RU2119054C1 - Method for destruction of ore plugs - Google Patents

Abstract

FIELD: mining industry. SUBSTANCE: this relates to destruction of ore plugs in ore chutes, draw holes, etc. According to method, destruction of ore plugs is effected by firing one or several shaped charges filled with shattering explosives with mass of 1-30 kg, density of 1250-1900 kg/cu.m, and detonation velocity of 4500-8300 m/s. Shaped charge is installed at distance of 1-50 m from lower edge of ore plug. Shaped charge is oriented with base of its metallic shape lining directed towards ore plug to be destructed. Thickness of shape charge lining is 0.002-0.01 m, mass is 0.05-5 kg, height over internal surface is equal to 0.05-0.3 of diameter of shape charge lining. EFFECT: higher efficiency. 8 dwg, 5 ex

Description

 The invention relates to blasting and can be used for remote destruction of ore plugs (elimination of freezes) in ore passages, exhaust chutes of ore passages, duchki.

 With the existing technology of mining in underground conditions, the delivery and release of ore to the horizon is accompanied by the formation of ore plugs (hangs) both in ore passages and in inlet devices, for example, in exhaust chutes of ore passages and dukes.

 Ore freezing (formation of ore plugs) occurs mainly for two reasons: either due to the ingress of oversized pieces, or due to the accumulation of ore fines, followed by crushing of the rock by falling pieces of ore.

 The formation of hangs (ore plugs) disrupts the normal operation of mining enterprises and leads to a significant decrease in labor productivity due to the need for their rapid elimination. Explosive elimination of hangs is usually done by using overhead charges from Ammonite 6ZHV, which are allowed in direct contact with the surface of the rock. The destruction of ore plugs in the vertical part of the ore pass (between walkers) is due to the impact of an air shock wave generated by the detonation of charges with a total mass of up to 100 kg and more. The charge, as a rule, does not concern the destructible arch, therefore, the intensity of its impact is small.

 At the same time, a number of methods are known for eliminating ore freezes (for example, in deep ore passages), based on the use of rockets of both contact action and penetrating deep into the ore plug like concrete-piercing artillery shells (Yu.V. Misnik, V.A. Borovikov , V.V. Komarov, V.I. Petukhovsky. On the selection of fundamentally new means of eliminating ore freezes in deep ore passages, in the collection Explosive Affairs, 59/16, M. Nedra, 1966, pp. 226 - 237, 284 pp.) .

 The main disadvantages of this method include: the complexity of the design and operation of the proposed devices, the presence of a detonator and a propellant charge in them, which lead to a high cost of eliminating freezes if it is necessary to ensure a high level of safety during transportation, storage and use, the inability to reuse propelling devices in view of their destruction, as they remain in the zone of ore fall.

 When carrying out work in underground conditions, the release of a significant amount of harmful gases released during the burning of powder charges of propelling devices is also significant.

 In order to increase the efficiency of blasting operations to eliminate ore plugs at acceptable safety indicators, it is proposed to use long-range cumulative charges capable of forming and throwing compact metal elements during the explosion, which maintain their continuity (integrity) at significant distances from the initial charge.

This goal is achieved by the fact that the explosive destruction of plugs in ore passages, mines is carried out by blowing up one or several cumulative charges filled with blasting explosives weighing from 1 to 30 kg, a density of 1250 - 1900 kg / m ³ and a detonation speed of 4500 - 8300 m / s, while the cumulative charge is located at a distance of 1 to 50 m from the lower cut of the ore plug, orienting the cumulative charge with the base of the metal cumulative lining in the direction of the ore plug to be destroyed, and the cumulative lining has a thickness of 0.002 - 0.01 m, weight 0.05 - 5 kg and a height on the inner surface equal to 0.05 - 0.3 of the diameter of the lining.

 The invention is illustrated by drawings, where in FIG. 1 - shows the basic design of long-range cumulative charge (DKZ); in FIG. 2 is a schematic diagram of the formation of a metal element when undermining a long-range cumulative charge (DKZ); in FIG. 2a - a metal element in an intermediate stage; in FIG. 2b - metal element at the final stage; in FIG. 3 is a schematic diagram of the destruction of an oversized piece of rock when exposed to a metal element; in FIG. 4 is a diagram of the use of DKZ for the destruction of ore plugs in the vertical part of the ore pass; in FIG. 5 is a diagram of a DKZ installation with the simultaneous detonation of several charges; in FIG. 5a is a section along AA in FIG. 5; in FIG. 5b is a section along BB in FIG. 5; in FIG. 6 is a schematic diagram of the use of DKZ in the destruction of ore plugs in duchki, exhaust workings; in FIG. 6a is a view along AA in FIG. 64 in FIG. 7 - a schematic diagram of the installation of DKZ; in FIG. 8 is a view along AA in FIG. 7.

