Causes and effects of backfill dilution in open stoping method

露天回填法充填稀释的原因及影响

• 批准号: 41603-2010
• 负责人: Mitri, Hani
• 金额: $ 1.6万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=521547
• 关键词: Causes; effects; backfill; dilution; open

The use of mine backfill in open stoping method to mine steeply dipping ore deposits is very common in underground hard rock mines in Canada and around the world. In a sublevel open stoping environment, the use of backfill allows for safe, pillar-less, and economic extraction of an orebody with longitudinal and transverse stoping methods. This is particularly true when dealing with ore deposits that are situated at great depths below ground surface where the in situ stress fields are invariably high, and where complex geological features like faults, dykes and shear zones are frequently encountered. Once primary stopes are mined out and backfilled, mining of secondary stopes can be scheduled in accordance with a planned sequence that aims for full, pillar-less recovery while pushing high stress fields away from the area being mined. While widely accepted, the inherent weakness in this process is that, often enough, the backfill column side facing the stope will fail partially or not into the secondary stope during the ore mucking process, thus resulting in ore dilution. Such backfill dilution results in delayed productivity due to increased stope cycle time, and in lower mine profitability caused by the reduced mill grade. Depending on the significance of backfill column failure, this may also result in delays in the mining of upper stopes due to time lost in floor repair and preparation. The short term objectives of this project thus are: 1) to determine the causes of backfill dilution in open stoping method with respect to stope type, design, sequencing and cycle time, backfill material type, strength and fill practice, and stope blast design, and blasting sequence, and 2) quantify the effects of such dilution on stope recovery, mill grade and productivity. The impact of backfill dilution on mine scheduling and economics is not properly accounted for in the current practice of underground mine design. The proposed research is a first attempt to understand and document the causes and effects of backfill dilution. It is believed that the proposed research will set the stage for significant research partnership with the mining industry to develop together what would be the first Canadian best practices guidelines for mine design against ore dilution.

在加拿大和世界各地的地下硬岩矿山中，采用露天回填法开采陡倾矿床的情况非常普遍。在地下露天采矿环境中，使用回填可以通过纵向和横向采矿方法安全、无矿柱且经济地开采矿体。当处理位于地表以下较深处的矿床时尤其如此，这些地方的地应力场总是很高，并且经常遇到断层、堤坝和剪切带等复杂的地质特征。一旦主要采场被开采并回填，就可以按照计划顺序安排次要采场的采矿，其目的是实现全面、无矿柱恢复，同时将高应力场推离正在开采的区域。虽然被广泛接受，但该过程的固有弱点是，在矿石出渣过程中，面对采场的回填柱一侧通常会部分或不进入二级采场，从而导致矿石贫化。由于采场周期时间增加，这种回填稀释导致生产力延迟，并且由于磨机品位降低导致矿山盈利能力下降。根据回填柱故障的严重程度，这也可能由于地面修复和准备时间的损失而导致上部采场的采矿延迟。因此，该项目的短期目标是：1）确定露天采矿法中回填稀释的原因，涉及采场类型、设计、排序和循环时间、回填材料类型、强度和填充实践、采场爆破设计和爆破顺序，2）量化这种稀释对采场回收率、磨机品位和生产率的影响。当前地下矿山设计实践中没有适当考虑回填土稀释对矿山调度和经济性的影响。拟议的研究是理解和记录回填稀释的原因和影响的首次尝试。据信，拟议的研究将为与采矿业建立重要的研究伙伴关系奠定基础，共同制定加拿大第一个针对矿石贫化的矿山设计最佳实践指南。