Siliceous earth occurs as a result of Upper-Cretaceous and Early-Tertiary opokas and gaizes weathering. It is built mainly from opal. Siliceous earth resembles diatomites in physical features. It is used in a chemical industry as a carrier for catalysts, mineral fertilizers, herbicides, pesticides and fungicides in agriculture as well as a raw material for refination and filtration and constituent of synthetic moulding mass.
Deposits of siliceous earth occur mainly in tectonic troughs at the margin of the Holy Cross Mts. (Piotrowice and Dąbrówka deposits) and in the Lublin Upland (Lechówka deposit), in the form of sedimentary covers overlain by Oligocene rocks.
Table 1 shows resources and the current state of exploration and development of siliceous earth deposits in Poland.
Anticipated economic resources amounted to 2,223 thousand tonnes in 2016. Nowadays there is concession for exploitation issued only for Lechówka II deposit. The output from this deposit has been carried out temporarily, since 2014 the raw material has not been exploited.
Prepared by: Robert Bońda