 Long-range cumulative charge (DKZ) depicted in FIG. 1 includes a detonator capsule (electric detonator) 1, an intermediate detonator 2, a housing 3 DKZ, explosive 4 explosive charge, lining 5 DKZ, in FIG. 1 - N - the height of the inner surface, D - the diameter of the base of the cladding.

 A diagram of the process of forming a compact metal element is shown in FIG. 2. When initiating the detonator capsule 1 during the detonation of explosive charges 4, as a result of compression of the cumulative lining 5 by detonation products 8 from the front of the detonation wave 6, a compact metal element 7 is formed, having a speed of 1000 - 3000 m / s and maintaining its continuity at distances up to several hundred charge diameters. The mass of such an element significantly exceeds the mass of the cumulative jet formed by the classical cumulative charge and can reach 70 ... 80 percent of the initial mass of the cladding. Moreover, in FIG. 2a shows a metal element 7 in an intermediate stage, and in FIG. 2b - at the final stage of formation before interacting with an ore plug or oversize.

 A schematic diagram of the destruction of a fragment of an ore plug (oversized piece) when exposed to a metal element (ME) 7 is shown in FIG. 3.

 Upon collision with an oversized piece of rock 9 of a metal element 7 having a kinetic 5000 - 7000 kJ, crack formation 10 occurs in this rock, partial destruction of the rock material in the impact region. As it is introduced into the rock fragment, the metal element 7 deforms, and the cracks merge to form new free surfaces, subsequently leading to the formation of final fragments 11 and the destruction of the initial oversized rock fragment. The action of such an element is equivalent to the use of an overhead charge of an explosive (having a height equal to a diameter), for example, Ammonite 6ЖВ, weighing 0.5 - 7 kg.

 Charges of this type have a certain distribution in military equipment and are intended for remote destruction of armored vehicles, for example, XM24 anti-aircraft mines (USA), MAN MOD. XI (France), ATM-6 (Austria), capable of forming metal impact cores flying at a speed of up to 1800 m / s and hitting armor at a distance of several tens of meters (N. Zhukov. Anti-tank mines. Foreign military review, 11, 1986 , pp. 20 - 28, 80 s). However, it is natural that the use of charges identical in design to anti-tank mines in underground conditions is impractical both because of their high cost and because of the increased danger of their operation.

Therefore, industrial long-range cumulative charges used for explosive elimination of ore freezes in ore slopes and mines must satisfy the following requirements: requirements for explosive charges:
burst density (RE) 1250 kg / m ³ corresponds to a charge of a water emulsion explosive of the poremite type, having a detonation velocity of 4500 m / s and providing a level of throwing parameters sufficient to form a metal element with kinetic energy up to 2 - 3 MJ, for example, under blasting DKZ with a steel cladding with a thickness of 6 - 8 mm and an inner diameter of the cladding of 250 mm with an angle of conical cladding solution of 155 degrees and a burst mass of explosive charge of 16 - 17 kg;
the use of cast charges, for example, based on TNT / RDX / oxidizer mixtures in the range of TNT concentrations of 20 ... 40 mass percent, allows to obtain REs having a density of 1800 - 1900 kg / m ³ and a detonation speed of up to 8000 m / s, which in turn, it provides the possibility of producing metal elements with kinetic energies of up to 8 - 9 MJ, when functioning DKZ having, for example, steel cladding with a diameter of 300 mm and a thickness of 8 - 10 mm, with a mass of RE up to 20 kg;
the minimum RE mass - 1 kg - is determined by the lower limit of the kinetic energy reserve of the metal element at the level of 0.3 - 0.5 MJ, which is necessary for the stable destruction of a piece of rock of medium strength with a size of 0.3 - 0.4 m (respectively 0.009 - 0, 0064 m ³ ) during the elimination of freezing in the dam;
the restriction of the mass of REs - 30 kg is due to a decrease in the efficiency of work both due to a decrease in the efficiency of the DCE, and because of an increase in the preparation of the explosion and an increase in the amount of harmful gases in the detonation products of explosives.

