US20200024944A1

US20200024944A1 - Method of mining single steeply-inclined thick coal seam

Info

Publication number: US20200024944A1
Application number: US16/498,126
Authority: US
Inventors: Zhongping GUO; Wenwu XIE; Haiyan Fan; Huiqiang DUAN; Hengze YANG; Yong JIAN
Original assignee: Shandong University of Science and Technology
Current assignee: Shandong University of Science and Technology
Priority date: 2018-01-18
Filing date: 2018-05-11
Publication date: 2020-01-23
Also published as: CN108150172A; WO2019140812A1

Abstract

Provided is a method of mining a single steeply-inclined thick coal seam, which belongs to the mining engineering field. The mining method includes: carrying out one transport crossheading along a floor of the coal seam to constitute a production system together with rises on both sides of a district; arranging a top-coal caving hydraulic support along a thickness of the coal seam in the transport crossheading, with a cyclic advance interval being 1.0 m; maintaining one section of return air channel close to a side of a roof that is in a gob and behind the hydraulic support. In a case of mining, caved coals fall on a scraper conveyer and transported through a belt conveyer. Fresh air flow required for a working surface enters the transport crossheading through a district transport crosscut and a track rise, and then enters the return air rise through the return air channel after washing the working surface. A unique return air channel is adopted. The method features advantages such as simple roadway arrangement system, strong adaptability, large yield of working surface, and high safety level.

Description

TECHNICAL FIELD

The present disclosure relates to the field of coal mining technology and in particular to a method of mining a single steeply-inclined thick coal seam

BACKGROUND

A method of mining steeply-inclined thick coal seam always is a difficult problem in the mining technology field and already draws attention of relevant state authorities. Steeply-inclined thick coal seams in China are mostly distributed in small and medium-sized mines. Geological conditions of the coal seams are complex and the coal seams are difficult to mine. Some mines have features such as many faults, less reserves, high content of gas and bad storage conditions. Because the steeply-inclined coal seam is special, there are many problems with mining, for example, a loss ratio of coals is up to 40-50% and a gangue ratio of the coals is generally below standard; an drivage ratio of roadway is high, and the drivage ratio of roadway affects the expenses of roadway drivage and maintenance, affects handover of working surfaces of a mining zone and even bring an impact to ventilation of mining shafts; ventilation conditions are bad, ventilation conditions of the steeply-inclined coal seam are very complex; labor intensity of workers is high, mining personnel often encounters problems such as a large slope of working surface, small space, falling coals during mining, and difficulties in supporting, transporting materials and walking during a mining process due to limitation of complex mining conditions of the steeply inclined coal seam; mining benefit is bad, and compared with inclined or nearly horizontal coal seams, the steeply inclined coal seam has disadvantages such as high costs, bad quality, high mining difficulty level, small scale, and low benefits. Therefore, research on the method of mining a steeply inclined thick coal seam still has significant impact on the development of Chinese coal industry.

