Safety devices and rescue devices (E21F5)

E   Fixed constructions(158841)
E21F5                 Safety devices; rescue devices(3099)
Anti-pyrohenogenic reagent for preventing coal self-ignition in storage and transportation // 2637221
FIELD: chemistry.SUBSTANCE: antipyrogenic reagent comprises a mixture of trichloroethyl phosphate 20.0-30.0 wt % and the rest to 100 wt % of the dust suppressor of potassium salts in the form of a mixture of monoglycolic not more than 5.0%, diglycol 20%, triglycol 20%, tetraglycol 10%, pentaglycol 10% with monoethyl ethers of tri- and tetraethylene glycols of not more than 30.0% in water of not more than 5.0%.EFFECT: lower fire risk, increasing the frequency of use, the possibility of using the composition in the winter due to the low freezing point.1 tbl, 3 ex

Dust suppression method // 2634146
FIELD: mining engineering.SUBSTANCE: invention relates to dust suppression at negative and moderately positive temperatures of air and rock in mine workings and quarries directly at the dust source. The proposed dust suppression method includes supply of compressed air to a nozzle of a snow generator with following direction of snow flame into a dust cloud. In this case, compressed air is preliminarily divided into wet hot and dry cold portions. Wherein, the cold portion is supplied to the nozzle of the snow generator, the generated snow is directed to the upper portion of the dust cloud, and hot portion of compressed air is directed to the lower portion of the dust cloud directly to the dust formation source. At that the flames of the hot air flow opening and the cold snow flow do not intersect.EFFECT: increased suppression reliability of strong dust formation sources.1 dwg
ethod for detecting underground fires // 2631516
FIELD: mining engineering.SUBSTANCE: invention relates to safety field and prevention of endogenous fires during underground mining of coal beds prone to spontaneous combustion. The method for detecting underground fires is proposed, which includes conducting electrical exploration with measurement of specific resistivity, the width of the beds of the geoelectrical section, and the determination of coal temperature t in the area abnormality. The method is carried out from the earth surface, and coal temperature t in the area of abnormality is determined taking into account the electrical exploration of the geoelectrical section and the properties of coal.EFFECT: increased efficiency and accuracy of underground fire sources location, reduced costs for extinguishing fires and improved safety of mining operations.1 dwg
Anti-pyrogenic reagent for storage and transportation of coal // 2625109
FIELD: mining engineering.SUBSTANCE: antipyrogenic reagent for storage and transportation of coal contains chloroparaffin "ХП-470" 20.0-30.0 wt %, dust suppressor of potassium salts as a mixture of mono-, di-, tri-, tetra-, pentaglycols and monoethyl ethers of tri- and tetraethylene glycols - the balance is up to 100%.EFFECT: reagent ensures lowering of fire hazard, increasing the frequency of use, lowering the freezing point.1 tbl, 3 ex
Composition for prevention of coal combustion in storage and transportation // 2623755
FIELD: mining.SUBSTANCE: composition for prevention of coal combustion in storage and transportation contains 5% orthophosphoric acid, alkyltrimethylammonium chloride cationic surfactant, potassium salts dust suppressor as a mixture of mono-, di-, tri-, tetra-, pentaglycols and monoethyl ethers tri - and tetraethylene glycols, with the following proportions of components, wt %: 5% orthophosphoric acid - 76.0-88.0%; alkyltrimethylammonium chloride cationic surfactant - 2.0-4.0%; potassium salts dust suppressor in the form of a mixture of di-, tri-, tetra-, pentaglycols and monoethyl ethers of tri- and tetraethylene glycols - the rest up to 100%.EFFECT: lowering the fire hazard, increasing the frequency of use.1 tbl
ethod of atmospheric open-cast fumes prevention // 2622062
FIELD: mining.SUBSTANCE: method of atmospheric open-cast fumes prevention involves creating barriers in the way of movement of the dust cloud, its localization by placing a shelter in the open-cast working areas. A grid with a mesh size of 50 to 100 mcm and a height H calculated according to the above mathematical expression is set on the windward open-cast side, perpendicular to the movement of the air flow.EFFECT: reduction of dust load on the atmosphere of the open-cast and its location area.2 dwg

Preventive means for the protection of erosionally hazardous dust surfaces in the conditions of low temperatures // 2621333
FIELD: chemistry.SUBSTANCE: preventive tool includes gas oil fractions of thermal degradation processes of petroleum hydrocarbon feedstock processing as a solvent and a heavy oil residue as a thickening additive. The solvent is a mixture of gas oil fractions of catalytic cracking with a boiling range of 200-340°C and 340-470°C in a ratio of 1:1 in an amount of 80-90 wt %. The thickening additive is the cracking residue of the visbreaking process in an amount of 10-20 wt %, preheated to a temperature of 50-70°C.EFFECT: invention makes it possible to improve low-temperature properties, reduce the cost of preventive measures, and expand the raw material base.2 ex

ethod of mineral deposits mine development which are dangerous according to gas dynamic and geodynamic phenomena // 2620687
FIELD: mining.SUBSTANCE: in the face the gas flows are separated from the explosive dust, the isolated production is prepared, isolating it from the worked out area of the face with an abutment with a manhole and a bulging shockproof damper. The nozzle of the suction gas pipe is fixed to the roof at the mine face, and the nozzle of the dust duct is installed in the lower part of the worked out space on its soil. Fans of local ventilation are turned on for the suction from the face, for the suction to the isolated working, where, together with mixing gas flows with mine dust, gas-saturated dust and coal briquettes are produced, mixing the mineral deposits detrital products and surrounding rocks, compacting them with pressure. The strength of the resulting briquettes is increased by the addition of binders, for example petroleum bitumen, and the resulting mixture is extruded through the calibration holes into the briquette container. The briquettes are then dried and sealed.EFFECT: prevention of explosions of gas and mine dust generated during mining operations and excavating by modern high-performance complexes, the use of these gases and dust for the energy-intensive briquettes manufacture and the elimination of emissions of harmful substances into the atmosphere.2 dwg

