Los indicios auríferos sobre la Fm Vegadeo en el corredor Navelgas-Trevías (Zona Asturoccidental-Leonesa)

In this paper, some results of practical interest regarding the gold mineralisation occurring in the northern area of the Navelgas gold belt (West Asturian-Leonese Zone) are presented. The mineral paragenesis of the Navelgas hydrothermal-type mineralization has been completed with the presence of arsenopyrite, lollingite, native Bi, bismuthinite, gersdorfite, violarite, monazite and parisite. Native gold, although scarce, is mainly associated with pyrite and asenopyrite. Pyrite, predominant sulphide, contains 625 mg-kg-1 of invisible refractory gold. Micro-analysis of trace elements in alluvial gold particles indicates the presence of several unknown primary gold showings, likely associated with quartz veins, in the upper basin of the Navelgas river. In the San Feliz area, about 12 km NE of Navelgas, refractory gold (727 mg-kg-1) has been identified in the goethite (pseudomorph of pyrite) within the eluvium overlying the Vegadeo Fm, suggesting the possible existence of deep mineralized areas.En este trabajo se presentan algunos resultados de interés práctico sobre las mineralizaciones de oro que aparecen en el sector norte del cinturón aurífero de Navelgas (Zona Asturoccidental-Leonesa). El indicio de Navelgas, el más importante del área de estudio, presenta una mineralización hidrotermal cuya paragénesis se ha completado con la presencia de arsenopirita, lollingita, Bi nativo, bismutinita, gersdorfita, violarita, monacita y parisita. El oro nativo, escaso, se asocia a pirita y asenopirita. La primera, mayoritaria, contiene 625 mg·kg-1 de oro refractario invisible. El microanálisis de elementos traza en oro aluvionar indica que en la cuenca alta del río Navelgas existen varios indicios, no conocidos, de oro primario, probablemente asociados a filones de cuarzo. En el área de San Feliz, unos 12 km al NE de Navelgas, se ha identificado la presencia de oro refractario (727 mg·kg-1) en la goethita (pseudomorfa de pirita) de los eluviones que se desarrollan sobre la Fm Vegadeo, lo que parece indicar la posible existencia de zonas profundas mineralizadas. En el área de San Feliz, unos 12 km al NE de Navelgas, se ha identificado la presencia de oro refractario (727 mg·kg-1) en la goethita (pseudomorfa de pirita) de los eluviones que se desarrollan sobre la Fm Vegadeo, lo que parece indicar la posible existencia de zonas profundas mineralizadas

Ecological and health risk assessments of an abandoned gold mine (Remance, Panama): Complex scenarios need a combination of indices

The derelict Remance gold mine is a possible source of pollution with potentially toxic elements (PTEs). In the study area, diverse mine waste has been left behind and exposed to weather conditions, and poses risks for soil, plants and water bodies, and also for the health of local inhab-itants. This study sought to perform an ecological and health risk assessment of derelict gold mining areas with incomplete remediation, including: (i) characterizing the geochemical distribution of PTEs; (ii) assessing ecological risk by estimating the pollution load index (PLI) and potential ecological risk index (RI); (iii) assessing soil health by dehydrogenase activity; and iv) establishing non-carcinogenic (HI) and carcinogenic risks (CR) for local inhabitants. Soil health seems to depend on not only PTE concentrations, but also on organic matter (OM). Both indexes (PLI and RI) ranged from high to extreme near mining and waste accumulation sites. As indicated by both the HI and CR results, the mining area poses a health risk for local inhabitants and particularly for children. For this reason, it will be necessary to set up environmental management programs in the areas that are most affected (tailings and surrounding areas) and accordingly establish the best remediation strategies to minimize risks for the local populatio

Riesgos ambientales asociados a la gestión inadecuada de residuos mineros en una explotación minera de oro, Remance, Panamá

Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

Empirical Model of Gaseous Mercury Emissions for the Analysis of Working Conditions in Outdoor Highly Contaminated Sites

The project SUBproducts4LIFE is a LIFE-funded research project that aims to demonstrate innovative circular economy concepts by repurposing industrial subproducts/waste (coal ash and gypsum from coal power plants, blast furnace slag, and steelmaking slag from steel factories) for the remediation of contaminated soils and brownfield areas associated with Hg mining on a large scale. Within the project, one of the objectives is related to worker safety by developing protocols and elaborating a guide of good practices to work under in these highly contaminated areas. The present research aims to assess the working conditions in an abandoned mine facility in terms of gaseous mercury in the environment, evaluating the main areas of the mine to ensure the health and safety of all workers and visitors. The study developed an empirical model for estimating the gaseous mercury concentration at any temperature with the target of scheduling the work to avoid occupational hazards. The research concluded that working without restrictions for temperatures under 15 °C in all the mine’s facilities is possible

Possibilities for Use of Coal Bed Methane & Coal Bed Mine in Asturias

There is a number of risk issues associated with CBM/CMM operations: sealing the mine shafts; pumping the mine water; evacuating air from the mine and air ingress into the mine. Our team has investigated the details of the initial phase of the business plan and, by extrapolation of key parameters, was able to form an opinion on the larger plan. The details investigated include: the methods to calculate the volume of gas entrapped in the coal; the sealing of the mine shafts to trap the gas escape; and the process to keep the mines pumped dry by removing the underground water that drains into the mine workings

New Equipment for Complementary Petrophysical Characterization of Rocks for Deep Geological Storage

The geological storage of CO2 in coal seams is an emerging option in the portfolio of mitigation actions for reduction of atmospheric greenhouse gas concentrations. A background study focused to the selection of favorable sites for CO2 geological storage are necessary steps, and in the selection of reservoirs for CO2 sequestration a complete petrophysical characterization of the sample is necessary. To complement the classical petrophysical parameters measured on the rocks of the geological formation with potential to be used to store the injected CO2, a new equipment has been designed and constructed to simulate at a laboratory scale the inter-action between the rock and the injected CO2, at different pressure conditions simulating depths of the geological formations up to 1000 m. The design and construction of this equipment allows us to investigate known physical and chemical processes that occur between the rocks store/seal and the fluid injected into geological storage. Essays focused to study the alterability of the rock in contact with CO2 either in subcritical or supercritical state, as well as essays for CO2 injectivity on the rock can be accomplished

Use & Re-Use of Water Resources in the Exploration Non-Conventional Hydrocarbons

The water cycle in hydraulic fracturing shows five stages that includes, from the water supply, the manufacture of the fracturing fluid, the injection, recovery of the flowback and water produced, and the management of the same. Finally, the case applied in the Asturian coal basin (ACCB) is analyzed for the development of the exploration and production of methane gas from coal layers (CBM)

CBM Resources Estimations for the Development of Coal Mine Methane in the Asturian Central Basin, Spain

New technological development and a best knowledge of the basin allow to have justified expectation to find coalbed methane reserves. Measurements of gas content in unexploited coal seams are made in order to estimate the CBM could revive the economic interest of the Asturian Central Coal Basin (ACCB). According to first estimations based on the studies accomplished, the minimum resources of coalbed methane in the whole of the Asturian Central Coal Basin are in the order of 25,000 Mm3 and the gas content of the coal seams range from 6 m3 to 14 m3/t. The introduction should briefly place the study in a broad context and define the purpose of the work and its significance