AU2021272059A1

AU2021272059A1 - Extendable bootend

Info

Publication number: AU2021272059A1
Application number: AU2021272059A
Authority: AU
Inventors: Francis Attard; Shane McDowall
Original assignee: Dratta Eng Pty Ltd; Ksg Innovations Pty Ltd; Anglo American Metallurgical Coal Pty Ltd
Current assignee: Dratta Engineering Pty Ltd; Ksg Innovations Pty Ltd; Anglo American Metallurgical Coal Pty Ltd
Priority date: 2020-05-11
Filing date: 2021-05-11
Publication date: 2022-04-07
Also published as: CN216071836U; WO2021226659A1; CN113636294A

Abstract

An extendable bootend module for use in longwall mining, preferably in a series, between a mobile bootend and a belt conveyor to decrease the downtime of the mining operation due to stoppages to remove belt conveyor sections as a result of the advancement of the longwall; an extendable bootend system comprises one or more extendable bootend modules and a mobile bootend, and a method of operating the extendable bootend system.

Description

Extendable Bootend

Technical Field

[0001] The present disclosure relates to conveyor systems used in longwall mining, and specifically to conveyor systems used to transport material mined using a longwall system.

Background Art

[0002] A variety of different apparatuses exist for mining coal and other materials from underground seams. One apparatus that may be used in underground mining operations includes a mining machine used in instances where extended portions or longwalls of seam are to be mined. Such longwalls can be up to 2 kilometres long.

[0003] In longwall mining, the mined material may be cut or sheared in incremental shears (about 1 metre at a time) from the furthest part of the longwall forward towards the main mine tunnel. The mined material in each shear may be transported along a conveyor belt that runs along the longwall face (an armoured face conveyor) to a bream stage loader (BSL). The mined material may be transferred by the BSL onto a bootend which may be coupled to a fixed belt conveyor that conveyors the mined material further away from the longwall face. This belt conveyor generally runs perpendicular to the armoured face conveyor. At the outbye end of the belt conveyor may be yet another conveyor (the "life of mine" or "trunk" conveyor) that transports the mined materials to another location.

[0004] The conveyor system may be made up of a conveyor belt with a bootend at the inbye end (closest to the BSL) and a jib at the outbye end. The bootend may receive the mined material from the BSL, where it then travels along the conveyor belt to the jib and the life of mine conveyor.

[0005] As the longwall advances as material is sheared from the longwall surface, the location of the BSL and the bootend needs to advance accordingly so they can continue to be located proximate to the end of the longwall face. In existing systems, it is possible to advance the BSL over the bootend by approximately two metres (so approximately two shears of the longwall face). Beyond that point, the bootend itself needs to be moved. In order to have room for the bootend to be moved, a section of the conveyor belt needs to be removed. In a usual operation of the longwall process, this requires a conveyor belt section to be removed about every 4-5 hours.

[0006] In order to remove a section of the conveyor belt, it is necessary to stop the longwall mining process. The mining process is therefore stopped for about 20 minutes every 4-5 hours to remove the relevant section of the conveyor belt so the bootend can further advance. Although the replacement only takes about 20 minutes at a time, this adds up to about 4 hours a week, with the resulting downtime of the longwall mining machinery adding up to millions of dollar every week in lost production.

[0007] In this specification where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date, publicly available, known to the public, part of common general knowledge; or known to be relevant to an attempt to solve any problem with which this specification is concerned.

Summary

[0008] Disclosed herein is extendable bootend module for use in longwall mining, the extendable bootend module comprising: a length adjustable frame having an inbye end and an outbye end and a longitudinal axis extending between the inbye end and the outbye end, the length adjustable frame comprising: a first end structure at the inbye end of the length adjustable frame, a second end structure at the outbye end of the length adjustable frame, one or more retractable structures extending between the first end structure and the second end structure along the longitudinal axis, and a transportation portion extending along the first axis between the inbye end to the outbye end of the length adjustable frame to transport mined material from the inbye end to the outbye end. The extendable bootend module also comprises one or more module length adjustors which are operable to extend and/or retract the length adjustable frame, a module controller to direct the movement of the length adjustors, and one or more electronic module sensors to provide the module controller with information regarding the current length of the length adjustable frame.