Design requirements for DKZ:
The presence of the lower and upper limits on the dimensions of the inner diameter of the DKZ lining is explained by the need to ensure a minimum level of kinetic energy of the metal element to destroy a piece of rock with a size of at least 0.3 m and an increase in the cost of work when using DKZ with a lining with a diameter of more than 300 mm due to the large explosive mass charge DKZ.

 The existence of a restriction on the relative height of the cumulative lining is explained by the fact that when collapsing lining with an H / D ratio of more than 0.3, a cumulative stream is formed that is not able to produce destruction at large distances from the charge due to its decay into individual particles due to high velocity gradients. In the case of using claddings with an H / D ratio of less than 0.05, the compact element practically does not form due to the collapse of the cladding into individual fragments already at distances equal to 1-3 diameters of the charge from the base of the cladding, since the throwing process occurs similarly to throwing a metal plate placed at the end of the charge.

 The restriction of the distance to the ore plug being destroyed by the range of 1 - 50 m is due to the fact that at a distance of less than one meter the formation of the element is not yet completed, and at distances of more than 50 m the probability of the element getting into the side surface of the ore pass (duchka) increases.

Examples of the use of long-range cumulative charges of various designs for crushing a piece of rock with a density of 3280 kg / m ³ , a compressive strength of 2820 kg / cm ² (poor magnetite ore) with an initial size of 1000x600x400 mm (a metal element hit the surface of the piece with the largest area).

 The principal sequence of work to eliminate the hangs according to option I (Sequential impact of single DKZ on the ore plug) is shown in FIG. 4.

 The destruction of the ore plug in the vertical part of the ore pass is as follows.

 On the ground of the lower (with respect to the ore plug) sight glass 12, for example, a 40–50 mm thick board with a stiffening rib (25–30 mm thick board) or a metal corner 13 with a counterweight 14 are installed.

At the end of the board, DKZ 15 is installed and fixed, oriented with the base of the cumulative lining in the direction of the ore plug, and the angle between the axis of the DKZ and the axis of the ore pass is 5 - 10 ^o when the ore plug is destroyed at a distance of 10 m and not more than 2 - 5 ^o when the ore is destroyed traffic jams at a distance of more than 10 m.

 A detonator capsule (electric detonator) 1 or a detonating cord (depending on the design of the DKZ initiation unit) is inserted into the socket of the additional DKZ detonator.

 The board with the DKZ is put forward so that the DKZ is on the axis of symmetry of the ore pass 16 (in case of impossibility to visually determine the cause of the hover), or by orienting the charge in the direction of the destructible hover section 17 (the central part of the oversized piece).

 They fix the end of the board located on the ground of the walker, for example, a counterweight 14 from pieces of rock, install the explosive network, leave the danger zone and undermine the DKZ.

 In case of incomplete failure of the hang, the operation is repeated.

 The procedure for the elimination of freezes according to option 2 (the simultaneous effect of several DKZ on the ore plug) is presented in FIG. 5, 5a, 5b.

 The work is carried out similarly to option 1. The difference is in the preparation of the blasting: several DKZ 15 can be installed on one board 13 or on an assembly platform consisting of several boards fastened together, for example, according to the diagram of FIG. 5, where position 18 shows the blasting network, position 19 shows the whole rock and position. 30 - walker.

 When blasting according to option 2, the condition for ensuring simultaneous blasting is additionally imposed in order to exclude the effect of an air shock wave from neighboring charges when undermining a DKZ group.

 The procedure for carrying out work during the destruction of hangs in the chimneys and exhaust chutes of ore passages, exhaust workings (for example, in sub-floor caving systems) is shown in FIG. 6-6a.

 The main difference from the work on the destruction of ore plugs in the vertical part of the ore passes is the possibility of installing DKZ directly on the soil of the walker or on mounting devices. The rest of the order of preparation and conduct of work does not differ from the above options.

