Development method of stratified deposits using chamber system

FIELD: mining.

SUBSTANCE: method involves separation of panels into individually ventilated blocks, in which second working and first working is performed. First working is ahead of second working at least by one block; at that, second working in adjacent blocks is performed simultaneously. Air supply and ventilation mine workings are routed along the panel boundaries. Each block of the panel is outlined on three sides with first block working. Panel and block mine workings are located symmetrically relative to the panel axis and connected to each other by means of cross passages made at the beginning of each of the blocks. Local ventilation plants are located in T-pieces arranged on the panel axis and on its boundaries at connections to main entries. Return ventilation air jet is removed from the T-piece to main entries through a crossing. The panel is developed in the direct order by means of subsequent development of blocks, and reserves of each of the blocks are developed in reverse order. Delivery of mined rock from the blocks is performed to two unloading points located at the connections to main entries.

EFFECT: increasing the panel productivity and reducing the time of its preparation and commissioning.

12 cl, 1 dwg

 

The invention relates to the mining industry and can be used in the development of bedded deposits chamber system.

There is a method of field development chamber system, in which the excavation of minerals is a direct order plots of the width of 400-500 m in the centre of the plot conveyor, before which built the discharge point, and for organizing the movement of air in the workings on the boundaries of the site are installed ventilation jumper (Permyakov, R.S. mining Technology salts / Risperdal. - Nedra, 1981. - S, figure 3.3).

The disadvantages of the method are: the construction of a large number of ventilation jumpers; significant air leakage through the jumper installed in the workings of a large cross section; maintain in a safe condition workings of waste space in the path of movement of ventilation air jets direct mining panel.

There are also known methods, including the preparation of the mining area to the reverse order of testing by pre-drilling air supply and ventilation openings on the borders of the land, the mining of minerals cameras (Silberschmidt, V.G. Technology of underground mining of potash ores/ Vggallery. - M., 1977. - P.45, Fig.14).

The disadvantages of this method are the heart and soul is the need for advance preparation to reverse the order of testing with the sinking of development workings in the entire length of the panel, that slows down time input panel in operation, and the complexity of the ventilation lengthy preparatory workings when the sinking of a single face.

Closest to the proposed invention is a method of mining panels chamber system, consisting in sinking air supply and ventilation openings paired faces on the limits panel, the extraction of minerals drilling and blasting method in reverse order testing panel, the delivery of the rock mass self-propelled transport, the use of fan installations local ventilation air distribution (reconstruction of the ventilation network gypsum mine of OJSC "Knauf Gypsum" / horn. Journe. No. 3. - 2003. - P.26, Fig.3).

However, this method provides for the driving of the workings of the entire length of the panel before cleaning work in the preparation of the panel to the reverse order of testing; limited number of working faces in the panel in the conduct of mining drilling and blasting method.

The technical result of the invention is to increase the concentration of mining operations.

This technical result is achieved in that in the method of mining of bedded deposits of the chamber system, which includes the division of a mine field on the panel, the driving of the air supply and ventilation openings, the working chambers of browser the main way shipping fossil self-propelled transport, ventilation openings using fan installations local ventilation, the panel is divided into separately ventilated blocks, which are preparatory and cleaning works, carry out systematic penetration of air supply and ventilation openings on the panel boundaries on the length of one block, with the refinement panel are direct order through the consistent improvement of blocks, and the stocks in each of the units work out the inverse order.

Each of the blocks in the panel framing on three sides of the block preparatory workings. Panel and block excavations are located symmetrically with respect to the axis of the panel. Sewage treatment works in the adjacent blocks are at the same time. Preparatory work ahead of treatment not less than one unit.

Panel and block generation interconnected through sbec completed in the beginning of each block.

Block the generation of waste blocks are isolated from the panel ventilation openings jumpers.

Fan install local ventilation feature in the tees, on the axis of the panel and at the borders near mates with the main drifts.

Each tee install two fan install local ventilation.

Outgoing stream of air is discharged from the tee in the main drifts through the crossing.

Tees and crossing located at the boundary between adjacent panels, is common to both panels.

Delivery of the rock mass of the blocks to produce two discharge points located near mates with the main drifts.

The essence of the method is illustrated in the drawing, which shows a diagram of the workings to prepare for and mining of bedded deposits chamber system.

