A method for underground treatment of coal mine water

Abstract

This invention discloses an underground treatment method for coal mine water. The method involves purifying the mine water underground by using the first goaf in front of the ongoing mining work to perform preliminary purification, and using a second goaf in front of the ongoing mining work to seal the concentrated brine. The water treatment equipment is placed in the existing underground roadways and chambers, which does not occupy surface land. The self-purification effect of the collapsed rock mass in the goaf is utilized to reduce the cost of mine water treatment. The concentrated brine after deep treatment can be stored in a suitable goaf to avoid the risk of solid waste pollution caused by the crystallization and evaporation of crystal salt.

Description

Technical Field

[0001] This invention relates to the field of coal mining and mine water treatment technology, and in particular to an underground treatment method for coal mine water. Background Technology

[0002] Coal mining generates mine water. After treatment, most of the mine water can be reused, while the wastewater (concentrated brine) generated requires special treatment or storage.

[0003] Traditional mine water treatment processes typically employ surface treatment methods, using conventional surface water treatment facilities. Some mine water meets reuse standards and is returned underground for reuse. However, surface treatment methods have drawbacks such as high infrastructure investment, high operating costs for mine water pumping, and large land area requirements. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a novel method for underground treatment of coal mine water. This method purifies the mine water underground by utilizing the first goaf in front of the ongoing mining work to perform preliminary purification, and then using a second goaf in front of the ongoing mining work to seal the concentrated brine. Water treatment equipment is placed in existing underground roadways and chambers, thus avoiding the occupation of surface land. The self-purification effect of the collapsed rock mass in the goaf is utilized, reducing the cost of mine water treatment. The deeply treated concentrated brine can be stored in a suitable goaf, avoiding the risk of solid waste pollution from crystallized salt produced after crystallization and evaporation.

[0005] The present invention provides a method for underground treatment of mine water in coal mines, comprising the following steps:

[0006] S01: Excavation to form tunnels, underground water tanks, and vertical shafts;

[0007] S02: Along the direction of the roadway extension, multiple strip-shaped longwall faces are divided in sequence and marked as longwall face No. 1, longwall face No. 2, ..., longwall face n. Correspondingly, the goaf formed after subsequent longwall mining is named goaf area No. 1, goaf area No. 2, ..., goaf area n, where n is a positive integer greater than or equal to 3.

[0008] S03: Mining proceeds sequentially from mining face 1 to mining face n, and the mine water generated during the mining process is temporarily stored in an underground water tank.

[0009] Among them, a mine water purification and treatment system was built in the roadway before the No. 2 longwall face was mined out;

[0010] S04: During the mining process from the No. 3 longwall face to the nth longwall face:

[0011] The mine water temporarily stored in the underground water tank is diverted to the first goaf area before the mining face that is being mined for preliminary purification. The preliminarily purified mine water is then transported to the mine water purification system for further purification. The mine water obtained after purification by the mine water purification system is then piped out for use.

[0012] The concentrated brine produced after treatment by the mine water purification system is led to the second goaf area, located before the ongoing mining face, for storage.

[0013] In one of the optional technical solutions, step S04 includes:

[0014] After the formation of Goaf No. 2, and during the mining of Goaf No. 3, the mine water temporarily stored in the underground water tank is piped to Goaf No. 2 for preliminary purification. The mine water after preliminary purification in Goaf No. 2 is piped to the mine water purification system for further purification. The mine water obtained after purification by the mine water purification system is piped out for use. The concentrated brine produced after purification by the mine water purification system is piped to Goaf No. 1.

[0015] After the No. 3 goaf is formed, and during the mining of the No. 4 mining face, the No. 1 goaf is sealed off. The mine water temporarily stored in the underground water tank is piped to the No. 3 goaf for preliminary purification. The concentrated brine produced after treatment by the mine water purification system is piped to the No. 2 goaf, and so on, until the No. n mining face is mined out.