 In FIG. 7 - 8 shows an example of using DKZ 15 installed on a special mounting device that allows the elimination of ore plugs located at an arbitrary angle α to the horizon. This device consists of a base 21, for example, a wooden shield, having several holes for accommodating the fixing metal pins 22, and two parallel posts 23, in the upper part of which there is one hole for accommodating the centering pins 24 mounted on the DKZ case. In preparation for the elimination of the ore plug, an installation device is initially installed on the surface of the soil 25, hammering the metal fixing pins 22 into the soil until they stop through the holes in the base 21. Then, passing the centering pins of the DKZ case through the holes in the uprights, tighten them with nuts to such a state so that the housing DKZ was securely fixed, but at the same time could be rotated on the centering studs 24. After that, an aiming device is installed on the side surface of the housing DKZ, representing For example, the tube 26 length 300 - 500 mm with an internal light source 27 placed in the rear part of the tube (from the initiation site). Turning the DKZ case on centering pins, they get a light beam 28 on the surface of the rock to be destroyed, after which the nuts are screwed to the stop, fixing the final installation of the DKZ; mount the explosive network by placing and securing the detonator capsule (electric detonator or detonating cord) 1 in the socket of the additional explosive charge explosive charge detonator DKZ and undermine it.

 The following are examples of specific uses of the present invention.

 Example 1

Design parameters DKZ:
Charge diameter - 150 mm;
Charge height - 115 mm;
Facing: material - steel; thickness - 4 mm; H / D ratio - 0.08
Explosive: density - 1850 kg / m ³ ; detonation speed - 7500 m / s;
The distance to the piece of rock is 3 m.

 The number of simultaneously exploded DKZ is one.

 Efficiency of action: the number and average size of pieces of rock after exposure to an element is 3 400 to 500 mm in size.

 Example 2

Design parameters DKZ:
Charge diameter - 200 mm;
Charge height - 150 mm;
Facing: material - steel; thickness - 6 mm; H / D ratio 0.08;
Explosive: density - 1850 kg / m ³ ; detonation speed - 7500 m / s;
The distance to the piece of rock is 15 m.

 The number of simultaneously exploded DKZ is one.

 Effectiveness of action: quantity and average size of pieces of rock after exposure to an element: 4 pieces of sizes 300 - 400 mm.

 Example 3

Design parameters DKZ:
Charge diameter - 250 mm;
Charge height - 190 mm;
Facing: material - steel; thickness - 6 mm; H / D ratio 0.08;
Explosive: density - 1350 kg / m ³ ; detonation speed - 5000 m / s;
The distance to the piece of rock is 5 m.

 The number of simultaneously exploded DKZ is one.

 Efficiency of action: quantity and average size of pieces of rock after exposure to an element: 2 pieces of size 500 - 600 mm.

 Example 4

Design parameters DKZ:
Charge diameter - 100 mm;
Charge height - 90 mm;
Facing: material - steel; thickness - 4 mm; H / D ratio 0.1;
Explosive: density - 1700 kg / m ³ ; detonation speed - 7900 m / s;
The distance to the piece of rock is 5 m.

 The number of simultaneously exploded DKZ is two.

 Efficiency of action: quantity and average size of pieces of rock after exposure to an element: 5 pieces of size 200 - 300 mm.

 Example 5

Design parameters DKZ:
Charge diameter - 150 mm;
Charge height - 115 mm;
Facing: material - steel; thickness - 4 mm; H / D ratio 0.08;
Explosive: density 1700 kg / m ³ ; detonation speed 7900 m / s;
The distance to a piece of rock is 15 m.

The number of simultaneously exploded DKZ - two;
Efficiency of action: quantity and average size of pieces of rock after exposure to an element: 4 pieces of size 250 - 350 mm.

The proposed technical solution in comparison with the known has the following advantages and allows you to:
to increase the efficiency of ore mining in underground conditions by reducing the downtime of ore passages, ducts (exhaust devices) by reducing the preparation time and the explosive elimination of hangs (ore plugs);
to increase the safety of work by removing personnel from the danger zone;
reduce the amount of harmful gases released during the explosion by reducing the weight of simultaneously exploded explosives.

Claims (1)

A method of destroying ore plugs in ore passages, dukes, according to which explosive destruction of plugs is performed, characterized in that the explosive destruction of ore plugs is carried out by blasting one or more cumulative charges filled with blasting explosives weighing from 1 to 30 kg, density 1250 - 1900 kg / m ³ and detonation velocity of 4500 - 8300 m / s, while the cumulative charge for a distance of 1 - 50 m from the lower edge of the ore tube, orienting the shaped charge of the metal base facing towards cumulative azrushaemoy ore cork, wherein the cumulative cladding has a thickness of 0.002 - 0.01 m, 0.05 weight - 5 kg and a height of an inner surface of 0.05 - 0.3 diameter of the cladding.

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