Method and system for removing a drill rod from a drill string

Abstract

A method for removing a drill rod from a drill string of a drilling equipment further comprising a rock drill, a rod handling system including first mechanical clamping means and second mechanical clamping means. The drill string comprises at least a first threaded drill rod and a second threaded drill rod. The method comprises: a) when the first threaded drill rod is connected to the rock drill by a first threaded joint, rattling (201) the drill string to loosen a second threaded joint of the drill string, the second threaded joint joining the first drill rod and the second drill rod, wherein the second threaded joint comprises a second thread of the second drill rod mating with a first thread of the first drill rod; b) tightening (202) the first threaded joint; c) while a rotation pressure of the rock drill is below a first threshold pressure unthreading (203) a first portion of the first thread from the second thread; d) determining (204) that a rotation pressure of the rock drill applied to the drill string is above a second threshold pressure; e) unthreading (208) the first thread from the second thread completely; f) unthreading (209) the rock drill; and g) removing (210) the first drill rod.

Description

[0001] METHOD AND SYSTEM FOR REMOVING A DRILL ROD FROM A DRILL STRING

[0002] TECHNICAL FIELD OF THE INVENTION

[0003] The embodiments herein relate to mining, and, more specifically, to a method for automated removal of a drill rod from a drill string, for example for extraction of a drill string from a hole. The invention also relates to a computer program implementing the method according to the invention, as well as a drill rig.

[0004] BACKGROUND OF THE INVENTION

[0005] In mines and other work sites, rock drills mounted on rigs are used to drill holes in the bedrock. Percussive rock drilling is a common method to drill in rock. Examples of common percussive rock drilling methods are top hammer drilling, Down-the-Hole (DTH) and COPROD.

[0006] During percussive rock drilling, rock is crushed by a drill bit striking the rock at a high frequency, whereby buttons arranged on the drill bit crush the rock. The drill is rotated in order for the buttons to hit new rock surfaces with each impact. Since drilling is often performed in deep holes, the drill bit is often arranged on a drill rod, which is in turn arranged on an adapter mounted in a drilling machine, such as a rock drill. The adapter, the drill rod and the drill bit together form an assembly called a drill string. To ensure contact between the drill bit and the rock and that the adapter is in a preferred position in the drilling machine during drilling, a feed force, directed towards the rock, is applied to the drilling machine, e.g. by a hydraulic piston. Hence, the feed force acts on the drill string and on the rock through the drilling machine.

[0007] In a percussive drilling machine, a percussive element, such as a percussive piston, impacts the adapter, whereby the impulse is distributed along the drill string, down the hole and finally into the rock via the drill bit. One or more drill rods may be joined to extend the drill string. For example, a plurality of drill rods may be joined together by means of joints when drilling longer holes in order to lengthen the drill string to allow that a hole of a desired length may be drilled. The drill rods are in general threaded, and further drill rods are therefore added by being threaded together with the current drill string as the drilling of the hole progress. Following a concluded drilling operation, i.e. drilling of a particular hole, the drill string is retrieved from the drilled hole, rod by rod, where the drill string is pulled backwards and the drill rods are decoupled from each other. However, the joints of the drill rods may become such firmly tightened during drilling that a high loosening torque may be required to loosen the joints and thereby allow the drill rods to be separated from each other and removed from the drill string. The joints may even become so firmly tightened that the joints cannot be loosened only with the assistance of a rotation unit.

[0008] There exist various solutions for accomplishing the loosening of the joints, where e.g. a joint loosening mechanism may be utilised. The joint loosening mechanism applies a joint loosening torque by means of a lever action acting on the drill string. Solutions of this kind, however, may impose excessive wear on the drill string components.

[0009] Document WO2022203564 discloses a method for detecting a loosened joint of a drill string. The joints are broken by applying a loosening torque using a dedicated breakout tool.

[0010] In another example, as part of a prior art solution the operator, after the drilling of the hole has ended, strikes the drill rods with the percussion device while they are not under feed force, whereby a suitable number of impacts have loosened the threads. The operator does this by experience and usually stops the striking when hearing a certain type of noise or vibration from the drill rod. Thus, it is difficult for the operator to detect the loosening of the threads and it does not always succeed the first time. A problem is that unnecessary striking after the threads are already open wears and may even damage the drill rods. Further, the fact that the operator has to do this manually prevents automatization.

[0011] Document WO2011138511 discloses a method for opening threaded joints of drilling equipment by striking the drilling equipment with the percussion device of a rock drilling rig, the method comprising measuring vibration originating from the drill rod during striking and analysing the measured vibration according to a predefined principle for the purpose of determining whether the threaded joints have opened.

[0012] Existing manually controlled solutions for retrieving the drill rods have a high failure rate and thus are unreliable.

[0013] SUMMARY OF THE INVENTION

[0014] An object of the invention is to obviate some of the problems related to retrieving a drill string of the prior art. It is a further object of the invention to provide a method and system that may be utilised in retrieving the drill string in a more efficient way compared to prior art. An alternative object is to achieve an alternative solution compared to prior art.

[0015] According to a first aspect, the object is achieved by a method for removing a drill rod from a drill string of a drilling equipment for drilling a drill hole. In the end, the method may be for extracting a drill string of a drilling equipment from the hole. The drilling equipment further comprises a rock drill, a rod handling system including first mechanical clamping means, such as a mechanical gripper, and second mechanical clamping means. The drill string comprises at least a first threaded drill rod and a second threaded drill rod.

[0016] The method comprises, when the first drill rod is connected to the rock drill by a first threaded joint of the drill string, rattling the drill string to loosen a second threaded joint of the drill string. The second threaded joint joins the first drill rod and the second drill rod. The second threaded joint comprises a second thread of the second drill rod mating with a first thread of the first drill rod.

[0017] The method further comprises tightening the first threaded joint by gripping the first drill rod with the first mechanical clamping means and rotating the rock drill in a joint tightening direction.

[0018] The method further comprises, while a rotation pressure of the rock drill is below a first threshold pressure, unthreading a first portion of the first thread of the first drill rod from the second thread of the second drill rod by rotating the rock drill in a joint loosening direction while gripping the second drill rod with the second mechanical clamping means and moving the rock drill away from the second threaded joint.

[0019] The method further comprises gripping the first drill rod by the first mechanical clamping means and rotating the rock drill in the joint loosening direction while moving the rock drill away from the first drill rod and determining, based on a pressure value of a rotation pressure sensor of the drilling equipment, that a rotation pressure of the rock drill applied to the drill string is above a second threshold pressure.

[0020] The method further comprises unthreading the first thread of the first drill rod from the second thread of the second drill rod completely by rotating the rock drill in the joint loosening direction while moving the rock drill away from the second threaded joint.

[0021] The method further comprises unthreading the rock drill from the first drill rod by gripping the first drill rod by the first mechanical clamping means and rotating the rock drill in the joint loosening direction while moving the rock drill away from the first drill rod.

[0022] The method further comprises removing the first drill rod from the drill string. According to a second aspect, the object is achieved by a drilling equipment for drilling a drill hole. The drilling equipment further comprises a rock drill, a rod handling system including first mechanical clamping means, such as a mechanical gripper, and second mechanical clamping means. The drill string comprises at least a first threaded drill rod and a second threaded drill rod.