Radioisotope measuring of dust deposit in mines and device for its implementation // 2618268
FIELD: mining engineering.SUBSTANCE: invention relates to dust control of mining surfaces, industrial facilities in the coal, mining and other industries and agricultural production where explosive dust is present: coal, sulfide, flour, plastic and others. A radioisotope method for measuring dust deposits in the mines, which consists in the use of direct absorption of beta radiation by soft dust deposited on a thin substrate-collector, which is placed on the detector and the source of carbon-14 in the form of a thin tablet is placed on the L-shaped rack above the collector at a certain height from its center. In this, a measurement of the dust sludge masses shall be produced in the following sequence. A thin collector, such as a filter AFA is placed on the detector. The intensity I0 beta-particles flux is measured, passed through the filter, and then the flow rate measurement of beta particles during deposition of dust is made Ii. There is determined a dust mass in mg, deposited at 1 cm2 of a surface, and k shall be determined from the comparison of the surface density σi with the value determined gravimetrically, while the measurement error is calculated. Measurementsσi continuously occur at intervals between the measurements, depending on the sludge accumulation rate, as long as the errorΔσiσ/i reaches a predetermined value. The measurement cycle shall be repeated until the weight of the quantity of dust deposited on the filter reaches a predetermined value. The result shall be represented either on a digital display or by colour signals that indicate the degree of approximation of settled dust mass to the critical value.EFFECT: invention allows to improve the efficiency and safety of the use of radioisotope method for measuring the current mass of the dust sludge and to simplify the design of its implementing device.3 cl, 1 dwg
Coal mine ventilation system and device for methane recovery from mine air (versions) // 2616954
FIELD: mining.SUBSTANCE: ventilation system comprises at least three air ducts, clean air flows through one of the forced draft air ducts, wherein forced draft canopy area considerably exceeds the air duct section. The mine air containing concentrated methane is extracted through the second air duct connected to device for methane recovery from the mine air and mounted at the highest points of the coal heading, wherein the exhaust canopy area considerably exceeds the duct section. The contaminated mine air is extracted through the third air duct, which is mounted at the lowest points of the coal heading. The air ducts spread from the working face to the ground surface. Gasproof partitions are mounted on the ceiling portion along the full length of excavation transversely to the longitudinal direction. Air balloons filled with incombustible gas are attached to the coal heading ceiling with cords, wherein the air balloons are heavier than methane but lighter than the air. Sensors fixing the air balloons height level are mounted at level of gasproof partition lower part, designed to transmit a command for increasing or decreasing the drawing speed of the mine air containing methane and to discharge the clean air. Device for methane recovery from the mine air, flowing from the mine, comprising a sealed tank, air balloons filled with incombustible gas are attached to its ceiling part, wherein the balloons are heavier than methane but lighter than the air. Sensors fixing the air ballons location level are mounted at level of the middle part and higher, designed to transmit a command for increasing or decreasing the drawing speed of methane/air enriched in methane. The air duct feeding the mine air flowing from the mine and comprising a large number of methane is mounted at level of the middle part and lower.EFFECT: prevention of explosions due to accumulation of methane-air mixture under roof with the possibility of subsequent concentration of methane-air mixture for further use.7 cl, 5 dwg

Off-road vehicle // 2613751
FIELD: transportation.SUBSTANCE: invention relates to off-road vehicles using an air cushion, for instance, in open pits after blasting works. Vehicle comprises a body, a bottom, a flexible barrier of the air cushion cavity made along the perimeter of the body bottom, nozzles to supply compressed air, a suction air intake of an air blower, relief pipelines, a cargo container. Besides, outside the perimeter of the flexible barrier of the air cavity, the bottom is equipped with a looped elbow with nozzles to suck in loose material. Besides, the looped elbow by means of relief pipelines is equipped in series both with the cargo container to collect loose material and to clean air from it, and an air intake.EFFECT: invention provides for collection and transportation of dust generating loose material from soil surface.1 dwg

Automatic explosure isolation barrier // 2613393
FIELD: fire safety.SUBSTANCE: an automatic explosure isolation barrier is proposed. It comprises a control unit connected to the dispatcher through a communication line, cylinders filled with extinguishing agent, liquid and inhibitor spraying blocks and sensors. Furthermore the liquid spraying blocks are secured in openings around the perimeter and located in the sequence as follows: the first block for gaseous inhibitor spraying, connected to the cylinders with an inhibitor, and the second block for liquid spraying, connected to both permanently installed and autonomous water supply systems. The control unit is connected with the light and heat sensors and pressure sensor. Furthermore, the control unit and inhibitor cylinders are located in an explosion proof enclosure.EFFECT: increased level of protection during isolation of methane-air mixture and coal powder explosion sequentially using different action barriers.1 dwg

Areal sources dust suppression system // 2608089
FIELD: ecology.SUBSTANCE: invention relates to ambient environment environmental protection devices, particularly, to dust suppression devices, can be used for dust removal, areal dust emission sources irrigation, as well as for supplied from source dusty air dust removal, where use of dust control systems with possibility of large areas processing is required. Areal sources dust suppression system, including vehicle, on which installed aerosol mist-forming gun with guidance device, compressor and pumping stations, water tank, electric current generator, control and monitoring unit, wherein used vehicle is railway platform, moving on railway track along dust-forming array, on railway track opposite to array sections boundaries passive radio frequency tags are arranged, and on platform are installed tags reading device and wireless data transmission wireless device for reception and process monitoring data processing and automatic remote control.EFFECT: use of areal sources dust suppression system allows to completely automate dust suppression process, enable rapid dust elimination, as well as increase transported water margin weight for aerosol gun operation.1 cl, 1 dwg
ethod of protection from rock bumps and sudden emissions // 2599121
FIELD: mining.SUBSTANCE: invention relates to mining industry, particularly to methods of preventing rock bumps and gas-dust emissions. Method involves drilling wells and injection of aqueous solution of an electroconductive fluid into them, for example aqueous solution of calcium chloride, which is preliminarily cooled to negative temperature. Solution concentration is chosen so, that the temperature, to which the solution can be cooled, provides freezing of rocks within the zone of the well thermal influence and creation of continuous zone of melted-frozen medium between the wells.EFFECT: technical result is reduction of labour intensity and higher efficiency of prevention of dynamic phenomena in the rock mass due to differential softening of the rocks layer lying near the mine working.1 cl

