Impact of mining activities on soils in a semi-arid environment: Sierra Almagrera district, SE Spain

Abstract

Field and laboratory-column studies were undertaken in order to investigate soil contamination derived from past mining activity in the Sierra Almagrera (SA) district in southeast Spain. The tailings, soil and sediment samples that were collected showed high concentrations of Ag, As, Ba, Cu, Pb, Sb and Zn when analyzed. The mean concentrations of these elements in the tailings were 29.8, 285.4, 54000, 57.7, 2687.5, 179.0 and 2269.0 ppm, respectively. In the soil samples these decreased to 14.3, 96.9, 24700, 37.5, 1859.1, 168.5 and 815.7 ppm, respectively. Geochemical analyses demonstrated high levels of As, Pb and Zn which were above the intervention values set forth in the Andalusian Regulations for Contaminated Soils for As (>50 ppm), Pb (>500 ppm) and Zn (>2000 ppm). Column experiments and mineralogical studies suggest that the dissolution of sulfates and other secondary phases, accumulated in soils and waste-sites during the dry season, acts to control the mobility of metals. The elution curves obtained from column experiments showed a mobilization of Ba, Cu, Pb and Zn, while a low mobility was seen for Ag, As and Sb.

Reclamation of Degraded Landscapes due to Opencast Mining

“…Various analysis techniques, sampling and modeling schemes have been proposed and applied by researchers and according to Cuccu (2002), judgmental sampling, systematic and regular grid sampling, simple random sampling, stratified sampling, ranked set sampling, composite sampling can all be used as sampling method, and the techniques to achieve sampling operations may differ in function of number of sampling area and geometric features of sampling location. Navarro et al (2004) have carried out field and laboratory studies in order to investigate soil contamination derived from past mining activity in the Sierra Almagrera district in…”

Effect of Sludge Amendment on Remediation of Metal Contaminated Soils

“…The area comprising the Sierra Almagrera (Figure 1), located 90 km NE of the city of Almerí a (SE Spain), together with the Iberian Pyrite Belt and the Cartagena mining district, is the oldest metallurgical and mining area in the Iberian Peninsula [33][34][35]. During the nineteenth century and the early twentieth century, the smelting plants located along the Mediterranean coastline of the Sierra Almagrera district produced approximately 550,000 t of Pb and 3000 t of Ag.…”

Evaluation of Metal Attenuation from Mine Tailings in SE Spain (Sierra Almagrera): A Soil-Leaching Column Study

“…168 water table is generally located 20-30 m below the surface, 169 with annual and seasonal oscillations (Navarro et al 2004). …”

“…In addition, distilled water extracts from these 404 tailings indicated that the extractions were saturated to 405 supersaturated with calcite, dolomite, gypsum, jarosite, and 406 iron oxyhydroxides (Navarro et al 2004). Pore water sat-407 uration, with respect to jarosite, natrojarosite, and gypsum 408 McGregor et al 1998), and the possible 409 mobilization of metals from oxyhydroxides and sulfates, 410 have been detected in other tailings areas.…”

“…Most exploitation 28 occurred between 1838 and 1991, and focused on the 29 mining of Pb-Zn-Fe deposits in Sierra de Cartagena (Oen 30 et al 1975), the Pb-Ag (Fe, Ba) vein deposits in Sierra 31 Almagrera (Navarro et al 2004), the Pb-Zn-Ag vein 32 deposits in Mazarrón, and the Au-Ag epithermal deposits 33 in Rodalquilar (Arribas et al 1995). Metal mining has 34 ceased, but there are hundreds of abandoned mine sites 35 located near urban and agricultural areas.…”