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 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. 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 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 eposits – 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 2017 anticipated economic resources of copper ore in the areas of the Fore-Sudetic Monocline and North Sudetic Basin amounted to 1,931.95 million tonnes with metallic copper equal 34.59 million tonnes and silver equal 104.47 thousand tonnes (Table 1). The resources decreased by 16.60 million tonnes of ore in comparison with the previous year 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 1,689.33 million tonnes (30.93 million tonnes of metallic copper and 88.04 thousand tonnes of silver). It accounts for about 87.44% of total anticipated economic resources. Economic resources of these deposits amounted to 1,213.75 million tonnes and increased by 70.36 thousand tonnes (6.15%) in comparison with the previous year. The growth was the result of a new deposit development plan (the mining area Gaworzyce – 71.10 thousand tonnes) prepared for Radwanice-Gaworzyce deposit and of a new deposit development plan with recalculated resources prepared for Sieroszowice deposit (6.86 thousand tonnes).
Anticipated economic resources within non-exploited deposits occur mainly at the depth within the range of 1,000 m and 1,250 m, sometimes even at 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 2017, the copper mining gave 31,185 thousand tonnes of copper ore with the copper content at 1.50% and the silver content at 47.8 g/t, yielding 467 thousand tonnes of metallic copper and 1,490 tonnes of silver. In comparison with 2016, the production of copper ore decreased by 799 thousand tonnes (2.50%), with the recovery of metallic copper decreasing by 13 thousand tonnes (2.71%) and the production of metallic silver slightly increasing – by 8 thousand tonnes (0.54%).
In 2017 the KGHM Polish Copper Combine S.A. produced 522.0 thousand tonnes of electrolytic copper, including 358.9 thousand tonnes from their own concentrates, 148.0 thousand tonnes from imported concentrates and 15.1 thousand tonnes from the processed scrap. Moreover, there was 3,648 kg of gold, platinum and palladium and 10.93 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 1989-2017.
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, Pt-Pd, 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 2017 the copper processing was accompanied by a recovery of 1,218 tonnes of silver, 571.7 tonnes of gold, 26.00 thousand tonnes of lead, 1.79 thousand tonnes of nickel sulphate, 73.90 tonnes of selenium, 39.20 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.
Table 1. Copper and silver ores