Alicja Pietrzela

The discovery of the Northern Copper Belt in SW Poland is a result of an extensive exploration project with a key role played by various science-related methods. The project relied on mapping the distribution of mineral zones in the entire Fore-Sudetic Monocline, a unit known for its occurrences of Cu-Ag orebodies. This approach involved the examination of historical drill cores from over 400 oil and gas holes in this area, with the collection of samples for laboratory analyses. A close relationship was confirmed between the distribution of orebodies and the transformation of organic matter. Rock-Eval pyrolysis was also performed on selected samples. The tests of rock specimens were accompanied by the reprocessing of historical gravimetric and seismic surveying results. Field magnetotelluric surveying was also performed in certain areas. This phase resulted in the identification of areas with a high probability of finding the best ore, allowing for the initiation of the drilling stage. So far, 37 exploratory boreholes have been drilled in those locations, nearly all of them with highly positive results. The Northern Copper Belt consists of three deposits, Nowa Sól, Mozów, and Sulmierzyce North, along with numerous prognostic areas distributed therebetween. The future production of copper, silver, and the accompanying valuable elements presents a chance to provide the whole of Europe with a new plentiful supply of those critical raw materials.

Mineralogy and geochemistry of the Kupferschiefer in the Nowa Sól, Mozów and Sulmierzyce North Cu-Ag deposits, Northern Copper Belt, SW Poland

The Nowa Sól deposit is a part of the newly discovered Northern Copper Belt and is situated some 30 km NW of the Lubin–Sieroszowice mining district (the so-called New Copper District) in SW Poland. The ore horizon spans across the upper part of the Lower Permian (Rotliegend) terrestrial redbeds and the lower part of the Upper Permian (Zechstein) marine rocks. It comprises three lithotypes: sandstone, shale and carbonate. The high-grade shale ore has polymetallic characteristics and is a crucial host for by-product metals such as Ag, Co and Ni (studied in this paper), but also Mo, V and Re. The results of bulk-rock and electron microprobe as well as mineralogical (optical and scanning electron microscope) data of the mineralized, organic-rich shale ore from the Nowa Sól deposit are presented. This thin stratigraphic horizon, ranging from 0.06 to 0.59 m, shows notable concentrations of critical metals, including on average 15.9 wt% Cu, 715 grams per tonne (g t ^-1 ) Ag, 318 g t ^-1 Co and 345 g t ^-1 Ni. It constitutes less than 10% of the total ore mass, but accounts for 36% of the Ag, 40% of the Ni and 42% of the Co found within the deposit. The ore sulfides in the mineralized shale in the Nowa Sól deposit include chalcocite, djurleite and bornite, accompanied by digenite, covellite, tennantite, galena, sphalerite and pyrite. The Ag content within the Cu sulfides exhibits a linear decrease: chalcocite > djurleite > bornite. Three primary Ag minerals are identified within the shale ore, namely native Ag, Ag amalgam and stromeyerite. Two types of Ag amalgam are observed: Hg-rich and Hg-poor. Cobaltite and gersdorffite represent the primary Co and Ni minerals, occurring as micrometre-sized inclusions within chalcocite and djurleite. Textural observations suggest that the Ag, Co and Ni mineralization postdates the major phase of Cu sulfide precipitation. It is shown that in the Nowa Sól deposit, the Kupferschiefer horizon has acted as a geochemical barrier for the above-mentioned metals during protracted time, from early syndepositional to late epigenetic stage of basin evolution. Supplementary material: The supplementary material contains the results of the electron microprobe analyses and the specific experimental conditions employed for these analyses – available at https://doi.org/10.6084/m9.figshare.c.6873631

Three new world-class sediment-hosted stratiform copper deposits have recently been documented in SW Poland, in the deep parts of the Fore-Sudetic Monocline: Nowa Sól, Sulmierzyce North and Mozów. Along with the adjacent prognostic areas, these deposits form an extensive west–east-trending belt, distant from the well-known deposits of the Sieroszowice–Lubin area and referred to as the Northern Copper Belt. This major discovery was a result of an exploration program performed by the Canadian Miedzi Copper Corporation, which involved studies of archival data and the company's own drilling program. Investigation of the core material included microscopic observations of thin sections and chemical analyses using inductively coupled plasma (ICP) mass spectrometry and/or ICP optical emission spectrometry. The aim of this study was to compare available geochemical data from the documented deposits and determine the distribution patterns of the main and accompanying metals. Particular attention was paid to Cu, Ag, Pb, Zn, Co, Ni, Mo, V and Au. Each of the studied deposits is characterized by a different position of the ore mineralization in the lithological profile. Average concentrations of the analysed elements and their distribution in the ore series, both vertically and laterally, indicate that distinct mineralizing systems were responsible for the formation of each orebody. Among the main factors influencing metal distribution in the analysed deposits are: the spatial range of the epigenetic, oxidized Rote Fäule facies; composition and thickness of the source rocks for the mineralizing brines; and tectonics.

The Northern Copper Belt is located in south-western Poland, a region well known for its copper and silver occurrences of varying significance. This area also includes the abandoned mines of the North-Sudetic Trough (Old Copper District), as well as the currently active New Copper District in the southern part of the Fore- Sudetic Monocline. The vast exploration programme of Miedzi Copper Corp. initiated in 2011 in the northern, deeper part of the Fore Sudetic Monocline provided new data about the deeper parts of this geological unit, located north of the known deposits. A number of prospective areas with Cu-Ag mineralization were investigated, which ultimately resulted in the discovery of three new Cu-Ag deposits. Both the prospective areas and the documented deposits form the so-called Northern Copper Belt, which as a whole has high potential for the identification of new ore deposits and an increase in resources. A description of these three new deposits is provided along with characteristics of the areas of their possible extension, and the additional prospective areas with hypothetical and speculative resources. The new deposits are compared to other Polish Cu-Ag ore deposits, with an emphasis on differences in their geological structure and mineralogy. The paper also presents a brief summary of the applied new exploration tools which have led to this discovery.

The protection of copper and silver ore resources in the Polish Lubuskie Province requires certain steps to be taken, the suggestions for which are presented in this article. It addresses both known and newly discovered ore deposits, as well as prospective areas and places of ongoing exploration, which throughout the paper are collectively recognized as potential Cu-Ag mining areas. The example of Lubuskie Province was chosen as an exceptional region with multiple known areas of copper and silver ore potential, but no active mining operations until now. The study focuses on the nature and location of all potential mining areas in Lubuskie Province, and subsequently suggests the means of their protection which can be implemented today, as well as in the future. Such means should be introduced by way of new or amended legal regulations. Certain major changes to Polish law are necessary to provide sufficient protection of both currently known, as well as possible future deposits, against such use of land which would prevent the extraction of their resources. The study shows that the legal regulations effective in Poland today are insufficient or too vague, as they do not include any provisions concerning prospective resources, as well as areas of active mineral exploration, instead focusing solely on officially registered mineral deposits. Therefore, the proposals of new solutions providing better protection of all potential Cu-Ag mining areas are presented in this article.