Sustainable low-cost filling process for underground coal mine

Abstract

The invention relates to an underground coal mine sustainable low-cost filling process, which comprises the following steps that gangue powder and water are uniformly added from one side of a stirrer according to a preset proportion, and after full stirring, gangue slurry enters a material suction opening of a stirring pump from the other side of the stirrer; waste rock slurry in the stirring barrel enters a material suction opening of a filling pump, the slurry in the material suction opening is pumped to a filling position in a pressurization mode, and filling is conducted through pre-constructed high-position filling drill holes, middle-position filling drill holes and low-position filling drill holes; the gangue slurry enters the gap space of the goaf after entering the preformed hole, firstly, paving type inflow is started, the gangue slurry is diffused to the gap of the goaf by means of gravity, and after the gap in the lower portion of the goaf is filled, stacking type filling is started along the slope face of the slurry on the lower layer according to the gravity flow gradient. According to the method, the separation layer and the goaf are fully utilized for safe and economical full-space filling, that is, coal gangue slurry is injected into a key layer, a goaf caving zone and a fissure zone through directional drilling underground, so that the filling cost is reduced, and the purpose of sustainable filling is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of coal mine backfilling, and in particular to a sustainable low-cost filling process in underground coal mines. Background Art

[0002] Backfill mining is to use the gangue, sand, gravel and other materials in the mine or on the ground to fill the goaf in order to control the movement of rock formations and surface subsidence. According to the filling method, it can be divided into hydraulic filling, wind filling, gangue self-flowing filling, mechanical filling, etc.; according to the filling material used, it can be divided into non-cemented filling method and cemented filling method.

[0003] Mine filling technology has a history of hundreds of years. Since the early 20th century, Australian metal mines have begun to use waste rock filling in a planned manner. By the 1990s, mine filling mining has gone through roughly four stages, including mine fertilizer dry filling for the purpose of waste treatment, water sand filling, tailings filling, high-concentration filling technology, paste filling, block stone mortar filling and full tailings filling.

[0004] In the initial stage, backfill mining technology was mainly used in non-ferrous or ferrous metal mining. Due to the complexity of coal mining, high backfilling costs, and low coal prices, these backfilling mining technologies have not been promoted and applied in coal mines. In recent years, due to the rapid development of the national economy and the development of the coal industry itself, the development of sustainable low-cost backfilling technology in coal mining has become a trend. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a sustainable and low-cost filling process in underground coal mines to solve the problems raised in the above-mentioned background technology.

[0006] In order to achieve the above purpose, the technical solutions adopted are as follows:

[0007] A sustainable and low-cost filling process for underground coal mines, comprising the following steps:

[0008] S1: The gangue after intelligent dry separation enters the jaw crusher through the belt conveyor and scraper, and is crushed to ≤40mm and enters the rod mill;

[0009] S2: The slurry from the rod mill is transported to the feed port of the ball mill through a slurry pump, and the slurry is milled to 100 mesh in the ball mill and enters the stirring tank;

[0010] S3: The pulping water is pumped from the water tank through the pipeline and metered into the mixer by the solenoid valve or the electric control valve for pulping;

[0011] S4: Gangue powder and water are evenly added from one side of the mixer according to the preset ratio. After being fully mixed, the gangue slurry enters the suction port of the mixing pump from the other side of the mixer;

[0012] S5: The gangue slurry in the mixing barrel enters the suction port of the filling pump, and the slurry in the suction port is pumped to the filling position by pressurizing, and the filling is carried out using the pre-constructed high, medium and low filling holes;

[0013] S6: After the gangue slurry enters the reserved hole, it enters the void space of the goaf and begins to flow in in a spreading manner, using gravity to diffuse to the void space of the goaf. After the void space at the bottom of the goaf is filled, it begins to be filled in a overlapping manner along the slope of the lower slurry according to the self-flowing slope;

[0014] S7: One week after filling, the filling slurry begins to seep water until the amount of water seepage reaches the daily filling water consumption.

[0015] Preferably, in step S1, an intelligent dry sorting machine is used to adopt an intelligent recognition method, and an analysis model suitable for different coal characteristics is established. Through big data analysis, coal and gangue are digitally identified, and the gangue is discharged through a high-pressure wind-beating gangue discharge system.

[0016] Preferably, the intelligent recognition method includes a photoelectric recognition method that combines X-ray recognition and image recognition.

