CHARLESTON, W.Va. — Federal Mine Safety and Health Administration officials said Thursday that they told 16 U.S. mining companies with patterns of violating health and safety rules to clean up their acts or face heightened enforcement.

All but two of the companies operate coal mines or processing plants, the majority of them in Kentucky and West Virginia, MSHA said. Also receiving warnings were a Kentucky limestone operation and a Michigan iron ore mine. No Utah mine operators were among those that received warnings Thursday.