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 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 and overlying dolomites and limestones. Deposits of the significant economic importance are those from the vicinities of Lubin in the Fore-Sudetic Monocline. In 2020, there were 2 new documentations of copper ores deposits approved – Nowa Sól in Lubuskie Voivodeship and Sulmierzyce Północ in Wielkopolskie Voivodeship. Both of them are located on the Fore-Sudetic Monocline.
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 ore deposits in Poland are presented on the general and detailed map.
Resources and output
In 2020 anticipated economic resources in the areas of the Fore-Sudetic Monocline and the North Sudetic Basin amounted to 3,025.94 million tonnes of copper ore yielding 49.94 million tonnes of metallic copper and 149.83 thousand tonnes of silver (Table 1). The resources increased by 1,074.74 million tonnes (that is by 55.08%) of ore in comparison with the previous year due to the approval of the 2 new deposits documentations: Nowa Sól (+848.48 million tonnes of ore in C2 category) and Sulmierzyce Północ (+267.17 million tonnes of ore: 147.17 million tonnes in C2 category and 120 million tonnes in D category). The total resources balance resulted also from the ongoing exploitation and losses. In 2020 there was also anticipated sub-economic resources growth – by 3.60% due to the documentation of such resources in Sulmierzyce Północ deposit (+28.87 million tonnes).
The anticipated economic resources of copper ore in deposits made available by operating mines in the area of the Fore-Sudetic Monocline were equal 1,590.98 million tonnes containing 28.99 million tonnes of copper and 84.32 thousand tonnes of silver. It accounted for 52.58% of the total anticipated economic resources and the share dropped by 5.71%. The economic resources of the exploited deposits amounted to 1,117.17 million tonnes of ore and decreased by 40.11 thousand tonnes (3.47%) in comparison with the previous year. The drop was the result of the exploitation and losses.
The anticipated economic resources of non-exploited copper ore 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). However, during the process of 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 for Nowa Sól deposit was equal 2,160 m (the average 1,975 m) and for Sulmierzyce Północ it was 2,060 m (the average 1,825 m).
In 2020, the copper mining gave 29,660 thousand tonnes of copper ore with the copper content at 1.49% and the silver content at 47.98 g/t, yielding 442 thousand tonnes of metallic copper and 1,423 tonnes of silver (Table 2). In comparison with 2019, the output of copper ore decreased by 221 thousand tonnes (0.74%), with the slightly drop of the recovery of metallic copper – by 7 thousand tonnes (1.56%) and metallic silver – by 32 tonnes (2.20%).
In 2020, the KGHM Polish Copper Combine S.A. produced 560.4 thousand tonnes of electrolytic copper, including 413.3 thousand tonnes from their own concentrates and 147.0 thousand tonnes from imported concentrates. Moreover, there was 3,011 kg of gold – both from their own and imported concentrates – produced.
Figures below shows resources and production of copper ores and changes in resources and output of copper in Poland in the years 1989-2020.
The figure given below shows resources and output of silver in the same period.
From the domestic copper ores there are also obtained such elements as: Cu, Ag, Au, Ni, Pb, Se, Re, and the sulphuric acid is obtained as a by-product. The most important, considering the economic value, is the silver recovery. According to the KGHM Polish Copper Combine S.A. information, in 2020 from the copper ore exploited in Poland, there were 1,323 tonnes of Ag, 878 kg of Au, 28.79 thousand tonnes of Pb, 2.06 thousand tonnes of NiSO4, 73.80 tonnes of Se and 9.51 tonnes of Re produced.
The total predicted prognostic resources of copper and silver ores in Poland in the stratabounnd deposits, to the depth of 2,000 m, assessed as the metal content, are equal 10.30 million tonnes, the prospective resources – 15.67 million tonnes, whereas the hypothetical resources – 8.76 million tonnes of Cu*.
Prepared by: Agnieszka Malon, Stanisław Z. Mikulski, Sławomir Oszczepalski, Marcin Tymiński