A method for cracking a rock

Abstract

The invention involves a method for cracking a rock or a part of a bedrock, comprising - drilling a hole (201) into the rock (202) such that the hole extends into the rock or the bedrock part from a mouth (203) at a surface of the rock or the bedrock part, - providing a rock cracking cartridge (1) comprising a rock cracking powder charge (102), the cartridge further comprising an ignition arrangement (104), wherein the ignition arrangement is adapted to ignite the powder charge (102) when the ignition arrangement is subjected to a force directed towards the powder charge, - moving the cartridge (1) towards a bottom of the hole (201) with the ignition arrangement (104) at the front, and subjecting, by contact with the bottom (204) of the hole, the ignition arrangement to a force directed towards the powder charge (102) whereby the powder charge is ignited, - wherein the method comprises, while moving the cartridge (1) towards the bottom of the hole (201), moving blocking material (110) behind the powder charge (102) to block the hole (201) between the powder charge and the mouth (203) of the hole, wherein the rock cracking cartridge (1) comprises the blocking material (110).

Description

[0001] A METHOD FOR CRACKING A ROCK

[0002] TECHNICAL FIELD

[0003] The invention relates to a method for cracking a rock or a part of a bedrock, and to a rock cracking arrangement.

[0004] BACKGROUND

[0005] In fields, such as mining, quarrying and earthmoving, where rocks and bedrock are present, rocks or bedrock parts are cracked with rock cracking cartridges in order to disintegrate the rock material, to facilitate handling, e.g. removal, of the rock material.

[0006] US2002050223 describes placing a cartridge assembly at the bottom of a hole drilled into a rock. The hole is filled with an incompressible fluid medium such as water. A pressure pulse is generated at a mouth of the hole, by firing of a blank cartridge, and the pressure pulse is propagated into the hole via the fluid medium. One end of the cartridge assembly is exposed to the pressure pulse to cause a force amplifying initiating device to be actuated to initiate a primer to fire the cartridge assembly.

[0007] US7942481B2 describes a method of breaking rock which includes the steps of drilling a hole in the rock using a drill rod; leaving the drill rod in the hole; using water flow to direct a propellant charge into the hole through a passage in the drill rod; and at a leading end of the drill rod, firing the propellant charge with, at least, the drill rod and water in the hole and passage providing a stemming function. Using water both as a propellant for the propellant charge and for providing a stemming function, requires that the machine used is adapted to produce a powerful water flow, and the solution therefore appears cumbersome and difficult to handle.

[0008] There is a desire to provide a rock cracking method which is simpler to execute than known methods.SUMMARY

[0009] It is an object of the invention to provide a rock cracking method which is easy to execute.

[0010] This object is achieved with a method for cracking a rock or a part of a bedrock, comprising drilling a hole into the rock or the bedrock part such that the hole extends into the rock or the bedrock part from a mouth at a surface of the rock or the bedrock part, providing a rock cracking cartridge comprising a rock cracking powder charge, the cartridge further comprising an ignition arrangement, wherein the ignition arrangement is adapted to ignite the powder charge when the ignition arrangement is subjected to a force directed towards the powder charge,

[0011] moving the cartridge towards a bottom of the hole with the ignition arrangement at the front, and subjecting, by contact with the bottom of the hole, the ignition arrangement to a force directed towards the powder charge whereby the powder charge is ignited,

[0012] - wherein the method comprises, while moving the cartridge towards the bottom of the hole, moving blocking material behind the powder charge to block the hole between the powder charge and the mouth of the hole, wherein the rock cracking cartridge comprises the blocking material.

[0013] The rock or the bedrock part to be cracked may be a loose rock, e.g. a block of stone, or a fixed rock, e.g. a part of a bedrock. The bottom of the hole may be formed by the rock or the bedrock part, or by a plug inserted into or formed in the hole after the drilling of it. The hole may be drilled such that it extends from the mouth and terminates inside the rock or the bedrock part. The rock cracking powder charge may comprise nitrocellulose powder. The ignition arrangement may be an ignition mechanism. The rock cracking cartridge may be elongated. The ignition arrangement may be located at an outer surface of the cartridge. The ignition arrangement may be located at one end of the cartridge.

