US3645205A - Packaged explosive - Google Patents

Abstract

Packaged explosives of the type known as bombing charges are provided. The packaged explosive is composed of a flexible container filled with a deformable explosive. An apertured plate is positioned in the bottom end of the container for receiving and engaging a pusher pole. When the pusher pole is inserted into the container, through the aperture of the bottom plate, the plate engages the pole so as to keep the package aligned on the pole and prevent the packaged explosive from rotating on the pole while the packaged explosive is being positioned at the blast site.

Description

Dowlin 1 Feb. 29 1972 [54] PACKAGED EXPLOSIVE 2,685,836 8/1954 Sauvage ..102/26 X 3,472,166 10/1969 Dowling ..l02/24 [72] Inventor: Thomas P. Dowling, Fullerton, Pa.

[73] Assignee: Commercial Solvents Corporation, New Primary E i v lin R. Pendegmss York, NY. Attorney-James and Chapman [22] Filed: May 8, 1969 [211 App]. No.: 323,004 [57] ABSTRACT Packaged explosives of the type known as bombing charges Related Applicamm Dam are provided. The packaged explosive is composed of a flexi- [63 Continuatiomimpan of Ser No 704 037 Feb 8 ble container filled with a deformable explosive. An apertured 1968 Pat No 3 472 166 plate is positioned in the bottom end of the container for receiving and engaging a pusher pole. When the pusher pole is [52] Cl 102/24 inserted into the container, through the aperture of the bot- [5 1] Im- CL 3/00 tom p the plate g g the p so as to p the p g [58] Field of'search' 102/24 aligned on the pole and prevent the packaged explosive from rotating on the p while the p g explosive is being 56] References Cited positioned at the blast site.

UNITED STATES PATENTS 18 Claims, 5 Drawing Figures 1,571,122 1/1926 Hutton .....102 /26 PACKAGED EXPLOSIVE This application is a continuation-in-part of application Ser. No. 704,037 filed Feb. 8, 1968, now US. Pat. No. 3,472,166, patented Oct. 14, 1969.

This invention relates to packaged explosives particularly of the type known as bombing charges.

In mining operations and particularly in mining operations such as block caving and sublevel stopping, the ore chute often becomes blocked with large boulders or rock fragments which usually become wedged into position blocking the chute. Such blockages are extremely difficult to remove. l-leretofore, in order to remove such a blockage the practice has been to detonate a bagged explosive charge known as a bombing charge placed adjacent the blockage between the boulder and the chute wall to blast the chute clear. The bombing charge is a pliable or deformable explosive such as a granular explosive, a plastic gel, or a thick slurry in a relatively flexible bag. A long wooden pusher pole is inserted into the package through the rear end of the bag, and the bombing charge is then jammed between the wall and the boulder or rock fragment to be moved. Several such packages are positioned around the boulder to provide a sufficient explosive force to dislodge it.

I One difficulty with this procedure has been that the explosive package tends to rotate on the pole when it is placed in position at the blast site. Because the package rotates on the pole and the explosive is in a flexible nonshape supporting wrapper, there is a tendency for the explosive in a package to move, and change the shape and center of gravity of package when the pusher pole is inserted. The result is that the package tends to sag or turn away from the position in which it is to be placed and the explosive cannot be positioned in the location where it can be most effective. In addition, due to the sagging and rotation of the container, it often happens that the end of the pole pierces or bursts through a wall of the container and penetrates the explosive material which makes it impossible to position the explosive container properly at the blast site. Also, the explosive can leak from the package.

The instant invention provides a packaged explosive particularly suited for use as a bombing charge which can be positioned at the blast site by use of a pusher pole, and is provided with a support plate for holding the package in a fixed position on the pole, so that no rotation of the package relative to the pole can occur. The plate also supports the explosive composition in the package, and engages the poles so as to keep the package aligned with the pole, and thereby minimizes the possibility of the poles piercing the wall of the container. Thus, the packaged explosive provides some resistance to the pole being forced through the side of the package, and at the same time is flexible enough to assume the shape of the space in which it is placed.

in accordance with this invention, a packaged explosive of the category described above is provided, comprising a generally flexible container; a deformable explosive therein; a fuse for detonating the explosive in the container and extending in part therefrom; and a positioning and support plate disposed at the bottom of the container for receiving and engaging a pusher pole in a manner to fix the packaged explosive against rotation relative to the pole and to keep the packaged explosive aligned relative to the pole, to thereby facilitate the placing of the packaged explosive in position at the blast site.

