Magnetic form cushion broken balls and magnetic minerals of20~30mm, they areabsorbed so firmly on the metal protective shell surfaces that avoid directconflicts between the ball and its materials with surface of the magnetic lining plate. Magnetic lining plate has a longlife due to the work surface is protected by ore bed. Now Sichuan gaodete technology technology co., ltd is theonly company in southwest China engaged in the research anddevelopment of magnetic lining project.