Year of Commercial Production defined as the previous year when specified minerals' commercial production first commences under section 35E(5)(b). Definition of Year of Commercial Production for section 35E(5)(b): it means the previous year in which, due to prospecting operations, commercial production of a mineral or one or more minerals in a group of associated minerals specified in Part A or Part B of the Seventh Schedule begins, creating the temporal trigger for the statute's tax treatment.