Search Results (9)

Traditional mining activities in Zaruma-Portovelo (SE Ecuador) have led to high concentrations of pollutants in the Puyango River due to acid mine drainage (AMD) from abandoned waste. Dispersed alkaline substrate (DAS) passive treatment systems have shown efficacy in neutralizing acidity and retaining metals and sulfates in acidic waters, achieving near a 100% retention for Fe, Al, and Cu, over 70% for trace elements, and 25% for SO₄²⁻. However, significant solid residues are generated, requiring proper geochemical and mineralogical understanding for management. This study investigates the fractionation of elements in AMD precipitates. Results indicate that Fe³⁺ and Al³⁺ predominantly precipitate as low-crystallinity oxyhydroxysulfate minerals such as schwertmannite [Fe³⁺₁₆(OHSO₄)_12–13O₁₆·10–12H₂O] and jarosite [KFe³⁺₃(SO₄)₂(OH)₆], which retain elements like As, Cr, Cu, Pb, and Zn through adsorption and co-precipitation processes. Sulfate removal occurs via salts like coquimbite [AlFe₃(SO₄)₆(H₂O)₁₂·6H₂O] and gypsum [CaSO₄·2H₂O]. Divalent metals are primarily removed through carbonate and bicarbonate phases, with minerals such as azurite [Cu(OH)₂·2CuCO₃], malachite [Cu₂(CO₃)(OH)₂], rhodochrosite [MnCO₃], and calcite [CaCO₃]. Despite the effectiveness of DAS, leachates from the precipitates exceed regulatory thresholds for aquatic life protection, classifying them as hazardous and posing environmental risks. However, these residues offer opportunities for the recovery of valuable metals. Full article

In recent decades, geotourism has been presented as an alternative for the sustainable socioeconomic development of the community. In addition, it shows significant growth. Portovelo canton, located in the south of Ecuador, is characterised by a significant geological importance complemented by the mining culture and history interest, turning into the first mining centre. Mining is the main economic activity in the area. However, the development of illegal mining without technical considerations affects the canton and its surroundings. Faced with this problem, the need arises for alternatives to improve the inhabitants’ quality of life and protect their geological heritage. This work aims to propose a geotouristic route (GR) in the course of the Amarillo River through the characterisation and quantitative assessment of 10 interest sites (four geosites and six touristic sites), which enhance the geotourism development of the canton, including geoconservation strategies. The methodological process includes (i) characterisation of sites and GR proposal, (ii) sites and GR assessment using the Geotouristic Route Assessment Matrix method (GtRAM, acronym in Spanish) and Brilha method for geosites, and (iii) proposal of geotourism development and geoconservation strategies in a sustainability framework through the analysis of strengths, opportunities, weaknesses, and threats (SWOT). The results obtained from the proposed GR reflect that 60% of the proposed sites have a tourist interest classified as high, of which the Museo Mineralógico Magner Turner was the best-rated geoheritage element. Similarly, the high scientific, educational, and tourist values of the proposed geoheritage sites are highlighted. Strategies have been established to enhance the GR value: (i) Promoting geotourism through different activities and (ii) proposals for geoconservation and conditioning of geoheritage sites and tourist interest sites considering the geological and environmental impact. The methodology used in the study made it possible to establish geo-guidelines focused on local development, which are coupled with the knowledge of two main groups: Geo-experts and the community. Full article

The Zaruma-Portovelo mining district in Ecuador, and in particular, Portovelo City, is home to the oldest mining museum in the country. This museum, named Museo Mineralógico Magner Turner (MMMT in Spanish), is a centre that reflects, through its collections, the history and culture of this territory. This work aimed to evaluate the MMMT as a possible geosite by analysing its contributions to the geomining heritage of the Zaruma-Portovelo district, and thus, to enhance it and promote its collections as a geotouristic attraction. The work involved three phases: (i) describing the museum and its surroundings; (ii) a semiquantitative evaluation of the museum using the Brilha method and a geosites assessment model (GAM); and (iii) a qualitative evaluation using the Delphi and SWOT methodologies to define strategies and proposals for museum development. The results obtained by the semiquantitative evaluation of the geosite with the Brilha method reflect high scientific (330/400), educational (380/400) and touristic (365/400) appeal. The applied GAM shows the museum as a geosite with high principal and additional value, placing it in the Z₃₃ field of the global valuation matrix. In addition, the semiquantitative and qualitative evaluation made it possible to describe the importance of the museum and its collections in the development of the area. The study carried out qualified the museum as a mining site with an appropriate valuation, an example of ex-situ geological heritage conservation and a basis for geotourism development. Full article

