BLASTING SYSTEM AND A METHOD OF EXPLOSIVE MATERIAL CHARGING

Abstract

The invention concerns a blasting system (1) configured for explosive material charging in a borehole (3). The system (1) comprises a detonator support device (5) configured to be inserted into the borehole (3) by means of a charging hose (7); a main body (9) of the detonator support device (5) comprises a channel (8) oriented along a main body centre line (CL) extending along the borehole extension during said explosive material charging; an openable cover device (14) covering the channel (8) is configured to come into contact with the charging hose (7) in motion for pushing the main body (9) along the borehole (3), wherein the charging hose (7) in motion is configured to open the openable cover device (14) whilst a stopping arrangement (13) stops the main body (9).

The invention also concerns a method of explosive material charging in a borehole (3) by means of the blasting system (1).

Claims

1. (canceled)

2. A detonator support device configured for explosive material charging in a borehole, the detonator support device comprising: a main body, the main body comprising: a first end and a second end, the first end facing an entrance of the borehole, and the second end facing a deep end of the borehole; and a channel oriented along a center line of the main body, the channel comprising an openable cover; and a detonator unit compartment configured to support a detonator unit, the detonator unit compartment positioned adjacent a side wall of the detonator support device.

3. The detonator support device of claim 2, comprising a stop coupled to the detonator support device.

4. The detonator support device of claim 3, wherein the stop includes a dimension larger than a diameter of the borehole.

5. The detonator support device of claim 2, comprising a backflow prevention valve configured to inhibit discharge of explosive material.

6. The detonator support device of claim 5, wherein the backflow prevention valve is configured to provide a closing of a flap member of the backflow prevention valve subsequent to withdrawn of a charging hose from the backflow prevention valve.

7. The detonator support device of claim 6, wherein the flap member of the backflow prevention valve is spring biased for providing said closing, preventing the explosive material above the backflow prevention valve to stream downward.

8. The detonator support device of claim 2, comprising a charging hose.

9. The detonator support device of claim 8, wherein the charging hose configured to open the cover from a closed position to an open position.

10. The detonator support device of claim 2, wherein the openable cover comprises an extension configured to extend in an orientation substantially perpendicular to the center line of the main body.

11. The detonator support device of claim 2, wherein the detonator unit compartment comprises a compartment opening, the compartment opening facing a deep end of the borehole.

12. The detonator support device of claim 2, wherein the detonator unit compartment is configured to exhibit a prolongation extending parallel with a prolongation of the channel.

13. The detonator support device of claim 2, further comprising a detonation cord member.

14. The detonator support device of claim 13, wherein the detonation cord member is one of shock tube or detonation cord.

15. The detonator support device of claim 13, wherein the detonation cord is coupled to the detonator unit and runs from the detonator unit positioned in the detonator unit compartment.

16. The detonator support device of claim 2, wherein the main body comprises a resilient member extending circumferentially around the main body.

17. The detonator support device of claim 16 wherein the resilient member is arranged to an outer peripheral surface of the main body and around the center line of the main body.

18. The detonator support device of claim 16, wherein the resilient member runs discontinuously around the main body.

19. The detonator support device of claim 2, wherein the openable cover is movable from an open position to a closed position.

20. A detonator support device configured for use in a blasting system in a borehole, comprising: a main body comprising a first end and a second end, the first end facing an entrance of the borehole, and the second end facing a deep end of the borehole; a detonator unit compartment configured to support a detonator unit; and a backflow prevention valve positioned at the first end of the main body, the backflow prevention valve comprising a biasing member configured to move the backflow prevention valve from an open position to a closed position.

21. The detonator support device of claim 20, further comprising a splitable cover member positioned at the second end of the main body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0093] The present invention will now be described by way of examples with references to the accompanying schematic drawings, of which:

[0094] FIGS. 1a-1d illustrate a blasting system according to a first example;

[0095] FIG. 2 illustrates in a side view a detonator support device of a blasting system according to a second example;

[0096] FIG. 3 illustrates from above a detonator support device of a blasting system according to a third example;

[0097] FIG. 4 illustrates in a side view a detonator support device of a blasting system according to a fourth example;

[0098] FIG. 5 illustrates from above a detonator support device of a blasting system according to a fifth example;

[0099] FIG. 6 illustrates in a side view a detonator support device of a blasting system according to a sixth example;

[0100] FIG. 7 illustrates from above a detonator support device of a blasting system according to a seventh example;

