Historical Mining Research Articles

Lay Religious Associations in Extractive Zones: A Case Study of Diamantina, Brazil

This article considers religion in extractive zones by focusing on a religious practice in an extractive zone, namely, an Afro-Brazilian Irmandade (Catholic lay religious association) devoted to Our Lady of Mercy in Diamantina, Minas Gerais, Brazil. It adopts approaches from history and cultural studies to examine art, architecture, archives, and material culture, and brings these methodologies into conversation with Mary Louis Pratt’s notion of contact zones, Charles Long’s connection between these zones and new religious practices, Eduardo Gudynas’ definition of extraction, and Macarena Gómez-Barris’ decolonial methodologies for approaching the study of extractive zones. This study is contextualized in the history of mining in Brazil, the connection between mining and enslavement of Africans in the Americas, and the enduring legacy of lay religious associations in Brazil. The article then examines the association’s church, focusing on its late 18th and early 19th century façade and the statues at its main altar, and its 19th and 20th century maintenance records. It suggests that the Irmandades are engaged in a unique religious practice that arises within an extractive region because of specific historical, political, and social reasons, and that they give their members a place within the existing structures even as they challenge them.

Uranium Mill Tailings Generation and Management Challenges

Uranium mining has been ongoing for the past 200 years, yet managing uranium waste remains a significant challenge. This difficulty arises due to strict regulations imposed on uranium-related industries, driven by the assumed health risks associated with radiation. As a result, much of the waste generated by nuclear industries is currently stored. In India, uranium mining and milling waste is stored that require large tracts of land and continuous monitoring. Given the high value of land in India and the potential expansion of uranium mining to meet net-zero emission targets, an effective solution for managing uranium mill tailings is urgently needed. Meanwhile, India's construction sector is rapidly growing that require a huge quantity of materials. This paper reviewed the history of uranium mining and mill tailings generation and propose that the construction industry could effectively utilize these tailings. This approach not only addresses resource scarcity but also promotes environmental sustainability by conserving natural resources, reducing ecological imbalances, and advancing a circular economy.

Uranium mining remediation, environmental assessment, and bureaucratic violence environmental sociology

ABSTRACT The US government has called for increased uranium mining to support nuclear energy as a replacement for fossil fuels. At the same time, remediating historical mines has been challenging, leaving Indigenous communities suffering as they fight for the removal of harmful mining waste from decades past. Examining two projects and their environmental assessments in the Navajo Nation, this study identifies how settler colonialism extends through state decision-making in the push for nuclear power. Promoting environmental justice, yet approving licenses for new mines and waste storage in Indigenous communities, constitutes a form of bureaucratic violence in which policies and procedures legitimate harm. State power is extended through claims of scientific legitimacy and participatory process, while defending decisions as just. The analysis of these processes shows how past land dispossession leads to forever environmental, ecological, and social damage under the guise of regulatory protection.

Interpretation of geological heritage on nature trails and geotrails in Geopark Banská Štiavnica and their online information availability

The inherent link between the mining history and culture in the region of Banská Štiavnica (Slovakia) and the unique geological and morphological heritage offers significant potential for the development of geotourism and educational trails, thus presenting the heritage to a wide spectrum of visitors. In recent years, online availability of information about such trails has become very important for the digital society that uses the internet and social networks daily. This article focuses on the development and online information availability of geotrails located in the territory of the first Slovak geopark, Banská Štiavnica Geopark. Results show that there are very few geoscience-based trails with limited online information available. By investing in effective on-site heritage interpretation and proper online promotion, the territory can become a premier geotourism destination.