ethod for heat and wet treatment of coal massif by surfactants solutions (wetting agents) and device for its implementation // 2599116
FIELD: mining.SUBSTANCE: invention can be used to increase efficiency and create safe and comfortable working conditions during underground and open development of coal massif. Method for heat and wet treatment of coal massif by surfactants solutions - wetting agents includes drilling network of wells, which are combined into a single system. Wells are sealed by hydraulic locks at the inlet, valves - pressure reducing valves or throttles are installed at the outlet. Then the solution is pumped in the wells under pressure, depending on mining and geological properties of the massif, at the concentration of 1-2 CCM, at high temperature in closed cycle to coal saturation with wetting agent. At that, deficiency of wetting agent in the solution, caused by its coal sorption, is filled with the amount determined according to the specified mathematical expression. Wetting agent is delivered in fractures and pores that creates pressure differentials, Amount of sorbed wetting agent is increased by heated solution circulation, micro-cracks are opened, massif is slackened, its filtration ability and delivery of wetting agent in the place of prefracture are increased. Process is controlled according to pressure in the system and to concentration of wetting agent at the well outlet. Optimum temperature of solution supplied into the massif is maintained within the range of 35-40 °C. End of the process is determined according to concentration of wetting agent at the well outlet, which must not be less than 0.5 CCM, or according to abrupt pressure decline between inlet and outlet of liquid in the system of wells.EFFECT: higher efficiency of coal extraction and labour safety due to sorption coal saturation by wetting agent of heated solution under pressure, leading to significant reduction of strength of coal massif at simultaneous connection of dust and coal gas recovery.3 cl, 5 dwg, 1 tbl
Hardening foam material containing coal ash, for preventing coal self-ignition and preparation method thereof // 2588588
FIELD: fire safety.SUBSTANCE: group of inventions relates to curable foam material containing coal ash, for prevention of self-ignition of coal and its production method. Curable foam material containing coal ash, for preventing coal self-ignition contains, wt%: water 40-60, coal ash 100, powdered composition, which releases gas during chemical reaction, 25-40, accelerator 3-5, activator of 2-4, plasticiser 1-2, stabilising foam composition 1, wherein powdered composition, which releases gas during chemical reaction is obtained with following ratio, wt%: calcium sulphate hemihydrate 24-35 and sodium bicarbonate 1-5, which react with formation of inert gas , i.e. gaseous carbon dioxide to form so foamed lime solution; accelerator is obtained with following ratio, wt%: alumina clinker 1-2, sodium carbonate 1 and burnt lime 1-2, wherein alumina clinker consists of following ingredients, wt%: sodium aluminate 94, aluminium oxide 4, calcium aluminosilicate 2; activator is obtained with following ratio, weight parts: magnesium oxide 0.8-1.6 and magnesium chloride 1.2-2.4; plasticiser is obtained with following ratio, wt%: calcium lignosulphonate 0.5-1 and product of naphthalenesulfonate condensation with formaldehyde and 0.5-1, wherein in product of naphthalenesulfonate condensation and formaldehyde content of Na2SO4 is < 3 %; stabilising foam composition is obtained with following ratio, weight parts: butyl ether of ethylene glycol 0.2, nano silicon 0.3 and hydroxyethyl cellulose 0.5; at that time of hardening of said foam material can be adjusted by selecting weight ratios between accelerator, activator and plasticizer. Method of producing curable foam according to claim. 1 includes step 1: addition of 40-60 wt%. water, 0.2 wt%. butyl ether of ethylene glycol, 0.3 wt%. nano silicon and 0.5 wt%. hydroxyethyl cellulose in special vessel for mixing and stirring obtained solution at rate of 3,000±100 rpm by means of mixer for 2 minutes with formation of homogeneous foam solution; step of 2: addition of 100 pts.wt of coal ash, 1-2 WT% of aluminous clinker, 1 wt% sodium carbonate 1-2 weight parts of burnt lime, 0.8-1.6 wt% of magnesium oxide 1.2-2.4 wt% of magnesium chloride, 0.5-1 pts.wt of calcium lignosulphonate and 0.5-1 pts.wt of naphthalenesulfonate condensation product and formaldehyde in mixer for dry mixing, and mixing obtained powder at rate of 3,000±100 rpm for 3 minutes with help of mixer to form mixed powder; stage 3: addition of mixed powder produced in mixer for dry mixing B, in homogeneous foam solution in special vessel for mixing A, and mixture stirring at rate of 12,000±500 rpm for 2 minutes with help of mixer in special mixing container A to form mixed liquid lime solution, holding of mixed liquid lime solution with formation of foam to obtain hardening foam material containing coal ash, for preventing coal self-ignition.EFFECT: technical result is creation of hardening material with low heat conductivity coefficient, high compression strength, good heat insulating effect, as well as capable of lowering concentration of oxygen in residual space coal.2 cl, 3 ex

Automated system for dust suppression // 2588122
FIELD: technological processes.SUBSTANCE: invention relates to means of dust suppression and can be used for dust removal, irrigation of loose materials at conveyor transportation in points of transfer of civil and industrial facilities. Automated system of dust suppression, which includes a control unit, a high pressure vessel with moistening fluid, water line control circuit. System further includes a compressor station, compressed air feed line and pneumatic-hydraulic nozzle spraying fluid equipped with system of heating cable installed in dust suppression hopper in beginning of conveyor belt. System also comprises shut-off solenoid valves for switching on/off and control solenoid valves to adjust fluid flow and compressed air to nozzles, controlled through a relay unit control device equipped with a network controller installed in form of a single control unit on conveyor frame in area of visual observation of nozzles for manual control. System is also equipped with linear active infrared sensor, receiving and transmitting device which are installed on both sides above level of conveyor belt before dust suppression hopper for determining presence/absence of transported material on belt, signal is received and processed by control device, which by means of relay unit with signal “Conveyor is empty” switches off shut-off solenoid valves and system of cable heating, and for signals “Conveyor loaded”, “Dusted”, “Defective” turns them on. System is also equipped with stationary meteorological meter and dust meter, installed before and after frame in movement direction of transported material, from which data are transmitted and processed in a computer in control panel, then through a network controller are transmitted to a reception-control device, which by means of relay unit automatically corrects operation of solenoid valves and system of cable heating.EFFECT: proposed system ensures connection/disconnection of nozzles depending on presence or absence of transported material on conveyor belt, adjustment of flow rates of liquid and compressed air fed to injectors with due allowance for ambient air parameters in automatic and manual modes.1 cl, 2 dwg
ethod of producing combustion suppressing suspension containing ground fuel ash, for isolation of fires on coal deposits // 2584186
FIELD: fire safety.SUBSTANCE: invention relates to means of suppression and prevention of fires in coal deposits. Disclosed is a method of producing combustion suppressors for suspension containing crushed fuel ash, for localisation of fire on coal deposits, in which material used is crushed fuel ash, aluminium phosphate, magnesium chloride, sodium salt of carboxymethyl cellulose, sodium silicate, sodium bentonite and water. Method involves following steps: a) adding to water 25-30 wt% of crushed fuel ash, 2-4 wt% aluminium phosphate, 2-5 wt% magnesium chloride, 0.8-1.5 wt% sodium carboxymethyl cellulose and thorough mixing to produce mixed solution A; b) adding to water 3-5 wt% of sodium silicate, 1-2 wt% sodium bentonite and thorough mixing to produce mixed solution B and c) adding solution B to solution A while thoroughly stirring to homogeneous state, ratio of solution B and solution A by weight is 1:2.EFFECT: high efficiency of fire suppression and cooling fire areas on coal deposits.1 cl