[0009] In some forms, the first end structure further comprises a first connector engageable with a bootend and/or another extendable bootend module and the second end structure further comprises a second connector engageable with a belt conveyor system and/or another extendable bootend module.

[0010] In some forms, the module length adjustors comprise hydraulic cylinders, although other means may be used.

[0011] In some forms, the one or more electronic module sensors are reed rods, although other sensors may be used.

[0012] In some forms, the extendable bootend module also comprises extendable legs on either side of the length adjustable frame. Preferably, the extendable legs have stabilising elements which are operable to extend and retract the extendable legs. Preferably, the stabilising elements are hydraulic cylinders

[0013] In some forms, each of the extendable legs also have one or more electronic sensors to provide the module controllers with information regarding the length of each of the extendable legs. Preferably, each of the extendable legs have a reed rod that senses the length of the leg and an inclinometer to sense the angle of the leg with respect to the ground. Most preferably, the module controller will use this information to determine whether there is a need to extend or retract the hydraulic cylinders on the legs to raise or lower each of the extendable legs to stabilise the length adjustable frame.

[0014] Also disclosed herein is an extendable bootend system comprising an extendable bootend module as described above, and a mobile bootend. The mobile bootend comprises a body comprising an inbye end and an outbye end and a longitudinal axis extending between the inbye end and the outbye end, a receiving portion at the inbye end to receive mined materials from a base stage loader; a connector engageable with the extendable bootend module at the outbye end, and a transportation portion between the receiving portion and the connector to transport mined material to the extendable bootend module; wherein the connector of the bootend is engaged with the first connector of the extendable bootend module; and wherein the bootend extends along a common longitudinal axis to the extendable bootend module.

[0015] In some forms, the body further comprises a pivot table on which the receiving portion is slidable along the longitudinal axis between a minimum permitted location towards the inbye end of the body and a maximum permitted location towards the outbye end of the body.

[0016] In some forms, the body is a length adjustable body, and the bootend further comprises one or more bootend length adjustors which are operable to extend and/or retract the body, a bootend controller to direct the movement of the bootend length adjustors, and one or more electronic bootend sensors to provide the bootend controller with information regarding the position of the receiving portion in relation to the body of the bootend.

[0017] In some forms, the bootend length adjustors are hydraulic cylinders and the one or more electronic bootend sensors are reed rods. Alternatively, other sensors and means for adjustment may be used.

[0018] In some forms, the module controller and the bootend controller are connected by a wireless network. Alternatively, the connection may be wired.

[0019] Also disclosed herein is an extendable bootend system, as described above, and further comprising a series of connected extendable bootend modules in which each extendable bootend module is engaged at its first connector with another extendable bootend module at its second connector such that the extendable bootend system extends along a common longitudinal axis to form a row of extendable bootend modules that mined material can pass along.

[0020] In some forms where there is a single extendable bootend module, the extendable bootend system further comprises a belt conveyor system connected to the second connector of the extendable bootend module. In other forms where there is a series of extendable bootend modules, the extendable bootend system further comprises a belt conveyor system connected to the second connector of the extendable bootend module in the series of connected extendable bootend modules at the opposite end of the series to the mobile bootend.

[0021] Also disclosed herein is a method of operation of the extendable bootend system described above, when the mobile bootend is advanced a bootend distance. This method comprises detecting the bootend distance using the bootend sensors, determining a module distance, being the distance each module should retract to reflect a total retraction distance of the bootend distance, and retracting the module length adjustors the module distance for each module.

[0022] In some forms, the bootend controller and/or the module controllers determine the module distance Preferable, the module controllers then direct the retraction of the module length adjustors by the module distance. Alternatively, the bootend controller directs the retraction of the module length adjustors by the module distance.

