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Sweet, Michael L., Gwladys T. Gaillot, Gwenael Jouet, Tammy M. Rittenour, Samuel Toucanne, Tania Marsset e Michael D. Blum. "Sediment routing from shelf to basin floor in the Quaternary Golo System of Eastern Corsica, France, western Mediterranean Sea". GSA Bulletin 132, n. 5-6 (29 ottobre 2019): 1217–34. http://dx.doi.org/10.1130/b35181.1.
Testo completoAbstract (sommario):
Abstract How and when sediment moves from shallow marine to deep-water environments is an important and poorly understood control on basin-scale sediment dispersal patterns, the evolution of continental margins, and hydrocarbon exploration in deep-water basins. The Golo River (Eastern Corsica, France), its delta, canyons, and fans provide a unique opportunity to study sediment routing from source to sink in a relatively compact depositional system. We studied this system using an array of high-frequency seismic data, multi-beam bathymetry, and five cores for lithology and age control. Movement of sediment to deep water was controlled by interactions between the Golo River, the Golo Delta, and shelf-penetrating submarine canyons. Sediment moved to deep water when lobes of the Golo Delta prograded to the heads of these canyons, or when the Golo River itself flowed directly into one of them. Sand accumulated in canyons, deep-water channels, and submarine fans during glacial periods of low sea level, while mud was deposited throughout the slope, in the relatively short reach of leveed-confined channels, and in the mud-rich fringes around the sandy fans. During interglacial periods of high sea level, the basin was blanketed by mud-rich deposits up to 10 m thick interbedded with distinctive carbonate-rich sediments. Deposition rates in the basin ranged from 0.07 m/ka to 0.59 m/ka over the last 450 ka. Mud deposition rates remained relatively constant at ∼0.16 m/ka during all time periods, while sand deposition only happened during glacial periods of low sea level with an average rate of 0.24 m/ka. In addition to sea-level controls on sediment delivery, avulsions of the Golo River and its deltaic lobes preferentially routed sediment down either the North or South Golo canyons. Thus, while the larger, sequence-scale architecture of the basin is controlled by allogenic sea level forcing, millennial-scale autogenic processes operating on the shelf and in deep water shaped the distribution of sand and mud, and the internal geometry of the deltas and submarine fans that they fed. While some aspects of the Golo system are characteristic of steep, tectonically active margins, others such as the nature of connections between rivers and shelf-penetrating submarine canyons are observed in most margins with active submarine fans regardless of their tectonic setting.
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Molliex, Stéphane, Gwenael Jouet, Pierre-Henri Blard, Julien Moreau, Julie Demartini, Joep E. A. Storms, Claude Vella e Aster Team. "Quaternary evolution of the Golo river alluvial plain (NE Corsica, France)". Quaternary Geochronology 61 (febbraio 2021): 101115. http://dx.doi.org/10.1016/j.quageo.2020.101115.
Testo completo
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Forzoni, Andrea, J. E. A. Storms, Tony Reimann, Julien Moreau e Gwenael Jouet. "Non-linear response of the Golo River system, Corsica, France, to Late Quaternary climatic and sea level variations". Quaternary Science Reviews 121 (agosto 2015): 11–27. http://dx.doi.org/10.1016/j.quascirev.2015.04.021.
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Liu, Rui Ping, You Ning Xu, Jiang Hua Zhang, Hua Qing Chen, He Fang, Xian Li, Hai Ling Ke e Gang Qiao. "Accumulation and Environmental Risk on Heavy Metal Pollution in Bottom Sediments of Surface Waters in Xiao Qinling Gold Mine Belt, China". Advanced Materials Research 773 (settembre 2013): 862–68. http://dx.doi.org/10.4028/www.scientific.net/amr.773.862.
Testo completoAbstract (sommario):
Heavy metals accumulation in river sediments can reflect the environmental quality of river waters. Its of practical significance to study the accumulation level of heavy metals in river sediments and its environmental risk. this thesis study on the heavy metals accumulation in river sediments of three typical river of Xiao qinling gold mine area, and the results showed that the mercury, lead , zine, cadmium and copper elements are characteristic contaminations, respectively. In Shuangqiao river, the average values of mercury, lead , copper and zine were 94·72, 25.34, 3388.67, 376.77 and 675.90 mg·kg-1, the five elements show the larger variety in tong river and Shuangqiao river than the oher five rivers. respectively. The environmental risk assessment by using geoaccumulation index (Igeo) indicated that these seven rivers a high-very high rank environmental risk of heavy metals accumulation in river sediments, the environmental risk probability orders of seven river sediments is Tong river > Shuangqiao river> Xijian river > Yiluo river> Sha river > Zaoxiang river> Yangping river . and there was highest environmental risk in Eolian loess area. So There are the probability of achieving higher risk than now if local government wouldnt Adopt effectively manage measure river to rivers.
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Boguslavskiy, M. A., e S. O. Khudyakov. "Characteristics of native gold at Kosumnerskoe placer gold deposit (the Nether-Polar Urals)". Proceedings of higher educational establishments. Geology and Exploration, n. 5 (2 novembre 2018): 24–30. http://dx.doi.org/10.32454/0016-7762-2018-5-24-30.
Testo completoAbstract (sommario):
The paper presents the results of a study of heavy mineral concentrates of Kosumnerskoe gold deposit as well as the native gold from them. This gold deposit includes two gravel deposits. The granulometric composition, morphology, roundness, flatness, presence of intergrowths of gold with other minerals, as well as the character of the surface, the chemical composition and internal structure of gold, have been investigated. Based on these results, the placer gold of rivers Narta-Yu and Nester-Shor has been concluded to be similar in morphology, chemical composition and internal structure so it allows attributing them to a single type of motherload, which could be named as gold-polysulfide-quartz type. On the results of the analysis of two gold deposits of this field, the gravel deposit of the river Nester-Shor has been concluded to be elder than gravel deposit of the river Narta-Yu.
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Giusti, L. "The morphology, mineralogy, and behavior of u "fine-grained" gold from placer deposits of Alberta: sampling and implications for mineral exploration". Canadian Journal of Earth Sciences 23, n. 11 (1 novembre 1986): 1662–72. http://dx.doi.org/10.1139/e86-154.
Testo completoAbstract (sommario):
The morphology of a large number of gold grains from stream sediments of the North Saskatchewan River and the Athabasca River was studied, together with the partitioning of the placer gold between various size fractions.Two major morphological varieties of gold were observed: (1) flaky, scaly gold, with folded and hammered edges, and with crystals or crystal faces still visible on the surface; and (2) "sandwiched," droplike particles, sometimes toroidal. About 5% of both types of gold were found to be coated with "new," secondary gold.The size of the majority of the gold grains studied varies between 0.500 and 0.010 mm. The most frequent size range in the North Saskatchewan River is 0.125–0.250 mm, whereas in the Athabasca River it is 0.063–0.125 mm. An important fraction of the gold from both rivers is smaller than 0.063 mm.The average Corey shape factor (CSF) of the gravity-recovered gold increases as the particle size decreases, whereas the gold grains lost to the tailings indicate very low average shape factors (i.e., high degree of flattening). This apparent increase in CSF for the smallest fractions recovered when using mechanical techniques is due to the fact that the flaky gold particles are more difficult to recover than the more spherical ones. Moreover, the presence of a gold-rich rim on all the gold grains increases their hydrophobicity.The sampling procedure to be adopted in Alberta and, more generally, in glaciated terrains is discussed. In particular, the use of the −63 μm fraction for routine sampling of stream sediments is suggested.
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Ali, Munawar, Suhartoyo Hery e Suci Asriani Putri. "Mercury toxicity potential from artisanal and small scale gold mines in Lebong Regency, Bengkulu Province". E3S Web of Conferences 73 (2018): 06002. http://dx.doi.org/10.1051/e3sconf/20187306002.
Testo completoAbstract (sommario):
Artisanal and small scale gold mining (ASGM) is considered as the largest source of mercury pollution worldwide. The ASGM has been practiced for years in the area of Lebong Regency of Bengkulu Province. To extract gold from the ores, miners use a simple technique called Gelondong. This practice involves amalgamation process which forms amalgam, a mixure composed of mercury and gold. These amalgamation generates liquid and solid wastes (tailings) which still contain significant amount of mercury. Consequently, ASGM activities can potentially create mercury contamination of the environment, especially aquatic ecosystems. This study was aimed to investigate the concentration and distribution of total mercury in rivers to which wastes from ASGM communities in three villages of North Lebong District were dumped. Water and streambed sediments along the rivers were collected and brought to the laboratory for total mercury analysis. Data showed that total mercury was not detected in the river water but high in the river sediments with high variations among lactions from 0.11 to 110.37 mg kg-1. Apparently, total mercury tended to decrease with the distance from it source. High amounts of mercury in the river sediments could potentially spread to wider area and cause bioaccumulation in aquatic organisms, especially fish which can be dangerous to consume.
