Flameless blasting

FLAMELESS BLASTING (EN: non-flame blasting; DE: flammenloses Schießen, flammenloses Sprengen; FR: explosion sans flamme; ES: voladura sin llama; RU: беспламенное взрывание) is the method for the blasting without the forming of the flame.The Hydrox cartridge

The carriers of the energy are the gases, which are compressed to the high pressure (the Airdox method), liquid (Cardox) or solid (Hydrox) substances, which are able of the rapid expansion or evaporation with the forming of the large quantity of gases. They use the flameless blasting within the mines, which are dangerous because of gas and dust; their usage permits us to mechanize the process of the breaking the coal and weak rocks within the the retreating and preparatory stopes. The first attempts for the creation and usage of the means for the flameless breaking belong to the start of the 20-ies (Great Britain, USA). Within the USSR, during the 1931-33, there have been created and tested the model of the cartridge of the Cardox type with the design by Dolgov, the cartridges of the Hydrox type by N. P. Komar, and the cartridge of the "VUGI" type by D. I. Volpin, I. I. Stukanev, and G. I. Podbelskiy.

The Airdox cartridge

The principle of action of the modern cartridges of the Hydrox type (Figure # 1) is based on the chemical reaction of the powdered charge, as the result of which there forms itself the significant quantity of the inert gases (60-70%), water vapours, carbon dioxide, and nitrogen, and is created the high pressure (180 megapascals).

After reaching of the pressures, which are exceeding the limit of the strength of the shear disk, there takes place its destruction, and the gases rush into the blasting borehole through the exhaust holes, causing the destruction. The principle of action of the method for the breaking by the compressed air with the high pressure (Airdox) is based on the instantaneous release of the compressed air from the pneumatic cartridge, which takes place without the alteration of the chemical composition of the substance (Figure # 2).

The compressed air is produced by by the compressor with the high pressure (80 megapascals), and enters into the trunk pipeline, which has been laid within the mine workings, and from there through the flexible armoured hoses into the pneumatic cartridge. Depending onto the strength of the massif, which is being destructed, the pressure within the cartridge is regulated by the thickness of the shear disk. The principle of action of the Cardox is based on the instantaneous transformation of the liquid carbon dioxide, which is enclosed within the steel cartridge, into the gaseous state (Figure # 3).

The Cardox cartridge

The carbon dioxide within the cartridge is heated by the element, which is ignited during the passage of the electrical current through the initiator of combustion. After reaching the pressure of 400-500 megapascals, the gases breach themselves from the cartridge into the cavity of the blasting borehole and destruct the massif. The charging of the cartridges with the carbon dioxide is performed on the surface of the mine.