Resources and output
Four areas of Zn-Pb ore deposits are recognized in the Silesian-Cracow region: Chrzanów, Olkusz, Bytom and Zawiercie regions. In 2020, the exploitation carried out so far of ores from the Klucze I, Olkusz and Pomorzany deposits in the Olkusz region was ended. The “Olkusz-Pomorzany” mine was put into liquidation, and the Minister of Climate and Environment on 15th of January 2021 decided to extinguish an exploitation concession for above mentioned deposits as of 1.01.2021. The Zn-Pb deposits of the Bytom and Chrzanów regions are of the historical importance only. The deposits have been exhausted in the result of the exploitation conducted since the Middle Ages and now comprise some anticipated sub-economic resources of mainly oxide ores (the so-called “calamines”) with minor participation of sulfide ores. The exploitation of deposits of the fourth region (Zawiercie) has not started up to now. The location of Zn-Pb ores deposits in Poland are presented on the general and detailed maps.
The Zn-Pb concentrations accompanying the sulfide copper and silver ores occur in the Zeschstein copper-silver deposits in the Fore-Sudetic Monocline. The average lead contents are only in the range of 0.05-0.3%, therefore the lead recovery is possible only in the course of a copper concentrate treatment in smelters. According to the data provided by the KGHM Polish Copper S.A., in 2021 the copper and silver processing was accompanied by a recovery of 29.43 thousand tonnes of lead.
The most important prospects for the Zn-Pb ores resources growths are connected with the Silesian-Cracow region – where in the carbonate rocks of the Middle Triassic and the Devonian age the sulfide Zn-Pb mineralization of the MVT type occur. As of the 31.12.2018, in the Olkusz region, the estimated prognostic resources are equal about 35 million tonnes of the Zn-Pb ores, whereas in the Zawiercie region – about 25 million tonnes of the Zn-Pb ores*. The Zn oxide ores (the calamines), occurring in the Silesian-Cracow region have not been exploited for many years and their prognostic resources in the abandoned deposits have to be verified and assessed according to the current limit values of the parameters that define the deposit and its boundaries.
Estimations of Zn-Pb ores resources in the Silesian-Cracow region have been changing markedly during the last several dozen years. These changes resulted on one hand from an intense exploration and exploitation of the deposits and on the other – from a crossing out the resources of zinc oxide ores (the calamines) from the official records of domestic resources of mineral raw materials. The decision to cross out the resources was connected with high occupational and environmental hazards associated with a technology used at that time in the oxide ore processing. The problems in the technology were finally solved. Therefore, it appeared necessary to introduce special criteria for the classification of oxide ore resources not meeting those of the sulfide ores. Such separate criteria for Zn oxide ore resources were established by the Regulation of the Minister of the Environment on classification for mineral reserves and resources of 9th January 2007. According to the Geological and Mining Law obliging since the 1st of January 2012 there are separated criteria for sulphide and oxide ores deposits called “the limit values of the parameters that defines the deposit and its boundaries”.
Table 1 shows resources and the current state of exploration and development of Zn-Pb deposits.
The anticipated economic resources of Zn-Pb ores as of 31.12.2021 amounted to 90.98 million tonnes of ore yielding 3.85 million tonnes of zinc and 1.43 million tonnes of lead. The resources both of ore and of metallic zinc and lead have not changed due to the lack of the output. In 2021, as the result of the finished exploitation, there was a new geological documentation (supplement) approved for the Klucze I deposit – it did not change the resources volume in comparison with 2020. The resources remained in accordance with the last information on the resources changes sent to the PGI-NRI by the concession holder.
The majority of the anticipated economic resources of Zn-Pb ores is documented in C2 category (52.69%) and C1 category (25.73%), less resources in A+B category (13.62%) and in D category (7.95%).
As of 31.12.2021, in the registry there were not any economic resources indicated due to the extinction of exploitation concessions for the following deposits: Klucze 1, Olkusz and Pomorzany.
In 2021, there was not any output of the Zn-Pb ores recorded in Poland.
The figure given below shows changes in resources and production of zinc and lead ores in Poland in the years 1989-2021.
The figure below shows changes in resources and output of zinc in Poland in the years 1989-2021.
The figure below shows changes in resources and output of lead in Poland in the years 1989-2021.
Prepared by: Agnieszka Malon, Marcin Tymiński, Stanisław Z. Mikulski