US20120098325A1

US20120098325A1 - Method for the Automated Production of a Defined Face Opening by Means of Slope-Assisted Radar Navigation of the Roller of a Roller Cutter Loader

Info

Publication number: US20120098325A1
Application number: US13/380,692
Authority: US
Inventors: Martin Junker; Armin Mozar
Original assignee: Individual
Current assignee: RAG AG
Priority date: 2009-06-24
Filing date: 2010-06-18
Publication date: 2012-04-26
Also published as: CN102482941A; AU2010265133B2; DE102009030130B3; AU2010265133A1; RU2011152484A; DE102009030130B9; WO2010149315A2; CN102482941B; WO2010149315A3; RU2495243C2

Abstract

A method for automated production of a defined face opening in longwall mining operations in underground coal mining, comprising a face conveyor, disk shearer as extraction machine, and hydraulic shield support frame. At least one radar sensor is provided on a main body of the disk shearer. A distance between an upper edge of the main body and an underside of a top canopy of the shield support frame below which the main body travels during extraction work is measured, and is input into a computer as an actual value for a passage height of the disk shearer below the shield support frame. This actual value is compared with a target value and, if a deviation is determined, control commands are generated for adapting a cutting height of at least one of two cutting disks of the disk shearer.

Description

The present invention relates to a method for the automated production of a defined face opening for longwall mining operations comprising a face conveyor, a roller cutter loader or disk shearer as an extraction machine, and a hydraulic shield support in underground coal mining.
With the control of longwall mining operations during the extraction work, at stake is generally the best possible utilization of the available machine capacities while avoiding shutdowns, whereby if possible the necessary control processes should be automated in order to prevent incorrect human decisions. Beginnings of an automation of the control can be found in development or already in use, such as recognition/control of interfaces via sensors, learning step processes, recognition and control of the return path of the advancement support, automated advancement of the advancement support and automatic maintenance of a prescribed target inclination of the face conveyor.
One problem with the automation of longwall mining controls includes, among others, being able to ensure that in the forward region of the top canopy of each individual shield support frame, there is an adequate vertical height, in other words, an adequate face opening, in order to ensure that the disk shearer can travel by in a manner free of interference, since each collision of the disk shearer with the top canopy of a shield support frame because of a face opening that is too small leads to corresponding disruptions in operation or even damage to the equipment.
It is therefore an object of the present invention to provide a method of the aforementioned general type that provides indications of a possible collision between the disk shearer and the shield support frame or aids in preventing corresponding collisions.
The realization of this object, including advantageous embodiments and further developments of the invention, results from the content of the patent claims that follow this description.
The invention provides a method wherein the distance between the top or upper edge of the roller or disk base or main body and the bottom side or underside of the slope end cap or top canopy of the shield support below which the main body respectively travels during extraction work, i.e. below which the extraction work takes place, is measured by means of at least one radar sensor mounted on the roller or disk base body of the roller cutter loader or disk shearer, wherein the measured distance is entered into a computer as the actual value of the passage height of the roller cutter loader or disk shearer under the shield support and is then compared to a target value stored in the computer, wherein control commands for adapting the cutting height of at least one of the two cutter rollers or disks of the roller cutting loader or disk shearer are generated if a deviation is determined.
The invention has the advantage that the control objective of maintaining a defined face opening during the extraction travels of the disk shearer can be achieved with a relatively low expenditure. The passage height, which is measured as the distance between the upper edge of the main body of the disk shearer and the underside of the top canopy of the shield support, is also a direct measure for the face opening, since the face opening is composed of the passage height and the distances to the roof or overlying stratum assumed by the longwall equipment, and hence unalterable, on the one hand, and to the footwall or the footwall layer cut free by the footwall disk on the other hand. Thus, the distance to the overlying stratum that goes beyond the passage height is prescribed by the dimensions of the top canopy, while the distance of the radar sensors to the footwall layer is prescribed by the overall height of the face conveyor that rests upon the footwall layer and the main body of the disk shearer that can travel thereon. Thus, the value respectively measured for the passage height is used directly as a synonym for the height of the face opening. The control operations can thus be carried out more rapidly. The target value for the face opening prescribed in the computer is either prescribed by the deposit data, in other words in particular by the thickness of the seam, or is determined by the minimum passage height of the longwall equipment. As a function of the construction data of the longwall equipment, the target value can also be represented as the target travel for the passage opening.
