Large borehole blast

Large borehole blasts are borehole blasts in boreholes longer than 12 m in length and with diameters over 50 mm. They are used in technical rock extraction, e.g. B. used in quarries and also in potash or rock salt mining. Blasting in deep boreholes does not count among the large borehole blasting.

The person authorized to blast requires a special course and entry of the authorization in the certificate of proficiency for blasting large boreholes .

execution

First, the boreholes with a diameter of up to 20 cm are drilled using drill jigs. Then explosives are introduced into the borehole, which is then detonated. There are powdered explosives to ANC base , Sprengschlämme with shock cartridge of emulsion explosive , or gelatinous explosives with detonating cord used. When blasting large boreholes in quarries, several hundred kilograms of explosives are usually used in one ignition cycle, thus loosening and crushing several thousand cubic meters of rock. The aim is to achieve a good chunkiness of the pile in order to guarantee further machine processing.

literature

• Author collective: The blasting party . in mining and in the stone and earth industry. Ed .: SDAG Wismut. 3. Edition. German publishing house for basic industry, Leipzig 1977, p. 204 .