Heavy duty, continuous type ball mill is with three compartment and screen. Replaceable Liners are fixed inside entire mill. Liners material and shape is selected based on material to be grind. Input material is fed in two primary grinding compartments. Large diameter balls for reduce particle size are laying inside first compartment. Material comes into second compartment for further grinding. Small size Balls are laying inside second compartment. Material comes into third for fine grinding. Smaller size media are laying inside third compartment for fine grinding. Diaphragms may place to regulate material level and control retention time. Material is feed and discharged through hollow trunnion at opposite end.