Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.754019
Title: Geochemical aspects at the Tintillo-Corta Atalaya acid mine drainage site, Iberian Pyrite Belt, southwest Spain
Author: Mathewson, Emma
ISNI:       0000 0004 7427 0820
Awarding Body: University of Brighton
Current Institution: University of Brighton
Date of Award: 2017
Availability of Full Text:
Access from EThOS:
Access from Institution:
Abstract:
Acid mine drainage (AMD) is a major environmental problem in many active and former mining regions worldwide. Prediction of the nature of effluents released from mine sites and their environmental impacts is a challenging and dynamic problem as AMD is affected, both by the textural and compositional features of sulphide ores and their weathered spoils and by water-rock interactions in receiving waters. This thesis examines AMD processes in the headwater region of the Tintillo River (a high level tributary of the Odiel River) that receives effluents draining the spoil heaps of the Corta Atalaya (CA) mine, Iberian Pyrite Belt (IPB), South-West Spain. The district and CA itself represent some of the largest massive sulphide mines in the world. The aim of the work presented here is to assess AMD generation and impacts around the CA mine focusing on, (a) AMD generation processes in the mine and its spoil heaps and (b) the impacts of site AMD on river water chemistry and river morphology. Tintillo River waters are extreme examples of AMD-affected Mg-SO4 type waters characterised by high S, Mg, Fe and Al concentrations and low pH (~2.56). Intense sulphide oxidation at all scales has resulted in the release of high concentrations of Fe and SO4 and accessory metals (e.g. Cu, Zn, Cd, As and Co) into the fluvial network with concomitant dissolution of gangue minerals and hydrolysis reactions leading to the mobilisation of Mg, Al, Si, K and Na. Future differential rates and products of weathering between the meta-rhyolites that dominate CA spoil could profoundly affect the partitioning of major and trace elements (e.g. metals co-precipitated, adsorbed and or otherwise retained by current secondary mineral accumulations), impacting the subsequent parts of the system. Two major geomorphological expressions (terrace formations and evaporite accumulations) are the result of hydrogeochemical processes following outwash of acidic effluents at the study site. Secondary minerals at the site significantly influence the geochemical fractionation of hazardous elements. Dissolution of soluble salts (characteristically Mg- varieties of magnesiocopiapite, epsomite, and hexahydrite) and neo-formed jarosites from spoil and riverine hinterlands results in an annual cycle of rapid metal and acidity transference from CA spoil and Tintillo headwaters to the downstream environment. The high affinity of jarosites for heavy metals and the capacity of watersoluble evaporites to coprecipitate, adsorb and/or scavenge a suite of toxic metals (including Co, Cu, Mn, Zn, Ni and Cd) result in geomorphological and secondary mineral interfaces that are major and dynamic conduits for metal transport within and through the system, particularly during flood events.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.754019  DOI: Not available
Share: