Historical Mining Research Articles

The future of mining in the Adria region: current status, SWOT and Gap analysis of the mineral sector

The Adria region which includes the countries of: Albania, Bosnia and Herzegovina, Croatia, Montenegro, North Macedonia, and Serbia, and corresponds to the Dinarides, northwesternmost Hellenides, and the Vardar zone, has a long history of mining. Here, the main strengths and challenges of the mineral sector of the Adria region were assessed using the following methodology: (1) presentation of the current status of mineral exploration and exploitation, (2) SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis on parameters including geological potential, economic environment, legal and regulatory framework, innovation and technology framework, environmental protection and land use planning, governmental and social potential, human resources and educational potential, (3) Gap analysis, and (4) integration of the results obtained in the development of a roadmap for the actions required to promote investments in the mineral sector in the Adria region. The main strengths of the regional mineral sector include the significant mineral potential due to a favourable geological setting, significant reserves, a long mining tradition, and active exploration areas, as well as a significant number of active and abundant mines and the availability of secondary raw materials. Nevertheless, there are many challenges that the mineral sector faces, such as difficulties in ensuring social acceptance, a lack of new exploration campaigns in many areas, estimation of resources or reserves that do not follow international codes and standards, regulations related to environmental issues in the mineral sector of Adria countries that do not comply with European legislation, and the limited availability of qualified technical, scientific and managerial personnel involved in the whole mineral cycle. Therefore, actions and measures such as awareness campaigns to highlight the significance of Raw Materials in the sustainable development of the region, further exploration, reserves calculation in alignment with internationally recognized codes, harmonization with spatial plans, and reforms to attract investors and capacity building programs should be taken for further development of the Adria region’s mineral sector in a sustainable manner.

Design and Fabrication of Flexible Paper-Based, Electrochemical Sensors to Detect the Presence of Heavy Metals in Ground Water

The history of mining and mineral extraction across the Navajo Nation has resulted in considerable contamination of the land and the groundwater resources, which is a significant environmental concern. Through a partnership between Navajo Technical University and Harvard University, we have designed and fabricated flexible, paper-based sensors in tandem with electrochemical techniques such as cyclic voltammetry, differential pulse voltammetry, and anodic stripping voltammetry to determine heavy metal concentrations in test samples. We have selected to fabricate paper-based electrochemical sensors because; they are low-cost, easy to make, environmentally friendly, and can be deployed for field testing across the Navajo Nation. We have demonstrated that our electrodes have successfully oxidized lead and arsenic oxide using the techniques stated above. The performance of our electrode is comparable to commercially available electrochemical sensors. Furthermore, the linear electrochemical response and sensitivity of our electrodes, for detecting heavy metals, makes them well suited for real-time sensors in field-testing applications.

Gray Gold: Lead Mining and Its Impact on the Natural and Cultural Environment, 1700–1840

Gray Gold: Lead Mining and Its Impact on the Natural and Cultural Environment, 1700–1840

Integrated geophysical, remote sensing and geochemical investigation to explore gold-mineralizations and mapping listvenites at Wadi Haimur, Eastern Desert, Egypt

