WO2025239805A1

WO2025239805A1 - Drill arrangement and method

Info

Publication number: WO2025239805A1
Application number: PCT/SE2024/050463
Authority: WO
Inventors: Patrik Larsson; Wille LEIJONMARCK; Jon ÅKEFELDT
Original assignee: Epiroc Rock Drills AB
Current assignee: Epiroc Rock Drills AB
Priority date: 2024-05-14
Filing date: 2024-05-14
Publication date: 2025-11-20
Anticipated expiration: 2026-11-14

Abstract

Drill arrangement (101 ) and method for cutting a drill rod (125). The drill arrangement (101) comprises a drill rod (125), drill driving means (106) arranged to drive the drill rod (125) in a longitudinal axis direction (LA) and into a material to be drilled, detection means arranged to detect whether the drill rod (125) is stuck in the material to be drilled and cannot be retracted from the same, a drill rod cutter (20), arranged for cutting the drill rod (125), and a control unit arranged to trigger the drill rod cutter (20) to cut off the drill rod (125) in response to the detection means detecting that the drill rod is stuck in the material to be drilled and cannot be retracted from the same. The method comprises detecting (1001) whether the drill rod (125) is stuck, triggering (1003) a cutting off operation, in response to detecting (1001) that the drill rod is stuck and cutting off (1005) the drill rod (125), by the drill rod cutter (20).

Description

DRILL ARRANGEMENT AND METHOD

Technical field

[0001] The present disclosure relates to a drill arrangement with a drill rod cutter arranged at a drill arrangement. It further relates to a method for cutting a drill rod at a drill arrangement. Preferably, the drill arrangement and the method concern a drill arrangement within mining industry.

Background

[0002] Mining can be carried out by so called raise caving which is a mining method where the mining starts from the bottom of a shaft and moves upwards. Raise caving can be performed down to several thousands of meters in vertical or inclined shafts. The raise caving operation starts by boring the shafts, which are then widened from the bottom to the top and is performed by using a drill arrangement to drill holes at the lowest level of the shaft, charging the holes with blasting agent, and blasting away the rock. Those steps are repeated, moving upwards in the shaft. Hence, drill patterns and movements of the drill arrangement and the equipment used for filling drill holes with blasting agent are complicated and are to be performed at several thousands of meters depth. Remotely controlled drill arrangements are therefore developed to facilitate movement of the drilling arrangement down to the drill level and the drill arrangements are further able to move the drill equipment with high precision once it is located at the drill level. Such a solution is invented by the applicant and is presented in the patent application WO 2024/096771 A1. This patent concerns a drill arrangement which comprises a drill equipment and a drill adjuster, wherein the drill equipment is arranged to be operationally connectable to a platform via the drill adjuster and the drill equipment is tiltably connected to the drill adjuster so that the drill equipment is tiltable with respect to the drill adjuster about a pivot axis PA. The drill adjuster is arranged to be rotatably connectable to the platform so that the drill adjuster is rotatable with respect to the connectable platform around a rotational axis RA extending perpendicularly to the pivot axis PA and the drill equipment comprises a drill which extends along a longitudinal axis LA, and the longitudinal axis LA, the pivot axis PA and the rotational axis RA intersect in a common centrum point CP. Further, the disclosure relates to a method for drilling holes in a vertical or an inclined shaft.

[0003] Some remotely operated drill arrangements need to solve all problems that may occur remotely, since no person is, first of all, allowed to be in the vertical or inclined shafts and secondly, it is not even possible for a person to be near the drill arrangement at such locations. When drilling in the rock, several drill rods are connected to each other to form a drill string, to be able to drill deeper into the rock. The drill string is fed forward during drilling by a feeder of the drill arrangement and everything is operated remotely. One problem that may occur is that a drill rod of the drill string may get stuck, and by that make the complete drill arrangement to stop and also get stuck, if one cannot solve the problem. Thus, there is a need of taking care of that problem.

Summary

[0004] It is an object of the disclosure to address at least some of the problems and issues outlined above.

