Mark Drummond, chancellor of the Los Angeles Community College District, took an unexpected leave last month and on Thursday announced that he was resigning,  effective July 31. Drummond is midway through a four-year contract and no reason was given for his sudden departure. Drummond was chancellor of the district from 1999 to 2004 and then left to become chancellor of the state's community college district. He returned in 2007, saying that he really wanted to return to the Los Angeles job. A spokesman for the district declined to elaborate on the statement except to say that the decision was "mutual" between the chancellor and the board. In the announcement, Drummond noted the successful passage of a series of bond measures that have provided $5.7 billion for renovations and construction of the nine campuses in the district.