Study of water and heat flow in unsaturated porous materials: mine tailings exposed to weather conditions
- Autores: Alejandro Blanco Romero
- Directores de la Tesis: Antonio Lloret Morancho (dir. tes.), Sebastià Olivella Pastallé (codir. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2009
- Idioma: español
- Tribunal Calificador de la Tesis: Lucila Candela Lledó (presid.), Enrique Edgar Romero Morales (secret.), Juan Vicente Giráldez Cervera (voc.), Vicente Navarro Gamir (voc.), Ignacio Morell Evangelista (voc.)
- Materias:
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- Resumen
A classic problem of the mine contamination is the leaching of metals and acidity to groundwater and surface water.
Primary factors influencing the amount and quality of acidic water are the relative amount of water and oxygen in the environment. In order for pyrite to oxidize, both oxygen and water must be present. A large number of abandoned high-sulfide tailings impoundments have undergone oxidation for more than 28 years at the Iberian Pyritic Belt (IPB) in the SW of the Iberian Peninsula. One of these dumps is related to the old mine Monte Romero, built by Asturiana de Zinc S. L. in 1967 to mine lead and zinc.
An autonomous station (La Mora station) monitored in the waste (pyritic loams) and to the atmosphere the physical variables needed to calculate surface energy balances and water mass balances in the tailings. Liquid pressures measured deeper in the tailings represented generally upflows except for some short episodes of rainfall. In addition, the profiles of water pressure could also be reflecting some horizontal fluxes during the infiltration episodes.
The retention curves obtained in this study displayed a dual porosity structure, which was atributed to the broad, often multimodal, void distribution functions from MIP tests.
The coupled water and heat flow in the upper 110cm of tailings was modelled by using 7 months of La Mora record (January 28th to August 31st ) from 2004.
Considering the best fittings to the measurements, the total percolation at the area under study would represent the 98% of the total rainfall; corresponding the 86% to the minimum fraction drained by local hypodermic fluxes. A 64% of the total percolation would be retained by the tailings. Deeper, an amount of liquid equivalent to the 34% of the total rainfall would flow down into a depth of 110 cm.
