Abstract
Soundless chemical demolition agents (SCDA), also known as expansive grouts, are cement-like materials which expand upon curing in a confined borehole, generating high expansive pressure. Compared with the traditional drilling and blasting method for rock fragmentation, the SCDA technique has the advantage of reducing greenhouse gas emissions and eliminating vibration. Such features would lower the cost of mine ventilation and reduce the need for additional rock supports due to blast damage. Very few attempts have been made so far to implement SCDA method in underground mines as the presence of high in-situ stress in strong hard rocks is considered a major obstacle. The objective of this multi-phase research project is to revolutionize an alternative, explosive-free method for rock breakage in underground mines.
To tackle the challenge of hard-rock and high-stress environments, a series of large-scale tests on SCDA performance under biaxial stress were designed and carried out at CANMET Mining. High-strength concrete and granite panels of 1m × 1m × 0.25m are loaded biaxially and tested to simulate the condition of an underground mining front. Different drilling patterns are strategically arranged in the panels based on comprehensive numerical modelling studies and implemented to optimize the SCDA efficiency under high confinement. The tests are well-instrumented using multiple systems to help better understand the SCDA performance and panel fracturing. This presentation will describe the large-scale test design, monitoring, and results as well as the latest in-situ pilot tests carried out at a deep underground mine.