Assessment of remnant life duration for bucket wheel excavators in lignite quarries

In Romania, as well as worldwide, lignite for the production of electrical energy is mainly extracted in quarry conditions. At the present time and for the near future at least, extracting lignite will be done with the help of continuous action excavators, especially with rotary headed excavators with radial digging, that undertake the cutting and the evacuation of the rocks from the baric step and of the lignite. On the mechanized operation lines, the excavator is the leading equipment. The growth in work efficiency of the excavator is conditioned by choosing it according to the concrete conditions of exploitation and in correlation with the other equipments on the operation lines for extracting lignite and mine waste from the coating of the lignite strata, rational intensive and extensive exploitation, adopting a modern and efficient system for doing maintenance, as well as undergoing rehabilitation and modernization processes for maintaining their technical condition at a suitable level. Estimating the duration of safe functioning of an equipment that has a certain degree of risk is a requirement of current legislation. This paper undertakes to present one of the calculus methods that is at the basis of the objective estimation of the remnant life duration of an excavator. (paper)