Although the continuity of gold mining work since Pharaonic times till today, Wadi Haimur is still promised source for gold. Wadi Haimur is located in west Allaqi-Heinai-Suture (AHS), south Eastern Desert of Egypt. Gold mineralization is mainly confined within quartz-carbonate and sulphide-bearing quartz veins within sheared, altered rocks, while listvenitization plays a significant role in gold concentration along the Haimur area. Therefore, critical analyses of remote sensing data were applied to map alteration zones and delineate listvenites. Spatially enhanced images were processed to trace lineaments and weakness zones which may represent pathways of mineralized, ascended hydrothermal fluids. Ground geophysical, magnetic and geoelectric surveys were performed to study the depth-extension of mineralized bodies in the vicinity of the historical mines within Wadi Haimur. Interpretation of land-magnetic data indicates the presence of mineralized veins associated with narrow shear zones. Derivatives and high-pass filters were utilized to map shallow mineralized sources and deduce their trends. Upward continuation and low-pass filters were used to detect the deep sources. Depths to magnetic bodies were estimated using Power-Spectrum, Euler and inversion of single anomalies. Geochemical sampling was performed to test the results. According to the remarkable variation in resistivity and chargeability values of resistivity and induced-polarization tomography profiles, the subsurface lithology was classified and probable mineralized zones within the subsurface were detected. Encouraging results from regolith, trenching, rock-chip sampling and Reverse-Circulation (RC) drilling indicated the extension of auriferous anomalies within the bedrock. Good correlation of RC-holes auriferous anomalies depths and deduced depths from magnetic interpretation was revealed. HIGHLIGHTS Integrated geophysical, geochemistry and remote sensing data are used to delineate mineralized ore deposits. The estimated average depths of mineralized sources are 12.5, 48 and 463 m for shallow, intermediate and deep magnetic bodies, respectively. Massive sulphide-bearing zones ± gold concentrations were suggested for zones with low-resistivity and high-chargeability signatures.

Comprehensive Remote Sensing Technology for Monitoring Landslide Hazards and Disaster Chain in the Xishan Mining Area of Beijing

The Xishan coal mine area in Beijing, China has a long history of mining. Many landslide hazards, in addition to collapses and ground fractures, have occurred in this area. This study used multi-temporal satellite images to extract this region’s deformation information, identify landslides and analyze the deformation evolution process of these landslides. Taking the Anzigou ditch as an example, we investigate the “Quarry–Landslide–Mudslide” disaster chain model. We found that the landslide evolution process is closely related to the geological conditions, and usually goes through four stages: initial deformation, slope front swelling and collapsing, rear part connecting and rupturing, and landslide creeping. The surface deformation can be identified and tracked by high-resolution optical images and InSAR monitoring. Under the combined effects of rainfall and topographic conditions, medium and large landslides may occur and trigger a “Quarry–Landslide–Mudflow” disaster chain. The identification and analysis of these landslide hazards and the disaster chain help with geological disaster prevention, and provide reference for early identification and research of similar disasters.

Hydrogeochemical evolution induced by long-term mining activities in a multi-aquifer system in the mining area

The hydrogeochemical evolution of groundwater is related to and affected by long-term mining activities, which may deteriorate the quality of groundwater. The Fengfeng mine in Handan, North China has a 30-y history of coal mining with long-term mining activities and complex geological conditions, resulting in a complex hydrogeochemical environment in the mining region. In this study, the hydrogeochemical evolution mechanism of groundwater in a multi-aquifer system in the Fengfeng Mining Area was investigated using machine learning (self-organizing maps combined with K-means clustering) and sulfur and oxygen isotopes (δ34SSO4 and δ18OSO4). The hydrogeochemical characteristics of different aquifers in the mining area changed to different degrees after mining compared with the characteristics before mining. The spatiotemporal variations in groundwater components were found to be controlled by pyrite oxidation, gypsum dissolution, and carbonate dissolution, which are affected by mining activities. Pyrite oxidation primarily occurred in the Carboniferous thin-layer limestone aquifer (CLA) and Permian sandstone aquifer (PSA). The hydrogeochemical evolution in the Ordovician limestone aquifer (OLA), the main aquifer in the study area, was affected by leakage recharge from CLA and PSA caused by mining activities. The results showed that owing to the effects of long-term mining, the altered groundwater flow system affected the evolution of groundwater components in each aquifer, particularly the sulfate concentration. This study reveals a distinct hydrogeochemical evolution induced by mining activities, which can provide a basis for groundwater resource management in mining areas.

