Diatomaceous rock
Diatomites are compact sedimentary rocks built mainly of diatom skeletons composed of the amorphous silica – opal. A closely related to them mineral raw material is siliceous earth, a loose rock. Diatomites and siliceous earth are widely used as filtration aids, absorbents for liquids, carriers for herbicides, fungicides and catalysts, thermal insulation and polishing materials. They are also used as thermal insulators and a mild abrasive. Up to the present, no typical diatomites with the SiO2 content over 80% have been found in Poland. Therefore, in spite of differences in the origin and the mineralogical composition, siliceous earth is treated as a substitute of diatomites and siliceous earth. The Siliceous earth is discussed in a separate section of this report.
In the Leszczawka area (Carpathian Mts.) diatomite rocks with the SiO2 content equal 72% at the average occur in the Menillite Series of the Krosno Beds. Products obtained from this mineral raw material are of a fairly limited usability. Their major uses comprise the production of light building aggregates and carriers for herbicides and fungicides. It should be noted that technological tests showed that an appropriate processing (grinding and calcination) may improve a quality of this raw material to that of proper diatomites.
Anticipated economic resources of diatomite rocks are equal slightly above 10 million tonnes. Since 2000 there has been only one deposit – Jawornik – exploited. The extraction of diatomite remains at the small scale and amounted in 2018 to 0.58 thousand tonnes (Table 2).
The table below shows reserves and the state of development and exploration of diatomite rocks in Poland.
Except of the already documented deposits, there are possibilities of markedly increase the hitherto known resources of this raw material. Perspective resources of the diatomaceous rock in the Leszczawka area are estimated at about 10 million tonnes. The chances for a discovery of new large diatomite deposits seem to be much higher in the case of the Menillite Series of the Krosno Beds in the areas of Godowa, Błażowa - Piątkowa - Harta - Bachórz and Dydynia - Krzywe (Podkarpackie Voivodeship).
Prepared by: Robert Bońda
Table 1. Diatomaceous rock - million tonnes