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"Abandoned mines"
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Image Mapping Accuracy Evaluation Using UAV with Standalone, Differential (RTK), and PPP GNSS Positioning Techniques in an Abandoned Mine Site
Global navigation satellite systems (GNSSs) provide a common positioning method that utilizes satellite signals to determine the spatial location of a receiver. However, there are several error factors in standalone GNSS positioning due to instrumental, procedural, and environmental factors that arise during the signal transmission process, and the final positioning error can be up to several meters or greater in length. Thus, real-time kinematic (RTK) correction and post-mission precise point positioning (PPP) processing technologies are proposed to improve accuracy and accomplish precise position measurements. To evaluate the geolocation accuracy of mosaicked UAV images of an abandoned mine site, we compared each orthomosaic image and digital elevation model obtained using standalone GNSS positioning, differential (RTK) GNSS positioning, and post-mission PPP processing techniques. In the three types of error evaluation measure (i.e., relative camera location error, ground control points-based absolute image mapping error, and volumetric difference of mine tailings), we found that the RTK GNSS positioning method obtained the best performance in terms of the relative camera location error and the absolute image mapping error evaluations, and the PPP post-processing correction effectively reduced the error (69.5% of the average total relative camera location error and 59.3% of the average total absolute image mapping error) relative to the standalone GNSS positioning method. Although differential (RTK) GNSS positioning is widely used in positioning applications that require very high accuracy, post-mission PPP processing can also be used in various fields in which it is either not feasible to operate expensive equipment to receive RTK GNSS signals or network RTK services are unavailable.
Journal Article
Tamsin and the dark
Tamsin Thomas has discovered that she is the Last Pellar, the ancestral protector of Cornwall, and she's the holder of a magical staff, which gives her the power to fly. But now, Tamsin must face a new and ancient evil. Deep in the disused mines of Cornwall, there is a dark power lurking. And very soon, Tamsin's brother starts to behave very strangely indeed. Tamsin will need all her courage to overcome this new danger.
Book
Mapping hazardous mining-induced sinkhole subsidence using unmanned aerial vehicle (drone) photogrammetry
Accurate subsidence inventory data, based on an understanding of local topography, are a crucial first step toward reliable subsidence prediction and mapping future subsidence hazards. However, conventional, human-based methods of surveying and mapping subsidence suffer from data omissions and errors due to problems regarding accessibility, safety, and manual digitization. This study employed unmanned aerial vehicle photogrammetry to compile an accurate subsidence inventory map of abandoned mine areas. A Phantom 2 Vision+ drone was used, which is inexpensive yet appropriate for detailed topographic surveying of small-sized mine sites with a history of subsidence. An autonomous flight plan was designed, taking into account the extent of target mapping areas. A series of 29 aerial photographs were obtained within 2 min; digitally georeferenced orthoimage and digital terrain model (DTM) with 5 cm resolution could be obtained by processing with coordinate information of pre-installed ground control points (GCPs) within 30 min. sinkhole-type subsidence, including locational information, was identified from the geocoded high-resolution orthoimage and the DTM, and its area and volume were calculated to be 427 m
2
and 2323 m
3
(length 25 m, width 23 m, depth 9.1 m), respectively, from its modeled shape. Contour lines (10 cm interval), slope, and curvature were produced using the DTM. Validation using the GCP locations showed an error of approximately 14 cm in the generated DTM, which was considered acceptable for subsidence mapping purposes. The proposed approach enables accurate, rapid, low-cost, and safe surveying and mapping, which complements conventional surveying methods at sites of mining subsidence.
Journal Article
The hiding place : a novel
\"Joe never wanted to come back to Arnhill. After the way things ended with his old gang--the betrayal, the suicide, the murder--and after what happened when his sister went missing, the last thing he wanted to do was return to his hometown. But Joe doesn't have a choice. Because judging by what was done to that poor Morton kid, what happened all those years ago to Joe's sister is happening again. And only Joe knows who is really at fault. Lying his way into a teaching job at his former high school is the easy part. Facing off with former friends who are none too happy to have him back in town--while avoiding the enemies he's made in the years since--is tougher. But the hardest part of all will be returning to that abandoned mine where it all went wrong and his life changed forever, and finally confronting the shocking, horrifying truth about Arnhill, his sister, and himself. Because for Joe, the worst moment of his life wasn't the day his sister went missing. It was the day she came back\"-- Provided by publisher.
