Nota sobre una localidad con pirita (Sta. Creu d'Olorde, Barcelona)

Se estudia la situación geolgóica y las características de yacimiento de una localidad con pirita (Santa Creu d'Olorde, Barcelona). Las muestras mineralógicas y petrológicas son estudiadas mediante las técnicas, de luz reflejada, difractometría y espectrografia por fluorescencia de rayos X.

Aggregate material formulated with MSWI bottom ash and APC fly ash for use as secondary building material

The main goal of this paper is to obtain a granular material formulated with Municipal Solid Waste Incinerarion (MSWI) bottom ash (BA) and air pollution control (APC) ash to be used as secondary building material. Previously, an optimum concrete mixture using both MSWI residues as aggregates was formulated. A compromise between the environmental behaviour and the economy of the process was considered. Unconfined compressive strength and abrasion resistance values were measured in order to evaluate the mechanical properties. From these results, the granular mixture was not suited for certain applications owing to the high BA/APC content and low cement percentages used to reduce the costs of the final product. Nevertheless, the leaching test performed showed that the concentrations of all heavy metals were below the limits established by the current Catalan legislation for their reutilization. Therefore, the material studied might be mainly used in embankments, where high mechanical properties are not needed and environmental safety is assured.

Contribución al conocimiento de la geología del depósito de Au-Cu de La Pava (Península de Azuero, Panamá)

The «La Pava» Au-Cu deposit is hosted by a vulcanosedimentary sequence, named Ocú Formation,developed in an island arc environment that resulted from the subduction of the Nazca Plate beneath the Caribbean Plate during the Cretaceous times. The deposit consists of disseminations and stockworks of pyrite and chalcopyrite accompanied by barite, quartz and carbonates. Three hydrothermal alteration zones have been recognized: silicic, argillic and propilityc, typical of gold-related high sulfidation systems. A supergenic alteration overprints the hydrothermal alterations developing a cap rich in silica and Feoxides. The detailed study of the Ocú Fm. indicates that the sulfides and the accompanying gold was formed in a submarine environment. Therefore we suggest that «La Pava» represents an Au-Cu hybrid deposit between high sulphidation epithermal and VMS types, which are found in volcanogenic massive sulphide environments.