The container for the explosive is a tube or bag made of a generally flexible sheet material. Plastic films made of polypropylene, polyethylene, polyvinyl chloride, polyvinylidene chloride, nylon, polyacrylonitrile, polycaprolactam, polyethylene glycol terephthalate (Mylar), polybutadiene, polyurethanes, natural and synthetic rubbers, polyepoxide resins and the like are preferred. However, kraft paper and fabrics made of cotton, burlap, jute, sisal, hemp and the like are also suitable. Multiply composites of the materials specified above can also be used. The container is preferably relatively liquid impervious when used for explosives containing liquid ingredients, such as water, or liquid sensitizers and oils, to prevent loss through the walls of the container. lf water-pervious materials such as paper and fabrics are used, they can be coated with a hydrophobic coating material such as a silicone resin. The material of the container should also be relatively strong, and abrasion and tear resistant, so that it does not burst or tear when forced into place. The container can be made in any shape, as long as it can accommodate itself to the space limitations normally found at the blast site. The container can comprise a double-walled bag or two bags, one inserted within the other, as is explained below.

The explosive composition used should be deformable or pliable enough to fit, to the extent permitted by the container, into the space between the boulder and the chute when forced into position. The explosive can be in the form of a powder, a granular composition, a soft gel, a plastic gel, a semisolid slurry, or a relatively thick slurry. Thin slurries or liquid explosives of low viscosity can also be used, if precautions are taken to prevent leakage. An embodiment of this invention particularly suited for such explosive compositions is described below. Any high explosive can be used, such as TNT-sensitized ammonium nitrate-type slurried high explosives, smokeless powder-sensitized ammonium nitrate-type slurried high explosives; nitrostarch-sensitized ammonium nitrate-type slurried high explosives; TNT-ammonium nitrate pellet form solid high explosives, and nitrostarch-sensitized ammonium nitrate-type semisolid high explosives, nitrocarbonitrates, and nitroglycerine dynamites, such as semigelatins, ammonia gelatins and ammonia dynamites, of regular or specially desensitized types. Typical explosive composition formulations that are particularly suitable for use in this invention are described hereinafter.

The bottom plate is normally located at the bottom of the container. The plate is preferably a relatively thin flat plate; however, thick plates can also be used. The plate can be of any type of material: metal, wood, or plastic are generally suitable, and sufficiently rigid to support the weight of the contents of the package without substantial distortion. Polystyrene, polyvinyl chloride, polyethylene, polypropylene, and polycarbonate plastics are preferred. Materials such as cardboard, fiberboard, plywood, steel and aluminum also can be used.

When a plastic plate is used, it is quite convenient to fabricate the plate as one piece, which can have either a well or lugs as an integral part thereof for engaging the pole. The bottom plate can take generally any shape, and circular, square, elliptical, rectangular and polygonal shapes are suitable. The shape and size of the support plate, however, should correspond to the approximate dimensions of the bottom of the container so that the plate fits relatively tightly thereagainst. It is preferred that the plate be fixed to the bottom of the container such as by bonding. This can conveniently be done when the container and/or the plate are made of thermoplastic materials simply by heat-bombing the plate to the container wall.

If the plate is bonded to the container, it need not be within it but can be bonded to the exterior bottom of the container. The plate in fact, can be the bottom of the container.

It is also possible to keep the plate in position by placing the explosive in an inner container, and placing the plate in the bottom of an outer container in which the inner container is placed on top of the plate. In this manner, the plate is captured between the two containers, and cannot move relative to the explosive.

By locating the plate at the bottom of the container easy access to the plate from below is assured. Furthermore, by positioning the plate at the bottom of the container, there is no possibility that the explosive can seep around the plate and alter the center of gravity and relative orientation of the container to the pole upon positioning of the packaged explosive at the blast site. This helps ensure that proper alignment of the pole and the package is maintained.