[0016] One of the optional technical solutions includes, after the nth longwall face has been mined, the following:

[0017] The mine water temporarily stored in the underground water tank is piped to the nth goaf for preliminary purification. The concentrated brine produced after treatment by the mine water purification system is piped to the n-1th goaf. After the first preset time, the n-1th goaf is sealed.

[0018] In one of the alternative technical solutions, after sealing off goaf n-1, the following is also included:

[0019] Mine water temporarily stored in the underground water tank is piped to the mine water purification system;

[0020] The concentrated brine produced after treatment by the mine water purification system is piped to goaf area n. After a second preset time, goaf area n is sealed off.

[0021] In one of the optional technical solutions, step S04 includes: the mine water, after preliminary purification in the goaf, is led to the surface through a pipeline for reuse in production.

[0022] In one of the alternative technical solutions, the mine water, after preliminary purification in the goaf, is piped to a coal washing plant for coal washing; and / or, the mine water, after preliminary purification in the goaf, is piped to a coal-fired power plant for machine cooling.

[0023] In one of the optional technical solutions, the mine water purification system includes a primary purification system, a secondary purification system, and a tertiary purification system;

[0024] The mine water, after initial purification in the goaf area, is piped to the primary purification system.

[0025] Mine water that has been purified by the primary purification system is piped to the secondary purification system.

[0026] Mine water that has been purified by the secondary purification system is piped to the tertiary purification system.

[0027] The mine water, after being purified by the three-stage purification system, is piped to the surface for domestic use. The concentrated brine obtained after the three-stage purification system is then sealed in the second goaf area before the mining face that is currently being mined.

[0028] In one of the alternative technical solutions, a portion of the mine water purified by the primary purification system is also piped to the longwall face where it is being mined, for machine cooling and dust removal.

[0029] In one of the alternative technical solutions, a portion of the mine water, after being purified by the secondary purification system, is also piped to an above-ground reservoir for irrigation.

[0030] In one of the alternative technical solutions, the mine water, after being purified by a three-stage purification system, is piped to a waterworks.

[0031] The above technical solution has the following beneficial effects:

[0032] The underground treatment method for coal mine water provided by this invention purifies the mine water underground. Starting from the No. 3 longwall face, the first goaf in front of the longwall face being mined is used for preliminary purification of the mine water. The second goaf in front of the longwall face being mined is used to seal the concentrated brine. During the mining process of each longwall face, there will always be a goaf used for preliminary purification of the mine water and a goaf used for sealing the concentrated brine. The goaf used for preliminary purification and the goaf used for sealing the concentrated brine are alternated in sequence, so that all goafs can be used and all concentrated brine can be stored.

[0033] The underground treatment method for coal mine water provided by this invention utilizes existing underground roadways and chambers to place water treatment equipment, without occupying surface land. It also utilizes the self-purification effect of collapsed rock masses in the goaf to reduce the cost of mine water treatment. The concentrated brine after deep treatment can be stored in a suitable goaf to avoid the risk of solid waste pollution caused by crystallized salt after crystallization and evaporation. Attached Figure Description

[0034] The disclosure of this invention will become more readily understood by referring to the accompanying drawings. It should be understood that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings:

[0035] Figure 1 A schematic diagram of the steps of an underground coal mine water treatment method according to an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram illustrating the use of goaf 1 to store concentrated brine and goaf 2 for preliminary filtration during the mining of goaf 3. Detailed Implementation

[0037] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. Identical components are indicated by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, while the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0038] like Figure 1-2 As shown, an embodiment of the present invention provides a method for underground treatment of coal mine water, comprising the following steps:

[0039] S01: Excavation forms tunnel 10, underground water tank 20, and vertical shaft 30.

[0040] S02: Along the direction of the roadway extension, multiple strip-shaped longwall faces 50 are sequentially divided and marked as longwall face No. 1, longwall face No. 2, ..., longwall face n. Correspondingly, the goaf areas 60 formed after subsequent longwall mining are named goaf area No. 1, goaf area No. 2, ..., goaf area n, where n is a positive integer greater than or equal to 3.

