In February 2016, Hamilton County Coal LLC, a coal mining concern in southern Illinois, announced to its employees a “temporary layoff” expected to run through July 2016.Hamilton actually hand-delivered copies of a written Temporary Layoff Notice to the workers. The notice, printed on Hamilton letterhead, advised that “due to operational considerations,” the company was placing the employees on an immediate temporary layoff.The notice invited the employees to “return to your at-will employment …