SUMMARY

The object of the present disclosure is to provide a method of top coal caving for mining a single steeply-inclined thick coal seam. A roadway is arranged simply, a drivage ratio of the roadway is reduced, and a mining working surface adopts mechanized production to facilitate operation and transportation. With a unique return air channel, ventilation is very convenient.
A technical problem to be solved by the present disclosure to complete the above task is that: how to complete advanced temporary supporting of a coal mining working surface, and keep the working surface normally ventilated to maintain a return air channel on a precondition of ensuring normal mining of the working surface.
To solve the above technical problem, the following technical solution is adopted in the present disclosure.
A system for mining a single steeply-inclined thick coal seam includes a roadway arrangement system, a supporting system, a transportation system and a ventilation system. The roadway arrangement system is formed by a transport crossheading and a district rise, the transport crossheading is arranged on a floor of the thick coal seam and the district rise is obtained by connecting two sides of the coal seam.
The supporting system includes a top-coal caving hydraulic support, a single hydraulic support, a hinged top beam, an anchor bolt and a metal net. The top-coal caving hydraulic support is located in the transport crossheading, a roof in the roadway is supported by disposing an anchor bolt with protection provided by a disposed metal net, and advanced temporary supporting is completed in cooperation with the single hydraulic support and the hinged top beam located in front of a working surface.
The transportation system includes a scraper conveyer and a belt conveyer. A head of the scraper conveyer is overlapped with a tail of the belt conveyer.
The ventilation system includes a return air channel. The return air channel is close to a coal seam roof side that is behind the top coal caving hydraulic support and in a gob. The return air channel is used to allow dirty air washing the working surface to enter a return air rise in the district rise.
For the above return air channel, one herringbone return air channel is maintained by I steel at a side of the gob behind the top coal caving hydraulic support.
As a preferred solution of the present disclosure, the transport crossheading adopts a quadrilateral roadway.
As another preferred solution of the present disclosure, a cyclic advance interval of the top-coal caving hydraulic support is 1.0 m.
Further, there is only one transport crossheading in the roadway arrangement system.
Another object of the present disclosure is to provide a method of a top-coal caving for mining a single steeply-inclined thick coal seam.
The method of mining a single steeply-inclined thick coal seam includes the following steps in sequence.
a. The transport crossheading is carried out along a floor of a coal seam to connect the district rises on both sides of the coal seam.
b. The top-coal caving hydraulic support is arranged along a coal seam thickness within the transport crossheading, and each cyclic advance interval of the top-coal caving hydraulic support is 1.0 m.
c. One section of return air channel is maintained at a side of the gob of the top-coal caving hydraulic support; a next section of return air channel is maintained with advance of the top-coal caving hydraulic support to lead to a district return air rise and so on.
d. The working surface is advanced by adopting full seam mining of top coal caving and the caved coals are transported out by the transportation system.
e. Fresh air flow arrives at a track rise through a district transport crosscut and then enters the transport crossheading and then to the mining working surface. The dirty air washing the working surface arrives at the district return air rise through the return air channel and then enters a mining shaft return air system.
The mining method is applicable to mining of a single steeply-inclined thick coal seam of more than 5.5 m.
The above technical solution has the following difficult points: to keep the mining working surface normally ventilated, it is required to maintain one section of return air channel before caving of the gob; and a proper advance interval of the top-coal caving hydraulic support is determined to ensure a high coal recovery ratio, a low gangue ratio and a high caving efficiency.
Preferably, at step d, the caved coals fall on the scraper conveyer and scattered coals are loaded onto the scraper conveyer and then coals are transported out in cooperation with the belt conveyer.
The beneficial technical effects of the present disclosure are described below.
The mining method of the present disclosure improves production capacity of the working surface and reduce the drivage ratio of the roadway and may be applied to mine a single thick coal seam of more than 5.5 m, where the transport crossheading and two rises constitute ventilation, thereby avoiding the problems of ventilation and gas accumulation at the time of top coal caving and improving the environment of the working surface.
The method of present disclosure is characterized as follows:
(1) According to the method of top coal caving for mining a single steeply inclined thick coal seam of the present disclosure, characteristics such as a large dip angle of coal seam and a small roof pressure are fully utilized to form a complete production system. In this way, the problems that coals and gangues mined from a steeply-inclined coal seam according to a conventional method roll along the floor to easily harm persons and knock down supports and so on are solved, thereby realizing high yield and high efficiency of mining the steeply-inclined coal seam.
(2) Another feature of the present disclosure is to maintain one return air channel by I steel within the gob, so that the transportation and ventilation of coals can be completed with only one transport crossheading. Along with advance of the top-coal caving support, the return air channel is maintained behind the working surface so that fresh air flow enters the working surface, and the dirty air washing the working surface enters the return air rise through maintained return air channel, thereby forming a complete ventilation system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a working surface of a mining method according to an example of the present disclosure.

FIG. 2 is a top view of a working surface arrangement according to an example of the present disclosure.

FIG. 3 is a top view of a district rise arrangement manner according to an example of the present disclosure.

In the drawings, 1 refers to a coal seam, 2 refers to a transport crossheading, 3 refers to a top-coal caving hydraulic support, 4 refers to a return air channel, 5 refers to I steel, 6 refers to a scraper conveyer, 7 refers to a belt conveyer, 8 refers to a gob, 9 refers to a return air rise, 10 refers to a track rise, 11 refers to a transport rise.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present disclosure provides a method of mining a single steeply-inclined thick coal seam. To describe the advantages and technical solutions of the present disclosure more clearly, the present disclosure will be detailed below in combination with specific examples.
As shown in FIGS. 1, 2, and 3, there is provided a system for mining a single steeply-inclined thick coal seam, including a roadway arrangement system, a supporting system, a transportation and a ventilation system. The roadway arrangement system is formed by a transport crossheading 2, a return air rise 9, a track rise 10, and a transport rise 11. The transport crossheading 2 is arranged at the roof of the thick coal seam, and the return air rise 9, the track rise 10 and the transport rise 11 are obtained by connecting both sides of the coal seam. The supporting system includes a top-coal caving hydraulic support, a single hydraulic support and a hinged top beam. The top coal caving hydraulic support is arranged at the position of the top coal caving hydraulic support shown in FIG. 2 and is located within the transport crossheading and further arranged along the thickness of the coal seam. The transportation system includes a scraper conveyer 6 and a belt conveyer 7. A head of the scraper conveyer 6 is overlapped with a tail of the belt conveyer 7. The ventilation system includes a return air channel 4 and a I steel 5. The return air channel is maintained by the I steel at the side of the gob behind the top-coal caving hydraulic support and used to allow the dirty air washing the working surface to enter the return air rise in the district rise.