[0101] FIG. 8 illustrates in a side view a detonator support device of a blasting system according to an eight example;

[0102] FIGS. 9a-9b illustrate in a side view a detonator support device of a blasting system according to a ninth example;

[0103] FIG. 10 illustrates a flowchart showing an exemplary method of explosive material charging in a borehole;

[0104] FIG. 11 illustrates a flowchart showing an exemplary method of explosive material charging in a borehole;

[0105] FIG. 12 illustrates an explosive material charging vehicle configured to perform an exemplary method of explosive material charging in a borehole;

[0106] FIG. 13 illustrates a control circuitry adapted to operate an explosive material charging vehicle configured to perform an exemplary method of explosive material charging in a borehole;

[0107] FIG. 14a illustrates an exemplary detonator support of a blasting system in perspective view; and

[0108] FIG. 14b illustrates stackable detonator support devices.

DETAILED DESCRIPTION

[0109] Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings, wherein for the sake of clarity and understanding of the invention some details of no importance may be deleted from the drawings.

[0110] FIGS. 1a-1d illustrate a blasting system 1 according to a first example configured for explosive material charging in a borehole 3. The blasting system 1 comprises a detonator support 5 configured to be inserted into the borehole 3 by means of a charging hose 7. A main body 9 of the detonator support 5 comprises a channel (not shown) oriented along a main body centre line CL extending along the borehole extension during said explosive material charging. A crack 11 in the rock feeds ground water to the borehole 3. An openable cover (not shown) covering the channel is configured to come into contact with the charging hose 7 in motion for pushing the main body 9 along the borehole 3. The charging hose 7 in motion is configured to open the openable cover device whilst a stopping arrangement 13 stops the main body 9 as shown in FIG. 1b. A detonator unit compartment (not shown) is provided in the main body 9 adjacent the channel and is configured to support a detonator unit 15. The stopping arrangement 13 has a line assembly 17 arranged between the main body 9 and a stop rod 18 configured to abut the borehole entrance 19. An operator (not shown) can thus easily set the length of the line assembly 17 corresponding with the length L of the uncharged part of the borehole 3 based on a charging plan. The operator simply may make a knot at the line assembly 17 for proving proper length L. Preferably, the stop rod 18 (such as a timber stick) may be 2-4 times longer than the diameter of the borehole 3. A charging hose nozzle 21 of the charging hose 7 discharges the explosive material 23 into the borehole 3 above the main body 9 by pumping the explosive material 23 by means of a pump 25. Also the channel (not shown) of the main body 9 will be filled with the explosive material 23 that has been charged into the borehole above the main body 9, as seen in FIG. 1c, by that the explosive material streams downward due to gravity through the opened openable cover (not shown) and further downward into the channel of the main body 9. The explosive material 23 is obstructed to flow beyond the channel by means of a backflow prevention valve (not shown). In FIG. 1d is shown that the charging hose 7 fully has been withdrawn from the borehole 3 and the main body 9 of the blasting system 1 holds the explosive material 23 above the main body 9 and in contact with the detonator unit 5. The detonator unit 15 is connected to a controller 27.

[0111] FIG. 2 illustrates in a side view a detonator support 5 of a blasting system according to a second example. A main body 9 of the blasting system comprise a detonator support 5 configured to be inserted into a borehole (not shown) by means of a charging hose (not shown). The main body 9 of the detonator support 5 comprises a channel 8 oriented along a main body centre line CL extending along the borehole extension during said explosive material charging. A splitable cover 14 covering the channel 8 is configured to come into contact with the charging hose in motion for pushing the main body 9 along the borehole.

[0112] Alternatively, a backflow prevention valve 16 is positioned at a first end 31 of the main body 9 and is curved so that a valve flap 20 in opened position extends along the curvature of the channel 8, which implies that the charging hose can fill out the space optimally within the channel 8, thus providing a compact detonator support 5.

[0113] The charging hose in motion is configured to open the splitable cover 14 of an upper opening at a second end 31 of the main body 9, whilst a stopping arrangement 13 stops the main body (as shown in FIG. 1b). A detonator unit compartment 33 is provided in the main body 9 adjacent the channel 8 and is configured to support a detonator unit 15.

[0114] The backflow prevention valve 16 is configured to prevent discharged explosive material (not shown), discharged from the charging hose, to pass the channel 8 and below the channel when the charging hose has been removed from the upper opening 10 and removed from the backflow prevention valve 16.

