Deposits and mining potential of Bentonite in Croatia/Lezista I mogucnosti eksploatacije bentonita u hrvatskoj

• Published in: Rudarsko-geološko-naftni zbornik 2012-01, Vol.24 (1), p.35-35
• Main Authors: Klanfar, Mario, Jankovic, Branimir
• Format: Article
• Language: English
• Subjects: Aluminum silicates; Backfilling; Bentonite; Clay; Croatia; Deposition; Exploitation; Mining; Physical properties; Reserves; Rock
• ISSN: 0353-4529; 1849-0409

Bentonite is one of the materials that is planed to be used for buffering and backfilling in spent nuclear fuel repositories, within deep crystalline rock. There are several locations in Croatia that bentonite deposits and occurrences are found on. Some were exploited in past, and others were more or less explored. This paper presents overview of bentonite deposits, basic properties and potential resources, and mining practices in Croatia. Largest exploited deposits are found in area of Poljanska luka, Gornja Jelenska and Bednja. Surface and underground methods (driftand fill, sublevel caving) were used during exploitation. In the area of Svilaja and Lika are found potentially valuable deposits that were never exploited. Montmorilonite content ranges form 20-50% to 57-89%. Most deposits contain bentonite beds with thickness 0,4-1,6 m, and have plunge 10 degree -30 degree . Few exceptions are nearly horizontal and thick more than 5 m and even 12 m. One is declined at 70 degree and up to 40m thick. Proven reserves are about 2,3 Mt with some level of uncertainty. Average production per mine during exploitation period can be assumed to be several thousands t/y.