ASSESSMENT OF THE QUALITY OF RIVER SEDIMENTS IN BASELINE NATIONAL MONITORING STATIONS OF 12 COUNTRIES IN THE DANUBE RIVER BASIN

Fluvial sediment samples (river bottom sediment, suspended sediment and active floodplain/overbank) were collected in 2 baseline stations of the Transnational Monitoring Network for each of the 12 countries in the Danube Basin Region: Austria, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, Hungary, Republic of Moldavia, Montenegro, Romania, Republic of Serbia, Slovakia and Slovenia, according to a harmonized methodology. The sediment samples were analyzed for selected hazardous substances (HSs): 8 metals, 8 polycyclic aromatic hydrocarbons (PAHs) and 6 pesticides in an accredited laboratory selected as reference laboratory, as well as in national laboratories. Risk ratios were computed in order to compare the results to the Environmental Quality Standards listed in the European Directives, to the national threshold values in the Danube Basin, and to other available international European and American quality standards, and the risk ratios were classified as background, alert and intervention values for readily evaluation. Results show widespread metal(oid) (As, Cd, Cu, Hg, Pb, and Zn) contamination in the Danube Basin, most often associated with historic mining. Concentration values of Ni and Cr exceeding the thresholds are caused by the geological background (ultrabasic and metamorphic rocks in Bosnia and Herzegovina, Republic of Serbia and Romania). Concentration values higher than the thresholds for some of the PAHs (e.g. Fluoranthene) and sometimes for Total PAHs were also noted almost in every countries, caused by industrial activities, wastewater discharges or navigation on the Danube River. Pesticides were below the detection limit or below the legislative intervention thresholds at all national baseline sampling sites.

Mystery of gold placers

The authors review the gold mining history in Russia up to the second half of the 19th century when Russia became the global center of gold production. For instance, by the end of the 18th century, participation of Russia in the global gold production was less than 3 %, while in the mid-19th century, Russia produced more than a half of gold in the world. By the beginning of World War I, the gold holdings of Russia were the largest in the world—more than 1400 t. The article describes the goldbearing ore exploration activities starting from the times of Ivan the Great (1465–1505) when the Grand Duke applied to the King of Hungary with a request to send him skilled miners. The study explains while Russia first began mining “difficult” gold ore in the Urals in 1745 after Erofey Markov made a random discovery. Emphasis is laid on the discovery and commercial production of gold-bearing sand or placer gold. The authors emphasize the significance of that historical turning point in the gold industry of Russia and, certainly, the role the discoverer of gold placers L. I. Brusnitsyn. The article tells about the discovery, the exceptional persistence, perseverance and patriotism of that fine workman in mining, as well as the causes of that rather late discovery of gold placers. The might of the discovery made by Lev I. Brusnitsyn consisted in that the cost of placer gold was 4 times less than the cost of primary gold and the development of gold placers appeared to incomparable easier. The article describes how plots were woven around Brusnitsyn, and how his name was forgotten for more than 200 years after his death. Only in 2016 the image of the Master was recovered and a monument was built in his memory. The descendants have finally appraised the outstanding merits and personality of the mining craftsman in the practical solution of the century old problem connected with commercial production of placer gold. The article appreciates the contribution and role of L. I. Brusnitsyn and his disciples in discovery of gold placers in America, Australia, Alaska, etc., which drastically changed the world map of gold production. It is highlighted that for the whole history of gold mining, Russia produced around 18 thousand tons of the precious metal, the three fourth of which was placer gold. This is one of the most important conclusions of the historical research made by the authors of this article.

