Abstract: Based on a full-process survey method，the operational characteristics of the production system at the Sishanling magnetite concentrator were systematically investigated. Under normal production conditions，the key operations including crushing and screening，high pressure grinding rolls (HPGR)， grinding and classification，magnetic separation，and dewatering were systematically sampled and tested. Combined with mass balance calculations，the material flow，metal distribution，and technical perfor⁃ mance indicators of each unit were comprehensively analyzed. The results show that the raw ore has a TFe grade of 27.47%，with magnetite and hematite finely to ultrafinely disseminated and closely intergrown with quartz，making liberation difficult; thus，a stage grinding-stage magnetic separation process is appro⁃ priate. In the crushing and screening system，the medium and fine crushing stages exhibit low reduction ra⁃ tios and coarse discharge particle sizes，resulting in underutilization of equipment capacity. The HPGR achieves an effective reduction ratio of 3.46，but its fine particle generation efficiency is relatively low. In the grinding and classification circuit，the first stage grinding operates stably，the second stage grinding suffers from overgrinding，leading to decreased classification efficiency and equipment utilization. The magnetic separation system performs well overall，with a concentrate TFe grade reaching 65.46%，but some iron loss remains in the tailings，mainly in the form of fine intergrowths. In the dewatering system， both concentrate and tailings moisture contents exceed the design specifications，and the circulation of slimes adversely affects system stability. To address these issues，measures such as optimizing crushing size control，improving the coordination between the crushing and main processes，optimizing the water system，and enhancing dewatering efficiency are proposed. The findings provide valuable reference for pro⁃ cess optimization and capacity expansion in similar magnetite concentrators.

Key words: magnetite, full-process survey, mass balance, high-pressure grinding rolls, grinding and classification, magnetic separation, system optimization