[0005] According to one aspect, a drill arrangement is disclosed. The drill arrangement comprises a drill rod which extends along a longitudinal axis, drill driving means, which are arranged to drive the drill rod in a direction of the longitudinal axis, and into a material to be drilled (rock face/cave wall/drift wall). The drill arrangement further comprises detection means, which are arranged to detect whether the drill rod is stuck in the material to be drilled and cannot be retracted from the material to be drilled. The detections means may for example be arranged to detect hydraulic pressure of a drill driving motor (driving the rotation of the drill rod) or for example detect the drive pressure of a drill feeder or the like. Further, the drill arrangement comprises a drill rod cutter, arranged for cutting the drill rod, and a control unit, arranged to trigger the drill rod cutter to cut off the drill rod in response to the detection means detecting that the drill rod is stuck in the material to be drilled and cannot be retracted from the material to be drilled. [0006] By such a drill arrangement, any application, even remotely operated drill arrangements, can be released from a drill hole by cutting off the drill rod, wherein the drill equipment can be retrieved and/or reloaded with a new drill for further in connection to the drill arrangement. For example, in raise caving, a jammed drill might jeopardize the complete drill arrangement, which might be lost if the drill cannot be released from the jammed position in the drill hole, which leads to high costs and waste. Also in other applications, where it might be dangerous to be near the drill area, or for other reasons, personnel might not be able to approach the drill area, the possibility of remotely cut the drill rod is of great value. The detection means may trigger a warning signal wherein an operator may trigger the cutting off operation of the drill rod, or the control unit may initialize an automatic cutting off operation based on that the drill rod is detected as stuck in the material to be drilled and cannot be retracted from the same. This is a very useful function which is not previous known within mining or other rock drilling operations.

[0007] According to an embodiment, the control unit is arranged to inform a central control unit that the detecting means has detected that the drill rod is stuck and to await until an instruction from the central control unit to cut off the drill rod is received, before triggering the cutting off, of the drill rod. This functions as an extra control step before the cutting off operation.

[0008] According to an embodiment, the control unit is to wait a predetermined time period after the detection unit detected that the drill rod is stuck before triggering cut off the drill rod. This, to avoid unnecessary cutting off of the drill rod until a check might be done, which may be a visual check by the operator, by a camera or other type of check or action to be taken before the cutting off operation.

[0009] According to an embodiment, the control unit is arranged to inform the central control unit that the detecting means has detected that the drill rod is stuck, by transmitting information remotely via wireline or wireless communication and to receive the instruction to cut off the drill rod from the central control unit via the wireline or wireless communication. [0010] According to an embodiment, the drill rod cutter is arrangeable in a resting position and a cutting position, wherein when the drill rod cutter is triggered to cut off the drill rod, the drill rod cutter is moved from the resting position to the cutting position. In this way, the drill rod cutter is out of way during normal drilling operation by the drill arrangement.

[0011] According to an embodiment, the drill rod cutter comprises a saw, arranged substantially perpendicular to the drill rod, when it is to cut the drill rod. A saw is a robust and reliable tool suitable for the cutting of operation.

[0012] According to an embodiment, the saw of the drill rod cutter is pivotally arranged at the drill arrangement such that the saw is pivotable between the resting position and the cutting position.

[0013] According to an embodiment, the drill rod cutter comprises a mechanical lock with a locking function, which prevents the drill rod cutter from moving from the resting position to the cutting position. The mechanical lock functions as a safety lock which prevents the cutter from accidentally move from the resting position to the cutting position.

[0014] According to an embodiment, the drill rod cutter further comprises an operating means arranged to control a cutting operation of the cutting of the drill rod and which operating means, when the drill rod cutter is triggered to cut off the drill rod, is arranged to move the drill rod cutter from its resting position to its cutting position.

[0015] According to an embodiment, the operating means is a hydraulic cylinder, and the drill rod cutting operation is controlled by controlling the hydraulic pressure of the hydraulic cylinder, wherein, when the hydraulic pressure of the hydraulic cylinder increases relative a pressure in which the drill rod cutter is in its resting position, the hydraulic cylinder extends and by that a pressure is applied on the drill rod cutter, wherein the drill rod cutter moves from the resting position to the cutting position. By the hydraulic cylinder, the both the movement from the resting position to the cutting position is controlled as well as the pressure force for cutting off the drill rod may be controlled by controlling the pressure of the hydraulic cylinder.

[0016] According to an embodiment, when the operating means is a hydraulic cylinder, and when the hydraulic cylinder extends, the locking function of the mechanical lock ceases and the drill rod cutter moves from its resting position towards its cutting position. By that, when cutting off is initialized, the mechanical lock is released by the operating means.

[0017] According to an embodiment, the drill rod cutter further comprises a frame, which is arranged for fixed connection of the drill rod cutter to the drill arrangement, a motor, fixedly arranged at the frame. The motor is attached to a shaft which extends in the longitudinal axis direction, wherein the motor is arranged to rotate the shaft. The shaft comprises a disc, which is fixedly attached with its center to an end of the shaft, perpendicular to the shaft, and the saw is pivotally arranged at the frame and comprises a saw blade and a bow part. The bow part comprises a first end and an opposite second end, wherein the saw blade is attached between the first end and the second end of the bow part. The first end of the bow part is pivotally attached to a periphery of the disc via a link arm. By this arrangement, the rotational movement of the motor and shaft is transferred to the disc and further to a sawing motion of the saw. When a drill rod is detected as stuck in the rock, the cutting off operation is initiated, the motor is started and the operating means starts to move the drill rod cutter (the saw) from the resting position to the cutting off position, wherein the drill rod is start to get cut by a sawing motion and by a pressure controlled by the operating means, until the drill rod is cut off. When the drill rod is cut off, the system may detect that the drill rod is cut off, for example by the pressure in the hydraulic cylinder or a sensor for detection of the completed operation, visual inspection by operator directly or via camera, etc.

[0018] According to a disclosure, a method for cutting a drill rod at a drill arrangement, according to any embodiment described above, is disclosed. The method comprises

- detecting whether the drill rod is stuck in the material to be drilled and cannot be retracted from the material to be drilled,

- triggering a cutting off operation, in response to detecting that the drill rod is stuck in the material to be drilled and cannot be retracted from the material to be drilled,

- cutting off, by the drill rod cutter, the drill rod.

The method may preferably be used during drilling in a vertical or an inclined mine shaft, especially in connection to raise caving but may also be used if the drill arrangement is for some reason inaccessible.

[0019] According to an embodiment, the triggering of the drill rod cutter to cut off the drill rod is performed after a predetermined period of time.

[0020] According to an embodiment, the triggering of the drill rod cutter to cut off the drill rod is performed remotely.

[0021] According to an embodiment, the cutting off comprises:

- moving the drill rod cutter from a resting position to a cutting position, by an operating means,

- applying a pressure force on the drill rod cutter by the operating means.

[0022] According to an embodiment, when the operating means is a hydraulic cylinder, the method further comprises:

- the cutting off comprises increasing a pressure in the hydraulic cylinder, for moving the drill rod cutter from the resting position to the cutting position and for applying the pressure force on the drill rod cutter.

[0023] According to an embodiment, the method further comprises:

- controlling the pressure in the hydraulic cylinder during the cutting off operation.

[0024] According to an embodiment, when the drill rod cutter comprises a saw, the method further comprises:

- the cutting off comprises starting a motor arranged to drive a back and forth motion of the saw, and

- the applying of a pressure force on the drill rod cutter by the operating means comprises applying a pressure on the saw by the operating means. [0025] According to an embodiment, the method is a method for raise caving.

[0026] Further possible features and benefits of this solution will become apparent from the detailed description below.

Brief description of drawings

[0027] The invention is now described, by way of example, with reference to the accompanying drawings, in which:

[0028] Fig. 1 shows a side view of a drill arrangement of the type arranged for raise caving, which comprising an inventive drill rod cutter, symbolically shown as a rectangular box to right of the drill rod, close to the rock shaft surface.

[0029] Fig. 2 shows a perspective view of the drill arrangement of Fig. 1.

[0030] Fig. 3a shows perspective view of a feed beam of the drill arrangement, seen from a front end, onto which feed beam the inventive drill rod cutter is arranged at a front end of the feed beam.

[0031] Fig. 3b shows perspective view of the feed beam of Fig. 3a, seen from a back end, wherein a back side of the inventive drill rod cutter is visible.

[0032] Fig. 4a shows a perspective view of the drill rod cutter, where a cutting tool, i.e. a saw, is in a resting position.

[0033] Fig. 4b shows a perspective view of the drill rod cutter, where the cutting tool, i.e. a saw, is in a in a cutting position.

[0034] Fig. 5 shows a flow chart over an inventive method for cutting the drill rod at the drill arrangement according to the invention.

Detailed description

[0035] In the following, different examples of a drill rod cutter according to the invention, is disclosed. The method disclosed herein may be realized in many different forms and should not be construed as being limited to the examples set forth herein. Like numbers in the drawings refer to like elements throughout. [0036] Fig. 1 shows a drill arrangement 101 which is lowered into a mine shaft 120 with shaft walls 121. Fig. 2 shows a perspective view of the drill arrangement 101 in the mine shaft 120. The drill arrangement 101 comprises a drill equipment 103 and a drill adjuster 104. The drill equipment 103 is arranged to be operationally connectable to a platform 102 via the drill adjuster 104. The drill equipment 103 is tiltably connected to the drill adjuster 104 so that the drill equipment 103 is tiltable with respect to the drill adjuster 104 about a pivot axis PA (see Fig. 2). By this construction it will be possible to drill holes 109 into the shaft wall 121 of the rock shaft 120, which holes 109 extends in several directions around the shaft. Further, the drill adjuster 104 is arranged to be rotatably connectable to the platform 102 so that the drill adjuster 104 is rotatable with respect to the platform 102 around the rotational axis RA extending perpendicularly to the pivot axis PA (see Fig. 2). Further, the drill equipment 103 comprises a drill driving means/drill 106, which extends along a longitudinal axis LA, and the longitudinal axis LA, the pivot axis PA and the rotational axis intersect in a common centrum point CP (see Fig. 2). The drill 106 may be a percussion drill or a rotation drill or other types of drills and the drill equipment 103 may comprise a drill rod feeding device 114, which comprises several drill rods 125 to be used during the drilling. When drilling in the rock, several drill rods 125 may be connected to each other to form a drill string, to be able to drill deeper holes 109 into the rock. The drill / drill string is fed forward during drilling by the drill driving means/drill 106. The latter is arranged on a feed beam 113 which extends in parallel with the longitudinal axis LA and everything is operated remotely. Fig. 2 shows the drill arrangement 101 without the platform 102, in a perspective view.

[0037] The functionality and technical details concerning the drill equipment 103, the drill adjuster 104, the platform 102 etc. related to Figs. 1 and 2 are described in detail in WO 2024/096771 A1. The invention concerns the drill arrangement 101 complemented by a drill rod cutter 20 as will be explained below.

[0038] Fig. 3a shows perspective view of the feed beam 113 of the drill arrangement 101 , seen from a front end of the feed beam 113, with the drill rod cutter 20 fixedly arranged at a front end 113a of the feed beam 113. The front end 113a is opposite a back end 113b of the feed beam 113. Fig. 3b shows perspective view of the feed beam 113, seen from a back end, with the drill rod cutter 20 visible at its front end 113a. The drill 106, is in the figures removed for better visibility. A cradle 108, which carries the drill 106 is slidably arranged at the feed beam 113, which can be seen close to the back end 113b of the feed beam 113. By that, the drill 125 may be pushed forwards in the drill direction, which is the same as the longitudinal axis direction LA. As an alternative or as a added choice, and depending on the type of drill arrangement 101 , the feed beam 113 may be extendable and retractable.

[0039] As explained above, one problem that may occur is that a drill rod 125 or the drill string may get stuck in the bore hole 109, and by that make the complete drill arrangement 101 to stop and also get stuck. That’s why the inventive drill rod cutter 20 is invented. The drill rod cutter 20 comprises a frame 24 and a saw 22 (see further Figs. 4a-b), wherein the saw 22 is driven by a motor 25. Preferably, the motor 25 is a hydraulic motor. The saw 22 is protected by that the frame 24 is arranged as a cover, protecting the saw 22 from being directly hit by stones or other down falling parts of the rock. The frame 24 is fixedly attached to the front end 113a of the feed beam 113.

[0040] Fig. 4a shows a perspective view of the drill rod cutter 20, where the saw 22 of the drill rod cutter 20 is in a resting position A, where the saw 22 is in a ready state, ready for a cutting operation (the drill rod is removed for better visibility). Fig. 4b shows a perspective view of the drill rod cutter 20 when the saw 22 is in a cutting position B, in which it is cutting the drill rod 125 if the drill rod 125 is stuck in the material to be drilled (i.e. in the hole of the rock). The drill arrangement 101 comprises detection means (not visible), which are arranged to detect whether the drill rod 125 is stuck in the material to be drilled and cannot be retracted from the material to be drilled. The drill arrangement 101 also comprises a control unit (not visible) which is arranged to trigger the drill rod cutter 20 to cut off the drill rod 125, in response to the detection means detecting that the drill rod 125 is stuck in the bore hole/the material of the rock (which is drilled), by means of the saw 22. The control unit may comprise a processor and a memory. The memory may contain instructions executable by the processor, whereby the control unit is operative for performing at least one of the steps of the method, which is described in this disclosure. The control unit may be communicatively connected to the detection means in order to, for example, receive a signal from the detection means indicating that the drill rod is stuck. The control unit may be communicatively connected to the drill rod cutter to, for example, trigger the drill rod cutter to cut off the drill rod. The control unit may have communication means for communication with the detection means and/or the drill rod cutter, such as a receiver and a transmitter.

[0041] The drill rod cutter 20 comprises the frame 24, which, as mentioned above, is fixedly attached to the front end 113a of the feed beam 113. The frame 24 encloses the moving parts of the cutter 20 to protect them, and also serves as a chassis, carrying parts of the drill rod cutter 20. As can be seen in Fig. 4a, the frame 24 comprises a hole 24a, arranged for a guiding module 24b (see Fig. 4b), which is fixedly attach in the hole 24a of the frame 24 by screws. The guiding module 24b is arranged to surround and guide the drill rod 125 during the drilling operation. The motor 25 (visible in Fig. 3b) is fixedly arranged at the frame 24 and is arranged to drive the saw 22 by a rotational motion. The motor 25 is attached to a shaft 26, which extends in the longitudinal axis direction LA, and the motor 25 is arranged to rotate the shaft 26, wherein the shaft 26 is rotationally arranged relative the frame 24. Further, the shaft 26 comprises a disc 27, which is fixedly attached with its center to an end of the shaft 26, and the disc 27 has an extension in a plane perpendicular to the shaft 26.

[0042] The drill rod cutter 20 and thus the saw 22 is arranged perpendicular relative the drill rod 25 and thus relative the longitudinal axis direction LA. The saw 22 comprises a saw frame 31 , which is fixedly attach with a first end 31a to a cylinder part 26a surrounding the shaft 26, and which cylinder part 26a is rotatable relative the frame 24 and relative the shaft 26. A second end 31b of the saw frame 31 is arranged opposite the first end 31a and a guide slot 31c extends between the first and second ends 31a, 31 b of the saw frame 31. The saw 22 further comprises a saw blade 28 and a bow part 29, wherein the bow part 29 comprises a first end 29a and an opposite second end 29b and the saw blade 28 is attached between the first end 29a and the second end 29b of the bow part 29. The bow part 29 of the saw 22 is arranged in and guided by the guide slot 31 c of the saw frame 31 , wherein the bow part 29 may slide in the guide slot 31c, between the first end 31a and the second end 31 b of the saw frame 31. The saw 22 is by that pivotally arranged relative the frame 24, such that the saw 22 is pivotable between the resting position A and the cutting position B. This motion is controlled by an operating means 21 , which is arranged to control the cutting operation of the cutting of the drill rod 125 and which, when the drill rod cutter 20 is triggered to cut off the drill rod 125, is arranged to move the drill rod cutter 20 from its resting position A to its cutting position B. In the preferred embodiment, the operating means 21 is a hydraulic cylinder 21 , and the drill rod cutting operation is controlled by controlling the hydraulic pressure of the hydraulic cylinder 21 , such that, when the hydraulic pressure of the hydraulic cylinder 21 increases relative a pressure in which the drill rod cutter 20 is in its resting position A, the hydraulic cylinder 21 extends and by that a pressure is applied on the drill rod cutter 20, wherein the drill rod cutter 20 moves from the resting position A to the cutting position B.

