Copper and silver ores
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 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 and other metals are mainly concentrated in the Zechstein copper-bearing shales as well as underlying sandstones and overlying dolomites and limestones. Deposits of the largest economic importance are those from the vicinities of Lubin in the Fore-Sudetic Monocline. In 2019, there were 2 new deposits on the Fore-Sudetic Monocline documented – Nowa Sól and Żary (Lubuskie Voivodeship).
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*.
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 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.
The copper deposits area extends in a belt 60 km long and 20 km wide, from Lubin in the south-east to Bytom Odrzański in the north-west. This is actually a single deposit area in which copper ores are currently exploited in the Lubin, Polkowice-Sieroszowice and Rudna mines.
Copper ore deposits in Poland are presented on the general and detailed map.
In 2019 anticipated economic resources of copper ore in the areas of the Fore-Sudetic Monocline and the North Sudetic Basin amounted to 1,951.20 million tonnes yielding 34.75 million tonnes of metallic copper and 103.57 thousand tonnes of silver (table 1). The resources increased by 45.55 million tonnes (that is by 2.39%) of ore in comparison with the previous year due to the new deposit Żary documentation (+76.69 million tonnes of ore). The resources changed also in the result of the ongoing exploitation and losses.
The anticipated economic resources of copper ore in deposits made available by operating mines in the area of the Fore-Sudetic Monocline were equal 1,631.89 million tonnes containing 29.81 million tonnes of copper and 87.14 thousand tonnes of silver. It accounted for 58.29% of the total anticipated economic resources and the share dropped by 28.98%. the economic resources of the exploited deposits amounted to 1,157.28 million tonnes and decreased by 31.23 thousand tonnes (2.63%) 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). In 2019, there was Żary deposit documented and its resources were established in category D to be equal 76.69 million tonnes of ore. Unfortunately, the information on the detailed location and the deposit parameters, described in the documentation, is not publically available due to the decision of the Minister of the Environment.
In 2019, the copper mining gave 29,881 thousand tonnes of copper ore with the copper content at 1.50% and the silver content at 48.69 g/t, yielding 449 thousand tonnes of metallic copper and 1,455 tonnes of silver (table 2). In comparison with 2018, the output of copper ore decreased by 371 thousand tonnes (1.23%), with the recovery of metallic copper decreasing by 3 thousand tonnes (0.66%) and the output of metallic silver dropped by 16 tonnes (1.09%).
In 2019, the KGHM Polish Copper Combine S.A. produced 565.6 thousand tonnes of electrolytic copper, including 418.3 thousand tonnes from their own concentrates and 147.3 thousand tonnes from imported concentrates. Moreover, there was 3,225 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 1989-2019.
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 2019 from the copper ore exploited in Poland, there were 1,400 tonnes of Ag, 674 kg of Au, 28.51 thousand tonnes of Pb, 1.99 thousand tonnes of NiSO4, 75.76 tonnes of Se and 8.34 tonnes of Re produced.
Prepared by: Agnieszka Malon, Stanisław Z. Mikulski, Sławomir Oszczepalski, Marcin Tymiński
* Oszczepalski S., Markowiak M., Chmielewski A., 2020 - Rudy miedzi i srebra (copper and silver ores). In: Bilans perspektywicznych zasobów kopalin Polski wg stanu na 31.12.2018 r. (eds. Szamałek K., Szuflicki M., Mizerski W.): 127-151. PIG-PIB, Warszawa.