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Lawrence, Susan, James Grove, Peter Davies, Jodi Turnbull, Ian Rutherfurd e Mark Macklin. "Historical dredge mining as a significant anthropomorphic agent in river systems: A case study from south-eastern Australia". Holocene 31, n. 7 (25 marzo 2021): 1158–74. http://dx.doi.org/10.1177/09596836211003272.
Testo completoAbstract (sommario):
Bucket dredging to mine and extract gold and tin from rivers is a global industry that has had a range of negative effects on physical environments. These include the destruction of riparian soil profiles and structures, artificial channel straightening and loss of in-stream biodiversity. In this paper we evaluate the immediate effects and long-term consequences of bucket dredging on rivers in Victoria and New South Wales during the period 1900–1950. High quality historical sources on dredge mining are integrated with geospatial datasets, aerial imagery and geomorphological data to analyse the scale of the dredging industry, evidence for disturbance to river channels and floodplains and current land use in dredged areas. The study demonstrates that the environmental impact of dredging was altered but not reduced by anti-pollution regulations intended to control dredging. An assessment of river condition 70–100 years after dredge mining ceased indicates that floodplains and river channels continue to show the effects of dredging, including bank erosion, sediment slugs, compromised habitat and reduced agricultural productivity. These findings have significant implications for river and floodplain management.
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Taylor, G., R. Howes, L. Dulvenvoorden e V. Vicente-Beckett. "Downstream flow event sampling of acid mine drainage from the historic Mt Morgan Mine". Water Science and Technology 45, n. 11 (1 giugno 2002): 29–34. http://dx.doi.org/10.2166/wst.2002.0376.
Testo completoAbstract (sommario):
Numerous scientific reports concur that the Dee River is heavily impacted by acid mine drainage from the historic gold and copper mine at Mt Morgan, Central Queensland. The water quality along the Dee River, for 18 km downstream of the mine site to its junction with Fletcher Creek, is characterised by low pH, typically 2.8 to 4.2. With respect to metal concentrations, the Dee River has been described as one of Australia's most polluted rivers. Measurements of pH along the Dee River clearly demonstrated the movement of a slug of acidic water down the river during each of the four flow events between November 2000 and February 2001. Laboratory analysis of water samples collected during November indicated Al, Cu and Zn concentrations orders of magnitude above ANZECC guidelines. Fish kills occurred with each flow event and killed an estimated total of 26,000 fish.
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Borovec, Zdeněk. "Toxic Elements in River Sediments: Case Study Elbe and Its Tributaries". Geografie 100, n. 4 (1995): 268–75. http://dx.doi.org/10.37040/geografie1995100040268.
Testo completoAbstract (sommario):
Concentrations of 34 chemical elements in river sediments of Elbe and its tributaries were determined with help of instrumental neutron activation analysis, atomic absorption spectrophotometric method and some other specialized methods. Only particles smaller than 0.063 mm were examined. The results were compared with the local geochemical background. River sediments showed significantly high share of silver, gold, cadmium, copper, mercury, zinc, lead, arsenic, selenium, molybdenum, chromium, antimony, and tin. Sediments of Vltava, Jizera, Bílina, and Ploučnice rivers are the most polluted ones; on the other hand, Cidlina, Doubrava, and Chrudimka rank among the cleanest rivers. The degree of urbanization and industrialization play an important role, as well as the use of agricultural fertilizers. The influence of increased denudation as a result of acid pollutants has been recorded on some places, too.
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Kazakov, P. V. "Reconstruction of the Ancient River Network and Prospects of the Placer Gold Mineralization on the Southern Part of the Miass Intermountain Depression (South Urals)". Вестник Пермского университета. Геология 20, n. 1 (2021): 56–62. http://dx.doi.org/10.17072/psu.geol.20.1.56.
Testo completoAbstract (sommario):
We conducted the reconstruction of the ancient river network of the basins of the right tributaries of the Uy River Shartymka and Kiruda located in the southern part of the Miass intermountain depression within the Shartymskiy graben and its southern periphery. The sequence of placer formation from Cretaceous and Miocene karst-alluvial placers (Shartymsky graben) to the Eopleistocene and Neopleistocene has been established. In the valleys of the Shartymka and Kiruda rivers, areas of inherited development have been identified. This increased the reliability of estimation of the placer gold forecast resources. The most promising areas are recommended for geological exploration licensing.
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Rubinos, David, Luz Iglesias, Rosa Devesa-Rey, Francisco Díaz-Fierros e María Teresa Barral. "Arsenic release from river sediments in a gold-mining area (Anllons River basin, Spain): effect of time, pH and phosphorous concentration". European Journal of Mineralogy 22, n. 5 (2 novembre 2010): 665–78. http://dx.doi.org/10.1127/0935-1221/2010/0022-2061.
Testo completo
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Martinez, Gerardo, Stephen McCord, Charles Driscoll, Svetoslava Todorova, Steven Wu, Julio Araújo, Claudia Vega e Luis Fernandez. "Mercury Contamination in Riverine Sediments and Fish Associated with Artisanal and Small-Scale Gold Mining in Madre de Dios, Peru". International Journal of Environmental Research and Public Health 15, n. 8 (26 luglio 2018): 1584. http://dx.doi.org/10.3390/ijerph15081584.
Testo completoAbstract (sommario):
Artisanal and small-scale gold mining (ASGM) in Madre de Dios, Peru, continues to expand rapidly, raising concerns about increases in loading of mercury (Hg) to the environment. We measured physicochemical parameters in water and sampled and analyzed sediments and fish from multiple sites along one ASGM-impacted river and two unimpacted rivers in the region to examine whether Hg concentrations were elevated and possibly related to ASGM activity. We also analyzed the 308 fish samples, representing 36 species, for stable isotopes (δ15N and δ13C) to estimate their trophic position. Trophic position was positively correlated with the log-transformed Hg concentrations in fish among all sites. There was a lack of relationship between Hg concentrations in fish and either Hg concentrations in sediments or ASGM activity among sites, suggesting that fish Hg concentrations alone is not an ideal bioindicator of site-specific Hg contamination in the region. Fish Hg concentrations were not elevated in the ASGM-impacted river relative to the other two rivers; however, sediment Hg concentrations were highest in the ASGM-impacted river. Degraded habitat conditions and commensurate shifts in fish species and ecological processes may influence Hg bioaccumulation in the ASGM-impacted river. More research is needed on food web dynamics in the region to elucidate any effects caused by ASGM, especially through feeding relationships and food sources.
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Dramane Ouattara, Romuald Sonan Assi, Charles Koffi Boussou e Séraphin Kouakou Konan. "Diversity and degree of organization of the Ichthyofauna of two branches of the Bandama river in the Marahoue region (Central West of Côte D’Ivoire)". International Journal of Science and Research Archive 3, n. 1 (30 luglio 2021): 062–70. http://dx.doi.org/10.30574/ijsra.2021.3.1.0108.
Testo completoAbstract (sommario):
Diversity and Degree of organization of the ichthyological population of two tributaries of the Bandama River in the Marahoue region located in the center-west of Côte d'Ivoire were studied. Indeed, the two tributaries of the Bandama River that are Marahoue and White Bandama Rivers draining this region are subject to numerous disturbances, the main one being gold panning. Data collection was conducted from September 2019 to November 2020 from experimental and artisanal fisheries. The mesh sizes of the gillnets used for the experimental fishery varied from 10 to 40 mm mesh size. The results showed a dominance of the order Siluriformes represented by 6 families and 18 species in the Marahoue River against 4 families and 13 species in the White Bandama River. Also, the Shannon Index (H') values obtained in the White Bandama River (H' fluctuates from 2.26 to 2.33 bits/ind) are lower than those obtained in the River Marahoue (H' fluctuates from 3.02 to 3.14 bits/ind). Our results also highlighted the equitability. This index appeared relatively high in the Marahoue River (E varies from 0.77 to 0.80) compared to the White Bandama River (E varies from 0.5 to 0.57). Consequently, the Marahoue River appears to be more stable and has a good degree of organization of the ichthyological population compared to the White Bandama River.
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Percival, Annthea, Dina Khadija Benn e Denise A. Simmons. "Application of Geospatial Methods to support Water Quality Assessment in Guyana". Book of Abstracts: Student Research 1 (4 novembre 2020): 46. http://dx.doi.org/10.52377/dgpk5456.
Testo completoAbstract (sommario):
The Cuyuni and Mazaruni Rivers; major tributaries of the Essequibo River system in Guyana, feature gold and diamond mining that contribute to elevated levels of sediment loading. These excess sediments could endanger riverine ecosystems and indigenous communities. Water quality monitoring at these sites typically involves purposive in situ sampling and lab analyses, but this procedure can limit more comprehensive analysis. This research examined the usefulness of spatial interpolation for modelling distributions of surface water quality parameters.
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Hasibuan, Dwi Kartika Asih, Etty Riani e Syaiful Anwar. "Kontaminasi Merkuri (Hg) Pada Air Sungai, Air Sumur, Sedimen Dan Ikan Di Sungai Kuantan, Riau". Jurnal Pengelolaan Sumberdaya Alam dan Lingkungan (Journal of Natural Resources and Environmental Management) 10, n. 4 (9 febbraio 2021): 679–87. http://dx.doi.org/10.29244/jpsl.10.4.679-687.
