General information and occurrence
Foundry sands (SiO2 content >96%) with a low content of alkali pollutants which are characterized by a high sintering temperature, are the basic raw material for preparing moulds and cores masses (up to 90% of these masses) used in steel castings, iron castings and castings made of metals alloys. For making the steel castings the sands have to be characterized by the sintering temperature of 1,400°C, for the iron castings – 1,350°C, and for the non-ferrous metals castings - 1,200°C. Two types of foundry sands are differentiated on the basis of the cement and carbonates content: pure quartz sands and natural binder foundry sands. The raw material coming from some of foundry sands deposits can also be used in other applications. Pure quartz sands are used as glass sands or sometimes as sands for building and road industries.
Deposits of Polish foundry sands are situated mainly in the central and southern parts of the country and usually have the form of sand sheet deposits (map). The sand deposits are of the Quaternary, Miocene, Cretaceous and even Jurassic and Triassic age. In the vicinities of Częstochowa, foundry sands of a natural binder occur in infills of the karst forms developed in the Upper Jurassic limestones, forming small natural sand deposits of varying thickness. Foundry sand deposits located in the area between Gorzów Śląski and Żarki are represented by fine- to medium-grained sands and sandstones of the Lower Jurassic age. In turn, weakly cemented sandstones or locally loose sands of the Middle Jurassic age form foundry sand deposits found in the vicinities of Szydłowiec, Wąchock, Skarżysko-Kamienna and Jagodna as well as Opoczno and Iłża. The Cretaceous sands are known mainly from the Tomaszów Basin (where they co-occur with glass sands) as well as from the Bolesławiec Basin and the vicinities of Krzeszówek in the Lower Silesian region. The Miocene foundry sands represented by deposits of a land environments origin occur in the Konin area, at the margin of the Holy Cross Mts. and in Pomerania, and those of a marine origin occur in the Lublin Upland. In northern Poland mainly the Quaternary age sands occur – these are sediments of dune fields or fluvioglacial terrace accumulations.
Resources and output
Anticipated economic resources of foundry sands decreased by 2.21 million tonnes in comparison with 2020 and amounted to 297.42 million tonnes in 2021. The resources drop is a result of the output (-1.22 million tonnes) and the approval of a new documentation with recalculated resources (the supplement no. 2) for the Krzeszówek deposit (Dolnośląskie Voivodeship; -1.07 million tonnes). These drops were slightly compensated by minor resources growths resulting from the ongoing exploitation. The Krzeszówek deposit resources were settled as there was a quartz sandstones and feldspar-quartz sand deposit Krzeszówek I documented within the area of the Krzeszówek deposit. The raw material from the Krzeszówek I deposit can be used for the production of glass sands and foundry sands. Anticipated economic resources of exploited deposits are covered by the detailed exploration (categories A, B and C1) and are equal 46.25 million tonnes accounting for 15.55% of the total anticipated economic resources.
Table 1 shows resources and the state of development and exploration of foundry sands in Poland.
The economic resources of foundry sands decreased by 1.18 million tonnes (it means by 5.82%) in comparison with 2020 due to the exploitation and amounted to 19.08 million tonnes.
The output of foundry sands in Poland was equal 1,219.89 thousand tonnes in 2021 and increased by 245.13 thousand tonnes (25.15%) in comparison with the previous year. The exploitation volume growth was the result of increasing output from the Grudzeń-Las deposit – by 249.85 thousand tonnes (about 50%). The output remained at the similar level for the Szczakowa and Zawisna II deposits, whereas the exploitation from the Ludwików Pole B-1 deposit was on hold. For the third consecutive year, the exploitation from the Ludwików – Pole B deposit was not carried out, moreover, the exploitation of Krzeszówek deposit – in spite of a valid exploitation concession – has not started.
The figure given below shows changes in domestic resources and production of foundry sands in Poland in the years 1989-2021.
The prognostic resources of foundry sands are assessed of being equal 289.56 million tonnes as of 31.12.2018, including 37.44 million tonnes within the area of Opolskie Voivodeship and 252.12 million tonnes within the area of Śląskie Voivodeship*.
Prepared by: Agnieszka Malon
* Galos K., Lewicka E., 2020 - "Piaski formierskie (foundry sands), piaski dla odlewnictwa (moulding sands)". In: "Bilans perspektywicznych zasobów kopalin Polski wg stanu na 31.12.2018 r." (eds. Szamałek K., Szuflicki M., Mizerski W.): 321-324. PIG-PIB, Warszawa [in Polish].