Extraction of ore using explosion and thermal fragmentation
SUBSTANCE: invention refers to mining, and namely to extraction methods of mineral deposits from ore veins. Drilling of wells located at some distance is performed directly in ore vein. Wells are reamed using thermal fragmentation basically to boundary surfaces between ore vein and environment. Then, in ore vein between thermally reamed wells there drilled is pit for introduction of explosive charge. The latter is blasted in order to destruct the ore between reamed wells. After ore vein section is destructed with guided blast wave, the other well is drilled in ore vein at the specified distance from the previous place of blasting operations and thermally reamed, and the next pit is drilled between them for explosive fragmentation. The process is repeated for as many times as it is required for extraction of the necessary amount of ore from ore vein.
EFFECT: invention allows minimising the ore extraction cost by reducing the ore impoverishment.
12 cl, 2 dwg
The technical field to which the invention relates.
The invention generally relates to a method for extraction of minerals using thermal fragmentation to create a blast of directed action.
Disclosure of inventions
The aim of the present invention is to minimize the cost of extracting the ore by reducing the dilution of the ore.
Thus, according to the basic aspect, a method for extracting ore from ore veins, comprising: a) drilling spaced at wells directly in the ore vein, b) applying thermal crushing, extending the well, essentially, to the boundary surfaces between residential ore and surrounding rock to create adjacent thermally enhanced wells, (C) drilling at least one hole in the ore vein between two adjacent extended wells for laying explosives and d) undermining explosives to fracture the ore between the two advanced wells.
According to an additional aspect, a method for extracting ore from ore veins, having side walls, passing along the axis, including the creation of two located at a distance from each other in the axial direction of the zones of weakening along the ore veins, providing less resistance to pressure than the side walls and, in this case, at least one of the zones of attenuation obtained using thermal crushing, drilling out the hole in the ore vein between the zones of weakening, a bookmark, an explosive charge in the borehole, undermining the explosive charge to create the explosion sent to the zone of attenuation, where the resistance is lower.
Brief description of drawings
Figure 1 is a side view of the underground ore veins, passing between two cars workings along the direction of stretch of the ore veins and provide access to the ore vein.
Figure 2 is a top view of the ore veins, shown in figure 1.
Description of the preferred embodiments of the invention
Figure 1 shows an underground ore body 10 or ore vein that runs between the two horizontal mount 12 and 14, with access from the ground surface through an inclined ramp or vertical development, known as the shaft (not shown). As is known in the prior art, the mine is equipped with lifts, which workers, mechanisms and breed can access the galleries or observation wells 12 and 14. Generation 12 and 14 represent the tunnels, built in the rock, the size and shape which allow the extraction of the ore body 10. Each generation produces a current horizon, passing through the ore is eaten. Current horizons can, for example, be spaced vertically at 18 m (59 ft).
As shown in figures 1 and 2, the well 16 (figures 1 and 2 shows only two) drilled at equal intervals along the ore veins 10, each wellbore passes vertically through the ore vein 10 from the top 12 to generate lower development 14. The diameter of these wells typically is about 6 inches (15.2 cm). The diameter of the wells 16 is not critical, but it is preferable to maintain a minimum for minimizing the cost and time of drilling. The diameter should be sufficient to allow for expansion of the borehole thermal fragmentation. Each of the wells 16 may be drilled at half the distance from the top 12 to generate lower production 14 in order to limit the curvature of the borehole. It is clear that wells 16 can be drilled completely from the top 12 to generate lower production 14. As will be seen below, the distance between adjacent wells 16 is chosen to provide enough enclosed space expansion or space, limiting the effect of the explosion so that the ore body between adjacent wells could be destroyed by the explosion with minimal dilution of the ore in the surrounding empty rock. Well 16 is used to further restrict the action of the explosion of the boundary on what arnosti ore veins 10, minimizing, thus, the dilution. Satisfactory results have been achieved at a distance of 6 m between the centers of two consecutive holes.
