RU2055303C1 - Process of blast breaking of rocks with stratified texture in stripping - Google Patents

Abstract

FIELD: mining industry. SUBSTANCE: process of blast breaking of rocks with stratified texture in strippings involves drilling of parallel rows of vertical holes, their loading with explosive charges and short-delay blasting of charges with the use of detonating cord. Drilling of parallel rows of vertical holes with pitch angle of layers 0 < α ≅ 45^° is performed at angle β to line of disappearance of layers equal to

and at angle 45^°< α ≅ 90^° - equal to

Description

 The invention relates to the mining industry, and in particular to methods of explosive blasting of rocks in quarries and can be used in rock masses with a layered texture, for example, in ferruginous quartzites.

A known method of explosive breaking rocks in quarries, including drilling rows of vertical wells, loading them with explosive charges (explosives) and short-blasting [1]
The disadvantage of this method is that it does not allow the necessary structural changes in the blasted rock mass to be compared with the state in the natural massif, and therefore does not affect the indicators of its subsequent processing in the processes of crushing, grinding and enrichment.

The closest technical solution to the invention is a method of explosive breaking of rocks with a layered texture in quarries, based on the directional softening of structural bonds between minerals at the layered boundaries by drilling wells in a given direction with the subsequent blasting of explosive charges in a certain order [2]
However, during successive blasting of borehole charges using a detonating cord (LH) connecting the charges, the front of the blast wave is substantially shifted relative to the optimal direction of its impact on the layered array due to the fact that the initiation of borehole charges occurs with a delay when the detonation wave propagates into the LH.

 The objective of the invention is to increase the efficiency of explosive breaking of rocks in ore quarries due to the impact of maximum shear stresses at the boundaries of the bedding of rock masses.

, а при 45^о<α≅90^о β ± arctg

± arcsin

, где С_р скорость распространения продольной волны в массиве; D скорость детонации шнура, при этом взрывание зарядов в каждом ряду осуществляют последовательно. При указанном расположении на уступе параллельных рядов вертикальных скважин и короткозамедленном взрывании скважинных зарядов ВВ энергия взрывной волны перераспределяется так, что на границах слоистости образуется деформация под действием максимально возможных сдвиговых напряжений, которые возникают при условии, что двухгранный угол между фронтом взрывной волны и плоскостью напластования слоев составляет 45^о. Использование сдвиговых деформаций на границах слоистости позволяет производить разрыв связей между минералами с наименьшей энергоемкостью.This is achieved by the fact that in the method of explosive breaking of rocks with a layered texture in quarries, including drilling parallel rows of vertical wells, charging them with explosive charges and short-blown charges using a detonating cord, drilling parallel rows of vertical wells at an angle of incidence of 0≅α layers ≅45 ^{о is} carried out at an angle β to the line of strike of the layers, equal to β ± arcsin

And at ⁴⁵ <α≅90 ^of β ± arctg

± arcsin

where C _{p the} velocity of the longitudinal wave in the array; D is the detonation speed of the cord, while the blasting of charges in each row is carried out sequentially. With the indicated location on the ledge of parallel rows of vertical wells and short-blasting blasting of explosive charges, the blast wave energy is redistributed so that deformation is formed at the layered boundaries under the action of the maximum possible shear stresses that arise under the condition that the dihedral angle between the blast wave front and the bedding plane makes 45 ^about . The use of shear deformations at the boundaries of layering allows breaking bonds between minerals with the lowest energy intensity.

 In FIG. 1 and 2 show a ledge with predetermined lines of strike of the layers; figure 3 diagram of the blasting of a layered ore mass.

 The method is as follows.

где С_р скорость распространения продольной волны в массиве;
D скорость детонации шнура.In the course of drilling and blasting operations (BLR) in ore massifs with a layered texture, which are characterized by the direction of the strike line 1 and the angle of incidence of the layers α, on the ledge 2 determine the direction of parallel rows of vertical wells. In the case where the angle of incidence 0 ≅α≅ layers 45 parallel rows ^of vertical holes are arranged so that an angle β to the direction of these series lines strike layer was equal to 1
β ± arcsin

where C _{p the} velocity of propagation of a longitudinal wave in the array;
D cord detonation speed.

 The above range of changes in angle α corresponds to two optimal directions for the location of parallel rows of vertical wells corresponding to lines 3 (Fig. 1). In the manufacture of blasting equipment, depending on the technological conditions, one of these areas is chosen.

± arcsin

Этому диапазону значений углов падения слоев соответствуют четыре оптимальных направления расположения параллельных рядов вертикальных скважин, показанных линиями 4 (фиг.2). Аналогично предыдущему случаю, выбирают одно из четырех оптимальных направлений, руководствуясь технологическими условиями БВР.At 45 ^about ≅α≅ 90 ^{about the} direction of the parallel rows of vertical wells, choose so that the angle between these rows and the direction of the strike line 1 layers was equal
β ± arctg

± arcsin

This range of values of the angles of incidence of the layers corresponds to four optimal directions of the arrangement of parallel rows of vertical wells, shown by lines 4 (figure 2). Similarly to the previous case, one of the four optimal directions is chosen, guided by the technological conditions of the blasting system.

 After this, wells 5 are drilled (Fig. 3), charged with explosive charges and the installation of an explosive network. The blasting of borehole charges is carried out using DS. The blasting of charges in each row is carried out sequentially. In this case, equality of the lengths of segments DS 6, suitable from line 7 to each of the explosive charges in a row, is ensured. Slow blasting of rows of borehole explosive charges in a row is carried out by means of pyrotechnic moderators 8, for example, of the type KZDSh.