[0014] It is understood that the powder charge is preferably behind the ignition arrangement when the cartridge is moved towards the bottom of the hole. Moving the cartridge towards the bottom of the hole may comprise moving the cartridge into the hole. The cartridge may be moved towards the bottom of the hole so that the ignition arrangement is by contact with the bottom of the hole subjected to a force towards the powder charge whereby the powder chargeis ignited. Thereby, the contact of the ignition arrangement with the bottom of the hole may be a collision of the ignition arrangement with the bottom of the hole. Thereby, by means of the collision, the ignition arrangement is subjected to a force directed towards the powder charge whereby the powder charge is ignited.

[0015] By moving the cartridge towards the bottom of the hole, and subjecting, by contact with the bottom of the hole, the ignition arrangement to a force directed towards the powder charge whereby the powder charge is ignited, the powder charge is caused to detonate. Hereby, the rock or the bedrock part will crack. Embodiments of the method may basically comprise only the drilling step and the cartridge moving step. Thus, the method provides a way to crack a rock or a bedrock part which is easy and quick to exercise.

[0016] The step of drilling the hole may be done with a drill which is mounted on a vehicle. The vehicle and the drill may be remote controlled. The step of moving the cartridge towards the bottom of the hole may be done by means of compressed air. Alternatively, the cartridge may be moved by spring action, or by an explosive charge. In further alternatives, the cartridge is pushed relatively slowly into the hole, and pushed against the end of the hole so that the ignition arrangement is activated. For this the cartridge may be mounted to an end of an arm which is pushed into the hole. A device for providing the movement of the cartridge, whether by compressed air, by hydraulic means, mechanically, e.g. by spring action, or any other suitable way, may be mounted on a vehicle. The vehicle and the movement providing device may be remote controlled. Thereby the method may be performed in a safe way for staff involved in it.

[0017] By moving, while moving the cartridge towards the bottom of the hole, blocking material behind the powder charge to block the hole between the powder charge and the mouth of the hole, the blocking material may be inserted along with the powder charge to block the hole in the direction towards the mouth. Thereby, energy from the powder charge ignition escaping through the mouth of the hole, may be avoided. The blocking material may be of any suitable kind. For example it may comprise stone chips such as crushed stone or gravel, clay, lead bullets, plastic plugs, and / or tungsten shot. Stone chips may provide a particularly good mechanical interlocking effect. Preferably the density of the blocking material is at least 1100 kg / mA3, more preferably at least 1300 kg / mA3, even more preferably at least 1500 kg / mA3.By the rock cracking cartridge comprising the blocking material, the cartridge integrates the functions of providing energy for the rock cracking and blocking energy toward the mouth of the hole. This simplifies the use of the cartridge, as separate means for blocking the energy are not needed. In addition, the invention provides flexibility regarding the propulsion of the cartridge, so that a simple means for this propulsion can be used.

[0018] In some embodiments, subjecting the ignition arrangement to the force directed towards the powder charge is done by means of a pushing device pushing the cartridge towards the bottom of the hole. Thereby, as exemplified below, where the step of drilling the hole is done by means of a drill, the drill may be used, subsequently to the drilling, as the pushing device. Thereby, the drill may be withdrawn from the hole once the drilling step is finished, and subsequently the cartridge may be placed between the drill and the bottom of the hole.

[0019] Thereby, the drill may be used to push the cartridge towards the bottom of the hole so that the powder charge is ignited. Thereby, the alignment of the drill with the hole may be taken advantage of for the pushing step. Nevertheless, in some embodiments, the pushing device could be a part, e.g. an arm, which is separate from the drill.

[0020] In some embodiments, e.g. where the hole is angled downwards from the mouth of the hole, moving the cartridge towards the bottom of the hole may be done by allowing the cartridge to slide by its own weight to the bottom of the hole. Thereupon the pushing device may be used to push, or bias, the cartridge towards the bottom of the hole so that the powder charge is ignited. To avoid ignition upon the end of the moving step, as exemplified below, the cartridge may be provided with a protection cap which covers the ignition arrangement. The protection cap may be adapted to break when the cartridge is biased by the pushing device towards the bottom of the hole, if the biasing force is larger than a threshold force for breaking the protection cap.