[0023] In some forms, the module distance for each module is a distance between zero and the bootend distance. Preferably, the module distance for each module is the bootend distance divided by the number of modules.

[0024] In some forms, the method of operation of the extendable bootend system further comprises the steps of: detecting the length of the length adjustable frame for each module, determining whether the length adjustable frame has been retracted the module distance by comparing the length of the length adjustable frame with the length of the length adjustable frame prior to retraction of the module length adjustors by the module distance, and if the length adjustable frame has not been retracted the module distance, further retracting the module length adjustors for that module.

[0025] In some forms, the method further comprises the initial steps of: detecting the location of the receiving portion on the body of the bootend, comparing the location of the receiving portion with a predetermined maximum permitted location, and if the receiving portion is at the predetermined maximum permitted location, moving the mobile bootend the bootend distance in the outbye direction.

Brief Description of Drawings

[0026] Various embodiments/aspects of the disclosure will now be described with reference to the following drawings in which,

[0027] Figure l is a drawing of an extendable bootend module in accordance with a preferred embodiment of the present invention, showing the extendable bootend module in a fully retracted position. [0028] Figure 2 is a drawing of the extendable bootend module of figure 1, showing the extendable bootend module in a fully extended position.

[0029] Figure 3 is a drawing of a series of connected extendable bootend modules.

[0030] Figure 4 is a drawing of a bootend in accordance with a preferred embodiment of the present invention.

[0031] Figure 5 is a drawing of an extendable bootend system.

[0032] Figure 6 is a drawing of part a conveyor system including the extendable bootend system and part of the base stage loader and fixed belt conveyor

Detailed Description

[0033] In this specification, "inbye" refers to the direction closest to the site of mining and the forward end of operation, and "outbye" refers to the direction furthest from the site of mining, and the rearward end of operation .

[0034] An extendable bootend in accordance with the present disclosure will now be described with reference to Figures 1 to 5.

[0035] A extendable bootend module 1 as shown in Figures 1 and 2. The extendable bootend module 1 comprises a frame made up of a first end structure 2 at the inbye end of the frame, a second end structure 3 at the outbye end of the frame, the first end structure 2 and second end structure 3 connected by one or more retractable structures 4. The extendable bootend module 1 has two retractable structures, and each of those structures is a telescopic structure made up of a number of sub-structures of decreasing size such that each structure is able to nest (e.g. be seated, be supported) within the preceding sub -structure. Along the upper length of extendable bootend module 1 is the transportation portion of the frame which, in the detailed embodiment, consists of conveyor supports 5 and, in use, an endless conveyor belt on conveyor supports 5 (conveyor belt not shown). In use, the transportation portion will transport mined material from the inbye end of the frame to the outbye end of the frame.

[0036] Extendable bootend module 1 also includes length adjustors, shown in the detailed embodiment as hydraulic actuators (cylinders) 6. In the detailed embodiment, the extendable bootend module 1 includes two hydraulic cylinders 6 which are each located between first end structure 2 and second end structure 3. The hydraulic actuators 6 and the connected between the hydraulic actuators 6 and the structures 4 are configured such that, when the actuators 6 retract or extend, the actuators 6 have the effect of retracting or extending retractable structures 4 by the same amount.

[0037] Extendable bootend module 1 further comprises one or more sensors, shown as reed rods 7 in the detailed embodiment. In the detailed embodiment, there are two reed rods 7 and they are each located between first end structure 2 and second end structure 3. Each reed rod 7 is made up of two parts, with the second part of decreased size such that it can nest within the first part. Sensors within reed rod 7 allow it to ascertain the length of the reed rod 7 and therefore the current length of retractable structures 4.

