Hard coal mining is characterised by the complexity and specificity of problems related to the use of machines. These problems, which occur at the stage of design, construction and production of machines, build up when the machines are being used. The process of most effective hard coal mining is considerably influenced by reliable mining machines. Every downtime due to a failure translates into the effectiveness of the whole mining process. For this reason the mining industry is searching for new methods and tools which would allow it to improve the production (mining) process in a hard coal mine. The article presents one of the quality management tools used in various industry branches – a Pareto chart, by means of which downtimes in the work of cutter-loaders has been analysed. This tool allowed classifying the causes of particular failures as well as showing which of them are the most significant and which should be removed first.