Spatiotemporal Differentiation Characteristics of Land Ecological Quality and Its Obstacle Factors in the Typical Compound Area of Mine Agriculture Urban

Mining activity combines industrialization, urbanization, and urban-rural integration in the compound area of mine agriculture urban. The land ecological environment has become a major hidden problem, restricting the sustainable development and ecological security of the region. It is imminent to understand the spatiotemporal differentiation characteristics of land ecological quality and its obstacle factors to scientifically carry out land ecological restoration. Here, the Macun coal area in Jiaozuo City, Central China, was selected for the case study, and an evaluation index system including four criteria layers of ecological foundation, structure, benefit, and stress was established. The multiperiod evaluation index data were acquired by utilizing remote sensing and geographic information system (GIS) technology. Based on the multi-objective comprehensive evaluation method, a comprehensive evaluation of land ecological quality was conducted, and the spatiotemporal differentiation characteristics of land ecological quality were explored. Moreover, an obstacle factor diagnosis model was constructed to confirm the spatiotemporal differentiation characteristics of obstacle factors affecting the change of the land ecological quality in the study zone. The results showed the following: (1) From 1980 to 2020, the land ecological quality index in the study zone showed a downward trend, and the proportion of the regional area with general and poor land ecological quality increased from 6.55% to 35.02%. (2) The areas with lower land ecological quality in each period of the study zone were mainly distributed in the mining areas with long mining history in the west and the areas with continuous urbanization and industrialization in the south. In contrast, the compound area of mine agriculture urban with short mining history in the east and southeast had higher land ecological quality. The aggregation of the land ecological quality index also showed similar spatial distribution characteristics. (3) The diagnosis results of obstacle factors showed that, due to the poor land ecological foundation and interference of mining activities, the land ecological quality of the mountain area in the north and west of the study area has been low. It is suggested that the land ecological quality of the area should be improved through measures such as terrain regulation, soil reconstruction, afforestation, and forest land conservation. Under the influence of mining activities and the continuous promotion of urbanization in the south of the study area, the regional ecological quality has been reduced. It is suggested that the regional land ecological quality should be improved by building ecological agriculture and ecological communities. The northeast of the study area is still in the mining area, and the ecological quality of the land tends to deteriorate. The ecological restoration in this area should be conducted by the combination of pre-mining planning, while-mining control, and post-mining restoration. The methodology of this study can provide reference for the identification and restoration of land ecological problems in the compound area of mine agriculture urban.

Geological and Mining Constraints on Historical Mine Production: The Case of Early Medieval Lead-Silver Mining at Melle, France

Early Medieval silver production for the Melle Pb-Ag deposit in western France has been estimated up to 15 tonnes per year over hundreds of years (Téreygeol, 2013) which would place it amongst the top silver mines of all times prior to the New World discoveries. However, this deposit has geological and mining characteristics economically unsuitable for substantial production, because it is thin, sub-horizontal and comprised of discontinuous pods. Furthermore, it is a Mississippi Valley type (MVT) base metal deposit, which are typically not major silver producers. There is no geological evidence for primary or secondary enrichment to generate silver-rich ore. Inaddition, the fact that Melle remained unmined in all later historical periods is enigmatic compared to the almost ubiquitous reworking of significant ore deposits elsewhere.In this paper, I discuss the geological characteristics, mining parameters, documented historical mining rates and workforce considerations, all of which can be used to constrain production estimates for Melle. The largest uncertainty for production estimates is the workforce size, which reflects scarce information about Carolingian Melle and its surroundings. A model employing realistic mining parameters and a workforce appropriate for a small mining village (100 miners/fire-setters, within a workforce of 250-300, from a settlement of at least 400-500) yields 52 tonnes of lead metal and 150 kg of silver per year. Doubling the workforce would double this estimate. Conversely, it could be half or less if mining was a seasonal activity between agricultural priorities such as harvesting and seeding.The previously claimed production rates require improbable mining assumptions together with at least 500 dedicated full-time miners and a population in the thousands. Furthermore, it would yield per capita silver productivity more than four times higher than in well-documented Early Modern operations that were leading silver deposits of their time. This seems unlikely. However, even at the much lower production levels, favoured here, Melle still might have been a major factor in the Carolingian economy, with its lead production perhaps as important as its silver.