In the drawing: 1 - panel border; 2 - main drifts; 3 - panel air production; 4 - axis panel, 5 - panel ventilation generation; 6 - block; 7 - block preparatory development; 8 - linkage; 9 - fresh air; 10 - outgoing current of air; 11 - ventilation jumper; 12 - tee; 13 - fan install local ventilation; 14 - crossing; 15 - handling the item.

The method is as follows.

Mine field mine is divided into panels. Each panel in turn, divided into 6 blocks. The blocks are located on either side of the axis of the panel 4.

To prepare the panels to the development on its borders 1, starting from the main drifts 2, are intake panel 3 and ventilation 5 output the length of one block, which systematically extend for the preparation of subsequent blocks.

When the cooking to the development of the individual blocks are preparatory development block 7, counting each of the blocks on three sides, with panel and block production have symmetrically about the axis of the panel. Block generation connected with panel mount through sbec 8, passed at the beginning of each block.

At the end of the training the first two blocks are guided treatment works and at the same time carry out the preparation of the subsequent blocks. Sewage treatment works in the adjacent blocks are at the same time.

Preparatory work ahead of treatment not less than one unit for the purpose of preparing the inventory unit to the reverse order of testing.

On the borders of the panel, near the main drifts, ventilation panel production interconnected, forming tees 12. Similarly connect block the ventilation output axis of the panel. The tees feature a two fan setup local ventilation (WUMP) 13.

To separate fresh threads 9 and 10 outbound streams of air in zboyco between air supply and ventilation workings install ventilation jumper 11. Fresh air for ventilation produced or mined blocks served on the panel and block intake workings. Outgoing stream of air is discharged from the tees to the main roadway through crossing 14. Tees and crossing, on th the e at the boundary between adjacent panels, is common to both panels.

The refinement panel are direct order through the consistent improvement of blocks, and the stocks in each of the units work out the inverse order. Mining operations are drilling and blasting method, when this generation air using BUMP.

Delivery of the rock mass from treatment and preparatory works are self-propelled transport on two discharge point 15, which is placed on the borders of the panel mates with the main drifts.

After development of the reserves in the block, zboyco between the panel and block excavations install ventilation jumpers to isolate out space unit.

Cleaning and preparatory work in the blocks are at the same time as the ventilation is carried out separately.

The application of this method provides increased performance panel by simultaneously conducting sewage extraction in two blocks, as well as simultaneous conduction of treatment and preparatory works, because of their separation in space and separate airing; preparation of panel blocks eliminates the need for penetration of preparatory workings on the entire length of the panel, which shortens its preparation and commissioning.

1. The method of mining of bedded deposits of the chamber system, including the surrounding division of a mine field on the panel, the driving of the air supply and ventilation openings, the testing chambers drilling and blasting method, the delivery of mineral self-propelled transport, ventilation openings using fan installations local ventilation, characterized in that the panel is divided into separately ventilated blocks, which are preparatory and cleaning works, carry out systematic penetration of air supply and ventilation openings on the panel boundaries on the length of one block, with the refinement panel are direct order through the consistent improvement of blocks, and the stocks in each of the units work out the inverse order.

2. The method according to claim 1, characterized in that each of the blocks in the panel framing on three sides of the block preparatory workings.

3. The method according to claim 1, characterized in that panel and block excavations are located symmetrically with respect to the axis of the panel.

4. The method according to claim 1, characterized in that the cleaning works in the adjacent blocks are at the same time.

5. The method according to claim 1, characterized in that the preparatory work ahead of treatment not less than one unit.

6. The method according to claim 1, characterized in that panel and block generation interconnected through sbec completed in the beginning of each block.

7. The method according to claim 1, characterized in that the components is s waste generation blocks are isolated from the panel ventilation openings jumpers.

8. The method according to claim 1, characterized in that the ventilator installation of local ventilation is installed in the tees, on the axis of the panel and on its borders in pairing with the main drifts.

9. The method according to claim 8, characterized in that each tee install two fan install local ventilation.

10. The method according to claim 8, characterized in that the outgoing stream of air is discharged from the tee in the main drifts through the crossing.

11. The method according to claim 10, characterized in that the tees and crossing located at the boundary between adjacent panels, is common to both panels.

12. The method according to claim 1, characterized in that the delivery of the rock mass of the blocks to produce two discharge points located near mates with the main drifts.



