SU901517A1 - Method for directional blasting out of permafrost rocks - Google Patents

Description

(k) METHOD OF DIRECTED DISCHARGE

ETERY FROZEN

BREEDS

I

The invention relates to the mining industry and can be used in the development of permafrost alluvial placer deposits in an open way, for example, to form trenches, pits, water bodies, etc.

A well-known slit-explosive method of loosening frozen soil, where the exposed vertical surface is created artificially by mechanical cutting of slits by disc milling or drilling machines, as well as rotary excavators 1.

There is a method of directional ejection of rocks from a horizontal open surface, which involves drilling two rows of wells from the surface to the depth of the excavation being prepared. One row of wells serves to place the main charge in it, and the second row is a sub-well, and the sub-charge diameter is 2.1 times smaller than the diameter of the base charge. During the explosion of the wellbore charges of a child of a row, along the latter, the array is destroyed, as a result of which a bare surface is formed at the contact of the destroyed and monolithic array. The explosion of the main charge of the rock is ejected in the direction of the exposed surface 21.

The disadvantages of such a blasting scheme should include a significant explosive flow. In addition, with an explosion of a child of a row, the surface of the recess is uneven, and the cracks in the massif reach the cavity of the main charges. As a result of this products

The IS of the primary charge, moving along the line of least resistance, immediately after the explosion, breaks through the cracks to the surface, without producing useful work.

20

Claims (2)

The purpose of the invention is to reduce costs. The goal is achieved by the fact that a weakened zone is created by thawing of deep-frozen rocks. This technical solution makes it possible to move up to 90 explosive rock in a given direction and provides the surface of the recess undisturbed by the explosion. The strength of the rocks during their thawing decreases from 50 to 0.1 kgf / cm, as a result of which the consumption of explosives required by is significantly reduced. disconnections of permafrost along the contour of the generating line. The drawing shows a diagram of the implementation of the method. A row of wells 1, for example, with a diameter of 250 mm, is placed from the day surface to the depth of excavation to accommodate the main explosive charge. Then, it is determined by calculation that the generator of the outlet 2 is formed from the side of the non-working side, where the rock is transferred 3 V along the calculated plane of the source of the outlet funnel, the second row of wells are placed, in which metal pipes 5 are placed, which play the role of heaters. These wells, which provide thawing of the entire rock surface, are drilled in increments of, for example, 3-5 m and a diameter of 30-70 mm. The distance between the blast hole, m 1 and wells 4, under the heaters is assumed to be equal to the radius of the largest commoflet. The charge of a commutlet is called a charge, which does not manifest itself on the surface and is limited to the formation of an underground cavity due to compaction and grinding of the environment. In the case of using heaters as electrodes to increase the electrical conductivity of the rocks and reduce the transient resistance at the heater-rock interface, an aqueous brine is poured into the annulus. The electrodes in the row are connected to a power source with a voltage of 0, kV, so that they interact with opposite phases. As a result of the passage of current, the layer of rock is heated to the boundary 6 (defrost halo) in the interelectrode space. The time of thawing of rocks by electric current depends on the volume of heated rocks, their ice content, temperature, grain size and resistivity. Depending on their physicomechanical properties, the thawing layer of rocks can also be created by hydropulsing, chemically, with steam, etc. After the thawing layer has been created, charge 7 explosives are placed in blast holes 1 and all charges are detonated. During the explosion, the frozen mass of rocks 3 is thrown along the generator of the ejection funnel on board the excavation. Using the proposed method will reduce the consumption of explosives by 20-30%, provide a smooth, undisturbed compacted surface along the side of the formed excavation, which in general will make it possible to reduce the cost of mining and increase the efficiency of directional blasting. Claims The method of directional ejection of permafrost, including the formation of a weakened zone in the direction of the ejection in the plane forming the ejection funnel, and the subsequent blasting of explosive charges, characterized in that, in order to reduce costs, the weakened zone is created by thawing permafrost. Sources of information taken into account in the examination (GP and others. Technique and technology of blasting operations in the mines. M., Nedra,} E7o, s, 5h-55. 2. Kushnarev D.M. Explosive energy use in construction. M., stroiizdat, 1E73, p. 279 (prototype).