Safe distance for telecommunication radiofrequency transmitter with frequency below 10 MHz in underground mines
Abstract：The computing model of safe distance between detonator and radiofrequency transmitter working at the frequency band below 10 MHz in coal mines was established.The detonator pin was considered as a loop antenna.Based on that,obtained the calculation formula of the internal resistance of detonator pin,the mutual and the external inductance of the loop line,and then the total current formula in the loop line was obtained,the calculation formula of safe distance between RF transmitter and detonator was deduced at the end.Two influences on safe distance in the model were analyzed,which were caused by the area of detonator pin and working frequency of RF transmitter.The results show that the safe distance between RF transmitter and detonator in underground mines is 3 meters.In other words,as long as the distance is over 3 meters,the radiation energy of transmitter with frequency below 10 MHz,will not be a threat to detonator.
Keywords：underground minesafe distanceworking frequencyelectric detonatordetonator pin area
Publication Date：2011-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)