CA1236987A - Method of rock bolting, and a device, and a roof bolting apparatus - Google Patents
Method of rock bolting, and a device, and a roof bolting apparatusInfo
- Publication number
- CA1236987A CA1236987A CA000455419A CA455419A CA1236987A CA 1236987 A CA1236987 A CA 1236987A CA 000455419 A CA000455419 A CA 000455419A CA 455419 A CA455419 A CA 455419A CA 1236987 A CA1236987 A CA 1236987A
- Authority
- CA
- Canada
- Prior art keywords
- grout
- borehole
- nozzle
- ejected
- jet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- On-Site Construction Work That Accompanies The Preparation And Application Of Concrete (AREA)
Abstract
Abstract:
In roof bolting, when an anchor rod (24) is to be inserted in a borehole (26) in the rock, a cement grout is ejected as a jet from a nozzle (22) located at the mouth of the borehole to partially fill the hole before the rod is forced into the borehole. The jet of grout should have such a velocity that it reaches the bottom of the borehole. A grout pump (45, 60) forces the grout through a hose (28) to the nozzle (22).
In roof bolting, when an anchor rod (24) is to be inserted in a borehole (26) in the rock, a cement grout is ejected as a jet from a nozzle (22) located at the mouth of the borehole to partially fill the hole before the rod is forced into the borehole. The jet of grout should have such a velocity that it reaches the bottom of the borehole. A grout pump (45, 60) forces the grout through a hose (28) to the nozzle (22).
Description
~36~
This invention relates to a method of rock bolting in which a hole is drilled in the rock, a batch of bulk yrout is introduced into the borehole and an anchor rod is forced into the borehole. The invention relates also to a device for carrying out the introduction of grout in the borehole and to a roof bolting apparatus.
In US-A-4158520, a roof bolting apparatus is shown which comprises a rock drill, a bolt setting machine, and a loading device for two-component resin cartridges. The resin cartridges are blown into the borehole and their contents are mixed by the bolt to a hardening mass. In G~-A-953056, cartridges for roof bolting are described which contain a dry cement mortar and a separate compartment of water. It is also known to insert a hose to the bottom of the borehole and to pass a bulk cement grout through the hose while slowly withdrawing the hose. This method can be used with the roof bolting apparatus disclosed :in US-A-4351625.
Although there are several known method of anchoring a roof bolt, there is still a need for a method and a device by which a simple and non-expensive roof bolt can be reliably anchored at a low cost. In particular, it is desirable that it be possible to anchor the bolt directly in connection wi-th the drilling of the borehole. This invention provides such a method and such a device.
The invention provides a method of roof bolting in which a borehole is drilled in the rock, a batch of bulk grout is intro-duced into the borehole, and an anchor rod is forced into -the ~tP
_J - :
~3~
- la -borehole, characterized in that the batch of grout is ejected from a nozzle at such a speed that i-t forms a jet that reaches the bottom of the borehole.
From another aspect, the invention provides a device for introducing a grout in a borehole comprising a storage means for bulk grout, a conduit for conveying the grout from the stor-age means to the borehole, and means for forcing the grout through said conduit, characterized in that a nozzle is arranged at the end of said conduit and said means for forcing the grout through the conduit comprises a positive displacement pump arranged to exert such a high pressure on the grout that the grout is ejected as a jet from the nozzle.
The invention will further be described with reference to the accornpanying drawings.
Figure 1 is a side view of a mobile rock bolting rig according to the invention.
Figure 2 is a top elevational view of the rig shown in Figure 1.
Figuxe 3 is an enlarged fragmentary view seen as indicat-ed by the arrows 3-3 in Figure 1.
Figure 4 is a side view oE some details shown in Figures 1 and 2.
Figure 5 shows a rock bolt that can be set by means of the rig.
lz36~a The rock bolting rig shown on the drawings comprises a wheeled chass,s 12 on which a boom 13 is swingably mounted. The boom 13 carries pivotably a feed beam 14. A slide 15 is mounted on the feed beam 14 and it can be moved along the feed beam by means of a non-illustrated hydraulic feeding device in a conventional way.
