Federated Mutual Insurance Co. insisted that the work-product privilege protected it from having to turn over “internal coverage evaluations” during discovery in its declaratory judgment case against Coyle Mechanical Supply. And Federal argued that the evaluations weren’t relevant because the crucial issue — whether the damages claimed by Prairie State Generating Co. in a tort suit against Coyle were caused by an “occurrence,” as defined in the liability policy Federated sold to Coyle — was a question of law.Prairie State …