FI64975C - Method for opening clogged loading hoppers and / or rock shafts in mines and quarry input used in the method. - Google Patents

Description

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National Board of Patents and Registration (44) NthUvilulpanon j. the date of the month. - η in o.

Patent and registration authorities of the United Kingdom of Great Britain and Northern Ireland J J

(32) (33) (31) Requested «tuolkaua — Begird prlorltct (71) Raikka Oy, Tavastst jemankatu 11, 00250 Helsinki 25, Finland-Finland (FI) (72) Tauno Ahola, Kaleton, Finland-Finland (FI) ( 7 * 0 Forssen & Salomaa Oy (5 * 0 Method for opening loading hoppers and / or stone shafts clogged in mines and quarry input used in the method

The invention relates to a method for opening clogged loading hoppers and / or stone shafts in mines, in which method a special firing charge is placed below the opening vault, which is directed to the opening vault.

The invention further relates to a quarry charge used in the method for throwing its projectile in the desired direction.

As is known, the lower end of the mine's hopper is loaded and the quarry that has fallen there is driven away. At the same time, a new quarry flows from the top to replace it. This causes vaults in the loading hoppers, which must be dismantled using explosives. A similar vault also occurs in the stone shafts of the mines.

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A common disadvantage is that the quarry poured into the loading hopper cannot drain down, but the hopper becomes clogged as the larger boulders wedge against each other. These blockages occur at different heights. If said blockage is so low that a hole can be drilled in it without danger, the stone can be broken by blasting, placing the blasting charge in the drilled hole. On the other hand, if the vaulting of loading hoppers and stone shafts takes place so high and in such a way that the boulders caused by the vault cannot be drilled, either because the vault could fall due to the vibration caused by the borehole or the vault is so high that it is not possible to drill. .

The accompanying Figures A and B (prior art) show a currently commonly used method for performing surface charge blasts. In Fig. A, the vault of the rising shaft b is denoted by a: 11a, and an explosion charge d is introduced in connection with the vault a. Figure B shows the structure of the surface explosive charge. The charge includes an explosive charge d with its detonators, an ampurima c, to which a detonator wire e is attached by tie wires f, which leads to the trigger device.

Surface charge blasting is performed by raising the explosive d on or between the boulders causing the vaulting by means of the ribs c and then blasting this surface charge in order to open the blockage. Depending on the size of the boulders, blasts have to be used in blasting, the smallest of which contain a few kilos and the largest several tens of kilos of explosive. When using surface inserts, it is usually necessary to shoot several times before the vault can be opened.

Sometimes the vaulting has taken place at such a high height, e.g. 10-20 meters, that with the help of said ribs it is not possible to raise the surface inserts to a sufficient height. In this case, it is generally known to drill a borehole from an adjacent loading hopper to the vaulting point and through it an attempt is made to push the explosive into the vault, where it is then detonated and thus an attempt is made to open the vault.

The demolition of vaults discussed above is one of the most difficult and dangerous works to be carried out in the mines, for which 3,64975 a workable and safe solution suitable for all cases has not been invented.

In addition, attempts have been made to open said vaults by firing boulders caused by them using explosive ammunition. In this way, part of the vault can be opened, but the great disadvantage is that the weapon used to shoot is buried under falling boulders and shattered, unless expensive and very impractical special arrangements are used, as proposed in SE patent 218,670. Therefore, this method is not economically economical.

The method according to the invention is mainly characterized in that said projectile is used as a quarry charge comprising an explosive body and a massive projectile, e.g. of metal, which

The quarry charge applying the method according to the invention, in turn, is mainly characterized in that the charge comprises a projectile placed on the surface of the explosive body, from which the explosive gases cause a high pressure in the explosive side of the projectile at the desired velocity.

The invention has therefore been based on the finding that explosives can be used to give high exit velocities to ammunition. In this case, however, the actual "weapon" disintegrates when the explosive used as a charge explodes. Thus, the projectile is constructed in such a way that it can withstand the pressure caused by explosive gases, so that the projectile receives a high initial velocity and the desired initial direction. The durability of the "weapon" used need not be made stronger than that it can withstand normal handling, because, however, the "weapon" and its "barrel" will explode in an explosion. Indeed, the most suitable tubular material for a "weapon" is one that breaks into small fragments or gasifies in an explosion. In this case, the disintegration of the "weapon" will not result in fragments causing damage to the environment. For example, plastics are suitable for this purpose.

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The projectile used in the method according to the invention must have a large cross-sectional area which can be influenced by the pressure of the explosive gases. This achieves sufficiently high output speeds for the method.

When there is no tube around the explosive gases in the invention as when using powder, the explosive gases behind the projectile can spread rapidly to the side and the pressure behind the projectile decreases rapidly, so that the pressure of the explosive gases affects the projectile only for a short time. In the tubes of ordinary cannons, the pressure of the gunpowder acts at a distance of about 1-5 meters. In the invention, on the other hand, the effect of the explosion pressure on the projectile takes only a small part of this distance.

Achieving a high initial velocity according to the invention requires a large cross-sectional area and a durable structure for munitions firing with explosives so that the shape of the projectile does not change under the influence of explosive gases. Sometimes, however, it is consciously desired to change the shape of the projectile, e.g. to improve its permeability or flight characteristics.

The projectiles used in the invention are suitably circular plates 10-30 cm in diameter and about 10-30 mm thick. Their upper or lower surface may also be in the form of either a spherical surface, a cone or a truncated cone or the like, in which case the thickness of the edges may be a few millimeters.

Any explosive can be used as the explosive in the invention. However, the highest exit velocities are achieved with explosives with a high explosion rate.

