RU2345319C2 - Method of explosive ore and rock rupture within underground survey and open cast mining - Google Patents

Abstract

FIELD: blasting operations.

SUBSTANCE: invention refers to mining engineering. Method of explosive ore and rock rupture within underground survey and open cast mining includes drilling of parallel-contiguous well bundle, charging and simultaneous blasting. In each parallel-contiguous well bundle, charged wells form modelled surface of cumulative cavity, symmetry axis of which matches path of least resistance. All wells in the bundle outside of this surface, are charged, and all wells inside are not charged. Herewith number N₁ of not charged wells d₁ in internal volume of cumulative surfaces is calculated from the expression: N₁=(k_p-1)(0.5B²-Nd²)/(d²+(k_p-1)d₁ ²), where k_p>1 is degree of fragmentation of blasted rock, B is width of well bundle, m; N is total amount of charged wells in bundle, pc.; d is diameter of charged wells, m; d₁ is diameter of not charged wells, m.

EFFECT: higher application efficiency of parallel-contiguous well bundle energy due to its maximum concentration towards path of least resistance.

2 dwg

Description

The invention relates to mining and, in particular, to underground or open-cast mining of solid mineral deposits with the destruction of rocks or ores due to the energy of the explosion.

A known method of destruction of rocky ores and rocks overhead charges with cumulative excavation in the body of the charge itself [1].

The disadvantage of this method is the limited scope only for the destruction of oversized pieces by placing the charge on the outer surface of these pieces.

There is also a method of destruction of rock masses with hole charges with a longitudinal cumulative recess [2].

The disadvantage of this method is the high complexity of the artificial formation of the cumulative excavation and the small scale of destruction, limited mainly by the area of the mine workings.

The closest in technical essence of the method and the achieved result is a method of destruction for technological purposes of mountain ores and rocks by beams of parallel-parallel wells [3].

The disadvantage of this method is the symmetric nature of the distribution in the destructible array of energy released during the explosion of each beam of wells, and therefore, significant losses of this energy in the contour array, compensated in each case by the additional consumption of explosive.

The aim of the invention is to increase the energy efficiency of the beam of parallel-parallel wells due to its maximum concentration (cumulation) in the direction of the line of least resistance.

The essence of the invention lies in the fact that when rocks are destroyed by beams of parallel-parallel wells in each of them, one or several surfaces of cumulative cavities of the required shape are formed from charged wells, in each of which the direction of the axis of symmetry coincides with the technologically determined direction of the energy flux of the exploded beam. All the wells of the beam located outside of these surfaces are charged, and all the wells inside them are left uncharged.

The number (N ₁ ) and diameter (d ₁ ) of these non-charged wells are selected from the conditions of placement in them of an additional volume of rock formed during crushing of rock gaps between all wells of the beam. With the simultaneous explosion of all charged wells of the beam, all elements of the material in the spaces between the wells acquire speed in the direction of its geometric center. As a result of inertial compression of the resulting gas mass, a gas-jet stream is formed with a velocity vector directed along the axis of the cumulative recess towards its base. This jet, concentrating in itself at least 70% of the total energy of the cumulative charge, produces the destruction of the rock to a bare surface. At the same time, unproductive energy consumption is reduced at least twice compared to the prototype.

The invention is illustrated by drawings, in which Fig. 1 shows a schematic diagram of the formation of a cumulative beam of parallel-contiguous wells, and Fig. 2 is a diagram illustrating the mechanism of formation of a gas-jet stream when blasting a cumulative beam of parallel-contiguous wells.

A method of explosive destruction of ores and rocks in underground and opencast mining includes rechargeable wells 1 in a beam 2; the forming surface 3 of the cumulative cavity 4, the shape of which in cross section along the horizontal plane can be triangular, hemispherical or parabolic with respect to axis 5; non-rechargeable wells 6, elements of material 7 between the wells, geometric center 8, gas-mass 9, gas-jet 10 with velocity vector 11.

The method is implemented as follows.

Based on the type of rocks used by the explosives and the technical capabilities of the drilling system, the number of charged wells N with a diameter d in the well bundle is determined and its shape is equivalent in energy to the calculated single charge in a well with a diameter D:

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The distance between the charged wells in the beam a is taken equal to the sum of the radii of the blasting zones (R _b ) of unit adjacent charges calculated by known methods:

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According to the drilling conditions, the diameter of non-charged wells d _{1 is} taken and their number N _{1 is} calculated:

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If, according to the drilling conditions, the diameters d and d ₁ are taken equal, then the calculation of N _{1 is} carried out according to the formula:

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Drilling in each beam of charged wells 1 with a diameter of d is carried out by one of the known methods (Fig. 1). At the current level of development of drilling equipment, drilling rigs with hydroperforators are the most rational. In this case, regardless of the general shape of the beam 2, part of the charged wells 1 are located along the generatrix surface 3 of the cumulative cavity 4. The shape of this surface in section along the horizontal plane, depending on the technological tasks, can be triangular, hemispherical or parabolic relative to axis 5.

Inside the volume of this cavity 4 are drilled, also by one of the known methods, non-charged wells 6 with a diameter of d ₁ . After drilling, the charged wells 1 in each beam 2 are filled with one of the known types of explosives and blown up simultaneously using one of the known initiation methods. The effect of increasing the energy concentration of the explosion in the direction of the line of least resistance (Fig. 2) is achieved by the fact that, due to the action of known physical laws, all elements of the material 7 in the spaces between the wells acquire speed in the direction of the geometric center 8 of the cumulative cavity 4. As a result of inertial compression of the resulting gas-porous of mass 9, a gas-specific jet 10 is formed with a velocity vector 11 directed along the axis of symmetry 5 of the cumulative cavity 4. In this gas-specific jet 10, which produces directionally destruction of rock, concentrated at least 70% of the total energy of the shaped charge that is 2-2.5 times greater proportion of energy used for the destruction of the array by using parallel beams of adjacent wells of conventional construction.

The scope of the proposed method of explosive destruction is the explosive preparation of detachable cracks, the reduction of contouring during layer excavation of low-power ore bodies, the creation of additional outcrop planes during the breaking of large blocks in quarries.

Information sources

1. Medvedev I.F., Abramov A.V., Nefedov A.P. Elimination of freezes and secondary crushing of ores. M., Nedra. 1975, 197 p.

2. Deminyuk G.P., Vedutin V.F. Explosion efficiency during mine workings. M., Nedra. 1973, 152 p. (Pp. 83-93).

3. Budko A.V., Zakalinsky V.M., Rubtsov S.K., Blinov A.A. Improving downhole breaking. M., Nedra, 1981, pp. 74-87.

Claims (1)

The method of explosive destruction of ores and rocks in underground and opencast mining, including drilling bundles of parallel-parallel wells, loading and simultaneous blasting, characterized in that in each bundle of parallel-parallel wells they form a surface of a cumulative cavity of a given shape from charged wells, the direction of the axis of symmetry of which coincides with the line of least resistance, while all the wells of the beam located outside of this surface are charged, and all the wells inside it are left unattended mummers, the number N _{1 of} non-rechargeable wells d ₁ in the internal volume of the cumulating surface is determined from the expression:

,
where k _p > 1 is the coefficient of loosening of the blasted rock;
In - the width of the beam of wells, m;
N is the total number of charged wells in the beam, pcs .;
d is the diameter of the charged wells, m;
d ₁ - diameter of non-rechargeable wells, m

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