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.
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 map.
In the areas of the Fore-Sudetic Monocline, the Żary Pericline and the North Sudetic Basin prognostic resources assessed for 6 selected regions – designated within the nearest surroundings of the documented deposits – of a total area equal 132 km2 amount to 10.3 million tonnes of copper (at the depth to 1,700 m), perspective resources within 4 selected regions of a total area equal 199 km2 amount to 15.7 million tonnes of copper (at the depth to 1,900 m) and hypothetical resources within 28 regions of a total area equal 1,414 km2 amount to 152.8 million tonnes, including 8.2 million tonnes at the depth to 2,000 m and 144.6 million tonnes at the depth below 2,000 m*.
In 2018 anticipated economic resources of copper ore in the areas of the Fore-Sudetic Monocline and the North Sudetic Basin amounted to 1,905.65 million tonnes yielding 34.04 million tonnes of metallic copper and 103.28 thousand tonnes of silver (table 1). The resources decreased by 26.30 million tonnes (1.36%) of ore in comparison with the previous year due to the exploitation and losses.
Anticipated economic resources of copper ore in deposits made available by operating mines in the area of the Fore-Sudetic Monocline are equal 1,663.03 million tonnes containing 30.38 million tonnes of copper and 86.85 thousand tonnes of silver. It accounts for 87.27% of total anticipated economic resources. Economic resources of the exploited deposits amount to 1,188.51 million tonnes and decreased by 25.24 thousand tonnes (2.08%) in comparison with the previous year. The drop was the result of the exploitation and losses.
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 (anticipated sub-economic due to the depth). Their standalone development would be very difficult but possible when using the providing excavations from existing neighboring mines or by a new mines construction.
In 2018, the copper mining gave 30,252 thousand tonnes of copper ore with the copper content at 1.49% and the silver content at 48.6 g/t, yielding 452 thousand tonnes of metallic copper and 1,471 tonnes of silver (table 2). In comparison with 2017, the output of copper ore decreased by 933 thousand tonnes (2.99%), with the recovery of metallic copper decreasing by 15 thousand tonnes (2.99%) and the production of metallic silver slightly dropped by 19 tonnes (1.28%).
In 2018 the KGHM Polish Copper Combine S.A. produced 501.8 thousand tonnes of electrolytic copper, including 385.3 thousand tonnes from their own concentrates and 116.5 thousand tonnes from imported concentrates. Moreover, there was 2,587 kg of gold, platinum and palladium and 9.09 tonnes of renium – 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 1989-2018.
The figure given below shows resources and output of silver in the same period.
Other metals recovered from copper ores include Cu, Ag, Au, Ni, Pb, Se, Re and sulfuric acid as a by-product. The recovery of silver is of the largest economic importance. According to the data provided by the KGHM Polish Copper Combine S.A., in 2018 the copper ore processing was accompanied by a production of 1,189 tonnes of silver, 523 kilograms of gold, 27.21 thousand tonnes of lead, 1.73 thousand tonnes of nickel sulphate and 66.36 tonnes of selenium.
Prepared by: Agnieszka Malon, Stanisław Z. Mikulski, Sławomir Oszczepalski, Marcin Tymiński
*Oszczepalski S., Speczik S., 2011 - Rudy miedzi i srebra. In: Bilans perspektywicznych zasobów kopalin Polski wg stanu na 31 XII 2009 r. (ed. S. Wołkowicz, T. Smakowski, S. Speczik): 76-93. PIG-PIB, Warszawa.
Table 1. Copper and silver ores