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 as well as a constituent of a synthetic foundry mass.
Deposits of siliceous earth 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.
Anticipated economic resources of the siliceous earth amount to 2,223 thousand tonnes. Until recently, the exploitation has been temporarily carried out only from Lechówka II deposit. Since 2014 the raw material has not been exploited, therefore the resources have not changed in 2018.
Prepared by: Robert Bońda