AUTOGENOUS MILLS AND SEMI-AUTOGENOUS MILLS
In the process of autogenous grinding, the material itself is used as a grinding body. In the course of semi-autogenous grinding, auxiliary grinding media (usually steel balls) are used. Metso's MSI/MPSI mills are ideal for grinding ore or primary crusher products. This line of mills includes models of various sizes and capacities:
- Diameters from 1.8 m to 12.8 m
- A capacity of up to 28 MW
- Synchronous, asynchronous (induction) and wound-rotor motors
- With rolling or plain bearings (hydrodynamic or hydrostatic)

Due to the fact that MPSI mills can process clay and wet material, they are often used to prepare material before grinding in ball mills.