Assessing Mercury Contamination Levels in the Sediments of Two Pyrenean Lakes

Mercury, a trace metal, is a persistent environmental pollutant that can be detected even in remote regions, including high-mountain lakes. This study examined mercury concentrations in the sediment of two lakes in the French Pyrenees, the Legunabens and Labant lakes. Sediment samples were collected using a Hon-Kajak Sediment Corer, and mercury concentrations were measured following the EPA 7473 method with a direct mercury analyzer (DMA-80). Mercury levels reached up to 283 ng g−1 in the Legunabens lake and up to 110 ng g−1 in the Labant lake, possibly linked to the mining history of the Ariège department and atmospheric deposition from distant sources. These findings indicate significant contamination, ranging from an 8% to 42% probability of generating adverse biological effects according to Canadian standards, and approximately 90% higher concentrations compared to average mercury concentrations in other Pyrenean lakes. Such contamination poses potential risks to aquatic life and the environment due to mercury’s toxicity and bioaccumulation in microorganisms.

Geochemical and mineralogical characterization and resource potential of the Namib Pb-Zn tailings (Erongo Region, Namibia)

In Southern Africa, historic mining and mineral processing of base metal deposits have almost exclusively focussed on the extraction of major metals, leading to the loss of remaining valuable raw materials into tailings dumps and waste rock piles. At the Namib Pb-Zn mine (Erongo Region, Namibia), historic base metal tailings deposits are present as unreclaimed exposed waste piles. The tailings comprise silt- (fraction A: d50 = 25 to 48 μm) to sand-sized (fraction B: d50 = 86 to 185 μm; fraction C: d5o = 210 to 230 μm) material and contain major concentrations of base metals (Pb av. 1.15 mass%, Zn av. 3.20 mass%), S (av. 9.95 mass%), as well as lower values of other metals (Cu av. 490 μg/g, Cd av. 133 μg/g, Ag av. 22 μg/g), and critical elements like Sb (av. 14.7 μg/g) and In (14.3 μg/g). Former mineral processing only targeted the extraction of galena and sphalerite. As a consequence, qualitative mineralogical composition of the tailings is similar to that of the primary ore. Ca-Fe-Mg(-Mn) carbonates, quartz, micas, chlorite, minor graphite, magnetite, and rare parisite relate to the former host rock and gangue matrix, whereas Fe-rich sphalerite, galena, magnetite, pyrite with minor pyrrhotite, rare arsenopyrite, marcasite, cassiterite, and accessory scheelite are original constituents of the primary ore. Reprocessing of such a material would be challenging, but a mixed Pb-Zn concentrate enriched in Cd and Ag might be obtained. In future, possible reprocessing of Namib tailings and associated disposal of wastes into an appropriately designed repository would not only generate valuable metal commodities, but such activities would also eliminate a major metal pollution source from the local environment.

Antimoniosis: Radiological Insights into a Rare Pneumoconiosis in Miners.

Pneumoconiosis describes diseases caused by the accumulation of inorganic dust particles in the lungs, leading to tissue damage. The diagnosis relies on a history of exposure and compatible radiological findings. We aimed to investigate the radiological findings in individuals exposed to antimony-inert dust relative to their working periods. Fifty-six symptomatic male antimony miners were retrospectively evaluated for demographics and chest computed tomography (CT) scans. The demographic and radiological data of patients with a history of antimony mining, who presented at our pulmonary clinic between June 2017 and June 2023, were analyzed according to the duration of exposure. The study included 56 male patients with a mean age of 58.5±13.02 years and a mean exposure duration of 13.63 ± 6.82 years. CT scans showed that 73.2% (n=41) had upper and middle lung zone involvement, and 55.4% (n=31) had extensive involvement. Micronodules with centriacinar ground-glass opacities were the most common finding (n=37, 66.1%), followed by nodular opacities with irregular margins (n=22, 39.3%) and solid micronodules (n=20, 35.7%). Patients with over 20 years of exposure had significantly higher rates of respiratory and cardiovascular disease (p<0.05). Increased exposure time correlated with more extensive parenchymal involvement and higher rates of calcification in mediastinal lymph nodes, solid micronodules, nodular opacities with irregular margins, honeycombing, and conglomerate mass appearance. Radiological findings in pneumoconiosis generally worsen with longer exposure. Given the scarcity of up-to-date information on antimony pneumoconiosis, further studies focusing on radiological findings and chemical analyses of those exposed to antimony mine dust are essential to identify related pathologies.

