RESUMEN
Dual and multi energy X-ray transmission imaging (DE-/ME-XRT) are powerful tools to acquire quantitative material characteristics of diverse samples without destruction. As those X-ray imaging techniques are based on the projection onto the imaging plane, only two-dimensional data can be obtained. To acquire three-dimensional information and a complete examination on topology and spatial trends of materials, computed tomography (CT) can be used. In combination, these methods may offer a robust non-destructive testing technique for research and industrial applications. For example, the iron ore mining and processing industry requires the ratio of economic iron minerals to siliceous waste material for resource and reserve estimations, and for efficient sorting prior to beneficiation, to avoid equipment destruction due to highly abrasive quartz. While XRT provides information concerning the thickness, areal density and mass fraction of iron and the respective background material, CT may deliver size, distribution and orientation of internal structures. Our study shows that the data provided by XRT and CT is reliable and, together with data processing, can be successfully applied for distinguishing iron oxide rich parts from waste. Furthermore, heavy element bearing minerals such as baryte, uraninite, galena and monazite can be detected.
RESUMEN
Because of the outdated methods of common landfill selection, it is imperative to reevaluate the usage suitability. To assess the suitability of the existing waste landfill in Zanjan, Iran, we have used a combination of the analytical hierarchy process (AHP) and GIS techniques, along with fieldwork surveys. Four major criteria and 12 subcriteria were considered, and the AHP was applied to assign the relative importance weights of criteria and subcriteria to each other. Finally, a landfill suitability map was generated and ranked based on the final suitability scores. The results show that the unsuitable areas are around Zanjan, in the middle parts of the plain. By contrast, the most suitable areas are uncultivated areas, located mostly in the west, north, and south. The results also indicate that the present landfill is a highly suitable site. After desk studies, geoelectrical surveys and infiltration measurements were conducted to make the final decision. Double-ring permeability tests confirm the landfill is an acceptable site. The electrical sounding shows that the leachate plume has a width of about ~ 450 m, spreads to a depth of about ~ 55 m, and migrates towards the northeast. Considering the groundwater depth, dry climate, and a low infiltration rate of the landfill soils, it can be concluded that leachate plumes will not contaminate groundwater within this decade. The proposed method can be implemented to reevaluate the suitability of any old operating reservoir such as oil reservoirs, petrol filling stations, heavy industrial tanks, and landfills, containing liquid hazardous materials.
