CA1106234A - Tamping cartridge - Google Patents
Tamping cartridgeInfo
- Publication number
- CA1106234A CA1106234A CA307,451A CA307451A CA1106234A CA 1106234 A CA1106234 A CA 1106234A CA 307451 A CA307451 A CA 307451A CA 1106234 A CA1106234 A CA 1106234A
- Authority
- CA
- Canada
- Prior art keywords
- cartridge
- tampable
- overlap
- unsealed
- areas
- 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
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
- F42B3/00—Blasting cartridges, i.e. case and explosive
- F42B3/087—Flexible or deformable blasting cartridges, e.g. bags or hoses for slurries
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Impact Printers (AREA)
- Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)
- Metal Extraction Processes (AREA)
- Drilling And Exploitation, And Mining Machines And Methods (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Tampable cartridge A closed tubular sheath, which contains a blasting explosive composition, wherein the wrapped material of the sheath has unsealed areas of overlap When tamped in a borehole, the pressure on the cartridge causes it to deform to a shorter length and greater width so as to expand and fill the cross section or bore of the hole without exposing the composition.
Tampable cartridge A closed tubular sheath, which contains a blasting explosive composition, wherein the wrapped material of the sheath has unsealed areas of overlap When tamped in a borehole, the pressure on the cartridge causes it to deform to a shorter length and greater width so as to expand and fill the cross section or bore of the hole without exposing the composition.
Description
11~6Z3~
This invention relates to tampable blasting cartridges In the past it had been traditional for explosives intended for use as blasting explosives in boreholes or shotholes to be prepared as cartridges of conventional dynamite, which were packed in paper of various qualities. These cartridges were manufactured usually by spirally winding thick paper, often impregnated with wax, into a hollow cylinder. The explosive was retained in the cylinder by a closure at each of its op-10 posite ends, the typical closure being known as a "crimp"The method of crimping essentially was a folding over and ra-dially inwardly of the paper wall of the open end of the cylinder and pressing the folded over paper against the explo-sive Such cartridges were rigid tubes of predetermined 15 diameter.
The advent of synthetic resin plastics as a commodity of commerce soon provided another material for packaging explosives and rigid tubes of plastics with a type of plug or cap at each end made their appearance. More commonly, 20 however, the modern types of explosive compositions such as the ammonium nitrate/fuel oil blasting agents and the aqueous slurry or water based gel explosives have been packed in plastics bags or cylinders made of tubular plastics film with closures at each end. The cylinder is available either as 25 a preformed, flattened tube, which is filled from one end, or is made by continuously forming a tube from a flat length of plastics film, which is folded over to a circular form and welded or otherwise sealed by adhesive down the longitudinal seam Such a continuously formed tube is filled, sealed 30 transversely at specified unit lengths of tubing and ~ .
-cut through adjacent the seal to provide the so-called sausage of blasting explosive. Normally the transverse sealing is effected by a loop or ring of metal, which is bent and thus fastened around the constricted plastics tube after completion of the filling operation.
- In blasting operations it is of prime importance that the blasting explosives totally fill the cross-section of the drilled cavity at the place where it will be initiated to ensure the maximum effect of shock waves penetrating the surrounding rock. The explosive charge may not perform its designed task if cushioned by pockets of air or allowed to expend itself uselessly in any direction.
In most blasting applications, for instance, the slurry type of explosives needs to be well tamped in holes of small diameter.
Present practice to achieve this objective with known packaged explosives fails for several reasons. If sausages of explosives are forcibly compressed or tamped, the plastics film invariably ruptures and the sausages burst open. It is known that plastics films widely used for packaging ~ explosives have high tensile strength until a tear is initiated and that the tear propagates eas1y. It is also known that sausages made of a plastics film, which does not propagate a tear easily, do not tamp efficiently. It is known further that the properties of the explosives will be affected adversely when in contact with water in a wet borehole. The practical disadvantage of having to prevent water from mixing with the explosive ~-composition when tamping it in the toe of a borehole is a serious and difficult one.