Mineralisation controls for the diverse Cape manganese occurrences, South Africa

Abstract The Cape Fold Belt, comprising folded sedimentary sequences from predominantly the Palaeozoic Cape Supergroup, hosts a multitude of manganese occurrences and mineral deposits, many of which were subject to historical mining activity. Although size, grade and quality issues negate their modern-day exploitation for the steel-making process, the mechanisms by which Mn has enriched at these sites holds scientific value for our understanding of low-temperature Mn (bio-)geochemical cycling. Deposits located within the Cape Fold Belt comprise structure-hosted Mn deposits and a little described class of Mn mound deposits associated with chalybeate thermal springs (temperature = 41 to 48°C). Although the relationships between the two remain tenuous, detailed study of both classes provides insight into the conditions that favour Mn accumulation in the near-surface and sub-aerial environments. Comparisons between the physicochemistry of manganiferous- and non-manganiferous thermal springs suggest that manganese solubility is favoured by warm, acidic and slightly reducing fluids with elevated salinity. Transport, and associated fluid focusing typically within highly permeable sandstone units, serves to locate Mn mineralisation in near-surface structurally-complex trap sites that provide both accommodation space and conditions that are sufficiently oxidising. Where manganiferous spring waters spill out at surface, oxidation is caused by contact with atmospheric O2 to form Mn mound deposits, and ambient Mn-oxidising microbiota (e.g., genus Ramlibacter, and members of Burkholderiales, Rhodocyclaceae, and Oxalobacteraceae) are likely to play a role in enhancing the kinetics of this process. Relative to the structure-hosted deposits, these Mn mound deposits are typically lower grade (higher iron content) and relatively friable (high porosity and fine grain sizes). Supergene and diagenetic processes can lead to localised upgrade of the Mn mound material, although typically not to ore grade.

Traceability and dispersion of highly toxic soluble phases from historical mine tailings: insights from Pb isotope systematics

Dispersion of potentially toxic elements associated with efflorescent crusts and mine tailings materials from historical mine sites threaten the environment and human health. Limited research has been done on traceability from historical mining sites in arid and semi-arid regions. Pb isotope systematics was applied to decipher the importance of identifying the mixing of lead sources involved in forming efflorescent salts and the repercussions on traceability. This research assessed mine waste (sulfide-rich and oxide-rich tailings material and efflorescent salts) and street dust from surrounding settlements at a historical mining site in northwestern Mexico, focusing on Pb isotope composition. The isotope data of tailings materials defined a trending line (R2 = 0.9); the sulfide-rich tailings materials and respective efflorescent salts yielded less radiogenic Pb composition, whereas the oxide-rich tailings and respective efflorescent salts yielded relatively more radiogenic compositions, similar to the geogenic component. The isotope composition of street dust suggests the dispersion of tailings materials into the surroundings. This investigation found that the variability of Pb isotope composition in tailings materials because of the geochemical heterogeneity, ranging from less radiogenic to more radiogenic, can add complexity during environmental assessments because the composition of oxidized materials and efflorescent salts can mask the geogenic component, potentially underestimating the influence on the environmental media.

Study on stability evaluation of goaf based on AHP and EWM—taking the northern new district of Liaoyuan city as an example

