Alluvial Mining Research Articles

Применение тактильной сенсорной системы при сбойке встречных горных выработок

At present, the problem of advancing mine workings when connecting them is that after advancing, the workings often coincide within the project workings’ contours, which causes a significant increase of the costs, diminishes the safety and creates ecological issues. The instrumental methods cannot provide quality determination of the workings advance direction when connecting the workings, thus the work safety deteriorates, and the cost of eliminating the consequences of the non-quality connection increases. To improve the ways of connecting the workings, either the existing technology should be modified or a new technology is needed. The purpose of the study is to develop a new technology for determining the direction of the counter workings when connecting the workings. The technology involves a tactile sensory system of man and is realized by the comparison of the degree of the rock surface vibration effect on a human palm at different points of the face. The vibration is created by drilling a blast-hole, and it is measured by applying the palm to the face. The suggested technology can enhance the advance exactness and safety, as well as increase the mineral output and reduce the costs of advancing the counter mine workings due to the decrease in the deviation from the target direction when connecting the workings. The technology can be used when advancing counter mine workings and connecting the workings in ore and alluvial mines.

Environmental and social impacts identification for small-scale alluvial mining projects

PurposeThe purpose of the work is to use a systematic process to identify the environmental and social impacts of small-scale alluvial gold mining projects using data from Ghana.Design/methodology/approachIn this work, we used survey data collected from experts in the mining sector. This was followed by the use of a risk analysis approach to identify the significant and non-significant environmental and social impacts.FindingsSeven key impacts associated with typical alluvial mining operations were identified. The first two are the loss of vegetation and the issue of airborne diseases from dust as a result of vegetation losses during the clearing of vegetation in the block out area. The third and fourth issues were loss of vegetation and airborne diseases as a result of vegetation losses during the removal of overburden. The fifth, sixth and seventh, most significant issues identified were the pollution from smoke fumes from the processing machines; and wastewater from the washing process. The last issue of significance was the dust pollution from the transportation of the washed gravel back to the mined pit.Research limitations/implicationsOne main limitation is that the data for this study were collected from Ghana.Practical implicationsThe results indicate the need for proper and systematic measures to identify the environmental and social impacts of mining activities.Originality/valueThe work provides some insights into the strategies of identifying environmental and social impacts of mining activities. It is also one of the key works that systematically identify environmental and social impacts of small-scale alluvial gold projects.

Historical mercury losses from the gold mines of Victoria, Australia

Health and ecological risks associated with the use of mercury in gold mining are well known, with much recent attention focussed on contemporary small-scale artisanal mining. Legacy tailings from historical gold mining may also present ongoing risks, as the industry used large quantities of mercury with minimal environmental regulation to limit its discharge. This occurred in both alluvial (placer) mining and in processing auriferous ores. Analysis of historical data on mercury use in the mining industry in Victoria, Australia, indicates that at least 131 tonnes of elemental mercury were discharged into the environment as mine tailings between 1868–1888, with the total amount lost over the historic mining period likely to be much higher. The processing of pyritic ores also concentrated mercury losses in a small number of mining centres, including Bendigo, Ballarat, Castlemaine, Clunes, Maldon and Walhalla. This analysis provides a basis for further research needed to support improved management of legacy mine tailings.

Transferencia tecnológica para la producción limpia en la minería de materiales aluviales en La Guajira, Colombia


 Objetivo: Analizar la transferencia tecnológica para la producción limpia en la minería de materiales aluviales en La Guajira, Colombia. Metodología: La investigación fue de tipo descriptiva, con diseño no experimental, transeccional y de campo. La población estuvo conformada por tres empresas: Agregados Río Negro, Valores y Contratos S.A. “Valorcon S.A.” y La Macuira Inversiones y Construcciones S.A, que conforman el sector de la minería de materiales aluviales en La Guajira. Para la recolección de datos se utilizó como técnica la encuesta, empleándose como instrumento dirigido a los informantes, con preguntas cerradas y cinco alternativas de respuesta, constituido por 49 ítems. Se aplicó la validez de criterio con expertos, luego se realizó el cálculo de la confiabilidad a través del coeficiente Alfa de Cronbach, obteniéndose un valor de 0,90. Resultados: Se encontró que la mayor parte de la población realiza la transferencia directamente con el proveedor de la tecnología, es decir solo intervienen un receptor y quien provee, la población estudiada a veces asiste a ferias y congresos para obtener información sobre nuevas tecnologías, y entre las barreras se destaca que gran parte de la población no utiliza tecnologías adecuadas para la producción limpia. Conclusiones: La transferencia de tecnología en las empresas estudiadas estuvo enmarcada por las carencias de tecnologías que propicien una producción limpia, el factor competitivo de la tecnología y aumento de la calidad de los proyectos.