Example 1

Descriptions are made with a mine A mining shaft 2 coal seam as an example.
The basic conditions are as follows: 2 coal seam is mined in the mining shaft, the coal seam is 5.8 m thick, an dip angle of the coal seam is 55 degrees, and the lithology of the roof and the floor is relatively stable siltstone and fine sand stone.
The coals are mined by the above mining method.
The transport crossheading is carried out by adopting a quadrilateral roadway along a floor of the coal seam 1. The top-coal caving hydraulic support 3 is arranged in the coal seam 1, the scraper conveyer 6 is placed along a strike between supports in the transport crossheading of the coal seam 1 and the belt conveyer 7 is installed at a proper position in the transport crossheading. The head of the scraper conveyer 6 is overlapped with the tail of the belt conveyer 7 to form a raw coal transportation of the working surface. Each cyclic advance interval of the supports of the working surface is 1.0 m. The working surface is advanced by natural caving of coal seam and then low-position caving of the top coal. The advance supporting of the working surface is performed by supporting with an anchor bolt and a metal net in cooperation with supporting of the single hydraulic support and the hinged top beam. When one cyclic advance interval is reached, fixing is performed with fixed piles so that the support forward-pushing cylinder is connected with the fixed pile to advance the supports alternately one by one, and then a next section of return air channel is maintained into the gob 8 behind the support by I steel 5 at the side of the transport crossheading. In a case of top coal caving, the coals falling from a caving opening slide to the scraper conveyer through a special chute and the scattered coals are shoveled to the scraper conveyer by hand for transportation.
As shown in FIGS. 1, 2 and 3, the ventilation path is described as follows: fresh air flow enters the transport crossheading of the coal seam 1 through the track rise 10 and gets to the mining working surface and then the dirty air arrives at the district return air rise 9 through the previously maintained return air channel 4 and then enters the mining shaft return air system through the district return air crosscut.
The present disclosure has the following advantages:
Firstly, the drivage ratio of the roadway is low, and there is only one transport crossheading. In this case, maintenance expenses of the roadway drivage are reduced.
Secondly, the yield of the working surface is large and the coal loss is small.
Thirdly, the working surface is arranged simply with high adaptability and is applicable to mining of a steeply-inclined thick coal seam of more than 5.5 m.
Fourthly, for mining of top coal caving, a professional top coal caving hydraulic support is used in cooperation with low position top coal caving. The operation is simple and fewer workers are needed. For example, 4-5 persons are needed for each shift.
Fifthly, a unique return air channel is adopted to solve the problems of bad ventilation conditions and gas accumulations on the working surface, thereby improving safety of the working surface and the working environment of the workers.
Parts not mentioned in the present disclosure may be implemented by using the prior art.
Although many terms such as the belt conveyer and the hydraulic supports are used in the present disclosure, the possibility of using other terms is not precluded. Those simple substitutions made by those skilled in the art for these terms according to the teachings of the present disclosure shall all fall within the scope of protection of the present disclosure.

Claims

1. A system for mining a single steeply inclined thick coal seam, comprising a roadway arrangement system, a supporting system, a transportation system and a ventilation system, wherein,

the roadway arrangement system is formed by a transport crossheading and a district rise, the transport crossheading is arranged at a floor of the thick coal seam and the district rise is obtained by connecting both sides of the coal seam;

the supporting system comprises a top-coal caving hydraulic support, a single hydraulic support, a hinged top beam, an anchor bolt and a metal net, the top-coal caving hydraulic support is located in the transport crossheading, a roof in the roadway is supported by disposing an anchor bolt with protection provided by a disposed metal net, and advanced temporary supporting is completed in cooperation with the single hydraulic support and the hinged top beam located in front of a working surface;

the transportation system comprises a scraper conveyer and a belt conveyer, and a head of the scraper conveyer is overlapped with a tail of the belt conveyer; and

the ventilation system comprises a return air channel, the return air channel is close to a coal seam roof side that is behind the top coal caving hydraulic support and in a gob, the return air channel is used to allow dirty air washing the working surface to enter a return air rise in the district rise.

2. The system for mining a single steeply-inclined thick coal seam according to claim 1, wherein the transport crossheading adopts a quadrilateral roadway.

3. The system for mining a single steeply-inclined thick coal seam according to claim 1, wherein a cyclic advance interval of the top coal caving hydraulic support is 1.0 m.

4. The system for mining a single steeply-inclined thick coal seam according to claim 1, wherein there is only one transport crossheading in the roadway arrangement system.

5. A method of mining a single steeply-inclined thick coal seam, comprising in sequence:

a. carrying out a transport crossheading along a floor of the coal seam to connect district rises on both sides of the coal seam;

b. arranging a top coal caving hydraulic support in the transport crossheading along a thickness of the coal seam, each cyclic advance interval of the top coal caving hydraulic support being 1.0 m;

c. maintaining one section of return air channel at a side of a gob of the top coal caving hydraulic support, and maintaining a next section of return air channel along with advance of the top coal caving hydraulic support to lead to a district return air rise and so on;

d. advancing the working surface by full seam mining of top coal caving and transporting out the caved coals by a transportation system;

e. fresh air flow arriving at a track rise through a district transport crosscut and then entering the transport crossheading and then to the mining working surface, and dirty air washing the working surface arriving at the district return air rise through the return air channel and then entering a mining shaft return air system;

wherein the mining method is applicable to mining of a single steeply-inclined thick coal seam of more than 5.5 m.

6. The method of mining a single steeply-inclined thick coal seam according to claim 5, wherein, at step d, the caved coals fall on the scraper conveyer and scattered coals are loaded onto the scraper conveyer and then the coals are transported out in cooperation with the belt conveyer.