Throughout the history of coal mining in all countries of the world, large areas of goaf have been left behind, and sudden collapses and surface subsidence of large areas of goaf may occur, especially for mining areas with long mining cycles. The northern new district of the Liaoyuan mining area has been subjected to nearly half a century of mining activities, accompanied by a gradual accumulation of disasters, which have occurred frequently in recent years. In order to assess the stability of the goaf in the study area, this paper proposes a hybrid decision-making multi-factor integrated evaluation method. The distribution of underground goafs was determined using geophysical exploration techniques (seismic survey and transient electromagnetic method) and geological drilling exploration. First, an evaluation index system was established based on the specifications of the goaf, the ecological and geological environment, and the mining conditions; the system included 14 indicators. Two weight calculation methods, AHP-EWM, were employed to determine the comprehensive weight of each indicator by combining subjective and objective weights on the basis of improved game theory. Subsequently, the fuzzy comprehensive evaluation method was utilised to complete the stability rating of each block in the study area, and MapGIS and ArcGIS were employed to complete the drawing of the stability zoning map of the northern new district goaf. The study area was divided into three zones of stability, basic stability and instability, according to the critical value. These zones accounted for 23.03%, 36.45% and 40.52% of the total area of the study area, respectively. The comprehensive on-site investigation revealed a decrease in the size and number of collapse pits and the rate of damage to the houses from the unstable zone to the stable zone. This indicates that the results of the division are consistent with the actual situation. The classification results are consistent with the actual ground disaster situation, thus verifying the rationality and validity of the evaluation method. The results indicate that the stability of the study area is generally at the lower middle level.

Enrichment of dissolved metal(loid)s and microbial organic matter during transit of a historic mine drainage system

Water quality degradation by decommissioned mining sites is an environmental issue recognized globally. In the Ore mountains of Central Europe, a wide array of contaminants is released by abandoned under- and aboveground mining sites threatening the quantity and quality of surface and groundwater resources. Here, we focus on the less-explored internal pollution processes within these mines involving organic carbon and microorganisms in trace metal(loid)s mobilization processes. Over an 18-month period, we conducted hydrological and biogeochemical monitoring at the Reiche Zeche mine, a former lead-zinc-silver mine, in Germany, reaching 230 meters below ground, well below the critical zone. Our results show strong seasonal fluctuations in water availability, concentrations of metal(loid)s, pH, and dissolved organic matter (DOM) components across multiple depths. Excess metal(loid) presence during high flow conditions indicated mobilization behavior deviating from conservative dilution. Our findings reveal strong positive correlations between metal(loid) variability and pH (0.894), and between metal(loid) variability and the DOM fluorescent component C2 (-0.910), a proxy for microbial activity. Accordingly, the microbial processes may significantly contribute to the observed metal(loid) composition and fluxes. By elucidating the intricate roles of hydrological and biogeochemical factors in trace metal(loid) mobilization, our research offers a comprehensive framework for improving mine water management and remediation, potentially informing global environmental policies and sustainable mining practices.

Unintended Consequences of Urban Expansion and Gold Mining: Elevated Indoor Radon Levels in Gauteng Communities’ Neighboring Gold Mine Tailings

The province of Gauteng in South Africa has a rich history of gold mining, which has driven economic growth and urbanization. Gold mining has also created over 270 gold mine tailings (GMT), now surrounded by human settlements due to a housing shortage. These GMT pose a health risk as they harbor elevated uranium, which over time undergoes radioactive decay to produce radon, a known lung carcinogen. This study aimed to investigate the potential correlation between the proximity to gold mine tailings (GMT) and indoor radon concentrations in Gauteng’s residential dwellings. Volume activity of radon (VAR) inside 330 residential dwellings was measured in residential dwellings located proximally (&lt;2 km) and distally (&gt;2 km) to gold mine tailings using AlphaE radon monitors during winter. An interviewer-administered questionnaire was utilized to obtain data on factors that may influence indoor radon activities. Descriptive statistics and bivariate logistic regression analyzed the influence of proximity to gold mine tailings and dwelling characteristics on VAR. Furthermore, VAR was compared to the World Health Organization (WHO) radon reference level of 100 Bq/m3. Residential dwellings near gold mine tailings had significantly higher average indoor radon concentrations (103.30 Bq/m3) compared to the control group (65.19 Bq/m3). Residential dwellings proximal to gold mine tailings were three times more likely to have VAR beyond the WHO reference level of 100 Bq/m3. Furthermore, they had estimated annual effective doses of 2.60 mSv/y compared to 1.64 mSv/y for the control group. This study highlighted a concerning association between proximity to gold mine tailings and elevated indoor radon levels. Public health interventions prioritizing residential dwellings near gold mine tailings are crucial. Educational campaigns and financial assistance for radon mitigation systems in high-risk dwellings are recommended. Residents near gold mine tailings are encouraged to ensure continuous natural ventilation through frequent opening of windows and doors.