THE ENVIRONMENTAL IMPACT OF THE CIZMA - BĂIUȚ FIELD EXPLOITATION AND THE IMPLICATIONS IN THE DEVELOPMENT OF OTHER PROJECTS DUE TO THE INCLUSION IN THE PROTECTED AREA

The topic presented in the paper refers to two significant aspects regarding the impact of mining operations on the environment and the development of an alluvial mining project in the affected area. The mine waters that drain from the Cizma mining perimeter have an acidic character with a pH of 2.5 at the exit of the gallery with a load of heavy metals in ionic and precipitated form, discharging into a mountain stream, which later reaches in the area of some communities. The perimeter is located in a protected area, which encumbers exploitation projects in these areas.

Comparing the environmental sustainability of two gold production methods using integrated Emergy and Life Cycle Assessment

Abstract Emergy analysis and combined emergy and Life Cycle Assessment (EM-LCA) were used to evaluate the sustainability of an open-pit gold mine and an alluvial gold mine in Colombia. The emergy is the work done to support the gold production separated into renewable and non-renewable energy, and also into those associated directly with the mining and those due to imported resources. The EM-LCA is a new extension of emergy that incorporates the work done by the environment to assimilate airborne and waterborne pollutants. Emergy Sustainability Index values 5 can be considered sustainable. The open-pit and alluvial mines were found to have Emergy Sustainability Index values of 0.02 and 0.04 respectively using emergy accounting, and 0.002 and 0.035 using EM-LCA. The low values from the emergy analysis are mainly due to the large amount of imported resources required by the gold production. The open-pit mine uses a more highly industrialized process and hence relies more on imported resources and less on renewable resources. Open-pit mining also generates more emissions hence its comparatively low EM-LCA rating. The results demonstrate the need to implement management policies that encourage a higher dependence on renewable resources and to reduce reliance on imported resources, as well the need for technologies that lower emissions. It is also concluded that the novel EM-LCA approach has the potential to extend emergy analysis to incorporate emissions. The study also highlights the limitations of emergy accounting for coherent assessment of mining projects.

A checklist of rheophytes of Cameroon.

Rivers in Cameroon were surveyed to collect and document rheophytic plants. Rheophytes are the dominant aquatic macrophytes in tropical river systems, where they are adapted to extreme environments of rushing water (e.g., river rapids, waterfalls and flash floods). Rheophytic plants are useful indicators of river health. However, their habitats are threatened by human activities such as agriculture, plantation development, alluvial mining and dam construction, particularly in tropical countries. In this survey we documented 66 rheophytic species in 29 genera and 16 families. Two ferns, 8 monocotyledons and 56 dicotyledons were listed. Apart from the Podostemaceae family in which all species are rheophytic, the other 15 families have few species which are rheophytic. Five of these families have up to four species and the remaining 10 have only one member as a rheophytic species. The conservation status of each species is assessed and discussed. This work urges botanists, conservationists, and policy makers to do more to protect the habitats of rheophytes and put in place strategies and action plans for the conservation of this important biological group.

The Pilgangoora Lithium-Tantalum Deposit - Geological Overview and Evolution of Discovery

The Pilgangoora Lithium-tantalum pegmatite deposit with a total resource of 156.3 Mt grading 1.25% Li2O and 128ppm Ta2O5, is a globally significant hard-rock lithium-tantalum deposit. The deposit is located in the East Pilbara Terrane of the northwest Pilbara Craton in Western Australia. The Northwest Pilbara Craton is one of the world’s major lithium-tanatlum provinces with large scale lithium-caesium-tantlum bearing pegmatites located at Mt Francisco, Wodgina, Pilgangoora and Strelley. Pegmatites bearing columbite-tantalite at Mt. York were first described in government geological surveys in 1906. Subsequent interest in the pegmatites focussed on their tin and tantalum mineral potential, with small scale hardrock, eluvial and alluvial mining, chiefly in the period 1947-1978. Larger scale alluvial and eluvial mining of tin-tantalum was carried out over 1978-1982 and 1992-1996 by a number of junior companies. In May 2014, Pilbara Minerals acquired the Pilgangoora Project for its lithium potential and has since drilled over 1450 holes for approximately 120,000 metres. The Pilgangoora pegmatite intrusions crop out in a well exposed greenstone belt, with little weathering at surface. Exploration drilling programs along with detailed geological mapping of the Pilgangoora tenement group has provided a better understanding of the geological setting of the fractionated pegmatite intrusions within the East Strelley greenstone belt. This work has led to the recognition of some valuable exploration criteria that may be applied locally to locate additional resources and, longer term, may be used more strategically to review other pegmatite fields across the Pilbara region.