 

Same patents:

FIELD: mining.

SUBSTANCE: method includes development of reserves from a border of an extraction column, drilling from surface of wells into the extraction column and primary setting of the roof. Wells are drilled to the rated line of the roof arch in one row in parallel to a stoping face in the middle part of the limit span of the main roof slab. Eutectic-hard-freezing solutions are filled into wells for the height of 1.5-2 m, rated time is maintained, which is required for melting of ice in cracks of roof rocks and formation of germinal slots, afterwards the wells are filled to the surface with the same solutions, and a hydraulic rupture is carried out in a rock massif.

EFFECT: invention makes it possible to ensure controlled primary setting of strong cracked rocks.

2 dwg

FIELD: mining.

SUBSTANCE: method for shooting of ores and rocks on underground mining works includes drilling-off of a broken volume by opposite wells or blast holes, drilled from upper and lower drilling mines, their charging and exploding. An initiating charge in each well or blast hole is arranged at the distance La=2.25•dw, m from the bottom of the well or the blast hole, where: dw - diameter of a well or a blast hole, m, and distance between ends of opposite wells or blast holes determining thickness of a broken layer, is accepted as equal to L=2•Rr.e.+0.9•Do, m, where L - distance between ends of opposite wells or blast holes, drilled from upper and lower drilling mines, m; Rr.e. - radius of a damage zone from end action of a charge, m; Do - diameter of a bulk piece, accepted for the applied technology, m.

EFFECT: reduced specific and total flow rate of drilling, due to increased efficiency of using explosion energy.

3 dwg

FIELD: mining.

SUBSTANCE: in the period of negative temperatures of ambient air from dehydrated dressing tails briquettes are pressed of ball shape with two diameters related with the following ratio: and volume of a filling material pressed in the form of briquettes of smaller diameter is determined according to the following formula: where Vvol - total volume of solid wastes supplied for briquetting. All prepared briquettes are frozen on the surface, mixed in hoppers with vibrators, transported and placed in a mined space of cleaning units. The ratio of this space filling with briquettes with identical diameter always makes 0.523. If for filling of the mined space a set of briquettes is used in two different diameters, then the coefficient of filling of the mined space will increase to the value of 0.597.

EFFECT: invention makes it possible to increase environmental safety of ore deposits mining in a cryolite zone due to increased volume of solid wastes return from dressing and higher extent of filling of the mined space by means of recovery of a permafrost massif in it.

2 dwg

FIELD: mining.

SUBSTANCE: prior to start of filling works, a recumbent side of a section in a mined space to be filled is poured with water to form an ice crust, afterwards the mined space is filled with crushed dead rocks or frozen briquettes from dressing tails. The ice crust makes it possible to apply self-flow filling at the minimum angle of inclination of a recumbent side equal to αmin.=arctgKfr, where Kfr - coefficient of friction as the filling material moves along the ice crust on the recumbent side of the mined space.

EFFECT: invention makes it possible to increase efficiency of filling works when mining sloping and inclined ore bodies in a cryolite zone due to expansion of a field of application of a self-flow method of dry filling material placement in a mined space by reduction of resistance to motion of this material on a recumbent side.

2 dwg

FIELD: mining.

SUBSTANCE: invention relates to mining, particularly, to sublevel working with sandstowing. Proposed method comprises working the block by odd and even sublevels in ascending order by counter short mining faces vented by all-mine drawdown. First, subdrifts and drops are worked. Seam is worked by counter short mining faces from flank slopes to central slope with direct-flow venting in advance preparation and working of odd sublevels. Mined-out area is filled with solid stowing while even sublevels between odd mined-out sublevels are filled with common stowing. In working, former vent heading is used as a belt heading.

EFFECT: higher safety and efficiency.

3 dwg

FIELD: mining.

SUBSTANCE: mechanised longwall set of equipment for mining comprises sections of a powered support, a hydraulic cutting cleanout machine with actuators and hydraulic cutting heads, joined via metal tubes with a water-supply manifold, a hydraulic booster, a plane with two drives and a plate conveyor with load-carrying plates on rollers, and also comprises a transshipment platform with a mechanised sliding bottom. At the same time the set of equipment additionally comprises a scraper conveyor and a hydraulic support "Sputnik" structurally connected to each other by advancing rams. At both sides of the plate conveyor there are channel guides installed to move coalcutters along them with cable handlers. Besides, the coalcutter installed at the face side of the plate conveyor has a vertical upward direction of a cutting jib in parallel to the face line, and the coalcutter installed at the goaf side of the plate conveyor has a direction of a cutting jib in the bed plane along its border with the roof. The hydraulic machine of the set of equipment is fixed in the end part of the longwall face at the side of the transport mine, and hydraulic abrasive jets work in the transverse plane perpendicular to the direction of cut coal body displacement.

