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The Pb-Zn-Fe ores of La Union, Spain, occur in an area of about 50 square km in three facial types of parageneses: (1) sulfides-carbonates-silica, (2) sulfides-carbonates-silica-greenalite-magnetite, and (3) oxides-hydroxides-sulfates-carbonates-silica. The distribution of the ore deposits shows a central zone with paragen.es.es (3) and (1) in direct association with late-Tertiary subvolcanic rocks and breccia pipes, an intermediate zone characterized mainly by paragenesis (2), and an outward zone characterized mainly by paragenesis (1). The occurrence of paragenesis (3) in the three zones at higher levels than parageneses (2) and (1) suggests a vertical zoning. A goochemical zoning with, from the central zone outward, Sn, Cu, Be, and Ba richer zones is also apparent. Mineralogical data indicate formation temperatures largely below 250øC and, within range of probable values of rs2 and fc•2, an increasing importance of fo2 toward the central and higher zones. The absence of crosscutting relations between deposits of different paragenetic type suggests a monascendant or facial zoning related to a center of Late Tertiary subvolcanic rocks and superimposed on the pre-Pliocene geology of the region. The ore deposits are syngenetic fissure veins in Late Tertiary volcanic rocks and epigenetic veins and peneconcordant replacement orebodies in older formations. Geological relations and the structure of the ore deposits indicate strong structural and lithological controls and shallow depths of formation within the zone of ground-water movement. o / a_ / // J z z

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Between 1957 and 1990, the Peñarroya Mining and Metallurgical Company (SMMPE) disposed about 60 million tonnes of tailings materials directly to the Mediterranean Sea. A substantial part of it (12.5 Mt) was dragged back by the sea currents progressively infilling the Portman Bay (Murcia, SE Spain), thus making the shoreline advance between 500 and 600 m seaward. The Roberto froth flotation plant processed mineral from manto-type deposits belonging to the Sierra de Cartagena-La Unión lead-zinc district. One of the mineral assemblages present in these deposits comprises greenalite, magnetite, sulfides, carbonates, and silica. Despite that magnetite recovery was undertaken by SMMPE between 1959 and 1967, we estimate that magnetite contained in the tailings hosts a substantial resource that could be as large as 2.3 Mt of iron ore. The ore contains magnetite ± hematite ± siderite. Tidal waves and sea currents led to gravimetric classification of the tailings material, with concentration of the dense iron oxides in the sandy fractions, eventually forming a coastal placer iron deposit. A major problem for magnetic separation is the intimate intergrowth between magnetite, hematite, and siderite. Besides, the sands contain large concentrations of Pb (0.27 %), Zn (0.72 %), and As (559 ppm).

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