waste rock to fill the voids nearby. Since there is insufficient solid waste, tailings from the mine's ore dressing plant are utilized.

[0016] In the preferred embodiment, the cemented backfill includes coarse aggregate and fine aggregate. The coarse aggregate required for the cemented backfill concrete is 5-20mm tailings from a mineral processing plant. The fine aggregate required is 0-5mm manufactured sand obtained by crushing and screening the 5-20mm tailings using a sand making equipment.

[0017] In the preferred embodiment, the cemented backfill is distributed between the primary pillars and forms strip pillars with the primary pillars, reducing the amount of cemented backfill and forming an integral whole with the primary pillars to improve the support strength;

[0018] Dry backfill accounts for more than 80%, while cemented backfill accounts for less than 20%.

[0019] In the preferred scheme, the mix proportion of cementitious filling (4) is 220-260Kg of cement, 190-220Kg of water, 820-840Kg of sand, 900-1100Kg of gravel, 40-60Kg of fly ash, and 2-4Kg of admixture per cubic meter of concrete.

[0020] In the preferred embodiment, 40-60 kg of water is added to the cemented filling (4) mix ratio to increase the amount of slurry and allow it to seep into the lower dry material, so that the dry material solidifies and the overall filling strength is improved.

[0021] This invention provides an integrated backfilling and treatment method for goaf areas. By analyzing and studying the instability mode and scale of the surrounding rock in the mining area, this paper optimizes the backfilling materials and methods, and integrates dry backfilling, cemented backfilling and original pillars or backfilling bodies into an integrated roof support system with significantly improved support effect and greatly reduced cost. This achieves the purpose of improving the control effect of ground pressure in goaf areas and avoiding geological disasters such as surface collapse and cracking. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0023] Figure 1 These are construction diagrams for steps one through three of this invention;

[0024] Figure 2 These are construction diagrams for steps four and five of this invention;

[0025] Figure 3 This is a schematic diagram of the 48×48 meter small open area of ​​the present invention;

[0026] Figure 4 This is a schematic diagram of the 48×35 meter small open area of ​​the present invention.

[0027] In the diagram: 1. Ground pressure monitoring channel; 2. Ground pressure monitoring device; 3. Dry filling; 4. Cemented filling; 5. Primary pillar; 6. Lower dry and wet filling; 7. Upper cemented filling. Detailed Implementation

[0028] Example 1

[0029] like Figures 1-4 As shown, an integrated backfilling method for goaf remediation involves isolating a large goaf area into smaller goaf areas through backfilling. These smaller goaf areas are then supported by combined pillars formed from dry backfilling, cemented backfilling, and existing pillars. The combined pillars support the goaf roof. The backfill material and the existing pillars are integrated, and the original 4x4 support pillars are combined into a combined support structure before being returned to the mining stope. This method combines the advantages of low-cost dry backfilling and effective roof support through cemented backfilling. It employs a method of dividing the goaf area to form a combined roof support structure, and studies a combined backfilling remediation technology with integral dry backfilling at the bottom and intermittent cemented backfilling at the top. By dividing the goaf area through the combined support structure, large-area exposure of the goaf roof is avoided, effectively controlling ground pressure and preventing surface subsidence. This achieves the remediation effect of comprehensive cemented and paste backfilling, while reducing backfilling costs by 60%-90%.

[0030] The filling method is as follows:

[0031] S1. Two rows of pillars are mined each time, and the goaf is dry-filled with tailings until it is 0.8-1.2 meters away from the roof.

[0032] S2. Repeat the mining and backfilling process of S1 until the goaf reaches the designed length in the dip direction, and complete the dry backfilling of the lower part of the goaf.

[0033] S3. Using the cutting roadway as the boundary, the goaf area is divided into two small goaf areas. Cemented backfilling is carried out on the dry material between the original pillars or backfill bodies around each small goaf area.

[0034] S4. The width of the cemented backfill is consistent with that of the original pillar. Support the two side templates, and the backfill body and the original pillar will eventually form an integral strip.

[0035] S5. Using the cutting tunnel as the center line, fill from both sides of the stope toward the middle.

[0036] S6. Repeat the above steps to eventually fill and isolate the goaf into multiple small goaf areas.

[0037] In the room-and-pillar method of mining, after every four rows of pillars are formed, the spaces between the pillars in the stope are filled with dry material until they are within 1 meter of the roof. Then, cemented backfill is used between the original pillars around the four rows of pillars to connect the roof, while the original 4x4 pillars are connected to form a continuous combined backfill body, effectively isolating the goaf and forming a combined support structure of dry backfill + cemented backfill + original pillars to support the roof of the goaf.

[0038] In the preferred embodiment, a ground pressure monitoring and observation channel 1 is provided in the goaf area. Multiple ground pressure monitoring devices 2 are installed inside the channel 1 to monitor the ground pressure in the goaf area. By leaving only a few ground pressure inspection and observation channels in the goaf area, the exposed area of ​​the goaf is reduced by more than 86% compared to the conventional room-and-pillar method.

