Approaches in forensic engineering of excavating units operating on open pit mines of Serbia

Bucket wheel excavators (BWEs) are a backbone of any power industry that heavily relies on surface exploitation. As such, any failure, breakdown or collapse of the machine or its subsystems poses a serious drawback in the efficiency of an entire mining system, and is strongly reflected on costs in labour, finances, material and downtime, and is also a potential risk to the safety of workers. This, combined with lengthy lifetime of the machines operating in open cast mines of Serbia (measured in decades), places immense value on the avoidance of potentially hazardous problems during all stages of their lifespan, namely the design, manufacture and exploitation phases. Over the past decades, demand for the ever-increasing capacity and efficiency of BWEs has led to failures which may indicate a need for the reassessment of the calculation methods and guides. This paper presents few such cases, along with the discussion about causes, and suggests an approach to dynamic behaviour analysis based on reduced spatial dynamic models of BWEs which enable modal analysis and the analysis of a dynamic response for continuous variation of constructional parameters