3. lubrication of mill in cement industries. 4. lubrication of mill in steel industries. 5. lubrication of ball mill in fgd (flue gas desulphurization) in thermal power plant. function the lube oil system consists of lube oil tank, 2x100 screw pumps amp; motors, 2x100 filters, and 2x100 oil coolers. the screw pump is used for normal lube oil.