Subventions et des contributions :

Subvention ou bourse octroyée s'appliquant à plus d'un exercice financier. (2017-2018 à 2022-2023)

Shotcrete refers to a cement-based mixture projected pneumatically at high velocity towards the target substrate. Shotcrete has been widely used in underground mines as rock support; however, permafrost poses significant challenges to the design and use of shotcrete to support freshly excavated frozen rock/permafrost because the slow hydration of shotcrete mixture on frozen substrates leads to insufficient hardening and malfunctioning of the rock support system. This is unsafe as insufficient hardening may result in rockfalls and subsequent injuries or even fatalities of mine workers. For northern applications, the hydration of shotcrete must be accelerated to ensure adequate strength for rock support; however, excessive heat produced by shotcrete hydration and warm ventilation air within the mine causes thawing of the surrounding permafrost. Thawing is a serious problem because it triggers greenhouse gas emissions (i.e., methane) threatening global climate and it destabilizes the ground making underground operations unsafe.

As mining in colder environments increases in Canada and abroad, innovative shotcrete and rock support systems will be needed for subsurface mine workings excavated in permafrost. However, very limited work has been conducted in this research area. In the next five years, I propose to develop an innovative shotcrete system that can be used as rock support for underground mining in Canada’s North and other permafrost regions. Moreover, fundamental research will be conducted on the heat transfer process in shotcrete and shotcrete-permafrost thermal interactions. The long-term goal of the proposed research program is to establish a framework that includes guidelines and software for the design of underground support systems in Canada’s North.

Mining in Canada’s North plays an indispensable role in the economic and social growth of northern regions and communities; mining accounts for over 20% of the GDP of Canada’s North; it is also the largest private sector employer of aboriginal Canadians. The proposed research program directly contributes to the development, characterization, and understanding of innovative shotcrete for the use as underground rock support in Canada’s North. It will also pave the way for further investigations on the fundamental theory and a framework for underground rock support system design in Canada’s North and other permafrost regions. Finally, this research program will train eight highly qualified Northern mining engineers who can apply their knowledge and academic abilities to mineral resource development in Canada’s North.