[0023] The drilling equipment is configured to remove a drill rod from the drill string by being configured to perform the method according to the first aspect. That is, the drilling equipment is configured to remove a drill rod from the drill string by being configured to, when the first drill rod is connected to the rock drill by a first threaded joint of the drill string, rattle the drill string to loosen a second threaded joint of the drill string. The second threaded joint joins the first drill rod and the second drill rod. The second threaded joint comprises a second thread of the second drill rod mating with a first thread of the first drill rod.

[0024] The drilling equipment is further configured to tighten the first threaded joint by being configured to grip the first drill rod with the first mechanical clamping means and rotate the rock drill in a joint tightening direction.

[0025] The drilling equipment is further configured to, while a rotation pressure of the rock drill is below a first threshold pressure, unthread a first portion of the first thread of the first drill rod from the second thread of the second drill rod by being configured to rotate the rock drill in a joint loosening direction while gripping the second drill rod with the second mechanical clamping means and move the rock drill away from the second threaded joint.

[0026] The drilling equipment is further configured to grip the first drill rod by the first mechanical clamping means and rotating the rock drill in the joint loosening direction while moving the rock drill away from the first drill rod and determine, based on a pressure value of a rotation pressure sensor of the drilling equipment, that a rotation pressure of the rock drill applied to the drill string is above a second threshold pressure.

[0027] The drilling equipment is further configured to unthread the first thread of the first drill rod from the second thread of the second drill rod completely by being configured to rotate the rock drill in the joint loosening direction while moving the rock drill away from the second threaded joint.

[0028] The drilling equipment is further configured to unthread the rock drill from the first drill rod by being configured to grip the first drill rod by the first mechanical clamping means and rotate the rock drill in the joint loosening direction while moving the rock drill away from the first drill rod. The drilling equipment is further configured to remove the first drill rod from the drill string.

[0029] According to a third aspect, the object is achieved by a rock drilling rig comprising a drilling equipment according to the second aspect.

[0030] According to a further aspect, the object is achieved by a computer program comprising instructions, which when the program is executed by a computer, causes the computer to perform the method actions according to the first aspect above.

[0031] According to a further aspect, the object is achieved by a computer-readable medium comprising instructions which, when executed by a computer, cause the computer to carry out the method according to the first aspect above.

[0032] Since the drill string is rattled, multiple joints, such as all the joints, of the drill string may be loosened with reduced wear of the joints and the drill string. Since loose joints are determined based on that the pressure value of the rotation pressure sensor of the drilling equipment during the unthreading of the first portion is below the threshold pressure for unthreading of the first threaded joint, reduced wear of the drill string is achieved as the rattling is not continued after the joint has been determined to be loose by the pressure sensor.

[0033] In embodiments herein the drill rods may be extracted from the hole by checking that a correct thread is loose. The entire drill string is picked up completely automatically.

[0034] Thus, embodiments herein enable automatic drill string extraction with reduced wear.

[0035] BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In the figures, features that appear in some embodiments are indicated by dashed lines.

[0037] The various aspects of embodiments disclosed herein, including particular features and advantages thereof, will be readily understood from the following detailed description and the accompanying drawings, in which:

[0038] Figure 1a illustrates a simplified rock drilling rig in which embodiments of the invention may be utilised, Figure 1b also illustrates a simplified rock drilling rig in which embodiments of the invention may be utilised,

[0039] Figure 1c illustrates a zoom-in of a threaded joint and mechanical clamping means,

[0040] Figure 2 is a flowchart and illustrates a method according to some embodiments of the invention,

[0041] Figure 3 is a flowchart and illustrates some further methods according to some further embodiments of the invention,

[0042] Figure 4 is a flowchart and illustrates some further methods according to some further embodiments of the invention,

[0043] Figure 5 is a flowchart and illustrates some further methods according to some further embodiments of the invention,

[0044] Figure 6 is a flowchart and illustrates some further methods according to some further embodiments of the invention,

[0045] Figure 7 is a flowchart and illustrates some further methods according to some further embodiments of the invention,

[0046] Figure 8 is a flowchart and illustrates some further methods according to some further embodiments of the invention,

[0047] Figure 9 is a flowchart and illustrates some further methods according to some further embodiments of the invention.

[0048] DETAILED DESCRIPTION

[0049] The present invention is described in more detail below, with references to the appended drawings showing examples of embodiments. The invention should not be viewed as limited to the described examples of embodiments, instead it is defined by the appended patent claims. Like numbers refer to like elements throughout the description.

[0050] Embodiments of the present invention will be exemplified in the following in view of a particular kind of drill rig, where drilling is carried out through the use of a percussion device in the form of a top hammer. The invention is, however, applicable also for other kinds of drill rigs, such as down-the-hole (DTH)Zin-the-hole (ITH) hammer. The drill rig may also be of any other kind, with a percussive element.

[0051] For example, the drilling machine as well as rotation unit may be arranged on the opposite end of the drill string in relation to the drill bit, such as on a carriage of a feed beam, and the drilling machine and rotation unit may also form an integrated unit providing both percussion and rotation. The invention is also applicable for drill rigs comprising other kinds of drilling machines than hydraulically driven drilling machines, such as drilling machines operated by electrical or pneumatical means.

[0052] Fig. 1a illustrates a rock drilling rig 100 according to an exemplary embodiment of the present invention for which an inventive method of extracting a drill string of a drilling equipment from a hole 10 will be described. The rock drilling rig 100 is in the process of drilling the hole, where the drilling currently has reached a depth x.

[0053] The rock drilling rig 100 according to the present example constitutes a surface drill rig, although it is to be understood that the drill rig may also be of a type being primarily intended e.g. for underground drilling, or a drill rig for any other use. The rock drilling rig 100 comprises a carrier 101. The carrier may carry a boom not illustrated in Fig. 1a, in a conventional manner. Furthermore, a feed beam 103 may be attached to the boom. The feed beam 103 carries a carriage 104, which also may be referred to as a cradle, which is slidably arranged along the feed beam 103 to allow the carriage 104 to run along the feed beam 103. The feed beam 103 may be arranged such that it extends in a vertical direction with respect to the ground and thus the carriage 104 may run along the vertical direction.

[0054] The carriage 104, in turn, carries a rock drill 105. The rock drill 105 comprises a percussion device, e.g., in the form of a top hammer.

[0055] As the name implies, the top hammer (percussion device) works at a top end of a drilling tool, such as a drill string 107, where an impact piston (not shown) of the top hammer strikes the drill tool such as a drill rod of the drill string 107 in order to transfer shock wave energy to a drill bit 106 of the drill tool and further into the rock for breaking thereof. Top hammers are useful, inter alia, in that they offer high drilling speed and efficiency, are suitable for hard rock drilling, require minimal maintenance and downtime, and are versatile.

[0056] The rock drill 105 may further comprise a rotation unit. Rotation of the rotation unit translates into rotation of the drill string 107. The rotation unit may provide rotation in both directions of rotation. The rotation is indicated by 117. The rotation unit provides rotation of the drill string 107 during drilling to ensure that drill bit inserts of the drill bit 106 are indexed between strokes of the percussion piston to avoid the drill bit inserts from repeatedly striking the rock in the same manner.

[0057] A feed force may also be provided to the drill string 107 to thereby press the drill bit against the rock face being drilled. The feed force may be provided in various known ways. For example, a feed cylinder may be mounted inside but not enclosed within the feed beam 103. The feed cylinder pushes / pulls on a pulley block. The pulley block may be connected to the carriage 104 with steel wires.

