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: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=545536
• 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.

胶结膏体回填体（CPB）由细粒尾砂与水和粘合剂混合而成，形成一种非牛顿、非分离、致密的浆体，可用于填充采空区（采场），最终在采空区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矿山的6个采场进行了广泛的CPB现场仪器测量。重点包括量化快速填充期间的充填体行为和评估保留填充质量的障碍物的性能；监测膏体对生产爆破和近场岩爆（最高达3.8纳特利震级）产生的动荷载的响应。现场调查结果以及对代表性CPB样品的实验室测试表明，许多工程设计都严重低估了CPB在静态和动态加载条件下的抗液化能力。此外，某些采矿场景甚至可能需要使用非胶结膏体回填（UPB）——一种目前被认为“风险太大”而根本无法考虑的方法。拟议的研究打算制定一个框架，以评估可能采用UPB的地下采矿条件，特别是如果采用低成本外加剂（通常用于民用建筑工业）以增加回填密度和抵抗液化潜力。四名研究生将花五年时间研究各种混合设计，以确定其微观结构及其对工程性能的影响，包括流体力学（耦合流体流动和应力-应变）行为和动态强度。复杂的数值模拟工具将用于模拟实验室中使用的比例物理模型，从而形成一种可以可靠地用于预测全场规模行为的建模方法。然后将进行一项范围研究，以确定未来项目的潜力，以便在作业矿山中实际测试UPB概念。如果研究结果得到充分实现，其影响将是更有效的采矿做法，并证明安全水平，从而提高经济和环境采矿的可持续性。