The changing structure of the raw material base of a mining cluster as a result of over exploitation of rich-in-copper ore mining are asentails a number of changes including conditions and types of operation and the nature of the mining process. The new lyacquiredl and sand mining are as may occupy the horizontal lines (the Sierra Gorda open-pit mine) or vertical ones, in other words, directing into the depths of the earth. In the KGHM Polska Miedź S.A. the process of maintenance is vital, it is not the„added value” init self, but it is an important component in the process of mining. Choosing the right concept of maintenance, for example TPM and taking into account the turbulent operational and mining conditions resulting from e.g. higher machine working environment temperatures decide about the question of their reliability. The diagnosis and prognosis reliability and the influence of conditions upon the underground machinery malfunction ought to be subjected to meas-urement-and-research actions on a scale as frequent as changing exploitation conditions.