[0041] S03: Mining proceeds sequentially from mining face 1 to mining face n. The mine water generated during the mining process of each mining face 50 is temporarily stored in the underground water tank 20.

[0042] Before the No. 2 longwall face was fully mined, a mine water purification system 40 was constructed in roadway 10.

[0043] S04: During the mining process from the No. 3 longwall face to the nth longwall face:

[0044] The mine water temporarily stored in the underground water tank 20 is led to the first goaf 60, which is located before the mining face 50, which is being mined, for preliminary purification. The preliminarily purified mine water is then transported to the mine water purification system 40 for further purification. The mine water obtained after purification by the mine water purification system 40 is then led out through pipelines for use.

[0045] The concentrated brine produced after treatment by the mine water purification system 40 is led to the second goaf 60, which is located before the mining face 50 that is being mined, for storage.

[0046] The method for treating mine water in coal mines provided by this invention treats, classifies, and utilizes mine water during coal mining.

[0047] Specifically, it includes the following steps:

[0048] Step 1: Initial preparation work, including excavation to form roadway 10, underground water chamber 20, and vertical shaft 30. Underground water chamber 20 is an underground chamber; multiple underground chambers can be used to construct multiple underground water chambers 20 as needed. A water system, including pumps, control systems, and pipelines 70, will be built outside the underground water chamber 20. This system is used to temporarily store mine water or production wastewater generated from the longwall face 50 in the underground water chamber 20, and also to transport the mine water from the underground water chamber 20 to a goaf area 60 for preliminary purification using collapsed rock. The pumps, control systems, and pipelines 70 are standard installations and will not be described in detail here.

[0049] Shaft 30 connects the surface to tunnel 10 and is used to lay pipeline 70.

[0050] Step 2: Preparatory work before mining. Coal mining adopts a strip mining method, dividing the length of roadway 10 into multiple spaced mining faces 50. The mining direction of the mining faces 50 is approximately perpendicular to roadway 10. For ease of description, along the direction from one end of roadway 10 to shaft 30, the multiple mining faces 50 are sequentially labeled as Mining Face No. 1, Mining Face No. 2...n, a positive integer greater than or equal to 3. Also for ease of description, according to the sequence number of the mining faces 50, the goaf 60 formed after subsequent mining is sequentially named Goaf No. 1, Goaf No. 2...n. After each goaf 60 is formed, the opening connecting it to roadway 10 is sealed to form an underground reservoir for filtering mine water and storing underground water. In the following description, the goaf areas used for filtration and storage are all underground reservoirs. That is, goaf area No. 1, goaf area No. 2, ..., goaf area n correspond to underground reservoir No. 1, underground reservoir No. 2, ..., underground reservoir n.

[0051] Step 3: Mining begins at working face 50, proceeding sequentially from working face 1 to working face n. During the mining of each working face 50, the pipes 70 of the underground water sump 20 are connected to the water outlet (e.g., a water storage ditch / trough) of each working face 50 to guide the mine water generated during the mining process to the underground water sump 20 for temporary storage. For example, the mine water generated during the mining of working face 1 is temporarily stored in one or more underground water sump 20s, the mine water generated during the mining of working face 2 is also temporarily stored in one or more underground water sump 20s, and the mine water generated during the mining of subsequent working faces 3, 4…n is also temporarily stored in one or more underground water sump 20s. Starting from the No. 3 longwall face, the mine water in the underground water tank 20 begins to be transported to the goaf 60, where it undergoes preliminary purification.

[0052] Before the No. 2 longwall face is fully mined, a mine water purification system 40 needs to be constructed in roadway 10. The mine water purification system 40 is constructed in one or more chambers on one side of roadway 10. The mine water purification system 40 is used to further purify the mine water that has undergone preliminary purification in the goaf 60, obtaining reusable mine water and wastewater (concentrated brine) that needs to be sealed. The mine water purification system 40 can employ a combination of ultrafiltration, reverse osmosis, and membrane distillation purification systems.

