Rock fragmentation is vital in a sublevel caving operation. The oversize fragments are the most undesired fragmentation category because of their challenges; as such, they require special attention. This study carried out a field test in one of the LKAB’s iron ore mines in northern Sweden to analyse the occurrence of oversize fragments. The analysis involved correlation and regression tests and was performed for different types of rock masses. The results showed that an increase in the percentage of solid rock mass caused an increase in the percentage of oversize fragments. The other rock types, including slightly fractured, highly fractured, and rock mass with minor and major cavities, tended to have a reduced percentage of oversize fragments. The results indicate that oversize fragments can be predicted using linear regression or partial least square regression models with R² values of 0.78 and 0.73, respectively.

岩石破碎在分段崩落作业中至关重要。超大碎片因其挑战而成为最不受欢迎的碎片类别；因此，它们需要特别注意。本研究在 LKAB 位于瑞典北部的一个铁矿山进行了现场测试，以分析超大碎片的发生情况。该分析涉及相关性和回归测试，并针对不同类型的岩体进行了分析。结果表明，固体岩石质量百分比的增加导致超大碎片百分比的增加。其他岩石类型，包括轻微断裂、高度断裂以及具有大小孔洞的岩体，往往具有较低的超大碎片百分比。²值分别为 0.78 和 0.73。