EFFECT: higher efficiency of a mining face due to reduction of duration of a process mining cycle.

4 cl, 14 dwg

FIELD: mining.

SUBSTANCE: extracted core of expendable wells helps to define the outline of bed pinching-out at the area, inside the outline the limits of its standard power are registered and on the base of their average position of seam strike the contoured workings are passed. First cuts are located perpendicular to contoured workings upslope or down-dip and till the outline of bed pinching-out and separate the area to paired blocks. Beginning from the end of each paired block and by moving the front line of extraction by reverse movement there are adjacent extraction workings going from the first cuts to both sides with axes shift and parallel to contoured workings; adjacent extraction workings help to extract the bed selectively and are performed with ground and roof breaking, between the paired blocks there remained are solid blocks with width not more than 10% of abutment pressure zone. Each paired block has formed groups of under-goaf and one support solid block. During seam extraction there drilled are prognostic holes and control the degree of rock-bump hazard is performed, if it is revealed the support solid blocks are unloaded.

EFFECT: increase of safety of developing the area of flat and slope seam liable to rock-bumps and reduction of mineral product losses due to involvement of bed pinching-out areas into actual mining.

3 cl, 3 dwg

FIELD: mining.

SUBSTANCE: mining method by large blocks includes advanced formation of bed underbreaking by plough machine with movement of conveyor into it for output of rectangular blocks of mineral cut from long face above it by cutting longitudinal and lateral slots with the use of supports. The output of alluvial mineral from plough operation is done by separate chain-and-flight conveyor. Plough operation in ripping lip is done simultaneously with cutting mineral blocks from the bed upper part by cutting longitudinal and lateral slots by cutting machines and loading of mineral blocks extracted from long face by transfer platform as well as their locomotive haulage from long face to the point of their discharge into grinding chamber.

EFFECT: invention provides multiple increase of mining face productivity in comparison to the existing level, creation of safe by gas factor and ecologically pure by dust production.

6 cl, 15 dwg

FIELD: mining.

SUBSTANCE: method includes driving of development-temporary workings, working off of primordial chambers of tapered section, their filling with curing mixture forming artificial pillars, formation of massive ore pillar between artificial pillars. Rock pressure is reallocated on artificial pillars. Touchdown working is driven along ore pillar symmetry axis by contact with ore deposits in overlying roof rocks. Blasting wells are drilled from it radially within outlines of natural arches so that ends of these wells most accurately form sizes and surface of line of natural arches in compliance with estimated ultimate strength of overlying rock massif. Complete discharge of massive ore pillar is performed by induced caving of roof rock between artificial pillars on chambers expanding upwards, support of artificial pillars by caved rock is provided. Massive ore pillar stocks are developed with support of overlying roof rock by natural arches resting upon artificial pillars and retaining slopes formed near side surfaces of artificial pillars during loading of broken ore.

EFFECT: increasing reliability of rock pressure control and labour safety.

2 cl, 4 dwg

FIELD: process engineering.

SUBSTANCE: invention relates to mining and may be used in ore dressing. Proposed complex comprises receiving hopper, crushing and screening unit, assembly to feed ore to separation, ore control station, ore lump separators, concentrate and reject discharge conveyors arranged in underground openings. Assemblies feeding ore to separation and X-ray-type separators are arranged on two levels in long openings communicated by box holes to accumulate and feed ore to separators by gates arranged at their outlets. Said box holes are located at 5-7 mm from each other to feature diameter of 1.0-1.5 mm. Assembly feeding ore to separation represents combination of openings, each being 120-40 0m-long and having 2.5-3 m-diameter, and connected with crushing and screening assembly to allow every opening to feed ore of particular size grade to box hole. Every separator comprises, at least, one additional channel for cleaning rejects after separation of concentrate in main channel. Conveyor belts of said main and additional channels are located one above the other. Openings accommodating said assembly feeding ore to separation and separators are spaced apart for 15-20 m along vertical. X-ray-type separator channel comprises, at least, one x-ray useful component content analyser connected with separation device made up of, at least, one pneumatic blowout nozzle. Every aforesaid assembly is equipped with conveyor provided with unloading device driven along openings length. Crushing and screening unit allows producing four flows of ore sized to (-300+120), (-120+50), (-50+15), (-15+0) mm, with (-15+0) mm-ore directed to concentrate discharge conveyor, the remaining flows being used for filling box holes.

