METHOD FOR RECOVERING ROOM-MINING COAL PILLARS BY SOLID FILLING IN SYNERGY WITH ARTIFICIAL PILLARS

Abstract

A method for recovering room-mining coal pillars by solid filling in synergy with artificial pillars. Solid materials and cementing materials on the ground are conveyed through a feeding well and a pipeline to a room-and-pillar goaf, a plurality of artificial pillars is cast at an interval in a coal room area, and gangue is cast to fill other regions of the coal room using a gangue casting machine. Under joint support by the artificial pillars and the coal room filler, coal pillars are recovered using a continuous coal mining machine, artificial pillars are cast in the original coal pillar area after recovery, and gangue is cast to fill the original coal pillar area using the gangue casting machine. A system for recovering room-mining coal pillars by solid filling in synergy with artificial pillars mainly includes a material conveying system, a joint support system, and a coal pillar recovery system. By constructing pillar grooves, casting artificial pillars, casting gangue to fill a goaf, and recovering coal pillars, the recovery rate of coal resources can be increased, and room-mining coal pillar recovery theories and technologies in China can be enriched while harmonious development of environmental protection and resource exploitation is promoted.

Claims

1. A method for recovering room-mining coal pillars by solid filling in synergy with artificial pillars, comprising the following steps: a. under a joint support to overlying strata by a filler in synergy with artificial pillars, recovering room-mining coal pillars using a continuous coal mining machine: firstly, conveying solid materials and cementing materials on a ground through a feeding well and a conveying pipeline to a room-and-pillar goaf; b. casting a plurality of artificial pillars at an interval in the room-and-pillar goaf between the room-mining coal pillars, filling areas between the cast artificial pillars, and by tamping and reinforcing, to form a coal room filler; c. under the joint support by the cast artificial pillars and the coal room filler, recovering the room-mining coal pillars one-by-one in a joint support area using the continuous coal mining machine till all the room-mining coal pillars are recovered.

2. The method for recovering room-mining coal pillars by solid filling in synergy with artificial pillars according to claim 1, wherein the recovery process of a single room-mining coal pillar comprises the following steps: a. firstly constructing square pillar grooves having sides of 4 m long at an interval in the room-and-pillar goaf on one side of the room-mining coal pillar, and building retaining walls in the constructed square pillar grooves, wherein the retaining walls are required to be tightly sealed and contact a roof completely and closely; b. constructing artificial pillars by injecting slurry into the constructed square pillar grooves, and when a height of the slurry for casting the artificial pillars reaches a position that is 50 mm below the roof, increasing a concentration of the slurry and performing roof-contacted filling on the artificial pillars; c. after casting of the artificial pillars, casting gangue to fill the room-and-pillar goaf using a gangue casting machine, and also, tamping and reinforcing using a bulldozer; d. repeating Steps a to c to complete filling of the room-and-pillar goaf on the other side of the room-mining coal pillar; e. after a strength of the artificial pillars and the coal room filler reaches initial rock stress, recovering the room-mining coal pillar using the continuous coal mining machine in a horizontal recovery manner, the recovery being carried out in a cross-shuttling order; f. casting artificial pillars in the area of the recovered room-mining coal pillar, and casting gangue to fill the area of the room-mining coal pillar using the gangue casting machine, thus achieving mining first and filling later on a working face.

3. The method for recovering room-mining coal pillars by solid filling in synergy with artificial pillars according to claim 2, wherein the artificial pillars are cast at an interval of 15 m to 17 m, most preferably 16 m.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 is a diagram illustrating the technical principle of a method for recovering room-mining coal pillars by solid filling in synergy with artificial pillars according to the present invention.

[0020] FIG. 2(a) is a top view of arrangement of artificial pillars in the method for recovering room-mining coal pillars by solid filling in synergy with artificial pillars according to the present invention.

[0021] FIG. 2(b) is a cross-sectional view of arrangement of artificial pillars in the method for recovering room-mining coal pillars by solid filling in synergy with artificial pillars according to the present invention.

[0022] FIG. 3(a) is a top view of reinforcement and filling state in the method for recovering room-mining coal pillars by solid filling in synergy with artificial pillars according to the present invention.

