National Research Tomsk Polytechnic University, Tomsk, Russia

A. A. Vorostsov, Post-Graduate Student, AAV88@tpu.ru
V. G. Bukreev, Doctor of Engineering Sciences, Professor

The paper addresses an automated system for detecting and removing metallic fragments from the conveyor flow of iron ore concentrate. The aim of the study is to improve the functional safety and technological reliability of the conveyor line by preventing overload conditions and eliminating ingress of large metal inclusions into crushing equipment. The system is designed for magnetized material, where detection is complicated by the “searching for metal in metal” effect. An integrated architecture is proposed that combines belt scales, a frame-type metal detector and motor current measurement; signal processing and decision-making are implemented on a programmable logic controller (PLC). The methodology is based on the joint assessment of the weight profile, metal detector signal amplitude and the dynamic response of the drive current, which enables discrimination between normal operating modes, short-term overloads and the passage of metallic objects of different mass. The control algorithm provides two responses: standard removal of small fragments by a plough-type diverter and emergency conveyor shutdown when critical conditions are detected (a large metal fragment or an extreme overload). Fullscale industrial tests confirmed the feasibility of the approach and enabled justification of protection setpoints: a metal detector threshold of ≥17 mA for identifying large inclusions, a motor-current threshold of ≥130 A with a disturbance duration of at least 10 s for overload detection, and a reference mass–flow threshold of about 0.2 t/s based on belt-scale data. It is shown that integration of the three diagnostic channels enables transition from reactive to predictive control, reduces probability of emergency downtime and minimizes manual intervention. The results are scalable to similar conveyor sections in mines.

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