Each of the drilled wells 16 thermally expand in the manner described in U.S. patent 6,913,320, issued July 5, 2005, the content of which is incorporated here by reference. In particular, each hole 16 extends through the lower burner (figure 1) into the well, its ignition and then gradually rises, until the well will not extend fully from the bottomhole to the wellhead end. Tube P set on hole 16 for its isolation and ensuring an increase in temperature in the well. The heat produced by the burner, increases the temperature in the borehole up to 1800°C. This creates a thermal stress-cracking ore. Simply put, the splitting is a form of cracking caused by the uneven expansion of mineral crystals, overcoming intermolecular coupling. Destroyed or fragmented material formed by this process has a size in the range from fines of up to 4cm (1.6 inches). The tube is removed, and destroyed material Recuperat any suitable way. Wells 16 typically extend to the side wall of the ore veins (for example, the boundary surfaces between the ore body and the surrounding waste rock for the building thermally expanded bore 17, as schematically shown by the dashed lines in figure 2. For example, the distance between the wells 16 can be selected so as to leave about 1 m (3.28 ft) ore between two adjacent extended wells 17 for ore veins, having a width in the range from about 13 inches (33 cm) to about 15 inches (38,1 cm). The distance between adjacent wells is not only a function of the width of the ore veins, but also explosives, which should be used for splitting ore between such extended debilitating wells. As mentioned above, satisfactory results are achieved at a distance of 6 m (19,69 ft) between the centers of adjacent shafts 16 wells.
After the first two wells drilled thermally expanded and emptied, as described above, at least one hole 18 vibereview through the ore vein 10 between two adjacent extended wells 17, as shown in figures 1 and 2. If vibereview only one hole 18, it is usually located in the middle between the advanced wells 17. Each hole 18 is typically located at a distance of 80 cm (31,5 inches) from the periphery adjacent the extended bore 17. The 18 hole can be drilled at half the distance from the top generation 12, the other half vibereview from lower production 14. Alternatively, the hole can be completely drilled from the top exp is processing 12. The diameter of the explosive in the borehole 18 typically has a value in the range 21/2 inches (6.4 cm). It is clear that the diameter of the hole may vary depending on the type of explosive used in it.
Selected explosive charge placed into the hole 18 and then to undermine the destruction of the ore is between two advanced wells 17. As shown by the arrows 20 in figure 2, the effect of the explosion, essentially limited to the boundary surfaces of the ore veins between 10 advanced wells 17. When the explosive charge undermine, a powerful blast wave operates essentially in all directions, but most movement occurs along the line of least resistance or the lowest retention. Advanced borehole 17 provide areas of weakness with less resistance than the side walls of the ore veins. The propagation of the blast wave, therefore, should be directed to the advanced wells 17 in the ore vein 10 and not to the surrounding empty breed with more resistance, thereby minimizing dilution. When creating such wells on opposite sides of the hole, the effect of the explosion may be limited to a direction essentially along the longitudinal axis of the ore veins. In other words, enlarged bore 17 set line of propagation of the shock wave.
After RA the violations section of the ore veins aimed blast, as described above, another well wyborowa in the ore vein 10 at a specified distance from the previous blasting site. Drilled wellbore and then expand by thermal fragmentation described above, and wyborowa second hole in the ore vein in the intermediate point between the place of previous blasting and a new, expanded well. Then in the hole lay the explosive charge, which is then undermined for splitting ore between the location of the previous blasting and a new, expanded well. Again there is a propagation of the blast wave where there is the least resistance, in other words, along a line passing between the first place of blasting and a new, expanded well. This process is repeated as many times as necessary to retrieve the required quantity of ore from the ore veins. It is also clear that all of the wells and bore-holes you drill, and then to produce thermal fragmentation wells. In the ore vein can be made consistent undermining. Also offered other sequence of drilling and blasting.
1. The method of extraction of the ore from the ore veins, including:
a) drilling spaced at wells directly in the ore vein, b) applying thermal crushing, extending the well, in which usesto, to the boundary surfaces between residential ore and surrounding rock to create adjacent thermally enhanced wells, (C) drilling at least one hole in the ore vein between two adjacent extended wells for laying explosives, and (d) undermining explosives to fracture the ore between the two advanced wells.
2. The method according to claim 1, in which the distance between the centers of adjacent boreholes is about 6 m and less.
3. The method according to claim 2, in which at least one hole vibereview at a distance of about 80 cm or more from adjacent the periphery of the expanded hole.
4. The method according to claim 1, comprising placing a tube in the downhole end of each located at a distance well before performing thermal crushing.
5. The method according to claim 4, including the removal of the tube upon completion of thermal crushing and recovery of fragmented ore to perform step (d).
6. The method according to claim 4, in which step b) includes lowering the burner in well before they downhole end and its gradual ascent to the mouth for a gradual expansion of the borehole from the bottom to the mouth.
