Deposits in the form of seams are most often exploited by means of mechanised longwall systems. Hard coal seams of various thicknesses are mined by plowing and shearer complexes. Both solutions are commonly used in Polish and global mining. Mechanised longwall systems consist of many machines, the most important of which are the mining machine, powered support, armoured face conveyor and beam stage loader. The article is concerned with the failure frequency of longwalls equipped with plow and shearer longwall systems in one of the Polish hard coal mines. The analysis covers a period of 13 months of the mine’s operation, during which 2,589 failures were recorded. It was carried out for all longwalls exploited in that period, i.e. five plow and five shearer ones, operating in six different sections. In the analysed period, these longwalls worked for an average of 150 days, and a total of 1,484 days. The analysis takes into account the basic division of failures used in the mining branch, i.e. mining, electrical and mechanical failures. The plow and shearer complexes were analysed separately, taking into account the failure category for all devices. A comprehensive analysis of the failure rates has revealed that the failure rate of longwalls equipped with plow complexes is noticeably higher than that of shearer ones. Moreover, it has been demonstrated that mining failures are prevalent in the analysis of both the number of failures and the average duration of failures.