A machine shifting device 16 is mounted on the rear end of the feed beam 14. When the slide 15 is in its rearmost position as shown in Fig 3, a rock drill 17 which is shown in its operational position on the slide 15 can be moved off the slide 15 to the left in the figure and a bolt setter 29 can replace it on the slide 15. This lateral shifting is effected by means of a hydraulic cylinder 18. The bolt setter may include a hydraulic motor so that it can rotate the bolt while forcing it into the borehole. At the front end of the feed beam 14, a support 19 is mounted to pivot about an axis that is parallel with the feed beam. The support 19 carries a guide 20 for a drill steel 21, a nozzle 22, and a guide 23 for a rock bolt 24 of the kind shown in Fig 7. A magazine for rock bolts is indicated in Figs 1 and 2 by reference numeral 43. The bolt 24 or anchoring rod comprises a re-bar 53, a washer or plate 54, and a nut 55. By means of a hydraulic cylinder 25, the drill steel guide 20, which is shown in its operational position, can be swung aside and the nozzle 22 and the guide 23 for the rock bolt can be alternatively swung into their operational positions in line with a borehole 26 drilled by the rock drill 17 and its drill steel 21. The very front of the feed beam 14 comprises a support pad 27 of hard rubber that is arranged to be forced to take support against the rock.
A hose 28 couples the nozzle 22 to a cement grout supplying device 30 that is mounted on the chassis 12.
The cement grout supplying device 30 comprises a frame 31 mounted on the chassis 12. The frame 31 includes a plate 32 and guides 33 for guiding a slide or shutter 34 on the plate ~2. The shutter 3~
carries a cement mixer 35 with a conical housing 36 and a rotatable agitatrr 37 that is driven by a hycraulic motor 38 on Q cover 42 of ~L~3~ 7 the housing 36. The housing 36 forms a mixing chamber which is also a storage chamber;
The bottom end of the conical housing 36 is coaxial with a hole 39 in the shutter 34. The agitator 37 is journalled in a spider 40 mounted in the hole 39. The hose 28 is coupled to a hole 41 in Lhe shutter 34.
A cylinder 45 is suspended in a yoke 46 which is suspended in two bolts 47, 48. Two short hydraulic jacks 49, 50 are arranged as spacers between the yoke 46 and the nuts 51, 52 on the bolts 47, 48.
The jacks 49, 50 are coupled to constantly bias the end face of the cylinder 45 against the slide 34 with a force that permits movement of the slide. Then, the Jacks 49,50 can be actuated to clamp the cylinder 45 against the ,hutter at a considerably larger force to provide for a seal that withstands high pressure. Instead of using the jacks 49, 50 for applying the constantly applied force on the cylinder 95, one can couple springs between the frame 31 and the yoke 46 and use the jacks 49, 50 for the clamping only.
A piston 60 is slidable in the cylinder 45. It has an annular piston rod 61 that slides on a piston 62. The piston rod 59 of the piston 62 is fixed to the frame 31. An annular chamber 57 under the piston 60 is washed with water supplied through a supply conduit 58.
A supply passage 63 for hydraulic fluid leads to a cylinder chamber 64 for urging the piston 60 upwardly in a work stroke and a supply passage ~5 leads to a cylinder chamber 66 for urging the piston 60 downwardly in a return stroke.
A hydraulic cylinder 69 is coupled between the frame 31 and the shutter 34 and it is arranged to move the shutter 34 between three fixed positions. In the right end position of the shutter 34 illustrated in Fig 4, the cernent mixer 35 is coaxial ~Yitll the cylinier 45. In an intermediate position, the hrle 4; is coaxlal ~36~8 with the cylinder 45. In the left end position of the shutter, the conical housing 36 of the mixer 35 is open to a hole 57 in the plate 32. A hose 68 leads from the hole 67 to the ground.
A bolt setting operation Jill now be described.