[0058] The drill string 107 may consist of a single drill rod being threaded together with rock drill 105, e.g., with the rotation unit and the percussion device. The drill string 107, however, oftentimes does not consist of a drill string in one piece, but, instead, of a number of drill rods. When drilling has progressed a distance corresponding to a drill rod length, a new drill rod is threaded together with the one or more drill rods that already has been threaded together to form the drill string, whereby drilling can progress for another drill rod length before a new drill rod is threaded together with existing drill rods. Drill rods of the disclosed kind may be extended essentially to any desired length as drilling progress. This is illustrated by drill rods 107-1 to 107-3, which are joined together by threaded joints 135, 136. It is to be noted that the invention is applicable to drill strings having any number of joints. The first threaded drill rod 107-1 is connected to the rock drill 105 by a first threaded joint 134 of the drill string 107. The drill bit 106 may be threaded together with drill rod 107-3 by means of a threaded joint. The first drill rod 107-1 may comprise the first threaded joint 134 and the second drill rod 107-2 may comprise the second threaded joint 135.

[0059] The rock drilling rig 100 may further comprise a rod handling system 130 for moving the drill rods to and from a drilling position, also referred to as a drilling center, and a magazine 130a in which the drill rods may be stored when not in use. The rod handling system 130 may comprise arms 130b for moving the drill rods between the different positions. The arms 130b of the rod handling system may for example move in a horizontal direction.

[0060] The rod handling system 130 may comprise first mechanical clamping means 131 , 132. The first mechanical clamping means 131 , 132 may also be referred to as grippers of the rod handling system 130. The first mechanical clamping means 131 , 132 may releasably hold the first drill rod 107-1. The first mechanical clamping means 131 , 132 may clamp a drill rod with a hard grip which hinders the drill rod from rotation due to friction. The first mechanical clamping means 131 , 132 may further guide the drill rod with a loose grip. When the first mechanical clamping means 131 , 132 are open a drill rod may be released in the magazine 130a.

[0061] The rock drilling rig 100 may further comprise one or more drill rod supports, such as an upper drill rod support 141 and a lower drill rod support 142. The lower drill rod support 142 may be arranged below the upper drill rod support 141 in the drilling direction when the rock drilling rig 100 is arranged for drilling.

[0062] The upper drill rod support 141 may have hydraulic jaws inside to grip joints of the drill string 107.

[0063] The lower drill rod support 142 may also have hydraulic jaws inside to guide the drill rods while drilling.

[0064] As an example, the rotation unit is powered by pressurized hydraulic fluid being supplied to the percussion device by one or more hydraulic pumps arranged on the carrier 101 and suitable hosing. The carrier 101 may also comprise a hydraulic fluid tank from which hydraulic fluid is taken and returned to using the hydraulic circuit powering the rotation unit. There may be further hydraulic pumps being used to provide pressurised hydraulic fluid in one or more additional hydraulic circuits, such as e.g. a damping circuit.

[0065] Furthermore, the top hammer may be driven by compressed air and for this reason compressed air is led to the hammer where the compressed air is supplied from a tank through a suitable coupling, and a hose or other suitable means as is known per se and therefore not illustrated herein. The compressed air is generated by a compressor, which may charge the tank from which the compressed air is supplied to the drill string.

[0066] The hydraulic pumps, compressor and other power consumers such as e.g. further compressors and further hydraulic pumps are driven by a power source, e.g. in the form of a combustion engine such as a diesel engine or any other suitable power source, such as e.g. an electric motor, or combination of power sources. The rock drilling rig 100 may also comprise a pressure sensor being used to measure the pressure of the hydraulic circuit powering the rotation unit. It is to be understood that various other pressure sensors, and also other types are sensors are utilised in connection with drill rigs of the disclosed example. Such sensors are in general not illustrated for reasons of simplicity.

[0067] The rock drilling rig 100 further comprises a rig control system comprising at least one control unit 120. The control unit 120 is configured to control various of the functions of the rock drilling rig 100, such as controlling the drilling process. In case the rock drilling rig 100 is manually operated, the control unit 120 may receive control signals from the operator, e.g. being present in an operator cabin 114 through operator controllable means such as joysticks and other means requesting various actions to be taken, and where the control signals, such as operator inflicted joystick deflections and / or manoeuvring of other means, may be translated by the control system to suitable control commands. The control unit 120 may, for example, be configured to request motions to be carried out by various actuators such as cylinders / motors / pumps etc., e.g. for manoeuvring boom, feed beam 103 and controlling the percussion device and rotation unit, and various other functions. The described control, as well as other functions, may alternatively be partly or fully autonomously controlled by the control unit 120.

[0068] The control unit is configured to control the rock drill 105 and the rod handling system 130 to perform the method according to any of the embodiments herein.

[0069] Drill rigs of the disclosed kind may also comprise more than one control unit, e.g. a plurality of control units, where each control unit, respectively, may be arranged to be responsible for monitoring and carrying out various functions of the rock drilling rig 100. For reasons of simplicity, however, it will be assumed in the following that the various functions are controlled by the control unit 120. Such control systems may further utilise any suitable kind of data bus to allow communication between various units of the rock drilling rig 100. In case the rock drilling rig 100 is manoeuvred by an operator various data may be displayed e.g. on one or more displays in the operator cabin 114.

[0070] When the drilling of a hole is finished, the drill rod is retracted from the drilled hole where, during the retraction, the components forming the drill string are loosened from each other as the drill string is being pulled out. Extraction of the drill string of the drilling equipment from the hole according to embodiments of the invention is partly or fully performed by a control unit of the drill rig, such as control unit 120 of fig. 1a.

[0071] With regard to extraction of the drill string, the rock drilling rig 100 of Fig. 1a may further comprise distance monitoring means, such as a length sensor 160. The length sensor 160 may be mounted on the side of the feed beam. It may sense a specific metal part on the carriage 104 and when the carriage 104 changes position the length sensor 160 outputs different values which may be used to calculate a current vertical position of the carriage 104 with respect to a reference point.

[0072] Some positions that will be used below are:

[0073] M2: a thread of the rock drill 105 has been completely inserted into the first drill rod 107-1.

[0074] M3: the lowest point of the thread of the rock drill 105 is just above the first threaded joint 134 of the drill string 107.

[0075] M4: the second joint 135 is in the upper drill rod support 141 as illustrated in Fig. 1a. M5: the lower edge of the first drill rod 107-1 (i.e., edge of first thread of first drill rod 107-1) is arranged at a height such that it is possible to move it to the magazine, as illustrated in Fig. 1 b.

[0076] According to embodiments of the invention the rods of the drill string 107 are extracted from the hole 10 by checking that a correct thread is loose, i.e., that at least the second joint 135 joining the first drill rod 107-1 and the second drill rod 107-2 is loose. If the wrong thread is loose, such as the first joint 134 joining the rock drill 105 and the first drill rod 107-1, or no thread is loose, the sequence of actions may either restart or the error may be solved by striking the drill string 107 in the drill rod support, such as the upper drill rod support 141. The entire drill string 107 is picked up completely automatically.

[0077] Fig. 2 is a flowchart and illustrates some exemplary methods according to embodiments of the invention by means of which it is possible to extract the drill string 107 of the drilling equipment from the hole 10. The methods are for removing the drill rod 107-1 from the drill string 107 of the drilling equipment. As mentioned above the drilling equipment is for drilling the drill hole 10. The drilling equipment further comprises the rock drill 105 and the rod handling system 130 including first mechanical clamping means 131 , 132. The first mechanical clamping means 131 , 132 are used to hold the first drill rod 107- 1. When the first mechanical clamping means 131, 132 holds the first drill rod 107-1 in a hard grip then the first drill rod 107-1 will not rotate together with the rock drill 105 when the rock drill is attempting to rotate. Instead, the rock drill 105 may thread in or out of the first drill rod 107-1 when the first mechanical clamping means 131, 132 hold the first drill rod 107-1 in a hard grip. The drilling equipment further comprises second mechanical clamping means 141-1 , 142-1. The second mechanical clamping means 141-1 , 142-1 may be part of the upper and lower drill rod supports 141, 142.

[0078] The drill string 107 comprises at least the first threaded drill rod 107-1 and the second threaded drill rod 107-2.

[0079] The methods comprise one or more of the following actions, which actions may be taken in any suitable order.

[0080] Action 201

[0081] In embodiments disclosed herein removing the drill rod 107-1 from the drill string

[0082] 107 comprises rattling the drill string 107. More specifically, when the first threaded drill rod 107-1 is connected to the rock drill 105 by the first threaded joint 134 of the drill string 107, the rock drilling rig 100 rattles the drill string 107 to loosen a second threaded joint 135 of the drill string 107. A zoom-in of a cross-section of the second threaded joint 135 is illustrated in Fig. 1c. The second threaded joint 135 joins the first drill rod 107-1 and the second drill rod 107-2. The second threaded joint 135 comprises a second thread 135-2 of the second drill rod 107-2 mating with a first thread 135-1 of the first drill rod 107-1. The second thread 135-2 of the second drill rod 107-2 may be a female thread and the first thread 135-1 of the first drill rod 107-1 may be a male thread as illustrated in Fig. 1c.

[0083] In some embodiments rattling the drill string 107 comprises striking the drill string 107 against a surfacelOa of the drill hole 10. In some other embodiments rattling the drill string 107 comprises striking the drill string 107 against one of the drill rod supports 141, 142, such as the upper drill rod support 141. More specifically, the drill string 107 may be stroked against the second mechanical clamping means 141-1 of the upper drill rod support 141. To rattle the drill string 107 the rock drilling rig 100 may open the upper drill rod support 141 and the lower drill rod support 142 and activate percussion by the percussive element.

[0084] In some embodiments disclosed herein rattling the drill string 107 further comprises feeding the drill string 107 forward or rotating the drill string 107 in the joint loosening direction or both.

[0085] Action 202

[0086] After the rattling the rock drilling rig 100 tightens the first threaded joint 134 by gripping the first drill rod 107-1 with the first mechanical clamping means 131, 132 and rotating the rock drill 105 in a joint tightening direction. The first mechanical clamping means 131, 132 may grip the first drill rod 107-1 such that it is fastened to the first mechanical clamping means 131 , 132 during the tightening and thus cannot rotate along with the rock drill 105. Thereby the first threaded joint 134 is tightened. In this way the method makes sure that the first joint 134 is not accidentally unthreaded as well during the unthreading of the second joint 135.

[0087] The rotation unit may be of various different designs and operate according to various different technologies. A non-limiting example will now be presented.

[0088] A rotation motor may be selectively controlled to rotate in both directions of rotation in dependence of present requirements. For example, during drilling the rotation motor is controlled to provide a rotation in a tightening direction, i.e. acts to tighten the threads of the various joints of the drill string 107 through the rotation of the drill string 107. According to embodiments of the invention, on the other hand, the rotation unit is utilized in the loosening of the joints, in which case rotation of the rotation unit 109 in the direction opposite to the rotation direction during drilling is utilized. The direction of rotation of the rotation motor may be controlled by means of a directional control valve which may be set to, according to the present example, three different states, wherein a first state turns off the rotation whereas two further states provides for the two different directions of rotation. According to the present example, one state represents the setting of the rotation motor in the loosening direction.

[0089] Furthermore, the rotation motor may be controlled by a hydraulic pump by means of which the rotation unit may be controlled in regard of rotation pressure as well as speed of rotation.

[0090] Action 203

[0091] An attempt at unthreading a first portion 135-11 of the first thread 135-1 may be used for checking whether or not the second joint 135 is loose enough for unthreading the first thread 135-1 without unthreading the rock drill 105 from the first joint 134. During the attempt of unthreading the first portion 135-11 a rotation pressure may be monitored periodically during a specified time period. If it is detected that the rotation pressure is above the threshold pressure then it is determined that the second joint is not loose enough. Then additional actions may be taken to loosen the second joint 135 while making sure that the first joint 134 is not loosened. If on the other hand it is not detected that the rotation pressure is above the threshold pressure then it is determined that the second joint 135 is loose enough.

[0092] Thus, while a rotation pressure of the rock drill 105 is below a first threshold pressure the method continues with unthreading the first portion 135-11 of the first thread 135-1 of the first drill rod 107-1 from the second thread 135-2 of the second drill rod 107-2 by rotating the rock drill 105 in a joint loosening direction while gripping the second drill rod 107-1 with the second mechanical clamping means 141-1 , 142-1 and moving the rock drill 105 away from the second threaded joint 135 which is indicated by the arrow in Figure 1c. Specifically, the upper drill rod support 141 may be used to fix the second joint 135 during the unthreading of the first thread 135-1 from the second thread 135-2. The rotation pressure may be based on a pressure value of a rotation pressure sensor of the drilling equipment.

[0093] In some embodiments herein the first portion 135-11 of the first thread 135-1 is preferably between 40-60 % of a total length of the first thread 135-1 , more preferably 45 to 55 % of the total length of the first thread 135-1 , even more preferably close to 50 % of the total length of the first thread 135-1. If the first thread 135-1 is unthreaded too much there is a risk of dropping the drill string.

[0094] Action 204

[0095] If the first portion 135-11 of the first thread 135-1 was successfully unthreaded without detection of the rotation pressure surpassing the threshold pressure, then the method continues with checking that the first joint is still not loose. This is performed by gripping the first drill rod (107-1) by the first mechanical clamping means (131 , 132) and rotating the rock drill (105) in the joint loosening direction while moving the rock drill (105) away from the first drill rod (107-1) and determining, based on the pressure value of the rotation pressure sensor of the drilling equipment, that a rotation pressure of the rock drill 105 applied to the drill string 107 during the unthreading of the first portion 135-11 of the first thread 135-1 is above a second threshold pressure.

[0096] Action 205

[0097] If in the method actions described above it is detected that the second joint 135 is not loose enough or that the first joint 134 is too loose then the method may continue with tightening the first joint 134.

[0098] For example, if it is determined that the rotation pressure of the rock drill 105 applied to the drill string 107 during the unthreading of the first portion 135-11 of the first thread 135-1 of the first drill rod 107-1 from the second thread 135-2 of the second drill rod 107-2 is above the first threshold pressure then the method may comprise tightening the first threaded joint 134 by gripping the first drill rod 107-1 with the first mechanical clamping means 131, 132 and rotating the rock drill 105 in a joint tightening direction.

[0099] A hard grip of the first mechanical clamping means 131 , 132 may be used when tightening the first joint 134.

[0100] The method may further comprise, after unthreading the first portion 135-11 of the first thread 135-1 of the first drill rod 107-1 and then tightening the first threaded joint 134: performing actions 201-204 above and action 208-210 below.

[0101] Action 206

[0102] The method may further comprise, after unthreading the first portion 135-11 of the first thread 135-1 of the first drill rod 107-1 and then tightening the first threaded joint 134, to determine whether or not the first drill rod 107-1 is a last drilled drill rod. That is, whether the first drill rod 107-1 was the uppermost drill rod used to produce the hole 10.

[0103] For example, the method may comprise determining that the first drill rod 107-1 is not a last drilled drill rod and performing actions 201-204 and 208-210 after determining that the first drill rod 107-1 is not a last drilled drill rod. Then rattling the drill string 107 after determining that the first drill rod 107-1 is not a last drilled drill rod may be performed by striking the drill string 107 against a drill rod support.

[0104] Action 207

[0105] In some embodiments disclosed herein the method further comprises, after unthreading the first portion 135-11 of the first thread 135-1 of the first drill rod 107-1 and then tightening the first threaded joint 134, to determine whether or not the drill string 107 has made contact with the bottom 10a of the drill hole 10.

[0106] For example, the method may further comprise, after unthreading the first portion 135-11 of the first thread 135-1 of the first drill rod 107-1 and then tightening the first threaded joint 134, to determine that the drill string 107 has made contact with a bottom of the drill hole. Then the method may further comprise performing actions 201 to 204 and 208-210 after determining that the drill string 107 has made contact with the bottom of the drill hole. Then rattling the drill string 107 after determining that the drill string 107 has made contact with the bottom of the drill hole may be performed by striking the drill string 107 against a surface 10a of the drill hole 10.

[0107] The determining that the drill string 107 has made contact with the bottom of the drill hole may be based on a damper pressure.

[0108] Action 208

[0109] Once it has been determined that the second joint 135 is loose enough and the first joint 134 is tight enough then the method continues with unthreading the first thread 135-1 of the first drill rod 107-1 from the second thread 135-2 of the second drill rod 107-2 completely by rotating the rock drill 105 in the joint loosening direction while moving the rock drill 105 away from the second threaded joint 135.

[0110] Action 209

[0111] The method further comprises unthreading the rock drill 105 from the first drill rod 107-1 by gripping the first drill rod 107-1 by the first mechanical clamping means 131, 132 and rotating the rock drill 105 in the joint loosening direction while moving the rock drill

[0112] 105 away from the first drill rod 107-1. A hard grip may be used for action 209.

[0113] Action 210

[0114] Then the drill rig 100 removes the first drill rod 107-1 from the drill string 107.

[0115] Action 211

[0116] The method may then continue with threading in the second drill rod 107-2. To do so the rock drill 105 is fed forward and attached to the second drill rod 107-2. If there are more than two drill rods, then the method may be used again for the second drill rod 107- 2.

[0117] Fig. 3 is a flowchart and also illustrates some exemplary methods according to embodiments of the invention by means of which it is possible to extract the drill string 107 of the drilling equipment from the hole 10. The flowchart of Fig. 3 describes the method to extract the drill string 107 in a complementary way to the flowchart of Fig. 2. The methods comprise one or more of the following actions, which actions may be taken in any suitable order.

[0118] Action 301

[0119] The drill rig 100 rattles the drill string 107 to loosen all the joints 134, 135, 136 of the drill string 107. Action 301 is related to action 201.

[0120] Action 302

[0121] The drill rig 100 tightens the first joint 134. Action 302 is related to action 202.

[0122] Action 303

[0123] The drill rig 100 unthreads a first distance of the first thread 135-1. Action 303 is related to action 203.

[0124] Action 304

[0125] During the unthreading the drill rig 100 checks whether or not the second joint 135 is loose by measuring the rotation pressure. Action 304 is related to action 203.

[0126] Actions 305a and 305b The drill rig 100 checks whether or not the first joint 134 is loose by measuring the rotation pressure. For example, in action 305a the rock drilling rig 100 measures the rotation pressure while attempting to unthread the first joint 134 from the rock drill 105. Then, in action 305b the rock drilling rig 100 determines whether or not the first joint 134 is loose or not. Actions 305a and 305b are related to action 204.

[0127] Action 306

[0128] If the first joint 134 is not loose then the drill rig 100 continues to unthread a second portion 135-12 (i.e., a second distance) of the first thread 135-1 until the first thread 135- 1 is completely unthreaded. The first drill rod 107 is then put in the magazine 330a. Action 306 is related to actions 208-210.

[0129] Action 307

[0130] The drill rig 100 may then thread in the next drill rod, i.e., the second drill rod 107-2. Action 307 is related to action 211 .

[0131] Action 308

[0132] The drill rig 100 may then determine whether or not the second drill rod 107-2 is the first drilled rod. If the second drill rod 107-2 is the first drilled rod then the method ends. If the second drill rod 107-2 is not the first drilled rod then the method may continue with action 302 again.

[0133] Action 309

[0134] If in action 304 it is determined that the second joint 135 is loose, or in action 305b it is determined that the first joint 134 is loose then the drill rig 100 may continue to tighten the first joint 134 again. Action 309 is related to action 205.

[0135] Action 310

[0136] The drill rig 100 may then check whether or not the first drill rod 107-1 is the last drilled rod. Action 309 is related to action 206.

[0137] Action 311

[0138] If the first drill rod 107-1 is the last drilled rod then the rock drilling rig 100 searches for the bottom 10a of the hole 10 in order to rattle the drill string 107 against the bottom 10a of the hole 10. Action 310 is related to actions 207 and 201. Action 312

[0139] If the first drill rod 107-1 is not the last drilled rod then the rock drilling rig 100 rattles the drill string 107 against the drill rod supports 141 , 142, for example against the upper drill rod support 141. Action 311 is related to action 201.

[0140] Fig. 4 is a flowchart and illustrates details of action 301 , i . e. , the rattling of the drill string 107, of Fig. 3.

[0141] The methods comprise one or more of the following actions, which actions may be taken in any suitable order.

[0142] Action 401

[0143] To rattle the drill string 107 the rock drilling rig 100 may open the upper drill rod support 141 and the lower drill rod support 142.

[0144] Action 402

[0145] Then percussion may be activated for a certain time, indicated by delay 1 in Fig.4.

[0146] Action 403

[0147] Then feed forward may be activated for a certain time, indicated by delay 2 in Fig.4.

[0148] Action 404

[0149] Then feed forward may be de-activated.

[0150] Action 405

[0151] After a certain time, indicated by delay 3 in Fig.4. backwards rotation may be activated for a certain time, indicated by delay 4 in Fig.4.

[0152] Action 406

[0153] Then backwards rotation may be de-activated.

[0154] Action 407

[0155] After a certain time, indicated by delay 5 in Fig.4. feed forward may be activated again for a certain time, indicated by delay 6 in Fig.4. Action 408

[0156] Then feed forward may be de-activated.

[0157] Action 409

[0158] After a certain time, indicated by delay 7 in Fig.4. backwards rotation may be activated for a certain time, indicated by delay 8 in Fig.4.

[0159] Action 410

[0160] Then backwards rotation may be de-activated.

[0161] Action 411

[0162] After a certain time, indicated by delay 9 in Fig.4 percussion may be de-activated. The method may then continue to action 501 of Flowchart 2 in Fig. 5.

[0163] Fig. 5 is a flowchart and illustrates details of some of the actions of Fig. 3. The methods comprise one or more of the following actions, which actions may be taken in any suitable order.

[0164] Actions 501- 511 below illustrate details of action 302, and / or action 309, i.e., the tightening of the first joint 134, of Fig. 3.

[0165] Action 501

[0166] To tighten the first joint 134 the rock drilling rig 100 may activate feed backwards, rotation in the joint tightening direction and compressed air. This is performed until reference point M4 is reached. The length sensor monitors the vertical position and detects when position M4 is reached.

[0167] Action 502

[0168] When position M4 has been reached the rock drilling rig 100 may de-activate feed backwards, rotation in the joint tightening direction and compressed air.

[0169] Action 503

[0170] The arms 130b of the rod handling system 130 may then move to a drill center position.

[0171] Action 504 In the drill center position the arms 130b may be closed.

[0172] Action 505

[0173] The hard grip of the first mechanical clamping means 131 , 132 of the rod handling system 130 may be activated.

[0174] Action 506

[0175] The first drill rod support 141 may be opened.

[0176] Action 507

[0177] The rock drilling rig 100 may activate thread in. That is, the first joint is threaded onto the rock drill 105, e.g., by rotating the rock drill 105 in the joint tightening direction while feeding the rock drill 105 forward.

[0178] Action 508

[0179] A timer may be started.

[0180] Action 509

[0181] While the timer is running the rock drilling rig 100 checks whether or not the rotation pressure is above a tightening threshold. If the rotation pressure is determined to be below the tightening threshold then the timer is restarted, i.e. , the method returns to action 508.

[0182] Action 510

[0183] If the rotation pressure is determined to be above the tightening threshold then it is checked whether the timer has expired.

[0184] If the timer hasn’t expired then the rock drilling rig 100 continues to check whether or not the rotation pressure is above the tightening threshold, i.e., the method returns to action 509.

[0185] Action 511

[0186] If the timer has expired then the rock drilling rig 100 de-activates the threading of the first joint 134. Actions 512-517 below illustrate details of action 303, i.e., of unthreading the first portion 135-11 of the first thread 135-1.

[0187] Action 512

[0188] The first mechanical clamping means 131 , 132 of the rod handling system 130 may be opened.

[0189] Action 513

[0190] The rock drilling rig 100 may activate feed backwards until position M4 is reached.

[0191] Action 514

[0192] It is checked whether position M4 has been reached.

[0193] Action 515

[0194] When position M4 has been reached the rock drilling rig 100 may de-activate feed backwards.

[0195] Action 516

[0196] The rock drilling rig 100 may further close the upper drill rod support 141.

[0197] Action 517

[0198] The loose grip of the first mechanical clamping means 131 , 132 of the rod handling system 130 may be activated. There may be a delay time after this action.

[0199] Action 518

[0200] The rock drilling rig 100 may activate unthread. There may be a time for attempting to unthread. A timer may be set for the unthreading.

[0201] Action 519

[0202] The rotation pressure may be measured.

[0203] Action 520

[0204] If the rotation pressure is above a threshold pressure for unthreading it assumed that the second joint 135 is not loose and unthreading is de-activated. The method may then continue to action 801 of Flowchart 5 in Fig. 8. Action 521

[0205] While the rotation pressure is below the threshold pressure the rock drilling rig 100 checks whether or not the first portion 135-11 of the first thread 135-1 has been unthreaded. This may be achieved by checking whether output from the length sensor 160 matches with a position that corresponds to position M4 minus the length of the first portion 135-11 of the first thread 135-1. For example, if the first portion is half the length of the first thread 135-1 then it may be checked whether M4-half the length of the first portion 135-11 of the first thread 135-1 has been reached, as illustrated in Fig. 5. If the first portion 135-11 of the first thread 135-1 has not been unthreaded at the measurement time the method may return to action 519.

[0206] Action 522

[0207] When the first portion 135-11 of the first thread 135-1 has been unthreaded unthreading may be de-activated. After a wait time to apply the hard grip, the method may then continue to action 601 of Flowchart 3 in Fig. 6.

[0208] Fig. 6 is a flowchart and illustrates details of some of the actions of Fig. 3. The methods comprise one or more of the following actions, which actions may be taken in any suitable order.

[0209] Actions 601- 607 below illustrate details of actions 305a and 305b, i.e. , the checking of the first joint 134, of Fig. 3.

[0210] Action 601

[0211] The hard grip of the first mechanical clamping means 131 , 132 of the rod handling system 130 may be activated.

[0212] Action 602

[0213] Rotation in the joint loosening direction may be activated.

[0214] Action 603

[0215] A timer for checking whether the first joint 134 is loose may be started.

[0216] Action 604

[0217] It is checked whether or not the timer has expired. Action 605

[0218] If the timer expires the first joint 134 is determined to be loose and the rotation is deactivated and the method may continue to action 501 of Flowchart 2 in Fig. 5, i.e., to tighten the first joint 134.

[0219] Action 606

[0220] It is checked whether or not the rotation pressure is above a threshold pressure for determining that the first joint 134 is loose or tight.

[0221] Action 607

[0222] If the rotation pressure is determined to be below the threshold pressure in action 606 then the first joint 134 is determined to be tight enough to continue with the unthreading of the second joint 135 and the rotation is de-activated.

[0223] Actions 608-611 below illustrate details of action 306, i.e., of unthreading the second portion 135-12 of the first thread 135-1, of Fig. 3.

[0224] Action 608

[0225] The first mechanical clamping means 131 , 132 may be opened.

[0226] Action 609

[0227] The loose grip of the first mechanical clamping means 131 , 132 may be activated. There may be a delay time between the activation of the loose grip and the next action.

[0228] Action 610

[0229] Unthreading may be activated.

[0230] Action 611

[0231] The rock drilling rig 100 checks whether or not the second portion 135-11 of the first thread 135-1 has been unthreaded and thus whether or not the complete first thread 135- 1 has been unthreaded. This may be achieved by checking whether output from the length sensor 160 matches with a position that corresponds to position M4 minus the length of the first thread 135-1 , as illustrated in Fig. 6. If the first thread 135-1 has not been unthreaded at the measurement time the method may return to action 610. Actions 612-620 below illustrate further details of action 306, i.e., of unthreading the rock drill 105 from the first joint 134 and putting the first drill rod 107-1 in the magazine 130a, of Fig. 3.

[0232] Action 612

[0233] Rotation may be de-activated, that is turned off.

[0234] Action 613

[0235] The rock drilling rig 100 checks whether or not reference position M5 has been reached.

[0236] Action 614

[0237] Feed backwards is de-activated.

[0238] Action 615

[0239] Hard grip of first clamping means 131, 132 is activated.

[0240] Action 616

[0241] Unthreading is de-activated.

[0242] Action 617

[0243] The rock drilling rig 100 checks whether or not reference position M5 minus the length of the thread of the first joint 134 has been reached. All threads may have the same length. If not the method may return to action 616.

[0244] Action 618

[0245] If reference position M5 minus the length of the thread of the first joint 134 has been reached then unthreading may be de-activated.

[0246] Action 619

[0247] Flush air may be activated. A duration for the flush air may be set.

[0248] Action 620

[0249] Flush air may be de-activated. Then the method may continue to Flowchart 4 of Figure 7 which will be described below. Fig. 7 is a flowchart and illustrates details of some of the actions of Fig. 3. The methods comprise one or more of the following actions, which actions may be taken in any suitable order.

[0250] Actions 701- 710 below illustrate details of action 307, i.e., the threading of the second drill rod 137-2, of Fig. 3.