EFFECT: higher efficiency of separation and quality of concentrate, reduced costs.

8 cl, 3 dwg

FIELD: mining industry.

SUBSTANCE: method includes use of screw-drilling machine for driving of several first ventilation shafts in ore body and driving several second shafts, while second and each second shaft crosses, at least, one matching first shaft, forming first support walls, supporting ceiling. First supporting ceilings consist of ore body zones between neighboring second shafts, each first support wall has portion of at least one first shaft, passing horizontally through it. Horizontal channels are formed, each of which is placed transversely to matching second shaft between appropriate portions of first shaft, formed in adjacent support walls, for forming of group of continuous ventilation shafts. Second shafts are filled for forming second supporting walls, supporting well ceiling, and first supporting walls are extracted. First ventilation shafts can be made parallel to each other. Second shafts may be directed perpendicularly relatively to first ventilation shafts. In ore body air-outlet and air-inlet ventilation mines can be formed, placed at distance from each other along horizontal line, while first or each first ventilation shaft passes through portion of ore body between air-inlet and air-outlet ventilation mines. Driving of second or each second shaft can be performed by cutting machine, or by drilling or explosive mining.

EFFECT: higher efficiency.

7 cl, 11 dwg

FIELD: mining industry.

SUBSTANCE: method includes partial filling of extracted space of side and central mains by filling stripes from lava extracting shafts. At center of semi-lava on the side of massive, wherein next extractive column will be cut, filling shaft is additionally driven, wherefrom full filling of space between central fill stripe and fill stripe on the side of massive is performed. Preparation of next extraction column is performed under protection of erected fill stripes.

EFFECT: higher safety, higher efficiency.

1 dwg

FIELD: mining industry.

SUBSTANCE: method includes cutting well field portions by driving bed and field mines. At mine fields to be prepared with weak rock stability driving of several field preparatory mines is performed at portion of field with width determined from formula. Bed preparation mines on same portion are driven alter, with displacement of cleaning operations from these may be driven in portions, at which their stability is provided for technological time period with inter-drift blocks of given rigidity.

EFFECT: higher safety.

2 cl, 1 dwg

FIELD: mining industry.

SUBSTANCE: method includes extraction of mineral resource by underground mine method in liquid environment, under protection of water-resistant rock massif. Full flooding of auxiliary extracting and preparatory mines is performed, which provide for start of wiping operations, with working liquid, neutral relatively to mineral resource and enveloping rocks and being under pressure, matching value of pressure at depth of mine. Process of removal of separated rock beyond underground flooded space is synchronized with replenishment of working liquid volume in this space. Working liquid pressure can be formed by effecting it with force liquid, which is placed either in mine shaft, hydraulically connected to lower flooded auxiliary extracting mine, or in mine shaft and force column, placed on earth surface, above mine shaft, and hydraulically connected thereto. Required height of force liquid column is determined from mathematical expressions. After mineral resource extraction is finished within mine field, flooded extracted space is used for placement of toxic and non-toxic wastes of industries or strategic objects, while process of transfer of wastes or strategic objects into liquid environment is performed synchronously with removal of working liquid beyond flooded space in volume, equal to volume of transferred wastes or strategic objects.

EFFECT: higher safety.

3 cl, 1 dwg, 1 ex

FIELD: mining industry.

SUBSTANCE: method includes separating resources of all levels on blocks, in form of upwardly elongated hexahedrons. Blocks on adjacent levels are positioned in staggered order with displacement of some of them relatively to others for half of blocks width. Resources of each block within limits of hexahedron are divided on two portions: hexagonal chamber inside the block and block itself of same hexagonal shape on all six sides of chamber. Preparation and cutting of chamber resources is realized by driving field level drifts and mines, intermediate sub-level drifts and mines, and also level and sub-level orts and drifts, driven through mineral resource, from which resources of chambers and blocks are drilled and exploded. Extraction and outlet of mineral resource is performed in three rows - first chamber resources, than inter-chamber blocks under protection of ceiling blocks, after that ceiling blocks deposits. Outlet of resources from chambers and blocks is performed trough ends of level orts and mines, an also through ends of intermediate sub-level mines.