Systems and methods to prevent gas explosion in a coal mine // 2583964
FIELD: mining.SUBSTANCE: invention relates to mining, in particular to a means of preventing the explosion of gas in coal mines. A system to prevent the explosion of gas in coal mines, comprising a module (1) of gas detection for detecting the concentration of methane and the oxygen concentration in the upper corner of the bottom for the coal and a substantially explosion proof control valve (2) connected electrically to the module (1) of gas detection. Thus intrinsically explosion proof control valve (2) is electrically connected to the device (12), producing inert gas into the top corner of the working face in order to reduce the concentration of oxygen and methane concentrations. Furthermore, the system comprises a windshield to prevent ingress of oxygen from the air inlet in the top corner of generating the working face for coal mining. This gas detection unit (1) comprises at least one sensor I (1-1), determining the concentration of methane, for detecting the concentration of methane in the upper corner of the bottom for coal and at least one sensor I (1-2), determining the concentration of oxygen to detect the concentration of oxygen in the upper corner of the face for coal mining. A windscreen comprises a motor I (6-2), a winding drum coupled to the output shaft of the motor I (6-2), and the wind deflector, wound on a winding drum. This winding drum is located between two adjacent separate hydraulic struts to the working face of coal mining in the direction of coal. Moreover, the engine I (6-2) is located on separate racks hydraulic working face to mine coal. When this explosion-proof exhaust side of the control valve (2) is electrically connected to a drive I (6-1) of the motor, and the drive I (6-1), the motor is electrically connected with the motor I (6-2).EFFECT: technical result is to provide a high reliability, practicality, ease and convenience of operation and improvement of work safety in coal mines.8 cl, 5 dwg

Unit for dynamic dust suppression // 2575372
FIELD: machine building.SUBSTANCE: unit for dust suppression is suggested, is comprised a control block, made with a possibility of signal transmission to a HP air source, connected by discharge air ducts with bellows type tanks with ionised water of opposite polarity via solenoid pneumatic valves, fine spraying atomisers, connected by water lines with the bellows type tanks via solenoid hydraulic valves, and an isolation device of air and water lines, connected with the HP air source by a blowing pipeline, wherein the solenoid pneumatic and hydraulic valves and isolation device are connected by control and monitoring circuits with the control block. Wherein in the bellows type tanks perforate bubble air ducts are installed through their full depth with a pneumodynamic generator of air pressure oscillations at the input.EFFECT: increased efficiency of dust suppression due to the significant increasing of the dynamic pressure of the air-water mixture on dust particles, and its improved wettability to increase the efficiency of gravity forces facilitating dust quicker deposition.1 dwg

Relief of rock-bump and structurally disordered deposits // 2573663
FIELD: mining.SUBSTANCE: claimed process comprises drilling of wells, placing the explosive charges therein and forming of the crushed rock zone by blasts. Wells are drilled from suitable approach courses to place the explosive charges therein and to create the vertical concentrated charge to unload the rock massif in preset direction by a controlled directed shaking blast. Said vertical concentrated charge is surrounded from three sides with a buffer ply of crushed rock by exploding the charges fitted in drilled vertical wells. Then, the vertical concentrated charge is initiated to affect the rock massif strain concentration zone by seismic blast. Note here that the charge bulk is defined by the formula.EFFECT: higher efficiency of relief, safe mining.1 dwg
ethod of prevention of endogenous fires break-out // 2573493
FIELD: fire safety.SUBSTANCE: method of prevention of endogenous fires break-out is proposed, comprising treatment of the surface of coal. At that the surface of coal is preliminary treated with adhesive fluid, and then the microcapsules of temperature-sensitive and water-insoluble material with a diameter from 20 to 5000 microns are sprayed under pressure, which contain an inhibitor in an amount of 50-95% and easily opened at temperatures above 45 degrees.EFFECT: neutralisation of a fire source at the time of its occurrence and blocking of propagation of already existing fire.

Prevention and suppression of dust-gas ejection in open pit // 2572100
FIELD: mining.SUBSTANCE: invention relates to mining. Claimed method comprises the creation of water barriers on the way of dust-gas cloud movement. Said cloud is isolated while pit surfaces are wetted by irrigation atomizers arranged in the pit working zones. Water is fed to said atomizers via pressure lines of the pit dewatering plant by means of the pumps operated in the nominal mode. Said mode allows discharging of water inflows into the pit at maximum efficiency and sufficient stability as far as cavitation self-oscillations are concerned, and keeping of irrigation parameters stable. Note here that irrigation parameters are controlled by water pressure adjustment over the pressure lines length with the help of pipe shutoff valves and accessories. Note here that said nominal operating mode of the pumps is maintained by throttling of said pressure lines or by variation of the pumps drive shaft rpm. Besides, water pressure is additionally controlled by gate valves distributed over pressure lines length.EFFECT: higher efficiency of suppression at transient dust-gas conditions of the pit irrigated zones.1 dwg