[0023] FIG. 3(b) is a cross-sectional view of reinforcement and filling state in the method for recovering room-mining coal pillars by solid filling in synergy with artificial pillars according to the present invention.

[0024] FIG. 4(a) is a top view of recovering and filling state in the method for recovering room-mining coal pillars by solid filling in synergy with artificial pillars according to the present invention.

[0025] FIG. 4(b) is a cross-sectional view of recovering and filling state in the method for recovering room-mining coal pillars by solid filling in synergy with artificial pillars according to the present invention.

[0026] In the figures: 1feeding well, 2conveying pipeline, 3solid material, 4cementing material, 5room-mining coal pillar, 6artificial pillar, 7coal room filler, 8gangue casting machine, 9room-and-pillar goaf, 10continuous coal mining machine, 11pillar groove, 12roof.

DETAILED DESCRIPTION OF THE INVENTION

[0027] Embodiments of the present invention are further described below with reference to the accompanying drawings.

[0028] A method for recovering room-mining coal pillars by solid filling in synergy with artificial pillars provided by the present invention includes the following steps:

[0029] a. Under a joint support to overlying strata by a filler in synergy with artificial pillars, adopting a method of recovering room-mining coal pillars 5 by a continuous coal mining machine: firstly, conveying solid materials 3 and cementing materials 4 on a ground through a feeding well 1 and a conveying pipeline 2 to a room-and-pillar goaf 9.

[0030] b. Casting a plurality of artificial pillars 6 at an interval in the room-and-pillar goaf 9 between the room-mining coal pillars 5, while casting gangue to fill the room-and-pillar goaf between the cast artificial pillars 6 using a gangue casting machine 8, and tamping and reinforcing using a bulldozer, to form a coal room filler 7, where the artificial pillars 6 are cast at an interval of 15 m to 17 m, most preferably 16 m.

[0031] c. Under the joint support by the cast artificial pillars 6 and the coal room filler 7, recovering the room-mining coal pillars 5 one-by-one in a joint support area using the continuous coal mining machine 10, casting artificial pillars 6 in the original coal pillar area after recovery, and casting gangue to fill the original coal pillar area using the gangue casting machine till all the room-mining coal pillars are recovered. A system for recovering room-mining coal pillars by solid filling in synergy with artificial pillars mainly includes a material conveying system, a joint support system, and a coal pillar recovery system.

[0032] The recovery process of a single room-mining coal pillar includes the following steps:

[0033] a. Firstly constructing square pillar grooves 11, having sides of 4 m long, for building retaining walls and carrying out artificial casting at an interval in the room-and-pillar goaf 9 on one side of the room-mining coal pillar 5, and building retaining walls in the constructed square pillar grooves 11, where the retaining walls are required to be tightly sealed and contact a roof 12 completely and closely.

[0034] b. Constructing artificial pillars 6 by injecting slurry into the constructed square pillar grooves 11, where during casting of the artificial pillars 6, the casting is carried out many times from bottom to top in order to avoid uneven strength in the vertical direction of the artificial pillars 6 that is caused by segregation of the slurry in the case of one-time filling; and when the height of the slurry for casting the artificial pillars 6 reaches a position that is 50 mm below the roof 12, increasing the concentration of the slurry and performing roof-contacted filling on the artificial pillars 6.

[0035] c. After casting of the artificial pillars 6, casting gangue to fill the room-and-pillar goaf 9 using the gangue casting machine 8, and also, tamping and reinforcing using the bulldozer.

[0036] d. Repeating Steps a to c to complete filling of the room-and-pillar goaf 9 on the other side of the room-mining coal pillar 5.

[0037] e. After a strength of the artificial pillars 6 and the coal room filler 7 reaches initial rock stress, recovering the room-mining coal pillar 5 using the continuous coal mining machine 10 in a horizontal recovery manner, the recovery being carried out in a cross-shuttling order.

[0038] f. Casting artificial pillars 6 in the area of the recovered room-mining coal pillar 5, and casting gangue to fill the area of the room-mining coal pillar 5 using the gangue casting machine 8, thus achieving mining first and filling later on a working face.