Further development and testing of the dry drilling technology to produce deep boreholes for the underground disposal of heat generating radioactive wastes

The complex and compact dry drilling equipment EHV 1202, patent No. 4127472, in connection with the modified lock drill head SBK 602 is a drilling equipment developed for underground use by means of which, after eliminating manufacturing defects and carrying out the necessary retrofitting, directional holes of 600 mm in diameter up to a depth of 600 m can be drilled in salt formations for different purposes. The equipment is automated to the extent that during the drilling only 2 persons (1 toolpusher and 1 assistant) are required to operate it, and drilling depths of between 15,0 m and 18,0 m per shift can be reached. The measuring data acquisition and processing unit could be successfully tested, inspite of the short drilling time available, down to a depth of 62,0 m. The accurate automatic drilling head control, after a hand-operated test phase, is possible by expanding the available software without hardware retrofitting, so that in future the additionally required ''steersman'' can be spared. (orig./HP)