23~
Attempts to overcome the problem by increasing the diameter of the sausage to approximate as nearly as is possible to that of a borehole are unsuccessful, The sausages either become wedged some distance down the hole due to the irregularities in the wall of the hole and then burst when forcibly urged further on or.
the film of the sausages snags on projections in the wall and the sausages expose or expel their contents, In the sequential blasting of a large number of boreholes, the failure of one or more blasting agents to explode presents the underground miner or the quarry operator with a hazardous and time wasting task, The unblasted holes have to be cleaned out, 15 recharged and blasted, Routine work is interrupted and mine production delayed, The object of this invention is to provide packaging for explosives compositions to eliminate or minimise the disadvantages inherent in known packaging 20 for use in loading and blasting boreholes, According to this invention a tamping cartridge suitable for use in a borehole comprises a blasting explosive composition sheathed in a tubular covering of moisture impervious material sealed at its opposite ends 25 and including deforming means, which enable the cartridge to expand across its width when tamped in the borehole without rupturing the material and thereby exposing the composition, An embodiment of the invention is a tampable blasting 30 cartridge wherein the covering is an inner tube, the material of which has an area of overlap in unsealed contact along its lengitudinal edges, and an outer tube such that the inner tube fits intimately within :
11~6~3~
the outer tube of spirally wrapped material with areas of overlap in unsealed contact at the edges of the material, the deforming means comprising said areas of overlap of material in unsealed contact Another embodiment is a tampable blasting cartridge wherein the covering is an inner tube of spirally wrapped material with areas of overlap in unsealed contact at the edges of the material and an outer tube such that the inner 10 tube fits intimately within the outer tube of spirally counterwrapped material with areas of overlap in unsealed contact at the edges of the material, the deforming means comprising said areas of overlap of material in unsealed contact Tamping cartridges of this invention may be designed to have preferential parts of expansion, depending on the particular requirements of its application Thus any one or more parts of a cartridge may have overlapping areas of material in unsealed contact along the borders or edges 20 of the material in specific locations of the cartridge where expansion is required. The material may be, for example, waxed paper, thermoplastics coated paper, thermo-plastics film and latex rubber A combination of any two or more different materials may be desirable in a tamping 25 cartridge of the invention. The opposite ends of the cartridge will be sealed in known manner by glueing, hot-air or hot-melt welding or by metal clip, for example While the tamping cartridge is adaptable to blasting with any type of explosive composition 30 normally used for blasting purposes in boreholes, it is especially suited to the packaging of water based gel explosives and other similar explosive slurries The invention provides a package for blasting agents and a final product which combines economy of production ~'~
.
6~234-and use with safety, convenience and explosive effective-ness under unfavourable conditions, The tampable cartridge of the invention may be packed and supplied in case lots but it is a product adapted to being provided also in a detachable train form, Such a configuration permits the operator to choose any number of cartridges as may suit the needs of the blasting operation to be undertaken, The connected 10 cartridges for multiple use can be simply pleated together in accordian fashion to provide longer blasting charges, Single cartridges may be detached by tearing along a perforated or otherwise weakened web between two sealed ends of adjoining cartridges, One embodiment of the invention will be described by way of example with reference to the accompanying drawings in which Figure l shows a view of a tampable cartridge to illustrate its construction, and Figure 2 shows a view of the completed cartridge of Figure l but after it has been tamped.
Referring to the drawings in which like numerals designated like parts, the tampable cartridge shown in Figure 1 has an inner tube 10 of low density polyethylene 25 which fits snugly within an outer tube ll of low density polyethylene, The inner tube lO has an area of an over-lap along its longitudinal edges as is indicated by numeral 12. The overlap is unsealed and the material is allowed free movement as between the upper and lower layers in 30 contact but subject to the restrictions impased by the mass of explosive composition filling the inner tube lO
and by the outer tube ll, The outer tube ll has been wrapped spirally around the inner tube lO so that the material along '~
11~6~3~
its edges overlap as is indicated by numeral 13.
These overlaps also are unsealed and the material is allowed free movement as between the upper and lower layers in contact but subject to the restrictions imposed by the tightness of the wrapping upon the inner tube 10 and the pressure exerted radially outwards by the mass of explosive in tube 10, One end of the two tubes 10 and 11 has been sealed 10 by a metal clip 14 but the opposite end 15 has not been completed and sealed so as to reveal its features, After completion of filling tube 10 with explosives, the opposite end 15 will be wrapped and sealed with a metal clip 14 as is illustrated at the lower end of 15 Figure 1 to form a tamping cartridge, In use in the field, a tampable cartridge as exemplified above would be inserted into a borehole and tamped home. The cartridge would expand during tamping so as to become shorter in length and wider in 20 diameter as illustrated in Figure 2. In the form shown in the drawing, the tamping operation has compressed the explosive mass, which is in a plastic state, so as to widen the cartridge transversely to form a good seal with the periphery of the hole but 25 without any rupture in the covering material which would expose the explosive composition to moisture, It will be obvious to those skilled in the art that various embodiments of the tampable cartridge of this invention falling within the scope of the 30 accompanying claims may be suitably employed in the exercise of this invention, .~ ,~ .
'
This invention relates to tampable blasting cartridges In the past it had been traditional for explosives intended for use as blasting explosives in boreholes or shotholes to be prepared as cartridges of conventional dynamite, which were packed in paper of various qualities. These cartridges were manufactured usually by spirally winding thick paper, often impregnated with wax, into a hollow cylinder. The explosive was retained in the cylinder by a closure at each of its op-10 posite ends, the typical closure being known as a "crimp"The method of crimping essentially was a folding over and ra-dially inwardly of the paper wall of the open end of the cylinder and pressing the folded over paper against the explo-sive Such cartridges were rigid tubes of predetermined 15 diameter.
The advent of synthetic resin plastics as a commodity of commerce soon provided another material for packaging explosives and rigid tubes of plastics with a type of plug or cap at each end made their appearance. More commonly, 20 however, the modern types of explosive compositions such as the ammonium nitrate/fuel oil blasting agents and the aqueous slurry or water based gel explosives have been packed in plastics bags or cylinders made of tubular plastics film with closures at each end. The cylinder is available either as 25 a preformed, flattened tube, which is filled from one end, or is made by continuously forming a tube from a flat length of plastics film, which is folded over to a circular form and welded or otherwise sealed by adhesive down the longitudinal seam Such a continuously formed tube is filled, sealed 30 transversely at specified unit lengths of tubing and ~ .
-cut through adjacent the seal to provide the so-called sausage of blasting explosive. Normally the transverse sealing is effected by a loop or ring of metal, which is bent and thus fastened around the constricted plastics tube after completion of the filling operation.
- In blasting operations it is of prime importance that the blasting explosives totally fill the cross-section of the drilled cavity at the place where it will be initiated to ensure the maximum effect of shock waves penetrating the surrounding rock. The explosive charge may not perform its designed task if cushioned by pockets of air or allowed to expend itself uselessly in any direction.
In most blasting applications, for instance, the slurry type of explosives needs to be well tamped in holes of small diameter.
Present practice to achieve this objective with known packaged explosives fails for several reasons. If sausages of explosives are forcibly compressed or tamped, the plastics film invariably ruptures and the sausages burst open. It is known that plastics films widely used for packaging ~ explosives have high tensile strength until a tear is initiated and that the tear propagates eas1y. It is also known that sausages made of a plastics film, which does not propagate a tear easily, do not tamp efficiently. It is known further that the properties of the explosives will be affected adversely when in contact with water in a wet borehole. The practical disadvantage of having to prevent water from mixing with the explosive ~-composition when tamping it in the toe of a borehole is a serious and difficult one.
23~
Attempts to overcome the problem by increasing the diameter of the sausage to approximate as nearly as is possible to that of a borehole are unsuccessful, The sausages either become wedged some distance down the hole due to the irregularities in the wall of the hole and then burst when forcibly urged further on or.