Book
Environmental assessment of heavy metal pollution in the polymetallic district of Kef Oum Teboul (El Kala, Northeast Algeria)
To the best of our knowledge, this study is the first to focus on the environmental assessment of heavy metals in the abandoned mining district of Kef Oum Teboul (KOT), which is located in the northeastern part of Algeria in an area classified by Ramsar as a Biosphere Reserve since 1990. KOT was one of the primary deposits of copper in the last century, and its releases are stored as dams that seriously threaten the environment. To assess the degree, distribution and sources of contamination approximately the mining area, liquid and solid samples were collected from the mining waste, the soils, and the stream sediment. The samples were analyzed to determine the pH, conductivity and contents of heavy metals (Pb, Zn, Cu, and Cd). The mining areas are characterized by high contents of heavy metals that exceed all norms, and the metal contents significantly decrease at significant low distances from these sources. According to the statistical methods used in this study (I-Geo, Pi, RI), the stream sediments and the soils are uncontaminated to moderately contaminated by Cu and Zn, moderately contaminated by Pb, and extremely contaminated by Cd.
Journal Article
River of lost souls : the science, politics, and greed behind the Gold King Mine disaster
\"In 2015, a flood of thick yellow sludge from a long-abandoned mine in Silverton, Colorado, made headlines as it flowed down the Animas River towards the Navajo Nation and the mighty Colorado River. Perhaps the most charismatic environmental disaster of our time, the Gold King Mine spill illustrates the devastating potential waiting in hundreds of abandoned mines throughout the Rocky Mountains. With disarming storytelling, award-winning journalist Jonathan P. Thompson unearths a litany of impacts wrought by a century and a half of mining, energy development, and fracking in southwestern Colorado. Amid these harsh realities, Thompson explores how a new generation is setting out to make amends\"--Back cover.
Book
Mineralogy and Geochemistry of Rural Road Dust and Nearby Mine Tailings: A Case of Ignored Pollution Hazard from an Abandoned Mining Site in Semi-arid Zone
Abandoned mine tailings are considered as one of the main sources of potentially toxic elements. Because of the lack of supervision, particularly from small-scale or artisanal mining, abandoned tailings have become part of the natural landscape, especially in rural areas from developing countries. Abandoned mine tailings represent a latent problem in terms of the possible affectations to human health and the environment. An example of this is the small-sized (~ 200 × ~ 300 m) abandoned mine tailings located ~ 500 m south of San Felipe de Jesus town, Sonora, in northwestern Mexico. The mineralogy determined in mine tailings samples consists of divalent hydrated metal sulfates (rozenite, starkeyite, kieserite, szomolnokite and epsomite), trivalent hydrated metal sulfates (coquimbite) and divalent-trivalent hydrated sulfates (copiapite), which are highly soluble efflorescent minerals associated with acid mine drainage. Rozenite was detected in road dust samples, evidencing that dust is dispersed and transported from abandoned residues. In order to assess the possible impact of the tailings (un-oxidized, oxidized, efflorescent minerals), concentrations of potentially toxic elements (total and soluble fractions) in samples from mine tailings, unpaved road soils and road dust from San Felipe de Jesús were determined. Average concentrations (ppm) of potential toxic elements in mine tailings samples ranged from 16,756–1306 (As), 665–98 (Cd), 5691–338 (Cu), 14,162–832 (Pb), 492–82 (Sb), 176,219–8285 (Zn). Enrichment factors determined in mine tailings, agricultural soils and road dust exhibit similar patterns, differing only in level of enrichment, which also confirms the dispersion of potentially toxic elements toward surroundings. Contamination Index (CI) and Hazard Average Quotient (HAQ) were calculated in mine tailings to assess potential contamination associated with potentially toxic elements dispersed by aeolian and/or hydric processes, respectively. The CI values suggest that mine tailing materials have a high potential for polluting soils and sediments. Semi-arid conditions of the region favor the suspension and transport of contaminants, potentially affecting surrounding agricultural fields and population. The HAQ values from efflorescence minerals and mine tailings indicate that potential of toxicity is very high, and might affect the quality of water (groundwater and surficial) in the region. CI and HAQ can provide a good estimation of pollution hazards associated with the abandoned mine tailings in the San Felipe de Jesús area.
