Rock Crushing Rule of Thumb
· Impact crushers (rotary or hammer mills) have the capacity for high reduction ratios (up to 40:1), but are rarely applied to hard rock mines. Since they depend on high velocities for crushing, wear is greater than for jaw or gyratory crushers. Hence, they should not be used in hard rock mines that normally have ores containing more than 15% silica (or any ores that are abrasive). Source: Barry ...