[0038] Extendable bootend module 1 further comprises module controller 8. Module controller 8 is in wireless communication with both hydraulic cylinders 6 and reed rods 7. In the detailed embodiment shown in Figures 1 and 2, module controller 8 is located on extendable bootend module 1, although it may also be located separately to the extendable bootend module 1. One or both reed rods 7 provide module controller 8 with information to determine the length of retractable structures 4. Module controller 8 then compares the information from reed rods 7 with a desired length of the retractable structures, and outputs instructions to the hydraulic cylinders 6 (i.e. to retract or extend).

[0039] On the inbye end of first end structure 2 is first connector 9, which is configured to engage a corresponding connector on a mobile bootend 10 (see Figure 5) or another extendable bootend module 1 (see Figure 3). On the outbye end of second end structure 3 is second connector 11. Second connector 11 is configured to engage the fixed belt conveyor 12 (see Figure 6) or another extendable bootend module 1. In this way, a number of extendable bootend modules 1 are able to be connected to one another to form a series of extendable bootend modules 1 that extend between the outbye end of mobile bootend 10 and the inbye end of fixed belt conveyor 12 (see Figure 6). For example, in the detailed embodiment shown in Figure 3, the series of extendable bootend modules 1 includes four extendable bootend modules 1. Extendable bootend modules 1 are connected to each other, to mobile bootend 10 and to the belt conveyor 12, via a pinned connection mounting arrangement. [0040] Extendable bootend module 1 further comprises extendable legs 13 on either side of second end structure 3. Extendable legs 13 further comprise stabilising elements, shown in the detailed embodiment as hydraulic actuators (cylinders) 14, which are operable to extend and retract the extendable legs. Each extendable leg 13 further comprises electronic sensors, in the form of a reed rod (not shown) and inclinometer (not shown).

[0041] The Reed rod detects the length of extendable leg 13 and provides that information to module controller 8. Module controller 8 then compares the information from reed rod with the currently desired length of extendable leg 13, and directs the retraction or extension of hydraulic cylinders 14 as required.

[0042] Inclinometer detects the angle of extendable leg 13 with respect to the ground and provides that information to module controller 8. The module controller 8 uses that information to determine if extendable bootend module 1 is level. By ensuring that the extendable bootend module 1 is level, it is possible to ensure the effective transport of mined material along transportation portion 5.

[0043] Mobile bootend 10 in the extendable bootend system has a body 11 having a receiving portion 18 at the inbye end of the body, which, in use, receives mined material from base state loader 22 which is located over receiving portion 18 of mobile bootend 10. Receiving portion 18 is slidable on body 11 by way of pivot table 19, which permits receiving portion 18 to be located at a number of different locations with respect to body 11. By way of sliding along pivot table 11, receiving portion 18 can be located to receive mined material from base stage loader 22 when base stage loader 22 is advanced one or more times without having to move mobile bootend 10 every time that the base stage loader 22 is advanced. At the outbye end of mobile bootend 10 is connector 20 which is engageable with the first connector 9 of the extendable bootend module 1. Extending along the upper length of mobile bootend 10 from the inbye end to the outbye end is the transportation portion which, in the detailed embodiment, consists of pigs trough 21. In use, receiving portion 18 is located underneath, and receives mined material from, base stage loader 22 (see Figure 6). The mined material is then transferred to the outbye end of the mobile bootend 10 via pigs trough 21 for transport onto the connected extendable bootend module 1. [0044] In the detailed embodiment, mobile bootend 10 has extendable legs 23 similar to those of extendable bootend module 1. Extendable legs 23 are located on either side of connector 20 and comprise stabilising elements, shown in the form of hydraulic actuators (cylinders) 24, configured to extend and retract extendable legs 23, and electronic sensors, in the form of reed rods and inclinometers.

[0045] Reed rods 25 detect the length of extendable legs 23 and provides that information to bootend controller 27. Bootend controller 27 then compares the information from reed rods 25 with the currently desired length of extendable legs 23, and directs the retraction or extension of hydraulic cylinders 24 as required.