The plate receives and engages the pushing pole so as to prevent rotation of the explosive package on the pole. This can be done in several ways. The preferred way is by providing an aperture which admits the pole but engages a portion of the pole so as to prevent relative rotation of the pole and the packaged explosive. For example, if a pole having a rectangular cross section is used, the plate can have a rectangular aperture which matches the cross-sectional shape of the pole, and is just large enough to permit the tip of the pole to pass through. The aperture then engages the flat sides of the pole tip, and prevents relative rotation of the package and the pole. The aperture need not be rectangular, but can be any shape suited to engage and fix the pole against relative rotation. If a pole with a tapered end is used, the aperture in the plate can be dimensioned so as to fricfionally engage the tapered portion of the pole in a wedgelike manner, so that relative rotation of the package and the pole is prevented.

The plate aperture can be provided with gripping members such as teeth or protrusions located at the periphery of the aperture, dimensioned to engage the pole and grip it.

It has been found convenient to provide a punch-out aperture, by means of a series of perforations or weakened portions in the plate in the shape of the desired aperture. When the pusher pole is forced thereagainst, the perforations or weakened portions will give way, and the pole can then be inserted through the plate. Using this technique it is a simple matter to form teeth or gripping members about the aperture by weakening or perforating the plate in a zigzag or toothlike aperture configuration. Other means for receiving and engaging the pole, such as lugs, guides, clips, clamps, and the like, can also be provided on the plate, to receive and engage the pole to prevent relative rotation of the pole and the packaged explosive, and assist in keeping the pole and packaged explosive in axial alignment. In all instances since the plate fits relatively snugly against the sides of the container, or is bonded to the container, and since the plate engages the pole, the explosive package is fixed on the pole against relative rotation, and in axial alignment with the pole, due to the fact that the aperture acts as a guide to direct the pole in position. If the aperture is only just large enough to permit the tip of the pole to pass through it, the sides of the aperture will engage the sides of the pole, and help ensure that the pole does not pierce the wall of the container. In addition, by maintaining alignment of the package on the pole, the degree to which an imbalance of the explosive with respect the pole can occur is also minimized.

It should be noted that in addition to preventing relative rotation of the pole and the package, the plate can engage the pole in a manner to distribute the force applied by the pole to the walls of the package as described in copending application Ser. No. 704,037 filed Feb. 8, 1968, now US. Pat. No. 3,472,166 granted Oct. 14, 1969. This can also be accomplished if there is a tapered end on the pole. In such a case the aperture can wedge the sides of the tapered end, thereby preventing both rotation of the explosive package on the pole, and also preventing the pole from passing through the plate, so that the plate distributes to the explosive in the container the force applied in forcing the explosive package into position.

As another example, the plate can be provided with a well, adapted to receive the end of the pole and provide a bearing surface for the end of the pole, against which the force required to push the explosive package into position can be exerted. The sides of the well should also be shaped to engage the sides of the pole, to prevent relative rotation of the pole and the explosive package.

It is also possible to provide a flange, lugs or pins on the pusher pole, spaced from the end of the pole, to engage the plate, and prevent the pole from passing too far through the package and piercing the wall of the container. The flange, pins or lugs also aid in keeping the package and pole aligned.

The fuse is preferably a fuse of the Primacord detonating fuse type. However, other fuse cords of both the deflagrating and detonating type are also suitable.

The plate can hold the fuse within the container and also hold at least a portion of the fuse adjacent one end thereof in position in the container, as described in U.S. Pat. No.

3,472,166. However, the fuse need not be attached to the plate. It can be held in position by merely tying a knot in the fuse, running the remainder of the fuse out of the top end of the container package and tying the package top end closed about the fuse, so that the knot on the fuse abuts the tied closed end of the package so as to hold the fuse in the package. If desired a second knot, loop, bail or wad of fuse can be left in the package to provide additional explosive force to initiate the explosive within the container. If desired, the knot, loop, or bail of the fuse cord can be provided with a booster explosive such as TNT, Pentolite, Composition B, or the like, cast or molded into position on the knot. This can be done either by dipping the knot in a molten booster explosive, or by forming the booster in wad about it.

A loop or bail of the fuse can be left outside of the package for easy attachment to a downline fuse.

The explosive can be packaged by first inserting the bottom plate in the bottom of a container, such as a cylinder or bag of a generally flexible material, and then inserting into the container a length of knotted fuse which extends out of the end of the container. The container is then filled with a deformable explosive, and the top end of the container is tied about the fuse. The fuse is drawn up until the knot engages the tied end of the container. Other methods for packaging the explosive depending upon the particular embodiment of the invention desired will be apparent to those skilled in the art.