[0017] Preferably, step S5 is divided into high-position grouting, adjacent-position grouting and low-position grouting according to the position of the filling space;

[0018] High-position grouting utilizes the formed separation zone, fracture zone, caving zone, "O"-shaped ring separation zone, fracture space and goaf space, and uses high-pressure filling to inject gangue slurry into the full space of the closed goaf for treatment. High-position filling is divided into separation layer grouting and full space filling;

[0019] Adjacent grouting is based on the analysis of the caving space. It is planned to conduct drilling grouting in the goaf of the working face. The grouting layer is the collapse zone of the mined coal seam, and the grouting area is within the "O"-shaped circle. The drilling site is arranged in the adjacent working drift, and it passes through the isolation coal pillar obliquely upward to enter the collapse zone. The gangue slurry adjacent filling technology refers to crushing and grinding the gangue into powder of a certain particle size at a suitable position on the ground or underground, mixing the finished gangue powder with a certain proportion of water to form slurry, and then using a grouting pump to transport the slurry through the ground conveying pipeline and the underground conveying pipeline to the workable space adjacent to the goaf. Finally, the grouting borehole is used to fill the slurry into the residual space remaining after the overburden collapse.

[0020] Low-position grouting utilizes the space of the original mining tunnel for filling, and grouting pipes are arranged in the drifts on both sides. During the continuous mining process of the working face, the grouting filling pipes are arranged in the two mining tunnels in advance to realize hanging pipe filling.

[0021] The beneficial effects of the present invention are:

[0022] The present invention selects high-position, middle-position and low-position filling methods, and makes full use of the safe and economical full-space filling of the strata and goafs, that is, injecting filling coal gangue slurry into the key layers, goaf collapse zones and fracture zones through directional drilling underground, thereby reducing the filling cost and achieving the purpose of sustainable filling. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail with reference to the embodiments below.

[0024] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present application.

[0025] A sustainable and low-cost filling process for underground coal mines, comprising the following steps:

[0026] S1: The gangue after intelligent dry separation enters the jaw crusher through the belt conveyor and scraper, and is crushed to ≤40mm and enters the rod mill;

[0027] S2: The slurry from the rod mill is transported to the feed port of the ball mill through a slurry pump, and the slurry is milled to 100 mesh in the ball mill and enters the stirring tank;

[0028] S3: The pulping water is pumped from the water tank through the pipeline and metered into the mixer by the solenoid valve or the electric control valve for pulping;

[0029] S4: Gangue powder and water are evenly added from one side of the mixer according to the preset ratio. After being fully mixed, the gangue slurry enters the suction port of the mixing pump from the other side of the mixer;

[0030] S5: The gangue slurry in the mixing barrel enters the suction port of the filling pump, and the slurry in the suction port is pumped to the filling position by pressurizing, and the filling is carried out using the pre-constructed high, medium and low filling holes;

[0031] S6: After the gangue slurry enters the reserved hole, it enters the void space of the goaf and begins to flow in in a spreading manner, using gravity to diffuse to the void space of the goaf. After the void space at the bottom of the goaf is filled, it begins to be filled in a overlapping manner along the slope of the lower slurry according to the self-flowing slope;

[0032] S7: One week after filling, the filling slurry begins to seep water until the amount of water seepage reaches the daily filling water consumption.

[0033] In step S1, an intelligent dry sorting machine adopts an intelligent recognition method to establish an analysis model suitable for different coal characteristics, and digitally identify coal and gangue through big data analysis, and discharge the gangue through a gangue discharge system struck by high-pressure wind; wherein, the intelligent recognition method includes a photoelectric recognition method combining X-ray recognition and image recognition.

