RU2260770C1 - Method of blasting - Google Patents

Abstract

FIELD: blasting.

SUBSTANCE: method comprises making well charge of individual members of the blasting agents that receive one or several strikers. The members are separated with spaces filled with a liquid with a density of 800-1400 kg/m₃. The strikers are actuated so that the detonation of blasting agent is completed simultaneously in the bulk. The height of the active section of the charge of blasting agent interposed between the boundaries of the liquid and location of the striker are calculated from the formula proposed.

EFFECT: enhanced efficiency.

7 cl, 3 dwg

Description

The invention relates to a method for blasting downhole charges and can be used in the mining industry for breaking rocks.

One of the main directions in the field of rock destruction is the development of new designs of borehole explosive charges, providing increased explosion efficiency. Due to changes in the internal gas dynamics of expanding explosion products, it is possible to change the impulse of the explosion products and its duration on the borehole walls and thereby control the intensity of rock crushing.

One of these areas is the formation of charges with axial and radial air or water gaps (1-4). In known methods for forming a downhole charge, water gaps are located in the upper part of the charge under the bottom of an inert material (5) or in the lower part of the charge (6). With the simultaneous initiation of parts of a charge of different heights, the charge explodes in parts in a cascade, which allows the rock mass to be repeatedly loaded with explosion energy, but at the same time detonation products interact, differing in mass, speed, energy supply, which reduces the efficiency of the explosion.

The closest known technical solutions is the method of drilling and blasting, which includes forming a borehole charge by placing explosives in the hole in separate sections separated by inert intervals, installing one or more fighters and initiating means, jamming the upper part of the well with inert material and initiating this inertial intervals taken air gaps and gaps from the material of the bottom hole; after the initiation of the detonating cord, detonation of sections of the explosive charge occurs with a time delay (7), adopted by the authors as a prototype. The disadvantage of the prototype method is the limited use of the method, since the formation of charges with air gaps is possible only in dry wells; insufficient ratio. the effect of the explosion due to the difference in completion of the detonation of individual sections of the charge.

An object of the invention is to increase the technical and economic efficiency of blasting by controlling the process of the impact of the explosion products in sections of the borehole charge with inert intervals on the destructible rock mass, increasing the efficiency of the explosion and reducing environmental pollution, expanding the use of borehole charges with inert intervals.

The technical problem was solved by the development of a method of conducting blasting operations, including the formation of a borehole charge from separate sections of explosive separated by inert gaps, the installation of one or more fighters, means of initiation, jamming from an inert material in each of the sections of the explosive charge, and initiation, in which they initiate fighters in such a way that the detonation of explosive in all sections of the charge is completed simultaneously, and inert spaces are made of liquid ty with a density of 800-1400 kg / m ³ , setting the height of the active section of the explosive charge (N _BB ), located between the explosive - liquid gap interface and the installation center of the nearest fighter, the height of the liquid gaps (N _W ) between the sections of the explosive substances calculated by the formula:

and the heights of the liquid gaps located at the bottom of the well and under the bottomhole are calculated by the formula:

Where:

- k _g - coefficient taking into account the influence of rock properties on the effectiveness of explosive destruction;

- N _vv1 , N _vv2 - the heights of the active sections of the explosive charge adjacent to the liquid gap, m;

- N _BB - the height of the active section of the explosive charge adjacent to the liquid gap at the bottom of the well or stemming, m;

- ρ _BB1, ρ _BB2, ρ _cc - density explosives charge active portions adjacent to the fluid gap, kg / m ^3;

- ρ _W - the density of the liquid gap, kg / m ³ ;

- D _BB1, D _BB2, D _cc, D _w - detonation velocity explosive charge of active sites and the speed of sound in the liquid, m / s.

The liquid gaps can be made of various liquids of different densities - water, or aqueous or water-glycol solutions of an inorganic oxidizer, and / or urea, and / or flame-retardant salts, or a water-oil emulsion of the first or second kind. Aqueous or aqueous glycol solutions can be thickened with sodium salt of carboxymethyl cellulose or carboxymethyl starch, or polyacrylamide, or guargam, or liquid glass. The regulation of the density of liquid gaps, consisting of thickened aqueous or water-glycol solutions of inorganic oxidizing agents or water-in-oil emulsions, can be carried out by adding gasifying additives, for example sodium nitrite, or microspheres, or expanded perlite sand. A water-in-oil emulsion is made on the basis of water, a liquid oil product, an inorganic oxidizing agent and an emulsifier. Ammonium nitrate or a mixture of ammonium nitrate with sodium, or potassium, or calcium nitrate is used as an inorganic oxidizing agent.