When the packaged explosive is to be used, the end of the container in which the plate is located is slit. The pusher pole is then inserted through the slit and into the aperture of the plate so that the sides of the pole are engaged by the bottom plate. The downline fuse is attached to the detonating fuse at the other end of the container. The container is then jammed into position. The packaged explosive cannot rotate relative to the pole and therefore the explosive can be readily positioned so as to impart the maximum explosive force wherever desired. The engagement of the plate and the pole helps maintain axial alignment of the packaged explosive and the pole. This aids in keeping the pole from reaching and piercing the wall of the container. The explosive charge is then ready to be detonated.

In the drawings:

FIG. 1 is a view in cross section of a packaged explosive in accordance with this invention,

FIG. 2 is a view taken along the line 22 of FIG. 1,

FIG. 3 is a view similar to that of FIG. 1 of another embodiment of this invention,

FIG. 4 is a view similar to FIG. 1 of a third embodiment of this invention and,

FIG. 5 is a view similar to FIG. 2 of another embodiment of the invention.

In the embodiment shown in FIG. 1, double container 2 is formed of two polyethylene plastic film bags 2a and 2b. The bag 2a encloses the bag 2b and a mass of thixotropic semisolid explosive 3 is enclosed within the bag 2b. The explosive 3 is of the following composition:

Nitrostarch (dry) 39.00 NILNO (grained) 31.25 NANO; (grained) 12.00 ZnO 0.80

Flake Aluminum 1.75 Solium Carboxymethyl cellulose 0.90 Sodium Thiosull'atc 0.30 H,O 14.00

Density: 1.36 g./cc. Detonation Velocity: 20,1 16 ft./scc. D" Cap Sensitivity: 5 g. pentolitc This composition is prepared by mixing the solid components, and then adding the water, and is of a thixotropic semisolid consistency.

At the bottom end of the container 2 a bottom plate 4 is captured between the bags 2a and 2b. The generally rectangular bottom plate 4 is of wood, and has a rectangular aperture 5 through which a pusher pole 6 is inserted via a slit 7 in the end of the container 2. The pusher pole 6 is also rectangular in cross section, and closely fits in the rectangular aperture 5. The plate engages the sides of the pole, so as to prevent relative rotation, as can best be seen by reference to FIG. 2. In addition, it can be seen that the plate 4 engages the pole 6 over a distance equal to the thickness of the plate. This tends to keep the pole generally perpendicular to the plate, and prevents the pole piercing the wall of the container 2. A loop of detonating cord 10 is positioned partially with the container. The free ends of the loop are formed into a knot 12 which is located within the mass of the explosive 3. The knot 12 serves as the detonator for the explosive 3. A second knot 11 is located in the container adjacent a lower closure clip 14 which holds the end of the bag 2b closed. Another closure clip 14 holds the bag 2a closed. Any form of closure could be used for the bags. The knot 11 abuts the clip 14 on the inner bag 2b. This prevents the fuse from being pulled from the container when the packaged explosive is positioned at the blast site.

The assembly was produced by first inserting the bottom plate in the bag 2a. The bag 2b was then placed inside of the bag 2a on top of the plate 4. The initiating cord was then positioned in the bed with the knot 11 adjacent the opening of the bag 2b. The fuse had a portion that extended out of the container and was held in place while the explosive composition was then poured into place in the package. The ends of the bags were sealed with clips 14. In order to use explosive package, a slit was formed in the bottom of the container 2 and the extending loop of the detonating cord was tied in a knot 16 to a downline fuse 15. The pusher pole 6 was then inserted through the slit and through the central aperture of the plate into the explosive composition. The bag was then wedged into position without the pusher pole penetrating the front end of the bag, and without any rotation of the explosive package on the pole.

