General information and occurrence
Copper ore deposits occur in several countries throughout the world and under various geological conditions. The most important are porphyry copper deposits, then the sediment-hosted stratabound copper deposits and the exhalative-sedimentary ones (massive pyrite ores). Moreover, there are other igneous copper ores of various types, generally characterized by smaller resources but sometimes of a high economic value.
Polish copper and silver ores belong to the stratabound type. The copper and silver ores deposits are situated in the areas of the Fore-Sudetic Monocline and the North Sudetic Basin in the Lower Silesia and related to the Zechstein Kupferschiefer formation (sediment-hosted stratiform copper deposits – SSC, Kupferschiefer-type). Minerals containing copper with admixture of other metals are concentrated in the Zechstein copper-bearing shale as well as underlying sandstones of white-liegendes and overlying Zechstein dolomites and limestones. Main deposits, of the significant economic importance, are those from the vicinities of Lubin, Polkowice and Głogów in the Fore-Sudetic Monocline. In 2022, there was 1 documentation of a new copper and silver ores deposit approved, located on the Fore-Sudetic Monocline: Retków-Grodziszcze (Dolnośląskie Voivodeship). The deposit was allocated from the most detailed documented (in C1 category) parts of the Głogów and Retków deposits.
The copper-bearing series comprise 3 separate lithological layers: sandstones at the base, clay-marly or dolomitic shales in the middle and dolomitic limestones in the upper part. The strongest copper mineralization occur in the gray-black clay shales which, therefore, are named the Copper-bearing Shales. The major copper minerals of the ores include: chalcocite (Cu2S), bornite (Cu5FeS4) and chalcopyrite (CuFeS2). They are accompanied by numerous other minerals of copper, silver (including native silver), lead, zinc, cobalt and nickel.
Copper and silver ores deposits in Poland are presented on the general and detailed map.
Resources and output
As of 31.12.2022, anticipated economic resources of copper and silver ores in the areas of the Fore-Sudetic Monocline and the North Sudetic Basin amounted to 3,562.23 million tonnes of ore yielding 57.33 million tonnes of metallic copper and 166.29 thousand tonnes of silver (Table 1). The resources increased by 351.40 million tonnes (that is by 10.94%) of ore in comparison with the previous year due to: approval of documentation for the Retków-Grodziszcze deposit (+416.02 million tonnes of ore in C1 category); approval of new documentations with recalculated resources (supplements) for the Nowa Sól deposit (-2.22 million tonnes) and Retków deposit (-17.41 million tonnes); the exploitation (-30.45 million tonnes) and exploitation losses. As a result of approval of above mentioned supplements and a new documentation with recalculated resources (with only anticipated sub-economic resources assessed) for the Głogów deposit, in 2022 the amount of the anticipated economic resources decreased by 216.95 million tonnes (25.83%).
The anticipated economic resources of copper and silver ores in deposits made available by operating mines in the area of the Fore-Sudetic Monocline were equal 1,507.30 million tonnes of ore containing 27.46 million tonnes of copper and 79.61 thousand tonnes of silver. It accounted for 42.31% of the total anticipated economic resources and the share dropped by 6.04%. The economic resources of the exploited deposits amounted to 1,041.79 million tonnes of ore and decreased by 39.39 thousand tonnes (3.64%) in comparison with the previous year. The drop was mainly the result of the exploitation, exploitation losses and approval of a new deposit development plan (supplement) for the Rudna deposit.
The anticipated economic resources of non-exploited copper and silver ores deposits occur mainly at the depth within the range of 1,000 m and 1,250 m, sometimes even to 1,450 m (considered till now as the anticipated sub-economic due to the depth). During the process of the Mozów, Nowa Sól and Sulmierzyce Północ deposits documentation, the criteria of the limit values of the parameters that define the copper ore deposit differed from the ones included in the Regulation of the Minister of the Environment i.a.: the maximum depth of the deposit bottom was increased. Finally, the depth was assumed as follows: for the Mozów deposit – 2,537.00 m (the average 2,471.51 m); for the Nowa Sól deposit – 2,160.53 m (the average 1,975.12 m); for the Sulmierzyce Północ deposit – 2,059.59 m (the average 1,824.92 m).
In 2022, the copper-silver ores mining gave 30,452 thousand tonnes of ore with the copper content at 1.45% and the silver content at 50.19 g/t, yielding 443 thousand tonnes of metallic copper and 1,533 tonnes of silver (Table 2). In comparison with 2021, the output of ore increased by 452 thousand tonnes (1.51%), with the recovery of metallic copper on the same level and that of metallic silver increasing by 11 tonnes (0.72%).
According to the report published by the Capital Group KGHM Polish Copper Combine S.A., in 2022 the smelter production of electrolytic copper amounted to 586.0 thousand tonnes in total, including 381.5 thousand tonnes from own concentrates and 204.5 thousand tonnes from imported inputs. The production of electrolytic copper in comparison with 2021 grew by 8.4 thousand tonnes (1.5%) as a result of increasing imported inputs supply. Imported inputs are in the form of scrap, copper blister and concentrate and allow to effective use of existing technological capabilities of the company. In 2022, the smelter production of silver amounted to 1,298 tonnes – that is by 33.8 tonnes less than in 2021 (the production of Ag in KGHM comes only from its own input). Moreover, in 2022, there were 5,520.87 kg of precious metals produced (TPM – Total Precious Metals – gold, platinum and palladium) both from their own and imported concentrates.
Figures below shows resources and production of copper ores and changes in resources and output of copper in Poland in the years 1989-2022.
The figure given below shows resources and output of silver in the same period.
From the domestic copper-silver ores there are also recovered such elements as: Cu, Ag, Au, Pb, Ni, Se and Re, and the sulphuric acid is obtained as a by-product. The most important, regarding an economic value, is the copper and silver recovery. According to the KGHM Polish Copper Combine S.A. information, in 2022 from the copper-silver ores exploited in Poland, apart from Cu, there were also produced: 1,298 tonnes of Ag, 769 kg of Au, 28.77 thousand tonnes of Pb, 2.24 thousand tonnes of NiSO4, 81.71 tonnes of Se and 6.31 tonnes of Re.
The total predicted prognostic resources of copper and silver ores in Poland in the stratabound deposits, to the depth of 2,000 m, assessed as the metal content, are equal 10.30 million tonnes of Cu, the prospective resources – 15.67 million tonnes of Cu, whereas the hypothetical resources – 8.76 million tonnes of Cu; regarding silver, the resources volumes are: 37.34 thousand tonnes of Ag, 27.72 thousand tonnes of Ag and 17.92 thousand tonnes of Ag, respectively*.