The modern technique of rock blasting / Современные методы взрывания горных пород

The technique of rock blasting has within recent years developed from a mere manual occupation in which long-time experience, personal skill and intuition havo played a dominating part, into a technical science in which the fundamental concepts can be taught to students, engineers and workers. The aim of the present book is to provide an introduction to this technology as it has been built up in mining and civil engineering in the post-war years through research, theoretical investigations, field tests and full scale application. 
These years have seen a revolution in the technique as a whole. Drills with tungsten carbide bits and modern drilling machines have greatly improved drilling efficiency, adequate methods of calculating the charge have been worked out, development in electric ignition has increased accuracy and safety in operations. Methods for blasting multiple-row rounds with short delays have created new possibilities for mechanization of the heavy parts of the job and for blasting big rounds. New tools and equipment for charging the drill holes are abont to change completely the procedure of loading. The use of AN-explosives in powder or slurries has reduced the costs of benching. The main principles of tunnel blasting have been established and indicate a further development towards increased mechanization, better fragmentation, higher driving speed and a more extensive use of methods for smooth bla-sting. Such smoothing will also become o.f ever increasing importance in most other forms of rock blasting. <...>