[0046] Inclinometers detect the angle of extendable legs 23 with respect to the ground and provides that information to bootend controller 27, where bootend controller 27 uses that information to determine if mobile bootend 10 is level.

[0047] In the detailed embodiment shown in Figures 1 and 2, bootend controller 27 is located on mobile bootend 10, although it may also be located separately to extendable mobile bootend 10. In either embodiment, bootend controller is wirelessly connected to the reed rods 25, the inclinometers and hydraulic cylinders 24.

[0048] In the detailed embodiment, mobile bootend 10 also comprises length adjustors, shown as hydraulic actuators (cylinders) 28, and electronic bootend sensors, in the form of reed rods. Bootend controller 27 is also wirelessly connected to hydraulic cylinders 28 and reed rods 29.

[0049] Receiving portion 18 has a maximum and minimum permitted location with respect to body 11, each of which are predetermined locations. At the minimum permitted location, receiving portion 18 will be located towards the inbye end of body 11. At the maximum permitted location, receiving portion 18 will be located towards the outbye end of body 11.

[0050] At the start of operation of the extendable bootend system, mobile bootend 10 will be located so that receiving portion 18 is at its minimum permitted location.

[0051] Each sheer of the longwall will result in base stage loader 22 advancing a distance over mobile bootend 10. In general operations, this distance is approximately one metre. The movement of receiving portion 18 on pivot table 19 along body 11 is registered by reed rods 29. The information from reed rods 29 is sent to bootend controller 27, which will compare that information to the predetermined maximum and minimum permitted locations of receiving portion 18. If receiving portion 18 is not at the maximum permitted location, mobile bootend 10 will remain where it is. If receiving portion 18 is at the maximum permitted location, the mobile bootend will be advanced a predetermined distance away from base stage loader 22, referred to as the bootend distance, and receiving portion 18 returned to its minimum permitted distance. This movement is by hydraulic cylinders 24 extending to advance the outbye end of mobile bootend 10 forward in an outbye direction, and then retracting to advance the inbye end of mobile bootend 10 forward in the outbye direction.

[0052] In the detailed embodiment, the distance between the minimum and maximum permitted locations of receiving portion 18 is two sheers of the longwall (approximately two metres) and the bootend distance is also the distance of two sheers of the longwall.

[0053] When mobile bootend 10 is advanced the bootend distance, the extendable bootend module(s) needs to be retracted a corresponding amount, as it is connected at its outbye end to a fixed belt conveyor.

[0054] When bootend controller 27 determines that the bootend needs to be advanced a bootend distance, bootend controller 27 will also determine the distance that the extendable bootend module(s) 1 needs to be advanced (referred to as the module distance). Bootend controller 27 will then direct hydraulic cylinders 6 via module controllers 8 to retract the module distance, with reed rods 7 ensuring that hydraulic cylinders 6 retract the appropriate distance, at the same time as directing the advancement of mobile bootend 10. In an alternative embodiment, bootend controller 27 may direct the movement of hydraulic cylinders 6, and receive information from reed rods 7, without the need for module controllers 8.

[0055] Where there is a single extendable bootend module 1, the module distance will be the same as the bootend distance. Where there is a series of extendable bootend modules 1 (as in the detailed embodiment), the module distance for each extendable bootend module 1 will be a distance between zero and the bootend distance, with the sum of the module distances for each extenable bootend module equalling the bootend distance.

[0056] In one embodiment, only one extendable bootend module 1 will retract for any given movement of mobile bootend 1. In this embodiment, the module distance for one extendable bootend module 1 will be the bootend distance, and the module distance for the remaining extendable bootend modules 1 will be zero.

[0057] In another embodiment, each of the extendable bootend modules will retract an equal distance for any given movement of mobile bootend 1. In this embodiment, the module distance for each extendable bootend module 1 will be the bootend distance divided by the number of extendable bootend modules.

