Development of laboratory rock breakage techniques to relate energy and surface area produced by slow compression, drop hammer and stamp mill. A detailed study of laboratory rotary-percussive drilling in a wide range of rocks under different conditions, with the collection of drill cuttings and measurement of the drill parameters. The correlation of drill parameters with rock indices by energy concepts and the developed empirical formula. Field rotary-percussive drilling studies and collection of drill cuttings on the basis of laboratory analysis.