Rescue workers check their gear as they attempt to free Chinese miners trapped underground.<br/> <br />Eighteen of the 28 workers in the coal mine in southwest Guizhou Province were killed in a gas explosion Saturday.<br/> <br />Five miners in critical condition have been rescued.<br/> <br />A local official says gas levels in the mine, as well as debris blocking the tunnel, are delaying efforts to reach five more trapped miners.<br/> <br />China has a record of poor mine safety, with hundreds of accidents each year.<br/> <br />More than 1,000 miners have died this year alone despite the government's efforts to shut down small and illegal operations.
