Specific energy as a productivity and wear performance indicator for mining equipment


Mr Tim Grain Joseph

The mining industry most commonly uses specific energy as a KPI relative to production, defined as the energy per unit mass of volume moved, whether through drilling, blasting, excavation or haulage. What is not clearly understood that in units of Energy per unit Volume we are actually expressing a scalable constant associated with the specific mining sub-activity in a given geology, such that Nm/m3 is actually units of Pa. This also applies to ground engaging tool (GET) wear such as experienced by bits, picks, teeth, rippers, blades associated with drills, continuous miners, excavator buckets, and dozer implements to name but a few. In this latter case specific energy is defined as the energy per unit volume wear material loss, also with units of Pa; which is also directly proportional to the Vickers’ hardness of the wear material. This paper outlines the application of specific energy as a productivity and wear protection KPI to identify opportunities for mining operations to both understand and account for the energy expended in mining (identifying a minimum energy option) and selecting the most appropriate wear protection materials for GET. Keywords: excavating, crushing, dozing, specific energy, abrasive wear, Vickers’ hardness, wear material selection, KPI