Biomonitoring and assessment of toxic element contamination in floodplain sediments and soils using fluorescein diacetate (FDA) enzymatic activity measurements: evaluation of possibilities and limitations through the case study of the Drava River floodplain

The EU Water Framework Directive requires the monitoring and evaluation of surface water sediment quality based on the assessment of risk posed by contamination on the biotic receptors. Floodplain sediments are important receptors of potentially toxic element (PTE) contamination from the upstream catchment areas, and floodplains host climate-sensitive riverine ecosystems and fertile agricultural areas at the same time. This study investigates the effect of PTE contamination on microbial communities in floodplain sediments and soils using the fast, inexpensive and reliable fluorescein diacetate (FDA) method in order to estimate its applicability for sediment quality monitoring and preliminary toxicity-based risk assessment. Sediment and soil samples were collected from the actively flooded alluvial plain and the river terrace areas along a 130-km stretch of the large Drava River floodplain known to be widely contaminated by historical mining, smelting and the associated industry in the upstream Alpine region. Results of detailed data analysis show that the total microbial activity represented by the measured FDA values is related to PTE (As, Cu, Zn, Cd, Pb) concentrations, but this relationship shows significant heterogeneity and depends on the spatial location and on the soil properties such as organic matter content, dissolved salt and nutrient content, and it is specific to the toxic elements. Results show that some microbe species appear to be able to adapt to the elevated PTE concentrations in toxic soil micro-environments, over time. Despite the observed heterogeneity of microbial activity, the results revealed a breakpoint in the FDA dataset around the FDA = 3 FC (fluorescein concentration) value suggesting that microbial activity is controlled by thresholds.

Historical gold mining infectious disease epidemics

Lethal infectious disease epidemics have historically occurred in military, refugee and mining camps where crowded conditions promote the spread of enteric, respiratory and insect-borne infections. The early history of gold mines around Palmer River, Queensland in the 1870s, Kalgoorlie, Western Australia in the 1890s and Papua on the island of New Guinea in the 1910s are recounted specifically as it relates to infectious disease deaths. Despite large diagnostic gaps, it is likely that malaria was the predominant problem in Palmer River, typhoid in Kalgoorlie and bacillary dysentery in Papua. Nearly two-thirds of all recorded deaths in the Palmer River district from 1873 to 1883 were due to infections, predominately 'fevers'. Typhoid fever likely killed >2000 Australians in the early phases of the Western Australian goldfields in the 1890s. Severe dysentery outbreaks killed up to a majority of the local workforce in the Lakekema goldfields of Papua resulting in the colonial authorities stopping mining activity in the second decade of the 20th century. In the absence of public health measures and specific chemotherapy, large mortality rates in miners reflected the over-riding economic drivers of gold miners and their lack of any understanding of microbial disease and its interruption by public health measures. Similar infectious disease epidemics are likely to reoccur when large numbers of impoverished miners use low-technology methods to work alluvial gold deposits in conflict areas as has been seen in modern Africa.

Correlating floodplain geochemical profiles with archival historical mining records to establish depositional chronologies of river sediment

Chronological markers in fluvial sediments can provide useful information on geomorphic response to historic catchment disturbance, and help explain historic channel morphodynamics. We concentrate on the River Nent catchment in Northern England, which was heavily impacted by lead and zinc mining in the 18th and 19th centuries. We date a 2 m deep profile of fine (<2mm) floodplain sediments using ore extraction records, covering the period 1845 to 1913, based on a significant correlation between zinc concentrations and zinc-ore extraction (r = 0.78, n = 27; p < 0.01). These dates were constrained with a basal OSL date of 2.7 ± 0.3 ka (Agemin to Agemean 1.4–3.0 ka) and existing lichenometric dates for surface gravels. Earliest lead contaminated sediments at the base of the profile most likely resulted from Roman mining operations within the catchment. Local mine-worker population statistics were used to simulate pre-1845 lead ore extraction; where above-average peaks in lead concentration, recorded at the 125–130 cm, 105–110 cm and 95–100 cm horizons, were linked to respective peaks in lead ore extraction in 1825, 1850 and 1866. Estimates of historic sediment delivery volumes at a 0.062 km2 sink site at Blagill, approximately 6.5 km downstream of the headwaters to the Nent, were estimated through coupling the chronological markers with accumulated sediment thickness and reach area. Sediment delivery was seen to be strongly enhanced by phases of metal mining, with peaks between 1800 and 1825 reflecting the final stages of lead mining, and later between 1892 and 1895, reflecting the peak extraction of zinc. Although lag times between ore extraction peaks and sediment delivery to the Blagill site introduce uncertainty to the proposed chronology, we conclude that where good local mining statistics are available, our approach provides a useful alternative or may be used in conjunction with other commonly used methodologies.

