Pokładowe wystąpienia soli potasowo-magnezowych w południowo-zachodniej Polsce – potencjał złożowy

Abstract

Stratiform potash deposits in south-western Poland – resource potential.A b s t r a c t. New borehole data (from boreholes drilled after 2014) and reinterpretation of historical well logs enabled to update the acreage and reserve potential of Upper Permian (Zechstein) stratiform potash-bearing deposits in SW Poland (Fore-Sudetic area). These deposits, referred to as the Older Potash (K2) and the Younger Potash (K3), are included in the Stassfurt (Z2) and Leine (Z3) cyclothems. Within the present day extent of both units, several prospective areas with the maximum depth to the potash seam of 2 km and its thickness over 2 m have been contoured. For each such area, predicted reserves of potash rock have been calculated (using such parameters as the area, average potash seam thickness, and specific weight of potash rock assumed at 2.1 Mg/m3). 7 prospective areas (defined by 98 wells) of the Older Potash (K2) deposits have the reserves estimated at 3.2 bln Mg and a total surface area of 454 km2. 6 areas (contoured by 23 wells) of the Younger Potash (K3) deposits characterize rocks of predicted reserves of 288.8 mln Mg and a total surface area over 60 km2. Therefore, the area of SW Poland offers a relatively high resource potential for potash salts and a more detailed geological insight (and possible future exploitation) of 13 prospective areas with total predicted reserves of 3.53 bln Mg and a total surface area of up to 514 km2. Preliminary calculation of possible amounts of K2O in these reserves (assuming a low average K2O content at 1%) suggests 35.32 mln Mg of potassium oxide. Because the potash-bearing seams in the study area are composed mainly of chloride K-Mg minerals such as sylvine (KCl) and carnallite (KClMg · Cl2 · 6H2O) easily dissolved in water, these seams are favourable for relatively cheap exploitation by underground leaching.