Device for sealing blast holes

Abstract

Device for closing blast holes, comprising a rod (6) at one end of which at least one expansion element (5), similar to that of an expansion plug, is arranged, wherein the expansion element (5) is dimensioned to fit the clear width of the explosive charging hose (1) and the borehole diameter, and at the other end of the rod (6) a sealing plug (7), larger than the outer diameter of the explosive charging hose (1) and larger than the inner diameter of the through-blast hole (3), is located to fit the through-blast hole opening, and wherein the expansion element (5) is a spring-elastic plastic molded part or preferably a spring-loaded or spring-loaded metal part and is designed so that it can be slidably inserted into the explosive charging hose (1), has a sufficient clamping effect by means of frictional friction when the explosive charging hose (1) is carefully withdrawn into the through-blast hole opening.retains in order to pull the sealing plug(4) back into the same and detaches from it when the explosive charging hose(1) is jerkily withdrawn and wherein the sealing plug(4) is preferably cylindrical in shape and made of suitable foam or is designed as a cuff made of rubber, leather, felt or another suitable material.

Description

The invention relates to a device for closing one side of through-hole blast holes in preparation for the injection of explosives into these blast holes. These through-boreholes are positioned between two parallel main boreholes on a level surface during the driving of a transverse borehole on both sides, with the future chamber columns remaining in the natural rock mass. These transverse boreholes are driven until a load-bearing rib several meters long (up to 7 meters) remains in the center of the future chamber columns. To detonate this final rib between the future chamber columns, through-boreholes are drilled to introduce ammonium nitrate prills into this ribhole, with one of the borehole openings—namely, the one facing the rock mass—being sealed. It is a known practice, in preparation for blasting the footbridge, to seal these through blast holes on one side with a wooden plug to prevent the unintentional falling out of the explosive granules being placed into the blast bore. For this purpose, the already completed main locations are accessed using a mobile elevating work platform, and the wooden plug is driven into the borehole opening by a miner. This process is relatively labor-intensive due to the need to navigate around the future chamber pillars. If a through-blast hole opening is not accessible with a mobile lifting platform for the purpose of sealing it, it remains open. The through-blast holes are pre-blasted with explosives and then filled with ammonium nitrate prills via a blasting hose. During this process, unused explosive granules enter the raw salt mining product, which are then painstakingly removed. The object of the invention is to create a device for closing through-blast hole openings in order to rationalize blasting operations. According to the invention, such a closure device consists of a rod 6 at one end of which at least one expanding element 5, similar to that of an expansion anchor, is arranged, wherein the expanding element 5 is dimensioned to fit the clear diameter of the explosive charging hose 1 and the borehole diameter, and at the other end of the rod 6 a sealing plug 7, larger than the outer diameter of an explosive charging hose 1 and larger than the inner diameter of a through-hole blast hole 3, is located to fit the through-hole. The expanding element 5 is a spring-elastic plastic molded part or preferably a spring-loaded or spring-loaded metal part and is designed such that it can be slidably inserted into the explosive charging hose 1, has a sufficient clamping effect by means of frictional friction when the explosive charging hose 1 is carefully withdrawn into the through-hole blast hole 3, and / or...The sealing plug 4 is retained to retract into the borehole opening and detaches from it when the explosive charging hose 1 is abruptly withdrawn. The sealing plug is preferably cylindrical and made of suitable foam or is designed as a cuff of rubber, leather, felt, or another suitable material. The invention offers the advantage of a simpler, faster, and therefore more cost-effective method for sealing through-hole blasts, instead of using wooden plugs. After using the sealing plug according to the invention, the blast sites can be operated without further mechanical securing or manual re-release, thus eliminating the need for large equipment such as mobile lifting platforms, etc. Furthermore, this reduces the amount of rock explosive based on ammonium nitrate prills and mineral oil entering the raw salt, thus increasing its purity, saving explosives, and minimizing contamination of the raw salt with explosive residues, thereby also reducing the costs of separating them from the raw salt. In this way, any remaining metal remnants from the sealing device can also be easily removed from the raw salt using the magnetic separator without any special effort. The invention is explained below using an exemplary embodiment. In the accompanying drawing, Fig. 1 shows the sealing device in the borehole, and Fig. 2 shows the sealing device schematically. Example During chamber-pillar mining in the potash mine, a blast is prepared, for which ammonium nitrate prills are introduced into a through-bore blast hole 3 with a diameter of 38 mm using an explosive charging hose 1. To close one of the through-bore blast openings, the explosive charging hose 1, with its end leading into the through-bore 2, is fitted with the sealing device 4 according to the invention by first inserting the expanding element 5 into the explosive charging hose 1 until it reaches the stop against the sealing plug 7. The explosive charging hose 1 is then inserted into the through-bore 3 with the sealing plug 7, which, being made of RG18 foam with a diameter of 5 cm and a length of 3 cm, causes noticeable frictional resistance.As soon as the end of the through-bore is reached, the friction noticeably decreases, indicating that the sealing plug 7 is located outside the through-bore 3. The explosive charge tube 1, with the sealing plug 7, is then carefully pulled back against the frictional resistance in the through-bore 3 until it is again wholly or partially inside the through-bore 3. This allows the expanding element 5 to engage the rod 6 with the explosive charge tube 1 by frictional engagement. Once this has occurred, the explosive charge tube 1 is pulled back with a sharp jerk, causing the expanding element 5 to overcome the static friction by frictional engagement with the inside of the explosive charge tube. The sealing device 4 with the sealing plug 7 remains in the through-bore 3.

Claims

Device for closing blast holes, comprising a rod (6) at one end of which at least one expansion element (5), similar to that of an expansion plug, is arranged, wherein the expansion element (5) is dimensioned to fit the clear width of the explosive charging hose (1) and the borehole diameter, and a sealing plug (7), larger than the outer diameter of the explosive charging hose (1) and larger than the inner diameter of the through-blast hole (3), is located at the other end of the rod (6), fitting the through-blast hole opening, and wherein the expansion element (5) is a spring-elastic plastic molded part or preferably a spring-loaded or spring-loaded metal part and is designed so that it can be slidably inserted into the explosive charging hose (1), has a sufficient clamping effect by means of frictional friction when the explosive charging hose (1) is carefully withdrawn into the through-blast hole opening.retains in order to pull the sealing plug(4) back into the same and detaches from it when the explosive charging hose(1) is jerkily withdrawn and wherein the sealing plug(4) is preferably cylindrical in shape and made of suitable foam or is designed as a cuff made of rubber, leather, felt or another suitable material.

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