The embodiment shown in FIG. 3 is similar to that shown in FIG. 1 with the exception that in this embodiment the plate is made of polypropylene and is formed with a well 20. The well is rectangular, to match the cross-sectional shape of the pole end, and is of a size sufficient to accommodate the end of the pusher pole 6, and prevent rotation. In this embodiment, the well provides a bottom surface against which the pole bears when the package is jammed into position. In this embodiment, the fuse is tied to the plate through apertures 9, and the plate itself forms the bottom of the container. A peripheral heat seal 25 can be conveniently formed between the periphery of the plate 4 and the container 2. When sealed in this manner, the package can be used for very thin slurries and liquid explosives of low viscosity. This is possible since the only possible place that leakage could occur would be through the apertures 9 in the plate through which the detonating cord is located. These apertures 9, are small and can be made to fit tightly about the detonating cord. Thus, if leakage occurs at all, it will be minimal. The explosive used was of the following composition:

TNT 21.00 NH,NO (grained) 60.00 NaNO; (coarse) 8.00 CaCOi 0.4 Petrolatum 0.6

Carbonaceous Material 10.00

Density: 1.49 gJcc. Detonation Velocity: 12,000 ftJsec. 0" Cap Sensitivity: No. l test cap This composition was prepared by mixing the components and was of granular consistency.

A further embodiment of this invention is shown in FIG. 4. This embodiment is similar to that shown in FIG. 1 with the exception that the plate 4 is heat-bonded to the exterior of the container 2, which is a single bag of polyethylene. In the embodiment as shown in FIG. 4 the fuse knot 12 is embedded in a pentolite booster 27, which is cast about it. The booster aids in the initiation of the explosive 3, and also abuts the clip 14 so as to prevent the fuse from becoming accidentally dislodged. In this embodiment as in the other embodiments, the plate has a rectangular aperture which engages the pole, and prevents rotation of the explosive package on the pole. The engagement of the plate and pole also keeps the pole and package in axial alignment. The flange 28 on the pole prevents the pole from being pushed too far through the plate, and also aids in keeping the packaged explosive and the pole aligned. The explosive composition used was the following:

Nitrostarch 10.00 NH NO (grained) 60.00 NaNO; (coarse) 17.50 Nutmeal 12.00

Mineral Oil 0.35

ZnO 0.15

Density: 1.17 g./cc. Detonation Velocity: 6,000 ftJscc. D" Cap Sensitivity: No. 2 test cap The explosive composition was prepared by mixing the components and was of a granular consistency.

The embodiment shown in FIG. 5 is similar to that shown in FIGS. 1 and 2, in that a double bag construction is is employed. In this embodiment, however, the plate 30 is made from a rigid plastic material such as polystyrene, and is formed with a series of perforations which define the outline of a toothed generally round opening 32. A round pusher pole 35 is used and when the pole 35 is forced against the perforated plate the toothed opening 32 is formed in the plate so that the pole can be forced through. The teeth 36 engage the round pole and prevent relative rotation of the pole and the plate.

Having regard to the foregoing disclosure, the following is claimed as the inventive and patentable features thereof:

1. A packaged explosive, particularly suitable for use as a bombing charge, and which is positioned at a blast site by use of a pusher pole, comprising, in combination, a generally flexible container; a deformable explosive therein; a fuse for detonating the explosive in the container and extending in part therefrom; and a positioning and support plate means disposed at the bottom of the container, and having means for receiving and removably engaging a pusher pole in a push fit in a manner to fix the container against rotation on the pole, and to aid in keeping the pole and the packaged explosive in relative alignment while the packaged explosive is placed in position at the blast site, and to permit the pole to be withdrawn from the plate means by a pull.

2. A packaged explosive in accordance with claim 1 in which the plate engages the sides of the pole.

3. A packaged explosive in accordance with claim 1 in which the plate is bonded to the container.

41. A packaged explosive in accordance with claim 1 in which the container comprises two bags disposed one within the other, and in which the bottom plate is positioned between the two bag bottoms.

5. A packaged explosive in accordance with claim 4 in which a quantity of fuse is provided in the container for detonating the explosive.

6. A packaged explosive in accordance with claim 1 in which the plate has a central well.

7. A packaged explosive in accordance with claim 1 in which the plate has a central aperture.

8. A packaged explosive in accordance with claim 7 in which the aperture is rectangular.

9. A packaged explosive in accordance with claim 7 in which the aperture is of only slightly greater diameter than the pusher pole.

