Underground treatment method for coal mine water

Abstract

The invention discloses an underground treatment method for coal mine water, which comprises the following steps of: performing underground purification treatment on the mine water, performing preliminary purification on the mine water by utilizing a first goaf in front of a stoping working face in stoping, and sealing and storing strong brine by utilizing a second goaf in front of the stoping working face in stoping; water treatment equipment is placed in an underground existing roadway chamber, the ground land is not occupied, the mine water treatment cost is reduced through the self-purification effect of the caving rock mass of the goaf, strong brine obtained after deep treatment can be stored in the proper goaf, and the solid waste pollution risk caused by crystallized salt generated after crystallization and evaporation is avoided.

Description

Technical Field

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

[0002] Mine water is produced during the coal mining process. After treatment, most of the mine water can be reused, and the wastewater (concentrated brine) produced needs to be specially treated or sealed.

[0003] Traditional mine water treatment technology usually adopts the above-ground treatment method, which is treated through conventional ground water treatment facilities. Some mine water meets the reuse standards and is returned to the underground for reuse. The ground treatment method has the disadvantages of large infrastructure investment, high mine water lifting and operation costs, and large land area. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a novel underground treatment method for coal mine water, which purifies the mine water underground, utilizes the first goaf in front of the mining work being recovered to preliminarily purify the mine water, utilizes the second goaf in front of the mining work being recovered to seal the concentrated brine, utilizes the existing tunnels and chambers underground to place water treatment equipment without occupying the ground land, utilizes the self-purification effect of the rock mass falling in the goaf to reduce the mine water treatment cost, and the deeply treated concentrated brine can be stored in a suitable goaf to avoid the risk of solid waste pollution caused by the crystallized salt produced after crystallization and evaporation.

[0005] The technical solution of the present invention provides a method for treating coal mine water underground, comprising the following steps:

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

[0007] S02: along the direction of the tunnel extension, a plurality of strip-type mining working faces are divided in sequence and marked as No. 1 mining working face, No. 2 mining working face... No. n mining working face in sequence. Accordingly, the goafs formed after subsequent mining are named No. 1 goaf, No. 2 goaf... No. n goaf in sequence, where n is a positive integer greater than or equal to 3;

[0008] S03: Mining is performed in sequence from No. 1 mining face to No. n mining face, and the mine water generated during the mining of each mining face is temporarily stored in an underground water tank;

[0009] Among them, before the No. 2 mining face was mined, a mine water purification system was built in the tunnel;

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

[0011] The mine water temporarily stored in the underground water tank is led to the first goaf before the mining face for preliminary purification, and the initially purified mine water is transported to the mine water purification treatment system for purification treatment. The mine water obtained after purification by the mine water purification treatment system is led out for use through pipelines;

[0012] The concentrated brine produced after treatment by the mine water purification system is led to the second goaf before the mining face being mined and sealed.

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

[0014] After the formation of goaf No. 2 and when mining the goaf No. 3, the mine water temporarily stored in the underground water tank is led to goaf No. 2 through a pipeline for preliminary purification. The mine water after preliminary purification in goaf No. 2 is led to the mine water purification treatment system through a pipeline for purification treatment. The mine water obtained after purification by the mine water purification treatment system is led out through a pipeline for use. The concentrated brine produced after treatment by the mine water purification treatment system is led to goaf No. 1 through a pipeline;

[0015] After the formation of goaf No. 3 and when mining working face No. 4 is being mined, goaf No. 1 is sealed, and the mine water temporarily stored in the underground water tank is led to goaf No. 3 through a pipe for preliminary purification. The concentrated brine produced after treatment by the mine water purification system is led to goaf No. 2 through a pipe, and so on, until mining working face No. n is mined.

[0016] In one of the optional technical solutions, after mining the No. n mining face, the following steps are also included:

[0017] The mine water temporarily stored in the underground water tank is led to the No. n goaf through a pipe for preliminary purification. The concentrated brine produced after treatment by the mine water purification system is led to the No. n-1 goaf through a pipe. After the first preset time, the No. n-1 goaf is sealed.

[0018] In one of the optional technical solutions, after sealing the n-1 goaf, it also includes:

[0019] The mine water temporarily stored in the underground water tank is led to the mine water purification system through pipelines;

[0020] The concentrated brine produced after being treated by the mine water purification system is led to goaf No. n through a pipeline, and after a second preset time, goaf No. n is sealed.

[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 production reuse.

[0022] In one of the optional technical solutions, the mine water that has been initially purified in the goaf is led through a pipeline to a coal washing plant for use in coal washing; and / or, the mine water that has been initially purified in the goaf is led through a pipeline to a coal-fired power plant for use in 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 preliminary purification in the goaf is led to the primary purification treatment system through pipelines;

[0025] The mine water purified by the primary purification system is led to the secondary purification system through pipelines;

[0026] The mine water purified by the secondary purification system is led to the tertiary purification system through pipelines;

[0027] The mine water purified by the three-stage purification system is led out to the surface through pipes for domestic use, and the concentrated brine obtained after purification by the three-stage purification system is led to the second goaf before the mining face being mined and sealed.

[0028] In one of the optional technical solutions, part of the mine water purified by the primary purification system is also led through a pipeline to the mining face for machine cooling and dust removal.

[0029] In one of the optional technical solutions, part of the mine water purified by the secondary purification system is also led to an above-ground reservoir through a pipeline for irrigation.

[0030] In one of the optional technical solutions, the mine water purified by the three-stage purification system is led to the water plant through a pipeline.

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

[0032] The underground treatment method of coal mine water provided by the present invention purifies the mine water underground, starts from the No. 3 mining face, uses the first goaf in front of the mining face being mined to preliminarily purify the mine water, and uses the second goaf in front of the mining face being mined to seal the concentrated brine. During the mining process of each mining face, there is always a goaf for preliminarily purifying the mine water, and there is always a goaf for sealing the concentrated brine, and the goaf used for preliminarily purifying and the goaf used for sealing the concentrated brine are also replaced in sequence, so that all the goafs are available, and it can be ensured that all the concentrated brine can be stored.

[0033] The underground treatment method of coal mine water provided by the present invention utilizes the existing tunnels and chambers underground to place water treatment equipment without occupying ground land, utilizes the self-purification effect of the fallen rock mass in the goaf area to reduce the cost of mine water treatment, and the concentrated brine after deep treatment can be stored in a suitable goaf area to avoid the risk of solid waste pollution caused by the crystallized salt produced after crystallization and evaporation. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0036] Figure 2 This is a schematic diagram of using goaf No. 1 to store concentrated brine and using goaf No. 2 for preliminary filtration when mining the No. 3 mining face. DETAILED DESCRIPTION

[0037] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. The same components are represented by the same reference numerals. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the accompanying drawings, and the words "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 underground treatment method for coal mine water provided by an embodiment of the present invention comprises the following steps:

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

[0040] S02: Along the direction in which the tunnel extends, a plurality of strip-type mining working faces 50 are divided in sequence and marked as mining working face No. 1, mining working face No. 2...mining working face No. n in sequence. Accordingly, the goafs 60 formed after subsequent mining are named goaf No. 1, goaf No. 2...goaf No. n in sequence, where n is a positive integer greater than or equal to 3.

[0041] S03: Mining is performed in sequence from No. 1 mining face to No. n mining face. The mine water generated during the mining of each mining face 50 is temporarily stored in the underground water tank 20 .

[0042] Among them, before the No. 2 mining working face is mined, a mine water purification system 40 is built in the tunnel 10.

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

[0044] The mine water temporarily stored in the underground water tank 20 is led to the first goaf 60 in front of the mining face 50 being mined for preliminary purification, and the initially purified mine water is transported to the mine water purification treatment system 40 for purification. The mine water obtained after purification by the mine water purification treatment system 40 is led out for use through a pipeline.

[0045] The concentrated brine produced after being treated by the mine water purification system 40 is led to a second goaf 60 located before the mining working face 50 being mined and sealed.

[0046] The underground treatment method of coal mine water provided by the invention can treat, classify and utilize the coal mine water while mining.

