Strainburst potential identification and support of stress-fractured ground

尽管目前财政紧张，但矿业部门正在增长，周期可能很长，为加拿大扩大矿产生产创造了独特的经济机会。然而，寻找新的矿体需要数年时间，获得新矿的许可并投入运营通常需要8到15年的时间。因此，通过更深层次的挖掘来延长矿井寿命是最具吸引力的。不幸的是，深度开采的成本更高，只有在一个项目对工人、投资者、社会和环境的风险较低的情况下，投资者才愿意投入资金。本研究主要集中在前两个方面。*作为研究的接受者，利益攸关方确定了需要进行基础和应用研究的两个地质力学方面：(1)应变破裂风险的评估和缓解；以及(2)高应力(破裂)地基的支撑设计，以实现最佳的可施工性，以实现高进展率。这两个因素都是确保深层生产可靠性的关键要素。*拟议的研究涉及通过最近从深层地下建设和采矿中获得的经验所确定的挑战。根据现场观测，找出了当前岩石工程中的两个主要缺陷：*(1)冲击地压潜力识别--冲击地压评估和支架设计的标准方法是基于引起破坏的能量来自地震事件(断层滑动)的前提。这种方法忽略了在开挖附近储存的能量，因此是非常不足的。此外，假设应变爆发的潜在位置与局部变形的可能性有关。如果得到验证，将在通过应变爆发潜力识别方法创造更安全的工作场所方面取得进展。*(2)应力破裂地面的支撑-在深处，如果不在挖掘周围形成一层应力破裂地面，就不可能进行采矿。由于深部岩石的坚硬岩石性质，这种破裂过程与几何体积增加有关，称为膨胀，这对支撑系统施加了严重的压力。目前基于力平衡或能量耗散平衡的设计方法是不充分的，拟议的研究将开发基于变形的支撑设计程序。*将评估岩石破裂过程，以更好地识别应变爆炸潜力和膨胀特性，并改进各自的地面表征技术。*这项研究涉及基础研究、现场监测/观测和反分析，将开发适当地描述深度岩石的方法，以便识别和支持设计应变冲击的可能性。*拟议的研究的独特之处在于，基本的假设已经得到确认和定性验证，因此工业界愿意资助安装监测设备，为这项研究提供数据。*当研究成果应用于采矿作业时，其潜在价值是巨大的。虽然很难量化，但据估计，它对一次运营的利润贡献了数亿美元。它将有助于创造更安全的工作场所，降低投资者风险，降低修复成本，减少生产延误，并可能减少矿石损失。一位行业代表表示，拟议中的研究计划的潜在价值可能在10亿美元左右。

Despite the current financial constraints, the mining sector is growing, likely with a long cycle period, creating a unique economic opportunity for Canada to expand its mineral production. Finding a new ore body, however, takes years and getting a new mine permitted and operational typically takes 8 to 15 yrs. Hence, it is most attractive to expand the mine life by going deeper. Unfortunately, mining at depth is more costly and investors are only willing to commit capital if a project can be executed at low risk to workers, investors, society and the environment. This research focuses on the first two aspects. *The stakeholders, as recipients of research, have identified two geomechanics aspects needing funda-mental and applied research: (1) Assessment and mitigation of risk from strain bursting; and (2) design of support for highly stressed (fractured) ground for optimal constructability to achieve high rates of ad-vance. Both are key elements of ensuring reliability in production at depth.*The proposed research deals with challenges identified through recent experiences from deep under-ground construction and mines. Based on field observations, two key deficiencies in current rock engi-neering are identified: *(1) Strainburst potential identification - standard approaches for rockburst assessment and support design are based on the premise that the damage causing energy comes from a seismic event (fault slip). This approach ignores the energy stored in near the excavation and thus is highly deficient. Furthermore, the potential location for strainbursting is hypothesized to be related to the potential for localized defor-mation. IF validated, progress will be made in creating safer work places through strainburst potential identification methods.* (2) Support of stress fractured ground - at depth it is impossible to mine without creating a skin of stress-fractured ground around an excavation. Because of the hard rock nature of the rock at depth, this fracturing process is associated with geometric volume increase, called bulking, that impose severe strains on support systems. Current design approaches based on force equilibrium or energy dissipation equilib-rium is inadequate and the proposed research will develop deformation-based support design procedures.*The rock fracturing process needed to better identify both strainburst potential and bulking properties will be assessed and respective ground characterizations techniques will be improved.*The research, involving fundamental studies, field monitoring / observations, and back-analyses, will develop means to properly characterize rock at depth for strainburst potential identification and support design.*The proposed research is unique in that underlying hypotheses have been identified and verified qualita-tively such that industry is willing to fund the installation of monitoring equipment to provide the data for this research.*The potential value of the research findings, when implemented into mining operations, is substantial. While hard to quantify, it is estimated to contribute in the hundreds of millions of dollars to the bottom line of a single operation. It will assist in creating safer work places, in reducing investor risks, reducing rehabilitation costs, reducing production delays, and possibly in reducing ore loss. One industry repre-sentative suggested that the potential value of the proposed research program could be in the billion dollar range.