Classification of the mineability of rocks is an integral part of the earthworks occurring in the implementation of engineering works. The existence of degrees of excavation difficulty allows us to specify the needs of mechanisms for earthworks. It is determined according to the old standard CSN 73 3050, and new standard CSN 73 6133. Both standards define the mechanical mechanisms that should be used for each degrees of excavation difficulty. Based on this rock may be the most optimal breakage and extracted without machine selection would have been undersized. That would mean its destruction and inefficient extraction of rocks, or contrary oversizing. On that basis, there would be an unreasonable overpricing earthworks. Into force has already entered a new standard but there are a number of differences in their classification. The publication deals with the evaluation degrees of excavation difficulty, and mechanical mechanisms for earthwork and differences between the two standards, respectively their similarities. It is evident that the old standard represents a very detailed division of soil and rock into seven degrees of excavation difficulty and thus represents a substantially transparent calculation of the total price of earthworks. In contrast, the new standard gives only three degrees of excavation difficulty. This represents a major simplification of the process of classification and subsequent utilization of engineering mechanisms.