[0251] Action 701

[0252] The arms 130b of the rod handling system 130 may move to the magazine position.

[0253] Action 702

[0254] The first clamping means 131 , 132 may open.

[0255] Action 703

[0256] The first drill rod 107-1 may be put in the magazine 130a. The magazine 130a may comprise empty compartments referenced by an index for storage of the drill rods.

[0257] Action 704

[0258] Feed forward may be activated.

[0259] Action 705

[0260] It is checked whether position M3 is reached.

[0261] Action 706

[0262] When position M3 is reached feed forward is de-activated.

[0263] Action 707

[0264] Threading of the second drill rod 107-2 is activated.

[0265] Action 708

[0266] The position of the length sensor 160 is monitored and the threading in continues until position M2 minus half the length of the thread has been reached.

[0267] Action 709 When position M2 minus half the length of the thread has been reached it is checked whether or not the rotation pressure is above a threshold pressure for threading in. If the pressure is above the threshold pressure then the method continues to action 710 below.

[0268] Action 710

[0269] Thread in is de-activated.

[0270] Actions 711- 715 below illustrate details of action 308, i.e., checking whether or not the second drill rod 137-2 is the first drilled rod, of Fig. 3.

[0271] Action 711

[0272] Both the upper and lower rod supports 141 , 142 may be opened.

[0273] Action 712

[0274] It is checked whether the second drill rod 107-2 is the first drilled steel. If not the method continues to action 501 of Flowchart 2 in Figure 5.

[0275] Action 713

[0276] If the second drill rod 107-2 is the first drilled steel then feed backwards is activated.

[0277] Action 714

[0278] The vertical position of the carriage 104 is monitored against position M4 offset, which is an end of hole position, a position where the drill bit should be when the hole is complete.

[0279] Action 715

[0280] When the M4 offset position is reached feed backwards is de-activated. The method may then end.

[0281] Fig. 8 is a flowchart and illustrates details of some of the actions of Fig. 3. The methods comprise one or more of the following actions, which actions may be taken in any suitable order.

[0282] Actions 801- 810 below illustrate details of action 309, i.e., the tightening of the first joint 134, of Fig. 3. Action 801

[0283] The hard grip of the first mechanical clamping means 131 , 132 of the rod handling system 130 may be activated.

[0284] Action 802

[0285] The rock drilling rig 100 may further close the upper drill rod support 141. The lower drill rod support 142 may be closed.

[0286] Action 803

[0287] Thread in is activated.

[0288] Action 804

[0289] A timer for tightening the first joint 134 may be started.

[0290] Action 805

[0291] It is checked whether or not the rotation pressure is above a threshold pressure for determining that the first joint 134 is tight. If the rotation pressure is below the threshold pressure then the method may return to action 804.

[0292] Action 806

[0293] It is checked whether the timer has expired.

[0294] Action 807

[0295] If the timer expires thread in is de-activated.

[0296] Action 808

[0297] The first mechanical clamping means 131 , 132 are opened.

[0298] Action 809

[0299] The arms 130b of the rod handling system 130 may move to the magazine position.

[0300] Action 810

[0301] Thread in is activated for a certain time.

[0302] Action 811 Thread in is de-activated

[0303] Action 812

[0304] The drill rig 100 may then check whether or not the first drill rod 107-1 is the last drilled rod.

[0305] If the first drill rod 107-1 is the last drilled rod then the method may continue to action 901 of Flowchart 6 in Fig. 9 below, in which case the rock drilling rig 100 searches for the bottom 10a of the hole 10 in order to rattle the drill string 107 against the bottom 10a of the hole 10.

[0306] If the first drill rod 107-1 is not the last drilled rod then the method may continue to action 906 of Flowchart 6 in Fig. 9 below, in which case the rock drilling rig 100 rattles the drill string 107 against the drill rod supports 141 , 142, for example against the upper drill rod support 141.

[0307] Fig. 9 is a flowchart and illustrates details of some of the actions of Fig. 3. The methods comprise one or more of the following actions, which actions may be taken in any suitable order.

[0308] Actions 901- 905 below illustrate details of action 311 , i.e., the searching of the bottom 10a of the hole 10, of Fig. 3.

[0309] Action 901

[0310] Both the upper and lower rod supports 141 , 142 are opened.

[0311] Action 902

[0312] The damper is activated. An idle pressure is stored.

[0313] Action 903

[0314] The damper pressure is monitored and it is compared to a threshold pressure which equals the idle pressure of the damper plus an offset. The offset may be around 10 bars, such as 9-11 bars, or more preferably 9,9-10,1 bars.

[0315] Action 904

[0316] While the damper pressure is below the idle pressure of the damper plus the offset then flush air, feed forward, percussion and rotation is activated. Action 905

[0317] When the damper pressure is above the idle pressure of the damper plus the offset then flush air, feed forward, percussion and rotation is de-activated. The method may then continue to action 401 of Flowchart 1 in Figure 4.

[0318] Actions 906- 9 below illustrate details of action 312, i.e., the rattling of the drill string 107 against the drill rod supports 141 , 142, for example against the upper drill rod support 141., of Fig. 3.

[0319] Action 906

[0320] Upper rod support 141 is opened.

[0321] Action 907

[0322] Feed forward is activated.

[0323] Action 908

[0324] It is checked whether position M4 is reached. Feed forward is continued while position M4 is not reached.

[0325] Action 909

[0326] When position M4 is reached feed backwards is de-activated.

[0327] Action 910

[0328] The upper drill rod support 141 is closed.

[0329] Action 911a, 911b, 911c

[0330] Percussion, feed forward and rotation is activated in parallel and sustained for certain time periods that may be set.

[0331] Action 912a, 912b, 912c

[0332] Percussion, feed forward and rotation is then de-activated.

[0333] Action 913

[0334] Feed forward is activated again for a second time period. Action 914

[0335] Feed forward is de-activated.

[0336] Action 915

[0337] The arms 130b of the rod handling system 130 may then move to a drill center position. The method may then continue to action 501 in Fig. 5.

[0338] The present invention may be utilised for essentially any kind of drill rig where a rotation pressure may be measured. The invention is applicable for underground drill rigs as well drill rigs operating above ground.

[0339] Furthermore, the invention has been exemplified with regard to a hydraulic drilling machine and hydraulic rotation unit. It is, however, also contemplated according to the invention that other technologies may be utilised, such as e.g. an electric rotation unit comprising an electrical machine. When an electric rotation unit is utilised, e.g. an electrical current can be monitored instead of a pressure according to the above, and a desired speed of rotation of the electrical machine can be set in a straightforward manner using suitable control electronics as is known per se.

[0340] When using the word "comprise" or “comprising” it shall be interpreted as nonlimiting, i.e. , meaning "consist at least of".

[0341] The embodiments herein are not limited to the above described preferred embodiments. Various alternatives, modifications and equivalents may be used.

