SU1476127A1 - Method of breaking-out rock in blocks - Google Patents

Abstract

The invention relates to the mining industry and is intended for the breaking of rocks, predominantly containing precious mineral crystals. The purpose of the invention is to improve the quality of the blocks being repaired due to the orientation of the fields of destructive stresses mainly along the planes of the intended spalling of the blocks. Wells well in the plane of the alleged spalling of blocks parallel to free surfaces, a depth multiple of the block size. The wells are filled with a non-explosive destructive composition (LDC), including a hardening accelerator (HFC) in order of block placement from the free surface with a time interval equal to at least six times the time to reach the breaking stress when the LDCs solidify. In this case, LDC columns in wells at the level of intersection of the block boundaries by them are dispersed in insulating gaps of a length equal to 1–5 of the borehole diameter. The number of HLA introduced into the LDCs is G = Q / 2 ^N-1 , where Q is the rate of HLA discharge for the section from the wellhead to the 1st insulating gap, kg

N is the number of the well site between the insulating gaps, counting from its mouth. 1 hp ff, 2 ill.

Description

1 The invention relates to mountainous

industry and is intended for blasting rock, mainly containing valuable mineral crystals.

The aim of the invention is to improve the quality of the blocks being repaired due to the orientation of the fields of breaking stresses mainly along the planes of the intended spalling of the blocks.

Fig. 1 shows the location of the wells in the bed, the cross section perpendicular to the direction of drilling; in fig. 2 - placement of self-expanding substance and insulating gaps in the well.

The breaking of rocks is carried out as follows.

In the massif 1 under development, by sinking of the bottom ore receiving openings, the cutting gap and the cutting edge create a horizontal 2 and vertical (in the drawing plane) main free surfaces and an additional free surface 3. At the same time, the main vertical free surface is created, as a rule,

.Ј

05

to

vj

perpendicular to the main system of natural cracks, and further mining of the mineral is conducted in layers from the bottom up. The height of the layer is equal to the maximum size.

1conditioning block (piece) of rock mass (ore).

To break down the ore by the scs. the round of each layer in the planes of the supposed spalling of blocks at a distance of 1 from the free surfaces 2 and 3 and from each other drills a well 4 with a depth multiple of 1 (i.e. all the wells with depth 1, 21 or 31, etc.) , parallel to surfaces 2 and 3. The borehole diameter is taken so that the self-expanding substance hardened in the borehole (non-explosive destructive composition - LDC) ensures complete destruction of the rock in the layer, which is established experimentally.

The number of drilled wells is determined by the equipment used and the organization of work.

While simultaneously crushing several layers of ore, the well of the underlying layer 5 and the overlying layer 6 is arranged in a staggered or one above the other in height, and an additional free surface 3 is formed in a stepped form ahead of layer 5 relative to layer 6 by the value of c 1.

The drilled wells are then successively one after another (the order is shown by the numbers 1, 2, etc.) at an interval of at least t is filled with a mixture of water and LDC powder (i.e. the wells are filled with LDCs in order of the blocks from the surfaces

2 and 3).

The minimum time interval C between the filling of neighboring wells must be such that it does not ensure the breaking of the subsequent block after the complete separation of the previous block.

It is known that most mining processes follow the normal law of probability distribution. Therefore, according to mathematical statistics, after processing the experimental data with a reliability of 0.997, a minimum time of 6d can be accepted, where 6 is a standard deviation (standard) from the average

0

five

0

five

0

five

0

five

time to reach the breaking stress when the LDCs are solidified. The coefficient 6 in this formula is based on the fact that the block breaking time of the previous well (s) can increase from the average time by the value of 3d, and the subsequent time of the breaking of the hole by a well ahead of the average time by the value of also 3d. Therefore, at a time interval of 6 °, the breaking of each layer of ore will occur in successive blocks of length no more than 1, starting from an additional free surface.

The actual time between the filling of neighboring wells (groups of wells) under production conditions may be different due to safety requirements or for organizational reasons, but it should not always be less than 1.

The filling of each well LDCs are dispersed sections 7 with the device between them at the level of intersected boundaries and blocks of insulating gaps 8 of length b 1-5 diameters of the well. These gaps can be made from various inert materials. In the process of filling a well, they can be made from mixtures of self-hardening substances, for example, an aqueous mixture of natural sand with alabaster in a volume ratio of from 1: 1 to 2: 1, where the last digit is the proportion of alabaster.

In order to accelerate the LDCs, a hardening accelerator is introduced into the well in its composition during the manufacture of the aqueous mixture at the site of work. Calcium chloride powder is recommended as such an accelerator. In order to ensure consistent block breaking between sections 7, the amount of hardening accelerator introduced into the mixture for each section is determined by the dependence Q

0

five

H 2

(one)

where Q - accelerator consumption rate

hardening on the area from the wellhead to the 1st insulating gap 8, kg; n is the number of the well site to be filled between intervals 8, counting from its mouth. The consumption rate of the accelerated hardening Q depends on the type of accelerator and the volume of the filled section of the well.

514

gin. For calcium chloride, it is 1-2% of the amount of cement used, i.e.

Q (0.01 - 0.02) K (2)

where K is the amount of cement in the LDCs over the length of one particular well site, kg. If in the well all sections 7 will have the same length and the same cement consumption, then the required amount of the hardening accelerator, according to the calculations according to (1), will be:

- Q

For the first from

wellhead q t ", .t

plot ()

For section 2 Q H

()

For plot 3

(p-3)

For plot 4

(p 4) Q Q

etc.

From the above calculation it can be seen that the rate of consumption of the hardening accelerator changes geometrically with a decrease in each subsequent section by 2 times compared with the previous section. Only with such a ratio is it possible to ensure earlier hardening of each previous section as compared with the subsequent one, which guarantees the sequential separation of blocks along the well lengths. The last well site can be filled without a hardening accelerator.

6

five

about 15

ten

20

25

35 40 30

Claims (2)

1. A method of blasting rocks in blocks, including storm wells in the planes of the supposed spalling of blocks parallel to free surfaces, to a depth multiple of the block size, filling them with non-explosive destructive composition containing cement, and spalling blocks during solidification of this composition, differing from that, in order to improve the quality of the blocking off, due to the orientation of the fields of destructive stresses, mainly along the planes of the intended spalling of the blocks, the filling of wells with non-explosive destructive composition There are in the order of blocks from the free surface with a time interval equal to at least six times the time variation of reaching the destructive stress during solidification of the composition. 2. A method according to claim 1, characterized in that the columns of non-explosive destructive composition in wells at intersection levels of the block boundaries are distributed in insulating gaps of 1-5 diameters of the well and in a non-explosive destructive composition, the hardening agent is introduced in quantities q, kg where Q is the rate of consumption of a hardening accelerator in the area from the wellhead to the 1st insulating gap, kg; n is the number of the area in the well between the insulating gaps, calculated from its mouth. utl: .i li -A. . r it t I . . / T t 5 7 t j them four 0and f JT 3Lf