Ochreous Precipitates from Smolník Abandoned Mine

Abstract

Metal sulphides of rock origin disrupted by mining activities exposed to oxidation conditions (contact with water and atmospheric oxygen) cause start of processes producing Fe, other metals, sulphates and acidity. The result of oxidizing weathering of iron sulphi- des is the production of AMD and the consequent formation of ochreous precipitates in drainage systems and in the surroundings of AMD seepage on the surface. Apart from these facts, the genesis of AMD is facilitated by indigenous chemolithotrophic iron and sulphur oxidizing bacteria, especially of genus Acidithiobacillus and Leptospirillum. The long-term monitoring of AMD waters col- lected at the shaft Pech point at the enduring risk of contamination of particular components of environment in mining area Smol- ník. Elemental analysis, X-ray diffraction, Mössbauer spectroscopy and scanning electron microscopy of the ochreous precipitates formed in Smolník AMD stream revealed Schwertmannite as the dominant solid phase in the precipitates. The chemical analysis of AMD effluents and the elemental composition of related sediments indicated considerable scavenging potential of the ochreous precipitates towards arsenic, aluminium, lead and other metal species.