BEIJING, China (AP) -- -- An explosion at a coal mine in northeastern China left 40 dead and another 138 missing, state media reported Monday.A total of 220 miners were underground when the blast occurred late Sunday at the Dongfeng Coal mine in Qitaihe, a city in Heilongjiang province, the official China News Service said, citing the local coal mine safety administration.It did not give the cause of the blast and said it was under investigation.The official Xinhua News Agency said earlier that 30 were dead and 149 were missing.It was not immediately clear why the numbers were different. A man who answered the telephone at the coal mine said officials were too busy to talk and hung up.Xinhua said rescue work was continuing Monday, as managers attempted to figure out exactly how many miners were still underground.The mine is owned by the Heilongjiang Longme Mining (Group) Co., a conglomerate of four state-owned coal businesses in the province, Xinhua said, citing provincial work safety administration officials.Copyright 2005 The Associated Press. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.