Testo completoAbstract (sommario):
Illegal gold mining activities still frequently occur in the Kuantan River, which is one of the main rivers in the district of Kuantan Singingi, Riau. This activity causes environmental contamination of mercury (Hg). The objective of this research was to determine the contamination of Hg in river water, well water, sediment and fish (baung and kapiek) in the Kuantan River, Riau. Samples were taken at up, middle and downstreams of the Kuantan River. Mercury was analized by following APHA and Indonesian National Standard (SNI) methods. The results were compared with the quality standard of pollution. The results showed that average of Hg concentration in river water, well water, sediment and fish were 0,0325 mg/l, 0,0202 – 0,0231 mg/l, 0,2083 mg/kg, 0,1141 - 0,1224 mg/kg. Statistical analysis indicated that the concentration of Hg in river water, well water (middle and downstream) and sediment were above the quality standard, while in the samples of baung and kapiek were below the quality standard. Hg concentrations significantly increased from up to downstream locations in river water and sediment, Hg concentrations significantly increased in 2 community wells in middle and downstream locations, significant Hg concentration was found in kapiek caught in midstream locations, while there was no significantly at the Hg concentration of baung in the research location.
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Kochkurkina, S., e O. Orfinskaya. "Elite objects from kurgans on the Oyat River (Leningrad Oblast)". Archaeological News 31 (2021): 252–63. http://dx.doi.org/10.31600/1817-6976-2021-31-252-263.
Testo completoAbstract (sommario):
This paper considers fragments of elite objects of the 10th–12th century from kurgans on the Oyat River. It is silk textiles, embroidered collars, and gold-woven threads. The authors arrived at the conclusion about the high price of these objects and the hypothetical place of their manufacture. Possibly, there were centres to which silk cloths and silk threads were imported and where women, to the extent of their skill, embroidered some details of clothes, then distrib- uted throughout a considerable territory. The rather inconsiderable qualitative level of the embroidering does not allow us to attribute the collars from the Ladoga kurgans to products of the grand-ducal workshops but the expensive materials (silk and gold-woven threads) could not have been objects of simple domestic needlework.
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Fuog, R. M., K. C. Giberson e R. L. Lawrence. "Wastewater reclamation at Rancho Murieta, California; golf course irrigation with upgraded pond effluent meeting California's strictest requirements for wastewater reuse". Water Science and Technology 31, n. 12 (1 giugno 1995): 399–408. http://dx.doi.org/10.2166/wst.1995.0508.
Testo completoAbstract (sommario):
Rancho Murieta is an exclusive 1,400 ha (3,500 acre) master-planned golf-course-oriented community and is located approximately 39 km (24 miles) southeast of Sacramento, the capital of California. The community located along the banks of the Cosumnes River, one of the last pristine rivers in California, is situated in the great Central Valley of California which enjoys a Mediterranean-like semi-arid climate. The community has a present population of 3,500 people and is projected to have an ultimate population of 15,600. The Rancho Murieta Community Services District provides wastewater collection treatment and disposal services, among others within the community. In the early 1980s, the District obtained 55 ha (135 acres) of land for a wastewater treatment facility from the original developer of the community. Despite the immediate proximity of the plant to the Cosumnes River, the District was not allowed to discharge any plant effluent to the river. In favor of preserving the pristine qualities of the river, a “zero discharge” was required. Therefore, the District had to provide for some form of reuse of its effluent, a land disposal alternative. After considerable study, a plan was developed to integrate the community's two proposed championship golf courses into a comprehensive wastewater reclamation program. In addition to significantly decreasing the demand for treated domestic water within the community, a comprehensive program to irrigate the golf courses with reclaimed wastewater would also significantly lower the summertime demand for water from the river, thereby providing increased flows to downstream agricultural users along the river, a true “win-win” situation for all parties concerned. In order to provide treatment to an acceptable level for irrigation of golf courses surrounded by dwellings, it was decided that a tertiary treatment plant would be designed to meet California's wastewater reclamation requirements. The current treatment plant was constructed in three phases. California has very strict standards for effluent reuse and they are described in Title 22 of the California Code of Regulations. Use of reclaimed wastewater for most golf courses requires oxidation, coagulation, filtration and disinfection. The effluent has to meet a 2 NTU turbidity and 2.2 MPN/100 coliform standard. To comply with these standards, the District developed a unique treatment process that has allowed the District to be in full compliance since start-up without a single violation of the plant's discharge requirements. The initial treatment process consists of oxidation ponds. Mechanical aerators are located on the ponds to ensure that sufficient oxygen is provided at all times for treatment and most importantly for odor control. The pond effluent is discharged into two large reservoirs. These two reservoirs are sized to store wastewater for up to 150 days during periods of non-irrigation. When irrigation can be performed on the golf course, the tertiary treatment process is activated. It consists of dissolved air flotation for algae removal, filtration for polishing, and disinfection. Treatment design parameters, effluent quality results and capital and operating costs are presented.
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Bear, Laura. "Making a river of gold". Focaal 2011, n. 61 (1 dicembre 2011): 46–60. http://dx.doi.org/10.3167/fcl.2011.610104.
Testo completoAbstract (sommario):
This article examines the forms of state planning associated with neoliberalism, through a history and ethnography of the Kolkata Port Trust during liberalization. All state plans are promised futures which create a contested dialogue between bureaucrats and citizens. Neoliberal governance makes these interactions particularly ambiguous and opaque, because it relies on decentralized, speculative planning and the stimulation of public-private partnerships. These produce diverse, behind-the-scenes negotiations whose outcome is entirely different from the schemes initially outlined in textual state promises. It also places low-level bureaucrats in a liminal, Janus-faced role, in which they act both to create and to cross a boundary between public and private action. This new mode of rule is particularly problematic in settings such as the Hooghly River, where informality dominates in labor relationships. Bureaucrats deploy practices previously associated with “corruption” and patronage in order to enfold networks of unprotected labor into the revenue streams and plans of the state.
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Ronoko, Stephen R., Denny B. A. Karwur e Markus T. Lasut. "Mercury (Hg) contamination in Manado Bay, North Sulawesi, Indonesia". AQUATIC SCIENCE & MANAGEMENT 7, n. 1 (21 settembre 2019): 1. http://dx.doi.org/10.35800/jasm.7.1.2019.24993.
Testo completoAbstract (sommario):
Title (Bahasa Indonesia):Kontaminasi merkuri (Hg) di Teluk Manado, Sulawesi Utara, IndonesiaArtisanal gold minings, which are situated in the highlands of the northern part of Sulawesi Island,use mercury (Hg) to extract gold and dischargetheirs tailings into rivers; one of the rivers(Bailang River) is connected to Manado Bay. This could cause Hg contamination into the bay. This study aimed to assess the contamination of Hg in the aquatic ecosystem of the bay. For the assessment, the bay was divided into 2 parts, namely the North and the South, and the contamination was assessed by measuring the total Hg concentration in sediments and fishes. Determination of Hg concentration refers to the Indonesian National Standard (SNI) 01-2896-1992 and Guidance of Balai Riset dan Standarisasi Industri Manado. The results showed that the range of Hg concentrations in fish varied by species; in the northern part of the bay: Holocentridae (0.1144-0.1151 ppm), Siganidae (0.0020-0.0034 ppm), Apogonidae (0.0461-0.050 ppm), and Nemipterus (0.0142-0.0144 ppm ). While in the southern part of the bay: Holocentridae (0.1090-0.1104 ppm), Siganidae (0.160-0.164 ppm), Apogonidae (0.1280-0.1291 ppm), Nemipterus (0.0522-0.0530 ppm) , and Priacanthus sp. (0.0194-0.0210 ppm). The average concentration of Hg in sediments of the bay around river mouths varied based on location, i.e. Bailang River was 0.0502 ppm, Sario River was 0.0270 ppm, Bahu River was 0.0615 ppm, and Malalayang River was 0.0143 ppm.Pertambangan emas rakyat menggunakan merkuri (Hg), yang berada di daerah dataran tinggi bagian Utara Pulau Sulawesi, membuang limbah tailing ke sungai menuju ke laut; satu dari sungai tersebut (Sungai Bailang) bermuara ke Teluk Manado. Hal ini dapat menyebabkan kontaminasi Hg ke lingkungan perairan teluk. Penelitian ini bertujuan untuk menilai kontaminasi Hg di ekosistem perairan teluk tersebut. Untuk penilaian, perairan teluk dibagi 2 bagian, yaitu bagian Utara dan Selatan, dan kontaminasi dinilai dengan cara mengukur konsentrasi Hg total pada sedimen dan ikan. Penentuan konsentrasi Hg mengacu Standar Nasional Indonesia (SNI) 01-2896-1992 dan Panduan Balai Riset dan Standarisasi Industri Manado. Hasil penelitian menunjukkan, bahwa kisaran konsentrasi Hg dalam ikan bervariasi berdasarkan jenis; dibagian Utara teluk: Holocentridae(0,1144-0,1151 ppm), Siganidae (0,0020-0,0034 ppm), Apogonidae (0,0461-0,050 ppm), dan Nemipterus (0,0142-0,0144 ppm).Sedangkandi perairan bagian Selatan teluk: Holocentridae (0,1090-0,1104 ppm), Siganidae (0,160-0,164 ppm), Apogonidae (0,1280-0,1291 ppm), Nemipterus (0,0522-0,0530 ppm),dan Priacanthus sp.(0,0194-0,0210 ppm). Konsentrasi rata-rata Hg di sedimen perairan teluk sekitar muara Sungai Bailang sebesar 0,0502 ppm, muara Sungai Sario sebesar 0,0270 ppm, muara Sungai Bahu sebesar 0,0615 ppm, dan muara Sungai Malalayang sebesar 0,0143 ppm.
