In this study, quartz, marble, quartzite, and metasandstone with densities 2.65, 2.72, 2.59, and 2.11 t/m 3, respectively, were used as test materials.The origin of the materials as well as their physico-mechanical properties are described in recent study [].The grinding tests were performed in a laboratory 0.204 × 0.166 m (D × L) ball mill that operated at 66 rpm corresponding to N r = 70.4 ...