Genetic and morphological evidence support the specific status of the endemic Ericaandevalensis (Ericales, Ericaceae).

Assessing the taxonomic status of closely related taxa is crucial in plant systematics and can have important implications for conservation and human plant use. Ericaandevalensis Cabezudo & Rivera is a metallophyte endemic species from highly metal-polluted soils of SW Iberian Peninsula, an area with a mining history going back more than 5,000 years. Ericaandevalensis is closely related to Ericamackayana Bab., a northern Iberian species also present in western Ireland. The status of E.andevalensis as a species or subspecies subordinated to E.mackayana is subject to debate. Here, we assessed the genetic and phenotypic relationship between both species, including the population structure of E.andevalensis. We used high throughput sequencing to determine genome-wide Single Nucleotide Polymorphisms (SNPs), and morphometric analyses from 35 reproductive and vegetative traits. The morphological analysis showed at least eight characters that can discriminate the two species, from which ovary hairiness and the size of leaf glandular hairs were the most informative. Genetic analyses showed that each species formed a monophyletic cluster with full support, separated by an interspecific genetic distance >4-fold higher than intra-specific distance. Population genetic analyses of E.andevalensis shows that populations are highly structured, with the Portuguese one as the most isolated and less variable. These results support the recognition of E.andevalensis as a distinct species with a highly constrained ecological requirements and a narrow geographic distribution, but with a limited gene flow between populations. We discuss the implications of these outcomes in conservation policies and potential uses of E.andevalensis such as decontamination of polluted soils.

Microbial Mobilization and Reprecipitation of Transition Metals in Waste Rock from an Abandoned Pyrite Mine: Implications for Metal Recovery

Abstract The Pyrite Mines in Sulphide, Ontario are a collection of historic mine workings representing one of more than 6000 abandoned mines in Ontario. Historic mines are receiving renewed interest as potential sources of critical minerals for use in low carbon technologies. This study characterizes waste rock from the Pyrite Mines in the context of metal distribution, microbial activity, bioleaching, and acid mine drainage (AMD) bioremediation for the recovery of metals. Acidophilic Fe-oxidizing bacteria cultured from the waste rock produced schwertmannite [Fe8O8(OH)8−2x(SO4)x·nH2O] and ammoniojarosite [NH4Fe3(SO4)2(OH)6] with similar morphologies to those often observed in acidic sulfidic mine settings. Fe- and S-oxidizing bacteria found naturally in the waste rock were used in waste rock bioleaching column experiments that demonstrated AMD formation and metal mobilization. The columns produced acidic leachates (pH = 1.75) containing dissolved constituents, including sulfur (1577 mg/L), iron (547.7 mg/L), nickel (12.6 mg/L), manganese (7.3 mg/L), copper (2.3 mg/L), zinc (2.0 mg/L), chromium (1.5 mg/L), and titanium (0.7 mg/L). The proportion of metals successfully leached from the waste rock was variable, with leaching efficiencies calculated for nickel (31%), manganese (10.5%), iron (1.5%), chromium (1.4%), and titanium (0.02%). The leachates produced by the bioleaching columns were amended in subsequent bioremediation columns using sulfate reducing bacteria cultured from the mine site. Remediation efficiencies for elements of interest were calculated as cobalt (100%), chromium (100%), copper (100%), iron (90%), titanium (68%), nickel (52%), manganese (52%), and sulfur (43%). Mapping elemental distributions in thin sections from one of the bioleaching columns using synchrotron X-ray fluorescence microscopy revealed the heterogeneity of the waste rock. Iron was observed in both euhedral mineral grains, likely pyrite, and in secondary cements coating grains in the waste rock. Nickel, manganese, and chromium were primarily co-located with the iron. Titanium was primarily co-located with calcium in titanite (CaTiSiO5), making it challenging to target with bioleaching. This study demonstrates the heterogeneous nature of metal distribution in waste rock from this historic mine site. It indicates that successful metal recovery from legacy mine waste will require such materials to be treated as anthropogenic mineral deposits that require “exploration” and characterization much like naturally occurring ore deposits.