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Samokhvalov, Vladimir L., e Nikolay V. Ukhov. "Thermal regime of water courses of different order in the basin of the Upper Kolyma River". Arctic Environmental Research 18, n. 4 (31 dicembre 2018): 175–81. http://dx.doi.org/10.3897/issn2541-8416.2018.18.4.175.
Testo completoAbstract (sommario):
Evaluation of hydrological parameters and temperature regime of watercourses of various orders comes to the fore when studying the scientific problems of hydrobiology of watercourses and solving practical problems of development of fisheries and gold exploration in the regions of the Far North. This became particularly relevant due to a significant reduction in hydrological observations since the early 1990s. This article presents a quantitative investigation into the thermal regime of water courses and their spatial pattern. The paper focuses specifically studying the temperature and basic spatial parameters of streams and rivers in the area of interest. Statistical methods helped identify a close linkage between the temperature of water courses in the basin of the Upper Kolyma River and their respective sizes. A common trend has been found proving that the water temperature in the rivers increases downstream and with the increase in water course size, also known as order. A close correlation between the average water temperature, on the one hand, and the catchment area and water course length, on the other, is indicated by the relatively high correlation coefficients of 0.61 to 0.63 and 0.71 to 0.73, respectively. Average water temperatures in the summer and warm periods have been found to escalate with the increase of water course order from low (I and II) to high (VI–VII) by 4.7°C and 5.9°C, respectively, and in the Kolyma River – in the direction from the upper section (Orotuk village) to the lower section (the Korkodon River mouth) by 1.7°C and 2.1°C, respectively, even though the lower section of the river is located almost 2° north of the upper section. Due to the presence of perennial permafrost, river taliks have a cooling effect on the thermal regime of watercourses, so coolness occurs in sections of the river where there are favorable conditions for their formation. This is, first of all, the increased thickness of the well-permeable coarse-grained alluvium of the channel facies and open fracture zones in the bedrock.
22
Ryan, James J., Nathan Hayward e Lionel E. Jackson. "Landscape antiquity and Cenozoic drainage development of southern Yukon, through restoration modeling of the Tintina Fault". Canadian Journal of Earth Sciences 54, n. 10 (ottobre 2017): 1085–100. http://dx.doi.org/10.1139/cjes-2017-0053.
Testo completoAbstract (sommario):
The impact of Tintina Fault displacement on the development of the Yukon River and drainage basins of central Yukon is investigated through geophysical and hydrological modeling of digital terrain model data. Regional geological evidence suggests that the age of the planation of the Klondike Plateau is at least Late Cretaceous, rather than Neogene as previously assumed, and that surprisingly there has been little net incision in the region since the late Mesozoic. The Tintina Fault has been previously interpreted to have experienced ∼430 km of dextral displacement, primarily during the Eocene. However, the alignment of river channels across the fault at specific displacements, coupled with recent seismic events and related fault activity, suggests that the fault may have moved in stages over a longer time span. Topographic restoration and hydrological models show that the drainage of the Yukon River northwestward into Alaska via the ancestral Kwikhpak River was only possible at restored displacements of up to ∼50–55 km on the Tintina Fault. We interpret the published drainage reversals convincingly attributed to the effects of Pliocene glaciation as an overprint on earlier Yukon River reversals attributed to tectonic displacements along the Tintina Fault. At restored displacements between 230 and 430 km, our models illustrate that paleo-Yukon River drainage may have flowed eastward into the continental interior via an ancestral Liard River. The revised drainage evolution has wide-reaching implications for surficial geology deposits, the flow direction and channel geometries of the region’s ancient rivers, and importantly, for exploration of placer gold deposits.
23
Gerson, Jacqueline R., Simon N. Topp, Claudia M. Vega, John R. Gardner, Xiao Yang, Luis E. Fernandez, Emily S. Bernhardt e Tamlin M. Pavelsky. "Artificial lake expansion amplifies mercury pollution from gold mining". Science Advances 6, n. 48 (novembre 2020): eabd4953. http://dx.doi.org/10.1126/sciadv.abd4953.
Testo completoAbstract (sommario):
Artisanal and small-scale gold mining (ASGM) is the largest global source of anthropogenic mercury emissions. However, little is known about how effectively mercury released from ASGM is converted into the bioavailable form of methylmercury in ASGM-altered landscapes. Through examination of ASGM-impacted river basins in Peru, we show that lake area in heavily mined watersheds has increased by 670% between 1985 and 2018 and that lakes in this area convert mercury into methylmercury at net rates five to seven times greater than rivers. These results suggest that synergistic increases in lake area and mercury loading associated with ASGM are substantially increasing exposure risk for people and wildlife. Similarly, marked increases in lake area in other ASGM hot spots suggest that “hydroscape” (hydrological landscape) alteration is an important and previously unrecognized component of mercury risk from ASGM.
24
Derevska, K., O. Aleksandrov, V. Berehovenko, M. Kovalchuk, K. Rudenko, G. Silchenko e R. Spytsia. "PROSPECTS OF THE DNIESTER RIVER FLOODPLAIN TERRACES STRATA FOR GOLD MINERALIZATION". Visnyk of Taras Shevchenko National University of Kyiv. Geology, n. 3 (90) (2020): 71–77. http://dx.doi.org/10.17721/1728-2713.90.10.
Testo completoAbstract (sommario):
The article clarifies the stratigraphic binding and origin of silicon nodules, which served as the main raw material for the manufacture of tools for mammoth hunters of the Mezhyrich Late Paleolithic site. In archaeological publications, these nodules are often mentioned to be confined to the "Vyrzhikovsky layer" (the Albian layer of the Lower Cretaceous), which was formed under continental conditions and consists of sand-clay (kaolin, in particular) deposits. The analysis of the necessary conditions and possible mechanisms for the formation of silicon nodules indicates the erroneousness of such ideas. Most likely, the source of silicon raw materials was the marine deposits of the Cenomanian (Upper Cretaceous), or, in accordance with the modern stratigraphic division of the Mesozoic-Cenozoic sequence, deposits of the Burim suite (upper Albian – lower Cenomanian). The paleogeographic setting, sedimentological conditions and lithological composition of the "Vyrzhikovsky layer" did not ensure the formation of silicon nodules in it in the form of inclusions. The latter are diagenetic in origin and could only form in the thickness of carbonate rocks, free of clay minerals. The region of Kaniv dislocations was the optimal region from the silicon production point of view, which was determined: firstly, by the tectonic dislocation of the sedimentary sequence, which contributed to the removal of deposits containing silicon nodules in the thickness of younger rocks; secondly,the erosion activity of temporary streams, which brought these deposits to the level of the denudation cut-off. The most convenient place for collecting flints was not the outcrop of bedrock in ravines but the cones of their removal, which overlook the floodplains of the Dnipro and Ros'. The possibility of collecting flint in the immediate vicinity of the Mezhirich site, in the ravines and gullies between the Ros and Rosava rivers, does not find confirmation, since the chalk deposits here lie much lower than the local erosion base and are not exposed by ravines. Therefore, the leading role in the formation of the raw material supply of the Late Paleolithic site of Mezhirich was played by the region adjacent to the Kaniv mountains of the alluvial-proluvial plain.Despite long-term geological study of the Dniester River basin, we still have no clear evidences about gold-bearing potentiality of this area as well as origin of gold. The leading role of geological, geochemical and mineralogical criteria is proved for defining the prospects of substantial gold deposits finding within the Dniester river basin. Gold was found here in the crystalline basement and in the sedimentary cover rocks. Study of mineralogy and lithology of the terraces above the flood-plain and typomorphic peculiarities of native gold shows that palaeogeographic conditions and alimentation zones of debris vary at the different tectonic stages of this area development. Gold-bearing potential of the Pliocene-Quaternary sediments in the Dniester River basin is related to the Pliocene (VI-IX terraces above the flood-plain) and Quaternary (I-V terraces above the flood-plain) terraces complex of the Dniester river, as well as this river and its inflows recent alluvia. Our study of the Mid-flow part of the Dniester river basin allow to conclude that native gold was found in geologocal strata of all ages, from Proterozoic up to the recent alluvium. This fact points the necessity of further prospecting to find the mother lodes of gold. Our field study, samples analyses made as well as publications observation allow highlighting the principal directions of further prospecting and evaluation works. The main among that are: 1) comprehensive study of river Dniester alluvia and its terraces complex (previously VI–VII terraces), that will allow to specify their material composition, to assess real gold-bearing potential and to define the history of denudation areas changes; 2) lithogeochemical prospecting of primary and secondary dispersion haloes to clear the principal gold-bearing regularities; 3) definition of prospect plots within the area described; 4) modern analytical approach study of typomorphic peculiarities of native gold from alluvia and terrace deposits to define its ore formational affinity and mineral type.