10. A packaged explosive in accordance with claim 7 in which gripping means are provided on the edge of the aperture.

11. A packaged explosive in accordance with claim 10 in which the gripping means comprise teeth.

12. A packaged explosive in accordance with claim 1 in which the fuse has a booster charge attached thereto.

13. A packaged explosive in accordance with claim 1 in which the container is made of a flexible plastic material.

14. A packaged explosive in accordance with claim 1 in which the plate is made of a plastic material.

15. A packaged explosive in accordance with claim 1 in which the plate comprises the bottom of the container.

16. In combination, a packaged explosive in accordance with claim 7 and a pusher pole disposed through the aperture and having means adapted to engage the plate, said means being positioned on the pole a distance from the end less than the length of the bag.

17. The combination defined by claim 16 wherein the means on the pusher pole is a flange.

18. A packaged explosive comprising, in combination, a flexible bag; a deformable explosive therein; a plate means disposed at the bottom end of the bag, said plate means having an aperture to receive and position a pusher pole for positioning the packaged explosive at the blast site, said aperture engaging the sides of the pusher pole in a push fit so as to fix the plate against rotation relative to the pole, and said plate means supporting the explosive in the bag with the aperture removably engaging the pole so as to aid in keeping the pole and the packaged explosive in alignment and to permit withdrawal of the pole from the aperture by a pull; a fuse extending, in part, from the top end of the bag; closure means holding the bag closed about the fuse, said fuse having a knot positioned adjacent to the closure means on the bag so as to prevent the fuse from becoming dislodged from the bag when the explosive package is positioned at the blast site.

Claims (18)

1. A packaged explosive, particularly suitable for use as a bombing charge, and which is positioned at a blast site by use of a pusher pole, comprising, in combination, a generally flexible container; a deformable explosive therein; a fuse for detonating the explosive in the container and extending in part therefrom; and a positioning and support plate means disposed at the bottom of the container, and having means for receiving and removably engaging a pusher pole in a push fit in a manner to fix the container against rotation on the pole, and to aid in keeping the pole and the packaged explosive in relative alignment while the packaged explosive is placed in position at the blast site, and to permit the pole to be withdrawn from the plate means by a pull.

2. A packaged explosive in accordance with claim 1 in which the plate engages the sides of the pole.

3. A packaged explosive in accordance with claim 1 in which the plate is bonded to the container.

4. A packaged explosive in accordance with claim 1 in which the container comprises two bags disposed one within the other, and in which the bottom plate is positioned between the two bag bottoms.

5. A packaged explosive in accordance with claim 4 in which a quantity of fuse is provided in the container for detonating the explosive.

6. A packaged explosive in accordance with claim 1 in which the plate has a central well.

7. A packaged explosive in accordance with claim 1 in which the plate has a central aperture.

8. A packaged explosive in accordance with claim 7 in which the aperture is rectangular.

9. A packaged explosive in accordance with claim 7 in which the aperture is of only slightly greater diameter than the pusher pole.

10. A packaged explosive in accordance with claim 7 in which gripping means are provided on the edge of the aperture.

11. A packaged explosive in accordance with claim 10 in which the gripping means comprise teeth.

12. A packaged explosive in accordance with claim 1 in which the fuse has a booster charge attached thereto.

13. A packaged explosive in accordance with claim 1 in which the container is made of a flexible plastic material.

14. A packaged explosive in accordance with claim 1 in which the plate is made of a plastic material.

15. A packaged explosive in accordance with claim 1 in which the plate comprises the bottom of the container.

16. In combination, a packaged explosive in accordance with claim 7 and a pusher pole disposed through the aperture and having means adapted to engage the plate, said means being positioned on the pole a distance from the end less than the length of the bag.

17. The combination defined by claim 16 wherein the means on the pusher pole is a flange.

18. A packaged explosive comprising, in combination, a flexible bag; a deformable explosive therein; a plate means disposed at the bottom end of the bag, said plate means having an aperture to receive and position a pusher pole for positioning the packaged explosive at the blast site, said aperture engaging the sides of the pusher pole in a push fit so as to fix the plate against rotation relative to the pole, and said plate means supporting the explosive in the bag with the aperture removably engaging the pole so as to aid in keeping the pole and the packaged explosive in alignment and to permit withdrawal of the pole from the aperture by a pull; a fuse extending, in part, from the top end of the bag; closure means holding the bag closed about the fuse, said fuse having a knot positioned adjacent to the closure means on the bag so as to prevent the fuse from becoming dislodged from the bag when the explosive package is positioned at the blast site.

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