[0058] The cycle of movement of mobile bootend 10 and retraction of extendable bootend module(s) 1 will continue until the one or more extendable bootend modules 1 are in the fully retracted position, as shown in figure 1. Mobile bootend 10 will then push forward the fully retracted extendable bootend module(s) 1 until no further movement is possible without removal of a section of fixed belt conveyor 12. In a preferred embodiment, the outbye end of extendable bootend module closest to belt conveyor 12 will have a limit switch 30 which is engageable with fixed bent conveyor 12. When the limit switch engages with fixed belt conveyor 12, it sends a signal to bootend controller 27, which determines that the mobile bootend cannot travel further and sends a signal to hydraulic cylinders 28 to immediately stop further advancement of mobile bootend 10.

[0059] Once advancement of mobile bootend 10 is stopped, a section of fixed belt conveyor 12 will be removed, preferably a section equivalent to the total length of the extendable bootend modules. The extendable bootend module(s) will then be expanded so that the most outbye extendable bootend module meets and is engageable with the inbye end of fixed belt conveyor 12. It is then connected with fixed belt conveyor 12.

[0060] When the extendable bootend module(s) reaches its fully expanded position (as shown in Figure 2) or otherwise bridges the gap between the outbye end of the extendable bootend system and the fixed belt conveyor, the information from reed rods 15 and inclinometers 16 will be used by module controller 8 to determine the appropriate length of extendable legs 13, and extend or retract hydraulic cylinders 14 accordingly. The process of advancement of mobile bootend 10 and the retraction of extendable bootend module(s) 1 will then recommence.

[0061] By use of the extendable bootend system, the time between shutdowns for removal of a section of the fixed belt conveyor is greatly increased from every 4-5 hours to a much increased number of hours, depending on the length of each extendable bootend module, and the number of extendable bootend modules used. The decreased downtime in the longwall mining process over a day, and over a week, means that more material can be mined, with a resulting increase in revenue.

[0062] The word ‘comprising’ and forms of the word ‘comprising’ as used in this description and in the claims does not limit the invention claimed to exclude any variants or additions.

[0063] Modifications and improvements to the invention will be readily apparent to those skilled in the art. Such modifications and improvements are intended to be within the scope of this invention.

Claims

Claims

1 An extendable bootend module for use in longwall mining, the extendable bootend module comprising: a length adjustable frame extending along a longitudinal axis between an inbye end and an outbye end, the length adjustable frame comprising: a first end structure at the inbye end of the length adjustable frame; a second end structure at the outbye end of the length adjustable frame; one or more retractable structures extending substantially parallel to the longitudinal axis between the first end structure and the second end structure; and a transportation portion extending substantially parallel to the longitudinal axis between the inbye end and the outbye end of the length adjustable frame, the transportation portion being configured to transport mined material from the inbye end to the outbye end; one or more module length adjustors, the one or more module length adjustors being configured to extend and retract a length of the length adjustable frame; a module controller in communication with the one or more module length adjustors to extend and retract the one or more module length adjustors; and one or more module sensors in communication with the module controller, the one or more module sensors being configured to provide the module controller with information regarding the length of the length adjustable frame.

2 The extendable bootend module of claim 1, wherein the first end structure comprises a first connector engageable with a bootend and/or another extendable bootend module and the second end structure comprises a second connector engageable with a belt conveyor system and/or another extendable bootend module.

3 The extendable bootend module of claim 1 or 2, wherein the one or more module length adjustors comprise hydraulic actuators.

4 The extendable bootend module of any one of claim 1 to 3, wherein the one or more module sensors comprise a reed rod.

5 The extendable bootend module of any one of claims 1 to 4, further comprising extendable legs disposed on either side of the length adjustable frame. 6 The extendable bootend module of claim 5, wherein each extendable leg comprises a stabilising element configured to extend and retract the extendable leg.

7 The extendable bootend module of claim 6, further comprising one or more sensors associated with each of the extendable legs, the one or more sensors being configured to provide the module controller with information regarding a length of each of the extendable legs.