[0039] In the preferred scheme, dry filling 3 accounts for more than 90%, and cemented filling 4 accounts for less than 10%.

[0040] In the preferred embodiment, the goaf is divided into multiple smaller goafs. The lower part of each smaller goaf is filled with dry material, and the upper part is cemented and connected to the roof, combined with the original ore pillars to form a combined filling isolation body, which at the same time forms a combined support pillar to support the roof of the goaf.

[0041] In the preferred scheme, dry filling 3 includes mine waste rock and tailings. Dry filling directly uses mine production waste rock to fill the voids nearby. Since there is insufficient solid waste, tailings from the mine's beneficiation plant are utilized.

[0042] In the preferred embodiment, the cemented backfill 4 includes coarse aggregate and fine aggregate. The coarse aggregate required for the cemented backfill concrete is selected from tailings of 5-20mm from a mineral processing plant. The fine aggregate required is 0-5mm manufactured sand obtained by crushing and screening the 5-20mm tailings through a sand making equipment.

[0043] In the preferred embodiment, the cemented backfill is distributed between the primary pillars and forms strip pillars with the primary pillars, reducing the amount of cemented backfill and forming an integral whole with the primary pillars to improve the support strength;

[0044] Dry backfill accounts for more than 80%, while cemented backfill accounts for less than 20%.

[0045] In the preferred embodiment, the mix proportion of cementitious filling 4 is 220-260 kg of cement, 190-220 kg of water, 820-840 kg of sand, 900-1100 kg of gravel, 40-60 kg of fly ash, and 2-4 kg of admixture per cubic meter of concrete.

[0046] In the preferred embodiment, 40-60 kg of water is added to the cemented filling mix ratio 4 to increase the amount of slurry and allow it to penetrate into the lower dry material, thereby causing the dry material to solidify and improving the overall strength of the filling body.

[0047] Example 2

[0048] Further explanation in conjunction with Example 1, such as Figures 1-4 The structure shown illustrates that the combined dry and cemented backfilling technology for goaf remediation is based on backfill mining, further optimizing the backfilling scheme, increasing the backfill area to the roof, and segmenting and isolating the goaf, with the main objective of significantly improving the goaf remediation effect. The stability of goafs varies depending on the mining method; therefore, the parameters of the combined support structure can be adjusted accordingly based on the ground pressure control requirements to achieve the best support effect on the roof.

[0049] In conventional room-and-pillar mining followed by dry backfilling, the goaf relies on the original pillars to support the roof. Due to the integral nature of the original pillars with the roof, their support effect is better than that of the backfill. Furthermore, the counter-pressure of the dry backfill material on the pillars further strengthens the stability of the supporting pillars. When dividing the goaf, a single stope is divided into four smaller goafs of 48×48 meters. Figure 3 As shown, each small void is formed into a whole support structure by combining dry filling, cemented filling, and primary ore pillars.

[0050] In strip-filling two-step mining, wet point-pillar filling replaces the original pillars in the goaf, disrupting the integrity of the pillars and roof. The roof support effect is relatively poor compared to the original pillars. The roof support in the goaf should be strengthened, and the goaf area needs to be further reduced by dividing the single stope into six small goafs of 48×35 meters. Figure 4 As shown, each small empty area forms a whole support structure.

[0051] Filling cost

[0052] The calculation is based on a support structure that is 48 meters long, 48 meters wide, with an average height of 3 meters, a dry filling height of 2 meters, and a cemented filling height of 1 meter:

[0053] Dry backfilling: unit price 32.5 yuan / m³, backfilling volume (48*48-25*4)*2=4408m³, backfilling cost 32.5*4408=143260 yuan.

[0054] Cemented backfill: unit price 240 yuan / m³, backfill volume 4*7*16*1=448m³, backfill cost 270*448=120960 yuan;

[0055] Total cost: 143260 + 120960 = 264220 yuan, volume of void treated: (48*48 - 25*4) * 3 = 6612 m³, total cost: 264220 / 6612 = 39.9 yuan / m³.

[0056] The core of the ground pressure risk in goaf is the existence of the exposed area of ​​the goaf. This technology starts from this essential problem and reduces the exposed area of ​​the goaf by more than 86% compared with the ordinary room and column method, leaving only the ground pressure inspection and observation channel, effectively improving the safety factor. At the same time, it solves the problem that ground pressure cannot be observed and studied after the goaf is filled.

[0057] By using upper backfill to connect the roof, the backfill body and the original pillars are integrated into a whole. After the original 4*4 support pillars are combined into a joint support structure, only the roof area of ​​a few roadways in the goaf is exposed in the mining stope, eliminating the problem of large-scale roof exposure in the goaf. At the same time, the roof connection area of ​​the 100*100 meter standard mining stope increases from 1920㎡ to 3936㎡, an increase of 105%, and the support effect of the backfill body on the roof is also improved.