Before drilling the first hole in a shift or after a break, the cement grout is prepared in the mixer 35. Usually a grout comprisiny only a hydraulic cement e.g., portland cement, and water is used, sometimes a cement mortar with fine sand is used. The shutter 34 is first moved to its intermediate position in which the hole 41 is coaxial with the cylinder and the shutter 32 forms a bottom of the cement mixer 35, and the mixer 35 is filled with dry cement or dry cement mortar and a predetermined amount of water is added. The hydraulic motor 38 is started so that the agitator 37 makes a grout out of the cement and water. The shutter 34 is moved to its position in Fig 4 so that the grout fills the cylinder 45 when, from its uppermost position, the piston 60 is moved downwardly by hydraulic oil supplied to the chamber 66 through the passage 65. The length of the downward return stroke can be adjusted by means of an axially adjustable sensor indicated at 70 so that the effective cylinder volume of the positive displacement pump 45, 60 can be pre-determined and a a pre-determined amount of grout be supplied to the cylinder 45. The shutter 34 is again moved to the left in Fig 4 so that it forms a cylinder head provided with an outlet 41. Then, the piston 60 is actuated by hydraulic oil supplied to the chamber 64 through the passage 65 to perform an upward work strcke, that is, to force the grout in the cylinder 45 out into the hose 28. The pressure in the cylinder 45 can for example be 10 Mpa and the pressure in the nozzle 22 may then be 1 Mpa. The jacks 49, 50 are actuated to clamp the cylinder 45 against the shutter 34 at the same time as the cylinder chamber 66 is pressurized so that a good seal is provided between the cylinder 45 and the shutter 34. The operation is repeated until the hose 28 is filled with grout so that grout is ejected from the nozzle when the piston 5 performs a work stroke.
~3~
_5_ 23805-341 The bolting opera-tion can now s-tart. Thus, -the -feed beam 14 is positioned and forced against the rock, and the rock drill 17 is actuated to drill a hole in the rock. During the drilling operation, the cylinder 45 is Eilled with grout and the shut-ter 34 is moved to its intermediate position in which it forms a head of the cylinder 45 as described above. When the hole has been drilled, the hydraulic cylinder 25 is actuated to position the nozzle 22 in line with the borehole 26. The nozzle 22 is then at the mouth of the borehole. It is adjacent the mouth but at a distance from the mouth as can be seen in Fig 4. It can for example be a few centimeters from the borehole mouth or a few decimeters from it. Then the piston 60 is actuated to force its predetermined volume of grout out into the hose 28 so that a corresponding amount of grout is ejected out of the nozzle 22 as a jet that reaches the botton of the hole. The diameter of the nozzle should be smoothly reduced as shown in Fig 4 in order to provide for a jet and no-t a spray. The outline diameter oE
the nozzle should be less than half the diameter of the borehole or less -than one third -thereof. As an example, the borehole can have a diame-ter of 40 mm, the anchor rod a diameter of 30 mm and the nozzle an outlet diameter of 8 mm. The amount of grout ejected should not completely fill the hole. It should be calculated to fill the space between the bol-t and the borehole when the bolt has been inserted. Thus, the volume of the batch of grout ejected will usually be about half the volume of the borehole. Preferably, the cylinder 45 and the piston 60 are 6~3'7 so designed as to provide a sufficient volume of grout in a borehole in one shot. It is, however, also possible to make them smaller and to shoot more than once. Usually, the operator adds dry cement and water to the housing 36 when the magazine 43 for bolts is empty. Then, the grou-t will be ready to use when he has refilled the magazine 43.
It is usually unavoidable that the jet touch the borehole wall before reaching the bottom of the hole. However, it has been found that the jet fills the borehole from the bo-ttom it its velocity when ejected is higher than about 4 m/s. Thus, its velocity should be at least 6 m/s and preferably it should be between 8 and 15 m/s.
When the batch of grout has thus been delivered to the borehole, the bolt setting machine is actuated -to force a bolt 24 into the borehole until the plate 54 of the bol-t contacts -the rock. When the grout has set, the nut 55 of the bolt can be tightened.
It is a risk tha-t leaking cement will harden on the equipment and make the equipmen-t inoperable. Since a hydraulic cement is used, this problem can be overcome simply by spraying water on vital parts continuously or at short intervels during operation. To this end there are several spray nozzles moun-ted on the rig. Some vital nozzles are marked out on the drawings.
There is a nozzle 72 for spraying on the support 19 and its guides 20, 23 and on the injection nozzle 22. This spray will also wet the bolts when -the bolts are being inserted. Of course, when ~3~9~
-6a- 23805-341 shootiny a jet of grout through the nozzle 22, the spray should be off. Two spray nozzles 73, 74 are moun-ted -to spray on the shu-tter 34 and a spray nozzle 75 is arranged to spray into the housing 36 when the cover 42 thereof is opened. When the operation is interrupted for a longer period, the housing 36 can be cleaned when theshutter 34 is in its left end position in which the housing 36 is open to the drain off hose 68. Then, when the cleaned housing is moved back into its position of Fig 4, water can be furnished to the housing 36 and the piston 60 can be reciprocated to clean the cylinder 45.
In the above description of the preferred embodiment of the invention, elements that are not vi-tal for the understanding of the invention has not been described in detail. The magazine 42 and i-ts 3~9~
operation for example have not been described in detail. The . operation of the shutter 34, the piston 60, and the jacks 49, 50 is preferably carried out automatically as well as the indexing of the support 19 and the exchange of machines on the slide 15.
This invention relates to a method of rock bolting in which a hole is drilled in the rock, a batch of bulk yrout is introduced into the borehole and an anchor rod is forced into the borehole. The invention relates also to a device for carrying out the introduction of grout in the borehole and to a roof bolting apparatus.
In US-A-4158520, a roof bolting apparatus is shown which comprises a rock drill, a bolt setting machine, and a loading device for two-component resin cartridges. The resin cartridges are blown into the borehole and their contents are mixed by the bolt to a hardening mass. In G~-A-953056, cartridges for roof bolting are described which contain a dry cement mortar and a separate compartment of water. It is also known to insert a hose to the bottom of the borehole and to pass a bulk cement grout through the hose while slowly withdrawing the hose. This method can be used with the roof bolting apparatus disclosed :in US-A-4351625.
Although there are several known method of anchoring a roof bolt, there is still a need for a method and a device by which a simple and non-expensive roof bolt can be reliably anchored at a low cost. In particular, it is desirable that it be possible to anchor the bolt directly in connection wi-th the drilling of the borehole. This invention provides such a method and such a device.
The invention provides a method of roof bolting in which a borehole is drilled in the rock, a batch of bulk grout is intro-duced into the borehole, and an anchor rod is forced into -the ~tP
_J - :
~3~
- la -borehole, characterized in that the batch of grout is ejected from a nozzle at such a speed that i-t forms a jet that reaches the bottom of the borehole.
From another aspect, the invention provides a device for introducing a grout in a borehole comprising a storage means for bulk grout, a conduit for conveying the grout from the stor-age means to the borehole, and means for forcing the grout through said conduit, characterized in that a nozzle is arranged at the end of said conduit and said means for forcing the grout through the conduit comprises a positive displacement pump arranged to exert such a high pressure on the grout that the grout is ejected as a jet from the nozzle.
The invention will further be described with reference to the accornpanying drawings.
Figure 1 is a side view of a mobile rock bolting rig according to the invention.
Figure 2 is a top elevational view of the rig shown in Figure 1.
Figuxe 3 is an enlarged fragmentary view seen as indicat-ed by the arrows 3-3 in Figure 1.
Figure 4 is a side view oE some details shown in Figures 1 and 2.
Figure 5 shows a rock bolt that can be set by means of the rig.
lz36~a The rock bolting rig shown on the drawings comprises a wheeled chass,s 12 on which a boom 13 is swingably mounted. The boom 13 carries pivotably a feed beam 14. A slide 15 is mounted on the feed beam 14 and it can be moved along the feed beam by means of a non-illustrated hydraulic feeding device in a conventional way.
A machine shifting device 16 is mounted on the rear end of the feed beam 14. When the slide 15 is in its rearmost position as shown in Fig 3, a rock drill 17 which is shown in its operational position on the slide 15 can be moved off the slide 15 to the left in the figure and a bolt setter 29 can replace it on the slide 15. This lateral shifting is effected by means of a hydraulic cylinder 18. The bolt setter may include a hydraulic motor so that it can rotate the bolt while forcing it into the borehole. At the front end of the feed beam 14, a support 19 is mounted to pivot about an axis that is parallel with the feed beam. The support 19 carries a guide 20 for a drill steel 21, a nozzle 22, and a guide 23 for a rock bolt 24 of the kind shown in Fig 7. A magazine for rock bolts is indicated in Figs 1 and 2 by reference numeral 43. The bolt 24 or anchoring rod comprises a re-bar 53, a washer or plate 54, and a nut 55. By means of a hydraulic cylinder 25, the drill steel guide 20, which is shown in its operational position, can be swung aside and the nozzle 22 and the guide 23 for the rock bolt can be alternatively swung into their operational positions in line with a borehole 26 drilled by the rock drill 17 and its drill steel 21. The very front of the feed beam 14 comprises a support pad 27 of hard rubber that is arranged to be forced to take support against the rock.
