Enhancement of cemented rockfill design and practice

矿石贫化被定义为被爆破的矿化岩石（矿石）与诸如矿山回填或废石之类的废料的意外污染。因此，爆破（稀释）矿石的经济价值降低。因此，采矿作业必须采取一切可能的措施来消除矿石贫化的发生。矿石稀释的一个重要来源是用于填充先前开采的块体的回填材料。用废石与水、水泥混合制成的回填土称为胶结堆石。它被用来填补空洞或空采场后，他们已经被开采出来。当生产在与先前充填的采场相邻的采场中进行时，回填材料可能被相邻的生产爆破震动，并且因此，正好倾倒到正在开采的采场中。这个问题被称为矿石贫化由于回填失败。CRF已经是多年的研究课题。许多研究者试图解释CRF的失效，但迄今为止还没有人能够确定CRF的失效机制。很少有工作已经做，以确定有多少爆破影响回填失败。该项目解决了由于爆破振动引发的回填失败而导致的矿石贫化问题，而采场尺寸和计划采场生产顺序等参数。该项目将在马尼托巴省Vale Thompson Operations的Birchtree矿进行。这项工作包括详细审查北美矿山的CRF实践，实验室测试，以确定CRF混合物的强度，并在现场实验，以测量振动回填采场作为相邻的采场正在通过爆破提取。结果将用于确定爆炸振动对回填失效的影响程度。将开发三维计算机建模来模拟Birchtree矿山采场。最后，将根据从实验室和现场实验以及计算机模拟中获得的知识，制定一套设计准则。该项目预计将通过减少回填废料对矿石的污染，为加拿大矿山带来巨大的经济效益。

Ore dilution is defined as the accidental contamination of the blasted mineralized rock (ore) with waste material such as mine backfill or waste rock. As a result, the economic value of the blasted (diluted) ore is reduced. Thus, it is important for a mining operation to take all possible measures to eliminate the occurrence of ore dilution. One important source of ore dilution is the backfill material that is used to fill previously mined blocks. When backfill is made of waste rock mixed with water and cement, it is called cemented rockfill (CRF). It is used to fill the cavities or empty stopes created after they have been mined out. When production takes place in a stope adjacent to a previously filled stope, the backfill material may be shaken by adjacent production blasts, and as a result, topples down right into the stope being mined. This problem is known as ore dilution due to backfill failure. CRF has been a subject of research for many years. Many researchers attempted to explain CRF failure but so far none has been able to determine the failure mechanisms of CRF. Little work has been done to determine how much blasting affects backfill failure. This project tackles the issue of ore dilution due to backfill failure that is triggered by blast vibrations, while parameters such as stope dimensions and planned stope production sequence. This project will take place at the Birchtree Mine of Vale Thompson Operations in Manitoba. The work comprises a detailed review of the CRF practices in North American mines, laboratory testing to determine the strength of CRF mixes, and in-situ experiments to measure the vibrations in a backfilled stope as the adjacent stope is being extracted by blasting. The results will be used to determine how much blast vibrations affect backfill failure. Three-dimensional computer modelling will be developed to simulate the Birchtree Mine stopes. Finally, a set of design guidelines will be developed in light of the knowledge gained from the laboratory and in-situ experiments and computer modelling. The project is expected to render great economic benefits to Canadian mines by reducing ore contamination with waste material from backfill.