The production of Acid Mine Drainage (AMD), as a result of the oxidative dissolution of sulphides, and the release of hazardous elements in the environment are main pollution problems affecting natural watercourses in mining areas, with sulphide-rich residues. An important tool for geochemical assessment of abandoned mine areas are kinetic tests, as they provide an insight into the behaviour of the waste-rocks during the interaction with meteoric waters, giving also useful indications of metal mobility and chemical composition of the run-off waters. In this study two different kinetic tests were applied to assess the generation of AMD from the run-off water of the Hop waste-rock dump, at the Rosia Montana ancient mining area (Apuseni Mountains, Romania).SPLP results showed that eco-toxic elements content in filtered solutions is generally low: Cu ranges from 0 to 98 ppb (mean 14), Zn ranges from 21 to 570 ppb (mean 155) and As ranges from 1 to 7 ppb (mean 2.5). These data are in agreement with the results of bulk waste-rock material chemical composition, whose metal concentrations are in the range of tens of ppm with the exception of As, that shows a content one order of magnitude higher (Azzali et al., 2010). The pH values vary greatly from 2.9 to 8.9, according to mineralogical and geochemical composition of the waste material. The sulphate content ranges from 13.5 to 475 ppm and exceeds the European limit for drinking waters (250 ppm, EU 1998) in 6 samples. A significant positive relationship between sulphate content and EC was found.Modified column test results showed that geochemical features of the solutions tend to stabilized after 3 weeks: pH values grow from 2.5 to 2.7 (mean values) while EC values and sulphate concentration, though highly variables for the three different grain-size samples, clearly decrease.
|Titolo:||Combinationn of leaching and column test for the assessment of AMD generation from the hop waste-rock dumo (Rosia Montana, Romania)|
PORRO, SILVIA (Primo)
DE CAPITANI, LUISA (Ultimo)
|Settore Scientifico Disciplinare:||Settore GEO/08 - Geochimica e Vulcanologia|
|Data di pubblicazione:||2011|
|Appare nelle tipologie:||01 - Articolo su periodico|