Seasonal fluctuations and geochemical modeling of acid mine drainage in the semi-arid Puna region: The Pan de Azúcar Pb–Ag–Zn mine, Argentina

Geochemical modeling of precipitation reactions in the complex matrix of acid mine drainage is fundamental to understanding natural attenuation, lime treatment, and treatment procedures that separate constituents for potential reuse or recycling. The three main dissolved constituents in acid mine drainage are iron, aluminum, and sulfate. During the neutralization of acid mine drainage (AMD) by mixing with clean tributaries or by titration with a base such as sodium hydroxide or slaked lime, Ca(OH)2, iron precipitates at pH values of 2–3 if oxidized and aluminum precipitates at pH values of 4–5 and both processes buffer the pH during precipitation. Mixing processes were simulated using the ion-association model in the PHREEQC code. The results are sensitive to the solubility product constant (Ksp) used for the precipitating phases. A field example with data on discharge and water composition of AMD before and after mixing along with massive precipitation of an aluminum phase is simulated and shows that there is an optimal Ksp to give the best fit to the measured data. Best fit is defined when the predicted water composition after mixing and precipitation matches most closely the measured water chemistry. Slight adjustment to the proportion of stream discharges does not give a better fit.

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Precipitation of heavy metals from acid mine drainage and their geochemical modeling

Selected Scientific Papers - Journal of Civil Engineering ◽

10.2478/sspjce-2014-0009 ◽

2014 ◽

Vol 9 (1) ◽

pp. 79-86 ◽

Cited By ~ 1

Author(s):

Aneta Petrilakova ◽

Magdalena Balintova ◽

Marian Holub

Keyword(s):

Acid Mine Drainage ◽

Mine Drainage ◽

Geochemical Modeling ◽

Vital Role ◽

Dissolved Metals ◽

Environmental Preservation ◽

Surface Water Hydrology ◽

Acid Mine ◽

Modeling Software ◽

High Concentrations

Abstract Geochemical modeling plays an increasingly vital role in a number of areas of geoscience, ranging from groundwater and surface water hydrology to environmental preservation and remediation. Geochemical modeling is also used to model the interaction processes at the water - sediment interface in acid mine drainage (AMD). AMD contains high concentrations of sulfate and dissolved metals and it is a serious environmental problem in eastern Slovakia. The paper is focused on comparing the results of laboratory precipitation of metal ions from AMD (the Smolnik creek, Slovakia) with the results obtained by geochemical modeling software Visual Minteq 3.0.

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Acid mine drainage in semi-arid regions: the extent of the problem in the waters of reservoirs in the Iberian Pyrite Belt (SW Spain)

Hydrology Research ◽

10.2166/nh.2013.086 ◽

2013 ◽

Vol 46 (1) ◽

pp. 156-167 ◽

Cited By ~ 12

Author(s):

M. Santisteban ◽

J. A. Grande ◽

M. L. de la Torre ◽

T. Valente ◽

J. C. Cerón

Keyword(s):

Acid Mine Drainage ◽

Mine Drainage ◽

Chemical Characterization ◽

Iberian Pyrite Belt ◽

Climatic Conditions ◽

Sw Spain ◽

Acid Mine ◽

General Functioning ◽

High Concentrations ◽

Semi Arid

There are many reservoirs in the Iberian Pyrite Belt (IPB), SW Spain, which receive contributions from watercourses affected by acid mine drainage processes, characterised by low pH values and high concentrations of heavy metals and sulphates. When they reach the reservoirs, the waters increase its pH, which will cause most of the metal load carried by the mining channel to precipitate into the reservoir itself and accumulate on its floor. The silting of reservoirs is an environmental problem which can affect the loss of storage capacity, their general functioning and aquatic ecosystems. A study of these is vital to allow both preventative and corrective measures to be established. Climatic conditions are the most significant external controlling factors in terms of the degree and type of mining pollution. The study area presents characteristics typical of the semi-arid Mediterranean climate, with annual precipitation of around 630 mm/year; moderate temperatures with average annual values of 17.1 °C and a temperature range of 50 °C. The aim of this study is to carry out a physical–chemical characterization of the waters where they enter the reservoirs located in the IPB over the course of a hydrological year and to establish possible interdependencies between the various parameters.

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