A hose 28 couples the nozzle 22 to a cement grout supplying device 30 that is mounted on the chassis 12.
The cement grout supplying device 30 comprises a frame 31 mounted on the chassis 12. The frame 31 includes a plate 32 and guides 33 for guiding a slide or shutter 34 on the plate ~2. The shutter 3~
carries a cement mixer 35 with a conical housing 36 and a rotatable agitatrr 37 that is driven by a hycraulic motor 38 on Q cover 42 of ~L~3~ 7 the housing 36. The housing 36 forms a mixing chamber which is also a storage chamber;
The bottom end of the conical housing 36 is coaxial with a hole 39 in the shutter 34. The agitator 37 is journalled in a spider 40 mounted in the hole 39. The hose 28 is coupled to a hole 41 in Lhe shutter 34.
A cylinder 45 is suspended in a yoke 46 which is suspended in two bolts 47, 48. Two short hydraulic jacks 49, 50 are arranged as spacers between the yoke 46 and the nuts 51, 52 on the bolts 47, 48.
The jacks 49, 50 are coupled to constantly bias the end face of the cylinder 45 against the slide 34 with a force that permits movement of the slide. Then, the Jacks 49,50 can be actuated to clamp the cylinder 45 against the ,hutter at a considerably larger force to provide for a seal that withstands high pressure. Instead of using the jacks 49, 50 for applying the constantly applied force on the cylinder 95, one can couple springs between the frame 31 and the yoke 46 and use the jacks 49, 50 for the clamping only.
A piston 60 is slidable in the cylinder 45. It has an annular piston rod 61 that slides on a piston 62. The piston rod 59 of the piston 62 is fixed to the frame 31. An annular chamber 57 under the piston 60 is washed with water supplied through a supply conduit 58.
A supply passage 63 for hydraulic fluid leads to a cylinder chamber 64 for urging the piston 60 upwardly in a work stroke and a supply passage ~5 leads to a cylinder chamber 66 for urging the piston 60 downwardly in a return stroke.
A hydraulic cylinder 69 is coupled between the frame 31 and the shutter 34 and it is arranged to move the shutter 34 between three fixed positions. In the right end position of the shutter 34 illustrated in Fig 4, the cernent mixer 35 is coaxial ~Yitll the cylinier 45. In an intermediate position, the hrle 4; is coaxlal ~36~8 with the cylinder 45. In the left end position of the shutter, the conical housing 36 of the mixer 35 is open to a hole 57 in the plate 32. A hose 68 leads from the hole 67 to the ground.
A bolt setting operation Jill now be described.
Before drilling the first hole in a shift or after a break, the cement grout is prepared in the mixer 35. Usually a grout comprisiny only a hydraulic cement e.g., portland cement, and water is used, sometimes a cement mortar with fine sand is used. The shutter 34 is first moved to its intermediate position in which the hole 41 is coaxial with the cylinder and the shutter 32 forms a bottom of the cement mixer 35, and the mixer 35 is filled with dry cement or dry cement mortar and a predetermined amount of water is added. The hydraulic motor 38 is started so that the agitator 37 makes a grout out of the cement and water. The shutter 34 is moved to its position in Fig 4 so that the grout fills the cylinder 45 when, from its uppermost position, the piston 60 is moved downwardly by hydraulic oil supplied to the chamber 66 through the passage 65. The length of the downward return stroke can be adjusted by means of an axially adjustable sensor indicated at 70 so that the effective cylinder volume of the positive displacement pump 45, 60 can be pre-determined and a a pre-determined amount of grout be supplied to the cylinder 45. The shutter 34 is again moved to the left in Fig 4 so that it forms a cylinder head provided with an outlet 41. Then, the piston 60 is actuated by hydraulic oil supplied to the chamber 64 through the passage 65 to perform an upward work strcke, that is, to force the grout in the cylinder 45 out into the hose 28. The pressure in the cylinder 45 can for example be 10 Mpa and the pressure in the nozzle 22 may then be 1 Mpa. The jacks 49, 50 are actuated to clamp the cylinder 45 against the shutter 34 at the same time as the cylinder chamber 66 is pressurized so that a good seal is provided between the cylinder 45 and the shutter 34. The operation is repeated until the hose 28 is filled with grout so that grout is ejected from the nozzle when the piston 5 performs a work stroke.