Travel itineraries are fundamental in the development of tourism of a given area. Traditional thematic routes (e.g., architectural, archaeological) can be significantly improved and optimized by including geological and mining interest sites. The present study offers an analysis of the influence that inclusion of geosites or mining sites could have on the existing routes of the Zaruma-Portovelo region (Ecuador), together with a global assessment of these itineraries as the basis of fostering local development in communities of the region. The methodology consists of the following stages: (i) compilation of existing travel itineraries; (ii) analysis and assessment of those geosites and mining sites that are included in two geotouristic routes through the Spanish Inventory of Places of Geological Interest method (IELIG, acronym in Spanish), but have not been assessed previously; (iii) assessment of existing routes (two geotouristic routes and one geomining route) from a global perspective through the Geotouristic Route Assessment Matrix method (GtRAM, acronym in Spanish); and (iv) definition of strategies for the development and promotion of travel itineraries within the context of geotourism. According to the results of quantitative assessment, three new sites (both geosites and mining sites) were studied and their obtained score of interest was “High” (164/400). The existing routes achieved good results both from the geological-mining perspective “High” score of (189/400) and within a global context “Very High” score of (3.5/5). The quantitative assessment allowed us to propose improvement strategies to disseminate and use these itineraries to unfold sustainable development based on geotourism. Full article

In the last decade, in the mining district of Zaruma-Portovelo, there has been significant land subsidence related to uncontrolled mining activity. The purpose of this work was to carry out a surface and underground geomechanical characterization of a mining sector north of the city of Zaruma that allows the definition of potentially unstable areas susceptible to the mass movement. The methodology used consists of the following stages: (i) compilation of previous studies; (ii) surface and underground characterization of rocky material to establish its susceptibility to mass movement; (iii) interpretation of results; and (iv) proposal of action measures. Among the most relevant results, it stands out that 26.1% of the 23 stations characterized on the surface present conditions that vary from potentially unstable to unstable. In underground galleries, the studied mean values of the 17 stations indicate that the rock has a medium to good quality, representing a medium susceptibility to gallery destabilization. The results obtained for the surface areas (depths up to 50 m, where altered materials predominate) and the underground areas (depths > 50 m, where the alterations are specific) can be used to identify the areas with a more significant potential for instability. For both cases, it has been possible to define specific monitoring, control, and planning actions for sensitive areas. Full article

Mining and petroleum production are the source of many elements and base materials fundamental for our modern way of life. The flip side of these keystone industries is the environmental degradation they can cause if not properly managed. Metallic mining and petroleum production can contaminate the local ecosystem with sediments, chemicals used in the industrial processes and heavy metals, part of the metallic ore or oil reservoir. The objective of this project was to analyze the spatial distribution of the presence of different potentially hazardous elements that make up the metallic deposits and oil reservoirs in Ecuador, focused mainly on artisanal and small-scale gold mining (ASGM) districts. Additionally, we were interested in analyzing this information under the local political and administrative contexts which are key to determining how likely it is that mismanagement of the local mineral deposits and petroleum exploitation projects will end up causing environmental degradation. An extensive and intensive literature search was conducted for information on the presence and concentration of 19 potentially harmful elements. We analyzed data on 11 metallic deposits throughout Ecuador and a major oilfield in the Ecuadorian Amazon basin. We used geographic information systems to analyze the spatial distribution of these reservoirs and their mineral compositions. The results indicated a widespread distribution and high concentration of elements potentially harmful for human health, such as mercury, cadmium and arsenic, throughout the metallic deposits in Ecuador. This is particularly true for long-exploited ASGM districts, such as Ponce-Enríquez, Portovelo-Zaruma and Nambija. This study highlights the importance of understanding geological diversity and its potential risks to better protect the biological diversity and public health of its inhabitants. Furthermore, we consider our work not as a call to stop ASGM mining nor petroleum production, but on the contrary as a strong call to plan every mining and petroleum production project considering these risks. Moreover, our work is a call to action by the local government and authorities to stop corruption and fulfill their duties overseeing the activities of mining and petroleum companies, stopping illegal mining, helping ASGM communities to improve their environmental standards, finding alternative income sources and protecting the local environment. Full article