the film of the sausages snags on projections in the wall and the sausages expose or expel their contents, In the sequential blasting of a large number of boreholes, the failure of one or more blasting agents to explode presents the underground miner or the quarry operator with a hazardous and time wasting task, The unblasted holes have to be cleaned out, 15 recharged and blasted, Routine work is interrupted and mine production delayed, The object of this invention is to provide packaging for explosives compositions to eliminate or minimise the disadvantages inherent in known packaging 20 for use in loading and blasting boreholes, According to this invention a tamping cartridge suitable for use in a borehole comprises a blasting explosive composition sheathed in a tubular covering of moisture impervious material sealed at its opposite ends 25 and including deforming means, which enable the cartridge to expand across its width when tamped in the borehole without rupturing the material and thereby exposing the composition, An embodiment of the invention is a tampable blasting 30 cartridge wherein the covering is an inner tube, the material of which has an area of overlap in unsealed contact along its lengitudinal edges, and an outer tube such that the inner tube fits intimately within :
11~6~3~
the outer tube of spirally wrapped material with areas of overlap in unsealed contact at the edges of the material, the deforming means comprising said areas of overlap of material in unsealed contact Another embodiment is a tampable blasting cartridge wherein the covering is an inner tube of spirally wrapped material with areas of overlap in unsealed contact at the edges of the material and an outer tube such that the inner 10 tube fits intimately within the outer tube of spirally counterwrapped material with areas of overlap in unsealed contact at the edges of the material, the deforming means comprising said areas of overlap of material in unsealed contact Tamping cartridges of this invention may be designed to have preferential parts of expansion, depending on the particular requirements of its application Thus any one or more parts of a cartridge may have overlapping areas of material in unsealed contact along the borders or edges 20 of the material in specific locations of the cartridge where expansion is required. The material may be, for example, waxed paper, thermoplastics coated paper, thermo-plastics film and latex rubber A combination of any two or more different materials may be desirable in a tamping 25 cartridge of the invention. The opposite ends of the cartridge will be sealed in known manner by glueing, hot-air or hot-melt welding or by metal clip, for example While the tamping cartridge is adaptable to blasting with any type of explosive composition 30 normally used for blasting purposes in boreholes, it is especially suited to the packaging of water based gel explosives and other similar explosive slurries The invention provides a package for blasting agents and a final product which combines economy of production ~'~
.
6~234-and use with safety, convenience and explosive effective-ness under unfavourable conditions, The tampable cartridge of the invention may be packed and supplied in case lots but it is a product adapted to being provided also in a detachable train form, Such a configuration permits the operator to choose any number of cartridges as may suit the needs of the blasting operation to be undertaken, The connected 10 cartridges for multiple use can be simply pleated together in accordian fashion to provide longer blasting charges, Single cartridges may be detached by tearing along a perforated or otherwise weakened web between two sealed ends of adjoining cartridges, One embodiment of the invention will be described by way of example with reference to the accompanying drawings in which Figure l shows a view of a tampable cartridge to illustrate its construction, and Figure 2 shows a view of the completed cartridge of Figure l but after it has been tamped.
Referring to the drawings in which like numerals designated like parts, the tampable cartridge shown in Figure 1 has an inner tube 10 of low density polyethylene 25 which fits snugly within an outer tube ll of low density polyethylene, The inner tube lO has an area of an over-lap along its longitudinal edges as is indicated by numeral 12. The overlap is unsealed and the material is allowed free movement as between the upper and lower layers in 30 contact but subject to the restrictions impased by the mass of explosive composition filling the inner tube lO
and by the outer tube ll, The outer tube ll has been wrapped spirally around the inner tube lO so that the material along '~
11~6~3~
its edges overlap as is indicated by numeral 13.
These overlaps also are unsealed and the material is allowed free movement as between the upper and lower layers in contact but subject to the restrictions imposed by the tightness of the wrapping upon the inner tube 10 and the pressure exerted radially outwards by the mass of explosive in tube 10, One end of the two tubes 10 and 11 has been sealed 10 by a metal clip 14 but the opposite end 15 has not been completed and sealed so as to reveal its features, After completion of filling tube 10 with explosives, the opposite end 15 will be wrapped and sealed with a metal clip 14 as is illustrated at the lower end of 15 Figure 1 to form a tamping cartridge, In use in the field, a tampable cartridge as exemplified above would be inserted into a borehole and tamped home. The cartridge would expand during tamping so as to become shorter in length and wider in 20 diameter as illustrated in Figure 2. In the form shown in the drawing, the tamping operation has compressed the explosive mass, which is in a plastic state, so as to widen the cartridge transversely to form a good seal with the periphery of the hole but 25 without any rupture in the covering material which would expose the explosive composition to moisture, It will be obvious to those skilled in the art that various embodiments of the tampable cartridge of this invention falling within the scope of the 30 accompanying claims may be suitably employed in the exercise of this invention, .~ ,~ .
