A method of secondary blasting used to break large boulders into pieces of manageable size. A hole is drilled to just beyond the middle of the boulder so that the charge is central. The method is fairly quiet and economical.
科学参考收录了60776条科技类词条，基本涵盖了常见科技类参考文献及英语词汇的翻译，是科学学习和研究的有利工具。