[0047] Specifically, the steps include:

[0048] Step 1: Initial preparation work, excavation to form a tunnel 10, an underground water tank 20 and a vertical shaft 30. The underground water tank 20 is an underground chamber, and multiple underground chambers can be used to construct multiple underground water tanks 20 as needed. A water system will be built outside the underground water tank 20, including a water pump, a control system, a pipeline 70, etc., which is used to lead the mine water or production wastewater generated by the mining face 50 to the underground water tank 20 for temporary storage, and also to transport the mine water in the underground water tank 20 to a goaf 60 for preliminary purification using the falling rock mass. The water pump, control system, pipeline 70, etc. are conventionally arranged and will not be repeated here.

[0049] The vertical shaft 30 connects the ground surface with the tunnel 10 and is used for arranging the pipeline 70 .

[0050] Step 2: Preparatory work before mining. Coal mining adopts a strip mining method. Along the length direction of the tunnel 10, multiple interval-arranged mining faces 50 are divided in sequence. The mining direction of the mining face 50 is roughly perpendicular to the tunnel 10. For the convenience of description, along the direction from one end of the tunnel 10 to the vertical shaft 30, multiple mining faces 50 are marked as No. 1 mining face, No. 2 mining face... No. n mining face, which is a positive integer greater than or equal to 3. Also for the convenience of description, according to the sequence number of the mining face 50, the goaf 60 formed after subsequent mining are named No. 1 goaf, No. 2 goaf... No. n goaf. After each goaf 60 is formed, the opening connected to the tunnel 10 is blocked to form an underground reservoir for filtering mine water and sealing the underground reservoir. In the subsequent description, the mined-out areas used for filtration and sealing are all underground reservoirs, that is, mined-out area No. 1, mined-out area No. 2...mined-out area No. n correspond to underground reservoir No. 1, underground reservoir No. 2...underground reservoir No. n.

[0051] Step 3: The mining face 50 starts mining, specifically in the order from mining face No. 1 to mining face No. n. When mining each mining face 50, the pipe 70 of the underground water tank 20 is connected to the water outlet (e.g., water storage ditch / trough) of each mining face 50, so as to lead the mine water generated in the process of mining each mining face 50 to the underground water tank 20, and temporarily store it in the underground water tank 20. For example, the mine water generated when mining the mining face No. 1 is temporarily stored in one or more underground water tanks 20, the mine water generated when mining the mining face No. 2 is also temporarily stored in one or more underground water tanks 20, and the mine water generated when mining the mining faces No. 3, No. 4...n in the subsequent mining is first temporarily stored in one or more underground water tanks 20. Starting from the No. 3 mining face, the mine water in the underground water tank 20 begins to be transported to the goaf 60, and the mine water is preliminarily purified through the goaf 60.

[0052] Before mining the No. 2 mining face, it is necessary to build a mine water purification system 40 in the tunnel 10. The mine water purification system 40 is built in one or more chambers on one side of the tunnel 10. The mine water purification system 40 is used to purify the mine water that has been initially purified in the goaf 60 again, and can obtain mine water that can be reused and wastewater (concentrated brine) that needs to be sealed. The mine water purification system 40 can adopt a combination of an ultrafiltration purification system, a reverse osmosis purification system, and a membrane distillation purification system.

[0053] Step 4: In the process of mining from No. 3 mining face to No. n mining face, the mine water purification treatment method is as follows:

[0054] Taking the mining face 50 being mined as a reference, the water delivery pipe 70 of the underground water tank 20 is connected to the first goaf 60 with a higher elevation before the mining face 50 being mined. The mine water injected into the goaf flows to the lower elevation under the action of its own weight. During the self-flow process, the large particles, fine suspended matter and soluble organic matter in the mine water are removed by the self-purification effect of the fallen rock mass in the goaf, thereby achieving preliminary purification of the mine water. At present, the first goaf 60 before the mining face 50 being mined is called the mine water pretreatment goaf / underground reservoir.

