General information and occurrence
The siliceous earth occurs in the result of the Upper-Cretaceous and Early-Tertiary opokas and gaizes hypergenic weathering. It is built mainly from the opal. The siliceous earth resembles diatomites in the physical features as: - a high porosity and absorptive capacity; - a refractoriness; - an acid activity resistance; - a high SiO2 content. It is used in a chemical industry as a carrier for catalysts, mineral fertilizers, herbicides, pesticides and fungicides in the agriculture, to the needs of the refining and filtration processes of edible oils, as an insulating material, and as well as a constituent of a synthetic foundry mass.
The siliceous earth deposits occur in tectonic troughs at the margin of the Holy Cross Mts. (Piotrowice and Dąbrówka) and in the Lublin Upland (Lechówka), in the form of sedimentary covers overlain by the Oligocene rocks.
Table 1 shows resources and the current state of exploration and development of siliceous earth deposits in Poland.
The anticipated economic resources of the siliceous earth amount to 2,223 thousand tonnes. Till 2014, the exploitation of Lechówka II deposit was carried out, nowadays all of the raw material deposits are abandoned. Therefore, the resources did not change in 2020. There are not enough resources of the porous siliceous raw materials of a high quality in Poland. The scarcity of the raw material is balanced by the import. In Poland, there is only one prognostic area of the siliceous earth occurrence with the significant resources (3.13 million tonnes) – indicated in the vicinities of Janów village near Chełm*.
Prepared by: Robert Bońda
* Wołkowicz K., 2020 - Ziemia krzemionkowa (siliceous earth). In: Bilans perspektywicznych zasobów kopalin Polski wg stanu na 31.12.2018 r. (eds. Szamałek K., Szuflicki M., Mizerski W.): 359-361. PIG-PIB, Warszawa [in Polish].