The method of pillar failure in conditions of high rock pressure

 

The invention relates to the mining industry, to a method of blasting with blasting and can be used in the development of deposits in conditions of high rock pressure. Method of destruction of pillars includes drilling a series of wells, their loading and blasting. Ore pillar in the process of short-delay blasting shape in horizontal section of the one-sheet hyperboloid of rotation with extremely minimal thickness, the value of which is determined by the formula tmin=2Bnl/Kn[SG], m, where anl- the width of the block along strike, m; [SG] the tensile strength of rocks in compression ore pillar, MPa; Knthe maximum allowable ratio of the specific load of the tensile strength of the pillar, the Dol.ed.;2- effective compressive stresses in the area of erodible ore pillar MPa. This well from Nude pillar have on forming a hyperboloid of rotation and blow up the charges of these wells short-delay method, for example, carlangas pillar and blow up their last. The invention improves the quality of the crushing ore, to reduce the consumption of EXPLOSIVES for blasting, to reduce the volume of drilling operations and losses of wells in the block, to ensure the safety of workers in the production of ore from the block. 2 Il.

The invention relates to the mining industry, in particular to a method of blasting with blasting, and can be used in the development of deposits in conditions of high rock pressure.

There is a method of mass collapse of pillars charges CC parallel-contiguous wells that have rows at a distance from one another equal to or close to the value LS (W).

The number of wells in the beam in each row to be the same regardless of their location and working conditions of each charge (see, for example, and. C. 160134 from 18.04.61 G., C. N. Moines and other Fracture of rocks. M., Nedra, 1975).

Such arrangement of the explosive charge is characterized by a low degree of interaction with the blast due to the fact that the working conditions of the explosive charge in each row and between rows are not constant and vary according to the area of the block (pillar) depending on the voltage clamp conditions occurring in each transverse secheniy consumption of EXPLOSIVES in underground mining. - Mountain journal "Izvestiya vuzov", 1978, 6, S. 22-23) with the decrease of mining increases the specific consumption of EXPLOSIVES for blasting.

Closest to the proposed solution to the technical essence and the achieved result is a way of pillar failure, including drilling rows of holes, loading their charges of EXPLOSIVES and blasting with the formation of zones of tensile stress in isolated areas of the array of columnar shape with an unlimited number of planes outcrops, which are destroyed in the last turn, a powerful explosive charge (see, for example, and.with. 1453001, USSR, CL E 21 41/06, F 42 d 3/04).

However, the disadvantage of this method is that the natural compressive stresses in the destroyed pillar when charges are greatly reduced and does not have a significant impact on the crushing of rocks, i.e. rock pressure does not contribute to reduce energy consumption blasting.

Unified technical result of the invention is the reduction of consumption of EXPLOSIVES for blasting, drilling volumes and loss of wells through the use of compressive stresses in destructible ore pillar for crushing rocks.

Specified single technical result is achieved by the fact that in the known Soobrazitelny sections of a one-sheet hyperboloid of rotation with extremely minimum thickness, the value of which is determined by the formulawherenl- the width of the unit normal to the action of compressive stresses, m; [SG] the tensile strength of rocks in compression ore pillar, MPa; KNthe maximum allowable ratio of the specific load of the tensile strength of the pillar, the Dol.ed.;2- effective compressive stresses in the area of erodible ore pillar MPa.

This well from the exposure of the pillar have on forming a hyperboloid of rotation and blow up the charges of these wells short-delay method, for example, through one in the first place, and along the axis of the pillar well come straight in line with the increase in the mass of the charge wells from the center to the flanks of the pillar and blow up their last.

The mass of the explosive charge 6 the Central part of the pillar and charges 4-5, located on the generatrix of a hyperboloid of rotation, determined by calculation for standard conditions, and the magnitude of the angle () generatrix inclination to the line of contact of the ore body along the strike is determined by the formulathe hail.

Destructible pillar after the treatment the shape of a hyperboloid of rotation, under complex stress-deformed state.

Considering this pillar as a beam clamped on both sides and exposed mountain pressure, we can assume that the natural compressive stresses in it at the time of the destruction of the Central explosive charge reaches a value close to the tensile strength of the ore pillar.

Large stresses occur in the Central part of the pillar and smaller at the flanks.

