Abstract

The effective operating time (EOT) of the equipment in an open pit mine determines the capacity of the mine. Clearly, EOT is only a part of the total calendar time, which also includes various down times or non-productive times, caused by different factors. Therefore, it is important to analyze the components of calendar time. A logical prerequisite for such an analysis as well as for predicting the capacity of a projected mine is a plausible model of calendar time structure and clear definitions of its components. We present here such a model, which is based on a comparative study of calendar time structure models used by several mining companies. Furthermore, we discuss the proportionality of downtimes and non-productive times to the EOT. This is fundamental for the prediction of the capacity of open-pit mines in projection, rationalization or expansion.