Gadget to measure effective gas diffusion in coal // 2571769
FIELD: instrumentation.SUBSTANCE: invention relates to mining, primarily, to coal industry and can be used in mines for determination of effective gas diffusion in the coal at sampling point in real time. Claimed gadget comprises the case to house the power supply, gas accumulation unit composed of a sealed container with chip sampler and pressure transducer, electronic unit with processor, electronic switch and timer, control board, indicator and USB port. Note here that this gadget is provided with extra accumulation unit and pressure transducer while its electronic unit incorporates memory and computing units. Note also that outputs of the main and extra pressure transducers are connected to processor inputs. Processor outputs are connected via electronic switch first inputs to indicator and memory, electronic switch being connected to timer. Electronic switch second outputs are connected with the computing unit. Outputs of the latter are connected to indicator and communication (USB) port.EFFECT: simplified measurement.2 dwg

ethod to predict hazard of coal and gas discharge by means of combination of various information // 2567878
FIELD: measurement equipment.SUBSTANCE: invention relates to a method of prediction of coal and gas discharge hazard by means of combining various information, which may be used in working faces of coal mines. The method is realised by the development of a prognostic model, which combines multiple indices and requires the determination of a row of indices, including initial gas pressure in a coal bed, initial stress of the rock, development impact, coefficient of desorption of rock chips gas, quantitative index of rock chips and similar, and their combinations with the purpose to predict a hazard of coal and gas discharge.EFFECT: due to the prediction method, combining various information, information about coal and gas discharge hazard may be full, and it becomes possible to predict the hazard of gas and rock discharge, disadvantages related to the incompleteness of information when using one index and forecast inaccuracy are overcome, and the accuracy of coal and gas discharge hazard forecast increases.1 dwg

System of dust and gas suppression, ventilation and fire extinguishing during large surface and underground explosions, autogenic and open fires at objects difficult to access and large areas // 2565700
FIELD: mining.SUBSTANCE: invention relates to mine industry, and can be used to control dust and gas content in case of coyote blasts in mines and at borrow pits in rocks of any strength category and watercut degree, and during fire extinguishing of large areas of difficult to access fixed objects. The dust and gas suppression, ventilation and fire fighting system is suggested for mines, it contains: first block comprising mine field with spent chambers and mine tunnels, borrow pit, aquifer, drain system connected in single system, having outputs to open space; at least one second block to form three-phase flow, installed at output to the open space and comprising the ejector device, they contain turbocharger, cryogenic plant, pressure accumulator, cryogenic chamber with build-in at output Laval nozzle; third block to control sequence of switching on of the system assemblies. At that the spent chambers are connected with the aquifer and are tanks to store water supplied to the ejector plant to form the three-phase screen above blasts of the dust-gas discharges and/or for three-phase mixture delivery to the fire spot. Also method of dust-gas suppression is described with use of the said system.EFFECT: increased degree of dust and gas suppression during large coyote blasts and ventilation of the deep borrow pits and mine tunnels.14 cl, 6 dwg

ethod of controlling icing of louver of air intake grid // 2563710
FIELD: ventilation.SUBSTANCE: invention is intended for determining the start of icing of the louver of the air intake grid in the study of thermal processes carried out in order to protect from icing. Icing of the grid of the louver is determined by the formation of frost on the wet gauze bandage which is preliminary placed on the louver.EFFECT: simplicity and reliability of the method.1 dwg
ethod of prevention of ignition of methane-air mixture // 2558068
FIELD: mining operations.SUBSTANCE: invention relates to mining, namely to the field of prevention of ignition and explosion methane-air mixtures, and can be used in coal mining by underground method. The method of prevention of ignition of methane-air mixture is proposed, comprising pneumatic hydro-irrigation of the area of mining operations, the automatic monitoring of methane content by the sensors, and placement of the inhibitor to the mining atmosphere. The difference is that when the concentration of methane in the air is reached to 2.5% the supply of air into the system is automatically disconnected with simultaneous connecting under pressure of the inhibitor of given concentration, the water supply to the pneumatic hydro-irrigation system is not disconnected at that.EFFECT: neutralising the occurred methane-air mixtures and location in the initial stage of their occurrence.

ethod for prevention and control of sudden zonal coal and gas emissions // 2554605
FIELD: mining.SUBSTANCE: invention relates to a method for prevention and control of sudden zonal emissions of coal and gas from coal beds. A method for prevention and control of sudden zonal coal and gas emissions, according to which a mining area is divided into mining zones (5) by distribution of defects and corrugations in a deposit so that boundaries of mining zones are located as far as possible in axial parts of defects or corrugations. Direction of maximum stress is determined in soil along horizontal direction in mining zone (5) by a conventional test method of stress in soil. With that, when an adjacent angle between the measured direction of maximum stress in soil along the horizontal direction and a coal bed passage line is less than 45°, inlet ventilation opening (4) and ventilation opening (3) for a backward jet is located for the mining zone along the coal bed passage line. Then, strike entry driving is performed, and inlet ventilation opening (1) and ventilation opening (2) for the backward jet is located for a working face along the coal bed passage line so that there can be performed mining operations in working face (6) located along the coal bed passage line. When the adjacent angle between the measured direction of maximum stress in soil along the horizontal direction and the coal bed passage line is more than 45°, inlet ventilation opening (4) and ventilation opening (3) for a backward jet is located for the mining zone along the coal bed passage line. Then, strike entry driving is performed, and inlet ventilation opening (1) and ventilation opening (2) for the backward jet is located for a working face along the coal bed passage line. And then, strike entry driving is performed so that there can be performed mining operations in working face (6) located along coal bed inclination.EFFECT: simplifying the method, obtaining a favourable effect of prevention of sudden emissions and reducing concentration of stress in a working face.2 dwg

Explosion-proof jumper device // 2554371
FIELD: mining.SUBSTANCE: invention relates to the construction of jumpers in the mining industry, and more particularly to a device of jumpers in the supply workings of waste scouring faces and in the workings at fire sites in gassy mines. The jumper in the working is set without kerving, mobile and with opening window, closed at the back side with the shield sheet, with reinforced frame on the shield and the openings in the frame to access the radial rods connecting the frame itself, and a tube part with openings on the tube, which enters the middle of the shield sheet and through which a metal rod passes, engaged with the transverse rope, fixed by the anchors in the side walls of the working. At that at the explosion the shock wave moves the no-cut jumper and the shield shutter in the window, that directs a part of the wave on the boards and roof of the working, and the main shock wave is received by the rear fence consisting of bags of flame retardant inert dust, a second barrier shield on the metal rod, separating the bulk materials, and a set of the thrust racks at the output.EFFECT: increasing the stability of the jumper.1 dwg
ethod of prevention and suppression of self-ignition of rock dumps // 2547186
FIELD: mining.SUBSTANCE: method of prevention and suppression of self-ignition of rock dumps comprising the injection of antipyrogen solution into a rock dump is offered. Antipyrogen is fed via the punched pipeline laid in bulk rocks along the dump perimeter along its edges. Meanwhile antipyrogen feeding is alternated with inert gas supply via pipeline. Also the distance from surface to the punched pipeline exceeds the depth of frost penetration in rocks in winter time.EFFECT: improvement of efficiency of the method of prevention and suppression of self-ignition of rock dumps.

