Foundry sands
Foundry sands are the basic raw material for making moulds and cores used in a metal casting. The sands have to be characterized by high sintering temperatures as the temperature required for making cast steel is 1,400°C, for cast iron – 1,350°C, and for non-ferrous casting alloys - 1,200°C. Two types of foundry sands are differentiated on the basis of the cement and carbonates content: pure quartz sands and natural 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 sands for building and road industries.
Deposits of foundry sands are situated mainly in the central and southern parts of Poland and usually have the form of sand sheet deposits (map). The sand deposits range in age from the Quaternary and Miocene to Cretaceous and even Jurassic and Triassic. In the vicinities of Częstochowa, natural foundry sand deposits of a varying thickness represent infills of karst forms developed in Upper Jurassic limestones. Foundry sand deposits from 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. Cretaceous deposits of foundry sands are known mainly from the Tomaszów Basin (where they co-occur with those of glass sands) as well as from the Bolesławiec Basin and the vicinities of Krzeszówek in the Lower Silesian region. Foundry sand deposits formed of Tertiary sands deposited in land environments occur in the Konin area, at the margin of the Holy Cross Mts. and in Pomerania, and those formed of Tertiary sands of marine origin – in the Lublin Upland. Foundry sand deposits of the Quaternary age occur in northern Poland and are formed of sands of dune fields or fluvioglacial terrace accumulations.
Anticipated economic resources of foundry sands decreased due to the output and losses by 2.67 million tonnes and amounted to 302.97 million tonnes in 2017. The resources drop in non-exploited Zawisna II deposit was the result of the approval of a new documentation with recalculated resources, prepared due to the exploitation ending.
Anticipated economic resources of exploited deposits are covered by the detailed exploration (categories A, B and C1) and are equal 49.21 million tonnes accounting for 16.2% of total anticipated economic resources.
Table 1 shows resources and the state of development and exploration of foundry sands in Poland.
Economic resources of foundry sands decreased by 2.67 million tonnes in comparison with 2016 due to the termination of the exploitation concession for Zawisna II deposit (-1.56 million tonnes), the output (-1.08 million tonnes) and losses. The output of foundry sands in 2017 amounted to 1,023 thousand tonnes and decreased by almost 60 thousand tonnes (5%) in comparison with the previous year. The output declined from Grudzeń-Las (by 56.05 thousand tonnes) and Ludwików Pole B-1 (by 6.18 thousand tonnes) deposits and the exploitation from Ludwików – Pole B deposit was stopped. The exploitation from Szczakowa deposit increased by 8.97 thousand tonnes.
The figure given below shows changes in domestic resources and production of foundry sands in Poland in the years 1989-2017.
Prepared by: Agnieszka Malon
Table 1. Foundry sands - million tonnes