[0021] Preferably, the cartridge comprises a material distribution device located on a side of the powder charge which is opposite to the side of the powder charge on which the ignition arrangement is located, which material distribution device is tapered so that upon the ignition arrangement being subjected to the force directed towards the powder charge, the tapered shape of the material distribution device forces the blocking material outwards, laterally to the longitudinal direction of the hole. As described below, the tapered shaped material distribution device may be cone shaped. In some embodiments, the material distributiondevice is tapered in a direction away from the powder charge. Thereby, the material distribution device may be located between the blocking material and the powder charge. Thereby, the tapered shaped material distribution device may serve to spread the blocking material sideways upon the contact, or impact, of the cartridge with the bottom of the hole. The material distribution device is preferably solid, and may be made e.g. in hard plastic or metal. In some embodiments, the material distribution device is tapered in a direction towards the powder charge. Thereby, the blocking material may be located between the material distribution device and the powder charge. Thereby, if the ignition arrangement is subjected to the force directed towards the powder charge by means of a pushing device pushing the cartridge towards the bottom of the hole, the blocking material may be biased by the ignition of the powder charge towards the pushing device. Thereby, the material distribution device forces the blocking material outwards, laterally to the longitudinal direction of the hole.

[0022] If the method is used to crack a block of stone, the hole is preferably drilled such that it extends at least 50% through the block of stone. Preferably, the hole extends no more than 80% through the block of stone, preferably no more than 75% through the block of stone. The hole may be drilled such that it extends no more than 80% through the block of stone, preferably no more than 75% through the block of stone. Thereby, a beneficial location for the release of the energy from the powder charge ignition is provided.

[0023] Reaching the object of the invention is facilitated by a rock cracking arrangement comprising a rock cracking cartridge comprising a rock cracking powder charge, the cartridge further comprising an ignition arrangement at a surface of the cartridge, wherein the ignition arrangement is adapted to ignite the powder charge when the ignition arrangement is subjected to a force directed towards the powder charge. The rock cracking arrangement comprises a material distribution device intended to be located, when the rock cracking arrangement is used, on a side of the powder charge which is opposite to the side of the powder charge on which the ignition arrangement is located, which material distribution device is tapered.

[0024] Preferably, the rock cracking arrangement further comprises blocking material which is intended to be located, when the rock cracking arrangement is used, on a side of the powder charge which is opposite to the side of the powder charge on which the ignition arrangement is located. The ignition arrangement may thus be located on a first side of the powder charge,and the blocking material and the material distribution device may be located on a second side of the powder charge. Thereby, the second side may be opposite the first side.

[0025] The material distribution device may be tapered in a direction away from the powder charge. Thereby, the material distribution device may be located between the powder charge and blocking material. However, as suggested, in some embodiments, the material distribution device is tapered in a direction towards the powder charge. Thereby, the blocking material may be located between the material distribution device and the powder charge. As mentioned the rock cracking cartridge may be elongated. Thereby, the ignition arrangement may be located at one end of the cartridge.

[0026] Where, in embodiments of the method according to the invention, the blocking material is moved towards the bottom of the hole, behind the powder charge, the tapered shape of the material distribution device forces the blocking material outwards, laterally to the longitudinal direction of the hole. Thereby, when used in embodiments of the method according to the invention, the blocking function of the blocking material is augmented. The material distribution device may be at least partly conical. The tapered shape serves to spread the blocking material sideways.

[0027] In some embodiments of the rock cracking arrangement, the blocking material may be located in a package that is separate from the rock cracking cartridge. The package may be not connected to the rock cracking cartridge. Thereby, the material distribution device may be connected with the package.

[0028] In some embodiments the cartridge comprises the material distribution device. Further, the cartridge may comprise the blocking material. Thereby, the cartridge can provide the integrated functions of ignition of the powder change and blocking the hole towards the mouth.

[0029] Preferably, the cartridge comprises an elongated casing, and the ignition arrangement comprises a primer and a striker, wherein the powder charge and the primer are provided in the casing. Thereby, the striker may extend from inside the casing and protrude from the casing at an ignition end of the casing. Thereby the striker may protrude in the longitudinal direction of the casing. The striker is preferably arranged to be moved in relation to the casingin the longitudinal direction of the casing, so that the striker strikes the primer so that the primer ignites the powder charge.

[0030] Thereby, in embodiments of the method according to the invention, the striker is at the front when the cartridge is moved towards the bottom of the hole, whereby the striker collides with the bottom of the hole, so that the striker moves to strike the primer so that the primer ignites the powder charge.

[0031] The primer may form an igniter or detonator. As is well known per se, the primer is a small charge that acts as a trigger for the powder. The primer may form a mechanical detonator which ignites when subjected to an impact of the striker. The primer may be of any suitable kind, e.g. a center fire primer such as a Boxer primer or Berdan primer, or a rim fire primer.