[0058] Make full use of mine solid waste to reduce backfilling costs

[0059] For both dry backfilling and cemented backfilling, over 90% of the raw materials are mine waste rock and tailings, with transportation costs being the main expense. Dry backfilling directly uses mine waste rock to fill nearby voids, achieving zero emissions of solid waste from mining operations. If there is insufficient solid waste, tailings from the mine's concentrator can be utilized. The coarse aggregate required for cemented backfill concrete is 5-20mm tailings from the concentrator. The required fine aggregate is obtained by crushing and screening the 5-20mm tailings into 0-5mm manufactured sand using sand making equipment.

[0060] With the development of integrated mining and beneficiation, the transportation cost of backfill materials can be further reduced, and the backfilling efficiency will be further improved.

[0061] Filling ratio and cemented filling proportion

[0062] Dry backfilling should extend to 1 meter from the top slab, minimizing the amount of cemented backfill while ensuring the safety and ease of formwork and pipe installation. Below 1 meter, personnel access will be difficult. Cemented backfill should be distributed between the primary pillars, forming strip pillars with them to reduce cemented backfill volume while maintaining a unified structure and increased support strength. Dry backfill should account for over 80%, while cemented backfill should account for less than 20%.

[0063] The cementitious filling concrete mix design was optimized for C10 grade. The theoretical mix proportion for C10 pumped concrete is 250 kg cement, 198 kg water, 837 kg sand, 1022 kg aggregate, 50 kg fly ash, and 3 kg admixture per cubic meter. By fully utilizing tailings and adjusting the mix proportions, field experiments yielded the following mix: 150 kg cement, 100 kg fly ash, 198 kg water, 1350 kg tailings sand, and 500 kg tailings. The expected cost is: 0.15*530 + 0.1*150 + 1.35*40 + 0.5*5.8 + 120 = 271.4 yuan / m³, approximately 270 yuan / m³.

[0064] On this basis, add 50 kg of water and a certain amount of slurry to allow it to seep into the lower dry material, promote the solidification of the dry material, and improve the overall strength of the filling body.

[0065] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A method for integrated backfilling and remediation of goaf areas, characterized by: By filling and isolating, the large-area goaf is isolated into small-area goafs. The small-area goafs are supported by a combination of dry filling, cemented filling and original pillars. The combination of pillars is used to support the roof of the goaf. The filling method is as follows: S1. Two rows of pillars are mined each time, and the goaf is dry-filled with tailings until it is 0.8-1.2 meters away from the roof. S2. Repeat the mining and backfilling process of S1 until the goaf reaches the designed length in the dip direction, and complete the dry backfilling of the lower part of the goaf. S3. Using the cutting roadway as the boundary, the goaf area is divided into two small goaf areas. Cemented backfilling is carried out on the dry material between the original pillars or backfill bodies around each small goaf area. S4. The width of the cemented backfill is consistent with that of the original pillar. Support the two side templates, and the backfill and the original pillar will eventually form an integral strip. Cemented filling is distributed between primary pillars and forms strip pillars with the primary pillars, reducing cemented filling while forming an integral whole with the primary pillars, thus improving support strength; Dry backfill accounts for more than 80%, while cemented backfill accounts for less than 20%. Cemented filling (4) The mix proportion is 220-260Kg of cement, 190-220Kg of water, 820-840Kg of sand, 900-1100Kg of gravel, 40-60Kg of fly ash and 2-4Kg of admixture per cubic meter of concrete; Based on the cemented filling (4) mix ratio, add 40-60 kg of water to increase the amount of grout so that it can seep into the lower dry material, causing the dry material to solidify and improving the overall strength of the filling body; S5. Using the cutting tunnel as the center line, fill from both sides of the stope toward the middle. S6. Repeat the above steps to finally fill and isolate the goaf into multiple small goaf areas; The goaf area is equipped with a ground pressure detection and observation channel (1), and multiple ground pressure detection devices (2) are installed inside the ground pressure detection and observation channel (1). The ground pressure detection devices (2) are used to detect the ground pressure in the goaf area. Dry filling (3) accounts for more than 90%, and cemented filling (4) accounts for less than 10%; The goaf is divided into multiple small goafs. The lower part of the small goaf is filled with dry material, and the upper part is cemented and connected to the roof, combined with the original ore pillars to form a combined filling isolation body, which at the same time forms a combined support pillar to support the roof of the goaf. Dry filling (3) includes mine waste rock and tailings. Dry filling directly uses mine production waste rock to fill the voids nearby. There is insufficient solid waste, so tailings from the mine beneficiation plant are used. Cemented backfill (4) includes coarse aggregate and fine aggregate. The coarse aggregate required for cemented backfill concrete is tailings of 5-20mm from the mineral processing plant. The fine aggregate required is 0-5mm manufactured sand obtained by crushing and screening the 5-20mm tailings through a sand making equipment.

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