[0043] As mentioned above, the motor 25 is arranged to rotate the shaft 26, and the rotational motion is intended to cause the sawing motion of the saw 22, during the cutting operation. This is possible by that the first end 29a of the bow part 29 of the saw 22 is pivotally attached to a periphery of the disc 27 via a link arm 30. When the cutting off operation is initiated, by that the detection means detect that the drill rod 125 is stuck, the motor starts and the shaft 26 starts to rotate, wherein the saw starts a sawing motion, back and forth, by that the link arm 31 is attach with one end to the periphery of the disc 27 and with its opposite end to the first end 29a of the bow part 29. Since the bow part 29 is movable, back and forth in the guide slot 31c, between the first end 31a and the second end 31b of the saw frame 31 , the sawing motion is controlled and guided as well as robustly performed, and the cutting off of the drill rod 125 may be performed. Directly after the initiation of the cutting operation, or after a period of time, or after initiation in some other way (for example by an operator), wired or remotely, the hydraulic pressure of the hydraulic cylinder 21 increases to start the cutting operation. When the pressure of hydraulic cylinder 21 increases, the cylinder 21 extends, and by that, the frame 31 (with the bow part 29 and the saw blade 28) is pushed forwards. The drill rod cutter 20 comprises a mechanical lock 23, which prevents the drill rod cutter from moving from the resting position A to the cutting position B. The mechanical lock 23 comprises a heel 23a, which is fixedly arranged on the frame 24, above the hole 24a of the frame 24, and further a lock part 23b arranged for cooperation with the heel 23a. The lock part 23b is fixedly arranged at the second end 31 b of the saw frame 31 and may be a plastic lock part 23b or of any other suitable material. The heel 23a protrudes from the frame 24 such that it serves as a stop for the lock part 23b, and the positioning of the heel 23a and the lock part 23b are of course coordinated to make the heel 23a prevent a downward motion, i.e. a motion directed towards the drill rod 125. When the pressure of hydraulic cylinder 21 increases, the cylinder 21 extends and the saw frame 31 is pushed forwards, wherein the locking function of the mechanical lock 23 ceases by that the lock part 23b slides away from the heel 23a, wherein the saw 22 is lowered in direction towards the drill rod 125. Thus, the drill rod cutter 20 moves from the resting position A to the cutting position. By controlling the pressure in the hydraulic cylinder 21 , the pressure applied to the saw 22 during the cutting operation is controlled. The hydraulic pressure to the cylinder 21 is supplied via hydraulic connectors 21a arranged on the hydraulic cylinder 21 .

[0044] Fig. 5 shows a flow chart over the inventive method for cutting the drill rod 125 at the drill arrangement 101 according to the invention. The method, which preferably is a method at least for raise caving, comprises:

- detecting 1001 , whether the drill rod 125 is stuck in the material to be drilled and cannot be retracted from the material to be drilled,

- triggering 1003, a cutting off operation, in response to detecting 1001 that the drill rod is stuck in the material to be drilled and cannot be retracted from the material to be drilled, and

- cutting off 1005, by the drill rod cutter 20, the drill rod 125.

These are the main steps, but the method may further comprise that the triggering 1003 of the drill rod cutter 20 to cut off the drill rod 125 is performed after a predetermined period of time or remotely. This means for example that the when the detection means registers a “jammed” drill rod., one option could be that for example a warning signal is triggered, wherein an operator may trigger the cutting off operation of the drill rod. Another option may be for example that the control unit may initialize an automatic cutting off operation based on that the drill rod is detected as stuck in the material to be drilled and cannot be retracted from the same. The control unit may further be arranged to inform a central control unit that the detecting means has detected that the drill rod is stuck and to await until an instruction from the central control unit to cut off the drill rod is received, before triggering cut off of the drill rod. This functions as an extra control step before the cutting off operation. The central control unit may be located remotely from the drill arrangement. The control unit and the central control unit may be communicatively connectable, for example via a wireless connection.

[0045] According to an alternative embodiment, the control unit is to wait a predetermined time period after the detection unit detected that the drill rod is stuck before triggering cut off the drill rod. This, to avoid unnecessary cutting off of the drill rod until a check might be done, which may be a visual check by the operator, by a camera or other type of check or action to be taken before the cutting off operation. According to an alternative embodiment, the control unit is arranged to inform the central control unit that the detecting means has detected that the drill rod is stuck, by transmitting information remotely via wireline or wireless communication and to receive the instruction to cut off the drill rod from the central control unit via the wireline or wireless communication.