[0053] Step 4: During the mining process from face 3 to face n, the mine water purification treatment method is as follows:

[0054] Using the ongoing mining face 50 as a reference, the water supply pipeline 70 of the underground water reservoir 20 is connected to a higher elevation point in the first goaf 60 preceding the ongoing mining face 50. The mine water injected into this goaf flows by gravity to a lower elevation point. During this gravity flow, the self-purification effect of the collapsed rock mass in the goaf removes large particles, fine suspended solids, and soluble organic matter from the mine water, achieving preliminary purification. Currently, the first goaf 60 preceding the ongoing mining face 50 is referred to as the mine water pretreatment goaf / underground reservoir.

[0055] Mine water, filtered from the pretreated goaf / underground reservoir, is drawn through pipeline 70 to the mine water purification system 40 for further purification. The mine water purification system 40 is equipped with corresponding pumps, control systems, pipeline 70, etc., which are standard features and will not be described in detail here. The control system of the mine water purification system 40 can be integrated with the control system of the underground water tank 20.

[0056] The usable mine water obtained after treatment and purification by the mine water purification system 40 is led out through pipeline 70 for reuse. For example, it is led through pipeline 70 to the longwall face 50 for machine cooling and dust removal, or led out through pipeline 70 to the surface for irrigation, domestic use, etc.

[0057] After deep purification treatment by the mine water purification system 40, wastewater, also known as concentrated brine, is generated. The concentrated brine is piped to the second goaf 60, located before the ongoing mining face 50, for storage. Currently, the second goaf 60, located before the ongoing mining face 50, is referred to as the concentrated brine storage goaf / underground reservoir.

[0058] In summary, the underground coal mine water treatment method provided by this invention purifies the mine water underground, starting from the No. 3 longwall face. It utilizes the first goaf in front of the ongoing longwall face for initial purification of the mine water, and the second goaf in front of the ongoing longwall face for sealing concentrated brine. During the longwall process of each longwall face, there will always be one goaf used for initial purification of the mine water and one goaf used for sealing concentrated brine. Furthermore, the goaf used for initial purification and the goaf used for sealing concentrated brine are alternated sequentially, ensuring that all goafs are usable and that all concentrated brine can be stored.

[0059] As mine water is continuously injected, the self-purification effect of the collapsed rock mass in the goaf 60, which serves as a preliminary filter, will weaken. The concentrated brine stored in the goaf 60, which serves as a sealing area, will also tend to become saturated. As underground mining activities continue, subsequent longwall faces will be successively mined out, forming new goaf 60s. The newly formed goaf 60s can be successively used as mine water pretreatment goafs / underground water reservoirs. Goaf 60s with significantly weakened self-purification effects can be used as concentrated brine sealing goafs / underground water reservoirs for permanent storage of concentrated brine.

[0060] The underground treatment method for coal mine water provided by this invention utilizes existing underground roadways and chambers to place water treatment equipment, without occupying surface land. It also utilizes the self-purification effect of collapsed rock masses in the goaf to reduce the cost of mine water treatment. The concentrated brine after deep treatment can be stored in a suitable goaf to avoid the risk of solid waste pollution caused by crystallized salt after crystallization and evaporation.

[0061] In one embodiment, such as Figure 1-2 As shown, step S04 includes:

[0062] After the formation of Goaf No. 2, and during the mining of Goaf No. 3, the mine water temporarily stored in underground water tank 20 is introduced to Goaf No. 2 through pipeline 70 for preliminary purification. The mine water after preliminary purification in Goaf No. 2 is introduced to mine water purification system 40 through pipeline 70 for further purification. The mine water obtained after purification by mine water purification system 40 is introduced for use through pipeline 70. The concentrated brine produced after treatment by mine water purification system 40 is introduced to Goaf No. 1 through pipeline.

