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 as well as 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 high economic value.
Polish copper ores belong to the stratabound type. The deposits are situated in the areas of the Fore-Sudetic Monocline and North Sudetic Basin in the Lower Silesia and related to the Zechstein Kupferschiefer formation. Minerals containing copper and other metals are mainly concentrated in the copper-bearing shales as well as underlying sandstones and overlying dolomites. Deposits of the largest economic importance are those from the vicinities of Lubin in the Fore-Sudetic Monocline.
The copper-bearing series comprises three separate lithological layers: sandstones at the base, clay-marly or dolomitic shales and dolomitic limestones in upper part. The strongest copper mineralization occurs 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, Żary Pericline and North Sudetic Basin prognostic resources amounted to 22.7 million tonnes of copper (5 regions with the area of 253 km2, maximum depth of 2,000 m), perspective resources amounted to 5.94 million tonnes of copper (7 regions with the area of 114 km2, maximum depth of 2,000 m) and hypothetical resources to 229.1 million tonnes - including 42.7 million tonnes to the depth of 2,000 m and 186.4 million tonnes below 2,000 m depth (11 regions with the area of 1,830 km2)*.
In 2015 anticipated economic resources of copper ore within the areas of the Fore-Sudetic Monocline and North Sudetic Basin amounted to 1,976.04 million tonnes with metallic copper amounted to 35.57 million tonnes and silver amounted to 107.46 thousand tonnes (table 1). The resources increased by 239.16 million tonnes in comparison with the previous year. It was due to the documentation of a new deposit – Radwanice-Gaworzyce (+344.30 million tonnes). The resources drop was caused by the crossing three deposits out from “The balance…”: Gaworzyce (-54.39 million tonnes), Radwanice-Wschód (-5.95 million tonnes) and Radwanice-Zachód (-18.58 million tonnes). All of them were subsumed into the Radwanice-Gaworzyce area. The resources decline also due to the exploitation and losses.
Anticipated economic resources of copper ore in exploited deposits in the area of the Fore-Sudetic Monocline are equal 1,389.12 million tonnes (27.18 million tonnes of metallic copper and 81.95 thousand tonnes of silver) – it accounts for about 70% of total anticipated economic resources. Economic resources of these deposits amounted to 1,162.24 million tonnes.
In 2015, copper mining gave 31,568 thousand tonnes of copper ore (with copper content at 1.52% and silver content at 44.6 g/t) yielding 479 thousand tonnes of metallic copper and 1,407 tonnes of silver (table 2). In comparison with the year 2014, production of copper ore slightly increased (by 1.8%), with recovery of silver and production of metallic copper increasing by 1.7% and 1.3% respectively.
In 2015 the KGHM Polish Copper Combine S.A. produced 574.3 thousand tonnes of electrolytic copper, including 420.5 thousand tonnes from their own concentrates and 153.8 thousand tonnes from imported concentrates. Moreover, there were 2,703 kg of gold and 9.17 tonnes of rhenium – 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 1989-2015.
The figure given below shows resources and output of silver in the same period.
Other metals recovered from copper ores include Ag, Au, Ni, Pb, Pt-Pd, Se, Re and sulfuric acid as a by-product. Recovery of silver is of the largest economic importance. According to the data provided by the KGHM Polish Copper Combine S.A., in 2015 the copper processing was accompanied by recovery of 1,283 tonnes of silver, 431 tonnes of gold, 29 thousand tonnes of lead, 2.97 thousand tonnes of nickel sulphate, 86.98 tonnes of selenium, 137 kg of Pt-Pd concentrate and sulfuric acid and copper sulfides.
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.