Claims

CLAIMS1. A method for removing a drill rod (107-1) from a drill string (107) of a drilling equipment for drilling a drill hole (10), wherein the drilling equipment further comprises a rock drill (105), a rod handling system (130) including first mechanical clamping means (131 , 132), and second mechanical clamping means (141-1 , 142-1) and wherein the drill string (107) comprises at least a first threaded drill rod (107-1) and a second threaded drill rod (107-2), wherein the method comprises: a) when the first threaded drill rod (107-1) is connected to the rock drill (105) by a first threaded joint (134) of the drill string (107), rattling (201) the drill string (107) to loosen a second threaded joint (135) of the drill string (107), the second threaded joint (135) joining the first drill rod (107-1) and the second drill rod (107-2), wherein the second threaded joint (135) comprises a second thread (135-2) of the second drill rod (107-2) mating with a first thread (135-1) of the first drill rod (107-1); b) tightening (202) the first threaded joint (134) by gripping the first drill rod (107-1) with the first mechanical clamping means (131 , 132) and rotating the rock drill (105) in a joint tightening direction; c) while a rotation pressure of the rock drill (105) is below a first threshold pressure unthreading (203) a first portion (135-11) of the first thread (135-1) of the first drill rod (107-1) from the second thread (135-2) of the second drill rod (107-2) by rotating the rock drill (105) in a joint loosening direction while gripping the second drill rod (107-1) with the second mechanical clamping means (141-1 , 142-1) and moving the rock drill (105) away from the second threaded joint (135); d) gripping the first drill rod (107-1) by the first mechanical clamping means (131 , 132) and rotating the rock drill (105) in the joint loosening direction while moving the rock drill (105) away from the first drill rod (107-1) and determining (204) that a rotation pressure of the rock drill (105) applied to the drill string (107) is above a second threshold pressure; e) unthreading (208) the first thread (135-1) of the first drill rod (107-1) from the second thread (135-2) of the second drill rod (107-2) completely by rotating the rock drill (105) in the joint loosening direction while moving the rock drill (105) away from the second threaded joint (135); f) unthreading (209) the rock drill (105) from the first drill rod (107-1) by gripping the first drill rod (107-1) by the first mechanical clamping means (131 , 132) and rotating the rock drill (105) in the joint loosening direction while moving the rock drill (105) away from the first drill rod (107-1); andg) removing (210) the first drill rod (107-1) from the drill string (107).

2. The method according to claim 1, wherein rattling the drill string (107) comprises striking the drill string (107) against a surface (10a) of the drill hole (10) or against the second mechanical clamping means (141-1, 142-1).

3. The method according to claim 2, wherein rattling the drill string (107) further comprises feeding the drill string (107) forward and rotating the drill string (107) in the joint loosening direction.

4. The method according to any of the claims 1-3, further comprising: determining () that the rotation pressure of the rock drill (105) applied to the drill string (107) during the unthreading of the first portion (135-11) of the first thread (135-1) of the first drill rod (107-1) from the second thread (135-2) of the second drill rod (107-2) is above the first threshold pressure; and tightening () the first threaded joint (134) by gripping the first drill rod (107-1) with the first mechanical clamping means (131 , 132) and rotating the rock drill (105) in a joint tightening direction.

5. The method according to claim 4, further comprising, after unthreading the first portion (135-11) of the first thread (135-1) of the first drill rod (107-1) and then tightening the first threaded joint (134): performing actions a) to g) of claim 1.

6. The method according to claim 5, further comprising, after unthreading the first portion (135-11) of the first thread (135-1) of the first drill rod (107-1) and then tightening the first threaded joint (134): determining that the drill string (107) has made contact with a bottom (10a) of the drill hole (10) and performing actions a) to g) of claim 1 after determining that the drill string (107) has made contact with the bottom (10a) of the drill hole (10), wherein rattling the drill string (107) after determining that the drill string (107) has made contact with the bottom (10a) of the drill hole is (10) performed by striking the drill string (107) against a surface (10a) of the drill hole (10).

7. The method according to claim 6, wherein determining that the drill string (107) has made contact with the bottom (10a) of the drill hole (10) is based on a damper pressure.

8. The method according to claim 6, further comprising, after unthreading the first portion (135-11) of the first thread (135-1) of the first drill rod (107-1) and then tightening the first threaded joint (134): determining that the first drill rod (107-1) is not a last drilled drill rod; and performing actions a) to g) of claim 1 after determining that the first drill rod (107-1) is not a last drilled drill rod, wherein rattling the drill string (107) after determining that the first drill rod (107-1) is not a last drilled drill rod is performed by striking the drill string (107) against the second mechanical clamping means (141-1 , 142-1).

9. The method according to any of the claims 1-8, wherein the first portion (135-11) of the first thread (135-1) is between 40-60 % of a total length of the first thread (135-1), more specifically 45 to 55 % of the total length of the first thread (135-1).

10. Computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method according to any one of the claims 1-9.

11. Computer-readable medium comprising instructions which, when executed by a computer, cause the computer to carry out the method according to any one of the claims 1-9.

12. A drilling equipment for drilling a drill hole, the drilling equipment comprising a rock drill (105), a rod handling system (130) including first mechanical clamping means (131 , 132), and second mechanical clamping means (141 , 142), and a drill string (107) which comprises at least a first threaded drill rod (107-1) and a second threaded drill rod (107-2), wherein the drilling equipment is configured to remove a drill rod from the drill string (107) by: a) when the first threaded drill rod (107-1) is connected to the rock drill (105) by a first threaded joint (134) of the drill string (107), rattling the drill string (107) to loosen a second threaded joint (135) of the drill string (107), the second threaded joint (135) joining the first drill rod (107-1) and the second drill rod (107-2), wherein the second threaded joint (135) comprises a second thread of the second drill rod (107-2) mating with a first thread (135-1) of the first drill rod (107-1);b) tightening the first threaded joint (134) by gripping the first drill rod (107-1) with the first mechanical clamping means (131 , 132) and rotating the rock drill (105) in a joint tightening direction; c) while a rotation pressure of the rock drill (105) is below a first threshold pressure unthreading a first portion (135-11) () of the first thread (135-1) of the first drill rod (107-1) from the second thread (135-2) of the second drill rod (107-2) by rotating the rock drill (105) in a joint loosening direction while gripping the second drill rod (107-1) with the second mechanical clamping means (141-1, 142-1) and moving the rock drill (105) away from the second threaded joint (135); d) gripping the first drill rod (107-1) by the first mechanical clamping means (131, 132) and rotating the rock drill (105) in the joint loosening direction while moving the rock drill (105) away from the first drill rod (107-1) and determining that a rotation pressure of the rock drill (105) applied to the first drill string (107) is above a second threshold pressure107; e) unthreading the first thread (135-1) of the first drill rod (107-1) from the second thread (135-2) of the second drill rod (107-2) completely by rotating the rock drill (105) in the joint loosening direction while moving the rock drill (105) away from the second threaded joint (135); f) unthreading the rock drill (105) from the first drill rod (107-1) by gripping the first drill rod (107-1) by the first mechanical clamping means (131, 132) and rotating the rock drill (105) in the joint loosening direction while moving the rock drill (105) away from the first drill rod (107-1); and g) removing the first drill rod (107-1) from the drill string (107).

13. The drilling equipment according to claim 12, further comprising a drill rod support (141, 142) comprising the second mechanical clamping means (141-1, 142-1).

14. The drilling equipment according to claim 12 or 13, wherein the first drill rod (107-1) comprises the first threaded joint (134) and the second drill rod (107-2) comprises the second threaded joint (135).

15. The drilling equipment according to any of the claims 12-14, further comprising a control unit (120) configured to control the rock drill (105) and the rod handling system (130) to perform the method according to any one of claims 1-9.

16. Rock drilling rig (100) characterised in that it comprises a drilling equipment according to any one of claims 12-15.

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