[0063] After the No. 3 goaf is formed, and during the mining of the No. 4 mining face, the No. 1 goaf is sealed off. The mine water temporarily stored in the underground water tank 20 is piped to the No. 3 goaf for preliminary purification. The concentrated brine produced after treatment by the mine water purification system 40 is piped to the No. 2 goaf, and so on, until the No. n mining face is mined out.

[0064] In this embodiment, taking the No. 3 longwall face as an example, the mine water in the underground water tank 20 is diverted to the No. 2 goaf for preliminary purification. The No. 2 goaf is currently a mine water pretreatment goaf / underground reservoir. The mine water, after preliminary purification in the No. 2 goaf, is diverted to the mine water purification system 40 for further purification. The resulting mine water is then diverted for use via pipeline 70, and the generated concentrated brine is diverted to the No. 1 goaf via pipeline 70. The concentrated brine in the No. 1 goaf is currently sealed in the goaf / underground reservoir.

[0065] Taking the No. 4 longwall face as another example, the No. 1 goaf is sealed, the No. 2 goaf is used to seal the concentrated brine, and the No. 3 goaf is used to preliminarily purify the mine water.

[0066] Taking the No. 5 longwall face as another example, the No. 2 goaf is sealed, the No. 3 goaf is used to seal the concentrated brine, and the No. 4 goaf is used to preliminarily purify the mine water.

[0067] Taking the No. 6 longwall face as another example, the No. 3 goaf is sealed, the No. 4 goaf is used to seal the concentrated brine, and the No. 5 goaf is used to preliminarily purify the mine water.

[0068] This process continues until all mining faces n are completed.

[0069] Starting from the third longwall face, during the longwall mining process, there will always be a goaf used for preliminary purification of mine water and a goaf used for sealing concentrated brine. The goaf used for preliminary purification and the goaf used for sealing concentrated brine will also be alternated in turn, so that all goafs can be used and all concentrated brine can be stored.

[0070] As mine water is continuously injected, the self-purification effect of the collapsed rock mass in Goaf No. 2 will weaken, and the concentrated brine stored in Goaf No. 1 will approach saturation. With ongoing underground mining activities, the mining faces No. 3, 4, 5, and 6 will be successively completed, forming a new goaf 60. The newly formed goaf 60 can be successively used as a mine water pretreatment goaf / underground water reservoir. Goaf 60, whose self-purification effect has significantly weakened, can be used as a concentrated brine sealing goaf / underground water reservoir for permanent storage of concentrated brine.

[0071] In one embodiment, after the nth longwall face has been mined, the following is also included:

[0072] The mine water temporarily stored in the underground water tank 20 is led to the nth goaf through pipeline 70 for preliminary purification. The concentrated brine produced after treatment by the mine water purification system 40 is led to the n-1th goaf through pipeline 70. After the first preset time, the n-1th goaf is sealed.

[0073] In this embodiment, after the last working face 50 is mined out, concentrated brine is sealed in the second-to-last goaf 60, and the mine water stored in the underground water tank 20 is initially filtered using the last goaf 60. After the mine water stored in the underground water tank 20 is filtered, the second-to-last goaf 60 is sealed.

[0074] In one embodiment, after sealing off goaf n-1, the following is also included:

[0075] The mine water temporarily stored in the underground water tank 20 is led to the mine water purification system 40 through the pipeline 70.

[0076] The concentrated brine produced after treatment by the mine water purification system 40 is led to goaf n through pipeline 70. After a second preset time, goaf n is sealed.

[0077] In this embodiment, after sealing the second-to-last goaf 60, mine water will still collect in the underground water tank 20. At this time, the mine water in the underground water tank 20 is directly led to the mine water purification system 40. The usable mine water filtered by the mine water purification system 40 is led to the surface for reuse through the pipeline 70. The concentrated brine produced after treatment by the mine water purification system 40 is led to the last goaf 60 through the pipeline 70. After a second preset time (for example, when the mine water tank 20 no longer collects mine water or when the mining of this area is completed and the area needs to be replaced), the last goaf 60 is sealed to seal the concentrated brine underground.

[0078] In one embodiment, such as Figure 2As shown, step S04 includes: the mine water, after preliminary purification in the goaf 60, is led to the surface through pipeline 70 for reuse in production. The mine water after preliminary purification in the goaf 60 meets the requirements of some surface plants for cooling, washing, and processing, and can be directly reused. This part of the water does not need to be further purified by the mine water purification system 40.

[0079] In one embodiment, the mine water, after preliminary purification in the goaf 60, is led through pipeline 70 to a coal washing plant for coal washing and / or, after preliminary purification in the goaf 60, is led through pipeline 70 to a coal-fired power plant for machine cooling.

[0080] In one embodiment, such as Figure 2 As shown, the mine water purification system 40 includes a primary purification system 401, a secondary purification system 402, and a tertiary purification system 403.

[0081] The mine water, after preliminary purification in the goaf area 60, is led to the primary purification system 401 through pipeline 70.

[0082] The mine water, after being purified by the primary purification system 401, is led to the secondary purification system 402 through pipeline 70.

[0083] The mine water, after being purified by the secondary purification system 402, is led to the tertiary purification system 403 through pipeline 70.

[0084] The mine water, after being purified by the three-stage purification system 403, is led out to the surface through pipeline 70 for domestic use. The concentrated brine obtained after being purified by the three-stage purification system 403 is led to the second goaf 60 before the mining face 50 which is being mined and sealed.

[0085] In this embodiment, the mine water purification system 40 adopts a three-stage filtration system, which includes a primary purification system 401, a secondary purification system 402, and a tertiary purification system 403. The primary purification system 401 is an ultrafiltration purification system, the secondary purification system 402 is a reverse osmosis purification system, and the tertiary purification system 403 is a membrane distillation purification system. The primary purification system 401, the secondary purification system 402, and the tertiary purification system 403 can be built in three separate chambers.

[0086] The filtration efficiency of the primary purification system 401, the secondary purification system 402, and the tertiary purification system 403 increases sequentially, and their combined use enhances the filtration effect. Concentrated brine is separated by the tertiary purification system 403.

[0087] In one embodiment, such as Figure 2As shown, a portion of the mine water purified by the primary purification system 401 is also led through pipeline 70 to the longwall face 50 for machine cooling and dust removal, thus classifying and utilizing the mine water purified by the primary purification system 401.

[0088] In one embodiment, such as Figure 2 As shown, a portion of the mine water purified by the secondary purification system 402 is also led to an above-ground reservoir by pipeline 70 for irrigation, thus enabling the mine water purified by the secondary purification system 402 to be used in a classified manner.

[0089] In one embodiment, the mine water purified by the three-stage purification system 403 is led to a waterworks through pipeline 70 for classified utilization.

[0090] This invention proposes a graded and quality-based utilization approach for mine water after different treatment stages, based on the different requirements of production, ecology, and domestic water use above and below ground in mining areas: mine water that has undergone pretreatment and filtration in the goaf can be used by surface coal washing plants; mine water that has undergone primary treatment can be used for cooling and dust removal in underground coal mine production; mine water that has undergone secondary treatment can be used for surface ecological irrigation; and mine water that has undergone tertiary treatment can be used for domestic water use.

[0091] As needed, the above technical solutions can be combined to achieve the best technical effect.

