Failure analysis of mantle/head liner of a cone crusher at a diamond mine in botswana

Abstract

Cone crusher basic operation entails the application of compressive force between a gyrating mantle and a stationary bowl. The mantle and bowl are shielded with manganese steel liners, which wear away during operation and are the most replaced components. The mantle liner (ML) of a diamond mine in Botswana requires replacement at an average of 3600 h of operations, 720 h short of the manufacturer’s 4320 h expectancy. This study analyses ML failure modes and mechanisms while suggesting measures to mitigate this recurring mining operational challenge. This study used a combination of visual inspections, metallurgical investigation, and microstructural studies to provide insight into the failure. The results established abrasive wear, plastic deformation, subsurface cracking, tribocorrosion-induced cracking (TIC), and surface fracture as the ML failure modes. Abrasive wear initiates ML degradation through microcutting, ploughing, microcracking, pitting, and spalling. Impact forces during crushing of kimberlite ore containing hard minerals such as diamond and quartz induces plastic deformation, leading to twinning-induced plasticity (TWIP) and strain accumulation, which promotes the initiation of subsurface cracks along weakened grain boundaries. Cyclic loading promotes the propagation of existing intergranular cracks, which eventually forms surface fracture. Furthermore, corrosion products on the liner’s inner section (Al₂O₃, MgO, and CaO) contributed to TIC. This can further interact with subsurface cracks, accelerating failure. The root cause of the ML failure was identified as grain boundary weakening. Measures to mitigate the failure modes include optimisation of the feed distribution system, using corrosion inhibitors during storage, grain boundary-strengthening alloys incorporation, and advanced remanufacturing.