25
Miranda, Omar, Mario Liotta, Alfredo Olguin e Alejandro Degiorgis. "El Consumo Hídrico de la agricultura y la minería aurífera en la cuenca del Río Jáchal, Provincia de San Juan, Argentina". Aqua-LAC 2, n. 1 (31 marzo 2010): 68–77. http://dx.doi.org/10.29104/phi-aqualac/2010-v2-1-07.
Testo completoAbstract (sommario):
En este trabajo se cuantificó el impacto de la minería aurífera en la disponibilidad de agua para riego en el valle de Jáchal, provincia de San Juan, Argentina. A partir del consumo hídrico de dos concesiones mineras sobre la cuenca del río Jáchal, Veladero (en explotación) y Lama (en etapa de estudio de impacto ambiental), se calculó el uso consuntivo de agua y el efecto regulador del embalse Cuesta del Viento. Suponiendo que los dos yacimientos mineros extraigan el volumen de agua máximo necesario para su funcionamiento en forma constante durante todo el año, se verificará una disminución de 4.47% en el caudal del río Jáchal, equivalente al agua que habría que entregar para regar una superficie de 728 ha de cultivos según el patrón actual de uso de suelo agrícola. Teniendo en cuenta el área en producción agrícola, la capacidad de distribución de la red de riego y la oferta hídrica promedio del río Jáchal, esto no generará déficit hídrico en los cultivos. Si bien en un año con bajas precipitaciones en cabecera de cuenca se puede contar con la reserva del dique Cuesta del Viento, en casos en los que el ciclo hidrológico seco se extendiese por más de cuatro años se debería tener en cuenta medidas para asegurar la provisión de agua para los cultivos de Jáchal.
26
Barkov, Andrei Y., Gennadiy I. Shvedov, Andrey A. Nikiforov e Robert F. Martin. "Platinum-group minerals from Seyba, Eastern Sayans, Russia, and substitutions in the PGE-rich pentlandite and ferhodsite series". Mineralogical Magazine 83, n. 4 (12 aprile 2019): 531–38. http://dx.doi.org/10.1180/mgm.2019.16.
Testo completoAbstract (sommario):
AbstractChromitite zones associated with ultramafic units of the Lysanskiy layered complex of dunite–peridotite–gabbro composition could well represent the primary source for the placers bearing platinum-group minerals (PGM) of the entire drainage of the River Sisim and its tributaries, the rivers Ko and Seyba, eastern Sayans. Alluvial gold present in the placers of River Seyba, as elsewhere in the Sisim Placer Zone, reflects mineralisation during a recent period of tectonic activity. We focus on the PGM in the Seyba suite, and in particular on the attributes of pentlandite enriched in platinum-group-elements (PGE) and the compositionally similar and recently defined ferhodsite, which were trapped in host grains of Os–Ir–Ru alloy. Both minerals formed from small volumes of fractionated Fe–Ni–Cu melt considerably enriched in the PGE. In the Seyba suite, as in several others, the amounts of PGE in ferhodsite exceeds that in pentlandite, which results in a greater proportion of vacancies than in pentlandite.
27
Hofmann, J., M. Venohr, H. Behrendt e D. Opitz. "Integrated water resources management in central Asia: nutrient and heavy metal emissions and their relevance for the Kharaa River Basin, Mongolia". Water Science and Technology 62, n. 2 (1 luglio 2010): 353–63. http://dx.doi.org/10.2166/wst.2010.262.
Testo completoAbstract (sommario):
Within the framework of Integrated Water Resources Management (IWRM) the nutrient and heavy metal levels within the Kharaa river basin were investigated. By the application of the MONERIS model, which quantifies nutrient emissions into river basins, various point and diffuse pathways, as well as nutrient load in rivers, could be analysed. Despite seasonal variations and inputs of point sources (e.g. Wastewater Treatment Plant Darkhan) the nutrient concentrations in most of the subbasins are on a moderate level. This shows evidence for a nutrient limited ecosystem as well as dilution effects. However, in the middle and lower reaches heavy metal concentrations of arsenic and mercury, which are linked to mining activities in many cases, are a point of concern. Thus measures are necessary to protect the valuable chemical and ecological status of the Kharaa River and its tributaries. As a result of the growing economic pressure Mongolia will enhance the agricultural production by irrigation. Until 2015 about 60% of the agricultural land shall be irrigated. In addition the gold mining activities shall increase by 20% a year. Both sectors have a high demand for water quantity and quality. The model MONERIS allows the assessment of measures which are inevitable to protect the water quality under shrinking water availability.
28
Sari, Mega M., Takanobu Inoue, Yoshitaka Matsumoto e Kuriko Yokota. "Measuring total mercury due to small-scale gold mining activities to determine community vulnerability in Cihonje, Central Java, Indonesia". Water Science and Technology 73, n. 2 (5 ottobre 2015): 437–44. http://dx.doi.org/10.2166/wst.2015.503.
Testo completoAbstract (sommario):
This research is comparative study of gold mining and non-gold mining areas, using four community vulnerability indicators. Vulnerability indicators are exposure degree, contamination rate, chronic, and acute toxicity. Each indicator used different samples, such as wastewater from gold mining process, river water from Tajum river, human hair samples, and health questionnaire. This research used cold vapor atomic absorption spectrometry to determine total mercury concentration. The result showed that concentration of total mercury was 2,420 times than the maximum content of mercury permitted in wastewater based on the Indonesian regulation. Moreover, the mercury concentration in river water reached 685 ng/l, exceeding the quality threshold standards of the World Health Organization (WHO). The mercury concentration in hair samples obtained from the people living in the research location was considered to identify the health quality level of the people or as a chronic toxicity indicator. The highest mercury concentration – i.e. 17 ng/mg, was found in the gold mining respondents. Therefore, based on the total mercury concentration in the four indicators, the community in the gold mining area were more vulnerable to mercury than communities in non-gold mining areas. It was concluded that the community in gold mining area was more vulnerable to mercury contamination than the community in non-gold mining area.
29
Martín, Alison, Juliana Arias, Jennifer López, Lorena Santos, Camilo Venegas, Marcela Duarte, Andrés Ortíz-Ardila, Nubia de Parra, Claudia Campos e Crispín Celis Zambrano. "Evaluation of the Effect of Gold Mining on the Water Quality in Monterrey, Bolívar (Colombia)". Water 12, n. 9 (10 settembre 2020): 2523. http://dx.doi.org/10.3390/w12092523.
Testo completoAbstract (sommario):
Gold mining uses chemicals that are discharged into rivers without any control when there are no good mining practices, generating environmental and public health problems, especially for downstream inhabitants who use the water for consumption, as is the case in Monterrey township, where the Boque River water is consumed. In this study, we evaluate Boque River water quality analyzing some physicochemical parameters such as pH, heavy metals, Hg, and cyanide; bioassays (Lactuca sativa, Hydra attenuata, and Daphnia magna), mutagenicity (Ames test), and microbiological assays. The results show that some physicochemical parameters exceed permitted concentrations (Hg, Cd, and cyanide). D. magna showed sensitivity and L. sativa showed inhibition and excessive growth in the analyzed water. Mutagenic values were obtained for all of the sample stations. The presence of bacteria and somatic coliphages in the water show a health risk to inhabitants. In conclusion, the presence of Cd, Hg, and cyanide in the waters for domestic consumption was evidenced in concentrations that can affect the environment and the health of the Monterrey inhabitants. The mutagenic index indicates the possibility of mutations in the population that consumes this type of water. Bioassays stand out as an alert system when concentrations of chemical contaminants cannot be analytically detected.
30
Baturin, G. N., e V. V. Gordeev. "Geochemistry of suspended matter in the Amazon river waters". Геохимия 64, n. 2 (15 marzo 2019): 195–205. http://dx.doi.org/10.31857/s0016-7525642195-205.
