"The Proven and Probable Mineral Reserves contained within KGHM's mining concessions, as of 31 December, 2011, amounted to 1,181 Mt at grades of approximately 1.58 percent Cu and 48 g/t Ag, containing 18.6 Mt of copper and 1,800 Moz of silver,"

Micon consultancy said in the report released on Monday.

Poland's state-controlled miner is currently the world's ninth-largest copper producer, with output at 527,000 tonnes, following its acquisition last year of Canadian rival Quadra FNX for C$3 billion ($3 billion).