[0055] The mine water filtered by the mine water pretreatment goaf / underground reservoir is led to the mine water purification system 40 for purification through the pipeline 70. The mine water purification system 40 will be equipped with corresponding water pumps, control systems, pipelines 70, etc., which are conventional settings and will not be repeated 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 being treated and purified by the mine water purification system 40 is led out through the pipeline 70 for reuse. For example, it is led to the mining face 50 through the pipeline 70 for machine cooling and dust removal, and is led out through the pipeline 70 through the vertical shaft 30 for surface irrigation, daily use, etc.

[0057] After deep purification by the mine water purification system 40, wastewater is generated, also called concentrated brine. The concentrated brine is led to the second goaf 60 before the mining working face 50 through a pipeline for sealing. Currently, the second goaf 60 before the mining working face 50 is called the concentrated brine sealing goaf / underground reservoir.

[0058] To sum up, the underground treatment method of coal mine water provided by the present invention purifies the mine water underground, starting from the No. 3 mining face, and uses the first goaf in front of the mining face being mined to preliminarily purify the mine water, and uses the second goaf in front of the mining face being mined to seal the concentrated brine. During the mining process of each mining face, there is always a goaf for preliminarily purifying the mine water, and there is always a goaf for sealing the concentrated brine, and the goaf used for preliminary purification and the goaf used for sealing the concentrated brine are also replaced in sequence, so that all goafs are available, ensuring that all the concentrated brine can be stored.

[0059] With the continuous injection of mine water, the self-purification effect of the caving rock mass in the goaf 60 with the initial filtering effect will weaken, and the concentrated brine stored in the goaf 60 with the sealing effect will also tend to be saturated. As the underground mining activities proceed, the subsequent recovery working faces will be recovered one after another, forming new goaf 60. The newly formed goaf 60 can be used as mine water pretreatment goaf / underground reservoir. The goaf 60 whose self-purification effect has been significantly weakened can be used as a concentrated brine sealing goaf / underground reservoir for permanent storage of concentrated brine.

[0060] The underground treatment method of coal mine water provided by the present invention utilizes the existing tunnels and chambers underground to place water treatment equipment without occupying ground land, utilizes the self-purification effect of the fallen rock mass in the goaf area to reduce the cost of mine water treatment, and the concentrated brine after deep treatment can be stored in a suitable goaf area to avoid the risk of solid waste pollution caused by the crystallized salt produced after crystallization and evaporation.

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

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

[0063] After the formation of goaf No. 3 and when mining working face No. 4 is being mined, goaf No. 1 is sealed, and the mine water temporarily stored in the underground water tank 20 is led to goaf No. 3 through a pipeline for preliminary purification. The concentrated brine produced after treatment by the mine water purification treatment system 40 is led to goaf No. 2 through a pipeline, and so on, until mining working face No. n is mined.

[0064] In this embodiment, taking the mining face No. 3 as an example, the mine water in the underground water tank 20 is led to the goaf No. 2 for preliminary purification. The current goaf No. 2 is the mine water pretreatment goaf / underground reservoir. The mine water after preliminary purification in goaf No. 2 is led to the mine water purification system 40 for further purification. The obtained mine water is led out through the pipeline 70 for use, and the generated concentrated brine is led to the goaf No. 1 through the pipeline 70. The concentrated brine in the current goaf No. 1 is sealed in the goaf / underground reservoir.

[0065] Taking the No. 4 mining face as an 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 mining face as an 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 mining face as an example, the No. 3 goaf will be sealed, the No. 4 goaf will be used to seal the concentrated brine, and the No. 5 goaf will be used to preliminarily purify the mine water.

[0068] And so on, until the nth mining face is mined.

[0069] Starting from the third mining face, during the mining process of each mining face, there will always be a goaf area used for preliminary purification of mine water, and there will always be a goaf area used to seal the concentrated brine, and the goaf areas used for preliminary purification and the goaf areas used to seal the concentrated brine will also be replaced in sequence, so that all the goaf areas can be utilized, ensuring that all the concentrated brine can be stored.