[0046] The cutting off 1005 may further comprise:

- moving 1007 the drill rod cutter 20 from the resting position A to the cutting position B, by an operating means 21 , and then

- applying 1009 a pressure force on the drill rod cutter 20 by the operating means 21 . The operating means 21 thus controls the movement of the cutting tool (i.e. the saw) of the drill rod cutter such that it leaves its resting position and moves in direction towards the drill rod which is stuck. The operating means 21 further continues to control the motion such that a pressure is applied to the cutting tool of the drill rod cutter during the cutting off operation, to make sure there is enough force to perform the cutting off of the drill rod. Preferably, the operating means 21 is a hydraulic cylinder 21 , controlled by controlling the pressure of the cylinder during the moving 1007 and the applying 1009 steps. In this case, when the operating means 21 is a hydraulic cylinder 21 , the method further may comprise that:

- the cutting off 1005 comprises increasing 1013 a pressure in the hydraulic cylinder 21 , for moving 1007 the drill rod cutter 20 from the resting position A to the cutting position B and for applying 1009 the pressure force on the drill rod cutter 20. Preferably also a step of controlling 1015 the pressure in the hydraulic cylinder 21 during the cutting off operation, is used to have the full control of the complete cutting off operation. Preferably, the pressure in the hydraulic cylinder 21 then is lowered after the cutting off of the drill rod is complete, wherein the cutting tool (i.e. the saw) of the drill rod cutter may be moved back to its resting position.

[0047] When the drill rod cutter 20 comprises a saw 22 as the cutting tool, the method further comprises that:

- the cutting off 1005 comprises starting 1006 a motor 25 arranged to drive a back and forth motion of the saw 22, and

- the applying 1009 of a pressure force on the drill rod cutter 20 by the operating means 21 comprises applying a pressure on the saw 22 by the operating means 21 . The motor 25 is started at some state after the cutting off operation is triggered, preferably the motor 25 is started after the moving 1007 of the drill rod cutter 20 from its resting position A, when the movement proceeds towards the drill rod 125 which is to be cut off. After the drill rod 125 is cut off, the method may comprise a step of stopping the motor 25.

[0048] Although the description above contains a plurality of specificities, these should not be construed as limiting the scope of the concept described herein but as merely providing illustrations of some exemplifying embodiments of the described concept. It will be appreciated that the scope of the presently described concept fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the presently described concept is accordingly not to be limited. Reference to an element in the singular is not intended to mean "one and only one" unless explicitly so stated, but rather "one or more." All structural and functional equivalents to the elements of the abovedescribed embodiments that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed hereby. Moreover, it is not necessary for an apparatus or method to address each and every problem sought to be solved by the presently described concept, for it to be encompassed hereby. In the figures, a broken line generally signifies that the feature within the broken line is optional.

Claims

1. Drill arrangement (101) comprising:

- a drill rod (125) which extends along a longitudinal axis (LA),

- drill driving means (106) arranged to drive the drill rod (125) in a direction of the longitudinal axis (LA), and into a material to be drilled,

- detection means arranged to detect whether the drill rod (125) is stuck in the material to be drilled and cannot be retracted from the material to be drilled,

- a drill rod cutter (20), arranged for cutting the drill rod (125), and

- a control unit arranged to trigger the drill rod cutter (20) to cut off the drill rod (125) in response to the detection means detecting that the drill rod is stuck in the material to be drilled and cannot be retracted from the material to be drilled.

2. Drill arrangement (101) according to claim 1 , wherein the control unit is arranged to inform a central control unit that the detecting means has detected that the drill rod (125) is stuck and to await until an instruction from the central control unit to cut off the drill rod (125) is received, before triggering cut off of the drill rod (125).

3. Drill arrangement (101) according to claim 1 or 2, wherein control unit is to wait a predetermined time period after the detection unit detected that the drill rod is stuck before triggering cut off the drill rod (125).

4. Drill arrangement (101) according to any claims 2-3, wherein the control unit is arranged to inform the central control unit that the detecting means has detected that the drill rod (125) is stuck by transmitting information remotely via wireline or wireless communication and to receive the instruction to cut off the drill rod (125) from the central control unit via the wireline or wireless communication.

5. Drill arrangement (101) according to any of the preceding claims, wherein the drill rod cutter (20) is arrangeable in a resting position (A) and a cutting position (B), wherein when the drill rod cutter (20) is triggered to cut off the drill rod (125), the drill rod cutter (20) is moved from the resting position (A) to the cutting position (B).

6. Drill arrangement (101) according to any of the preceding claims, wherein the drill rod cutter (20) comprises a saw (22) arranged substantially perpendicular to the drill rod (125), when it is to cut the drill rod (125).

7. Drill arrangement (101) according to claim 6, wherein the saw (22) of the drill rod cutter (20) is pivotally arranged at the drill arrangement (101) such that the saw (22) is pivotable between the resting position (A) and the cutting position (B).

