Hydrochemical changes in a reservoir that receives water contaminated by acid mine drainage

The aim was to characterize hydrochemical changes that take place in the Sancho reservoir, which receives waters contaminated by acid mine drainage (AMD) from the Meca River (Iberian Pyrite Belt, SW Spain). The sampling procedure comprised bimonthly campaigns carried out between October 2011 and May 2012, in the entrance of the reservoir and in the input river waters. In addition to in situ parameters, heavy metals and sulphate were analysed in the laboratory by photometry and atomic absorption spectrometry, respectively. The database was submitted to statistic treatment through the STATGRAPHICS Centurion XVI.I software. The results show a clear relationship between the sampling site in the entrance of the reservoir and in the watercourse, with an almost instantaneous cross-correlation. At the beginning of the sampling period a small rise in pH at both sites was detected, coinciding with a reduction in the concentration of heavy metals. This attenuation results from the dilution process caused by rain as well as the sorption by iron oxyhydroxysulphates that precipitate as a consequence of the above-mentioned rise in pH. The time changes that were detected in this system are due to the influence of input waters from the waste dumps of the Tharsis mines.

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Acid mine drainage (AMD) contamination in coal mines and the need for extensive prediction and remediation: a review

Journal of Degraded and Mining Lands Management ◽

10.15243/jdmlm.2021.091.3129 ◽

2021 ◽

Vol 9 (1) ◽

pp. 3129-3136

Author(s):

Theophilus Ile Ojonimi ◽

lemona C Okeme ◽

Tina Phiri Chanda ◽

Eneojo Godwin Ameh

Keyword(s):

Heavy Metals ◽

Acid Mine Drainage ◽

Mine Drainage ◽

Environmental Regulations ◽

Atmospheric Oxygen ◽

Coal Mines ◽

Coal Waste ◽

Acid Mine ◽

Waste Dumps ◽

The Impact

Globally, the major source of environmental pollution as a result of mineral exploitation and processing is acid mine drainage (AMD). AMD refers to outflowing streams of acidic constituents from pyrite-bearing ore mines. The exposure of pyrite (FeS2) in coal waste dumps to atmospheric oxygen and water in the presence of microbial communities promotes the formation of sulphuric acid which leaches out the inherent heavy metals into the mine discharge, a phenomenon called pyrite oxidation. AMDs are usually characterized by a convoy of toxic heavy metals, most of which are transition elements (copper, nickel, zinc, etc.) and arsenic at concentrations higher than the limits permitted by environmental regulations. The impact of this acidic discharge from coal mines on downstream/underground waters and farm lands within the corresponding mining zones have been severally reported by previous researchers, but not so much have been discussed on extensive prediction and remediation. It is in view of this that the current paper reviews the need for extensive prediction and remediation approach for coal mines under the following subheadings; General introduction, AMD sources identification, representative sampling, adoption of a prediction model, determination of AMD potential and quality via static and kinetic tests and the development of an economically sustainable remediation strategy. It is thought that this article would be useful to academia as well as policy makers that are responsible for the development and implementation of environmental regulations in coal mines.

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Mechanisms and Remediation Technologies of Sulfate Removal from Acid Mine Drainage

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.610-613.3252 ◽

2012 ◽

Vol 610-613 ◽

pp. 3252-3256

Author(s):

Mei Qin Chen ◽

Feng Ji Wu

Keyword(s):

Heavy Metals ◽

Acid Mine Drainage ◽

Mine Drainage ◽

Metal Corrosion ◽

Sulfate Ion ◽

High Concentration ◽

Biological Reduction ◽

Acid Mine ◽

Sulfate Removal ◽

Co Precipitation

Acid mine drainage (AMD) has properties of extreme acidification, quantities of sulfate and elevated levels of soluble heavy metals. It was a widespread environmental problem that caused adverse effects to the qualities of ground water and surface water. In the past decades, most of investigations were focused on the heavy metals as their toxicities for human and animals. As another main constitution of AMD, sulfate ion is nontoxic, yet high concentration of sulfate ion can cause many problems such as soil acidification, metal corrosion and health problems. More attention should be paid on the sulfate ion when people focus on the AMD. In the paper, sulfate removal mechanisms include adsorption, precipitation, co-precipitation and biological reduction were analyzed and summarized. Meanwhile, the remediation technologies, especially the applications of them in China were also presented and discussed.

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