[0115] The backflow prevention valve 16 is hingedly arranged about a hinge 35 and is spring biased to a closed state by means of a spring 37.

[0116] The main body 9 comprises a plurality of resilient flanges 39 extending circumferentially around the main body 9 and is arranged to an outer peripheral surface 41 of the main body 9 and around the main body centre axis CL. The resilient flanges 39 extend discontinuously around the main body 9 and is adapted to engage the borehole wall of the borehole and biased into secure engagement with the borehole wall. The resilient flanges 39 are made of flexible material and is tooth shaped with open spaces 43 there between.

[0117] In such way is achieved that water is permitted to pass the exterior of the main body 9, thus between the borehole wall and the outer peripheral surface 41 of the main body 9 and passing through the open spaces 43. In such way is avoided that high water pressure is built up above the main body 9, which water pressure otherwise would press out the main body 9 from the borehole and releasing the explosive material from the borehole to the crosscut floor (not shown). The blasting system thus allows ground water and remaining drill cooling water to drain by the provision that the main body 9 does not completely seal the borehole.

[0118] The upper part of the main body may have thinner wall than the lower part of the main body 9 to increase the structural strength of the main body 9 and to optimise the design of the splitable cover 14 of the upper opening of the second end 31.

[0119] The tooth shaped resilient flanges 39 may be formed as anchoring wings having notches 45 configured to guide and protect a shock tube 44 and/or a detonation cord 44 running from the detonator unit 15 and through the borehole into the crosscut.

[0120] FIG. 3 illustrates from above a detonator support 5 of a blasting system according to a third example. A main body 9 comprises a channel 8 oriented along the main body centre line. A backflow prevention valve flap 20 of a non-return valve 16 positioned at a first end of the main body 9. The backflow prevention valve flap 20 is spring based into closed position by means of a spring 37.

[0121] Alternatively, a charging hose (not shown) in motion is configured to open the backflow prevention valve flap 20 and subsequently open a splitable cover 14 at a second end of the main body 9, whilst a stopping arrangement (not shown) stops the main body 9 (as shown in FIG. 1b) to be pushed further, whereas a charging hose nozzle (not shown) of the charging hose penetrates and breaks the splitable cover 14 to directly face the borehole (above the main body 9) to be filled with explosive material.

[0122] A detonator unit compartment 33 is provided in the main body 9 adjacent the channel 8 and is configured to support a detonator unit 15.

[0123] The main body 9 comprises resilient flanges 39 extending circumferentially around the main body 9 and is arranged to an outer peripheral surface 41 of the main body 9 and around the main body centre axis. The resilient flanges 39 extend discontinuously around the main body 9 and is adapted to engage the borehole wall of the borehole and biased into secure engagement with the borehole wall. The resilient flanges are made of flexible material and is tooth shaped with open spaces 43 there between.

[0124] FIG. 4 illustrates in a side view a detonator support 5 of a blasting system according to a fourth example. A main body 9 of the detonator support comprises a resilient flange arrangement having three rows of teeth. This example uses a backflow prevention valve divided in two closable flaps 20, 20. In FIG. 4 is shown a position being settled for explosive material discharge from a charging hose nozzle 21 of a charging hose 7. An upper portion 46 of the charging hose 7 is accommodated in the channel 8 of the main body 9. The resilient flanges formed as teeth exhibit sloping outward extension relative the main body centre line of 30-70 degrees, preferably 45-60 degrees, and declining toward the first end 31 of the main body 9.

[0125] FIG. 5 illustrates from above a detonator support 5 of a blasting system according to a fifth example. A set of nets 61 or other suitable filters have been arranged in the open spaces 43 of the resilient flanges 39 for capturing gravel, sand and other particles from falling down to the crosscut floor. Primarily, the water passes through the open spaces 43 of the resilient flanges 39.

[0126] FIG. 6 illustrates in a side view a detonator support 5 of a blasting system according to a sixth example. A main body 9 of the detonator support 5 comprises an upper and lower wave-shaped flexible rubber braid or rim 39, which are configured to engage the borehole wall. A channel 8 of the main body 9 is formed to receive a charging hose nozzle. A pair of tubes are provided to be adjacent the borehole wall for the release of the water pressure in the charged borehole. Alternatively, the braid or rim 39 may have holes.

[0127] FIG. 7 illustrates from above a detonator support 5 of a blasting system according to a seventh example. The detonator support 5 has two elastic flanges 39 with a plurality of holes 62 arranged for decreasing the water pressure.

