Spatial behavior of acid mine drainage in a peculiar stream : physical-chemical evolution from the source until the temporarlly receptor in the Iberian Pyrite Belt

Publicado em "Proceedings of the Energy and Environment Knowledge Week 2014 (E2KW2014), ISBN 978-84-697-1162-0"The Iberian Pyrite Belt is a vast concentration of massive sulphide, located in the SW of the Iberian Peninsula. Historically, this area has undergone an intense mining activity, which has left a huge amount of mining facilities and unrestored waste dumps. Mineral-water interaction in the waste dumps is responsible for the generation of acid mine drainage (AMD), causing a strong impact in the water systems. The AMD occurs when the sulfide minerals are in the presence of atmospheric oxygen and humidity, suffering oxidation reactions. As a consequence, metals and acidity are mobilized into the receiving watercourses. Such conditions have created a unique scenario in the world by the extreme degradation that characterizes the network of channels and streams in the IPB. In this context, widely described in the scientific literature, the present study aims to monitoring a singular channel affected by AMD (Campanario stream), from its origin (in the waste dump) to its confluence with an unpolluted stream. Such monitoring procedure will allow characterizing the physicochemical evolution and the mineral-water processes that regulate it

Four abandoned mines, one acid mine drainage affected river and an unsolved issue for a water supply reservoir

Publicado em "Proceedings of the Energy and Environment Knowledge Week 2014(E2KW2014)". ISBN 978-84-697-1162-

Distribution and role of benthic diatoms as acid mine drainage indicators in affected water dams

Publicado em "Proceedings of the Energy and Environment Knowledge Week 2014(E2KW2014)". ISBN 978-84-697-1162-

Methodological proposal for characterization of a mining reservoir using geophysical techniques and subsequent contrast of results by ICP and DRX

El presente estudio se llevó a cabo en la presa de agua Marismillas, en la Faja Pirítica Ibérica (FPI), SO de España. Este embalse recibe agua del río Tinto, conocido por sus altos niveles históricos de contaminación por AMD. En consecuencia, hoy en día, Marismillas se encuentra colmatado por la acumulación de materia rica en sulfuros procedentes de las de las minas de Riotinto. Una campaña de muestreo integrada se llevó a cabo con los siguientes objetivos: i) caracterizar las aguas de entrada al embalse; ii) revelar horizontes de acumulación preferencial de metales, y iii) proponer un modelo del proceso de colmatación. Las muestras se recogieron mediante tres sondeos de perforación, desde la superficie hasta la parte inferior. El objetivo del presente trabajo es la determinación horizontes de acumulación de potenciales elementos de interés económico en la Presa de Marismillas, y el establecimiento de modelos de colmatación de presas mediante técnicas geofísica y su contraste posterior con sondeos mecánicos y recuperación de testigos para su análisis químico y mineralógico mediante técnicas de ICP y difracción de R-X. En definitiva, se pretende determinar la posible existencia de un patrón detectable en la distribución de las cargas metálicas que permita optimizar la exploración y prospección posterior.The present study was performed in the Marismillas water dam, in the Iberian Pyrite Belt, SW Spain. This reservoir receives water from the Tinto River, known by its historical high levels of contamination by AMD. Additionally to soluble pollutants, sulfates and metals in the form of particulate matter have been transported for decades. Consequently, today, Marismillas is clogged by the accumulation of sulfide-rich material from the RioTinto mines. An integrated sampling campaign was accomplished with the following objectives: i) to characterize the input waters; ii) to reveal horizons for preferential accumulation of metals, and iii) to propose a model of the clogging process. The aim of this study is to determine the horizons of accumulation of potential elements of economic interest in the dam Marismillas, and the modeling of silting of dams using geophysical techniques and subsequent contrast to mechanical drilling and recovery of witnesses for chemical and mineralogical analysis by ICP techniques and X-ray diffraction. Definitively, it is to determine the possible existence of a detectable pattern in the distribution of metal loads to optimize the exploration and subsequent prospecting.info:eu-repo/semantics/publishedVersio

Hydrogeochemical variables regionalization : applying cluster analysis for a seasonal evolution model from an estuarine system affected by AMD