. Следовательно, при угле падения слоев 0 ≅α≅ 45^о угол между линией простирания слоев и направлением расположения параллельных рядов вертикальных скважин должен также составлять β= ± arcsin

. В этом случае фронт ударной волны ориентируется параллельно линии простирания слоев и поэтому оказывает максимальное разупрочняющее воздействие на плоскостях напластования слоев. При угле 45^о ≅α≅ 90^о, а также, как и в предыдущем случае, учитывается смещение фронта ударной волны, зависящее от С_р и D. В данном случае угол между линией простирания слоев и направлением расположения параллельных рядов скважин составляет β ± arctg

± arcsin

. Следовательно, в этом случае возможны четыре оптимальные направления расположения параллельных рядов скважин, при которых достигается максимальный разупрочняющий эффект на границах слоистости. При практической реализации способа выбирают одно из описанных оптимальных направлений, руководствуясь критериями практической целесообразности производства БВР с учетом развала взорванной горной массы, перемещения добычных работ и других технологических условий.During successive blasting of wells in a row using LH segments between borehole charges in the rock mass, a plane shock wave is formed, the front of which is shifted relative to the plane of parallel rows of wells by an angle depending on the speed (D) of the blast wave propagation in LH and speed (C _p ) longitudinal wave propagation in the rock mass. In this case, the front of the plane shock wave is oriented along the tangent line connecting the fronts of the cylindrical waves propagating from individual borehole explosive charges. Thus, the actual angle between the planes of the shock front and the plane of the parallel rows of wells is ± arcsin

. Therefore, when the angle of incidence of the layers is 0 ≅α≅ 45 °, ^the angle between the line of strike of the layers and the direction of the parallel rows of vertical wells should also be β = ± arcsin

. In this case, the front of the shock wave is oriented parallel to the line of strike of the layers and therefore has the maximum softening effect on the bedding planes. At an angle 45 ^{of about} 90 ≅α≅, as well as in the previous case, the offset takes into account the shock wave front, depending on C _p and D. In this case, the angle between the line and the direction of stretch of layers arranged in parallel rows of wells is β ± arctg

± arcsin

. Therefore, in this case, four optimal directions of the arrangement of parallel rows of wells are possible, in which the maximum softening effect is achieved at the boundaries of the layering. In the practical implementation of the method, one of the optimal directions described is chosen, being guided by the criteria of practical expediency of the production of explosive blasting, taking into account the collapse of the blasted rock mass, the movement of mining operations and other technological conditions.

 Thus, in the production of blasting materials in rocks with a layered texture, the rational arrangement of parallel rows of vertical wells, taking into account the line of strike of the layers and the angle of their dip, allows us to solve the problem of increasing the efficiency of explosive blasting due to the effect of maximum shear stresses at the layered boundaries.

± 22,6^° В данном примере угол между линией простирания слоев и линией бровки уступа составляет 40^о (фиг.1). В этом случае следует выбрать угол β -22,6^о, при котором будет выполнено условие более рационального развала взорванной горной массы, по сравнению с вариантом соответствующим β+22,6^о.PRI me R 1. In the production of blasting agents in ferruginous quartzites, characterized by the propagation velocity of a longitudinal wave C _p 2500 m / s and the angle of incidence α 30 ^about using DS, with a detonation velocity of the cord D 6500 m / s the angle β between the line the strike of the layers and the direction of drilling of parallel rows of vertical wells is
β ± arcsin

± 22.6 ^° In this example, the angle between the line of strike of the layers and the edge line of the ledge is 40 ^about (figure 1). In this case, you should choose an angle β -22.6 ^about , at which the condition for a more rational collapse of the blasted rock mass will be fulfilled, compared with the corresponding β + 22.6 ^about .

± arcsin

± 35,3± 22,6 В данном случае возможны следующие значения углов:
β₁ 57,9^о; β₂ 12,7^о; β₃ -12,7^о;
β₄ -57,9^о. Этот вариант изображен на фиг.2. Поскольку угол между линией простирания слоев и линией бровки уступа равен 40^о и исходя из критерия оптимальности развала взрываемых горных пород следует выбирать угол β₃= -12,7^о.PRI me R 2. In contrast to the first example, the angle of incidence of the layers is α60 ^about , and the remaining conditions are unchanged. In this case, the angle β is determined by the formula
β ± arctg

± arcsin

± 35.3 ± 22.6 In this case, the following angles are possible:
β ₁ 57.9 ^about ; β ₂ 12.7 ^about ; β ₃ -12.7 ^about ;
β ₄ -57.9 ^about . This option is depicted in figure 2. Since the angle between the line stretch and line edge layers ledge 40 is ^on, and based on the disintegration of optimality criterion blasted rocks should be chosen angle β ₃ = -12.7 ^o.

 The proposed method allows to increase the efficiency of ore crushing due to a more complete disclosure of mineral grains in the layered planes. This, in turn, leads to a reduction in the cost of crushing and grinding the mineral. Along with this, the yield of minerals at the processing plant is increased.

Claims (1)

METHOD FOR EXPLOSIVE BREAKDOWN OF ROCKS WITH A LAYERED TEXTURE AT CAREERS, including drilling parallel rows of vertical wells, loading them with explosive charges and short-blown charges blasting using a detonating cord, characterized in that drilling parallel rows of vertical wells at a dip angle of 0 ^{° at 0 °} carried out at an angle β to the line of strike of the layers equal to

and at 45 ^° <α≅ 90 ^° -

where C _p is the propagation velocity of the longitudinal wave in the array;
D is the detonation speed of the cord,
while the blasting of charges in each row is carried out sequentially.

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