RU2738331C1 - Method of explosive preparation for selective excavation of ore body and covering overburden rocks - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: invention relates to mining industry and can be used at open-pit mining at explosive preparation for selective excavation at contact of ore-rock massif including ore body and covering overburden rock. Method involves drilling of downhole wells and their charging with well explosive charges. Lower and upper parts of charges are dispersed by a rock inert interval. Then stemming of wells is performed and charges are initiated. Charges are initiated with the delay-action blasting of the upper part of charges with reference to their lower part. At that blast holes are drilled at design depth by alternating layers of covering rocks and ore body with charges arranged with intermediate detonators equipped with electric detonators. These detonators are provided with electronic programmable deceleration in charge along ore body and non-electric initiation system in charge on covering rocks. Charges are dispersed by grubbing material until contact of ore body with covering rocks. Electric detonators with electronic programmable deceleration are programmed so that initiation of dispersed part of charges along ore body occurred after initiation of part of charges on covering rocks.

EFFECT: technical result is higher quality and completeness of ore extraction due to primary explosion of overburden rock covering ore body and subsequent blasting of ore body in clamped medium with preservation of structure and its position in massif.

1 cl, 7 dwg

Description

The invention relates to the mining industry and can be used in open pit mining during explosive preparation for selective excavation at the contact of ore-rock massif, including the ore body and overburden overburden.

The known method of selective mining of ore (Sukhanov A.F., Kutuzov B.N. The destruction of rocks by explosion. Textbook for universities, 2nd ed., Revised. And additional. M., Nedra. 1983. 238 S.), including blasting a group of charges in conditions where there is no open surface of the blasted block, which is covered by a certain volume of previously destroyed rock.

The disadvantage of this method is the need to leave the previously blasted rock mass to create a buffer, which leads to a decrease in the width of the working platform of the mined horizon.

The known method of preparation of explosive blocks (Sukhanov A.F., Kutuzov B.N. Destruction of rocks by explosion. Textbook for universities, 2nd ed., Revised. And additional. M., Nedra. 1983.320 s), including drilling vertical, inclined or horizontal (slightly inclined) bore-holes with a diameter of 32-70 mm and a depth of up to 5 m; testing of wells by geological and geophysical methods, loading and blasting according to the selected parameters of drilling and blasting operations and the scheme of commutation of borehole charges, excavation of the blasted rock mass according to the selected planogram of mining.

The disadvantage of this method is the additional volume of drilling holes for charging, the need for detailed operational exploration, the need to load and detonate a large number of holes, the complexity of the organization of work when it is necessary to break off significant volumes of rock mass.

There is a known method of short-delayed multi-row blasting of ledges (V.V. Rzhevsky, Processes of open pit mining, Moscow: Nedra, 1978, p. 109), which provides various options for crushing the rock mass by an explosion, accompanied by the movement of the blasted rock mass on the ledge, and the width and the direction of entry of the excavator ensures the sequence of mining.

The disadvantage of this method is the displacement of the ore body and its mixing with the rock relative to the initial mining and geological occurrence, due to the production of short-delayed blasting blasting.

There is a known method of blasting at opencast mines of multi-strength layered rock mass (RF patent No. 2563893, publ. 09/27/2015), taken as a prototype, including the drilling of descending wells, loading them with combined borehole charges of explosive explosive with placement in the lower part of the well powerful explosive. The lower and upper parts of the charges are dispersed by the rock inert gap. A more powerful explosive is placed in the upper part of the wells. Then the wells are plugged and the charges are initiated. In the process of loading, a less powerful explosive in the lower part of the wells is placed to the soil level of a more durable rock layer. The inert gap is performed with a height of 1.75 to 2.5 borehole diameters d. The initiation of charges is carried out with advanced short-delayed blasting of the upper part of the charges relative to their lower part.

The disadvantage of this method is the need to use different types of explosives for the upper and lower parts of the well, as well as the use of short-delayed blasting between the upper and lower parts of the explosive charges, which does not exclude the mixing of ores and overburden during blasting.

The technical result is an increase in the quality and completeness of extraction during subsequent excavator mining, a decrease in losses and dilution of ores at the ore-rock contact due to the primary blasting of the overburden covering the ore body and subsequent blasting of the ore body in a compressed environment while maintaining its structure and position in the rock mass, as well high-quality crushing of the ore body and reduction of the hazardous zone by the scattering of individual pieces of rock mass and the action of the air shock wave are achieved.