'
Claims (9)
1. A tampable blasting cartridge suitable for use in a borehole comprising a blasting explosive composition sheathed in a tubular covering of moisture impervious material sealed at its opposite ends and including deforming means comprising overlapped wrapper portions in unsealed freely moveable contact whereby the cartridge is enabled to expand across its width when tamped in the borehole without stretching or rupturing any of the said material.
2. A tampable cartridge as claimed in Claim 1 wherein the covering is an inner tube, the material of which has an area of overlap in unsealed contact along its longitudinal edges, and an outer tube of a spirally wrapped material having areas of overlap in unsealed freely moveable contact at the edges of the material the inner tube fitting intimately within the outer tube, the deforming means comprising said areas of overlap of material in un-sealed contact.
3. A tampable cartridge as claimed in Claim 1 wherein the covering is an inner tube of a spirally wrapped material having areas of overlap in unsealed freely moveable contact at the edges of the material and an outer tube of a spirally counterwrapped material having areas of overlap in unsealed freely moveable contact at the edges of the material, the inner tube fitting intimately within the outer tube and the deforming means comprising said areas of overlap of material in unsealed contact.
4. A tampable cartridge as claimed in Claim 1, 2 or 3 wherein the deforming means is located in a part or parts of the said tubular covering material designed to direct a preferred expansion of the cartridge.
5. A tampable cartridge as claimed in Claim 1, 2 or 3 wherein the moisture impervious material is selected from waxed paper, thermoplastics coated paper, thermoplastics film and latex rubber.
6. A tampable cartridge as claimed in Claim 2 or 3 wherein the inner tube is of a material different from the material of the outer tube.
7. A tampable cartridge as claimed in Claim 1, 2 or 3 wherein the blasting explosive comprises a slurry explosive.
8. A tampable cartridge as claimed in Claim 1, 2 or 3 wherein the blasting explosive comprises an ammonium nitrate/
fuel oil explosive.
fuel oil explosive.
9. Tampable cartridges as claimed in Claim 1, 2 or 3 detachably connected together in end-to-end relationship.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ZA77/4217 | 1977-07-14 | ||
| ZA00774217A ZA774217B (en) | 1977-07-14 | 1977-07-14 | Tamping cartridge |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1106234A true CA1106234A (en) | 1981-08-04 |
Family
ID=25571789
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA307,451A Expired CA1106234A (en) | 1977-07-14 | 1978-07-14 | Tamping cartridge |
Country Status (5)
| Country | Link |
|---|---|
| BR (1) | BR7804413A (en) |
| CA (1) | CA1106234A (en) |
| GB (1) | GB2002499B (en) |
| NZ (1) | NZ187769A (en) |
| ZA (1) | ZA774217B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014168495A1 (en) | 2013-04-10 | 2014-10-16 | PRZEDSIĘBIORSTWO PRODUKCYįNO-HANDLOWO-USŁUGOWE | Tamping cartridge for mining |
-
1977
- 1977-07-14 ZA ZA00774217A patent/ZA774217B/en unknown
-
1978
- 1978-06-30 GB GB7828422A patent/GB2002499B/en not_active Expired
- 1978-07-03 NZ NZ187769A patent/NZ187769A/en unknown
- 1978-07-07 BR BR7804413A patent/BR7804413A/en unknown
- 1978-07-14 CA CA307,451A patent/CA1106234A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014168495A1 (en) | 2013-04-10 | 2014-10-16 | PRZEDSIĘBIORSTWO PRODUKCYįNO-HANDLOWO-USŁUGOWE | Tamping cartridge for mining |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2002499A (en) | 1979-02-21 |
| BR7804413A (en) | 1979-03-06 |
| NZ187769A (en) | 1981-03-16 |
| ZA774217B (en) | 1979-02-28 |
| GB2002499B (en) | 1982-01-06 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |