Las plantas de arenas y gravas (áridos aluviales) como un nuevo tipo de placer artificial de minerales pesados. El ejemplo de la gravera del Corb en el Río Segre (Balaguer, NE de la Península Ibérica)

• Autores: Manuel Viladevall Solé, A. Paris, J. Antonio Pacheco Benito, P. Vergel, Ignasi Queralt Mitjans, A. Casas Planes, X. Font Segura, J. María Carmona, Lluís Rivero Marginedas, J.L. Cadenas, Víctor Pinto Miguel
• Localización: Geotemas (Madrid), ISSN 1576-5172, Nº. 6, 1, 2004 (Ejemplar dedicado a: IV Congreso Geológico de España (Zaragoza, 12-15 julio, 2004)), págs. 237-240
• Idioma: español
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• Resumen

  • The Segre River rises in the central Pyrenees and is the main tributary of the Ebro River. The drainage area is principally made up of Hercynian metasedimentary rocks and late-Hercynian granites. Exploration carried out in the alluvial plain of the Segre River in 1989-91 shows that the terrace and the flood plain present a non-economic concentration of gold and other heavy minerals. Nevertheless, the economic recovery of these by-products may be viable during the operation of the sand and gravel plants.

    Gold and other heavy minerals are concentrated in the lowest sand fractions during primary and secondary sand and gravel sieving and washing. The two processes give rise to a factor of enrichment of 5.

    Could sand and gravel plants be regarded as artificial placer ore deposits? Carpets with riffles or gravimetric concentrators were employed in the final part of the enrichment factor at the El Corb plant near Balaguer. Two materials were obtained after these concentration processes: a black sand rich in gold, zircon, ilmenite, rutile, magnetite, monacite, scheelite, cassiterite, iron and sulphides, and a clean sand fraction without pathological materials such as sulphides, iron and radioactive minerals.