AU2314801A

AU2314801A - A method for increasing producing capacity of a full-mechanized top-coal caving face

Info

Publication number: AU2314801A
Application number: AU23148/01A
Authority: AU
Original assignee: Yankuang Group Corp Ltd
Current assignee: Yankuang Group Corp Ltd
Priority date: 2000-02-20
Filing date: 2001-02-20
Publication date: 2001-08-23
Also published as: CN1310285A; CN1129703C

Description

Our Ref:7563280 P/00/011 Regulation 3:2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT a.

Applicant(s): Yankuang Group Corporation No. 40 Fushan Road Zoucheng City Shandong 273500 People's Republic of China DAVIES COLLISON CAVE Patent Trade Mark Attorneys Level 10, 10 Barrack Street SYDNEY NSW 2000 Address for Service: Invention Title: A method for increasing producing capacity of a fullmechanized top-coal caving face The following statement is a full description of this invention, including the best method of performing it known to me:- 5020 A method for increasing producing capacity of a full-mechanized top-coal caving face The invention relates to a coal mining method.

Up to now, the most effective method in thick seam coal mining is the full-mechanized top-coal caving, which is called the mechanized caving for short. This method is described in detail in the book "The Practice and Knowledge of Full-Mechanized Top-Coal Caving in Yanzou Coal Mine" (Zezhi WU, Coal Industry Press, November 1997). As mentioned in Chapter 5 of the book, a complete technological process of a full-mechanized top-coal caving mainly comprises following steps, which are cutting coal, moving supports, moving front conveyor, caving top coal and moving rear conveyors etc. There are two kinds of the technological process: One cutting One caving as well as Two cutting One caving. One cutting One caving is caving once a time after one cutting; while Two cutting One caving is caving once a time after two cuttings. Moreover, a concurrent operation of cutting and caving is also used in order to increase the productivity of top-coal caving. That is, a long-wall face is divided into two parts so that the cutting can be carried out on a part of the long-wall face and caving on another part thereof simultaneously. In practice the productivity of a concurrent operation is larger than that of a single operation. However, the concurrent operation cannot be used in the technological process of One cutting One caving because of limitations of the technological parameters and top-coal caving equipments.

As the cutting depth of a current shearer is about 0.8 m, the caving interval is also about 0.8 m according to the technological process of One cutting One caving. In this case, the caving interval is so smaller that refuses will easily enter the caving window. If workers find refuses at the caving window, he will mistakenly believe that top coal has been fully caved out and then stop caving. This result not only coal losing but also low recovery. Since the rate of advance in every circulation is only 0.8 m, the productivity will also decrease. However, the method of One cutting One caving is simple in technological process, high in efficiency and easy in the roof control. When using the method of Two cutting One caving, the caving interval is up to 1.6 m that is double of the cutting depth. In this circumstance, the caving interval is so longer that it is difficult to control the roof and a part of top coal will fall into the gob area, which result in that :i some coal is lost and the recovery is lowed. Only when a reasonable caving interval is selected, can the refuses above the coal seam and in the gob area simultaneously reach to the caving window so that the lost top coal will be reduced, the recovery will be raised and the roof can be easily controlled. According to the applicant's practice, the *oo.

reasonable caving interval should be about 1.0 1.4 m between One cutting One S caving and Two cutting One caving. Since the caving interval should be integral times of the cutting depth, an optimum-caving interval cannot be reached under the limitation ?o0 of the present depth of cut of the shearer. In addition, the process of Two cutting One caving is more complicate and the roof cannot be easily controlled.

Top-coal caving is an important process for a full mechanized top-coal caving, because most coal (about 50% to 70 at- a long-wall is caved at the rear of the supports.

Therefore, how to operate the supports is the crux for full-mechanized top-coal caving.

At present, supports for top-coal caving are hydraulic supports. Several operating valves are provided in the hydraulic supports. The operating valves are operated manually using handles to control the hydraulic supports. Conventionally, when a predetermined caving interval is reached, first the gate of rear beam is opened to cave crushed coal above the gate. If the coal flow is too small, the rear beam is oscillated to continue the caving. At last the gate is opened further to cave block coal. Until the refuses are about 1/3 in coal, the rear beam is raised and the gate is closed to stop caving. Owing to different occurrence of coal seams, there is various coal caving methods. The most important for a caving method is the caving sequence one by one support or every other support) and caving times for each support (single caving, double caving or multi-caving). Therefore, various caving methods are used, such as single caving, two-times caving, single caving for every other supports, single caving for one and the last supports, etc. Since workers embody the above complicate technological methods manually, the duration of top-coal caving is so longer as to affect the production, and more workers are needed because of the low automation. At the same time, the intensity of labor is higher and the safety is lower.

*o• Presently, electro-hydraulic controlled hydraulic supports are provided in full-mechanized coal mining at abroad to reach the automatic control. However, there are no full-mechanized caving faces at abroad so that no full-mechanized caving supports exist accordingly. There are also no full-mechanized supports used at full-mechanized caving faces and program-controlled electronic-hydraulic valves in China.

The object of the present invention is to overcome the shortcomings of the process and the parameters of the full-mechanized top-coal caving, providing a caving method that has reasonable parameters and can raise the automatic degree, increasing the coal production and recovery, reducing the number of operators at a long-wall face and the intensity of labor and increasing the overall benefit as well as the safety.

The method of the present invention comprises cutting and transporting coal, moving supports and the front conveyor, moving the rear conveyor and caving coal. The method of the present invention is characterized in that it comprising following steps: 1) M• carrying out One cutting One caving with the cutting depth 1.0 1.4 m; 2) controlling the movements of supports by an electro-hydraulic program-controlled system to realize automatic supports' movement, especially to realize the automatic caving process. The details of the method are: 1) The drum shearer with a cutting depth of 1.0 1.4 m is used so that every cut is 1.0 1.4m.

2) The mining method of One cutting One caving is carried out with every caving interval of 1.0 1.4m.

3) The caving operation starts after the rear drum of the shearer within a range of 5 supports so that the cutting and caving are carried out simultaneity. This is called "parallel operation process "in this application.

4) An electro-hydraulic program-controlled system is provided in top-coal caving supports so as to sequentially control the supports according to a predetermined process and to carry out the automatic supports advancing, top coal caving as well as pushing of the conveyors. The electro-hydraulic program-controlled system comprises a main controller and a plurality of electrical-hydraulic controlled valves. Working programs are input into the main controller so that the valves can control the movements of the supports automatically, especially can control the caving automatically.

Top coal caving is carried out with group caving and single caving for each other support or multiple caving.

6) In order to control and monitor all actions of the top-coal supports, pressure sensors are fixed on the legs of the supports and displacement sensors are fixed on the s5 cylinder of rear beam and on the advancing rams. Approach switches are fixed on the cylinder of the caving gate. All signal lines are connected correspondingly to the interfaces of the main controller. The above sensors can also be provided in the corresponding hydraulic pipes.

7) All the main controllers of the supports are connected in series so as to allow o operations on any one of the supports at the long-wall face to control the whole supports.

The advantages of the invention are as follows. The process and the parameters for an One cutting One caving full-mechanized top-coal caving method according to the present invention are optimized so that the coal production and recovery are increased simultaneously, since the cutting parameters and the corresponding shearers are selected on the basis of the reasonable caving intervals. Furthermore, the caving supports controlled by the electro-hydraulic program-controlled system provide a reasonable caving method, which is difficult to be carried out manually by workers, so that the complicate manual operations are replaced by the automatic control process, numbers of the workers are reduced, the coal production and recovery as well as the average efficiency of workers are increased. Because of the above reasons, the total benefit of the full-mechanized top-coal caving in the long-wall face is increased while the labor intensity of workers is reduced and the production safety is improved.

Preferred embodiments according to the invention will be explained in more detail with reference to the drawings, in which: 00 Fig. 1 is a schematic side view of a support, in which the hydraulic pipes of legs and S cylinders are omitted; Fig.2 is a principle block diagram of the electro-hydraulic program-controlled system provided with the PM 3 controller; Fig. 3 is the main process diagram for a two-times caving.

Reference numerals in the Figures indicate: 1 support body; 2 electro-hydraulic valve assembly; 3 main controller; 4 pressure sensors of the front and rear legs; 5 displacement sensors for pushing the conveyor and advancing the support; 6 the displacement sensor for moving the rear beam; 7 an approach switch of the caving gate.