8. Drill arrangement (101) according to any of claims 5-7, wherein the drill rod cutter (20) comprises a mechanical lock (23) with a locking function which prevents the drill rod cutter from moving from the resting position (A) to the cutting position (B).

9. Drill arrangement (101) according to any of the preceding claims, wherein the drill rod cutter (20) further comprises an operating means (21 ) arranged to control a cutting operation of the cutting of the drill rod (125) and which, when the drill rod cutter (20) is triggered to cut off the drill rod (125), is arranged to move the drill rod cutter (20) from its resting position (A) to its cutting position (B).

10. Drill arrangement (101) according to claim 9, wherein the operating means (21) is a hydraulic cylinder (21 ), and the drill rod cutting operation is controlled by controlling the hydraulic pressure of the hydraulic cylinder (21), wherein, when the hydraulic pressure of the hydraulic cylinder (21) increases relative a pressure in which the drill rod cutter (20) is in its resting position (A), the hydraulic cylinder (21) extends and by that a pressure is applied on the drill rod cutter (20), wherein the drill rod cutter (20) moves from the resting position (A) to the cutting position (B).

11 . Drill arrangement (101) according to claim 10 when dependent on claim 8, wherein when the hydraulic cylinder (21) extends, the locking function of the mechanical lock (23) ceases and the drill rod cutter (20) moves from its resting position (A) towards its cutting position (B).

12. Drill arrangement (101) according to any of claims 6-11 , wherein the drill rod cutter (20) further comprising:

- a frame (24) arranged for fixed connection of the drill rod cutter (20) to the drill arrangement (101),

- a motor (25), fixedly arranged at the frame (24), wherein the motor (25) is attached to a shaft (26) extending in the longitudinal axis direction (LA), wherein the motor (25) is arranged to rotate the shaft (26), and the shaft (26) comprises a disc (27), which is fixedly attached with its center to an end of the shaft (26), perpendicular to the shaft (26), wherein the saw (22) is pivotally arranged at the frame (24) and comprises a saw blade (28) and a bow part (29), wherein the bow part (29) comprises a first end (29a) and an opposite second end (29b), wherein the saw blade (28) is attached between the first end (29a) and the second end (29b) of the bow part (29), and wherein the first end (29a) of the bow part (29) is pivotally attached to a periphery of the disc (27) via a link arm (30).

13. Method for cutting a drill rod (125) at a drill arrangement (101 ) according to any of claims 1-12, which drill arrangement (101) is positioned so that it is out of reach/inaccessible for personnel, the method comprising:

- detecting (1001) whether the drill rod (125) is stuck in the material to be drilled and cannot be retracted from the material to be drilled,

- triggering (1003) a cutting off operation, in response to detecting (1001) that the drill rod is stuck in the material to be drilled and cannot be retracted from the material to be drilled,

- cutting off (1005), by the drill rod cutter (20), the drill rod (125).

14. Method according to claim 13, wherein the triggering (1003) of the drill rod cutter (20) to cut off the drill rod (125) is performed after a predetermined period of time.

15. Method according to any of claims 13-14, wherein the triggering (1003) of the drill rod cutter (20) to cut off the drill rod (125) is performed remotely.

16. Method according to any of claims 13-15, wherein the cutting off (1005) comprises:

- moving (1007) the drill rod cutter (20) from a resting position (A) to a cutting position (B), by an operating means (21),

- applying (1009) a pressure force on the drill rod cutter (20) by the operating means (21).

17. Method according to claim 16, wherein when the operating means (21) is a hydraulic cylinder (21 ), the method further comprising:

- the cutting off (1005) comprises increasing (1013) a pressure in the hydraulic cylinder (21), for moving (1017) the drill rod cutter (20) from the resting position (A) to the cutting position (B) and for the applying (1009) the pressure force on the drill rod cutter (20).

18. Method according to claim 17, wherein the method further comprising:

- controlling (1015) the pressure in the hydraulic cylinder (21) during the cutting off operation.

19. Method according to claim any of claims 16-18, wherein when the drill rod cutter (20) comprises a saw (22), the method further comprising:

- the cutting off (1005) comprises starting (1006) a motor (25) arranged to drive a back and forth motion of the saw (22), and

- the applying (1009) of a pressure force on the drill rod cutter (20) by the operating means (21) comprises applying a pressure on the saw (22) by the operating means (21).

20. Method according to any of the claims 13-19, wherein the method is a method for raise caving.