Geochemistry: Exploration, Environment, Analysis; August 2003; v. 3; no. 3;
p. 229-237; DOI: 10.1144/1467-7873/03-003
© 2003 Geological Society of London
Arsenic mobilization from waste piles of the El Terronal mine,Asturias, Spain
J. Loredo,
A. Ordóñez,
C. Baldo and
J. García-Iglesias
Departamento
de Explotación y Prospección de Minas. Universidad de
Oviedo, Escuela Técnica Superior de Ingenieros de Minas, c/
Independencia, 13. 33004 Oviedo, Asturias,
Spain (e-mail:
jloredo@correo.uniovi.es)
Arsenic
is associated with Hg in the mercury deposits of the Asturias region of
northern Spain. Until 1974, the mines of La Peña and El Terronal
exploited an ore deposit located in the valley of the San Tirso River
(Mieres district). At this site, a great volume of waste material from
mining and metallurgical works have been stock-piled for years,
constituting a spoil heap of about
20 000 m2 in area. Total As
concentrations in representative samples of waste materials on the
surface of the spoil heap reach a maximum value of
72 153 mg kg1 and an
average value of 15 967 mg
kg1; analysis of deeper samples
(trenches on the spoil heap) exceed 99 999 mg
kg1. The total flow of polluted water
from its circulation through the spoil heap is estimated at
3465 m3
a1. Weathering processes facilitate
the dissolution and leaching of As and heavy metals in the ore and
waste material. Arsenic contents in surface waters (San Tirso River)
immediately downstream of the spoil heap reach 7.9 mg
l1. The impact on the area, reflected
by elevated concentrations of As in adjacent soils, biota and
surface/underground waters, is
discussed.
KEYWORDS: Arsenic, mercury
mining, spoil
heaps, Asturias
Copyright © 2009 by Geological Society of London