* Semi-autogenous (SAG) grinding is a grinding process carried out with small amount of ball charge (4-15%) unlike ball mills and with the help of bigger parts crumbling the smaller parts of ore.
* To achieve this type of grinding, SAG mills with large diameter and short length have been developed to take advantage of the kinetic energy of the free falling coarse particles.
* SAG mills are primarily preferred in gold, copper, platinum and silver mines as well as lead, zinc and nickel etc. mines
* Majority of large tonnage ore plants uses SAG mills in their systems.
ADVANTAGES OF SEMI AUTOGENOUS (SAG) MILLS
* In conventional systems, the reduction ratio of the grain size is distributed to the crushers. The material must be passed through multiple number of crushing / sieving steps in order to be reduced to the milling (10-12 mm) size.
* Crushing and screening of clayey and adhesive materials are very difficult in systems using multi-stage crushing lines. The system is constantly clogged and encountered problems due to seasonal conditions, requiring additional measures. (Such as the stocking of broken material in summer)
* SAG mills are the machines with the highest reduction rate which performs crushing, grinding and washing together. It offers a much higher reduction ratio than 3-stage crushing and screening system.
* Feeding material in the dimension of 200-300 mm, is reduced to d100: 2 mm and below. This capability increases the efficiency of the ball mill while reducing the circulating load of the system.