[0070] With the continuous injection of mine water, the self-purification effect of the caving rock mass in the No. 2 goaf will weaken, and the concentrated brine stored in the No. 1 goaf will also tend to be saturated. As the underground mining activities proceed, the mining working faces of No. 3, No. 4, No. 5, and No. 6 will be successively completed, thus forming new goafs 60. The newly formed goafs 60 can be successively used as mine water pretreatment goafs / underground reservoirs. The goafs 60 whose self-purification effect has been significantly weakened can be used as concentrated brine sealing goafs / underground reservoirs for permanent storage of concentrated brine.

[0071] In one embodiment, after mining the nth mining face, the method further includes:

[0072] The mine water temporarily stored in the underground water tank 20 is led to the goaf No. n through the pipeline 70 for preliminary purification. The concentrated brine produced after treatment by the mine water purification system 40 is led to the goaf No. n-1 through the pipeline 70. After the first preset time, the goaf No. n-1 is sealed.

[0073] In this embodiment, after the last mining face 50 is mined, the second to last goaf 60 is used to seal the concentrated brine, and the last goaf 60 is used to preliminarily filter the mine water stored in the underground water tank 20. After the filtration process of the mine water stored in the underground water tank 20 is completed, the second to last goaf 60 is sealed.

[0074] In one embodiment, after sealing the n-1 goaf, the method further includes:

[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 being processed by the mine water purification system 40 is led to the goaf No. n through the pipeline 70, and after the second preset time, the goaf No. n is sealed.

[0077] In the present embodiment, after the second-to-last goaf 60 is sealed, there will still be mine water collected 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 treatment system 40. The usable mine water filtered by the mine water purification treatment system 40 is led to the ground through a pipe 70 for reuse. The concentrated brine produced after treatment by the mine water purification treatment system 40 is led to the last goaf 60 through a pipe 70. After a second preset time (for example, mine water is no longer gathered in the underground water tank 20 or the mining of the 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, if Figure 2As shown, step S04 includes: the mine water after preliminary purification in the goaf 60 is led to the surface through the pipeline 70 for production reuse. The mine water after preliminary purification in the goaf 60 meets the requirements of cooling, washing and selection of some factories on the surface, and can be directly reused. This part of water does not need to be purified by the mine water purification system 40.

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

[0080] In one embodiment, if 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 that has been preliminarily purified in the goaf 60 is led to the primary purification system 401 through the pipeline 70 .

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

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

[0084] The mine water purified by the tertiary purification system 403 is led to the surface through a pipeline 70 for domestic use, and the concentrated brine obtained after purification by the tertiary purification system 403 is led to the second goaf 60 before the mining working face 50 being mined for storage.

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

[0086] The filtering effects of the primary purification system 401 , the secondary purification system 402 and the tertiary purification system 403 are improved in sequence, and the combined use improves the filtering effect. The concentrated brine is separated by the tertiary purification system 403 .

[0087] In one embodiment, if Figure 2As shown, part of the mine water purified by the primary purification system 401 is also led to the mining face 50 by the pipeline 70 for machine cooling and dust removal, and the mine water purified by the primary purification system 401 is classified for utilization.

[0088] In one embodiment, if Figure 2 As shown, part of the mine water purified by the secondary purification system 402 is also led to the ground reservoir through the pipeline 70 for irrigation, and the mine water purified by the secondary purification system 402 is classified and utilized.

[0089] In one embodiment, the mine water purified by the three-stage purification system 403 is led to the water plant through the pipeline 70, and the mine water purified by the three-stage purification system 403 is classified and utilized.

[0090] The present invention proposes a graded and quality-based utilization approach for mine water after different treatment stages according to different requirements for production, ecology and domestic water above and below the ground in a mining area: the mine water after pre-treatment and filtration in the goaf can be used in a ground coal washing plant; the mine water after primary treatment can be used for cooling and dust removal in underground coal mine production; the mine water after secondary treatment can be used for ground ecological irrigation; and the mine water after tertiary treatment can be used for domestic water.

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

[0092] The above are only 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, which should also be considered as the protection scope of the present invention.

