Dumps of waste and sterile matter from mine activities are potential sources of environmental contamination with their contents of heavy metals and arsenic, especially when these materials contain sulfide minerals and high metal levels. The objective of this study was the characterization of refuse from a gold mine area in the State of Minas Gerais, Brazil, in order to evaluate acid drainage and metal solubilization problems, and local revegetation planning. Surface samples (0-20 cm) were collected and submitted to routine […]

This work was carried out to study methods of sulfide analysis to obtain a fast, accurate and reproducible procedure to evaluate acid drainage in samples of rocks and sediments.The samples were submitted to oxidative digestions with H2O2 and nitric-hydrochloric acid solutions (3:1, v/v).The S in the extracts was determined by gravimetry, atomic absorption spectrophotometry (AAS) for remaining Ba, turbidimetry and colorimetry.The Fe and Pb contents in the extracts were determined by AAS.Acidity was also determined by titration with NaOH in […]

Acid drainage, resulting from sulfide oxidation, is an environmental problem which may impair soil and water sources quality. Such impact may occur in several environments, but it is commonly related to coal mining. This work was carried out to study the kinetics of pyrite oxidation in coal mining spoil from Candiota (RS) Brazil, under different conditions of atmospheric O2 access and pH. The study aimed to evaluate the possibility of adjusting carbonate dissolution rate to the sulfide oxidation rate in […]