Pioneer Group Inc. said it had a loss of $25.2 million in the second  quarter and has discontinued its gold mining operation in Ghana. 
The Boston-based investment company has lost money for several quarters  because of losses from overseas investments, such as the gold mine and a   Russian timber operation. However, its core U.S. mutual fund business has   remained strong.     
  
Pioneer lost $23.5 million in the second quarter from the gold mine  alone and is trying to sell it. The company has said it expects to return   to profitability in the third quarter.   
Pioneer's worldwide assets under management in the quarter rose to  $24.5 billion, from $22.9 billion.