[0032] The striker may comprise a firing pin extending in the longitudinal direction of the cartridge. The firing pin may be a solid rod. The firing pin may be fixed to a striker head which is located externally of the cartridge casing. Thereby, the collision of the striker with the bottom of the hole may be a collision of the striker head with the bottom of the hole. The cartridge casing may comprise an elongated tubular sleeve. The sleeve may be closed by a plug in the ignition end of the casing. The firing pin may extend through an opening in the plug. The striker may be held at a distance from the primer. The distance may be provided by a spring, or by a sacrificial part, such as a shoulder, which is adapted to break when subjected to the force pushing the striker towards the primer.

[0033] Reaching the object of the invention is also facilitated by a rock cracking cartridge comprising a rock cracking powder charge, the cartridge further comprising an ignition arrangement at a surface of the cartridge, wherein the ignition arrangement is adapted to ignite the powder charge when the ignition arrangement is subjected to a force directed towards the powder charge, wherein the cartridge further comprises blocking material which is located on a side of the powder charge which is opposite to the side of the powder charge on which the ignition arrangement is located. The cartridge may be elongated, and the ignition arrangement may be located at a longitudinal end of the cartridge. The blocking material may be located at the opposite longitudinal end of the cartridge. The cartridge may be adapted to be moved, with the ignition arrangement at the front, towards a bottom of a hole drilled in a stone or a part of a bedrock. The hole may extend from a mouth at a surface of the rock or the bedrock part andmay terminate inside the rock or the bedrock part. The ignition arrangement may be adapted to be subjected, by contact with the bottom of the hole, following the movement towards the bottom, to a force directed towards the powder charge whereby the powder charge is ignited. Thereby, the blocking material may be adapted to block the hole between the powder charge and the mouth of the hole.

[0034] As suggested above, and as exemplified below, the cartridge may be provided with a protection cap which covers the ignition arrangement, wherein the protection cap is adapted to break upon being subjected to a force towards the powder charge which is equal to or larger than a threshold force.

[0035] DESCRIPTION OF THE DRAWINGS

[0036] Below embodiments of the invention will be described with reference to the drawings in which,

[0037] fig. 1 shows a longitudinal cross-section of a rock cracking cartridge,

[0038] fig. 2 is a flow diagram depicting steps in a method according to an embodiment of the invention,

[0039] fig. 3 shows a vehicle with a drill and a rock depicted in a vertical cross-section, fig. 4 shows a vehicle with a compressed air shooter and the rock in fig. 3 depicted in a vertical cross-section,

[0040] fig. 5 and fig. 6 show longitudinal cross-sections of rock cracking cartridges, and packages with blocking material, to be used in respective alternative embodiments of the method,

[0041] fig. 7 shows a longitudinal cross-section of a package with blocking material, for use in a further embodiment of the method,

[0042] fig. 8 shows a longitudinal cross-section of a rock cracking cartridge according to another embodiment of the invention, and

[0043] fig. 9 - fig. 11 show a vehicle with a drill and a rock depicted in a vertical crosssection, for use with the cartridge in fig. 8.

[0044] DETAILED DESCRIPTIONFig. 1 shows a longitudinal cross-section of a rock cracking arrangement with a rock cracking cartridge 1 to be used in a method described below. The cartridge presents an outer surface 100. The cartridge comprises an elongated casing 101 and a rock cracking powder charge 102 in the casing. The casing 101 comprises a tubular sleeve 103. The tubular sleeve has a circular cross-section. The diameter of the sleeve may be 25-50 mm, e.g. 34 mm.

[0045] The cartridge 1 further comprises an ignition arrangement 104 at one end of the cartridge. The ignition arrangement comprises a primer 105 and a striker 106. The primer is located in the casing 101, between the powder charge 102 and the striker. The casing 101 comprises a plug 107 at an end of the casing, herein referred to as an ignition end 108. The casing and the plug form at least a part of the outer surface 100 of the cartridge. The striker 106 comprises a firing pin 109 which is fixed to a striker head 109a which is located externally of the cartridge casing 101. The firing pin extends through an opening in the plug 107. The striker 106 is held, e.g. by a spring, at a distance from the primer 105. When subjected to a force above a threshold force, the striker moves and strikes the primer. The primer ignites when subjected to an impact of the striker.

