Characterization of Rock Salt Response to Blasting using Terrestrial Laser Scanning Technology

Abstract

This doctoral research project addresses some of the fundamental aspects for blast design methods in rock salt mines. An experimental field work protocol was devised based on the use of single hole blast (SHB) tests to quantify blasting characteristics in rock salt. Terrestrial laser scanner (TLS) surveys were implemented to capture the shape of SHB craters and enhance objectivity of the reporting methodology. This was done through large scale field testing carried out at three underground rock salt mines. A crater shape model in the form of a power law equation is proposed to define crater breakouts measured through field work. Rock salt characteristic mechanical properties were further analyzed in light of observed field measurements. The analysis led to the definition of a complementary cratering mechanism, due to the interaction between emitted and reflected pressure waves, to describe rock salt blasting behaviour. A semi-iterative procedural workflow is proposed to derive site specific blast design guidelines in rock salt mines. Practical applications of this procedure are presented and discussed, together with a few additional aspects that can help develop a more systematic and global method for optimizing blast patterns in rock salt mines .