Developing Innovative Shotcrete as Rock Support for Underground Mining in Canada's North

开发创新喷射混凝土作为加拿大北部地下采矿的岩石支撑

• 批准号: RGPIN-2017-05537
• 负责人: Liu, Wei
• 金额: $ 1.46万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=657812
• 关键词: Developing; Innovative; Shotcrete; Rock; Support

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.

喷射混凝土是指以气动方式高速喷射到目标基底的水泥基混合物。喷射混凝土已被广泛用于地下矿山作为岩石支护;然而，永久冻土对喷射混凝土的设计和使用提出了重大挑战，以支持新开挖的冻结岩石/永久冻土，因为喷射混凝土混合物在冻结基质上的缓慢水合导致岩石支护系统硬化不足和故障。这是不安全的，因为不充分的硬化可能会导致岩石坠落，随后造成矿工受伤甚至死亡。对于北方应用，必须加速喷射混凝土的水合作用，以确保岩石支护有足够的强度;然而，喷射混凝土水合作用产生的过多热量和矿井内的热通风空气会导致周围永久冻土融化。解冻是一个严重的问题，因为它会引发温室气体排放（即，甲烷）威胁全球气候，并使地面不稳定，使地下作业不安全。** 随着在加拿大和国外较冷环境中采矿的增加，在永久冻土中挖掘的地下采矿工作将需要创新的喷射混凝土和岩石支撑系统。然而，在这一研究领域开展的工作非常有限。在接下来的五年里，我建议开发一种创新的喷射混凝土系统，可用作加拿大北部和其他永久冻土地区地下采矿的岩石支撑。此外，还将对喷射混凝土的传热过程以及喷射混凝土与冻土的热相互作用进行基础研究。拟议研究计划的长期目标是建立一个框架，其中包括加拿大北部地下支撑系统设计的指导方针和软件。加拿大北部矿业在北方地区和社区的经济和社会发展中发挥着不可或缺的作用;矿业占加拿大北部GDP的20%以上;它也是加拿大原住民最大的私营部门雇主。拟议的研究计划直接有助于开发，表征和理解创新的喷射混凝土，用于加拿大北部的地下岩石支撑。这也将为加拿大北部和其他多年冻土区地下岩石支护系统设计的基础理论和框架的进一步研究铺平道路。最后，该研究计划将培养八名高素质的北方采矿工程师，他们可以将自己的知识和学术能力应用于加拿大北方的矿产资源开发。