Ceramic clays are generally represented by sedimentary clays of marine or lacustrine origin and with minerals of the kaolinite and illite group as the major rock-forming components. The clays, also known as kaoline rocks, are raw materials for production of whiteware ceramics such as porcelain and bone china.
From the technology process point of view of, the fired products may be assigned to whiteware or stoneware. Whiteware ceramic clays, attaining almost 50% whiteness when fired at temperature of 1,300oC, are used to produce porcelite and faiance. In turn, stoneware products are characterized by very low level of water absorption and high mechanical and chemical resistance.
Whiteware ceramic clays occur only in Dolnośląskie Voivodeship. There are two types of deposits. First of them are kaolinite clays in sandstones of the Upper Cretaceous represented by Bolko II and Ocice deposits. The second are poorly coherent sandstones with cement, rich in kaolinite represented by Janina-Zachód, Janina I and Nowe Jaroszowice deposits. The usable fraction is separated from these rocks by water-washing and the obtained concentrate contains about 30% of kaolinite clay.
Ceramic clays deposits are presented on the map.
Table 1 shows the current state of exploration and development of the above discussed deposits.
In 2016 anticipated economic resources of whiteware ceramic clays amounted to 58.47 million tonnes and decreased by 0.06 million tonnes in comparison with the previous year. It was due to the exploitation from Janina I deposit and approving the new geological documentation with recalculated resources for this deposit. Janina I was the only whiteware ceramic clays deposit exploited in Poland with the output equal 196 thousand tonnes. The exploitation increased by 84 thousand tonnes (75%) in comparison with the previous year.
The figure given below shows changes in domestic resources and production of whiteware ceramic clays in Poland in the years 1989-2016.
List of deposits is presented in table 2.
Stoneware ceramic clays occur mainly in the Lower Silesian region and central parts of the country (Dolnośląskie and Świętokrzyskie Voivodeships). Single deposits are located in Łódzkie, Mazowieckie and Śląskie Voivodeships.
In 2016 anticipated economic resources of stoneware ceramic clays amounted to 76.28 million tonnes and decreased by 0.12 million tonnes – due to the exploitation and losses (-0.24 million tonnes) and resources growth from a new documented deposit - Rozwady 1 (+0.13 million tonnes).
Anticipated economic resources within exploited deposits amounted to 5.47 million tonnes (it accounts for 7.17% of total anticipated economic resources). Almost all of these resources were covered by the detailed exploration (A+B, C1 categories), only in Baranów deposit remains 3 thousand tonnes of resources explored in C2 category. Economic resources increased by 0.43 million tonnes as a result of a new deposit development plan approved for Borkowice II deposit and amounted to 4.91 million tonnes. These resources accounted for 89.76% of anticipated economic resources of exploited deposits.
Table 3 shows the current state of exploration and development of these deposits.
In 2016, production of stoneware ceramic clays came from three deposits and was equal 244 thousand tonnes (increased by 5.63% - 13 thousand tonnes). The significant growth was recorded for Borkowice II deposit (by 10 thousand tonnes) and the exploitation from Baranów deposit has increased slightly (by 6 thousand tonnes), whereas the output dropped from Zebrzydowa Zachód deposit (by 3 thousand tonnes). List of deposits is presented in table 4.
PGE Górnictwo i Energetyka Konwencjonalna SA (PGE GiEK SA) informed that the exploitation of refractory and ceramic clays from non-documented deposits (so-called exploitation points) in the KWB Turów Mining Plant amounted in 2016 to 3.50 thousand tonnes.
The figure given below shows changes in domestic resources and production of stoneware ceramic clays in Poland in the years 1989-2016.
Prepared by: Marcin Tymiński