Rock dusting device // 2544189
FIELD: mining.SUBSTANCE: proposed device comprises jacket, tank arranged therein and including detachable top element, sidewall and bottom to make inner tank for retention and mixing of composition with inert stone dust and mixer fitted at the bottom to mix the compound with inert stone dust. Note that the tank discharge opening is located at the bottom or sidewall lower part. Besides, this device comprises the pipe extending from the tank discharge opening to jacket discharge opening. Note also that said pipe comprises the pump for transfer of said composition with inert stone dust in said pipe and via discharge line communicated with jacket discharge opening. Besides, this device comprises one or several motors arranged in said jacket to driving of the mixer and pup.EFFECT: lower servicing costs.19 cl, 10 dwg

ethod of preventing explosion of combustible gases in mines // 2543244
FIELD: mining operation.SUBSTANCE: method of preventing explosion of combustible gases in mines is proposed, comprising isolation of mine workings with creation in them of nonexplosive concentration of combustible gases under excessive pressure and placement of channel for transporting the rock mass. And the said channel is filled with foam under pressure greater than the pressure of the combustible gas in the mine working. At that the part of the channel for transporting the rock mass is arranged horizontally, and under this part of the channel a container is placed for draining foam-generating liquid from the decomposable foam which is used for repeated obtaining the foam.EFFECT: increased efficiency of the method of preventing explosion of combustible gases, reduction of flow-rate of the foam-generating liquid.1 dwg
ethod of prediction of explosiveness of deposited dust in gassy mines // 2543238
FIELD: mining operation.SUBSTANCE: method of prediction of explosiveness of deposited dust in gassy mines is proposed, comprising determining in the coal of volatile matter content and mineral impurities in it, measuring the amount of dust deposited in mines and determining the lower limit of its explosiveness. And in the coal bed the areas with inclusions of pyrite are determined, and in the process of coal-face operation in the working with outlet air flow the air flow rate is measured, the content of methane and hydrogen sulphide in it. According to the content of hydrogen sulphide generated during the thermal decomposition of pyrite dust, the lower explosiveness limit of the hybrid mixture is determined.EFFECT: increase in reliability of prediction of explosiveness of the deposited dust in mines.

ethod of dust-producing surface de-dusting // 2542076
FIELD: construction.SUBSTANCE: dust-producing surface is coated with bitumen emulsion containing petroleum bitumen, emulsifier and water. Together with dust-producing surface coating with bitumen emulsion, a suspension containing dust of the dust-producing surface and water is applied. Bitumen emulsion and suspension are applied at the following ratio, wt %: bitumen emulsion 50-60; the rest is suspension. Alkaline solution of sulphonol NP-1 containing 0.6% of sulphonol NP-1, 0.05% of caustic soda and water to fill up to 100% is used as emulsifying agent in the bitumen emulsion.EFFECT: enhanced efficiency and fabricability due to strong protective film formation on dust-producing surfaces based on the surface dust.4 cl, 1 dwg, 1 tbl

ethod for determining boundaries of protected zones in long faces of coal beds // 2542068
FIELD: mining.SUBSTANCE: measurement of relative variation of radiation temperature of the surface of the working face of the bed is made remotely at the distance of 1.0-1.5 m in 3-5 m throughout the long face length; with that, at each measurement point an average value obtained at least in 30 measurement cycles is considered, and a boundary of the protected zone is accepted as distance from a contact line of the bed to the worked-out space to a fixation point of stabilisation of a radiation temperature value. As per the method for determining boundaries of protected zones in long faces of coal beds, remote measurement of relative variation of radiation temperature (infrared radiation intensity) of the surface of the working face of the bed is performed. The first measurement is made at a point at the distance of 3-5 m from a stable hole or a strike entry; the following measurement points are located at equal distance in 3-5 m throughout the long face length. At least 5 point measurements are made at each measurement point. After completion of each measurement cycle for each point in a cycle there calculated are average values. As per average values of at least 30 measurement cycles there built is a chart of relative variation of radiation temperature of the bed working face surface throughout the long face length, and a point of its stabilisation is fixed, which represents a boundary of the protected zone.EFFECT: increasing safe execution of mining operations.1 dwg
ethod for preventing explosion-hazard accumulations of gases and dust in coal destruction zone // 2541970
FIELD: mining.SUBSTANCE: invention proposes a method for prevention of explosion-hazard accumulations of gases and dust in a coal destruction zone, which involves extraction of coal samples from a bed, determination of yield ratio of substances of coal, its gas-bearing capacity, content of fusinite and dust, supply of cooling liquid to a cutter surface and an air-water mixture to the coal destruction zone. Supply of the cooling liquid and the air-water mixture is performed at equal pressure of the liquid in channels of a cutter holder. The cooling liquid is supplied to the cutter surface in a compact form at destruction of coal with the cutter, and liquid in the air-water mixture is dispersed with a possibility of binding explosion-hazard dust fractions; with that, it is supplied via the channel of the cutter holder tangentially to an external cavity of a sleeve with its internal ejecting channel.EFFECT: implementation of the method will allow increasing safety of mining operations on gas-bearing beds, the coals of which tend to dust explosiveness, due to high efficiency of prevention of explosion-hazard accumulations of gases and dust during destruction of coal with an actuating element of a combined machine.

Automatic system of pneumatic hydro-sprinkling and inhibition of highly explosive methane-air mixture (versions) // 2539194
FIELD: mining.SUBSTANCE: invention relates to the coal industry and is designed to control and prevent the explosion of dust-methane-air mixture and improvement of mining safety in mines. The technical result of the proposed invention is to neutralise highly explosive accumulation of dust and gas cloud in work areas of mining machines and providing security. To solve this technical problem, three variants of the invention are proposed. In the first two variants the automatic system of pneumatic hydro-sprinkling and inhibition of highly explosive methane-air mixture comprises channels for water and air supply, filters, electronic gauges, methane sensor. The main difference from equivalents is that an electronic control unit is mounted, receiving and analysing signals from the metering devices of methane concentration, pressure of water and air, and which controls the supply of inhibitor. The channels for supply air and water are connected to the spray nozzle blocks consisting of two chambers. Each chamber is connected with separate inlets to spray nozzles. The channel of air supply through the metering device is connected to the cylinders with inhibitor. In the third embodiment the proposed automatic system comprises three separate channels for supplying water, air and inhibitor. The channels are connected with separate inlets to the nozzle block. The nozzle blocks are made in a three chamber design. Supply of inhibitor is regulated.EFFECT: use of invention enables to improve significantly safety matters at mining operations.5 cl, 8 dwg

Automated system for air-and-gas control and prevention of explosion in working face // 2539052
FIELD: mining.SUBSTANCE: automated system for air-and-gas control and prevention of explosion in a working face with a sprinkling device of a mine working and with a winning machine includes stationary temperature sensors installed on each section of the support and at least one complex measuring device installed on the winning machine and provided with a methane sensor, a temperature sensor and a carbon oxide sensor, which are compactly arranged in a single housing. A sequence of each monitoring and control unit includes logic of comparison of measurements of the temperature sensor installed on the winning machine to measurements of stationary temperature sensors for output of a warning signal at fixation of insufficient coincidence of the above measurements. Besides, monitoring and control units are provided with radio modules for wireless communication to the complex measuring device and the stationary temperature sensors. The complex measuring device can include a carbon oxide sensor, and the monitoring and control units have a possibility of activation of operation of the sprinkling device. On the winning machine there can be arranged two complex measuring devices on maximum remote ends of its housing.EFFECT: minimising explosion hazard by reliable detection of manipulation with gas sensors and prevention of coal self-ignition in a working face.4 cl, 1 dwg

obile device for inhibition of highly explosive methane-air mixtures in mines (versions) // 2537303
FIELD: mining.SUBSTANCE: invention relates to the mining industry and can be used to prevent ignition and explosion of methane-air mixture. The mobile device to inhibit highly explosive methane-air mixture is proposed in two embodiments: mobile on trolley with unit of spray nozzles and knapsack embodiment for immediate protection of workers in the mine. The mobile device for inhibiting highly explosive methane-air mixture in the mines of the first embodiment comprises cylinders with inhibitor, methane sensor, an electronic pressure gauge, a power supply, a trolley on wheels. The device additionally comprises a control unit connected to the system of control and monitoring of the mine and receiving a signal from the sensors of methane and pressure gauges, and transmitting signal to the control valves, which are connected simultaneously with the control unit and cylinders with inhibitor. The control unit is connected to the unit of nozzles comprising two mutually isolated chambers for supplying the inhibitor. In the second embodiment, the mobile device to inhibit highly explosive methane-air mixture in the mines comprises cylinders, methane sensor, and pressure gauges. The device additionally comprises a control unit connected to the cylinders with inhibitor and simultaneously through the flexible connection to the control valve, with at least one spray nozzle to the rod. The control unit and the control valve consist of two isolated chambers for supplying inhibitor, and the control valve is provided with a switching key.EFFECT: neutralisation of highly explosive concentrations of methane and providing safety and absolute protection of miners due to the rapid and mobile delivery and application of inhibition of methane.5 cl, 2 dwg

Air cleaner plant // 2536881
FIELD: process engineering.SUBSTANCE: invention relates to mining and can be used for venting of open pits and cleaning of air forced from working zone. Cleaner 1 comprises housing 14, dusty air feed assy 1 and cyclone chamber 9 with taper bottom. Said feed ass is arranged at rotary platform 15 and comprises air ducts 2 arranged in circle. Said ducts are equipped with blowers 3 and connected with circular channels 7. The latter are communicated with cyclone chamber 9 and provided with nozzles 1 to force air in circle into top section of cyclone 9. Vent pipe 10 is arranged coaxially above cyclone chamber 9. Running gear 16 is mounted under housing 14. Note here that this plant is equipped with rods 13 and guides 12 articulated with tops of rods 13 and suction part of air duct 12 that can turn vertically and horizontally relative to rods 13. Running gear 16 is composed of self-propelled chassis. Cyclone chamber 9 is equipped with dust collector 11. One or several ejectors 19 including confusers 17 and fans 18 are arranged inside vent pipe 10 at preset distance from its base.EFFECT: higher efficiency of cleaning.4 cl, 2 dwg
ethod of prediction of risk of explosion of hybrid mixtures in mines and pits // 2536544
FIELD: mining.SUBSTANCE: invention relates to the field of the mining industry, mainly to coal and ore one, and can be used for the prediction of risk of explosions of hybrid mixtures in mines and gas-hazardous pits. The proposed method comprises the experimental determination of intensity of the emission rate of explosive gases in the mine working, the measurement of the air flow rate and the concentration of gases in the mine atmosphere and the temperature of their ignition. At that the measurement of the air flow rate and the concentration of gases in it is carried out in the process of reducing the ventilation parameters of working, and the dynamics of reduction of the air flow and the increase in the concentration of gases, that constitute the hybrid mixture, is determined. In addition, the temperature of ignition is taken as the value inherent to the component of the hybrid mixture with the lowest temperature of ignition, and the risk of explosion of the hybrid mixture is determined by the product of frequencies of emergencies on the air flow rate and the content of the component of the hybrid mixture with the lowest temperature of ignition.EFFECT: improvement of reliability of prediction by taking into account the dynamics of reduction of the air flow rate and the increase in the concentration of gases.2 cl
ethod of obtaining heterogenic soil composite from wastes of iron ore dressing // 2535852
FIELD: chemistry.SUBSTANCE: method of obtaining a heterogenic soil composite from wastes of iron ore dressing (WIOD), containing iron oxides, includes processing of WIOD with hydrochloric acid. At the first stage the said processing is carried out with hydrochloric acid of a technical 30-33% concentration at 80-90°C for 2 hours with the stoichiometric ratio of components based on the content of iron-containing components in wastes, after which, at the second stage neutralisation of iron oxide, obtained at the first stage with an alkaline agent to pH=7 is realised, separation of the liquid phase is carried out after settling for 1 hour with the dehydration of the finished product to humidity, corresponding to the total moisture capacity of the product in a paste-like state.EFFECT: increase of the specific surface, reduction of permeability.1 tbl, 1 ex