During the last two decades spatial and temporal metal and nutrient variations have been extensively studied in estuarine waters (e.g. Apte et al., 1990; Zwolsman et al., 1997; Grande et al., 2000,2003a; Borrego et al., 2002; Sáinz et al., 2004, 2005). This study describes the spatial evolution of the hydrogeochemical parameters, which characterise a strongly affected estuary by Acid Mine Drainage (AMD). The studied estuarine system receives AMD from the Iberian Pyrite Belt (SW Spain) and, simultaneously, is affected by the presence of an industrial chemical complex. The estuary of the Tinto and Odiel rivers is located in the southwestern part of the Iberian Peninsula (Fig. 1) and is part of a group of estuarine systems developed in the northwestern coast of the Gulf of Cádiz, in the confluence of the Atlantic Ocean and the Mediterranean Sea. The Odiel River meets the Tinto River in its mouth, originating an estuarine system known as the Firth of Huelva; both rivers share the main access channel to the Firth of Huelva, called the Padre Santo Channel (Fig. 1). The serious contamination by AMD suffered by Tinto and Odiel rivers is due to the fact that the Iberian Pyrite Belt crosses their drainage basins (Fig. 1). This 230-km-long and an average of 50-km-wide geological formation is one of the biggest sulphide deposits in the world (Leistel et al., 1998). Its metallogenic richness has been the cause of its exploitation for over 5000 years (Davis et al., 2000). As a result of such a large mining activity, more than 100 abandoned mines and over more than 200 106 m3 of waste distributed in 70 mine dumps and 14 deposits have remained in the Tinto and Odiel drainage basins (Sáinz et al., 2004). Runoff from these sources is an everlasting polluting machinery carrying sulphates and heavy metals into these two rivers (Sáinz et al., 2004), and consequently to the estuary. Together with the sulphurs exploitation in the upper part of Tinto and Odiel river basins, an important industrial complex has also been developed along the estuary banks. Fertilizer and paper industries, as well as copper foundries, were here established since 1966. The industrial activity causes an important amount of polluting disposal into the estuary waters, adding relevant amounts of heavy metals and nutrients to the sediments and to the water (Grande et al., 2000). Therefore this system is one of the most polluted in Western Europe (Ruiz et al., 1998; Elbaz-Poulichet and Dupuy, 1999; Borrego et al., 2002). Grande et al. (2003b) proposed a hydrogeochemical zonation model for this estuary based on a single sampling campaign. On the other hand, the present study defines the estuary’s behavior along an entire hydrological year, based on the proximity Pearson ratios between variables by treating the given database with statistical tools, namely cluster analysis. This treatment allows to define and to understand the spatial evolution of each one of the defined areas by observing the mixing zone displacement

Definition of a clean energy system for decontamination of acid mine waters and recovering their metal load

Acid mine drainage (AMD) is one of the largest hydrochemical problem resulting from anthropic activity, with consequences worldwide. For this reason is understandable the importance of innovative measures for recovering rivers affected AMD. Taken in account the substantial changes in terms of European legislation on water quality, under the framework of Directive 2000/60/EC (Water Framework Directive, WFD), the proposal of remediation measures for streams affected by AMD in the period marked by the standard has become even more relevant. The most common techniques, applying corrective measures to mitigate the process, have high costs of installation and maintenance, or poor performance. On the other hand, the cheaper approaches often cause undesirable discharges of pollutants. The aim of the system presented in this study is to neutralise acid mine waters and recover their metal load, using energy obtained from renewable sources. With this approach, the treated water is produced without releasing emissions into the atmosphere, without using fossil fuels and at an acceptable cost. At the same time, it allows the Cu dissolved in the waters to be separated from the rest of the metal load and sulphates. Therefore, it makes possible the metal´s recovery, transforming an environmental passive into an industrial income, in an economic context in which the price of Cu reaches around 7300 US$/ton

Properties of the ochre-precipitates formed during passive treatment of AMD for potential reuse

This work presents the properties of the waste sludge formed by neutralization in a passive system, constructed to treat AMD from an abandoned Au-mine (Jales plant, Portugal). These wastes, here designated as ochre-precipitates, pose some management problems since they are quantitatively important and interfere with the biological treatment, affecting the global performance of the treatment plant. The geochemical mineralogical and colorimetric properties of the ochre-precipitates were evaluated for environmental and management purposes. Results indicate that colour parameters as well as the iron content are in the range of synthetic pigments, suggesting a possible reuse of these materials as industrial pigments.Fundação para a Ciência e a Tecnologia (FCT