A. Before mining, a set of full-mechanized equipments should be provided at a long-wall face, which include a shearer, conveyors, top-coal caving supports and face end supports, etc, in which: 1. The main parameters of the shearer should meet that its cutting depth is m and shear height is 1.8 3. 5 m; 2. The main parameters of the conveyors should meet that the width of the front conveyor is 1.0 m, the transport capacity is more than 1500 ton/h, the width of the rear conveyor is 1.2 m and the transport capacity thereof is more than 2000 ton/h; 3. The main parameters of the top-coal caving supports should meet that the working resistance is 6800 KN, the mean load density is 0.8 MPa;

S

4. An electro-hydraulic program system is provided in the caving supports. As shown in Figure 1, the structure of the support body according to the invention is identical with that in the prior art so that it is unnecessary to describe it in detail. It is important that the electro-hydraulic program-controlled system composed of electro-hydraulic controlled valve assembly and main controller is disposed on the support body The controller of the system is the Controller PM 3 produced by Marco Company in Germany. The pressure sensors are disposed on the cylinders of the legs. The displacement sensors are fixed on the advancing rams.

The displacement sensors are disposed on the rear beam cylinders. The approach switch is fixed on the caving gate. The interfaces of the main controller PM 3 are connected respectively with the sensors, switches and electro-hydraulic controlled valves by cables.

As shown in Figure 2, interfaces Al and Fl are connected respectively with corresponding interfaces Al and Fl of the two adjacent supports. A2 is connected with earth protective device DB, and B1 with the approach switch fixed on the caving gate, C1 and C2 with the pressure sensors of the front and rear legs, D1 with the displacement sensor for pushing the conveyor and advancing the support El with 0*@*4e 4 the displacement sensor on the rear beam, F2 with the solenoid valve DC of the electro-hydraulic controlled valve. Eight pairs of inlets and outlets provided on main valve DY of the electro-hydraulic controlled valve are respectively connected with the corresponding pressure pipes of the supports so as to control liquid entering and returning from each pressure pipe of the supports and to raise the front and rear legs of the support, advance the support forward and push the front conveyor, raise or reduce the rear beam, open and close the caving gate, stretch out and retract the face sprag, advance the rear conveyor and stretch out and retract the side shield of the support, etc.

B. Mining process 1) Cutting coal by shearer.

After being actuated the shearer cuts slantingly into coal with the cutting depth m at any position of the long face. At the same time, the front conveyor is actuated to transport cut coal out of the long face and the face sprag of the third support before the front drum of the shearer is retracted.

2) Advancing supports.

In general one of the 3 d to 5 t h supports after the rear drum of the shearer is advanced forward with 1.0 m of a unit advance. The supports are advanced in sequence one after *o S• another by pressing the starting button of the main controller to follow the shearer's movements. The operational sequence for moving the supports is as follows: lowering supports advancing supports raising supports( to stop raising up to about pump pressure) stretching out the face sprag.

3) Moving the front conveyor.

In general the part of the front conveyor after the 5 h to .10 h supports of the moved support is pushed in 3 to 4 times into position by the advancing ram of the support so as to follow the shearer's advancing, wherein the unit advance is 1.0 m.

4) Advancing the rear conveyer.

The operation is as same as that of the front conveyer.

Caving coal.

Caving operation is carried out at one of 5 t h to 10 t h support after the rear drum of the l0 shearer to follow the shearer's advancing. That is, cutting and caving are carried out simultaneously. The top-coal caving supports cave coal automatically according to a S predetermined caving program. The basic caving process for each support at each time is as follows: drawing back the caving gate to open the caving windows) lowering the rear beam raising the rear beam stretching out the caving gate to close the caving window A plurality of top-coal caving methods can be formed by combining S the number of the supports in which the caving gates are opened simultaneously, the interval for opening the caving gate of each support and the times for opening the caving *o gate of each support.

S.

o• The caving method comprises group caving and single caving for each other support or multiple caving. According to said group caving, 2 to 4 supports form a group and all caving gates in this group are opened simultaneously. According to single caving for each other support or multiple caving, each caving gate is opened orderly or a certain caving gate/gates in a certain group is/are opened several times during the predetermined interval.

The above process is automatically controlled by PM3 controller. After pressing the starting button, all the actions of the supports are completed automatically.

C. In order to embody the invention conveniently, requirements of the program for automatically controlling the top-coal caving supports are as follows.

1) According to the structure of the top-coal caving supports and the mining process, 17 basic actions controlled by electro-hydraulic program-controlled system comprise: (1) Sraising the front legs; lowering the front legs; raising the rear legs; lowering the rear legs; advancing the supports; pushing the front conveyer; stretching S: the face sprag; drawing back the face sprag; advancing the rear conveyer; 1l opening the caving gate (to cave coal); (11) closing the caving gate to stop caving); (12) raising the rear beam; (13) lowering the rear beam; (14) raising the base of the support (controlled by the same solenoid valve for advancing the support); (15) lowering the base of the support (controlled by the same solenoid valve for advancing the front *conveyer); (16) stretching the side shield; (17) retracting the side shield. The total is basic controlling functions (two of them are merged) and 1 spare controlling function.