Achieving a high exit velocity requires a large cross-sectional area of the projectile, but in order to achieve a high fracturing capacity of the projectile boulders, it is necessary to concentrate the impact energy of the projectile over a small area.

In the following, the invention will be described in detail with reference to an embodiment of the invention shown in the figure of the accompanying drawing.

Figures A and B of the drawing show the prior art as described above.

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Figure 1 shows a central cross-section of a cartridge according to the invention.

According to Figure 1, the charge 10 comprises an explosive body 11 with e.g. 5-6 kg of explosive surrounded by a thin steel shell 12 of about 1 mm thickness, which is substantially in the shape of a truncated cone. A carrying handle 13 is welded to the steel shell 12 at points 14 and 15. The narrower end of the projectile has a detonator 18 and a detonator hole 19. At the wider end of the explosive body 11 there is a massive projectile 17 used in the method according to the invention. the projectile shell 12. The projectile 17 has a round shape and its planar part comes outwards, i.e. in the firing direction V. The steel shell 12 can in some cases preferably be replaced by a corresponding plastic shell which gasifies during firing. The projectile 17 is, for example, of suitable steel and the weight is about 5 kg in the embodiment according to Figure 1.

The charge 10 shown in Figure 1 gives the projectile 17 an initial velocity of about 1400-1500 m / s in the firing direction. The invention is in no way limited to the charge described in Fig. 1 by way of example only and its described use. The charge can thus be realized, for example, by placing an explosive body corresponding to the explosive body 11 in a molded housing made of e.g. styrofoam and attaching to the explosive body an ammunition used in the invention, the shape of which may differ significantly from the shape described above. .

The method according to the invention is implemented in practice, e.g. by placing a cartridge 10 on a tight and strong base 20 below the rising shaft shown in Fig. A, which is directed towards the vault using auxiliaries known per se and then firing in which the projectile 17 strikes the vault. If necessary, a new shot or more shots are fired until the vault is opened.

When opening loading hoppers or shafts using the method according to the invention, the quarry charge described above is directed at the bottom of the shaft, e.g. with the aid of light-beam orientation, to the desired point of impact. Since the shooting distance to the blockage will usually be about 5-20 m, the speed of the projectile will not be ___ ι.

64975 on this trip to a detrimental extent decrease. If, for example, the impact velocity of a projectile weighing 7 kg is 1000 m / s, then its impact energy will be 3 approx. 3,500,000 Nm. Such impact energy is sufficient to break rocks up to about 2-3 m in size.

As stated above, the cross-sectional area of the projectile 17 should be as large as possible during the explosion, but in the event of an explosion, it is preferable that the cross-sectional area of the projectile is reduced. In this case, the impact energy increases per unit area of the projectile's impact surface, and the projectile's penetration capacity increases. At the same time, the deceleration of the projectile caused by air resistance also decreases. The reduction of the cross-section of the projectile 17 or the like can be achieved e.g. in the following different ways.

The edges of the projectile are made thinner than its center, causing the pressure of the explosive gases to turn them forward. After the explosion, the air resistance turns the projectile 180 °, whereby the cross-sectional area of the projectile is reduced due to the turning of the edges.

The steel plate formed by the projectile is made such that this projectile flies either edge first or on wheels, whereby at least part of the distance the projectile flies edge first. This is achieved by making the projectile asymmetrical.

A plate with a much smaller diameter is placed on top of the plate formed by the projectile. If, for example, the diameter of this plate is 1/3 of the diameter of the lower plate, but the weight is 1/2 of the weight of the lower plate, then the cross-sectional area of the small plate is 1/9 of the surface area of the large plate. When the weight of the small plate is 1/2 of the weight of the lower plate, the cross-sectional load of the small plate is 4.5 times that of the lower plate. When both parts of the projectile have the same velocity, the impact energy per cm of the smaller projectile is 2.25 times the impact energy of the larger projectile plate. In addition, the deceleration caused by air resistance in a smaller projectile is smaller than in a larger one.

The invention is in no way narrowly limited to the details described above by way of example only, which may vary within the scope of the inventive idea defined by the following claims.

Claims (8)

A method in mines for opening clogged loading funnels and / or stone shafts, in which method under the arch to be opened is placed a special sliding charge directed towards the arch to be opened, characterized in that, as said projectile, such an explosive charge comprising an explosive piece (11) and a massive projectile (17) of, for example, metal, which, with the force of the explosive thrust of the explosive, is thrown without a tubular own weapon with a large exit velocity against said arch, while the impact energy of the projectile (17) destroys the stones of the arch. Explosive charge for use in the method of claim 1 for hurling a projectile in the desired direction to open the clogged loading funnels and / or stone shafts in mines by placing on the lower side of the arch to be opened a special sliding charge directed on the arch to be opened, characterized in that the charge (10) comprises a massive e.g. of metal-resistant projectile (17), which is placed on the surface of the explosive piece (11) and that the force of the explosive thrust of the explosive has been arranged to throw the projectile (17) without any actual tubular weapon with a large exit velocity against the arch while the impact energy of the projectile (17) stones, Explosive charge according to claim 2, characterized in that the projectile at the detonation is formed in such a way that its cross-sectional area becomes substantially smaller than before the detonation. Explosive charge according to claim 2, characterized in that as a projectile (17) there is used a sheet of metal or something, which becomes thinner from the center towards the edges, which at the detonation is swung forward, due to which the air resistance swings the projectile c. 180 °, flying with the curved edges facing the rear and with substantially less cross-sectional area than this projectile had before firing. Explosive charge according to claim 2, characterized in that as a projectile there is used a so-formed steel plate which when inserted