[0046] The cartridge 1 further comprises blocking material 110 on a side of the powder charge 102 which is opposite to the side of the powder charge on which the ignition arrangement 104 is located. The cartridge 1 also comprises a material distribution device 111 which is located between the powder charge 102 and the blocking material 110. The material distribution device Ill is tapered in a direction away from the powder charge. The functions of the blocking material and the material distribution device are described below.

[0047] With reference to fig. 2, a method for cracking a rock will be described. Even if this example includes the cracking of a block of stone, the method is, as mentioned, also useful for cracking a part of a bedrock.

[0048] As exemplified in fig. 3, the method comprises drilling SI a hole 201 into the rock 202 such that the hole extends from a mouth 203 at a surface of the rock and terminates inside the rock. The drilling is done with a drill 301 which is mounted on a vehicle 302. The drill 301 is mounted to vehicle 302 via a movable mounting arm 305. The vehicle and the drill may be remote controlled.As exemplified in fig. 4, the method further comprises providing S2 the cartridge 1 described above in a movement providing device 303. The movement providing device is mounted to a vehicle 304. The movement providing device is mounted to the vehicle 304 via the mounting arm 305. The vehicle and the movement providing device may be remote controlled. The movement providing device may be a shooter arranged to shoot the cartridge by means of compressed air, whereby the shooter may work according to a principle which corresponds to the working principle of an air shooter. The cartridge 1 may be placed in a barrel of the shooter. The cartridge is placed with the ignition arrangement 104 (fig. 1) in front as seen in the intended movement of the cartridge. The shooter is aimed into the hole, and aligned with the hole. The aiming of the shooter may be done by keeping the movable mounting arm 305 in its position while replacing the drill 301 with the shooter 303. In addition or alternatively, a camera may be used for the aiming. In some embodiments, the tip of the shooter is inserted into the hole.

[0049] Thereafter the cartridge 1 is by compressed air, or mechanically, e.g. by a spring, moved S3, or launched, into the hole 201 with the ignition arrangement at the front.

[0050] Thereby, the striker 106 (fig. 1) on the cartridge 1 collides with the bottom 204 of the hole 201, so that the striker moves to strike the primer 105 so that the primer ignites the powder charge 102, whereby the rock 202 will crack.

[0051] The blocking material 110 (fig. 1) prevents energy from the powder charge ignition escaping through the mouth 203 of the hole 201. The tapered shaped material distribution device 111 serves to spread the blocking material 110 sideways upon the impact of the cartridge 1 with the bottom 204 of the hole, so that the blocking function of the blocking material is augmented.

[0052] The diameter of the hole is preferably larger, e.g. 2-6 mm larger, than a diameter of the cartridge.

[0053] Fig. 5 shows a rock cracking arrangement to be used in an alternative embodiment of the method according to the invention. The rock cracking arrangement is similar to the one described with reference to fig. 1, except for the following: The cartridge 1 does not compriseany blocking material. Instead, blocking material 110 is provided in a separate package 112. The package may be solid, or flexible like a bag. When the cartridge 1 is moved or launched towards the bottom of the hole, the package 112 with the blocking material is moved simultaneously, behind the cartridge. When the cartridge 1 collides with the bottom 204 of the hole 201, the package 112 collides with the rear end of the cartridge, which is provided with the material distribution device 111 which is tapered in a direction away from the powder charge 102. Upon the collision and the explosion of the powder, the tapered shaped material distribution device 111 serves to spread the blocking material 110 sideways.

[0054] Fig. 6 shows a rock cracking cartridge 1 with blocking material, which is similar to the one shown in fig. 1, except for that there is no material distribution device 111 in the cartridge.

[0055] Fig. 7 shows a package 112 with blocking material 110 which is separate from a rock cracking cartridge (not shown). The package is intended to be moved towards the bottom of a hole drilled as described above, behind the rock cracking cartridge. The package is solid, and comprises a casing which may be tube shaped. In addition to the blocking material, the package contains a material distribution device 111. The material distribution device 111 is thereby connected to the package. The material distribution device 111 may be intended to be located, when used, between the rock cracking cartridge and the blocking material 110.

[0056] Alternatively, the blocking material 110 may be intended to be located, when used, between the rock cracking cartridge and the material distribution device 111.

