A mill head assembly apparatus utilizing centrifugal hydrodynamic force to circulate lubrication oil while retaining the lubricant without the need for a replaceable (contact-type) seal, the apparatus comprising a set of stationary components including a trunnion, an oil ring, a bearing-retainer, and a collector ring and rotating components including a housing, a pump ring, and a baffle-ring, front and rear bearing means. The oil ring receives and circulates the lubrication oil to the bearing means, the housing is disposed with a plurality of housing passages to re-circulate the lubrication oil, and the forward and rear rotating interfaces to retain the lubrication oil within the front and rear mill head assembly. Potential lubrication oil leakage is retained and re-circulated back to the collector ring by close-tolerance seal means.