Mineralogical association and geochemistry of potentially toxic elements in urban soils under the influence of mining

Polluted soil is an important source of exposure to potentially toxic elements (PTEs) for humans, especially in urban areas. We studied the fate of PTEs in the total (<2 mm) and fine (<50 µm) fractions of urban soils in playgrounds, passing areas, and vacant lots of the historic mining village of Minas de Riotinto in SW Spain. The mineralogical and chemical observations included analysis by scanning electron microscopy, electron backscatter diffraction, X-ray diffraction, chemical analysis of Al, V, Cr, Mn, Co, Ni, Cu, Zn, Rb, Sr, As, Cd, Ba, Tl, and Pb after acid digestion by Inductively Coupled Plasma-Mass Spectrometry and Sb by X-ray fluorescence.The total and fine fractions of natural and mixed (consisting of natural soils and aggregate pavements) urban soils have significantly higher concentrations of sulfide-associated PTEs (Ni, Cu, Zn, As, Sb, and Pb) and Ba in comparison to the aggregate pavements. Most of the natural and mixed urban soils surpass the regulatory levels set by the regional Government for As and Pb to declare a soil as contaminated. This work highlights the mineralogical source of PTEs in the urban soils. Primary geogenic sulfide minerals are prone to oxidation promoting dissolution of PTEs and acid generation in the future. Additionally, for the first time, we have described arsenian plumbojarosite and beudantite in urban soils which are abundant secondary phases under the circumneutral pH conditions, effectively retaining As and Pb. Inhalable small PTE-rich particles (<10 μm) are present in many soils in playgrounds and garden areas potentially posing health risk to residents upon dusting and resuspension in the air.

Valorizing (cleaned) sulfidic mine waste as a resource for construction materials

Proper management and storage of mine waste, e.g., tailings and waste rock, is one of the main issues that mining industries face. Additionally, there is already an uncountable amount of existent historical mine waste, which may, even centuries after the closure of the mine, still be leaching contaminants into the environment. One solution to minimize the risks associated with the mine waste, with also potential economic benefits, is through the valorization of the waste. This can be done by first recovering valuable metals and removing hazardous contaminants. Then, the remaining residue can be valorized into green construction materials, such as geopolymers, ceramics or cement. For some mine waste materials, such as those with only trace levels of metals that are not economically viable to extract, the “waste” can be reused directly without this additional cleaning step. In the present study, mine waste originating from three different sites was characterized and compared with the cleaned mine waste (i.e., cleaned by bioleaching or flotation methods) and with different types of green construction materials containing 13–80 wt% (cleaned and uncleaned) mine waste. Particular emphasis was given to the mobilization of metal(loid)s from the mine waste and construction materials (i.e., ceramics, alkali-activated materials and cement) under different conditions, through a series of leaching tests (i.e., EN 12457–2, US EPA's Toxicity Characteristic Leaching Procedure, and a pH-dependent leaching test). The leaching tests were applied to either mimic current ‘natural’ conditions at the mining site, conditions in a landfill (end of life) or extreme conditions (i.e., extremely acidic or alkaline pH). Most of the original mine waste samples contain high levels of Pb (18–3160 mg/kg), Zn (66–10500 mg/kg), and As (10–4620 mg/kg). . The cleaning methods were not always efficient in removing the metal(loid)s and sulfur. In some cases, the cleaned mine waste samples even contained higher total metal(loid) and sulfur concentrations than the original mine waste samples. Based on the leaching studies, some alkali-activated materials, ceramics, and cement effectively immobilized certain metals (e.g., <0.5 mg/kg of Pb and <4 mg/kg of Zn). Also, longer curing times of the alkali-activated materials, in most cases, improved the immobilization of metal(loid)s. Additionally, for ceramics, the temperature at which the test pieces were fired (up to 1060 °C), also played a major role in decreasing the mobility of some metal(loid)s, while increasing others (e.g., As, potentially via the structural rearrangement of As and Fe). Overall, through this detailed characterization, the environmental impact from the mine waste to the downstream products was evaluated, determining which valorization methods are the most viable to close the circular economy loop.