[0128] FIG. 8 illustrates in a side view a detonator support 5 of a blasting system according to an eight example. FIG. 8 shows water w flowing along the borehole wall 4 of the borehole 3. As shown, the main body 9 is engaged to the borehole wall 4 by means of the resilient flanges 39 being in contact with the borehole wall 4. The engagement force of the resilient flanges 39 generates sufficient friction resisting motion of the main body 9 relative the borehole, which motion otherwise would prevail due to gravity and pressure of explosive material 23 and water pressure, and thus holding the explosive material 23 in the borehole 3 at the same time as the water can flow through the open spaces 43 of the resilient flanges.

[0129] FIGS. 9a-9b illustrate in a side view a detonator support 5 of a blasting system according to a ninth example. As shown in FIG. 9a, the charging hose nozzle 21 has pushed the main body upward in the bore hole by that the free end of the nozzle abuts an openable lid L. The openable lid L is closable by means of a biasing force of enough amount to permit said pushing. When the line arrangement stops the motion of the main body, the nozzle opens the lid L. A detonator unit 15 is positioned on an upper side of the main body so that good contact between the detonator unit and the explosive material is achieved. A shown in FIG. 9b, the charging hose nozzle has been removed and the openable lid L has closed by means of said biasing force and the explosive material 23 is obstructed to flow downward.

[0130] FIG. 10 illustrates a flowchart showing an exemplary method of explosive material charging in a borehole by means of a blasting system 1. The blasting system comprises a detonator support configured to be inserted into the borehole by means of a charging hose. A main body of the detonator support comprises a channel oriented along a main body centre line extending along the borehole extension during said explosive material charging. An openable cover covering the channel is configured to come into contact with the charging hose in motion for pushing the main body along the borehole. The charging hose in motion is configured to open the openable cover device whilst a stopping arrangement stops the main body as e.g. shown in FIG. 1b.

[0131] The method comprises a first step 101 starting the method. A second step 102 shows the performance of the method. A third step 103 comprises stopping the method.

[0132] The second step 102 may comprise; providing the detonator support device coupled to the stopping arrangement; preparing a detonator unit to be coupled to a detonation cord member; mounting the detonator unit to the detonator support device; inserting the detonator support device into the borehole; pushing the detonator support device by the charging hose; stopping the detonator support device by means of the stopping arrangement; opening the openable cover device by further motion of the charging hose; charging the explosive material into the borehole; and removing the charging hose.

[0133] FIG. 11 illustrates a flowchart showing an exemplary method of explosive material charging in a borehole by means of a blasting system. The method comprises a first step 111 starting the method. A second step 112 comprises that the opening step is configured to split or break a splitable cover member by means of a charging hose nozzle of the charging hose in motion. A third step 113 comprises the step of removing the charging hose comprises withdrawing of the charging hose from the openable cover device. A fourth step 114 comprises that the step of pushing the detonator support is preceded by a step that the charging hose enters and pass a backflow prevention valve and subsequently abuts a splitable cover member of the openable cover device for providing said pushing. A fifth step 115 comprises that the step of stopping the detonator support device and the step of opening the openable cover device being performed simultaneously, wherein the splitable cover member splits or breaks by the charging hose (i.e. by the charging hose nozzle) being moved further upward. A sixth step 116 comprises stop moving the charging hose. A seventh step 117 comprises discharging of explosive material from the charging hose nozzle into the borehole above the main body of the detonator support. An eight step 118 comprises stopping the discharge of explosive material. A ninth step 119 comprises withdrawal of the charging hose from the borehole. A tenth step 120 comprises stopping the method.

[0134] Alternatively, the operating procedure may be as follows; the operator places the detonator unit in the predefined location in the main body and sets a pre-determined length of the line assembly.

[0135] Subsequently, the operator may position the main body onto the charging hose nozzle of the charging hose.

[0136] Then the line arrangement is tensioned and since the strength of line arrangement is stronger than that of the splitable cover member, against which the charging hose nozzle abuts when pushing the main body upward, the charging hose nozzle will split or remove the splitable cover member from the main body.

[0137] The charging hose nozzle is preferably moved further upward into the borehole, whereby the splitable cover member breaks apart in several small pieces. These parts are preferably small enough, so they do not create any clogging or stopping of the charging process.

[0138] The inventor of the present disclosure makes use of the fact that the water pressure applied to the explosive material from above tends to form water streams streaming along the borehole wall of the borehole.