The numerical value of the coefficient k _g varies depending on the properties of rocks in the range from 0.07 to 0.25 and is established by the results of experimental explosions.

Schemes of borehole charges with liquid gaps shown in figures 1, 2, 3.

Figure 1 - borehole charge with two liquid gaps: one between the sections of the explosive charge, the second under the clogging.

Figure 2 - borehole charge in an airtight polymer sleeve with two liquid gaps: one between the sections of the explosive charge, the second at the bottom of the well.

Figure 3 - borehole explosive charge with two liquid gaps located between the sections of the explosive charge of different component composition.

Designations: 1 - liquid gap; 2 - section of the explosive charge; 3 - active area of the explosive charge; 4 - action movie; 5 - stemming; 6 - well, 7 - explosive-liquid interface, 8 - action center installation center, 9 - polymer sleeve.

N _1zh , N _2zh - the height of the liquid spaces, m;

N _vv1 , N _vv2 - the height of the active sections of the explosive charge, m

The arrows show the direction of propagation of the shock waves of the detonation products of the active sections of the explosive charge acting on the liquid gap after the action of the fighter.

The initiation is carried out in such a way that the detonation of all sections of the explosive charge is completed simultaneously.

The heights of the liquid gaps are calculated according to the following scheme: according to the design of the explosion, the type of industrial explosive is selected (detonation speed, charge density), the heights of the active sections of the charge, the location of the liquid gaps, the number and location of the fighters are set, the coefficient k _{g is} determined by experimental explosions . Knowing the detonation velocity and the explosive density of the active portion of the charge, the density of the liquid in the liquid gap, the speed of sound in the liquid, the location of the liquid gaps (at the bottom, at the bottom of the well, between the sections of the explosive charge), the coefficient k _g is set by the heights of the active sections of the explosive charge , according to the proposed formulas, the heights of each liquid gap are calculated.

The downhole charge is formed in the process of separate loading of wells. Liquid gaps are performed in various ways, for example, in sealed (polymer) shells of the appropriate diameter, which are lowered into the well in the required sequence during the loading of the wells. The formation of a borehole charge with liquid gaps can be carried out both directly in the wells and in sealed polymer sleeves lowered into the wells. The charge detonation is excited by fighters from electric detonators, or non-electric detonators, or by a detonating cord, or other means of initiation.

When rock is destroyed by a charge explosion with liquid gaps, the main carriers of energy acting on the walls of the well are the shock wave created by the explosion products and hydraulic flow. With the simultaneous completion of the detonation of all sections of the charge, the shock waves from the explosion products simultaneously begin to act in the axial direction of the charge on the explosive – liquid interface and in the radial direction on the borehole walls. When shock waves are reflected from the interfaces between the fluid, the bottom hole, the bottom of the well, the meeting planes of the shock waves, and the walls of the well, compression waves form from each of the planes, followed by rarefaction waves, cavitation areas at each of these planes. At the junction of the interaction of rarefaction waves in the axial and radial directions, additional cavitation regions are formed that limit the fluid movement in the axial direction. The rarefaction waves from the side walls of the borehole attenuate the incident shock wave along the borehole axis. The presence of lateral cavitation areas leads to the formation of intense rarefaction waves, which also attenuate the shock wave that occurs after closing the cavitation area at the bottom of the well.

The hydroflow from the liquid gap is created due to the shock wave of detonation products of only that section of the explosive charge, which is located between the interface of the explosive with the liquid gap and the nearest fighter center, called the active section of the explosive charge. If several fighters are installed in the explosive section, then the shock waves of detonation products from the operation of the fighters located inside the explosive charge section interact with each other without affecting the hydraulic flow of the liquid gap. Due to the counter-directed shock waves under the influence of the pressure of the detonation products of the active section of the explosive charge, the liquid gap instantly compresses while increasing the density and temperature of the liquid. As a result of this, the fluid passes into a vapor-gas state (vapor-gas) and, expanding, acts by its partial pressure on the adjacent walls of the well. At the same time, additional compression and rarefaction waves from the side walls of the well are formed in the places where the hydroflow (steam and gas) acts, which leads to a decrease in the pressure of the explosion products, a decrease in the acceleration of the fluid in the axial direction, an increase in the fraction of the explosion energy, which goes to the useful work of destroying the rock mass, strengthening the effect on the path of the detonation products of explosives and dusty crushed rock from the well.