7. The method of extraction of the ore from the ore veins, having side walls, passing along the axis, including the creation of two located at a distance from each other in the axial direction of the zones of weakening along the ore veins, providing ensee resistance to pressure, than the side walls, with at least one of the zones of attenuation obtained using thermal crushing, drilling out the hole in the ore vein between the zones of weakening, a bookmark, an explosive charge in the borehole, undermining the explosive charge to create the explosion sent to the zone of attenuation, where the resistance is lower.
8. The method according to claim 7, in which the step of creating two located at a distance in the axial direction of the zones of weakening includes: drill out the two located at a distance of wells in the ore vein between the side walls and the use of thermal fragmentation to extend two spaced at wells to the side walls.
9. The method of claim 8, wherein the bore extends from the bottom to the mouth.
10. The method according to claim 8, in which thermal fragmentation involves the placement of tubes located at a distance of wells and ignition burners in them.
11. The method according to claim 8, containing the removal of tubes from wells on the completion of their expansion by thermal crushing and recovery of fragmented ore to detonate the explosive charge.
12. The method according to claim 8, in which the centers are located at a distance of wells located at a distance of about 6 m or less to leave the area between the two spaced wells, with the specified teaching the current after the expansion of wells to the walls of the ore veins has a length of about 1 m
SUBSTANCE: method includes calculation of parameters of stress waves regarding the deflexion of detonation wave and energy dissipation. Rock stress is determined after detonation wave deflexion on the base of the laws of breakdown of an arbitrary discontinuity of data by the properties of explosive substances and impact adiabats of rock material. Then Cauchy problem is solved by the data about stress waves' parameters at random distances that allows determining these parameters at all further distances. It is taken into consideration that the rock is first dynamically loaded and then statically unloaded. Entropy change takes place only at impact wave front. Thus there is the difference between the energies of loading and unloading that is the energy of dissipation itself. Considering dissipation energy there calculated are the stresses obtained in massive at various distances from the charge.
EFFECT: method allows reducing the volume of small fractions and improving ecological indices of blasting activities.
1 tbl, 1 dwg
SUBSTANCE: method involves drilling of blast holes with increased subdrilled area, their charging with an air cushion arranged in the above subdrilled area, and explosion of mine rocks. Air cushion with length of 6-10 diameters of the well is created below actual level of bench bottom by 2-3 diameters of the well. Additional charge with length of 10-20 diameters of the well is arranged under the cushion.
EFFECT: improving the efficiency of charges.
SUBSTANCE: method includes drilling vertical main wells, definition of a contour in plan and soil elevations of solid inclusions along the depth of the main wells, drilling additional vertical wells inside the contour of inclusions, charging main and additional wells with explosive charges, with placement of explosive charges in additional wells inside their inclusions and their blasting. Selection of explosive charge parameters for charging additional wells is carried out by the value of product of explosive detonation speed and explosive charge diameter defined from the ratio.
EFFECT: higher efficiency of solid inclusions grinding.
2 cl, 2 dwg
SUBSTANCE: block to be exploded is drilled around the perimeter of its connection to rock mass by means of a row of wells in 3-4 metres. At that, during preparation for drilling and explosion loosening the well rocks in the row are drilled to the depth below the coal formation through the distance excluding the formation destruction during explosion of row by means of base charge.
EFFECT: reducing the cost of rock mass to be exploded owing to using explosives non-resistant to water as a result of drying of the block to be exploded.
SUBSTANCE: method of blast-hole drilling ensuring preset extent of blast rock grinding includes drilling of explosive wells at the distance between them, depending on detonating characteristics of explosives, physical and technical properties of a rock massif, parameters of its cracking, their charging and explosion. Explosive wells are charged with explosives with specific consumption per m3 of blast rock in amount determined with account of explosive energy losses as charge explosion products expand in a well volume occupied with the charge, and also with account of losses related to the extent of the specific explosive detonation completeness in the well of the specific diameter, which are introduced into a calculation expression for a coefficient of relative operability of the applied explosive.
EFFECT: reduced volume of drilling works in drilling of explosive wells, which results in higher efficiency and reduced cost of blast-hole drilling.