Therefore, a control valve assembly with 16 functions can be selected.

2) The requirements for automatically controlling the electro-hydraulic controlled system are as follows.

Controlling the adjacent supports (on the left side or right side) and a group of the supports. On any one of the supports the adjacent supports can be operated or a number of the supports are automatically organized into groups in which the working cycle of all supports is automatically carried out one by one according to the predetermined time (or the pressure signal).

Advancing the conveyers group by group. On any one of the supports, the conveyers can be advanced sequentially from head to end of the conveyer or vice versa to advance the supports group by group or one after another so that the shearer can slantwise cut into coal wall.

Caving coal. A controlling parameter for the caving process is caving time, S. which can be adjusted on the main controller at site to adapt to various conditions of geology and to realize the balance caving in groups and single caving for each other support or multiple caving.

When caving, the caving gate and rear beam have the interlocking function.

That is, only when the caving gate is withdrawn at first and after the caving gate has see* been drawn back, can the rear beam be lowered. The rear beam is oscillated according to the predetermined oscillatory times. Only when the rear beam has been raised, can the caving gate be stretched. An approaching switch ensures the reliability of the interlocking function. If the approaching switch is disfunctional, the system can automatically lock this support. If the caving gate cannot be moved because of the pressure of coal or cannot be stretched because of block coal, the rear beam can automatically be oscillated up and down to ensure the caving gate stretching or withdrawing.

If necessary, the operation can be directly done manually in order to control a certain action of the support in action or its adjacent supports or to make the whole system pause.

Emergency function. The other supports in the whole face can still work normally even if one of the supports fails. If the hydraulic pipe leaks, the system will automatically stop working and sound an alarm.

D. The basic program for two-times caving in the multi-times sequence caving is illustrated below with reference to Figure 3.

se i! When caving, top coal behind the support is caved at two times within a 0o0..' predetermined time. Every caving is called one turn and the caving gate is continuously opened two times in every turn. In the first turn the caving gate is opened one time and oooo the rear beam is also oscillated one time. In the second turn the caving gate is opened once time but the rear beam is oscillated twice. The operation time is as follows.

1. In each turn the caving time is from the opening of the caving gate (caving gate is withdrawn) to the last closing of the caving gate (the caving gate is stretched out completely). The adjusting range is from 15 to 90 seconds. Basically, the first turn is 30 seconds and the second turn is 36 seconds.

2. The opening time td )for actuating the caving gate from the completely closed position to the completely opened position is 3.5 seconds.

3. The closing time te )for actuating the caving gate from the completely opened position to the completely closed position is 3.5 seconds.

4. The time to for maintaining the caving gate in the completely opened position is 8 seconds in the first turn and is 11 seconds in the second turn.

When the caving gate is completely opened to cave top coal, the rear beam is oscillated up and down. In the first turn the time ti during which the rear beam is oscillated up is 4 seconds in the first turn and the time th during which the rear beam is oscillated down is 4 seconds. In the second turn, the rear beam is respectively oscillated up and down 3 seconds and then is respectively oscillated up and down 2 2.5 seconds.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general acknowledge in Australia.

Claims

1. A method for increasing producing capacity of a full-mechanized top-coal caving face, comprising cutting coal, advancing supports, pushing the front conveyer, caving coal and moving the rear conveyor, carrying out One cutting One caving, wherein: 1.1 a drum shearer with a cutting depth of 1.0 1.4 m is used so that every cut is 1.0 1.4 m; the caving operation starts after the rear drum of the shearer within a range of 5 10 supports with caving interval of 1.0 1.4 m so that the cutting and caving are carried out simultaneity; 1.2 an electro-hydraulic program-controlled system is provided in top-coal caving supports so that an automatic controlled caving operation is carried out according to a predetermined caving process.

2. The method according to claim 1, wherein said caving process comprises group caving and single caving for each other support or multiple caving.

3. A method for increasing production capacity of a top-coal caving face substantially as hereinbefore described with reference to the drawings. DATED this 20 t day of February, 2001 YANKUANG GROUP CORPORATION By Its Patent Attorneys DAVIES COLLISON CAVE