Method for explosive loosening of hard rocks using charges with air cushion

FIELD: mining.

SUBSTANCE: method involves drilling of blast holes with increased subdrilled area, their charging with an air cushion arranged in the above subdrilled area, and explosion of mine rocks. Air cushion with length of 6-10 diameters of the well is created below actual level of bench bottom by 2-3 diameters of the well. Additional charge with length of 10-20 diameters of the well is arranged under the cushion.

EFFECT: improving the efficiency of charges.

3 dwg

 

The invention relates to the field of mining industry, in particular to the development of strong rocks in difficult conditions when excessive resistance on the soles of the ledge or marking soles, etc.

Widely known methods of explosive loosening of rocks with a separation of charge on the part of the air gaps [1]. Increasing the exposure time of the pulse of the explosion on the array decreases pereselenie near charge, which contributes to a significant improvement of the quality of crushing while reducing specific consumption of EXPLOSIVES.

It is also known that the location of the air gap at the bottom end of the charge, creating an air cushion, in addition to a significant increase in quality crushing, excludes reverse ejection blasted rock at the upper edge of the ledge, at the expense of directional emission of the rock mass in the direction of the slope of the ledge is exposed almost half and has a steeper angle [2].

Our studies revealed that the charges with an air bag, allow to work excessive resistance on the soles of the ledge and even when inflating the foot of the escarpment can achieve a qualitative study of the soles of the ledge when the design change charge.

The closest essentially a solved problem is the way of the explosive loosening rocks with an air bag, in which air p is dushku place in the advanced drilled part of the well, below the design elevation of perebor [2, P80]. The disadvantage of this method is inflated value of perebor - up to 5.5 m (22-25 diameter wells)when the length of the airbag 3 m (12-14 diameter wells).

The technical task to be solved by the invention, is to increase the efficiency of the charge air cushion in conditions of excessive resistance to the action of an explosion through the use of a special construction of the explosive charge.

This object is achieved in that in the method of explosive loosening rock charges with an air bag, comprising the drilling of blastholes with increased pereboom, their loading with accommodation in peribere airbags and blasting of rocks, according to the invention an air cushion length 6-10 diameter wells are placed below the actual level of bench bottom 2-3 diameter of the hole, and below it place additional explosive charge length 10-20 diameters of the well.

The implementation of the method presented in the diagrams.

Figure 1 presents the design of the charge; figure 2 shows a video frame of the explosion borehole charges with air cushion of foamed polystyrene, figure 3 - view of the face and the collapse of the rock mass after the explosion.

The way of the explosive loosening rock charges with air cushion as follows.

At the mouth of the PE 1 drilling of wells 2 by the calculation grid with increased pereboom. Then proceed to the formation of a charge of air cushion in peribere. To do this, first place the lower action 3 on the conductor initiating impulse 4, such as detonating cord (LH) or waveguide system SINV and form the lower explosive charge 5 length 10-20 diameters of the borehole. Above it creates an air cushion 6 length 6 to 10 diameters of the borehole, for example, falling asleep polystyrene foam, with the top mark airbag 6 should be 2-3 diameters well below the soles of the ledge 7. Then in the borehole 2 post action 8 on the conductor initiating impulse 9 for the upper charge 10, after which form the stemming 11. The length of the bottom of the battery 5 and the airbag 6 pick empirically depending on the tasks. So, at highly inflated level 7 soles increase the length of the lower charge, while a high resistance on the soles of the ledge increase the length of the airbag 6. After charging all wells mounted explosive network. Preferred contractor scheme with longitudinal rows in the direction of the slope of the escarpment.

When the detonations of conventional charge air cushion of the incident shock wave, reaching the bottom of the borehole, is reflected by the products of the detonation propagates the reflected shock wave with sharply increased in 10 times the pressure on her front, and can result in favorable the conditions for the best separation on the bench bottom [2, p.46]. In charge of the proposed design interact with the shock wave and the gas flows from the two charges, as a result, according to [3], the pressure in the air gap increases in 15-20 times, significantly increasing the duration of the explosive impulse and isolation breeds over sole ledge increase. This assumption was confirmed experienced an explosion using charges with the suggested settings below the foot of the escarpment. When inflating the foot of the ledge 5 meters blasted rock mass was discarded parallel to the surface of the working platform, revealing the slope of the ledge completely (see figure 3).

Thus, the inventive method explosive loosening rock charges with an air cushion by placing additional charge under air cushion in peribere provides a gap on the bottom of the ledge when blasting with high resistance parameters, thereby making it possible to solve the problem.

Sources of information

1. Marchenko, L.N., Kudryashov B.C. guidelines for the application of borehole charges, distributed air gaps on open mining /Coll. Explosive case No. 51/8. M.: Nedra, 1963. - S-206.

2. Zhunusov K. Blasting rock charges with air cushion. Alma-ATA, Nauka, 1979. P80-81 (prototype).

3. Gubkin V. the more effective is aktivnosti borehole charges with air gaps // the Problem of destruction of rocks by explosion. M.: Nedra, 1967, S-159.

The way of the explosive loosening rock charges with an air bag, comprising the drilling of blastholes with increased pereboom, their loading with accommodation in peribere airbags and blasting of rocks, characterized in that an air cushion length 6-10 diameter wells create below the actual level of bench bottom 2-3 diameter of the hole, and below it place additional explosive charge length 10-20 diameters of the borehole.



 

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1 dwg, 1 ex, 2 tbl

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