SUBSTANCE: in the method to form charges in drowned wells, including drilling of wells, their filling with explosives and a plug from inertial materials, a multicharge is formed in wells filled with water, made of two different types of hose explosive charges. The main hose explosive charge with detonation speed corresponding to the speed of stress wave propagation in surrounding rock and weight of 75…80% from total mass of the multicharge is placed vertically along the well axis. The second hose explosive charge with high speed of detonation exceeding the speed of stress wave propagation in a rock massif and weight of 20…25% from the total mass of the multicharge, is placed along the spiral around the first hose charge, with a pitch of one turn along the vertical line equal to two well diameters. Linear initiation of the explosive multicharge is carried out simultaneously along the entire length of the well with a detonating chord with a charge of 40 g/m.
EFFECT: amplified amplitude of a voltage pulse and intensity of rocks grinding, which as a whole increases efficiency of drilling and blasting works with reduction of hazardous effect of explosion to environment.
5 cl, 1 dwg
SUBSTANCE: during performance of drilling and blasting works in the lower part of each explosive well a bottom charge is arranged, on the outer surface of which there is a circular cumulative groove arranged, the top of which lies in the horizontal plane, which separates the volume of the bottom charge in two and matches the plane of a working site of an open pit ledge or a bottom of an underground stope. The value of well subgrade drilling is accepted as equal to the half of the cumulative groove base width.
EFFECT: reduced drilling flow due to reduction of subgrade drilling and higher quality of arrangement of a working site of open pit ledges and a bottom of stopes at underground mining works.
SUBSTANCE: inclusions may be represented by layers of hard rocks, various lenses and other inclusions, such as permafrost (eternal frost) in less hard enclosing rocks. Explosive charges in additional shortened wells are placed at the level or below the soil of hard inclusions and are exploded with moderation relative to charges in the main wells. The proposed invention makes it possible to execute efficient grinding of solid inclusions that are previously softened by explosion of charges in the main wells, due to dynamic effect of explosive gases from explosion of charges in additional wells at the lower part of inclusions.
EFFECT: higher efficiency of grinding of various solid inclusions available in the upper and middle part of the ledge and arranged in less hard enclosing rocks.
2 cl, 2 dwg
FIELD: oil and gas industry.
SUBSTANCE: method for forming hose charge in wells involves well drilling, arrangement of hose charge in it and stemming by means of inert materials. At that, hose charge is made in the form of a spiral wound on thin-wall perforated plastic pipe, with winding pitch equal to 4.0…5.0 diameters of hose charge. Hose charge and detonating cord is attached to thin-wall perforated plastic pipe. After the assembled structure is arranged in the well, cavity of the pipe and gaps between coils of hose charge are filled with water to the level of hose charge and the well is stemmed with inert materials.
EFFECT: reducing the specific flow of an explosive, increasing the crushing efficiency of rock masses, and reducing the dust loading of ambient air.
SUBSTANCE: method comprises shot hole or bore-hole drilling, loading them with explosive material so that the bottom part of the shot hole the explosive material density or energy concentration would exceed the one in the wellhead of the shot hole. The mass of explosive material charge in the bottom part of the shot hole is calculated mathematically, depending on the line of least resistance value, the diameter of explosive material charge, fissure parameters and physical and technical mountain mass parameters, the rock pressure and detonation velocity of the explosive material.
EFFECT: enhanced efficiency and safety of drilling and blasting operations alongside with ore beneficiation efficiency.
1 dwg, 1 dwg
SUBSTANCE: method includes iron ore deposit development by wide cuts for passing of which there used are heading machines with executing element of selective action. The boundaries of iron ores separation with different ferrum content are defined within the area of wide cuts face. At cuts passing first there performed is the breaking of ore with ferrum content exceeding the required level, after that there performed is the breaking of ore with ferrum content not exceeding the required level. Note that the breaking of ore with ferrum content exceeding the required level is done with higher cutting speed and lower speed of feeding the executing element of machine to the face, than at breaking of ore with ferrum content not exceeding the required level. Ore mass broken by machine is transported to the screen, where small fractions of ore with ferrum content exceeding the required level are separated.
EFFECT: increase of reliability of creating iron ore flows with required level of ferrum content.
SUBSTANCE: method involves central and flank preparatory mining operations; their fastening by roof bolting, control of formation pressure, stowing of the worked-out area, transportation of broken ore after preparatory mining operations using self-propelled equipment and implementation of ventilation, supply of stowing mixture, water drainage, loading and transportation of rock mass, as well as additional processes of mining practice are performed on one and the same preparatory horizon, which was passed along ore body and supported in natural massif. Peripheral part of workings is pre-formed by passing through rooms adjacent to development working, installation of metal fittings in them and filling by means of consolidating stowing; after that, development working is performed along the ore under protection of the already formed support in the form of stowing reinforced-concrete solid mass.