~3~
_5_ 23805-341 The bolting opera-tion can now s-tart. Thus, -the -feed beam 14 is positioned and forced against the rock, and the rock drill 17 is actuated to drill a hole in the rock. During the drilling operation, the cylinder 45 is Eilled with grout and the shut-ter 34 is moved to its intermediate position in which it forms a head of the cylinder 45 as described above. When the hole has been drilled, the hydraulic cylinder 25 is actuated to position the nozzle 22 in line with the borehole 26. The nozzle 22 is then at the mouth of the borehole. It is adjacent the mouth but at a distance from the mouth as can be seen in Fig 4. It can for example be a few centimeters from the borehole mouth or a few decimeters from it. Then the piston 60 is actuated to force its predetermined volume of grout out into the hose 28 so that a corresponding amount of grout is ejected out of the nozzle 22 as a jet that reaches the botton of the hole. The diameter of the nozzle should be smoothly reduced as shown in Fig 4 in order to provide for a jet and no-t a spray. The outline diameter oE
the nozzle should be less than half the diameter of the borehole or less -than one third -thereof. As an example, the borehole can have a diame-ter of 40 mm, the anchor rod a diameter of 30 mm and the nozzle an outlet diameter of 8 mm. The amount of grout ejected should not completely fill the hole. It should be calculated to fill the space between the bol-t and the borehole when the bolt has been inserted. Thus, the volume of the batch of grout ejected will usually be about half the volume of the borehole. Preferably, the cylinder 45 and the piston 60 are 6~3'7 so designed as to provide a sufficient volume of grout in a borehole in one shot. It is, however, also possible to make them smaller and to shoot more than once. Usually, the operator adds dry cement and water to the housing 36 when the magazine 43 for bolts is empty. Then, the grou-t will be ready to use when he has refilled the magazine 43.
It is usually unavoidable that the jet touch the borehole wall before reaching the bottom of the hole. However, it has been found that the jet fills the borehole from the bo-ttom it its velocity when ejected is higher than about 4 m/s. Thus, its velocity should be at least 6 m/s and preferably it should be between 8 and 15 m/s.
When the batch of grout has thus been delivered to the borehole, the bolt setting machine is actuated -to force a bolt 24 into the borehole until the plate 54 of the bol-t contacts -the rock. When the grout has set, the nut 55 of the bolt can be tightened.
It is a risk tha-t leaking cement will harden on the equipment and make the equipmen-t inoperable. Since a hydraulic cement is used, this problem can be overcome simply by spraying water on vital parts continuously or at short intervels during operation. To this end there are several spray nozzles moun-ted on the rig. Some vital nozzles are marked out on the drawings.
There is a nozzle 72 for spraying on the support 19 and its guides 20, 23 and on the injection nozzle 22. This spray will also wet the bolts when -the bolts are being inserted. Of course, when ~3~9~
-6a- 23805-341 shootiny a jet of grout through the nozzle 22, the spray should be off. Two spray nozzles 73, 74 are moun-ted -to spray on the shu-tter 34 and a spray nozzle 75 is arranged to spray into the housing 36 when the cover 42 thereof is opened. When the operation is interrupted for a longer period, the housing 36 can be cleaned when theshutter 34 is in its left end position in which the housing 36 is open to the drain off hose 68. Then, when the cleaned housing is moved back into its position of Fig 4, water can be furnished to the housing 36 and the piston 60 can be reciprocated to clean the cylinder 45.
In the above description of the preferred embodiment of the invention, elements that are not vi-tal for the understanding of the invention has not been described in detail. The magazine 42 and i-ts 3~9~
operation for example have not been described in detail. The . operation of the shutter 34, the piston 60, and the jacks 49, 50 is preferably carried out automatically as well as the indexing of the support 19 and the exchange of machines on the slide 15.
Claims (19)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of roof bolting in which a borehole is drilled in the rock, a batch of bulk grout is introduced into the borehole, and an anchor rod is forced into the borehole, characterized in that the batch of grout is ejected from a nozzle at such a speed that it forms a jet that reaches the bottom of the borehole.
2. A method according to claim 1, characterized in that the nozzle is held at the mouth of the borehole when the grout is ejected.
3. A method according to claim 2, characterized in that the nozzle is held outside the borehole when the grout is ejected.
4. A method according to claim 1, characterized in that the width of the jet as ejected is less than half the width of the borehole.
