Poland has lined up a third investor for one of its troubled state-run coal mining groups, KHW, to limit the amount of money Weglokoks and Enea need to invest, the country’s deputy energy minister said on Tuesday. KHW has found itself in deeper trouble than thought since six Polish state-run firms agreed to stump up $620-million to save the European Union’s largest coal miner Kompania Weglowa (KW) from bankruptcy two months ago.