During 30-40 years of the tailing existence large amounts of heavy metals were leached from the sludge and accumulated in the clay bottom. Low permeability of the clayey bottom below the sludge deposit indicates that vertical contaminant transport will take place as result of diffusion. Diffusion as physical process is described by Fickian empirical relation that can be used for prediction of the contaminant transport development at time. The paper presents model solution applied with an example of the vertical transport of two heavy metals - lead and zinc - in natural clay base of Lintich sludge deposit. Results confirm that diffusion is very slow process from time-scale aspect, but diffusive flux of heavy metals after reaching steady state is quite large. and Počas 30-40 ročnej existencie odkaliska Banská Štiavnica - Lintich sa z ''kalu'' vylúhovali veľké množstvá ťažkých kovov a následne sa akumulovali v ílovom podloží. Nízka priepustnosť ílového podložia pod odkaliskom indikuje, že dominantným transportným mechanizmom bude difúzia. Difúziu ako fyzikálny proces možno opísať pomocou Fickovho empirického vzťahu, ktorý sa dá použiť na posúdenie vývoja migrácie kontaminantov v čase. V príspevku bolo modelované riešenie použité na príklade vertikálneho transportu dvojice ťažkých kovov - olova a zinku - v prirodzenom ílovom podloží odkaliska Lintich. Výsledky potvrdzujú, že z časového hľadiska je difúzia pomalý proces, avšak difúzny tok ťažkých kovov po dosiahnutí času ''prieniku'' ílovej bariery je značne veľký.
Reduced soil tillage practices are claimed to improve soil health, fertility and productivity through improved soil structure and higher soil organic matter contents. This study compares soil structure stability of soil aggregates under three different tillage practices: conventional, reduced and no tillage. The erosive strength of soil aggregates has been determined using the abrasion technique with the soil aggregate erosion chambers (SAE). During abrasion soil aggregates have been separated into the exterior, transitional and interior regions. The forces needed to remove the material from the aggregate were calculated as erosive strength and compared with the tensile strength of the aggregates derived from crushing tests. The relationship between aggregate strength and other soil properties such as organic carbon and hydrophobic groups’ content has also been identified. The results show that erosive and tensile strength of soil aggregates is very low in topsoil under conventional and reduced tillage comparing with the subsoil horizons. Negative correlation was found between the content of organic carbon, hydrophobic compounds and erosive aggregate strength which suggests that the stabilising effect of soils organic carbon may be lost with drying. The positive relationship between the tensile strength and erosive strength for aggregates of 8–5 mm size suggests that the total strength of these aggregates is controlled by the sum of strength of all concentric layers.