This study offers a detailed assessment of the geosites and mining sites present in the Zaruma-Portovelo mining district (Ecuador) through their qualitative and quantitative assessment. It shows up the potentiality of this area taking advantage of its geological-mining heritage. The methodological process includes: (i) compilation and inventory of all the sites within the study area with particular geological or mining interest; (ii) preparation of reports and thematic cartography, (iii) assessment and classification of the elements of geological-mining interest; (iv) SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis and TOWS (Threats, Opportunities, Weaknesses, Strengths) matrix preparation seeking strategies to guarantee the viability of geotourism. A total of 16 sites of geological interest and 11 of mining interest were identified. The 77% of these sites was proved to be of high and very high interest in scientific terms. Likewise, their susceptibility to degradation assessed from their vulnerability and fragility was found to be high or very high in the 30% of the cases. As for the protection priority, all the studied sites obtained a medium-high result. Finally, the study based on the SWOT-TOWS revealed the possibility of applying action strategies in order to facilitate the compatibility of geotourism with the current productive activities, despite the difficult situation in the study area created by mining activities. Full article

Mercury is a toxic metal and is used in small scale gold mining. In Portovelo, Ecuador, mercury has been an environmental and health problem for decades. The target of this study was to assess the mercury concentration in the urine of miners from Portovelo/Zaruma to establish a prevalence of high values. Eight hundred and sixty-five (865) urine samples were collected and analysed for their mercury content, using cold vapor atom absorption spectroscopy. The prevalence of high mercury values (>25 μg/L) was estimated. Forty-four (44) miners with mercury levels >15 μg/L filled in a questionnaire for characteristics and possible confounders, and were examined for intoxication symptoms to establish the ten points medical score sum. The median urine value was 1.8 μg/L; 78.3% of miners were below 7 μg/L and were not at risk of an intoxication, whereas 5.9% of miners exceeded the limit of 25 μg/L and were probable to experience intoxication symptoms. The medical score sum had a range of 2 to 8 points with a median of 6. The low prevalence of high mercury concentrations shows that the politics and techniques to eliminate the use of mercury are being successfully implemented. Further studies are needed to identify factors enabling this process. Full article

Optical image analysis (OIA) supporting microscopic observation can be applied to improve ore mineral characterization of ore deposits, providing accurate and representative numerical support to petrographic studies, on the polished section scale. In this paper, we present an experimental application of an automated mineral quantification process on polished sections from Zaruma-Portovelo intermediate sulfidation epithermal deposit (Ecuador) using multispectral and color images. Minerals under study were gold, sphalerite, chalcopyrite, galena, pyrite, pyrrhotite, bornite, hematite, chalcocite, pentlandite, covellite, tetrahedrite and native bismuth. The aim of the study was to quantify the ore minerals visible in polished section through OIA and, mainly, to show a detailed description of the methodology implemented. Automated ore identification and determination of geometric parameters predictive of geometallurgical behavior, such as grade, grain size or liberation, have been successfully performed. The results show that automated identification and quantification of ore mineral images are possible through multispectral and color image analysis. Therefore, the optical image analysis method could be a consistent automated mineralogical alternative to carry on detailed ore petrography. Full article