[0057] Fig. 8 shows a longitudinal cross-section of a rock cracking arrangement with a rock cracking cartridge 1 according to another embodiment of the invention. The cartridge is to be used in a method according to another embodiment of the invention, described below. The cartridge has similarities with the cartridge described with reference to fig. 1, and the method has similarities with the method described with reference to fig. 2 - fig. 4. Here, the differences will be focused on.

[0058] Differing from the cartridge in fig. 1, in the cartridge in fig. 8, the blocking material 110 is located between the material distribution device 111 and the powder charge 102. Thereby, the material distribution device 111 is located at an end of the cartridge which is opposite to the ignition end 108. Also, the material distribution device 111 is tapered in a direction towards the powder charge. The function of the material distribution device is described below.Also, at the ignition end, the cartridge is provided with a protection cap 113. The protection cap covers the ignition arrangement 104. The protection cap 113 prevents accidental actuation of the ignition arrangement 104. The protection cap 113 may be made in a plastic material. The protection cap may be adapted to break upon being subjected to a threshold force, e.g. of at least 500 N, towards the powder charge. Such breaking is described further below.

[0059] Reference is made also to fig. 9. Similar to the method described with reference to fig. 2 - fig.

[0060] 4, the method, in which the cartridge in fig. 8 is used, comprises drilling a hole 201 into a rock 202 with a drill 301. The drill is held by a drill holding device 306. The drill holding device is mounted to a movable mounting arm 305. The mounting arm 305 is mounted to a vehicle 302. A drill stabilising device 308 is mounted to the drill holding device 306, and is arranged to be in contact with the rock 202. There, the drill stabilising device 308 serves to stabilise the position of the drill in relation to the rock.

[0061] The cartridge 1 is provided in a cartridge holder 307. The cartridge holder 307 is mounted to the drill holding device 306.

[0062] Reference is made also to fig. 10. When the hole has been drilled, the drill 301 is retracted out of the hole. The cartridge 1 is moved so as to rest on a cartridge support device 309. The cartridge support device 309 is mounted on the drill holding device 306. Thereby, the cartridge is located between the hole 201 and the drill 301. Further, the cartridge is aligned with the hole. In some embodiments, the drill holding device 306 is integrated with the cartridge holder 307.

[0063] Reference is made also to fig. 11. Thereafter, the cartridge 1 is pushed by the drill 301 into the hole 201, with the ignition arrangement at the front. When the cartridge reaches the bottom 204 of the hole, the drill 301 pushes the cartridge towards the bottom of the hole, so that the protection cap 113 (fig. 8) breaks and the ignition arrangement 104 (fig. 8) is actuated, whereby the powder charge is ignited and the rock 202 will crack. Thereby, the drill works as a pushing device pushing the cartridge towards the bottom of the hole. Alternatively, another device, e.g. an elongated bar, may serve as a pushing device pushing the cartridge towards the bottom of the hole.Alternatively, where the hole is directed partly downwards towards the bottom of the hole, the cartridge can slide into the hole, to the bottom of the hole. Thereby, the protection cap 113 (fig. 8) may prevent actuation of the ignition arrangement 104 when the cartridge reaches the bottom of the hole. Thereafter, the cartridge 1 is pushed by the pushing device, e.g. the drill 301, towards the bottom of the hole, so that the protection cap 113 (fig. 8) breaks and the ignition arrangement 104 (fig. 8) is actuated, whereby the powder charge is ignited and the rock 202 will crack.

[0064] The blocking material 110 (fig. 8) prevents energy from the powder charge ignition escaping through the mouth 203 of the hole 201. A further blocking function is provided by the drill 301. Nevertheless, the blocking material 110 serves to protect the drill from immediate exposure to the blast of the powder charge. The blast of the powder charge biases the blocking material towards the drill 301. Thereby, the tapered shaped material distribution device 111 serves to spread the blocking material 110 sideways upon the blast of the powder charge, so that the blocking function of the blocking material is augmented.

