caa a22 4500 463174712 CHVBK 20180406164822.0 cr unu---uuuuu 170326e20070601xx s 000 0 eng 10.1007/s00603-005-0080-5 doi (NATIONALLICENCE)springer-10.1007/s00603-005-0080-5 Controlled Fracture Growth by Blasting While Protecting Damages to Remaining Rock [Elektronische Daten] [S. S. Rathore, S. Bhandari] Summary.: Conventional blasting causes cracks and fractures in the rock. Controlled blasting techniques produce the macrocrack in a desired direction and eliminate microcrack in the remaining rock. Macrocrack development in desired direction is required for extraction of dimensional stone and at the same time there is need to reduce microcrack development in the block and remaining rock. To achieve the objectives, experimental work in the quarries was carried out for separating marble block from the in situ strata as practiced in some of the Indian mines by using detonating cord of 30 to 50 g/m by varying hole spacing, hole diameter, air cushioning, water and sand filled blast-holes. Blasthole notching was carried out. Further, tests were carried out by using various liners inside the blasthole to determine the damages in the extracted block and remaining rock. The designed experimental work was undertaken and rock samples were collected by coring before and after blasting for quantification of microcrack in the rock. P-wave velocity and microscopic studies were conducted for quantification of damages. Experiments were also conducted at laboratory scale for the quantification of damages in single circular and notched holes with variation of stemming and liners. The P-wave velocity close to hole always reduces after blast and in case of NG-based charge and detonating cord it decreases up to 1/3rd. With PVC pipe and paper tube liners decrease is negligible. Thus, by using notched hole with paper tube, decrease in P-wave is minimum indicating least damage. Springer-Verlag, 2006 Keywords: Blast damage quantification, blasthole notching, blasthole liners, P-wave velocity nationallicence Rathore S. S. Department of Mining Engineering, Maharana Pratap University of Agriculture and Technology, Udaipur, India aut Bhandari S. Department of Mining Engineering, JNV University, Jodhpur, India aut Rock Mechanics and Rock Engineering Springer-Verlag 40/3(2007-06-01), 317-326 0723-2632 40:3<317 2007 40 603 https://doi.org/10.1007/s00603-005-0080-5 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00603-005-0080-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Rathore S. S. Department of Mining Engineering, Maharana Pratap University of Agriculture and Technology, Udaipur, India aut NATIONALLICENCE 700 1- Bhandari S. Department of Mining Engineering, JNV University, Jodhpur, India aut NATIONALLICENCE 773 0- Rock Mechanics and Rock Engineering Springer-Verlag 40/3(2007-06-01), 317-326 0723-2632 40:3<317 2007 40 603 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer