The Polish Government wants to use Tauron's economic muscle to bail out a mining company that is not economical to operate.
Why would private investors have any confidence that such companies manipulated by the government are actually operating in a manner designed to benefit their other shareholders?
See source, August 13, 2015.
Note: August 26, 2015: All the state-owned electricity companies have been hit hard by falling stock prices. The Government has also pushed the other company boards to use their company resources to bail out coal (on very unrealistic terms due to union pressure). If successful, the Government will only succeed in also destroying the electricity companies as well as the mines.