EFFECT: better use of mineral resources, lower laboriousness, lower costs, decreased block preparation time.

2 dwg

FIELD: mining industry.

SUBSTANCE: method includes determining width of edge zones of block, subjected to influence from support pressure, then preparatory mines are driven along block at limits of these zones and permanent rigid supports are erected therein. After that portion of block from preparatory mines to block center is extracted.

EFFECT: increased mineral resource yield coefficient, safer extraction of inter-panel support blocks, without breaking their carrying ability and without using backfill materials.

2 dwg

FIELD: mining industry.

SUBSTANCE: method includes dividing a level on hexahedral sections of upwardly elongated shape and is prepared by driving of field backup drift. From drift below each section shafts are driven, from which along mineral resource ascending shafts are drilled. For drilling chambers deposits by wells, sub-level drift is driven along mineral resource, access to which is provided by driving field sub-level drift and shafts. Outlet of extracted rock is performed through ends of shafts. After letting out rock from all sections ceiling beam is brought down and also let out through ends of shafts.

EFFECT: lower laboriousness, lower costs, higher efficiency, higher personnel safety.

2 dwg

FIELD: mining industry.

SUBSTANCE: method includes separation of a level on hexahedral sections of upwardly elongated shape and is prepared by driving of field backup drift. From the drift shafts are driven below each section, from which along mineral resource ascending shafts are drilled, meant for drilling from them by horizontal or slanting wells and extracting sections resources. Outlet of extracted rock mass is performed through ends of shafts. After outlet of rock mass from all sections ceiling beam is brought down and let out also through ends of shafts.

EFFECT: lower laboriousness, lower costs, higher efficiency, higher personnel safety.

2 dwg

FIELD: mining industry, particularly methods of underground mining.

SUBSTANCE: method involves advancing breakage face in under-roof layer; drilling bores in the under-roof layer and injecting weakening reagent to separate zones through the bores; drilling blind drift in front of the breakage face, wherein the blind drift has length of not less than breakage face length; drilling bores for following weakening reagent injection from the blind bore; additionally boring intermediate bores between above bores for following gas exhausting; performing under-roof layer development so that non-developed bank is left directly above breakage face support; performing stepwise weakening reagent injection into corresponding bores and evacuating gas from intermediate bores; leaving bores filled with weakening reagent for 1-2 days and supplying the weakening reagent into intermediate bores.

EFFECT: increased efficiency of mineral preparation.

3 cl, 3 dwg

FIELD: mining, particularly methods of underground mining.

SUBSTANCE: method involves cutting mineral by hydrocutting machines and headers from face massif in rectangular blocks; putting on metal cases on the blocks to facilitate loading-and-unloading operations and transportation; loading the cut blocks on hauling truck along side previously opened from breakage face side, wherein the truck position is fixed by spacing apart hydraulic post permanently connected to the hauling truck; moving loaded hauling trucks inside breakage face by hauling tracks along channel, V-shaped guiders or guiding rails with the use of haulage cargo winches arranged in berms near conveying tunnels or with the use of independent drives, wherein the conveyance is carried out to conveying and venting tunnels abutting the breakage face; loading mineral blocks from hauling trucks onto wheeled transport platforms without block turning for following transportation. Distance between rail tracks is equal to rail track width to transport blocks on paired wheeled platforms in which locomotive moves along medium track. Working area face is strengthened by individual hydraulic posts and metal hydraulic jacks and metal roof bars or by mechanized face support. The face support has fastening sections including above hydraulic jacks and roof bars, as well as wheel guiding means sections and hydraulic movers with control panel arranged on each fastening section pair. The roof is controlled by partial filling the excavated space with mineral blocks. Distance between neighboring mineral units arranged on one paired wheeled platform and on adjacent platforms may be identical and equal to distance between guiders in breakage heading. Mineral blocks are cut in several rows, wherein depth of slot at seam ground and roof is two times as thickness of mineral blocks to be cut.

EFFECT: increased output, improved safety and ecology.

3 cl, 14 dwg

Up!