CHARLESTON, W.Va.-- Recent surprise inspections show that increased enforcement isn't preventing U.S. coal mines from continuing to violate safety laws, the federal Mine Safety & Health Administration said Tuesday.MSHA inspectors found miners had worked under an unsupported roof at a Tennessee mine, and sections of a West Virginia mine were closed after inspectors found numerous serious violations, the agency said. Serious violations turned up at two Kentucky mines, including an International Coal Group operation that was ordered to stop production last week until its ventilation plan was rewritten."It is appalling that our inspectors continue to find such egregious violations, especially with the explosion at Upper Big Branch still fresh in everyone's minds,'' MSHA director Joe Main said in a statement. "MSHA will continue to target mines with enhanced inspections where conditions merit such actions, particularly at mines that display a disregard to miners' safety and health.''MSHA stepped up enforcement following an explosion that killed 29 men at Massey Energy's Upper Big Branch mine in West Virginia last April. The agency conducted an inspection blitz of 57 problem mines in April and forced six of them to halt production until problems were addressed. The blast was the worst U.S. coal mining disaster since 1970 and remains the subject of civil and criminal investigations.MSHA described the latest raids as a continuation of the crackdown.None of the latest inspections involved Virginia-based Massey Energy, a major U.S. producer that operates dozens of mines in West Virginia, Kentucky and Virginia.Inspectors issued 43 citations to ICG after raiding the company's Classic Mine in eastern Kentucky, MSHA said. ICG was ordered to write a new ventilation plan to fix problems including inoperable dust controls, according to the agency.ICG said it has fixed the violations and production resumed Monday after MSHA approved a new ventilation plan. Some of the citations will be contested, but others will not, the Scott Depot-based company said."ICG also adamantly opposes any implication contained in MSHA's press release that it was necessary to seize mine communications to avoid advance notice of MSHA's inspection,'' the company said. "ICG is committed to operating all of its mines safely and complying with all federal and state mine safety regulations.''MSHA said it had seized control of phone lines at the four mines to prevent people on the surface from alerting workers underground to the presence of inspectors.Massey Energy miners have alleged in congressional testimony that the company used to send out a warning when inspectors arrived.Much of the Maple Eagle No. 1 Mine in Southern West Virginia was shut down, as well, after inspectors issued 31 citations for various violations, MSHA said. The agency categorized 10 of the violations as unwarrantable failures, a designation reserved aggravating conduct deemed worse than ordinary negligence.A spokeswoman for operator Maple Coal had no immediate comment. Nor did Darrell Wagner, owner of the Tri-State One mine in Tennessee. A working telephone number for K&D Mining, operator of the second Kentucky mine cited in the raids, could not be located.