Ore loss refers to the portion of economically valuable mineralized material that fails to be recovered during mining or processing, representing a direct reduction in the value that could otherwise have been extracted from a deposit. Loss can occur at multiple stages: ore may be left behind in the pit due to imprecise dig-limit definition, misclassified as waste due to sampling error, left in pillars or unmined remnants in underground operations for geotechnical stability reasons, or lost during processing due to incomplete recovery in the metallurgical circuit. In bauxite and iron ore mining, ore loss often results from overly conservative dig limits applied to avoid contaminating product specifications with adjacent waste material. In gold mining, ore loss can occur through incomplete leaching or flotation recovery, particularly with refractory ores that resist standard processing. In diamond mining, ore loss is a significant concern because diamonds are sparsely distributed and physically small, meaning inefficiencies in dense media separation, X-ray sorting, or even crushing-induced breakage can result in valuable stones being lost into tailings streams, making careful circuit design and monitoring essential to minimizing this form of loss.