If during the extraction value of the disk shearer it is established that the target value for the passage opening, which for example also contains a safety margin, is not reached or even exceeded, it is possible from the establishment of the deviation to generate control commands that alter or adapt the overall cutting height of the two cutting disks in such a way that the prescribed face opening that is to be maintained is again achieved. A particular advantage relative to the known methods is the short dead control time of only two successive extraction travels, since the face conveyor is then advanced onto the footwall layer that is cut free, and hence with the next passage of the disk shearer, the control result measured at the passage height that is then to be determined can be controlled. This still present dead control time inherently results from the required distance between the cutting disk, the face conveyor, and the radar sensors that are disposed on the main body of the disk shearer that travels on the face conveyor.
Pursuant to one specific embodiment of the invention, the alteration of the cutting height at the conclusion of an extraction travel of the disk shearer is undertaken along the face, so that the conditions during an extraction travel respectively remain constant and are respectively available for comparison purposes.
Alternatively, the alteration of the cutting height of the cutting disks can also be continuously effected as a reaction to the target value deviations detected in the computer; this results in an adaption to position changes of the longwall equipment at any given time.
Pursuant to one exemplary embodiment of the invention, a respective radar sensor is disposed at the additional ends of the main body of the disk shearer, whereby that radar sensor that is respectively toward the front as viewed in the direction of travel delivers the actual signals for the measured distance. Alternatively, the signals received by the two radar sensors can be continuously conveyed to the computer, where they are evaluated, whereby in the event that a deviation of the passage height measured by that radar sensor that is toward the front in the direction of travel from the target value is determined, a control command is immediately generated for the rear cutting disk of the disk shearer as viewed in the direction of travel.
If pursuant to one embodiment of the invention additionally the correction value of the cutting height of the cutting disks established during successive extraction travels by the respectively generated control commands are compared with one another for adjustment purposes, and the total value determined from the correction values is used as a measure for an input convergence and is taken into account with future extraction travels when a necessary cutting height adaptation is determined, it is possible in this manner to draw conclusions regarding a convergence that commences in the meantime. If during a first extraction travel there is a need for correcting the cutting height, it is possible to check for the next extraction travel whether after carrying out the correction the prescribed face opening is cut free. If in so doing a new requirement for correction results, this can be brought about only by a convergence that commences in the meantime.
Pursuant to one embodiment of the invention, the face height determination via the radar measurement is supplemented in that by means of the inclination sensors mounted on at least three of the four main components of each shield support frame, such as floor skid, gob shield, supporting connection rods, and that region on the top canopy of the side of the gob shield, the inclination of the shield support components relative to the horizontal are determined in the direction of advancement, and from the measured data, in a computer, by comparison with base data that is stored therein and that defines the geometrical orientation of the components and their movement during the advancement, the respective perpendicular height of the shield support frame at the front end of the top canopy is calculated as a measure for the actual face opening, and the thus determined actual values of the shield height calculation are conveyed to the computer, which processes the actual values from the passage height measurement. Whereas the radar measurement respectively delivers data only during the passage of the extraction machine below the respective shield support frame, and thus does not recognize a passage height that is too low from the outset and can be taken into account upon the determination of the extraction parameters, the supplemental determination of the face opening by means of the determination of the shield support height has the advantage that the data thus obtained at individual shield support frames provides additional information regarding the condition of individual sections of the face front, or the entire face front as extraction progresses, thus enabling an integral process control of the respective mining operation.
Thus, from the relationship of the calculated and the measured face opening relative to the deposit data applicable for the respective mining operation, such as the seam thickness that possibly changes over the length of the face, right from the start one can deduce whether there exists a danger of hang-ups within the longwall equipment due to the overlying stratum applying load to the shield support frames, or whether there is the threat that the upper adjustment limit of the shield support frame will be exceeded with an aspired-to automatic operation. The danger of getting hung-up exists when, with the commencement of convergence, the shield props are entirely retracted, and due to the fact that the overlying stratum then applies load, the shield frame is blocked and can no longer be moved away; a further possibility is that the steel construction can become blocked at the lower adjustment limit in the lemniscate gear mechanism of the shield support frame, or in the joint top canopy/gob shield, and also then can no longer be moved away. Finally, contact or striking of the top canopy of the shield support frame upon or on the upper edge of the brake of the face conveyor can occur, as a result of which a moving along of the face conveyor and/or an advancement of the shield support frame is similarly prevented or at least hindered to a great extent. The aforesaid moments of danger are particularly applicable when traveling through saddles or troughs in the contour of the seam or bed, which can be taken into account right from the beginning by means of an appropriate setting of the cutting height of the disk shearer. Furthermore, the corresponding face opening data can provide information about a possible caving from the roof or overlying stratum, the occurrence of narrowings of the seam, the “traveling-on-coal” by the disk shearer and/or a possible cutting of the disk shearer into the footwall.
Thus, the determination of the shield height delivers data for the face opening that is to be anticipated, which can then be compared with the data measured from the disk shearer as it passes through. Thus, the precisions of both manners of proceeding can be better estimated. To this extent, the two manners of proceeding complement one another, thus providing a redundancy when checking the respective face opening. A further advantage is that even if one of the two systems for determining the face opening fails, the extraction can continue on the basis of the remaining measurement system.
In this regard, pursuant to another embodiment of the invention, the actual values from the passage height measurement, taking into account the overall height of the top canopy and the construction of the face conveyor and the main body of the disk shearer, are converted into an actual face opening and are compared with the actual face opening as the product of the shield height calculation.
Further to be considered is that the inclination of the cutting disks of the disk shearer relative to the coal face in the direction of mining can have a considerable part in the alteration of the face opening by the cutting work. This inclination results from the fact that with a correction of the cutting height in particular of the footwall disk, traveling over the step that thereby results in the footwall layer leads to a tilting of the face conveyor relative to the footwall or even relative to the overlying stratum upon advancement of the face conveyor in the direction of mining due to the cutting width of the cutting disks, which is less than the width of the face conveyor with the main body of the disk shearer traveling thereon. Thus, with normal geometrical dimensions in the context of longwall equipment utilized these days, at a differential angle between the contour of the seam and the position of the face conveyor in the direction of mining of only 6 gon, there results a face height alteration of up to 100 mm, which can be corrected only in the course of further extraction travels. For this purpose, pursuant to a further development of the invention, the inclination of the face conveyor and/or disk shearer relative to the horizontal in the direction of mining is determined by means of inclination sensors mounted on the face conveyor and/or disk shearer, whereby the angle of inclination of the face conveyor and/or the disk shearer in a relationship to the angle of inclination determined at the top canopy of the shield support frame and/or at the floor skid thereof can be set, and the differential angle formed thereby can be taken into account in the calculation of the actual face opening that is to be established with successively following advancement cycles of the shield support frame. This has the advantage that the character of the face front can on the whole be recognized early, so that by timely counteracting, disadvantageous influences upon the face opening obtained by the mining work can be countered, to the extent that pursuant to one embodiment of the invention the inclination of the cutting disks of the disk shearer in the direction of mining transverse to the direction of cutting, as described by the determined differential angle, is taken into account during the establishment of a necessary cutting height adaptation.
With regard to an apparatus for carrying out the method described above, the radar sensors are set flushly into the surface of the main body of the disk shearer, so that as a result an exact value for the face opening can be measured. In order to respectively ensure the function of the radar sensors, pursuant to one specific embodiment of the invention a high pressure water rinsing device for the radar sensors is arranged on the main body of the disk shearer, and pursuant to a specific embodiment of the invention is time-controlled. Pursuant to an alternative embodiment, the high pressure water rinsing device can be event-controlled, i.e. for example the degree of fouling or dirt-accumulation is recognized, and when the dirt accumulation limits the precision of measurement, activation of the high pressure water rinsing device is effected. Pursuant to an alternative embodiment, for the cleaning of the radar sensors a mechanically operating scraping device can be provided. Here also a time-controlled or event-controlled activation of the scraping device can be provided. To the extent that with the embodiment described above the radar sensors that are disposed in the region of the surface of the main body of the disk shearer are disposed in the main dirt-accumulation region of the main body, to reduce the dirt accumulation alternatively the radar sensors can be disposed laterally on the path of travel side of the main body of the disk shearer, whereby the radar sensors can preferably be provided between the winches that are disposed on the main body of the disk shearer, and hence in a region that is also mechanically protected. With a view toward reducing the dirt accumulation, rather than providing the radar sensors with a “direction of view” that is perpendicularly upwardly relative to the top canopy of the shield support frame, the radar sensors can be disposed at an angle relative to the surface of the main body of the disk shearer, so that the thus inclined surface of the radar sensors is less susceptible to dirt. In the course of the evaluation of the signals received from the radar sensors, in such a case the measured longer path of the radar signals must be converted to a perpendicular distance between the upper edge of the main body of the disk shearer and the underside of the top canopy of the shield support frame.
To increase the precision of measurement, two radar sensors can be disposed on the main body of the disk shearer at a distance from one another and with a beam direction that is opposite to one another; in such a case, both signal transmission durations can be converted into the desired spacing or distance determination, and the distances resulting therefrom can be established in relationship to one another.