Post-Coal Fantasies: An Actor-Network Theory-Inspired Critique of Post-Coal Development Strategies in the Jiu Valley, Romania

Romania is among the countries with a long history of coal mining, which intensified in the context of the industrialization and urbanization policies during the socialist period. During the post-socialist transition, mining units decreased considerably, with those considered economically unprofitable being restructured and eventually closed. This process, which began in the late 1990s, continues today with the increasing discussions about the transition from coal in Romania, the commitment to reduce greenhouse gas emissions, and the signing of the Paris Agreement, which stipulates the abandonment of coal by 2030. The Jiu Valley region is Romania’s most important mono-industrial area that developed exclusively around coal extraction. This article proposes an analysis of the social impact of reducing mining activity in this area based on actor-network theory. Recently, the discussions on the “Just Transition” in the Jiu Valley have culminated with the “Jiu Valley Economic, Social, and Environmental Development Strategy” (2021–2030) and the related Action Plan. This paper seeks to address the question: how were people “brought in” for the production of coal during socialism, how were they subsequently “pushed out”, and how challenging is it now for the Jiu Valley strategy to reassemble a network to support the post-coal transition? Our analysis helps to understand, in an innovative way, the challenges of the Jiu Valley Strategy as a mismatch between a creative and entrepreneurial city model on the one hand and the ruralized/small urban (former mono-industrial) conditions prevailing in the Jiu Valley on the other. We thus provide a critical analysis of the strategy as one that is conceptually wedded to the large urban center model and applies the just transition framework in a decontextualized way. We emphasize the role of the dismantling of coal production in the narrowing of the space of possibilities of change brought about by the just transition. Using the published literature on the Jiu Valley, we also show what broader lessons can be drawn from this case for similar transition processes in Central and Eastern Europe.

Urban Air Quality Monitoring in Decarbonization Context; Case Study—Traditional Coal Mining Area, Petroșani, Romania

Humanity is a fossil-fueled civilization with a large influence on the environment. The World Health Organization (WHO) has pointed out that air pollution is now the single biggest environmental threat to human health. The air quality in Petroșani, a traditional mining region from the Jiu Valley bituminous coal basin, Romania, is rarely debated; however, it is not often investigated. In this paper, the main air pollution sources of Petroșani are identified and the performed measurements emphasize the air quality in the area of its transit road. The monitoring program set out the objectives, parameters, and points of the monitoring system, as well as the frequency and duration of the program and other monitoring parameters. The equipment used was provided by the National Institute for Research and Development in Mine Safety and Protection to Explosion from Petroșani, within an institutional partnership with the University of Petroșani. The monitoring of the air quality parameters was conducted from March to July 2020, at six points located on the road that crosses the city. It was thus possible to capture a variety of concentrations of the monitored parameters in different weather conditions to determine the air quality in this area. Based on the variation of the measured values in one of the most important historical Romanian bituminous coal mining basins, the preliminary results suggest a worsening of local air quality parameters in relation to the decarbonization process.

Gaseous Mercury Exchange from Water-Air Interface in Differently Impacted Freshwater Environments.