Claims

CLAIMS1. A method for cracking a rock or a part of a bedrock, comprisingdrilling a hole (201) into the rock (202) such that the hole extends into the rock or the bedrock part from a mouth (203) at a surface of the rock or the bedrock part, providing a rock cracking cartridge (1) comprising a rock cracking powder charge (102), the cartridge further comprising an ignition arrangement (104), wherein the ignition arrangement is adapted to ignite the powder charge (102) when the ignition arrangement is subjected to a force directed towards the powder charge, moving the cartridge (1) towards a bottom of the hole (201) with the ignition arrangement (104) at the front, and subjecting, by contact with the bottom (204) of the hole, the ignition arrangement to a force directed towards the powder charge (102) whereby the powder charge is ignited,- wherein the method comprises, while moving the cartridge (1) towards the bottom of the hole (201), moving blocking material (110) behind the powder charge (102) to block the hole (201) between the powder charge and the mouth (203) of the hole, wherein the rock cracking cartridge (1) comprises the blocking material (HO).

2. A method according to claim 1, wherein moving the cartridge (1) towards the bottom of the hole comprises moving the cartridge (1) into the hole (201).

3. A method according to any one of the preceding claims, wherein the force that the ignition arrangement is subjected to is provided by a collision of the cartridge with the bottom of the hole (201).

4. A method according to any one of the preceding claims, wherein the step of moving the cartridge (1) towards the bottom of the hole (201) is done by means of compressed air, by hydraulic means, or mechanically, such as with a spring.

5. A method according to any one of the preceding claims, wherein subjecting the ignition arrangement to the force directed towards the powder charge (102) is done by means of a pushing device (301) pushing the cartridge towards the bottom of the hole.

6. A method according to claim 5, wherein the step of drilling the hole (201) is done by means of a drill (301), wherein the drill is used as the pushing device.

7. A method according to any one of the preceding claims, wherein the cartridge (1) comprises a material distribution device (111) located on a side of the powder charge (102) which is opposite to the side of the powder charge on which the ignition arrangement (104) is located, which material distribution device (111) is tapered, so that upon the ignition arrangement being subjected to the force directed towards the powder charge, the tapered shape of the material distribution device (111) forces the blocking material (110) outwards, laterally to the longitudinal direction of the hole.

8. A method according to any one of the preceding claims, wherein the rock to be cracked is a block of stone, and the hole (201) is drilled such that it extends at least 50% through the block of stone.

9. A method according to any one of the preceding claims, wherein the rock to be cracked is a block of stone, and the hole (201) extends no more than 80% through the block of stone, preferably no more than 75% through the block of stone.

10. A rock cracking arrangement comprising a rock cracking cartridge (1) comprising a rock cracking powder charge (102), the cartridge further comprising an ignition arrangement (104) at a surface of the cartridge, wherein the ignition arrangement is adapted to ignite the powder charge when the ignition arrangement is subjected to a force directed towards the powder charge, wherein the rock cracking arrangement comprises a material distribution device (111) which is intended to be located, when the rock cracking arrangement is used, on a side of the powder charge (102) which is opposite to the side of the powder charge on which the ignition arrangement (104) is located, which material distribution device (111) is tapered.

11. A rock cracking arrangement according to claim 10, wherein the rock cracking arrangement further comprises blocking material (110) which is intended to be located, when the rock cracking arrangement is used, on a side of the powder charge (102) which is opposite to the side of the powder charge on which the ignition arrangement (104) is located.1612. A rock cracking arrangement according to claim 11, wherein the rock cracking cartridge comprises the blocking material (110).

13. A rock cracking arrangement according to any one of claims 10-12, wherein the cartridge comprises the material distribution device (111).

14. A rock cracking arrangement according to any one of claims 10-13, wherein the cartridge comprises an elongated casing (101), and the ignition arrangement (104) comprises a primer (105) and a striker (106), wherein the powder charge (102) and the primer are provided in the casing, wherein the striker extends from inside the casing (101) and protrudes from the casing at an ignition end of the casing, the striker (106) being arranged to be moved in relation to the casing (101) in the longitudinal direction of the casing, so that the striker strikes the primer (105) so that the primer ignites the powder charge.

15. A rock cracking cartridge (1) comprising a rock cracking powder charge (102), the cartridge further comprising an ignition arrangement (104) at a surface of the cartridge, wherein the ignition arrangement is adapted to ignite the powder charge when the ignition arrangement is subjected to a force directed towards the powder charge, wherein the cartridge further comprises blocking material (110) which is located on a side of the powder charge (102) which is opposite to the side of the powder charge on which the ignition arrangement (104) is located.

16. A rock cracking cartridge according to claim 15, wherein the cartridge is provided with a protection cap (113) which covers the ignition arrangement (104), wherein the protection cap is adapted to break upon being subjected to a force towards the powder charge which is equal to or larger than a threshold force.

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