All mineral resources are continuously depleting as a result of the exploitation. Their complete depletion, what could be negatively reflected in a number of industrial branches, was taken into consideration during the last decades. In case of the hard coal, its resources were estimated as sufficient for several hundred years. Thus the problem of its resources depletion was neglected, so far. However the economical situation has been changed. Depletion of the hard coal industrial reserves forced necessity of exploitation of the deeper coal seams, as well as those occurring within difficult geological and mining conditions. In the last decade of the former century, by the occasion of coal mines restructuring, the coal resources were re-classified from recoverable into non-recoverable reserves. It resulted in diminution of hard coal recoverable resources. In the year 2011, verification of the hard coal resources occurring within deposits of liquidated mines, including re-calculation of their resources, have been made. This allowed for considerable increase of the volume of hard coal recoverable resources. Sufficiency ratios of the coal resources in the period 2001–2011 for total recoverable resources, recoverable resources of coal of the type 31-33, as well for total industrial reserves and industrial reserves of the coal types 31-33, have been calculated in the present study. It allowed for calculation of averaged exploitation period (in years), with particular attentionpaid to Polish power industry needs. It results from the calculations that, assuming actual exploitation rate, the hard coal reserves are enough for many years. In case of total recoverable resources, the sufficiency ratio of the resources Wzz1 had value from 419 in the year 2003, to 635 in the year 2011, and for coal of the type 31-33, depending on the year, the ratioWzz2 had value from 308 in the year 2002, to 459 in the year 2011. The sufficiency ratio is different if we take under consideration industrial reserves, i.e. part of recoverable resources, which can be considered as an exploitation object in conditions determined by deposit management project, if economical, technical and ecological conditions are satisfied. In this case, total industrial reserves sufficiency was changed from 72 years in the year 2001, to 51 years, in the year 2008, and for industrial reserves of types 31-33 sufficiency ratio decreased from 45 years in the year 2001, to 28 years in the year 2007. It should be emphasized that the analysis in question comprises only and exclusivelly recoverable and industrial reserves of hard coal occuring in Poland. Industrial reserves during the studied period accounted only for several to several tens percent of recoverable reserves, what found reflection in values of sufficiency factors. Predictable losses are also sepatated from industrial reserves in order to compute recoverable reserves, what additionally shortens life of these reserves. Sufficiency of recoveralbe reserves is extremally different in different mines. For example in the mine KWK Kazimierz-Juliusz Sp. z o.o. it amounts for 8 years, in the mine KWK Halemba-Wirek – 77 years (Paszcza 2010). However we may suspect that in the future technological development will allow expoloitation of deposits, which are currently not extracted with respect to technical problems, or with respect to the fact that their industrial handling is not profitable.