Specific embodiments of the invention are shown in the drawing, which is described subsequently and in which:

FIG. 1 is a schematic front view, seen in the direction of mining, of longwall equipment, including extraction machine and shield support frames illustrated only with their top canopies,

FIGS. 2 a-c are side views of the longwall equipment of FIG. 1 with an enlargement of the actual heights of the face opening carried out in two successive extraction travels, and

FIG. 3 is a schematic side view showing a shield support frame having inclination sensors disposed thereon.

As can be seen first of all from FIG. 1, a seam or layer 12, which is disposed between a roof or overlying stratum 10 and a footwall 11, is extracted by means of a disk shearer 13, which is provided with two cutting disks 16 a and 16 b that are mounted via support arms 15 on a main body 14 of the disk shearer. With a direction of movement of the disk shearer 13 along the seam 12, as is indicated by the arrow 17, the cutting disk 16 a operates as a leading cutting disk that cuts along the layer at the overlying stratum, while the cutting disk 16 b that cuts along the layer at the footwall operates as a trailing cutting disk. The overlying stratum portion of the seam 12 is supported by shield supports 25 (FIG. 2) that are oriented perpendicular to the direction of movement 17 of the disk shearer 13; only the top canopies 28 of the shield supports can be recognized in FIG. 1.
In order to measure the passage height between the upper edge of the main body 14 of the disk shearer and the underside of the top canopy 28 of the pertaining shield support 25 below which the main body travels during the extraction work, in other words below which the extraction work takes place, two radar sensors 18 are disposed on the main body set flushly in the upper surface of the main body 14; the radar sensors 18 emit signals perpendicularly and upwardly in the direction of the top canopies 28, and again receive the reflected signals, so that the distance between the top canopies 28 and the main body 14 can be determined in a straightforward manner, and in particular already early during the extraction travel of the disk shearer 13. In the illustrated embodiment, the two radar sensors 18 are disposed at the front and rear ends of the main body 14 respectively, and are set flushly into the upper surface of the main body. Although not illustrated, appropriate cleaning devices in the form of mechanical scrapers or high pressure water rinsing devices can be provided.
As can be further seen from FIG. 1, the thickness of the seam or layer 12, which is indicated by the arrow 19, is less than the minimum passage height of the longwall equipment indicated by the arrow 20, so that for the production or maintenance of the minimum passage height 20, the trailing cutting disk 16 b respectively carries out a cut 21 into the footwall.
If the passage height 22 (FIG. 2 a) that is determined by the use of the radar sensors 18 and is disposed between the top canopies 28 and the main body 14 of the disk shearer is known, it is possible therefrom in a straightforward manner to also determine the actual height of the face opening, since the distance between the upper edge of the main body 14 and the footwall 11 has a fixed value due to the steel construction comprised of the face conveyor 23 that rests upon the footwall and the disk shearer 13 that travels thereon.
As illustrated in FIG. 2 a, during the extraction work the passage height (arrow 22) between the top canopy 28 and the main body 14 is determined by the radar sensors 18, and from this the actual value of the face opening that exists between the overlying stratum 10 and footwall 11 can be determined. As can be seen from FIG. 2 a, the actual height of the face opening is less than the minimum passage height 20 of the longwall equipment, so that during each extraction travel, the trailing cutting disk 16 b must respectively carry out an additional cut into the footwall in order to step by step increase the overall height of the face opening that is cut free or exposed. As can be seen from a comparison of FIGS. 2 a, 2 b and 2 c, with two extraction travels, and hence with two cuts of the desired standard result, an establishment of the minimum passage 20 can be achieved. Since without any time delay the actual height of the face opening cut free during each extraction travel of the disk shearer 13 is determined, at the same time a brief rising of the footwall 11 due to convergence is also taken into account, since in each case extraction is dictated by the actual open height of the face that is cut free.
It can be seen in particular from FIG. 2 c that the face conveyor 23, and the disk shearer 13 that travels thereon, are after two steps already at the desired footwall level that corresponds to the desired target height of the face opening, while the shield frames 25, despite a corresponding bringing-up, are still at the original footwall level shown in FIG. 2 a. If consequently a control of the extraction work is oriented to a determination of the actual height of the face opening derived from the position of the shield support frames 25, this leads to false results or conclusions, because also in the position of the longwall equipment illustrated in FIG. 2 c, a height of the face opening determined at the shield support frames 25 is still classified as too low relative to the minimum passage height of the longwall equipment, with the result that further additional cuts into the footwall at the disk shearer 13 would be initiated in order to increase the supposedly still too low actual height of the face opening, although the target height of the face opening is already achieved starting with the position of the main body 14 of the disk shearer illustrated in FIG. 2 c.
Nevertheless, the face height control can be supplemented beyond the use of the radar sensors on the disk shearer 13, and can be checked and improved with respect to its control performance, by additionally carrying out a determination of the actual height of the face opening also in the region of the shield frame support 25. For this purpose, mounted on each shield support frame 25 are inclination sensors, so that it is possible merely on the basis of the geometrical conditions when the shield support frame 25 is used and which can be determined with a relatively small expenditure, to determine the face opening, in the form of the perpendicular height (h₁) that exists at the front end of the canopy 28.
As can be seen from FIG. 3, a shield support frame 25 is provided with a floor skid 26 on which are placed two parallel props 27, only one of which can be recognized in FIG. 3; at their upper ends, these props support a top canopy 28. While at its front (left) end the top canopy 28 projects in the direction of the disk shearer 13, at the rear (right) end of the top canopy 28 a gob shield 29 is hinged on by means of a joint 30, whereby as viewed from the side, the gob shield is supported by two supporting connection rods 31 that rest upon the floor skid 26. In the illustrated embodiment, mounted on the shield support frame 25 are three inclination sensors 32, in particular one inclination sensor 32 on the floor skid 26, one inclination sensor 32 in the rear region of the top canopy 28 in the vicinity of the joint 30, and one inclination sensor 32 on the gob shield 29. Although not illustrated, an inclination sensor can also be provided on the fourth moveable component of the shield support frame 25, namely the supporting connection rods 31, whereby of the four possible inclination sensors 32, in each case three inclination sensors must be installed in order to be able to determine with the inclination values determined thereby the position of the shield support frame in a working area. Furthermore, the inclination sensor 32 illustrated in the rear region of the top canopy 28 in FIG. 3 can be shifted to the front region of the canopy if a protected space is available in the canopy configuration. To this extent, the invention is not limited to the arrangement of the inclination sensors concretely illustrated in FIG. 3; rather, the invention includes all possible combinations of three inclination sensors on the four moveable components of the shield frame.
As furthermore indicated in FIG. 3, due to the known kinematics of the shield support frame 25, it is possible depending upon the position of the floor skid 26, the gob shield 29 and the top canopy 28 relative to one another to determine the heights h₁, h₂and h₃, whereby the height h₁is applicable for the determination of the perpendicular height of the face opening, whereas the height h₂forms a measure for a possible excessive height when the shield support frame is completely extended, or for a danger of superimposition or striking, while the height h₃can be used for the observation of the convergence. The determination of the heights h₁, h₂and h₃can be effected with the aid of the measurement values of the inclination sensors 17, whereby the values measured by these sensors 17 are compared in a non-illustrated computer with the base data stored therein for the geometrical orientation of the components and their movement characteristics relative to one another. For this purpose, the individual shield support frames 25 are calibrated into the longwall equipment after their installation by locating the position of the top canopy 28, the gob shield 29 and the floor skid 26 in the installed state by means of a manual inclinometer, and entering the measured values into the appropriate control of the shield support frame 25. To the extent that the height values h₁, h₂and h₃are represented in the shield control, these height values can be measured with measuring tapes and subsequently the inclination sensors can be correspondingly calibrated.
The features of the subject matter of these documents disclosed in the preceding description, the patent claims, the abstract and the drawings can be important individually as well as in any desired combination with one another for realizing the various embodiments of the invention.

Claims

1-21. (canceled)

22. A method for automated production of a defined face opening in longwall mining operations, in underground coal mining, comprising a face conveyor (23), a disk shearer (13) as an extraction machine, and a hydraulic shield support frame (25), the method including the steps of:

providing at least one radar sensor (18) on a main body (14) of said disk shearer (13);

measuring a distance (22) between an upper edge of said main body (14) of said disk shearer (13) and an underside of a top canopy (28) of said shield support frame (25) below which said main body (14) respectively travels during extraction work;

inputting this distance (22) into a computer as an actual value for a passage height (22) of said disk shearer (13) below said shield support frame (25);

comparing said actual value, in the computer, with a target value stored in the computer; and

if during said comparing step a deviation is determined, generating control commands for an adaptation of a cutting height of at least one of two cutting disks (16 a, 16 b) of said disk shearer (13).

23. A method according to claim 22, wherein the adaptation of the cutting height is undertaken at a conclusion of an extraction travel of said disk shearer (13) along the face.

24. A method according to claim 22, wherein the adaptation of the cutting height of said cutting disk (16 a, 16 b) is effected continuously as a reaction to the deviations determined in the computer.

25. A method according to claim 24, wherein a respective radar sensor (18) is disposed at opposite ends of said main body (14) of said disk shearer (13), and wherein that radar sensor (18) that is respectively toward the front as viewed in a direction of travel (17) is configured to deliver the actual value signals for the measured distance, or wherein signals received by both of said radar sensors (18) are continuously conveyed to the computer, where they are evaluated.

26. A method according to claim 25, wherein if it is determined that the passage height (22) measured by that radar sensor (18) that is toward the front in the direction of travel (17) deviates from the target value, immediately generating a control command for that cutting disk (16 a, 16 b) of the disk shearer (13) that is toward the rear in the direction of travel (17).

27. A method according to claim 22, which includes the further steps of comparing correction values for the cutting heights of said cutting disks (16 a, 16 b) established during successive extraction travels by respectively generated control commands with one another for adjustment purposes to determine from the correction values a total value, using this total value as a measure for a convergence that has commenced, and taking this total value into account during future extraction travels when a required cutting height adaptation is determined.

28. A method according to claim 22, which includes the further steps of providing inclination sensors (32) on at least three of the four main components of each shield support frame (25) selected from the group consisting of floor skid (26), gob shield (29), supporting connection rods (31), and that region of the top canopy (28) that is on the gob shield side; by means of said inclination sensors (32), determining the inclination of said shield support frame components relative to a horizontal in a direction of advancement; wherein from such measured data, in the computer, making a comparison with base data that is stored in the computer and that defines a geometrical orientation of the shield support frame components and their movement during advancement to calculate a respective perpendicular height (h₁) of said shield support frame (25) at the front end of said top canopy (28) as a measure for an actual face opening to determine actual values of the shield support frame height calculation; and conveying these thus determined actual values to the computer, which processes the actual values from the passage height measurement.