EFFECT: increasing the development efficiency.
SUBSTANCE: development is performed during winter period. First, vertical through wells with diameter of 0.5-0.6 m are drilled from surface above developed mine field, through which ice-water mixture is supplied; ratio of solid phase to liquid phase is 1:3 by volume. Filling mass is erected layer by layer; at that, each layer is frozen with forced blowing using cold atmospheric air from blowdown fan. Thickness of a single layer |Nlayer| is determined from the following ratio: Nlayer=1.5|tamb.|-20, cm, where: 1.5 and 20 - constant coefficients; |tamb| - absolute monthly average ambient air temperature of months during winter period, °C.
EFFECT: invention allows reducing the time required for stowing operations and improving the stowing quality.
SUBSTANCE: method includes tunnelling of development and face-entry mines, arrangement of stope drifts along ore body soil, formation of a free process space along the front of stoped excavation, tunnelling of drifts in each even layer of the ore, its excavation in strips, upward cutting by layers in the strip, hole drilling and breaking of another layers of ore from the specified space after breaking, discharge of broken ore and backfilling of developed space with a hardening mix. Drifts in each even layer of ore pass as advance layer slopes transversely to stretching front of stoped excavation. Side loading drives are additionally arranged on soil of ore body. The free process space is formed along the entire width of the strip. Another layers of ore are drilled from previously prepared surface of shrinked ore material (SOM). Restoration of the specified space contour after breaking of another layer is carried out by partial loading and planning of broken ore by mobile equipment with driving via mentioned slopes. Massive discharge of the entire volume of shrinked ore material is carried out after breaking of the last layer of ore via side loading drives and a stope drift of the adjacent strip. Backfilling of the mined space is carried out after its isolation with links in one stage with a full-strength hardening mix for the total height of broken ore layers.
EFFECT: improved efficiency of production due to simplified technology, reduced number of stages in works performance and lower costs for filling of the mined space by reduction of consumption of high-grade filling and reduced duration of preparation and finalisation operations.
2 cl, 7 dwg
SUBSTANCE: when developing thick steep deposits of unstable ores, at first the ore body is divided into levels. Then level and section mines are driven, the ore body is mined downstream filling the mined space with hardening materials. The level is divided into two sublevels. The upper sublevel is divided into layers. The extraction within the layers is carried out with horizontal or drift stopes with complete filling of the mined space produced in process of stopes driving with hardening materials. Lower sublevel reserves are extracted under the filling mass arranged when mining the upper sublevel. Prior to extraction of lower sublevel resources, a concrete bottom is developed for relief of ore mass that collapsed during mining of the lower sublevel into level transport mines. To extract resources of the lower sublevel, it is divided into blocks. Blocks are mined by uncontrolled caving of ore carried out as a result of base undercutting. Mining of another blocks of the lower sublevel is started after complete filling of the mined space produced during mining of blocks having common boundaries with mined blocks.
EFFECT: improved labour efficiency and safety of mining works.
SUBSTANCE: formation mining method of kimberlite pipe involves mining of ventilation, bottom and sectional gangways, ventilation and filling raises, ore chute, formation mining and stowing operations. At that, each formation is divided in horizontal plane into several sections with equal equivalent roof passage. Sections are mined and stowed subsequently using pneumocylinder support installed in staggered order. Before the stowing material is supplied to the worked-out section of the bed, pneumocylinder support is shifted to one row along the boundary of the next worked-out bed section. Support is isolated from the worked-out section of the bed with installation of the required stowing connection straps. Stowing material is supplied to the worked-out section till complete filling; after that, the next section is worked out using pneumocylinder support in the above sequence.
EFFECT: reducing labour intensity of the operations of the method and increasing the resources development speed.
SUBSTANCE: development method of tube-like thick steep and flat dipping ore bodies involves preparatory and first works, second mining with vertical cuttings along the spread or across the spread by means of drilling method for resources with large-diameter wells, ore output and goaf stowing. At that, width of cuttings is accepted equal to diameter of production well and second working is performed in cuttings in three stages. At the first stage the removed cutting is drilled along its length with transverse rows of vertical blasting wells throughout the height of the mining level. In the middle between the drilled transverse rows of blasting wells there drilled by means of known methods are scavenger wells and ore mass broken during drilling is shrunken owing to its partial drawing. At the second stage of the second mining of the cutting there drawn is ore mass shrunken in scavenger wells with further blasting of transverse rows of vertical wells throughout the height of the mining level and output of ore mass broken by blasting operations. At the third stage there filled is the worked-out area of the cutting with hardening stowing mixture.