[0034] Step S5, dividing into high-position grouting, adjacent-position grouting and low-position grouting according to the position of the filling space;

[0035] High-position grouting utilizes the formed separation zone, fracture zone, caving zone, "O"-shaped ring separation zone, fracture space and goaf space, and uses high-pressure filling to inject gangue slurry into the full space of the closed goaf for treatment. High-position filling is divided into separation layer grouting and full space filling;

[0036] Based on the analysis of the caving space, it is planned to conduct drilling and grouting in the goaf of the working face. The grouting layer is the collapse zone of the mined coal seam, and the grouting area is within the "O"-shaped circle (with well-developed voids and good connectivity). The drilling site is arranged in a drift adjacent to the work, and passes through the isolation coal pillar obliquely upward to enter the caving zone; the gangue slurry adjacent filling technology refers to crushing and grinding the gangue into a powder of a certain particle size at a suitable location on the ground or underground, mixing the finished gangue powder with a certain proportion of water to form a slurry, and then using a grouting pump to transport the slurry through the ground and underground pipelines to the workable space adjacent to the goaf, and finally using the grouting borehole to fill the slurry into the residual space remaining after the overburden collapse;

[0037] Low-position grouting uses the space of the original mining tunnel for filling, and grouting pipes are arranged in the drifts on both sides. In the process of continuous mining at the working face, the grouting filling pipes are arranged in the two mining tunnels in advance to realize hanging pipe filling. Since the low-position grouting pipes of the working face need to grout the goaf of the lagging working face, their location selection must ensure that they are not compacted by the collapsed roof and are convenient for grouting and filling without affecting the normal production of the working face.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A sustainable low-cost filling process for underground coal mines, characterized in that: The following steps are involved: S1: The gangue after intelligent dry separation enters the jaw crusher through the belt conveyor and scraper, and is crushed to ≤40mm and enters the rod mill; S2: The slurry from the rod mill is transported to the feed port of the ball mill through a slurry pump, and the slurry is milled to 100 mesh in the ball mill and enters the stirring tank; S3: The pulping water is pumped from the water tank through the pipeline and metered into the mixer by the solenoid valve or the electric control valve for pulping; S4: Gangue powder and water are evenly added from one side of the mixer according to the preset ratio. After being fully mixed, the gangue slurry enters the suction port of the mixing pump from the other side of the mixer; S5: The gangue slurry in the mixing barrel enters the suction port of the filling pump, and the slurry in the suction port is pumped to the filling position by pressurizing, and the filling is carried out using the pre-constructed high, medium and low filling holes; S6: After the gangue slurry enters the reserved hole, it enters the void space of the goaf and begins to flow in in a spreading manner, using gravity to diffuse to the void space of the goaf. After the void space at the bottom of the goaf is filled, it begins to be filled in a overlapping manner along the slope of the lower slurry according to the self-flowing slope; S7: One week after filling, the filling slurry begins to seep water until the amount of water seepage reaches the daily filling water consumption.

2. A sustainable low-cost filling process for underground coal mines according to claim 1, characterized in that: In step S1, an intelligent dry sorting machine adopts an intelligent recognition method to establish an analysis model suitable for different coal characteristics, and through big data analysis, the coal and gangue are digitally identified, and the gangue is discharged through a high-pressure wind-beating gangue discharge system.

3. A sustainable low-cost filling process for underground coal mines according to claim 2, characterized in that: Intelligent recognition methods include photoelectric recognition methods that combine X-ray recognition and image recognition.

4. A sustainable low-cost filling process for underground coal mines according to claim 1, characterized in that: Step S5, dividing into high-position grouting, adjacent-position grouting and low-position grouting according to the position of the filling space; High-position grouting utilizes the formed separation zone, fracture zone, caving zone, "O"-shaped ring separation zone, fracture space and goaf space, and uses high-pressure filling to inject gangue slurry into the full space of the closed goaf for treatment. High-position filling is divided into separation layer grouting and full space filling; Adjacent grouting According to the analysis of the caving space, drilling and grouting are planned to be carried out in the goaf of the working face. The grouting layer is the collapse zone of the mined coal seam, and the grouting area is within the "O"-shaped circle; the drilling site is arranged in the adjacent working drift, obliquely passing through the isolation coal pillar to enter the caving zone; the gangue slurry adjacent filling technology refers to crushing and grinding the coal gangue into powder of a certain particle size at a suitable position on the ground or underground, mixing the finished gangue powder with a certain proportion of water to form slurry, and then using a grouting pump to transport the slurry through the ground conveying pipeline and the underground conveying pipeline to the workable space adjacent to the goaf, and finally using the grouting borehole to fill the slurry into the residual space remaining after the overburden collapse; Low-position grouting utilizes the space of the original mining tunnel for filling, and grouting pipes are arranged in the drifts on both sides. During the continuous mining process of the working face, the grouting filling pipes are arranged in the two mining tunnels in advance to realize hanging pipe filling.