5. A method according to claim 4, characterized in that the width of the jet as ejected is less than one third of the width of the borehole.
6. A method according to claim 1, characterized in that a predetermined amount of grout is forced into a grout filled con-duit coupled to said nozzle so that a corresponding amount is ejected out of said nozzle as said batch of grout.
7. A method according to claim 6, characterized in that the grout is both metered and forced into the conduit by means of a positive displacement pump.
8. A method according to claim 7, characterized in that a pump with a reciprocable piston is used, and the effective cylinder volume of the pump is used to meter the grout.
9. A method according to claim 1, 2 or 3, characterized in that the jet is ejected out of the nozzle at a velocity of at least 4 m/s.
10. A method according to claim 1, 2 or 3, characterized in that the jet is ejected out of the nozzle at a velocity of at least 6 m/s.
11. A method according to claim 1, 2 or 3, characterized in that water is flushed on the anchor rod while the anchor rod is being forced into the borehole.
12. A method according to claim 1, 2 or 3, characterized in that a grout comprising a hydraulic cement is used.
13. A method of roof bolting in which a hole is drilled in the rock, a batch of bulk grout is introduced into the borehole, and an anchor rod is forced into the borehole, characterized in that the batch of grout is ejected from a nozzle that is position-ed outside the borehole.
14. A device for introducing a grout in a borehole compris-ing a storage means for bulk grout, a conduit for conveying the grout from the storage means to the borehole, and means for forcing the grout through said conduit, characterized in that a nozzle is arranged at the end of said conduit and said means for forcing the grout through the conduit comprises a positive dis-placement pump arranged to exert such a high pressure on the grout that the grout is ejected as a jet from the nozzle.
15. A device according to claim 14, characterized in that said pump comprises a substantially vertical cylinder with a reciprocable piston and means are arranged to alternatively posi-tion a first cylinder head provided with an outlet to said conduit and a second cylinder head provided with a grout supply passage into operative positions on the cylinder.
16. A device according to claim 15, characterized in that said first and second cylinder heads are laterally slidable con-jointly and said storage means is mounted on said second cylinder head.
17. A roof bolting apparatus comprising a chassis, a boom swingably mounted on the chassis, an assembly pivotably mounted on the distal end of the boom and comprising a rock drill, means for introducing a grout in the borehole and a bolt setter, said rock drill, said means, and said bolt setter being sequentially movable into their operating positions on the assembly, character-ized in that said means for introducing the grout in the borehole comprises a nozzle which has its operational position at the mouth of a borehole drilled by the rock drill and is coupled to a posi-tive displacement pump mounted on the chassis, and in that a grout storage means is mounted on the chassis and arranged to feed the pump said pump being arranged to exert such a high pressure on the grout that the grout is ejected as a jet from the nozzle.
18. A roof bolting apparatus according to claim 17, character-ized in that said storage means comprises a cement grout mixer.
19. A roof bolting apparatus according to claim 17 or 18, characterized by means for spraying water on said assembly.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000455419A CA1236987A (en) | 1984-05-30 | 1984-05-30 | Method of rock bolting, and a device, and a roof bolting apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000455419A CA1236987A (en) | 1984-05-30 | 1984-05-30 | Method of rock bolting, and a device, and a roof bolting apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1236987A true CA1236987A (en) | 1988-05-24 |
Family
ID=4127966
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000455419A Expired CA1236987A (en) | 1984-05-30 | 1984-05-30 | Method of rock bolting, and a device, and a roof bolting apparatus |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1236987A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014035316A1 (en) * | 2012-08-30 | 2014-03-06 | Atlas Copco Rock Drills Ab | Method, device and vehicle for rock bolt setting as well as computer program product |
| WO2018231117A1 (en) * | 2017-06-14 | 2018-12-20 | Epiroc Rock Drills Aktiebolag | Arrangement and method at rock reinforcement |
-
1984
- 1984-05-30 CA CA000455419A patent/CA1236987A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014035316A1 (en) * | 2012-08-30 | 2014-03-06 | Atlas Copco Rock Drills Ab | Method, device and vehicle for rock bolt setting as well as computer program product |
| WO2018231117A1 (en) * | 2017-06-14 | 2018-12-20 | Epiroc Rock Drills Aktiebolag | Arrangement and method at rock reinforcement |
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