A gyratory crusher serves as a crushing machine at the first stage of a mineral processing circuit, reducing the run-of-mine ore to smaller sizes (Ou & Chen, 2023). Packing, or choking, occurs when the crushed material is compressed at the discharge end of the chamber faster than it leaves it. Liner profile refers to the geometry of the liner parts inside the gyratory, the stationary outer concave and the rotating inner mantle. Knowledge of the reasons for packing and methods of changing the liner profile to solve it is important for ensuring the circuit production rate.
The packing of the discharge may be caused by the nature of the material and the feed dynamics. The run-of-mine ore containing much clay or moisture becomes very cohesive; hence, it creates a bed in which the fines bond together and block the passage of the material between bigger particles. In addition, dramatic differences in particle size and shape may dramatically change the mass flow rate inside the chamber (Moncada et al., 2025). Furthermore, when the crusher is fed with the material without previous scalping to filter out the fines, the denser bed can easily solidify at the discharge and cause packing very fast.
Apart from material characteristics, the problem is caused by the progressive wear of the liners. With time, the wear changes the original geometry of the crushing chamber in the machine (Ou & Chen, 2023). This results in creating the “bellying,” which is the mid-section cavity that reduces the volumetric capacity at the discharge compared to the upper parts. This leads to the increased volume being taken into the mid-section while the worn discharge section is unable to release it; hence, the volumetric imbalance causes the packing.
The elimination of the constant packing requires the adjustment of the liner profile to make up for the volumetric imbalance. The best solution in this case is to use the non-choking concave profile. According to modern models, it is possible to create a concave and mantle profile without choke points (Xiong et al., 2024). The typical non-choking profile has the increasing angle to the discharge. By slightly widening the angle in the upper part of the chamber, the intake volume can be limited in order to provide easy processing of the descending material in the lower part.
Moreover, it is necessary to modify the mantle profile in order to avoid the compaction of the material. A constantly flared mantle profile is usually substituted with the stepped or curved one in order to ensure that every next vertical zone of the chamber has increasingly larger volumetric capacity. The key point of this method of continuous expansion is to make sure that there is enough gap between every next zone in order to provide the necessary place for the growing volume of the fragmented ore.
Summing up, packing in a gyratory crusher is a critical problem due to the cohesive ore and progressive wear of the liners, which distort the volumetric capacity of the discharge. By understanding that the core problem of packing is the volumetric imbalance at the discharge, it is possible to introduce a specific adjustment of the liner profile. The use of non-choking concave and volume-expanding mantle designs helps to optimize the mass flow rate and the process performance (Xiong et al., 2024). The proper adjustment of the liner profile to the ore characteristics is the key approach to preventing the problem of packing.
References
Moncada, M., Rojas, C., Toledo, P., RodrÃguez, C. G., & Betancourt, F. (2025). Influence of Particle Shape and Size on Gyratory Crusher Simulations Using the Discrete Element Method. Minerals, 15(3), 232. https://doi.org/10.3390/min15030232
Ou, T., & Chen, W. (2023). Modelling of Gyratory Crusher Liner Wear Using a Digital Wireless Sensor. Sensors, 23(21), 8818. https://doi.org/10.3390/s23218818
Xiong, Y., Gan, J., Chen, W., et al. (2024). Application of Multibody Dynamics and Bonded-Particle GPU Discrete Element Method in Modelling of a Gyratory Crusher. Minerals, 14(8), 774. https://doi.org/10.3390/min14080774
