The people who keep Lima Refinery ticking By Mackenzi Klemann - mklemann@limanews.com Lima Refinery process operators are responsible for operation and maintenance of equipment in the refinery’s chemical and petroleum process areas. The position requires extensive training, which started for the latest cohort of process operators at the Lima Refinery in June. LIMA — Live fire drills. Hazard identification. A broad overview of the Lima Refinery’s operations and the science that makes it work: The latest class of Lima Refinery process operator trainees are undergoing eight weeks of intensive training to learn how the 135-year-old refinery operates.