8 The extendable bootend of claim 7, wherein the module controller is configured to determine whether the stabilising elements need to raise or lower each of the extendable legs to stabilise the length adjustable frame based on information received from the one or more sensors associated with the extendable legs.

9 An extendable bootend system comprising an extendable bootend module in accordance with any one of claims 1 to 8, and a mobile bootend, the mobile bootend comprising: a body extending along a longitudinal axis of the body between the an inbye end and an outbye end of the body, the body comprising; a receiving portion disposed at the inbye end to receive mined materials from a base stage loader; a connector disposed at the outbye end, the connector being configured to engage the extendable bootend module at the outbye end; and a transportation portion disposed between the receiving portion and the connector to transport mined material to the extendable bootend module; wherein the connector of the mobile bootend is engaged with the first connector of the extendable bootend module; and wherein the mobile bootend extends along a common longitudinal axis to the extendable bootend module.

10 The extendable bootend system of claim 9, wherein the body further comprises a pivot table on which the receiving portion is slidable along the longitudinal axis of the body between a minimum permitted location towards the inbye end of the body and a maximum permitted location towards the outbye end of the body.

11 The extendable bootend system of claim 9 or 10, wherein the body is a length adjustable body, the mobile bootend further comprising: one or more bootend length adjustors operable to extend and retract the body; a bootend controller configured direct movement of the bootend length adjustors; and one or more bootend sensors in communication with the bootend controller and configured to provide the bootend controller with information regarding a position of the receiving portion in relation to the body.

12 The extendable bootend system of claim 11, wherein the bootend length adjustors comprise hydraulic actuators.

13 The extendable bootend system of claim 10 or 11, wherein the one or more bootend sensors comprise a reed rod.

14 The extendable bootend system of any one of claims 11 to 13 wherein the module controller and the bootend controller are connected by a wireless network.

15 The extendable bootend system of any one of claims 9 to 14, further comprising a series of connected extendable bootend modules in which each extendable bootend module is engaged at its first connector with another extendable bootend module at its second connector such that the extendable bootend system extends along a common longitudinal axis.

16 The extendable bootend system of any one of claims 9 to 14, further comprising a belt conveyor system connected to the second connector of the extendable bootend module.

17 The extendable bootend system of claiml5, further comprising a belt conveyor system connected to the second connector of the extendable bootend module in the series of connected extendable bootend modules at the opposite end of the series to the mobile bootend.

18 A method of operating the extendable bootend system of any one of claims 9 to 17 when the mobile bootend is advanced a bootend distance, the method comprising: detecting the bootend distance using the bootend sensors; determining a module distance, being the distance each module should retract to reflect a total retraction distance of the bootend distance; retracting the module length adjustors the module distance for each module.

19 The method of claim 18, wherein the bootend controller and/or the module controllers determine the module distance. 20 The method of claim 18 or 19, wherein the module controllers direct the retraction of the module length adjustors by the module distance.

21 The method of any one of claims 18 to 20, wherein the module distance for each module is a distance between zero and the bootend distance.

22 The method of any one of claims 18 to 20, wherein the module distance for each module is the bootend distance divided by the number of modules.

23 The method of any one of claims 18 to 22, further compromising the steps of: detecting the length of the length adjustable frame for each module; determining whether the length adjustable frame has been retracted the module distance by comparing the length of the length adjustable frame with the length of the length adjustable frame prior to retraction of the module length adjustors by the module distance; if the length adjustable frame has not been retracted the module distance, further retracting the module length adjustors for that module.

24 A method of operating the extendable bootend system of any one of claims 9 to 17, the method comprising the steps of any one of claims 18 to 23, and further comprising, as initial steps: detecting the location of the receiving portion on the body of the bootend; comparing the location of the receiving portion with a predetermined maximum permitted location; if the receiving portion is at the predetermined maximum permitted location, moving the mobile bootend the bootend distance in the outbye direction.