The phrase "separate mailing" means sending something in a different package or envelope, typically to be delivered separately from other items. Full definition
On a rotation basis, performs all of the following duties: loads mail onto automated equipment, culling out non-processable items; enters sort plan and starts equipment; monitors flow of mail to ensure continuous feed; sweeps separated mail from bins stackers; and stops equipment when distribution run or operation is completed. (jobhero.com)
Load mail onto automated equipment, culling out non-processable items; enters sort plan and start equipment; monitors flow of mail to ensure continuous feed; sweep separated mail from bins / stackers; and stops equipment when distribution run or operation is completed. (jobhero.com)
Separated mail into pigeon holes of mail racks according to mail center and organizational departments (jobhero.com)