Claims

1. A method for treating coal mine water underground, characterized in that: The steps include: S01: Excavation to form tunnels, underground water tanks and vertical shafts; S02: along the direction of the tunnel extension, a plurality of strip-type mining working faces are divided in sequence and marked as No. 1 mining working face, No. 2 mining working face... No. n mining working face in sequence. Accordingly, the goafs formed after subsequent mining are named No. 1 goaf, No. 2 goaf... No. n goaf in sequence, where n is a positive integer greater than or equal to 3; S03: Mining is performed in sequence from No. 1 mining face to No. n mining face, and the mine water generated during the mining of each mining face is temporarily stored in an underground water tank; Among them, before the No. 2 mining face was mined, a mine water purification system was built in the tunnel; S04: During the mining process from No. 3 mining face to No. n mining face: The mine water temporarily stored in the underground water tank is led to the first goaf before the mining face for preliminary purification, and the initially purified mine water is transported to the mine water purification treatment system for purification treatment. The mine water obtained after purification by the mine water purification treatment system is led out for use through pipelines; The concentrated brine produced after treatment by the mine water purification system is led to the second goaf before the mining face being mined and sealed.

2. The underground treatment method for coal mine water according to claim 1, characterized in that: The step S04 includes: After the formation of goaf No. 2 and when mining the goaf No. 3, the mine water temporarily stored in the underground water tank is led to goaf No. 2 through a pipeline for preliminary purification. The mine water after preliminary purification in goaf No. 2 is led to the mine water purification treatment system through a pipeline for purification treatment. The mine water obtained after purification by the mine water purification treatment system is led out through a pipeline for use. The concentrated brine produced after treatment by the mine water purification treatment system is led to goaf No. 1 through a pipeline; After the formation of goaf No. 3 and when mining working face No. 4 is being mined, goaf No. 1 is sealed, and the mine water temporarily stored in the underground water tank is led to goaf No. 3 through a pipe for preliminary purification. The concentrated brine produced after treatment by the mine water purification system is led to goaf No. 2 through a pipe, and so on, until mining working face No. n is mined.

3. The underground treatment method for coal mine water according to claim 2, characterized in that: After the mining of No. n mining face, it also includes: The mine water temporarily stored in the underground water tank is led to the No. n goaf through a pipe for preliminary purification. The concentrated brine produced after treatment by the mine water purification system is led to the No. n-1 goaf through a pipe. After the first preset time, the No. n-1 goaf is sealed.

4. The underground treatment method for coal mine water according to claim 3, characterized in that: After sealing the n-1 goaf, it also includes: The mine water temporarily stored in the underground water tank is led to the mine water purification system through pipelines; The concentrated brine produced after being treated by the mine water purification system is led to goaf No. n through a pipeline, and after a second preset time, goaf No. n is sealed.

5. The underground treatment method for coal mine water according to any one of claims 1 to 4, characterized in that: The step S04 includes: the mine water after preliminary purification in the goaf is led to the surface through a pipeline for production reuse.

6. The underground treatment method for coal mine water according to claim 5, characterized in that: The mine water that has been initially purified in the goaf is led to the coal washing plant through pipelines for use in coal washing; and / or, the mine water that has been initially purified in the goaf is led to the coal-fired power plant through pipelines for use in machine cooling.

7. The underground treatment method for coal mine water according to any one of claims 1 to 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 preliminary purification in the goaf is led to the primary purification treatment system through pipelines; The mine water purified by the primary purification system is led to the secondary purification system through pipelines; The mine water purified by the secondary purification system is led to the tertiary purification system through pipelines; The mine water purified by the three-stage purification system is led out to the surface through pipes for domestic use, and the concentrated brine obtained after purification by the three-stage purification system is led to the second goaf before the mining face being mined and sealed.

8. The underground treatment method for coal mine water according to claim 7, characterized in that: Part of the mine water purified by the primary purification system is also led through pipelines to the mining face for machine cooling and dust removal.

9. The underground treatment method for coal mine water according to claim 7, characterized in that: Part of the mine water purified by the secondary purification system is also led through pipes to above-ground reservoirs for irrigation.

10. The underground treatment method for coal mine water according to claim 7, characterized in that: The mine water purified by the three-stage purification system is led to the water plant through pipes.

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