Testo completoAbstract (sommario):
The duplicate samples of the Amazon River suspended matter (SM) collected during Cruise 9th of R/V Professor Shtokman were studied using modern analytical techniques. Waters of the Amazon basin are subdivided into three main types differing in SM content and chemical composition: white (turbid yellow waters of the Amazon River and Madeira tributary), clear (transparent waters of the large Xingu, Tapajós, Trombetas, and Tocantins tributaries) and black (waters with strong coffer color, high content of dissolved organics, and elevated acidity, Riu Negro). The specific features of SM from different parts of the river basin have been established. The contents and relationships of major and trace elements in SM vary within wide ranges, but in general the bulk composition of SM is close to the average composition of river SM and clay rocks, except for some samples from clear waters. The SM of the white and clear waters (blackwater samples unfortunately have not been preserved) are variably enriched in Hg. Literature data indicate that artisanal gold mining with the use of Hg (amalgamation method) has been carried out for many years in the Amazon Basin, i.e., SM enrichment in Hg is related to the anthropogenic factor. At the same time, significant (up to two orders of magnitude) enrichment of SM of the clear water Xingu and Tokantins rivers, the Amazon tributaries, in Sn, Zn, Pb, and to lesser extent, in Cu, Cd, Ag, and some other metals give grounds to suggest ore mineralization in these regions.
31
Tsyrenova, Marina, Evgenia Pyzhikova e Elena Vasilyeva. "Anthropogenic Vegetation in the River Valley Amalat". BIO Web of Conferences 16 (2019): 00049. http://dx.doi.org/10.1051/bioconf/20191600049.
Testo completoAbstract (sommario):
The article presents the results of a research study of anthropogenic affects of gold mining on forest landscapes in Northern Transbaikalia, Russia and processes of natural reclamation of vegetation cover of the disturbed areas. The study area is located northwest of the Maliy Amalat River, which flows along the Vitim Plateau; in the floodplains of its two tributaries the Aunik River and the Bagdarin River. It is an area where a large number of alluvial gold deposits have been discovered. Some of these deposits are currently being developed, some have already been explored, and some have been abandoned. The authors consider the current state of vegetation cover in a key area of the Amalat River basin, near villages of Malovsky and Bagdarin. The problem of natural resources development and conservation is becoming extremely important for the area under study because open-pit gold mining methods that are used here drastically change the environment and affect water, land and forest resources.
32
T, Azzaya, Burmaa G, S. Alen, Narangarav T e Nyamdelger Sh. "Arsenic occurrence in water bodies in Kharaa river basin". Mongolian Journal of Chemistry 18, n. 44 (13 febbraio 2018): 12–19. http://dx.doi.org/10.5564/mjc.v18i44.932.
Testo completoAbstract (sommario):
Distribution of arsenic (As) and its compound and related toxicology are serious concerns nowadays. Gold mining activity is one of the anthropogenic sources of environmental contamination regarding As and other heavy metals. In Mongolia, the most productive gold mining sites are placed in the Kharaa river basin. A hundred water samples were collected from river, spring and deep wells in this river basin. Along with total As and its species-As(III) and As(V), examination of concentration levels of other key parameters, 21 heavy metals with pH, total hardness, electric conductivity, anion and cations, was also carried out. In respect to the permissible limit formulated by the Mongolian National Drinking water quality standard (MNS 0900:2005, As10 µg/l), the present study showed that most of samples were found no contamination. In Kharaa river basin, an average concentration of total As in surface water was 4.04 µg/l with wide range in 0.07−30.30 µg/l whereas it was 2.24 µg/l in groundwater. As analysis in surface water in licensed area of Gatsuurt gold mining showed a mean concentration with 24.90 µg/l presenting higher value than that of value in river basin by 6 orders of magnitude and it was 2 times higher than permissible level as well. In Boroo river nearby Boroo gold mining area, As concentration in water was ranged in 6.05−6.25 µg/l. Ammonia pollution may have present at estuary of Zuunmod river in Mandal sum with above the permissible level described in national water quality standard. Geological formation of the rocks and minerals affected to change of heavy metal concentration, especially As and uranium (U) at spring water nearby Gatsuurt-Boroo improved road.
33
Rahma Yulis, Putri Ade. "PENENTUAN KADAR LOGAM TIMBAL (Pb) AIR SUNGAI SINGINGI DI KABUPATEN KUANTAN SINGINGI RIAU". Journal of Research and Education Chemistry 1, n. 2 (29 luglio 2019): 30. http://dx.doi.org/10.25299/jrec.2019.vol1(2).3502.
Testo completoAbstract (sommario):
Heavy metal is the most hazardous of contaminats group. Our ecosystem has been contaminated by high concentrated of heavy metal that was generated from human activities such as industrial. On this research heavy metal content due to illegal gold mining (PETI) activities in Singingi river, Riau was measured. This was held because the river has degradation of its quality immediately. It was marked by high turbidity and declining of organism in that river. The choice of determining the content of heavy metal Pb or lead because we know that gold processing is not only used by mercury but also used by lead and cadmium to bind gold. The three metals are used to bind the gold and separate it from soil and stone in from sulfide.. This research used survey method with purposive sampling based on the rise location of PETI activities. Sample was measured at 4 point that started from the nearest and up to the furthest of PETI activities. The result of lead measurement was 0, 00382 mg/L; 0,00165 mg/L; 0,00124 mg/L and 0,02525 mg/L, respectively. The results obtained indicate that the river has been contaminated with lead metal although if were compared with the quality standard of heavy metal in aquatic Lead still allowed with the number of quality standard for lead is 0,03 mg/L.
Keywords : PETI activities, heavy metal measurement, Lead (Pb) Singingi river
34
Ukraintsev, V. Yu, e I. S. Voskresenskiy. "Structure and Late Cenozoic Development of Valleys at the Severnye Uvaly Upland". Вестник Пермского университета. Геология 19, n. 4 (2020): 303–16. http://dx.doi.org/10.17072/psu.geol.19.4.303.
Testo completoAbstract (sommario):
Using public materials (articles, open-file reports of geological survey at the Severnye Uvaly, and digital elevation models), we studied river valleys of the Severnye Uvaly Upland and established specific types of gold placer-like occurrences and interconnection between river valley structure and placer location. We distinguished 4 cycles of erosion in Late Cenozoic at the Severnye Uvaly. For placer forming, the one of the most important features is a spatial coincidence of valleys in every cycle of erosion. An analysis of the longitudinal and transverse profiles of the valleys according to the DSM allows evaluating the content of the gold and its location in the river valley.
35
Alam, Muhammad, Javed Akhter Qureshi, Garee Khan, Manzoor Ali, Irfan Ali e Naeem Abbas. "The Efficiency of Amalgamation and Cyanidation for the Extraction of Placer Gold Deposits of Indus River Basin along Gilgit to Thalachi (Gilgit-Baltistan)". International Journal of Economic and Environmental Geology 10, n. 2 (4 settembre 2019): 134–38. http://dx.doi.org/10.46660/ijeeg.vol10.iss2.2019.274.
Testo completoAbstract (sommario):
Separation of gold from placers are not given importance in Pakistan, but in the economy of Gilgit-Baltistan,it plays a vital role. The study mainly focused on shaking table technique for the extraction of gold from placer depositsalong Gilgit river between Gilgit and Thalachi, near Gilgit and Astore river junction. For the separation of gold, fromthe concentration of shaking table the Hg; mercury amalgamation has been used for it. In the result of theamalgamation process recovered gold was 27.12%. The cyanidation process was used to separate from remains ofmercury amalgamation, tailing and middling of shaking table. The graphical results of gold extraction with bottle rollcyanidation and agitation method were compared. The results of gold separation using bottle roll cyanidation andagitation methods were about 87.5% and 29.8% respectively. It is clear from the results, the bottle roll cyanidation is abetter technique for the separation of fine gold from placers along with downstream waterway areas, where placerdeposits occur.
36
Alam, Muhammad, Javed Akhter Qureshi, Garee Khan, Manzoor Ali, Irfan Ali e Naeem Abbas. "The Efficiency of Amalgamation and Cyanidation for the Extraction of Placer Gold Deposits of Indus River Basin along Gilgit to Thalachi (Gilgit-Baltistan)". International Journal of Economic and Environmental Geology 10, n. 2 (4 settembre 2019): 134–38. http://dx.doi.org/10.46660/ojs.v10i2.274.
Testo completoAbstract (sommario):
Separation of gold from placers are not given importance in Pakistan, but in the economy of Gilgit-Baltistan,it plays a vital role. The study mainly focused on shaking table technique for the extraction of gold from placer depositsalong Gilgit river between Gilgit and Thalachi, near Gilgit and Astore river junction. For the separation of gold, fromthe concentration of shaking table the Hg; mercury amalgamation has been used for it. In the result of theamalgamation process recovered gold was 27.12%. The cyanidation process was used to separate from remains ofmercury amalgamation, tailing and middling of shaking table. The graphical results of gold extraction with bottle rollcyanidation and agitation method were compared. The results of gold separation using bottle roll cyanidation andagitation methods were about 87.5% and 29.8% respectively. It is clear from the results, the bottle roll cyanidation is abetter technique for the separation of fine gold from placers along with downstream waterway areas, where placerdeposits occur.
