text: Sepro Tyre Driven Grinding Mills are designed for small and medium capacity grinding applications, specifically small tonnage plants, regrinding mills, reagent prep and lime slaking. Sepro Pneumatic Tyre Driven (PTD) mills provide an alternative to standard trunnion drive systems. The drive consists of multiple gears boxes and electric motors directly connected and controlled through an AC variable frequency drive. Shell supported mills such as the Sepro PTD mills minimize stress on the mill shell by spreading the power drive over the full length of the mill.  Sepro Mills are suitable for ball, rod and pebble charges and are available with overflow or grate discharge to suit the application. Shell supported mills such as the Sepro PTD Grinding Mills minimize stress on the shell by spreading the power drive over the full length of the unit.