The Impact of Increasing Nickel Production on Forest and Environment in Indonesia: A Review

The history of nickel mining in Indonesia began in the Verbeek Mountains in Sulawesi in 1901. The finding of nickel and its extraction occurred in the Netherlands, making it the pioneering site for this ore. Also, the substantial rise in the extraction of natural resources like nickel through mining would inevitably profoundly influence forests, which serve as the core of the ecosystem for both flora and fauna. This study aims to determine the consequences of the growing nickel production on Indonesia’s forests and environment. It involves examining the alterations in the forests due to the increased nickel production and evaluating the broader environmental effects. The research method used in this research is a literature review. This technique seeks to analyze, assess, and interpret diverse research findings to examine them within the investigated subject’s framework. The research result of this investigation demonstrates that the escalating nickel production in Indonesia is detrimental to forests and the environment, leading to deforestation, degradation of habitats, and contamination of the air and soil. These alterations present immediate hazards to human well-being, such as respiratory problems and effects on agricultural output. It is crucial to evaluate and improve the methods used for nickel production and adopt sustainable management strategies to reduce the negative impacts on the environment and protect both the ecosystem and human welfare. Keywords: ecosystem pollution, deforestation, forest management, nickel mining, water pollution

New Geo- and Mining Heritage-Based Tourist Destinations in the Sudetes (SW Poland)—Towards More Effective Resilience of Local Communities

This paper explores several geotourist destinations in the mountainous area of SW Poland, either recently created or being developed right now, where the unifying theme is the emergence of a new site of interest in a place formerly inaccessible due to mining operations. We focus on five sites, including three in the territory of Land of the Extinct Volcanoes UNESCO Global Geopark, connected with the legacy of mining (coal, ores) and quarrying (solid rock, aggregates). For each locality, the history of mining is briefly outlined, followed by the presentation of its conversion into a tourist object and current use. The localities illustrate, at the same time, (a) various aspects of geoheritage and its connection with human activities, thus in line with the ABC concept promoted for geoparks and similar initiatives; (b) attempts to alleviate problems of abandoned mining grounds and their management; (c) different ways towards conversion of formerly inaccessible localities into tourist destinations; (d) ideas to increase the portfolio of (geo)tourist products at the regional scale, striving to achieve greater balance in the geographical distribution of sites of potential interest; and (e) a variety of current management challenges. Overall, it is argued that in each case, the emergence of a new site of interest is beneficial for the local community, as the visibility of the place is increasing, tourist visits grow, local identity is strengthened, and new employment opportunities arise, both directly and indirectly.

Legacy effects of historical gold mining on floodplains of an Australian river

The gold rush at the end of the nineteenth century in south-eastern Australia resulted in the mobilization and re-deposition of vast quantities of tailings that modified the geomorphology of the associated river valleys. Previous studies of contamination risk in these systems have either been performed directly on mine wastes (e.g., battery sand) or at locations close to historical mine sites but have largely ignored the extensive area of riverine alluvial deposits extending downstream from gold mining locations. Here we studied the distribution of contaminant metal(loids) in the Loddon River catchment, one of the most intensively mined areas of the historical gold-rush period in Australia (1851–1914). Floodplain alluvium along the Loddon River was sampled to capture differences in metal and metalloid concentrations between the anthropogenic floodplain deposits and the underlying original floodplain. Elevated levels of arsenic up to 300 mg-As/kg were identified within the anthropogenic alluvial sediment, well above sediment guidelines (ISQG-high trigger value of 70 ppm) and substantially higher than in the pre-mining alluvium. Maximum arsenic concentrations were found at depth within the anthropogenic alluvium (plume-like), close to the contact with the original floodplain. The results obtained here indicate that arsenic may pose a significantly higher risk within this river catchment than previously assessed through analysis of surface floodplain soils. The risks of this submerged arsenic plume will require further investigation of its chemical form (speciation) to determine its mobility and potential bioavailability. Our work shows the long-lasting impact of historical gold mining on riverine landscapes.