29. A method according to claim 28, wherein the actual values from the passage height measurement are converted into an actual face opening value taking into consideration an overall height of said top canopy (28) and the construction of said face conveyor (23) and said main body (14) of said disk shearer (13), and comparing said actual face opening value with the actual face opening value determined from the shield support frame height calculation for adjustment purposes.

30. A method according to claim 22, which includes the further step of determining an inclination of said face conveyor (23) and/or said disk shearer (13) relative to a horizontal in a direction of mining by means of inclination sensors mounted on said face conveyor (23) and/or on said disk shearer (13).

31. A method according to claim 30, which includes the further steps of setting an angle of inclination of said face conveyor (23) and/or of said disk shearer (13) in a relationship to an angle of inclination determined at said top canopy (28) of said shield support frame (25) and/or at a floor skid (26) of said shield support frame to form a differential angle, and taking this differential angle into account in the calculation of the actual face opening established during a plurality of successive advancement cycles of said shield support frame (25).

32. A method according to claim 31, which includes the step, during the establishment of a necessary cutting height adaptation, of taking into account an inclination of said cutting disk (16 a, 16 b) of said disk shearer (13) in a direction of mining transverse to a direction of cutting, which inclination of said cutting disk is prescribed by the determined differential angle.

33. An apparatus for carrying out automated production of a defined face opening in longwall mining operations in underground coal mining, comprising:

a face conveyor (23);

a disk shearer (13) as an extraction machine;

a hydraulic shield support frame;

two cutting disks (16 a, 16 b) disposed on said disk shearer (13);

at least one radar sensor (18) disposed on a main body (14) of said disk shearer (13), wherein said at least one radar sensor (18) is configured for measuring a distance (22) between an upper edge of said main body and an underside of a top canopy (28) of said shield support frame (25) below which said main body (14) respectively travels during extraction work, and wherein said at least one radar sensor (18) is set flushly into a surface of said main body (14) of said disk shearer (13); and

means for receiving and storing this distance (22) as an actual value for a passage height (22) of said disk shearer (13) below said shield support frame (25) for comparing this actual value with a target value stored in said means, and, if during the comparing action a deviation is determined, for generating control commands for an adaptation of a cutting height of at least one of said cutting disks (16 a, 16 b) of said disk shearer (13).

34. An apparatus according to claim 33, which further includes a high pressure water rinsing device for said radar sensors (18) arranged on said main body (14) of said disk shearer (13).

35. An apparatus according to claim 34, wherein said high pressure water rinsing device is time-controlled or event-controlled.

36. An apparatus according to claim 33, wherein a mechanically operating scraping device is disposed on said main body (14) of said disk shearer (13).

37. An apparatus for carrying out automated production of a defined face opening in longwall mining operations in underground coal mining, comprising:

a face conveyor (23);

a disk shearer (13) as an extraction machine;

a hydraulic shield support frame;

two cutting disks (16 a, 16 b) disposed on said disk shearer (13);

at least one radar sensor (18) disposed on a main body (14) of said disk shearer (13), wherein said at least one radar sensor (18) is configured for measuring a distance (22) between an upper edge of said main body and an underside of a top canopy (28) of said shield support frame (25) below which said main body (14) respectively travels during extraction work and wherein said at least one radar sensor (18) is disposed laterally on a path of travel side of said main body (14) of said disk shearer (13); and

38. An apparatus according to claim 37, wherein a position of said radar section of said radar sensors (18) is geared to an arrangement of winches provided on said main body (14) of said disk shearer (13).

39. An apparatus according to claim 37, wherein said radar sensors (18) are disposed at an angle relative to a surface of said main body (14) of said disk shearer (13).

40. An apparatus according to claim 39, wherein two radar sensors (18) are disposed on said main body (14) of said disk shearer (13) at a distance from one another and with a beam direction disposed opposite to one another.