Economic assessment of the Northern Copper Belt deposits – a future resource base of copper and silver ores in SW Poland

Abstract

Seven undeveloped sediment-hosted stratiform Cu-Ag deposits constitute a future resource base of copper and silver ores in the Fore-Sudetic Monocline in SW Poland. Among these, four have only recently been discovered and documented: Nowa Sól, Sulmierzyce North, Mozów (forming a part of the Northern Copper Belt) and Żary. The three remaining deposits – Bytom Odrzański, Głogów and Retków – surround the currently mined New Copper District to the north-west, north and north-east. Polish Cu-Ag deposits are polymetallic: copper, silver, lead, nickel as well as subordinate rhenium and gold are currently extracted. However, they show high reporting of other by-product metals, such as cobalt, molybdenum, vanadium, zinc and rare earth elements. Unit ore values expressed in US dollars per metric ton of ore have been calculated for deposits in the Northern Copper Belt to compare them with other undeveloped and mined Polish sediment-hosted stratiform Cu-Ag deposits. The calculated unit ore values for the deposits studied are primarily influenced by copper, with a significant contribution (up to 29%) from silver. In terms of base metals other than copper, their contribution to the unit ore values is here relatively low, accounting for only 1–11% of the total value. The proportions of silver and lead in the unit ore value show a trend: they tend to be lower in the vicinity of oxidized fields and gradually increase with distance from these oxidized areas. The share of nickel in the unit ore value, on the other hand, is not influenced by distance from the oxidized fields. Instead, it is dependent on factors such as the thickness and organic content of the shale ore, which affect the accumulation of non-ferrous, redox-sensitive by-product metals, including nickel. Furthermore, we provide a comparative analysis of the total unit ore value among Polish sediment-hosted stratiform Cu-Ag deposits. Particular emphasis is placed on the deposits that constitute the future resource base of copper and silver ores in southwest Poland. A market perspective is drawn to highlight the influence of metal price fluctuations on the unit ore values of the various deposits. By examining the dynamic nature of metal prices, the study offers insights into how changes in market conditions can impact the economic viability of deposits located in different parts of the Fore-Sudetic Monocline. The deposits that constitute the future resource base of copper and silver in Poland show remarkably high copper and silver grades, resulting in significantly higher unit ore values compared to other world-class deposits of different types such as porphyry, epithermal, and IOCG (iron oxide copper gold) deposits.