37
Stepanov, V. A. "Reference couple gold deposit — placer as a basis for forecasting of the new gold deposits in Amur river basin". Proceedings of higher educational establishments. Geology and Exploration, n. 6 (3 gennaio 2019): 49–58. http://dx.doi.org/10.32454/0016-7762-2018-6-49-58.
Testo completoAbstract (sommario):
About 1400 placers and several dozens of ore gold deposits are known in the Amur gold-bearing province. Placers are to a large degree worked out, so the future of the province is seen to be in the discovery of the new gold deposits. The paper shows the dependence of the productivity and composition of the native gold placers on the size and formational affiliation of the placer-forming gold deposit. The reference couples have been identified: the gold deposit and the placer formed due to the erosion of its' upper part. For example, the Tokur gold-quartz deposit is a channel-fill placer in Tokur stream, gold-sulphide-quartz deposit Pioneer—the placer in Ulungi river, gold-sulphide-quartz deposit Bamskoe—the placer of Chulbangro river, Berezitovoye gold-polymetallic deposit—placer of the Konstantinovsky stream and gold-silver field Pokrovskoye—placer of Sergeevsky stream. A forecast of new gold deposits of a certain formation has been made according to the parameters of the placer and the composition of the native gold. A similar selection of reference couples of a gold deposit and a placer with the subsequent forecasting of new deposits can be one of the methods for predicting gold deposits in the other gold-bearing provinces.
38
Aguilar Pesantes, Alby, Elizabeth Peña Carpio, Tomas Vitvar, Manuel María Mahamud López e Juan Menéndez-Aguado. "A Multi-Index Analysis Approach to Heavy Metal Pollution Assessment in River Sediments in the Ponce Enríquez Area, Ecuador". Water 11, n. 3 (21 marzo 2019): 590. http://dx.doi.org/10.3390/w11030590.
Testo completoAbstract (sommario):
The area of Ponce Enríquez, Southern Ecuador, is one of the most important artisanal and small scale gold mining (ASGM) areas in the country, where informal mining operations can be found using amalgamation technique, even though it has been prohibited since 2010. Considering the potential impact of these mining operations, the present research focused on heavy metal pollutants in subsurface sediments at 214 sampling locations from several detailed sampling campaigns in the rivers Fermín, Fermín Norte, Guanache, Villa, and Siete. Four parameters were calculated to evaluate the geochemical composition of the river sediment and heavy metal concentrations: The enrichment factor (EF), the geo-accumulation index (Igeo), the contamination factor (Cf) and the pollution load index (PLI). The analyzed elements were Cu, Pb, Zn, Ni, As, Cd, Sb, Sr, and Hg. Due to the lack of standards for pollution levels in sediments in Ecuador, Canadian guidelines were used as interim sediment quality guidelines (ISQG) in this research for comparison with the obtained results in subsurface sediments. The multi-index geochemical analysis indicated elevated heavy metal concentrations in all subsurface sediments in the studied river ecosystems.
39
Alam, Muhammad, Javed Akhter Qureshi, Garee Khan, Manzoor Ali, Naeem Abbas, Sher Sultan, Asghar Khan e Yasmeen Bano. "The Process Designing of Gold Extraction from Placers of Passu to Shimshal (Hunza Valley) Gilgit-Baltistan by Mercury Amalgamation and Cyanidation Leached Method". International Journal of Economic and Environmental Geology 10, n. 4 (19 febbraio 2020): 25–29. http://dx.doi.org/10.46660/ijeeg.vol10.iss4.2019.348.
Testo completoAbstract (sommario):
Gold wash through panning or washing in the fluvial sediments or sands is done on the river banks inSkardu, Hunza and other places. The method of gold washing is very crude, primitive and most of the gold is washedaway back into the river. The current study mainly focused on extraction of placer gold deposits. Pneumatic machinesfrom Passu to Shimshal (Hunza valley) Gilgit-Baltistan. The mercury amalgamation and cyanide leached methods havebeen used for placer gold deposits extraction from the concentrate obtained from shaking table. The amount of goldrecovered from amalgamation method with mercury was 30.9%. The alloyed gold with other metals, gold dust, and finegold was recovered by chemical process. The reagent consumption, i.e. 1.4 kg/ton of NACN and 6 Kg / ton of CaOwere used for extraction of placer gold deposits. The extracted gold is 10.24 g /t and silver 22 g /t and the remaininggold like the amalgamation residue, tailings and middlings are extracted by cyanidation leached method. The extractionof gold by cyanidation process was compared graphically, and study results revealed that extraction of gold usingcyanidation leached method was 91.40% and silver 100%, respectively.
40
Alam, Muhammad, Javed Akhter Qureshi, Garee Khan, Manzoor Ali, Naeem Abbas, Sher Sultan, Asghar Khan e Yasmeen Bano. "The Process Designing of Gold Extraction from Placers of Passu to Shimshal (Hunza Valley) Gilgit-Baltistan by Mercury Amalgamation and Cyanidation Leached Method". International Journal of Economic and Environmental Geology 10, n. 4 (19 febbraio 2020): 25–29. http://dx.doi.org/10.46660/ojs.v10i4.348.
Testo completoAbstract (sommario):
Gold wash through panning or washing in the fluvial sediments or sands is done on the river banks inSkardu, Hunza and other places. The method of gold washing is very crude, primitive and most of the gold is washedaway back into the river. The current study mainly focused on extraction of placer gold deposits. Pneumatic machinesfrom Passu to Shimshal (Hunza valley) Gilgit-Baltistan. The mercury amalgamation and cyanide leached methods havebeen used for placer gold deposits extraction from the concentrate obtained from shaking table. The amount of goldrecovered from amalgamation method with mercury was 30.9%. The alloyed gold with other metals, gold dust, and finegold was recovered by chemical process. The reagent consumption, i.e. 1.4 kg/ton of NACN and 6 Kg / ton of CaOwere used for extraction of placer gold deposits. The extracted gold is 10.24 g /t and silver 22 g /t and the remaininggold like the amalgamation residue, tailings and middlings are extracted by cyanidation leached method. The extractionof gold by cyanidation process was compared graphically, and study results revealed that extraction of gold usingcyanidation leached method was 91.40% and silver 100%, respectively.
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Meldrum, Barbara Howard. "River of Red Gold by Naida West". Western American Literature 34, n. 2 (1999): 254–55. http://dx.doi.org/10.1353/wal.1999.0092.
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Davis, Benita, Temitope D. Timothy Oyedotun e Denise A. Simmons. "An Examination of Selected Physiochemical Water Quality Parameters of the Rivers near Kaieteur National Park". Book of Abstracts: Student Research 1 (4 novembre 2020): 44. http://dx.doi.org/10.52377/sejm1908.
Testo completoAbstract (sommario):
Studies have indicated that gold mining operations increased within the vicinity of Kaieteur National Park, yet its impacts on freshwater systems could not have been assessed due to an absence of baseline data for water and sediment quality in the area. This study examined the total mercury and non-metallic physiochemical water quality parameters at four sampling sites: Echerak River, Muri-Muri River, Potaro River before Kaieteur Falls, and Potaro River after Kaieteur Falls.
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Dethier, Evan N., Shannon L. Sartain e David A. Lutz. "Heightened levels and seasonal inversion of riverine suspended sediment in a tropical biodiversity hot spot due to artisanal gold mining". Proceedings of the National Academy of Sciences 116, n. 48 (11 novembre 2019): 23936–41. http://dx.doi.org/10.1073/pnas.1907842116.
Testo completoAbstract (sommario):
In recent years, rising gold prices have exacerbated the global proliferation of artisanal-scale gold mining (ASGM), with catastrophic consequences for human and ecological health. Much of this burgeoning industry has occurred in biodiversity hot spots, notably in the tropical forests of South America. While the loss of tropical forests and floodplains as a result of ASGM has been well characterized, ASGM impacts on riverine hydrological properties are less understood. Previous fieldwork on ASGM-affected and gully-eroded tropical streams and rivers has demonstrated that increases in suspended-sediment concentration (SSC) can substantially impact fish diversity and aquatic community structure, yet our understanding of the timing and scope of impacts of such increases is limited by the lack of long-term records of SSC. To address this challenge, we present a 34-y analysis of the direct effect of ASGM on 32 river reaches in the Madre de Dios region of Peru, which has been heavily impacted by ASGM since the 1980s. We evaluate spatial and temporal patterns of impacts using estimated SSC derived from Landsat satellite imagery. We find that 16 of 18 stretches of river impacted by ASGM show significant increasing trends in SSC (P < 0.05), while only 5 of 14 unaffected sites do so. Additionally, ASGM appears to reverse natural seasonal cycles of SSC, which may imperil aquatic species. Overall, our findings indicate that ASGM is fundamentally altering optical water quality dynamics of a critical tropical biodiversity hot spot and provide guidance for future regulation of these activities.
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Rumbino, Yusuf, Fani Serangmo, Herry Zadrak Kotta, Woro Sundari, Ika Krisnasiwi e Noni Banunaek. "PEMBINAAN DAN PENDAMPINGAN KEPADA PENAMBANG EMAS TANPA IJIN DI DESA NOELTOKO, KEC.MIOMAFFO BARAT, KAB.TTU". Jurnal Pengabdian UntukMu NegeRI 3, n. 2 (1 novembre 2019): 216–22. http://dx.doi.org/10.37859/jpumri.v3i2.1549.