Surfactant selection method for wetting of hard coals using permeability coefficient // 2533562
FIELD: mining.SUBSTANCE: surfactant selection method is offered for wetting of hard coals using permeability coefficient which comprises preparation of coal samples with regular geometrical shape, placing of measuring cylinder on the sample itself, determination of the filtered water surfactant solution, time of filtering, and permeability coefficient, which is determined under the given mathematical expression. Then repeating the measurings for consistently increased surfactant concentration, the correlation profile for the permeability coefficient against surfactant concentration is plotted, and similar measurements with other surfactant types using similar samples are performed. Meanwhile the most efficient surfactant and its concentration are determined by the maximum value of the permeability coefficient for all curves.EFFECT: improvement of mine safety due to increase of efficiency of wetting of boundary zones of coal beds.3 dwg

ethod of forecast of explosion hazard of methane dust mixes during coal destruction // 2533482
FIELD: mining.SUBSTANCE: method of forecast of explosion hazard of firedamps during coal destruction is offered which comprises the determination of methane content of unworked coal, yield of amount of volatile substances, microcomponents of petrographic composition of coal and mineral admixtures in it, measuring of specific dust suppression and identification of criterion of dust explosivity. Meanwhile in coal beds of a mine field the sections with inclusions of pyrite are identified alongside with determination of methane content of unworked coal, volatile content of matters and content of fine dispersed dust of pyrite, parent dust in pores of coal and volumes of free coal fragments of the dust capable at coal destruction to pass into suspended state in a mine air. The quantitative connection between methane content of unworked coal and specific dust emission in the zone of coal destruction by machine cutting head is established. Besides, the offered method envisions the determination in the zone of coal destruction of methane concentration of and the content of fine dispersed dust of pyrite, thermal disintegration of which results in emission of hydrogen sulphide, which decrease the burning point of methane dust air mixes, and also the establishing of quantitative connection between the criterion of dust explosivity and petrographic differentials of coal bed.EFFECT: improvement of reliability of the forecast of explosion hazard of methane dust air mixes.3 cl
ethod of dust suppression in opened coal storages // 2532939
FIELD: mining.SUBSTANCE: method consists in application on dust-forming surfaces of opened coal storages of a mix obtained by compounding of calcium carbide and sodium salt of carboxymethyl cellulose in the ratio 3:1 and dissolved in water at the water solution concentration 5%.EFFECT: improvement of performance of dust suppression in opened coal storages.2 cl, 2 tbl
ethod of predicting risk of methane and dust explosion in mines // 2528807
FIELD: mining.SUBSTANCE: method of predicting the risk of methane and dust explosions in mines is proposed, comprising the experimental determination of the intensity of methane and dust emission at the excavation site, the measurement of the air flow rate and the concentration of methane in it and dust content in the mine air, determination of the ignition temperature of methane and dust, and the frequency of emergency situations. At that the air flow rate and the concentrations of methane in the mine atmosphere is measured in the process of reduction of the parameters of the area ventilation. According to the measurement data the dynamics of the air flow rate reduction and the increase in the concentration of methane prior to its explosive value in the mixture with air is determined. In addition, the ignition temperature of methane and dust is determined at the depth of mining operations at the actual pressure and humidity of air, and the risk of explosion of methane and dust mixture is determined by the product of frequency of emergency situations on the air flow rate, the content of methane and dust.EFFECT: increase in reliability of predicting the risk of methane and dust explosions in mines in the case of reducing the ventilation parameters at the existing excavation sites.

ethod of determining outburst sites in coal beds // 2528304
FIELD: mining.SUBSTANCE: method of determining outburst sites in coal pits, comprising interval drilling well in the bottomhole of development opening, measuring at each interval of exit of drill cuttings and the initial rate of gas emission and determining the possibility of existence in the coal bed of solid solutions of natural gas according to the type of gas hydrates. Then in the drilled well the specific electrical resistivity of the coal bed is measured and the dependency diagram of the specific electrical resistivity of the coal bed from the distance along the well axis is made, using which the width of the site of the coal bed is determined, comprising the solid solution of natural gas according to the type of gas hydrates. Then the rate of outburst Rn is determined taking into account the width of the site of coal bed comprising the solid solution of natural gas according to the type of gas hydrates, and the natural moisture content of the coal bed. At that on the test site of the coal bed at a distance of 0.75÷1.25 m from the first well the second well is drilled. Then the velocity of elastic waves in the array between the wells is determined, for which the piezoelectric detectors are placed in both wells, which are moved with the increment of 0.15÷0.25 m simultaneously in both wells. At that the sites of the coal bed, in which the specific electrical resistivity is 50÷100 times greater than the specific electrical resistivity of the adjacent sites, contain the solid solution of natural gas according to the type of gas hydrates, if the velocity of elastic waves in them is about 2.0÷2.5 km/s.EFFECT: increasing the reliability of determining the outburst in sites of coal beds.4 dwg

ethod of predicting methane hazard in mine // 2527096
FIELD: chemistry.SUBSTANCE: method of predicting methane hazard in a mine includes determining flow of methane from sources thereof on working areas of the mine based on methane hazard of coal seams taking into account the distance between working and contiguous coal seams and residual methane hazard of coal loosened in the backwall. The method also includes determining the output of coal mining equipment, degree of natural degassing of the working and contiguous coal seams and the absolute methane release on working areas of the mine, the maximum value of which determines the category of the methane hazard of the mine.EFFECT: safer mining operations based on gas content owing to high accuracy of predicting methane hazard of a mine based on content of methane in coal seams from numerical values of absolute methane-bearing capacity of excavations.

Sealer of shot-holes for control gas content of coal-beds // 2526954
FIELD: mining.SUBSTANCE: sealer of shot-holes for control gas content of coal-beds comprising a sealing element made in the form of a rigid tubular housing with the end nipple supports and the elastic cuff put on the housing. At that the cuff is mounted on the housing in its end nipple supports through the band. In addition, the sealer comprises a limiting element which is attached to the bottom-hole end of the sealing element, the means of ramming the sealant into the shot-hole, the monitoring and measurement unit, the air supply system with the air supply tubes, and two additional nipple supports. At that the sealer is additionally provided with an elastic sleeve, pressure plate and a punch. At that the rigid tubular housing is made in the form of individual tubular elements interconnected by threaded joint. In front of the nipple support of the first tubular element the elastic sleeve and the pressure plate are located, pressed by the punch mounted on the threaded joint on the outer side of the first tubular element. In addition, the air supply tubes are made passing through the nipple supports, and the elastic cuff is fixed additionally on the resilient sleeve.EFFECT: providing convenience in mounting the sealer in the shot-hole in the confined area of mine workings.1 dwg
 
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