Combined gas, acting on the side walls of the well with its high partial pressure, penetrates into the cracks of the rock mass and due to the effect of wedging provides a more intense crushing of rock.

Due to the energy of shock waves, rarefaction and compression, cavitation areas, the explosive products are repeatedly exposed to the rock mass to be destroyed, the time of their active impact until the well is depressurized, which increases the efficiency of rock crushing. In the plane of collision of hydroshock waves with an obstacle, the effect of a sudden stop of the fluid flow during a short period of time occurring under conditions limited by solid (rigid) walls of the well arises, which leads to a hydraulic shock accompanied by a sharp increase in pressure in the fluid and its impact on the rock mass rock surrounding the wall of the well. Calculations show that the pressure of a hydraulic shock of a fluid transmitted to a rock is directly proportional to the density of the undisturbed fluid and the square of the speed of sound propagation in it. Active regulation of the pressure and kinetic energy of the hydraulic shock is carried out through the use of liquid in the intervals between explosive charges with different densities and sound growth rates in it.

Examples of the invention (based on figures 1, 2, 3).

Depending on the geological conditions and requirements for the exploded rock, the types of explosives, the depth of the wells are selected, a combined charge of explosive and liquid gaps is designed with the installation of fighters, upon initiation of which the detonation of all sections of the explosive is completed at the same time, setting the height of one of the active sections charge, heights of all liquid spaces are calculated.

Figure 1 - downhole charge is made with two fluid gaps:

one (H _1g ) - between sections of explosives of the same composition (density and detonation velocity of explosives of active sections of the charge are equal); the second (H _2zh ) - under the bottomhole; in each section of the charge, one fighter is installed (the heights of the active sections of the charge are equal, because they are made of the same composition). Explosive - granulotol GOST 25857-83 with a detonation speed D _BB1 = 6000 m / s and a density ρ _BB1 = 950 kg / m ³ , the height of the active section H _BB1 = 2 m; liquid gaps - a thickened solution of ammonium nitrate, decompressed with microspheres, density ρ _W = 1200 kg / m, sound speed D _W = 1500 m / s; coefficient k _g = 0.15.

According to the invention, the height of the liquid gap (H _1zh ), located between the sections of the explosive charge, is calculated by the formula 1: N _W = k _g [N _BB1 (ρ _BB1 D _BB1 ) / (ρ _W D _W ) + H _BB2 (ρ _BB2 D _BB2 ) / (ρ _W D _W )], where H _BB2 = H _BB1 , ρ _BB2 = ρ _BB1 , D _BB2 = D _BB1 ; _1g H = 0.15 * [2 * (950 * 6000/1200 * 1500) + 2 * (950 * 6000/1200 * 1500) ] = 1.9 m, and the height of the fluid gap H _2g located under tamping calculated 2 according to the formula: H _w = k _r [H _cc (ρ _{cc cc} d) / (ρ _x d _x)], where H = H _{cc BB1,} ρ = ρ _{cc BB1,} d = d _{BB1 cc;} H _2zh = 0.15 * [2 * (950 * 6000/1200 * 1500)] = 0.95 m.

Figure 2 - downhole charge is made with two fluid gaps:

one (H _2g ) - between the sections of the explosive charge of the same composition (the density and detonation velocity of explosives of the active sections of the charge are equal); the second (H _1zh ) - at the bottom of the well; in each section, one fighter is installed (the heights of the active sections of the charge are equal, because they are made of the same composition). The downhole charge is placed in a sealed polymer sleeve to prevent spreading along the side cracks of the well. Explosive - sibirite 2500 RE with a detonation speed D _BB1 = 5500 m / s, density ρ _BB1 = 1250 kg / cm ³ , the height of the active section H _BB1 = 3 m; liquid gaps - water-oil emulsion with a density ρ _W = 1350 kg / cm ³ ; D _W = 1500 m / s, coefficient k _g = 0.10.