EFFECT: higher efficiency of the development, crushing quality of the produced ore and creation of safe conditions for mining activities at high level of their mechanisation.
SUBSTANCE: during cutting of a mine section, drilling rooms are tunnelled in direction of the highest value of the ore body shape complexity module: horizontal ones, if this module has the highest value along the line of the ore body length, and ascending ones, if the complexity module has the highest value along the line of the ore body descent. Section resources mining is carried out in sections along the entire length or height of the breakage section. Each section is broken using blast holes in layers to form an ore bank by explosion delivery. Ore bank compactness is ensured in process of its formation by serial cutting of layers of alternate width in each cut section, and their width increases in direction from the line of the cut section face to the depth of the massif. Thus formed ore bank adjacent to the face of the next mined section is displaced following the front of second mining by alternation of ore mass accumulation cycles in the ore bank and its layerwise removal and discharge from the outer side of the ore bank in respect to the face.
EFFECT: expanded area of application of highly mechanised technologies, increased efficiency of labour and safety of production works.
SUBSTANCE: in method realisation, block resources are developed in sections, size of each in direction of maximum variability of ore body shape is established as permanent and is determined according to process conditions. Ore and rock breaking in a breakage block is carried out by sections in two stages. At the first stage due to grinding and explosion delivery of waste rock cut according to the process conditions to the ore body at a hanging or a lying side, a rock bank is formed as adjacent to the line of the cut section face. Its compactness is ensured by serial cutting of rock layers of alternate width in the cut sections, and their width reduces in direction from the line of the cut section face to the depth of the massif. Thus formed rock bank from ground rock thrown off by explosion is left in the mined space of the breakage block. At the second stage the ore body is broken at the area of its bedding with subsequent discharge of only broken ore from the breakage block.
EFFECT: increased efficiency and safety, higher parameters of complete usage of balance stocks.
1 cl, 5 dwg
SUBSTANCE: method includes driving of mine preparation excavation, development of craters for discharge of caved ore and area of uncontrolled caving cutting with formation of a dome-shaped ore pile. In an ore body there is a central well drilled, and several additional wells are drilled at the distance of hydraulic radius of cutting. Then via each well, surfaces of ore pile and vault roof are scanned along concentric circumferences with specified pitches along a horizontal and a vertical lines with a light beam from a laser source arranged in a cavity formed by these surfaces and aligned by an azimuth. Using values of measured and specified parameters, coordinates of contact points are determined, and a spatial form is built for a surface of an ore pile and an uncontrolled caving vault. Information signals are treated with the help of a computer in a processing system.
EFFECT: control signals are generated for a process of ore discharge from craters, besides, a cycle of pile and vault surfaces form control is carried out with the specified frequency.
2 dwg, 1 ex
SUBSTANCE: method includes destruction of rocks at face by impact of power tool and jets of working agent running out under pressure, removal of drilling mud to the well head by working gaseous agent reflected from the face. Face area is influenced with working gas agent under its temperature 700-900°C, agent jet pressure on the face 3-10 kgf/cm2 during 1-2 minutes upon simultaneous appliance of acoustic vibrations from operating agent and drilling unit heads on these jets and creating the conditions for sections change-over on the face; by means of such influence 5-10 mm of rock layer are weakened breaking its thermal and mechanical inertia; cooling agent is supplied to preheated face by short-time pulse during 1-3 sec with pressure 10-70 kgf/cm2 in the form of carbonic acid or mixture of water with carbonic acid, form network of fractures or tiny fractures in this layer, upon impulse action on the face by working gas agent under pressure 50-100 kgf/cm2 and temperature 600-800°C cooling agent residuals are vapourised, destroyed rock is removed from the face, constant upstream of drilling mud to the well head is created, choosing its lifting speed within 20-60 m/sec due to control of quantity from 2 to 9 m3/sec of gas flow supplied from thermo-gas generator to the part of working heads of drilling unit; after that the activities specified are repeated in the same sequence.
EFFECT: increasing effect of the method and efficiency of the drilling unit.