Gaseous exchanges of mercury (Hg) at the water–air interface in contaminated sites strongly influence its fate in the environment. In this study, diurnal gaseous Hg exchanges were seasonally evaluated by means of a floating flux chamber in two freshwater environments impacted by anthropogenic sources of Hg, specifically historical mining activity (Solkan Reservoir, Slovenia) and the chlor-alkali industry (Torviscosa dockyard, Italy), and in a pristine site, Cavazzo Lake (Italy). The highest fluxes (21.88 ± 11.55 ng m−2 h−1) were observed at Solkan, coupled with high dissolved gaseous mercury (DGM) and dissolved Hg (THgD) concentrations. Conversely, low vertical mixing and saltwater intrusion at Torviscosa limited Hg mobility through the water column, with higher Hg concentrations in the deep layer near the contaminated sediments. Consequently, both DGM and THgD in surface water were generally lower at Torviscosa than at Solkan, resulting in lower fluxes (19.01 ± 12.65 ng m−2 h−1). However, at this site, evasion may also be limited by high atmospheric Hg levels related to dispersion of emissions from the nearby chlor-alkali plant. Surprisingly, comparable fluxes (15.56 ± 12.78 ng m−2 h−1) and Hg levels in water were observed at Cavazzo, suggesting a previously unidentified Hg input (atmospheric depositions or local geology). Overall, at all sites the fluxes were higher in the summer and correlated to incident UV radiation and water temperature due to enhanced photo production and diffusivity of DGM, the concentrations of which roughly followed the same seasonal trend.

Accumulation of As and Pb in vegetables grown in agricultural soils polluted by historical mining in Zacatecas, Mexico

Accumulation of As and Pb in vegetables grown in agricultural soils polluted by historical mining in Zacatecas, Mexico

Assessment of asbestos fiber contamination in lake sediment cores of the Thetford Mines region, southern Quebec (Canada)

• Lake sediments of the Thetford Mines region contain high asbestos concentrations. • Stratigraphic asbestos concentrations vary in accordance with mining history. • Asbestos mining waste erosion still today releases high amounts of asbestos fibers. • Asbestos fibers are transported over at least 25 km by the Bécancour River. The Bécancour River in southern Quebec (Canada) has evolved under the influence of the long asbestos mining history of the Thetford Mines region (1877–2011 Common Era; CE). This river originates at the outflow of Lake Bécancour, flows through the old mining sites, and then widens to successively form Stater Pond, Trout Lake, Lake William, and Lake Joseph (25 km from the closest mine). Our objective was to assess asbestos fiber contamination in dated sediment cores retrieved at these sites by means of transmission electron microscopy. Chrysotile was the most abundant form of asbestos identified in the samples. Asbestiform actinolite and tremolite were also found. Our results revealed that precolonial sediments deposited at 4 out of the 5 study sites naturally contained asbestos fibers (up to 3.5 wt%), with mass accumulation rates historically reaching up to 1.0 mg cm −2 yr −1 . However, fiber concentrations were greatly enhanced in the anthropogenic horizon of all sediment cores. The highest concentrations (up to 6.9 wt%) were found in layers from Stater Pond and Trout Lake deposited during the maximum of regional mining activities (1945‒1980 CE). Likewise, reconstructed mass accumulation rates indicated that asbestos fiber influx peaked (up to 38.6 mg cm −2 yr −1 ) during this epoch in all water bodies located downstream from Thetford Mines at magnitudes consistent with their proximity to the mining sites. They decreased after 1980 EC (≤ 24.4 mg cm −2 yr −1 ) following the decline of regional mining activities and improvement of air quality. Modern sediments of all study sites (including upstream Lake Bécancour) were nevertheless still highly enriched in asbestos fibers (up to 4.4 wt%), which can be attributed to intensive mining waste erosion in the lake catchments. Our study highlights that asbestos fiber contamination is important and widespread in the Bécancour River basin, which raises human and ecosystem health concerns.