Crushing circuits and control
In recent years, efforts have been made to improve crusher efficiency in order to reduce capital and oper- ating costs. Automatic control of crushing circuits
is increasingly used, larger crushers have been constructed, and mobile crushing units have been used, which allow relatively cheap ore transporta- tion by conveyor belts rather than by trucks to a fixed crushing station (Kok, 1982; Woody, 1982; Gresshaber, 1983; Frizzel, 1985). A mobile crusher is a completely self-contained unit, mounted on a frame that is moved by means of a transport mechanism in the open pit as mining progresses. Mobile units typi- cally use jaw, hammer, or roll crushers, fed directly or by apron feeders, at rates of up to 1000 t h -~ . Some