Tribology of Earthmoving, Mining, and Minerals Processing

Abstract

Earthmoving, mining, and minerals processing each involve frequent, and often severe, mechanical interactions between metals, and between metals and abrasive nonmetallic and metallic materials (i.e., mineral bearing ores). The abrasive nature of ores causes significant wear to extracting, handling, and processing equipment. Consequently, wear in earthmoving, mining, and minerals processing operations results in the removal of large amounts of material from the wear surfaces of scraping, digging, and ore processing equipment. From an energy point of view, material wear of this nature is classified as an indirect tribological loss (Imhoff et al., 1985). Additionally, a significant amount of energy is expended to overcome frictional forces in the operation of all earthmoving, mining, and minerals processing machinery (i.e., a direct tribological loss). However, in these particular processes, wear losses are more than five times those of frictional losses. In general, the amount of material lost from a particular component in these operations, before it becomes unserviceable, is far greater than that which can be tolerated in typical metal-to-metal wear situations (e.g., lubricated bearing-shaft wear couples in machinery). Consequently, much of the equipment used in earthmoving, mining, and ore processing makes use of easily replaceable or repairable, and preferably low-cost, wear components.more » The mechanisms by which metal-to-metal and abrasive wear occurs, and the relationships between material properties and wear behavior, are reasonably well-understood in general terms. However, the specific wear mechanisms/wear material interactions that occur during earthmoving, digging, and the processing of ore are more complex, and depend on the wear material, and on the nature of abrasive, the type of loading, and the environment. As a result of this general knowledge, reliable predictions can be made regarding the performance of particular materials under a range of in-service operating conditions. This knowledge has allowed the rational selection of wear-resistant materials for use as earthmoving, mining, and minerals processing components, and new wear-resistant materials can be designed using our knowledge of the impact and abrasion mechanisms encountered in the day-to-day operation of components used in these operations.« less