It follows that the mass of the explosive charge located along the axis of the pillar, should be calculated with consideration of exploding volume of each charge, specific consumption of EXPLOSIVES, reduced in accordance with the ratio of the concentration of natural stresses acting along the pillar, and the coefficient that takes into account the size of the clip exploding area of the array, and to determine according to the formula Q=qoViKiAndikg, (3) where qo- the specific consumption of EXPLOSIVES for blasting without taking into account the stress state of the shattered environment, kg/m3; Vi- the volume of rock mass per charge, m3;
Ki- coefficient taking into account the size of the clip exploding environment, the Dol.ed.;
Andi- coefficient f">
where KNestimated value of the coefficient of loading rocks from the tensile strength at which occurs a dynamic form of rock failure under compression.

According to the research Institute Wastepro, KN=0,70,85 and depends on the physico-mechanical properties of the rock pillar and is determined by the experimental method.

Stresses acting transverse to the extension of the ore pillar (block) given the depth of testing is determined by the formula
2= 0,01HKto, MPa, (5)
where H is the depth of the location please pillar from the earth's surface, m;
the density of overlapping species, t/m3;
Totothe concentration ratio of horizontal tectonic stresses acting on the pillar, the Dol.ed.

Is determined experimentally.

For iron-ore deposits of the South of Western Siberia To theto=3,58.0 in the zone of influence of sewage extraction.

The increase in the mass of the explosive charge located along the axis of the pillar, depending on the volume of destruction, will provide an even split in atie will reduce consumption of EXPLOSIVES for blasting through the use of energy rock pressure on the crushing and as a consequence, reducing the amount of drilling operations.

The proposed solution differs from known as.with. 1453001 the following distinctive features:
- contouring wells from outcrops pillar have on forming a hyperboloid of rotation;
the Central part of the pillar on the top floor it takes the form of a hyperboloid of revolution, and its dimensions provide the conditions under which begins to emerge dynamic form of the destruction of the pillar compression;
- the compressive stress is not released at the time of the explosion, and used for useful work of destruction of rocks;
the explosive charge located on the axis of the pillar with the increase of their mass from the centre and flanks, explode least in terms of the maximum permissible load on the tensile strength of rocks, which contributes to uniform and high-quality crushing.

The essence of the proposed method of pillar failure in conditions of high rock pressure is illustrated in Fig.1 and 2. In Fig.1 shows a plan of the drilling horizon with the location of the explosive charge; Fig.2 is a cross-section of the mining block.

The specified method is as follows. In pillar 1 are generation 2, the distance between which is equal to tmin. From the forming of a one-sheet hyperboloid of rotation - this is the line drawn at an angleto a line normal to the axis of the pillar on the bore 5', located on the border of tmin. Along the axis of the pillar of generation 7 drilling of wells 8, the number of mass charges which increase from the center to the flanks of the unit in accordance with the displacement of destruction.

The mass of the explosive charge in all cases take differentially and is determined by the formula (3).

Primarily short-delay method detonate the charges of 6 wells in the Central part of the pillar on both sides of the axis of generation 7. Then the charges of wells 4 and 5 it, for example, through one. Then the horizontal cross section of the pillar takes the form of a one-sheet hyperboloid of rotation with the parameters at which voltage it reaches its maximum value, commensurate with the tensile strength of rocks. Last also simply blow up the charges of 8 wells located on the axis of the pillar (paraboloid of revolution). These charges occur in conditions of extreme loading rocks, in which there is a dynamic form of rock failure under compression, thereby increasing the crushing without additional energy consumption.

The proposed method is blasting pillars compared to pray consumption of EXPLOSIVES for blasting through the use of high rock pressure in the presence of tectonic stress field;
to reduce the volume of drilling operations and losses of wells in the block.

4. To ensure the safety of workers in the production of ore from the block.


Claims

The method of pillar failure in conditions of high rock pressure, which includes the drilling of a series of wells, their loading and blasting, characterized in that the ore pillar in the process of short-delay blasting shape in horizontal section of the one-sheet hyperboloid of rotation with extremely minimal thickness, the value of which is determined by the formula

where BBC.- the width of the block along strike, m;
[SG] the tensile strength of the rock ore pillar, MPa;
Tonthe maximum allowable ratio of the specific load of the tensile strength, the Dol.ed.;
2actual stresses acting transverse to the stretch in the area of erodible ore pillar, MPa,
this well from outcrops pillar have on forming a hyperboloid of rotation and blow up the charges of these wells short-delay method, for example, through one axis of the pillar well come straight in line with the

 

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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

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