[0139] Alternatively, the resilient member arranged on the outer peripheral surface of the main body comprises at least one open space through which the water stream streaming along the borehole wall will drain.

[0140] In such way is achieved that the main body not will be pushed out from the borehole. Additionally, since the water makes water streams flowing along the borehole wall, the explosive will also gain some further adhesion to the borehole wall. This adhesion takes away some of the load of the main body in engagement with the borehole wall.

[0141] The explosive material at the vicinity of the detonator support device is under pressure by its own weight. The explosive is a hydrophobic material due to oil content and the water will flow toward the lowest pressure point, which is at the at least one open space of the resilient member of the detonator support device.

[0142] FIG. 12 illustrates an explosive material charging vehicle 77 configured to perform an exemplary method of explosive material charging in a borehole 3. The explosive material charging vehicle 77 comprises a robotic arm 78 and a charging hose feeder 79, which are coupled to a control circuitry (not shown, reference 50, see FIG. 13) of the explosive material charging vehicle 77. The control circuitry is configured to control the exemplary method or methods as disclosed herein. The control circuitry comprises a data medium, configured for storing a data program, configured for controlling the blasting system 1 of the explosive material charging vehicle 77. The data medium comprises a program code stored on the data medium, which program code is readable on the control circuitry for performing the method steps.

[0143] FIG. 13 illustrates a control circuitry 50 adapted to operate an explosive material charging vehicle (e.g. shown in FIG. 12) configured to perform an exemplary method of explosive material charging in a borehole. The control circuitry 50 is coupled to an actuator arrangement (not shown) of a robotic arm (not shown) of the explosive material charging vehicle. The control circuitry 50 is configured to perform the method of explosive material charging in a borehole by means of a blasting system comprising a detonator support device configured to be inserted into the borehole by means of a charging hose; a main body of the detonator support device comprises a channel oriented along a main body centre line extending along the borehole extension during said explosive material charging; an openable cover device covering the channel is configured to come into contact with the charging hose in motion for pushing the main body along the borehole, wherein the charging hose in motion is configured to open the openable cover device whilst a stopping arrangement stops the main body. The method comprises providing the detonator support device coupled to the stopping arrangement and preparing a detonator unit to be coupled to a detonation cord member. It further comprises mounting the detonator unit to the detonator support device and successively inserting the detonator support device into the borehole. The method comprises pushing the detonator support device by the charging hose, stopping the detonator support device by means of the stopping arrangement; opening the openable cover device by further motion of the charging hose; charging the explosive material into the borehole; and removing the charging hose.

[0144] The control circuitry 50 may also be configured for manoeuvring the explosive material charging vehicle in the crosscut of the mine (not shown).

[0145] The control circuitry 50 may comprise a computer and a non-volatile memory NVM 1320, which is a computer memory that can retain stored information even when the computer is not powered.

[0146] The control circuitry 50 further comprises a processing unit 1310 and a read/write memory 1350. The NVM 1320 comprises a first memory unit 1330. A computer program (which can be of any type suitable for any operational data) is stored in the first memory unit 1330 for controlling the functionality of the control circuitry 5. Furthermore, the control circuitry 50 comprises a bus controller (not shown), a serial communication unit (not shown) providing a physical interface, through which information transfers separately in two directions.

[0147] The control circuitry 50 may comprise any suitable type of I/O module (not shown) providing input/output signal transfer, an A/D converter (not shown) for converting continuously varying signals from a sensor arrangement (not shown) of the control circuitry 50 configured to determine the actual position of the robotic arm and the charging hose. The control circuitry 50 is configured to, from received control signals, define actual positions of the robotic arm and operation of the explosive material charging vehicle into binary code suitable for the computer, and from other operational data.

[0148] The control circuitry 50 also comprises an input/output unit (not shown) for adaptation to time and date. The control circuitry 50 comprises an event counter (not shown) for counting the number of event multiples that occur from independent events in operation of the explosive material charging vehicle.

[0149] Furthermore, the control circuitry 50 includes interrupt units (not shown) associated with the computer for providing a multi-tasking performance and real time computing for semi-automatically and/or autonomous maneuvering the explosive material charging vehicle. The NVM 1320 also includes a second memory unit 1340 for external sensor check of the sensor arrangement.

[0150] A data medium for storing a program P may comprise program routines for automatically adapting the maneuvering of the explosive material charging vehicle in accordance with operational data of co-operative explosive material charging vehicles (not shown).

[0151] The data medium for storing the program P comprises a program code stored on a medium, which is readable on the computer, for causing the control circuitry 50 to perform the method and/or method steps described herein.

[0152] The program P further may be stored in a separate memory 1360 and/or in the read/write memory 1350. The program P, in this embodiment, is stored in executable or compressed data format.

[0153] It is to be understood that when the processing unit 1310 is described to execute a specific function that involves that the processing unit 1310 may execute a certain part of the program stored in the separate memory 1360 or a certain part of the program stored in the read/write memory 1350.

[0154] The processing unit 1310 is associated with a data port 999 for communication via a first data bus 1315 able to be coupled to the robotic arm and the charging hose feeder 79 for performing said method steps.

[0155] The non-volatile memory NVM 1320 is adapted for communication with the processing unit 1310 via a second data bus 1312. The separate memory 1360 is adapted for communication with the processing unit 610 via a third data bus 1311. The read/write memory 1350 is adapted to communicate with the processing unit 1310 via a fourth data bus 1314. After that the received data is temporary stored, the processing unit 1310 will be ready to execute the program code, according to the above-mentioned method.

[0156] Preferably, the signals (received by the data port 999) comprise information about operational status of the explosive material charging vehicle. The received signals at the data port 999 can be used by the control circuitry 50 for controlling and monitoring automatic calibration of the sensor device 1.

[0157] Information and data may be manually fed, by an operator, to the control circuitry via a suitable communication device, such as a computer display or a touchscreen.

[0158] The method can also partially be executed by the control circuitry 50 by means of the processing unit 1310, which processing unit 1310 runs the program P being stored in the separate memory 1360 or the read/write memory 1350. When the control circuitry 50 runs the program P, the suitable method steps disclosed herein will be executed.

[0159] Alternatively, the charging hose in motion is configured to open the openable cover device whilst a stopping arrangement (not shown) of the robotic arm stops the main body.

[0160] FIG. 14a illustrates an exemplary detonator support 5 of a blasting system in perspective view.

[0161] A main body 9 of the detonator support 5 comprises a resilient flange 39F extending circumferentially around the main body 9 and is arranged to an outer peripheral surface 41 of the main body 9 and around the main body centre axis CL. A detonator unit compartment 33 is provided in the main body 9, which detonator unit compartment 33 being adjacent a side wall of the detonator support 5. The main body 9 of the detonator support 5 comprises a resilient flange arrangement having three rows of resilient flanges 39F. Each resilient flange 39F extend circumferentially around the main body 9 and is arranged to an outer peripheral surface 41 of the main body 9 and around the main body centre axis CL. The resilient flanges 39F extend continuously around the main body 9 and are adapted to engage the borehole wall (not shown) of a borehole (not shown). The resilient flanges 39F are biased toward the borehole wall for holding the detonator support 5 in rigid position in the borehole.

[0162] The water pressure built up above the main body 9 does not have sufficient force to move the detonator support 5 in the borehole due to the resilient flanges 39F biased toward the borehole wall. The spring biasing resilient flanges 39F hold the main body 9 in position in the borehole and the water pressure does not press out the main body 9 from the borehole, thus eliminating the risk of releasing explosive material from the borehole.

[0163] The resilient flanges 39F generate sufficient friction resisting action of the main body relative the borehole. In such way the detonator support 5 is prevented from being ejected from the borehole, due to gravity and the weight/pressure of explosive material and water.

[0164] The resilient flanges 39F are made of flexible material (e.g. plastic).

[0165] Alternatively, each resilient flange 39F may comprise at least one slot 40F (dotted lines). Such set of slots 40F may be used to guide a detonation cord (not shown) outside the main body 9.

[0166] FIG. 14b illustrates detonator supports 5 that are stacked on one another. The number of stacked detonator supports 5 may depend on desired resisting force of the stack for holding the stack in position preventing water and explosive material. A detonator unit may be positioned in each end of the stack or in each detonator support. The detonator units may be coupled to each other via a detonator cord (not shown).

[0167] An upper part (during use of the stack) of the detonator supports 5 may comprise a protrusion or a depression and a lower part of the detonator supports 5 may comprise a depression or a protrusion, which depression and protrusion mate with each other for joining adjacent detonator supports 5 to each other.

[0168] The present invention is of course not in any way restricted to the preferred embodiments described above, but many possibilities to modifications, or combinations of the described embodiments thereof should be apparent to a person with ordinary skill in the art without departing from the basic idea of the invention as defined in the appended claims.