Poland implemented a mining tax in 2012. KGHM expects to pay around 1.4 billion zlotys ($355 million) worth of mining levies this year, equal to around 58 percent of the company's 2014 net profit.

Shares in KGHM have tumbled 36 percent since Poland's prime minister announced plans on Nov. 18 to introduce a mining tax which is targeted to contribute 1.8 billion zlotys ($530 million) to the ...