Drysfeydd y Cymoedd: 1 The Sub-Topographies of South Wales Valleys’ Industrial Crises

In Unclaimed Experience: Trauma, Narrative, and History, Cathy Caruth defines as traumatic our encounters not with life-threatening events but with those that cause a break in our perception of time. She explains that the memory of trauma is always fleeting, leaving connections with the time and place of traumatic occurrence fragile and obscure. Caruth’s definitions shape the work of contemporary geographers who argue that trauma is fundamentally unmappable. Does trauma’s relationship to space change when traumatization becomes repetitive and systematic? To explore systematic traumatization’s relationship to space, I adopt Lauren Berlant’s trauma definition as a crisis of ordinariness and revisit the South Wales Valleys region and its coal mining history as traumatic and contested. Using the exceptional Aberfan 1966 disaster as a starting point, I investigate a more “common” industrial crisis of the same period and explore its relationship to the industrial space by analyzing its discursive and drawing records. In this journey, sketching out the spatial qualities of the colliery’s maze is crucial for understanding the crisis’ occurrence, its belatedness and commemoration.

The Influence of Geotechnical, Geological and Mining Factors on the Formation of Sinkholes at Lubambe Mine, Zambia

Mining-induced sinkholes are a common feature in underground mines. Sinkholes usually disrupt mining operations and associated infrastructure when they occur. This paper presents a case study of the Lubambe copper mine, where nine (9) sinkholes have been reported on the eastern and southern limbs. The development of sinkholes has resulted in increased mining costs due to the closure of the 182 mL decline on the eastern limb and the 175 mL truck route on the southern limb. This study establishes the influence that poor ground formation, rock stability, geological structures, and inappropriate mining practices have on the formation of surface sinkholes. Assessment of ground condition was done by core logging, and borehole analysis was conducted using GEM4D-BasRock software to classify the rock mass quality based on RQD, RMR, Q-System and GIS. Assessment of the mining operational environment was focused on the effects of varying stope designs and sequencing on ground stability. Results of the study indicate that the formation of surface-induced sinkholes is attributed to historical mining in weak rock formation and weathered rock coupled with subsequent failure of unsupported stopes with stope height between 8 and 25 metres and less stand-up time of 7 days.

Thallium isotopic fractionation in soils from a historic Hg[sbnd]Tl mining area: New insights on thallium geochemistry

Thallium (Tl), a highly toxic heavy metal, which may pose significant environmental threats due to extensive discharge from anthropogenic activities. It is crucial to understand geochemical behavior of Tl in soils for initiating proper measures for Tl pollution control. For this purpose, transport behavior of Tl and its dominant factors in soils collected from a typically Tl-enriched depth profile, surrounding a historical tailing dump near an independent HgTl mine area in China, were investigated by using Tl isotope compositions. Results showed that an overall enrichment of Tl (48.68–375.21 mg/kg) was accompanied with As elevation (135.00–619.00 mg/kg) in the whole depth profile, and Tl and As exhibited co-migration behavior with Fe, S, K, and Rb. Geochemical fractionation of Tl unveiled by sequential extraction further indicated that Mn-/Fe-bearing minerals and clay minerals act as main hosts of Tl in the studied soils. Thallium isotopic composition and its fractionation pattern further revealed that the major contributors to high Tl levels in the depth profile were tailing and lorandite minerals, with mean contribution rate of 51.99% and 42.47%, respectively. These findings facilitate the understanding of Tl transport behavior in highly contaminated environment, providing valuable insights for developing new technologies in mining waste treatment and historical mine reclamation.