Uncemented paste backfill for underground mining

地下采矿用非胶结糊状回填土

• 批准号: 138459-2011
• 负责人: Grabinsky, Murray
• 金额: $ 1.46万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=508973
• 关键词: Uncemented; paste; backfill; underground; mining

Cemented Paste Backfill (CPB) consists of fine-grained mine tailings mixed with water and binder to create a non-Newtonian, non-segregating, dense slurry that can be used to fill mined-out openings (stopes) where it will eventually harden and provide regional ground support. Over the last four years our research group has carried out extensive field instrumentation of CPB in 6 stopes in three different operating mines. Highlights have included quantifying backfill behaviour during rapid filling and assessing the performance of barricades that retain the fill mass; and monitoring paste response to dynamic loads arising from production blasting and near-field rock bursting (up to 3.8 Nuttli magnitude). The results of the fieldwork, combined with laboratory testing on representative CPB samples, suggest that many engineering designs are significantly underestimating CPB's resistance to liquefaction under both static and dynamic loading conditions. Furthermore, certain mining scenarios may even warrant the use of Uncemented Paste Backfill (UPB) - an approach currently considered "too risky" to be contemplated at all. The proposed research intends to develop a framework for assessing the underground mining conditions for which UPB may be possible, especially if low-cost admixtures (commonly used in the civil construction industry) are introduced to increase backfill density and resistance to liquefaction potential. Four graduate students will spend five years studying various mix designs to determine their microstructure and resulting impact on engineering properties, including hydromechanical (coupled fluid-flow and stress-strain) behaviour, and dynamic strength. Sophisticated numerical modeling tools will be used to simulate scaled physical models used in the laboratory, resulting in a modeling approach that can reliably be used to predict full field scale behaviour. A scoping study will then be carried out to determine the potential for a future project to actually test the UPB concept in an operating mine. If research results are fully realized, the impact will be more efficient mining practices with a demonstrated level of safety, resulting in better economic and environmental mining sustainability.

胶结膏体充填(CPB)由细粒尾矿与水和粘结剂混合组成，形成一种非牛顿、不分离、致密的泥浆，可用于填充采空区(采场)，在那里它最终将硬化并提供区域地面支撑。在过去的四年里，我们的研究小组在三个不同的作业矿井的六个采场进行了广泛的CPB现场仪器测试。重点包括量化快速充填过程中的回填行为和评估保持充填体质量的路障的性能；监测膏体对生产爆破和近场岩石爆破(高达3.8级)产生的动态载荷的响应。现场工作的结果，结合对具有代表性的CPB试件的实验室测试，表明许多工程设计严重低估了CPB在静态和动态加载条件下的抗液化能力。此外，某些采矿方案甚至可能需要使用非胶结膏体充填(UPB)--目前认为这种方法“风险太大”，根本不能考虑。拟议的研究旨在开发一个框架，用于评估UPB可能存在的地下采矿条件，特别是在引入低成本外加剂(通常用于民用建筑行业)以增加回填密度和抗液化潜力的情况下。四名研究生将花五年时间学习各种混合料设计，以确定其微观结构及其对工程性能的影响，包括流体力学(流体-流动和应力-应变耦合)行为和动态强度。将使用复杂的数值建模工具来模拟实验室中使用的比例物理模型，从而产生一种可以可靠地用于预测全场规模行为的建模方法。然后将进行范围研究，以确定未来项目在运营中的矿井中实际测试UPB概念的潜力。如果研究成果得到充分实现，其影响将是具有更高效率的采矿实践和证明的安全水平，从而实现更好的经济和环境可持续性。