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Polish sediment-hosted stratiform copper deposits associated with Zechstein sediments are one of the country’s most valuable natural resources and the basis for its copper industry. The paper presents the history of their research and current exploration. Although documented deposits and their identified resources are described and characterized, much attention is paid to areas located outside of them, including those where geological exploration is currently underway. The gradual depletion of shallow Cu–Ag reserves in the Lubin-Sieroszowice district and elsewhere in the world requires exploration for deeper-seated deposits. To expand resources, time span and scale of copper production in Poland, exploration and definition of new prospects is of great importance. Thirty-five prospective areas with hypothetical and speculative resources have been delineated in SW Poland, including the most prospective areas adjacent to the Cu–Ag Lubin-Sieroszowice deposit. The paper also focuses on those parts of the Fore-Sudetic Monocline where new copper deposits were recently identified. Their resources are described along with the methodology of establishing their boundaries, which differs from recommended Polish threshold parameters not taking into account the depths exceeding 1500 m. Intelligent modern mining and ore processing technologies are considered as a prerequisite for future profitable development of deposits at deeper levels.

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The most significant copper reserves in Poland are confined to sediment-hosted stratiform Kupferschiefer-type deposits that occur at the Zechstein/Rotliegendes transition in the Fore-Sudetic Monocline and North-Sudetic Trough. Gradual depletion of shallow reserves results in exploitation of deeper beds. Latest studies of numerous drill hole cores strongly indicate that the Kupferschiefer series in SW Poland (outside the Lubin-Sieroszowice Copper District) contains a very large volume of prognostic, prospective and hypothetical resources. 38 prospects have been delineated (including 6 areas with prognostic resources, 4 with prospective resources, and 28 areas with hypothetical resources). Among the prospective areas, particular attention is paid to the areas adjacent to the existing mines of Lubin-Sieroszowice copper district, with prognostic resources (Białołęka, Grochowice, Kulów, Luboszyce). Also the areas: Nowiny, Żarków and Mirków are interesting due to accessible depths, Sulmierzyce and Janowo areas due to considerable resources and reasonable depth, and Mozów area – because of high Cu-Ag grading mineralized body with credible continuation to south east through Jany and Grochowice prospects, towards the Lubin-Sieroszowice mining district. It can be estimated that approximately 179 million tons Cu and 346 thousand tons Ag concentrated as potential resources in prospects of SW Poland for future mining, which will be possible, when geological and technological barriers (depth, temperature, oil and gas) will meet economic trends in the world market. Expected progress in underground mining at depths exceeding 1500 m (a depth limit for economic categories) will make this approach effective and technically possible. Additional six prospective areas have been delineated in the contact zone between Upper Silesia and Małopolska blocks, where porphyry-type Mo-Cu-W mineralization (locally with skarns) occurs within porphyry/granitoid rocks and Ediacaran, Ordovician, Silurian, Devonian and Carboniferous metasediments and other sedimentary formations. It should be noted, however, that irregular network of examined drill holes tended to simplify the ranges of prospects and to overestimate resource evaluation. Extensive deep exploration drilling is required to verify resource potential of granted and applied exploration licenses in several targets. The long-term challenges require new solutions for mining industry of the future and industrial market within the EU, to enable the reindustrialization of Europe.

Drill core samples from the Kupferschiefer of Poland were collected throughout the Zechstein basin. The samples included oxidized Kupferschiefer from Rote Fäule zones, adjacent Cu-mineralized Kupferschiefer of southwestern Poland, and drill cores from the central and northern parts of the Zechstein basin. The Kupferschiefer samples reflect differences in base metal mineralization and in burial depth (630±5067 m). The organic matter of the Kupferschiefer is characterized by Rock-Eval and GC-MS analyses. Classification of kerogen by hydrogen and oxygen indices (HI, OI), correlations of T max vs the present depth of the Kupferschiefer, soluble organic matter (SOM) yields, and relative proportions of saturated and aromatic hydrocarbons of the SOM provide evidence for an oxidative alteration of organic matter in highly mineralized Kupferschiefer samples near the Rote Fäule zones. This is confirmed by differences in the composition of the saturated and aromatic hydrocarbon fractions of the soluble organic matter: Saturated hydrocarbons from Rote Fäule samples are dominated by short-chain n-alkanes and higher abundances of pristane and phytane relative to heptadecane (n-C17) and octadecane (n-C18), respectively, compared with samples more distant to the Rote Fäule zone. Compositional changes of the aromatic hydrocarbon fractions with decreasing distance to that zone are characterized by the occurrence of polycyclic aromatic hydrocarbons and elevated ratios of phenanthrene to methylphenanthrenes that are attributed to demethylation reactions and resulted in a decrease of the methylphenanthrene index (MPI 1). Kupferschiefer samples from the barren zone of the Polish Basin do not show these alteration patterns. The observed variations in organic matter composition with burial depth are consistent with changes due to increasing thermal maturation. Maturity assessment is achieved from MPI 1 and the methyldibenzothiophene ratio (MDR). From the relationship between the maturity of organic matter in terms of vitrinite reflectance values and depth of the Kupferschiefer strata, a continuous increase in reflectance of vitrinite is obtained within the Polish Basin. The alteration pattern of organic matter related to base metal mineralization of the Kupferschiefer corresponds to changes in the isotopic composition of organic carbon and calcite. Kerogen within, or close to, Rote Fäule zone is enriched in 13 C caused by the preferential release of isotopically light organic compounds through progressive degradation of organic matter. The opposite tendency towards lower d 13 C and d 18 O values of calcite provides evidence for isotopic exchange between carbonate and the oxidizing, ore-bearing solutions and for organic matter remineralization. In contrast, organic matter and calcite from the Kupferschiefer do not show regular trends in d 13 C with increasing thermal maturation.