According to the invention, the height of the liquid gap H _1zh located between the bottom of the well and the explosive charge section is calculated by formula 2 (analogously to example 1);

H _1zh = 0.10 * [3 * (1250 * _5500/1350 * 1500)] = 1.0 m,

and the height of the liquid gap H _2zh located between the sections of the explosive charge is calculated by the formula 1 (analogously to example 1):

H _2zh = 0.10 * [3 * (1250 * 5500/1350 * 1500) + 3 * (1250 * 5500/1350 * 1500)] = 2.0 m,

Figure 3 - downhole charge is made of three sections of the explosive charge with two liquid gaps located between the sections of the explosive charge of different component composition, differing in density and detonation speed. In the lower and middle sections of the charge made of granulotol GOST 25857-83 with a detonation speed D _BB1 = 6000 m / s and a density ρ _BB1 = 950 kg / m ³ , the adopted height of the active section H _BB1 = 2 m installed one fighter (height active sites adjacent to the lower liquid gap are equal). The upper portion of the charge is made of 79/21 grammonite GOST 21988-76 with a detonation speed D _BB2 = 3000 m / s, density ρ _BB2 = 900 m / s, height of the active portion of the charge H _BB2 = 1 m (in order to ensure the same detonation completion time areas of explosive charge with different detonation speeds, the heights of the active sections of the charge adjacent to the upper liquid gap are different - they are directly proportional to the detonation velocities of explosives). Liquid gaps - an aqueous urea solution with a density ρ _W = 1150 kg / cm ³ , D _W = 1500 m / s. Coefficient k _g = 0.15.

According to the invention the height of the lower liquid gap H _1g disposed between portions of the charge of of granulated calculated by the formula 1: H _1g = k _r [H _BB1 (ρ _BB1 D _BB1) / (ρ _w D _w) + H _BB2 (ρ _BB2 D _cc2 ) / (ρ _x D _g )], where H _cc2 = H _cc1 , ρ _cc2 = ρ _cc1 , D _cc2 = D _cc1 ; H _1zh = 0.15 * [2 * (950 * _6000/1150 * 1500) + 2 * (950 * 6000/1150 * 1500)] = 2.0 m, and the height of the upper liquid gap H _2zh located between the charge sections from granulotol and grammonite 79/21, calculated by the formula 1:

H _2zh = 0.15 * [2 * (950 * 6000/1150 * 1500) + 1 * (900 * 3000/1150 * 1500)] = 1.3 m.

When using inorganic oxidizing agents, urea, water-in-oil emulsions as liquid gaps in aqueous or water-glycol solutions, the oxidizing agent in their composition is additionally involved in the chemical transformation of the explosive - the oxidizing oxygen interacts with the combustible component of the explosive of the charge sites, and when using a metal-containing explosive in the chemical interaction of the metal, water of the liquid gap, which protrudes em in relation to the metal as an oxidizing agent.

Additionally, through the use of liquid gaps, the effect of dust suppression is realized due to the wetting of the dusty particles of the blasted rock with steam condensate, their coagulation and gravimetric deposition at an earlier stage of expansion of the blasted rock. A dust cloud with a large number of small dusty particles of rock due to their coagulation falls above the blasting site and does not pollute the surrounding area.

In addition, water neutralizes toxic gases generated during the explosion of an explosive with a negative oxygen balance. Nitrogen and carbon oxides interact with water to form a liquid phase, which also precipitates above the explosion site, preventing the spread of toxic gases in the form of acid rain outside the danger zone during the explosion.

When using liquid gaps from aqueous solutions of flame-retardant salts, for example sodium chloride, the safety of work is increased by inhibiting the ignition and combustion of explosion products.

Due to the simultaneous completion of the detonation of each of the sections of the explosive, a counter-directional collision and reflection of the shock waves along the axis of the well from the stemming plane, the bottom of the well or liquid gaps occurs with the maximum possible energy reserve for the explosive used. The primary shock waves of detonation products form secondary shock waves of greater efficiency than that of the prototype. Their energy leads to the expansion of the explosive cavity along the entire height of the column of the borehole charge at the same time, there are no losses on the movement of the lower part of the stemming made of inert material of the stemming, which provides more efficient crushing of the rock.