[0092] The above are merely the principles and preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several other modifications can be made based on the principles of the present invention, and these modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for underground treatment of mine water in coal mines, characterized in that, Includes the following steps: S01: Excavation to form tunnels, underground water tanks, and vertical shafts; S02: Along the direction of the roadway extension, multiple strip-shaped longwall faces are divided in sequence and marked as longwall face No. 1, longwall face No. 2, ..., longwall face n. Correspondingly, the goaf formed after subsequent longwall mining is named goaf area No. 1, goaf area No. 2, ..., goaf area n, where n is a positive integer greater than or equal to 3. S03: Mining proceeds sequentially from mining face 1 to mining face n, and the mine water generated during the mining process is temporarily stored in an underground water tank. Among them, a mine water purification and treatment system was built in the roadway before the No. 2 longwall face was mined out; S04: During the mining process from the No. 3 longwall face to the nth longwall face: The mine water temporarily stored in the underground water tank is diverted to the first goaf area before the mining face that is being mined for preliminary purification. The preliminarily purified mine water is then transported to the mine water purification system for further purification. The mine water obtained after purification by the mine water purification system is then piped out for use. The concentrated brine produced after treatment by the mine water purification system is led to the second goaf area, located before the ongoing mining face, for storage.

2. The method for underground treatment of coal mine water according to claim 1, characterized in that, Step S04 includes: After the formation of Goaf No. 2, and during the mining of Goaf No. 3, the mine water temporarily stored in the underground water tank is piped to Goaf No. 2 for preliminary purification. The mine water after preliminary purification in Goaf No. 2 is piped to the mine water purification system for further purification. The mine water obtained after purification by the mine water purification system is piped out for use. The concentrated brine produced after purification by the mine water purification system is piped to Goaf No.

1. After the No. 3 goaf is formed, and during the mining of the No. 4 mining face, the No. 1 goaf is sealed off. The mine water temporarily stored in the underground water tank is piped to the No. 3 goaf for preliminary purification. The concentrated brine produced after treatment by the mine water purification system is piped to the No. 2 goaf, and so on, until the No. n mining face is mined out.

3. The method for underground treatment of coal mine water according to claim 2, characterized in that, After the nth longwall face is completed, the following is also included: The mine water temporarily stored in the underground water tank is piped to the nth goaf for preliminary purification. The concentrated brine produced after treatment by the mine water purification system is piped to the n-1th goaf. After the first preset time, the n-1th goaf is sealed.

4. The method for underground treatment of coal mine water according to claim 3, characterized in that, After sealing off goaf n-1, the following is also included: Mine water temporarily stored in the underground water tank is piped to the mine water purification system; The concentrated brine produced after treatment by the mine water purification system is piped to goaf area n. After a second preset time, goaf area n is sealed off.

5. The method for underground treatment of mine water in coal mines according to any one of claims 1-4, characterized in that, Step S04 includes: the mine water, after preliminary purification in the goaf, is piped to the surface for reuse in production.

6. The method for underground treatment of coal mine water according to claim 5, characterized in that, Mine water, after preliminary purification in the goaf, is piped to a coal washing plant for coal washing and / or to a coal-fired power plant for machine cooling.

7. The method for underground treatment of mine water in coal mines according to any one of claims 1-4, characterized in that, The mine water purification system includes a primary purification system, a secondary purification system, and a tertiary purification system. The mine water, after initial purification in the goaf area, is piped to the primary purification system. Mine water that has been purified by the primary purification system is piped to the secondary purification system. Mine water that has been purified by the secondary purification system is piped to the tertiary purification system. The mine water, after being purified by the three-stage purification system, is piped to the surface for domestic use. The concentrated brine obtained after the three-stage purification system is then sealed in the second goaf area before the mining face that is currently being mined.

8. The method for underground treatment of coal mine water according to claim 7, characterized in that, Part of the mine water, after being purified by the primary purification system, is also piped to the longwall face where it is being mined, for use in machine cooling and dust removal.

9. The method for underground treatment of coal mine water according to claim 7, characterized in that, A portion of the mine water, after being purified by the secondary purification system, is piped to an above-ground reservoir for irrigation.

10. The method for underground treatment of coal mine water according to claim 7, characterized in that, The mine water, after being purified by a three-stage purification system, is piped to a waterworks.

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