Journal Article
Advances and Future Directions in Monitoring and Predicting Secondary Surface Subsidence in Abandoned Mines
In recent years, the prolonged exploitation of coal resources has led to the depletion of coal reserves in some mining areas, resulting in the closure of certain mines worldwide. After mine closures, the fractured rock masses in abandoned mine cavities undergo weathering and degradation due to factors such as stress and groundwater, leading to reduced strength. This change alters the stress distribution and load-bearing capacity of the fractured rock within the abandoned voids, resulting in secondary or multiple deformations on the surface, which pose significant potential threats to surface infrastructure and public safety. Research into the mechanisms, patterns, and predictive methods of secondary surface subsidence in closed mines is thus of great theoretical and practical significance. Based on a literature review and practical monitoring experience in closed mine sites, this study systematically examines and analyzes the current state of secondary surface subsidence monitoring methods, formation mechanisms, spatiotemporal distribution patterns, and prediction methods in closed mines, as well as existing challenges. Initially, we compare the advantages and limitations of conventional surface deformation monitoring techniques with remote sensing techniques, emphasizing the benefits and issues of using InSAR technology for monitoring surface subsidence in closed mines. Next, by reviewing extensive data, we analyze the formation mechanisms and spatiotemporal evolution of secondary surface subsidence in closed mines. Building on this analysis, we discuss numerical and analytical methods for predicting secondary surface subsidence mechanisms in closed mines, evaluating the strengths and weaknesses of each approach. Predictive models for surface subsidence and uplift phases in the longwall collapse method are presented based on the constitutive relationships of fractured rock masses. Finally, the study highlights that the mechanisms and patterns of surface subsidence in closed mines represent a highly complex physical–mechanical process involving geological mining environments, fractured rock structures, constitutive relations, deformation characteristics, hydro-mechanical interactions, and groundwater dynamics, underscoring the need for further in-depth research.
Journal Article
Contamination, sources and environmental risk assessment of heavy metals in water, sediment and soil around an abandoned Pb mine site in North East Morocco
Metal Mining Contamination is a widespread problem in the world. However, the assessment of abandoned mine metal contamination, especially in Morocco, has not been studied sufficiently. In this study, a total of 83 samples of water, sediments, and soils were collected to investigate the concentrations of heavy metals (HMs) around an abandoned mining area, named: Zeïda in North East Morocco. Furthermore, geochemical mapping of these elements has been also conducted. The contamination and environmental risk introduced by the accumulation of HMs has been assessed using numerous ecological indexes, such as: geo-accumulation (Igeo), Potential Ecological Risk Index and Modified Contamination Degree (MCd) to name just a few. Add to that the assessment of water quality using water quality assessment indexes. The results showed that all major elements and HMs of the river and its tributaries were within the Guidelines for Drinking-Water Quality (GDWQ), except for levels of HCO3−, and K+. The hydrochemical facies was dominated by calcium magnesium bicarbonate (CaMg–HCO3), and the concentrations changed in the range (µg/l): Zn: 14.78–152.00, Cr: 2.56–13.23, Cu: 0.96–12.35, Pb: 0.03–11.26, As: 0.98–3.24, Ni: 0.11–1.34 and Cd: 0.01–0.31, respectively. The spatial distribution of HM concentration and numerous ecological indexes in soil and sediment samples revealed that the highest values were located in and near the tailings, and declined downstream, which classified these sites as very highly contaminated and severely hazardous. Vertically, the soil concentration of HMs accumulated increasingly in relation to depth, and that in fact highlighted their potential mobility. HM concentrations (mg/kg) in sediments were in the range of: Pb: 43.79–9889.30, As: 104.57–289.00, Cr: 25.84–125.00, Zn: 40.78–121.75, Cu: 8.85–36.11, Ni: 1.99–21.00 and Cd: 0.10–0.46, respectively. While the average concentration in the three depths of soil (mg/kg) were in the range of: Pb: 27.00–11,400.00, Zn: 36.00–231.33, As: 42.33–172.00, Cr: 21.67–105.33, Cu: 18.33–143.33, Ni: 13.67–40.33 and Cd: 0.04–1.33, respectively. Multivariate statistical analysis indicated that HMs were related to the dispersion of tailings materials, with the exception of Ni and Cr which were related to lithological source.
Journal Article