Explosive drilling

EXPLOSIVE DRILLING (EN: blast drilling; DE: Schießbohren, Sprengbohren; FR: forage à l'explosif; ES: barrenado por voladura; RU: взрывное бурение) is the method for the construction of the boreholes, using the destruction of the rock within the bottomhole, while using the successive explosions of the charges of the explosive substances, with the removal of the products of the destruction after each explosion. The penetration of the boreholes using the explosions has been proposed for the first time within the USSR by Yu. D. Kolodyazhny and M. I. Kein during the 1942. They distinguish the cartridge (or ampoule) explosive drilling, and the jet explosive drilling. During the cartridge explosive drilling, the charges of the explosive substance are delivered through the pipes into the bottomhole, using the flow of the water or compressed air, with the determined frequency and speed. Upon the impact with the bottomhole, these charges explode, thus destructing the rock, which is removed from the borehole by the flow of the flushing agent. During the jet explosive drilling, they continuously deliver, through the special pipes, to the metering devices of the downhole explosive borer, the two jets of the components for the explosive substances (fuel, and oxidizer), which, during the delivery into the bottomhole, are mixed, and form the flat liquid charge. For the initiation of the charge, from the special container, with the adjustable frequency from 100 to 1500 pulses per minute, there is delivered the initiator (the eutectic mixture of potassium and sodium). The rock, which has been destructed, is removed by the gaseous products of the explosion (toxic), and by the compressed air. The explosive drilling has the status of the experimental works (1981).