Seniority for part time employees shall be determined as follows:
Seniority for part. Time Employees Filling a Temporary Position with Additional Hours A part time employee working additional hours on a temporary basis in excess of four (4) weeks shall be credited with seniority, retro-active to the beginning of the temporary assignment, for all hours worked in the temporary position.
Seniority for part. Time And Casual Employees; Seniority for Part-Time and Casual employees shall be established as of the date upon which he/she commences his/her first shift;