The technical result of the invention and the advantages of the proposed method of drilling and blasting are:

- increased explosion efficiency due to the formation of cavitation areas in the axial and radial directions, the wedging effect created by the vapor-gas of the fluid gap, the later destruction of wells due to the blocking effect created by the fluid spaces, cavitation zones;

- increasing the uniformity of crushing of rock by reducing the maximum pressure and temperature of the explosion products, increasing the weighted average pressure and time of action of the explosion products on the rock mass, the wedging effect created by the vapor-gas liquid gap;

- improving the environmental cleanliness of drilling and blasting operations by neutralizing toxic gases from explosion products, suppressing dust generated during rock destruction, limiting the size of the dust and gas cloud within the explosion hazard zone;

- expansion of the scope of use - in dry and flooded wells, including blasting operations on sulfide-containing rocks and ores when using aqueous or water-glycol solutions of urea as liquid gaps, blasting hazardous to dust and gas when using water or water -glycol solutions of salt flame arresters as liquid gaps.

The proposed method of drilling and blasting was tested on wells of various diameters and in rocks of various strengths and different chemical composition.

The arrangement of charges with liquid gaps depends on the conditions of the explosion and the requirements for the quality of the detonated mass.

Drilling and blasting operations according to the proposed method allowed to increase the uniformity and intensity of crushing of rock by increasing the yield of conditioned and reducing oversized fractions by 10-15%, to increase the yield of rock mass from 1 pm borehole by 3-5%, to improve the working out of the bottom of the ledge, which allowed to increase the productivity of handling and crushing and screening equipment; improve the environmental situation in the area of the mass explosions, reducing the time of dispersal in the atmosphere of a dust and gas cloud.

Sources of information

1. Downhole charges with air gaps, because of the "Science", Siberian Branch, Novosibirsk, 1774.

2. Patent of Russia №2168700.

3. AS of the USSR No. 1153654.

4. AS of the USSR No. 1170839.

5. Patent of Russia No. 2059565.

6. I.N. Kovtun, V. D. Vorobiev, A. A. Daouetas, B. G. Duganov “The effect of water gaps in borehole charges using igdanite on the quality of limestone crushing”, collection “Blasting” No. 81 / 38.

7. Patent of Russia No. 2112207.

Claims (8)

1. A method of conducting blasting operations, including the formation of a borehole charge by placing explosives in the well in the form of separate sections separated by inert gaps, installing one or more fighters, initiating means, blocking the upper part of the well with inert material in each of the sections of the explosive charge, and initiating , characterized in that the militants initiate in such a way that the detonation of the explosive in all areas of the charge is completed simultaneously, while inert ezhutki made of a liquid with a density of 800-1400 kg / m ^3, wondering height of the active portion of the explosive charge located between the interface explosive - liquid center span and setting the nearest action movie, liquid height spacing (H _w) disposed between portions of the explosive charge substances are calculated by the formula

and the heights of the fluid gaps located at the bottom of the well and under the bottomhole - according to the formula

where H _{BB1, BB2} H, H _cc - the height of the charge of the active sites of the explosive, m; k _g - coefficient taking into account the influence of rock properties on the effectiveness of their explosive destruction; ρ _{BB1, BB2} ρ, ρ _cc - density explosives charge of active sites, kg / m ^3; ρ _W - the density of the liquid gap, kg / m; D _{BB1, BB2} D, D _cc, D _w - detonation velocity explosive charge of active sites and the speed of sound in the liquid, m / s. 2. The method according to claim 1, characterized in that the liquid is taken as water, or aqueous or water-glycol solutions of an inorganic oxidizing agent, or flame-retardant salts, or urea, or water-in-oil emulsions of the first or second kind. 3. The method according to claim 2, characterized in that as an inorganic oxidizing agent of the aqueous or water-glycol solution is taken ammonium nitrate or a mixture thereof with calcium and / or sodium and / or potassium nitrate. 4. The method according to claim 2, characterized in that the water-in-oil emulsion contains water, ammonium nitrate or a mixture thereof with calcium and / or sodium and / or potassium nitrate, a liquid oil product, an emulsifier. 5. The method according to claim 2, characterized in that the aqueous or aqueous glycolic solution of the inorganic oxidizer contains a thickener. 6. The method according to claim 5, characterized in that as the thickener is taken sodium salt of carboxymethyl cellulose or carboxymethyl starch, or polyacrylamide, or guar gum, or water glass. 7. The method according to claim 2, characterized in that the aqueous or water-glycol solution of the inorganic oxidizer and the oil-water emulsion further comprise a gasifying additive, for example sodium nitrite. 8. The method according to claim 2, characterized in that the aqueous or water-glycol solution of the inorganic oxidizer and the water-oil emulsion further comprise microspheres or expanded perlite sand.

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