Testo completoAbstract (sommario):
Abstract
Exploitation of natural resources through unlicensed gold mining (PETI) is not in accordance with mining operational standards occurring along the Noeltoko River, West Miomaffo Subdistrict, Timor Tengah Utara Regency, East Nusa Tenggara Province resulting in damage and environmental degradation. Changes and environmental damage include the formation of dug holes around the river flow, turbidity of water, changes in river flow. Other problems that arise are conflicts between these PETI workers and with other communities. This community service activity aims to provide an understanding to the community about the importance of maintaining and caring for rivers from excavation in the river walls that can cause debris / landslides explaining the impact of the use of hazardous materials such as mercury / mercury and cyanide, socialization of regulations regarding the formation of People's Mining Areas (WPR) ), introducing "sluice box" equipment to help the process of separating gold sand from sand. This activity was supported by the UPT ESDM Atambua Branch and was followed by 40 people who used to mine on the Noeltoko river. It is expected that the guidance and assistance can raise public awareness to be able to mine but still preserve the environment
Keyword: PETI, Noeltoko, WPR, sluicebox,
Abstrak
Eksploitasi sumber daya alam melalui Penambangan Emas Tanpa Izin (PETI) tidak sesuai dengan standar operasional penambangan terjadi di sepanjang sungai Noeltoko-Kecamatan Miomaffo Barat, Kabupaten Timor Tengah Utara Propinsi Nusa Tenggara Timur yang mengakibatkan kerusakan dan penurunan kualitas lingkungan. Perubahan dan kerusakan lingkungan tersebut diantaranya terbentuk lubang-lubang galian di sekitar aliran sungai, kekeruhan air, berubahnya aliran sungai.. Permasalahan lain yang timbul adalah konflik antar pekerja PETI ini maupun dengan masyarakat lain. Kegiatan pengabdian kepada masyarakat ini bertujuan untuk memberikan pemahaman kepada masyarakat mengenai pentingnya menjaga dan merawat sungai dari penggalian di dinding sungai yang dapat mengakibatkan runtuhan/longsoran menjelaskan dampak penggunaan bahan berbahaya seperti air raksa/merkuri dan sianida, sosialisasi peraturan tentang pembentukan Wilayah Pertambangan Rakyat (WPR), mengenalkan peralatan “sluice box” untuk membantu proses pemisahan buiran emas dari pasir.Kegiatan ini didukung oleh pihak UPT ESDM Cabang Atambua dan dikuti oleh 40 orang masyarakat yang biasa menambang di sungai Noeltoko. Diharapkan dengan adanya pembinaan dan pendampingan dapat menimbulkan kesadaran masyarakat untuk dapat menambang namun tetap menjaga kelestarian lingkungan
Kata kunci: PETI, Noeltoko, WPR, sluicebox
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Genesa Hatika, Rindi, Indang Dewata, Alizar ., Purwo Subekti e Saiful Anwar. "Determination the Index of Radioactive Risk In The Batang Kuantan River". International Journal of Engineering & Technology 7, n. 2.13 (15 aprile 2018): 429. http://dx.doi.org/10.14419/ijet.v7i2.13.18133.
Testo completoAbstract (sommario):
NORM is a material containing radioactive elements that exist naturally. All minerals and raw materials contain radionuclides from nature, most important for radiation protection purposes are the U-238, Th-232 and K-40 decay series. This element naturally grows and is considered a major contributor to the annual individual background radiation dose. Therefore, each individual can be exposed to NORM through various activities they do, one of which is gold mining activities. Gold mining in addition to causing exposure to NORM, is believed also can cause significant environmental damage. This study aims to determine the index of radioactive risks that resulted from gold mining activities in the batang kuantan river. The sample used for this research is soil from batang kuantan river which then analyzed using gamma ray spectrometry. The results show that the index of radioactive risk value indicated by all soil samples in the batang kuantan river is still below the predetermined maximum limit value.
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RAPOSO, D., P. BELART, R. HABIB, F. FORTES e M. L. LORINI. "Benthic Foraminifera and Thecamoebians of Godineau River Estuary, Gulf of Paria, Trinidad Island". Anuário do Instituto de Geociências - UFRJ 40, n. 2 (26 maggio 2017): 118–43. http://dx.doi.org/10.11137/2017_02_118_143.
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RAPOSO, D., P. BELART, R. HABIB, F. FORTES e M. L. LORINI. "Benthic Foraminifera and Thecamoebians of Godineau River Estuary, Gulf of Paria, Trinidad Island". Anuário do Instituto de Geociências - UFRJ 40, n. 2 (26 maggio 2017): 118–43. http://dx.doi.org/10.11137/2017_2_118_143.
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Narváez López, Francisco. "Orígenes del topónimo Río de Oro". Aldaba, n. 40 (15 dicembre 2017): 129. http://dx.doi.org/10.5944/aldaba.40.2015.20569.
Testo completoAbstract (sommario):
Este trabajo realiza una aproximación a los orígenes del topónimo río de Oro a través del estudio de la cartografía histórica, libros de geografía, documentos oficiales, literatura, prensa escrita, etc. Igualmente se aborda el uso del topónimo Uad el Meduar y sus variantes en Marruecos. Ambos se refieren al mismo río, pero en un espacio distinto, es decir, a su paso por Marruecos y Melilla. Los dos hidrónimos tienen un origen diferente. El nombre de Uad el Meduar enumera o hace referencia a unas de las características físicas más relevante del río, es decir, a sus meandros. Por el contrario, el origen del nombre de río de Oro hay que buscarlo en las leyendas que hacían referencia a su riqueza aurífera, algo que nunca se ha demostrado y que ha pervivido entre nosotros hasta bien entrado el siglo XX, atrayendo a estos lugares a buscadores de oro y fortuna.This work is an approach to the origin of the place-name of the Gold River through the study of historical cartography, geography books, official documents, literature, press news and so on. At the same time, we deal with the use of the name Uad El Meduar and its variations in Morocco. Both of them refer to the same river but in a different place, that is, depending on if the river goes through Morocco or through Melilla. The two names have a different origin. The name of Uad el Meduar refers to some of the most relevant physical characteristics of the river, its meanders. On the contrary, the origin of the name Gold River” can be found in the legends that make reference to its gold wealth, something that has never been proved and that has been living with us until the end of the XX century, attracting to these places gold prospectors and fortune hunters.
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Tabita Tuny, Margaretha, e Kurnia Kurnia. "Analysis of Mercury Concentration on The Water and Sediment at Tiabo River, Roko, West Galela District, North Halmahera". Journal of Pure and Applied Chemistry Research 9, n. 1 (30 aprile 2020): 23–31. http://dx.doi.org/10.21776/ub.jpacr.2020.009.01.511.
Testo completoAbstract (sommario):
Gold mining activity at Tiabo river in the North Halmahera causes the water on the river is contaminated by mercury. The contamination mercury on the water can damage food chain and adverse consequences toward health of people, fish, and so on. The purpose of this study is to obtain the concentration of mercury contamination that was caused by gold mining activity. The water and sediment sample was obtained by purposive sampling. The characterization of concentration mercury in the water and sediment using mercury analyzer HG-300 in the wave length 253.72 nm. The result shows that mercury concentration of the water in the six and five sample point in the rainy session and the dry session respectively is <0.66 µg/L, and the mercury concentration in the sediment shows that the lower value in the upstream river was 1.2 mg/kg and the higher concentration in the middle of river was 8.94 mg/kg respectively in the rainy session. The result indicates that the contamination mercury in the moderate danger level according to the IADC/CEDA data standard.
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Raji, Iyioluwa Busuyi, Emile Hoffmann, Adeline Ngie e Frank Winde. "Assessing Uranium Pollution Levels in the Rietspruit River, Far West Rand Goldfield, South Africa". International Journal of Environmental Research and Public Health 18, n. 16 (11 agosto 2021): 8466. http://dx.doi.org/10.3390/ijerph18168466.
Testo completoAbstract (sommario):
The Rietspruit is located in Gauteng Province, South Africa, within the Witwatersrand Basin. The basin is noted for its vast gold deposit. The river extends for about 60 km before joining the Vaal River. The aim of this study was to determine the concentration of uranium in the Rietspruit and the factors that influenced the concentration of U at each of the sites. The source of uranium in the river is the discharge from the gold mine and the mine wastes. Inductively coupled plasma mass spectrometry was used for water and sediment analysis in order to determine the concentration of U. High concentration of U was found in the river water and sediment, which is above the permissible limit of U. The water is used for irrigation of farmlands, cattle watering and for human consumption despite the high concentration of uranium in it. Ingestion of uranium is dangerous to human health. Due to the toxic nature of uranium, consumption of the water for domestic use and agriculture purpose must be discouraged.