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. Deposits of the significant economic importance are those from the vicinities of Lubin and Polkowice in the Fore-Sudetic Monocline. In 2021, there was 1 new documentation of copper and silver ores deposits approved – Mozów in Lubuskie Voivodeship 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 and silver ores deposits in Poland are presented on the general and detailed map.
Resources and output
As of 31.12.2021, anticipated economic resources of copper and silver ores in the areas of the Fore-Sudetic Monocline and the North Sudetic Basin amounted to 3,210.83 million tonnes of ore yielding 53.34 million tonnes of metallic copper and 153.28 thousand tonnes of silver (Table 1). The resources increased by 184.89 million tonnes (that is by 6.11%) of ore in comparison with the previous year due to the approval of 1 new deposit documentation: Mozów (+223.59 million tonnes of ore in C2 category). The total resources balance resulted also from the ongoing exploitation and losses. In 2021 there was also anticipated sub-economic resources growth – by 1.16% due to the documentation of such resources in the Mozów deposit (+9.59 million tonnes).
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 1,552.28 million tonnes containing 28.11 million tonnes of copper and 82.05 thousand tonnes of silver. It accounted for 48.35% of the total anticipated economic resources and the share dropped by 4.23%. The economic resources of the exploited deposits amounted to 1,081.18 million tonnes of ore and decreased by 35.99 thousand tonnes (3.22%) in comparison with the previous year. The drop was mainly the result of the exploitation and losses.
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 2021, the copper-silver ores mining gave 30,000 thousand tonnes of ore with the copper content at 1.48% and the silver content at 50.73 g/t, yielding 443 thousand tonnes of metallic copper and 1,522 tonnes of silver (Table 2). In comparison with 2020, the output of ore increased by 340 thousand tonnes (1.15%), with the recovery growth both for metallic copper – by 1 thousand tonnes (0.23%) and for metallic silver – by 99 tonnes (6.96%).
According to the report published by the Capital Group KGHM Polish Copper Combine S.A., in 2021 the mining production of copper in the concentrate (within the KGHM Polish Copper Combine S.A.) amounted to 391.3 thousand tonnes. The smelter production of electrolytic copper amounted to 577.6 thousand tonnes in total, including 381.4 thousand tonnes from own concentrates. Moreover, in 2021, there was 2,529 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 1989-2021.
The figure given below shows resources and output of silver in the same period.
From the domestic copper-silver ores there are also obtained such elements as: Cu, Ag, Au, Pb, Ni, Se, 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 2021 from the copper-silver ores exploited in Poland, there were 1,332 tonnes of Ag, 768 kg of Au, 29.43 thousand tonnes of Pb, 1.97 thousand tonnes of NiSO4, 66.21 tonnes of Se and 9.25 tonnes of Re produced.
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, the prospective resources – 15.67 million tonnes, whereas the hypothetical resources – 8.76 million tonnes of Cu*.