DIN 20352:2016-03

In underground coal mining drilling operations are carried out on a large scale every day, primarily for blasting and anchor hole drilling, and in recent years these operations have become increasingly important for the productivity of mining operations. For the economic operation of mines it is of decisive importance that the cavities artificially created at great depths with the aid of blasting technology are safely controllable, sufficiently dimensioned and created and maintained with the lowest possible rehabilitation and cost expenditure. The anchor technology used for this purpose and heading with blasting work are based on precise, fast and cost-effective drilling work, and only they make sense. This standard applies to a plug-in square connection between the drill rod and the counterpart (drill bit or extension drill pipe), which is a positive connection with a rough clearance fit due to its design. The plug-in square connection is used for clockwise drilling, without flushing medium, with a spiral drill rod. The feed forces are transmitted via the end face of the drill pipe to the contact of the counterpart (drill bit or extension drill pipe). The faces of the square plug-in connection are not covered by this standard. Plug-in square connections for drilling with flushing medium are not considered in this standard. The standard has been prepared by Working Committee NA 008-04-01 AA "Gesteinsbohren/Gezähe" ("Rock drilling/Tools") at DIN Standards Committee Mining (FABERG).