DIN 20379-2:2011-05

In underground hard coal mining, there is a lot of drilling work to be carried out every day, especially for blast hole and anchor hole drilling, whereby this work in the previous years has gained importance for productivity of the longwall mining areas. For economic operation of mines it is of crucial importance to create and maintain great depth cavities, which are artificially made using blasting techniques, so that they are safely controllable, sufficiently dimensioned and require as little redevelopment and expenditures as possible. The anchor technique applied for this purpose and the tunnelling using blasting operations are based on precise, quick and cost-effective drilling work and make sense only through them. Due to various geological conditions the necessary geometric layouts of the cutting types/designs of the bits can vary. In opposition to the specified fitting dimensions, the cutting types/designs shall always be selected depending on rock solidity, existing flushing pressures, the drill used and other boundary conditions. The standards apply for bits of any cutting type and tapers or internal threads for percussive flush drilling used in connection with drill rods according to DIN 20377 and ISO 10207. In the standards, mainly the fitting dimensions of the interior designs of drills are specified in addition to the general designs and hardness values. The standards have been prepared by Working Committee NA 008-04-01 AA "Gesteinsbohren/Gezähe" ("Rock drilling/Tools") at the Mining Standards Committee (FABERG).