The technical result is achieved by the fact that blast holes are drilled to the design depth along alternating layers of overburden and the ore body with the placement of charges with intermediate detonators equipped with electric detonators with electronic programmed slowdown in the charge along the ore body and a non-electric initiation system in the charge over the overburden, and the charges are dispersed by the face material until the ore body contacts the overburden, and the electronic programmable retardation electric detonators are programmed so that the initiation of the dispersed part of the charges over the ore body proceeds after the initiation of some of the charges over the overburden.

The method is illustrated by the following figures:

fig. 1 - flow diagram of the method of explosive preparation,

fig. 2 - diagram of the design of the borehole charge,

fig. 3 - diagram of the blown up mountain range;

fig. 4 - the initial state of the massif, where the ore body covers a layer of overburden;

fig. 5 - modeling of advanced short-delayed blasting of rocks covering the ore body;

fig. 6 - simulation of the subsequent blasting of the ore body in the clamped environment with an interval of 2 seconds after the initiation of the last well through the overburden;

fig. 7 - the resulting collapse of the rock, where:

1 - ore body

2 - overburden;

3 - blast holes;

4 - explosive charge;

5 - intermediate detonator;

6 - stemming material;

7 - end wires and (or) waveguides;

8 - collapse of blasted overburden.

The method is carried out as follows. The method of blasting in open pit mines, includes mine surveying of the block, drilling to the design depth of descending wells along alternating layers of overburden 2 (Fig. 1) and ore body 1, charging blast holes 3 (Fig. 2) with placement of explosive charges 4 in each layer with intermediate detonators 5 equipped with a non-electric initiation system for short-delayed blasting in a charge over the overburden 2 and electric detonators with an electronic programmable retardation over the ore body 1, and the explosive charges 4 are dispersed by the face material 6 until the ore body 1 contacts the overburden 2, they are assembled into a common explosive network of terminal wires and waveguides 7, programming electric detonators with electronic programmable deceleration, then initiating a common explosive network, where explosive charges 4 are initially initiated in overburden 2, and after the formation of breakup 8 (Fig. 3), programmed electric detonators are initiated with elect Ronal programmable deceleration in charges on ore body 1.

The implementation of the proposed method is carried out when using electric detonators with electronic programmed slowdown in intermediate detonators 5 along the ore body 1 and their initiation from 2 to 3 seconds behind the initiation of waveguides of non-electric initiation systems in intermediate detonators 5 along the overburden 2.

Blasting explosive charges 4 over overburden 2 ensures the subsequent blasting of explosive charges 4 in ore body 1 in a compressed environment with breakup 8, which keeps ore body 1 within its geological location, ensures its high-quality fragmentation due to the retention of explosion products by the formed breakup, ensures subsequent selective extraction by excavator mining by minimizing the mixing of the ore body and overburden in the breakup.

The method is illustrated by the following example. The proposed method was simulated in specialized software and illustrated (Fig. 3 - Fig. 7). Model of the exploded block before the explosion (Fig. 4). As a result of the use of advanced blasting of the overburden rocks, the mixing of the overburden with the ore body is minimized (Fig. 5). As a result of the subsequent blasting of the ore body in the compressed medium (Fig. 6 - Fig. 7), a high degree of crushing is achieved, which is expressed in a low percentage of oversized material, the scattering of individual pieces of the exploded ore body is excluded, and the effect of the air shock wave is reduced.

Thus, the technology of explosive preparation for the excavation of the massif, which includes the occurrence of the overburden and the ore body, with the advance blasting of the overburden, and then the ore body, makes it possible to reduce losses and dilution during subsequent excavator mining of the blasted massif, increase the completeness and quality of mined ores, reduce a dangerous zone due to the scattering of pieces of rock mass and the action of an air shock wave.

Claims (1)

The method of blasting in open pit mines, including the drilling of descending wells, their charging with borehole explosive charges, the lower and upper parts of the charges are dispersed by the rock inert gap, then the wells are stemmed and the charges are initiated, the charges are initiated with advanced short-delayed blasting of the upper part of the charges relative to their lower part , characterized in that blast holes are drilled to the design depth along alternating layers of overburden and ore body with the placement of charges with intermediate detonators equipped with electric detonators with electronic programmable delay in the charge over the ore body and a non-electric initiation system in the charge over the overburden, and the charges are dispersed by the face material until the ore body contacts the overburden, and electric detonators with electronic programmable retardation are programmed in such a way that the initiation of the disperse Some of the charges passed through the ore body after the initiation of some of the charges along the overburden.

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