Discovering of high potential zones for gold mineralization using remote sensing satellite data: Mersing, Johor Bahru, SE Malaysia

Mersing is a highly prospective region for gold mineralization in the state of Johor Bahru, which is located on the south-eastern coast of Peninsular Malaysia. The Malaysian Geological Survey identified a widespread geochemical anomaly that follows the north-west regional structural trend running for more than 30 kilometres, commencing near the beach at Kampung Sri Pantai running inland toward the Mersing town. The presence of widespread quartz veining within the highly deformed metasediments, sulphide mineralization and free gold showing in the vein material, and the evidence of substantial alluvial mining and processing activities indicate that the Mersing region has potential to host primary gold mineralization. To date, the area has not been systematically explored using recent remote sensing technology and geological investigations for its primary gold potential and no production details are available. Whilst there are few geological studies in the Mersing, comprehensive remote sensing investigation for identification of high potential zones of gold mineralization in this region is largely lacking. In this study, the application of recently launched remote sensing data such as Sentinel-1and Landsat-8 OLI/TIRS data for locating high potential zones for gold mineralization in Mersing region have been evaluated. High potential zones of gold mineralization associated with the intersection of N-S, NE-SW, NNW-SSE and ESE-WNW faults and curvilinear features in shearing and alteration zones were detected and accurate and up to date structural and geological maps for the region were produced. Results indicate that systematic image processing techniques could be implemented to recently launched satellite data for geological structures and lineament analysis and hydrothermal alteration mapping at both regional and district scales. This investigation provided useful information for gold discovery in tropical environments using integration of remote sensing satellite data.

Fish Community Assemblages of Mining-Impacted Freshwaters at Prestea, Ghana

The study evaluated the fish community assemblage in the sections of the Subri river, the Ankobra river, and the “galamsey” pond within the Prestea community as impacted by alluvial mining activities. Gill nets of length 10 m and mesh size 1.27 cm were used to trap fish of average length 25.25 cm whilst cane baskets were used to trap fish of average width 10.40 cm using the catch and recapture method. All the 46 fish samples identified belong to 10 genera and 5 families. The Chichlidae was the dominant family, accounting for 60% of the total families observed. With an H’ index of 1.57 the Subri river had the most fish diversity in comparison with the Ankobra river and the “galamsey” pond, which had 1.21 and 0.71, respectively. Similarly, the Subri river had a more complex fish community structure than the Ankobra and “galamsey” pond. The dominant species, Oreochromis niloticus, has not yet been evaluated by the IUCN, but the least dominated Brienomyrus brachyistus could be regarded as “least concern”. Notwithstanding, these fish are essential for food by the local communities. There is a possibility that the alluvial mining might have influenced the complexities of fish species communities. Thus conservation efforts must be promoted to sustain fish communities and overall freshwater ecosystem health.

Mapping, Characterization and Dispersion of Metallic Pollutants within a Catchment of Illegal Gold Mining Activities in Ghana

The illegal gold mining activities prevalent in most part of Ghana have caused substantial havoc to the environment especially water bodies which serve as sources of water for domestic, industrial and agricultural purposes. The Ghana Water Company Limited (GWCL) recently shut down their water treatment plant due to the extreme pollution and high cost of treatment. This study focusses on the impact of mining activities on water quality of the affected water bodies, to assess the level of pollution of the river sediments and the extent of dispersion of the heavy metallic pollutants and to map out areas within the Konongo Municipality where illegal mining activities are prevalent. In this regard, both water and sediment samples from two rivers namely; Owerri and Asuokofi in Konongo (in the Asante Akim Central Municipality) were collected at different locations and analysed using Flame Atomic Absorption Spectrometry (FAAS) to assess the concentrations and dispersions of metallic pollutants. Geographical Positioning System (GPS) coordinates of these sample locations were also taken for mapping the sampling points and area. Four different metals; mercury (Hg), Lead (Pb), Arsenic (As) and Cadmium (Cd) were analysed. For sediments, the mean levels of Pb, Hg, As and Cd for the owerri river were found to be 52.2±2, 0.3±0.5, 492±365 and 1.7±2.0 mg kg?1 respectively; whilst those for Asuokofi river were 12±0.7, 2.7±0.4, 21.2±13.5 and 1.6±0.4 mg kg?1 respectively. The mean levels of Pb, Hg, As and Cd for water of the owerri river are respectively 2.5±3.7, 0.20±0.4, 0.28±0.2 and 3.1±0.4 mg L?1; whilst those for Asuokofi river were 8.2±1.3, 2.3±1.8, 25.4±22.2 and 0.45±0.7 mg L?1 respectively. Comparing these levels with the WHO standards for water discharges, these concentrations far exceeded the recommended values. This will impact negatively on the quality of both rivers with dire consequences since they serve as the main raw water resource for drinking water production. Samples of sediments and water from the upstream of these rivers where no activity of alluvial mining is taken place were recorded and they showed lower levels of these metals. It can therefore be concluded that the activities of alluvial gold mining in the study area impacts negatively on both the quality of water in the river and the sediments thereof.

Numerical simulation of the dynamics evolution of alluvial mining quarries

Alluvial mining quarry (or placer mining) is one of the main techniques for extracting important building materials such as sand and gravels. Prediction of quarries detrimental effects on the hydraulic regimes of rivers, in particular on flow regimes, has been carried on in full details in 0, 1 and 2D problem formulations (in the latter case, a depth-averaging is applied). However, the prediction of the quarry behavior itself is unfeasible, though such information would be of paramount importance for estimating the adverse effect on the river bed. This work studies the dynamics evolution of alluvial mining quarries in the framework of two-dimensional formulation based on width-averaging. The Euler multiphase model, which allows simulating separately the behavior of several interacting phases, is implemented. The conducted numerical experiments show that the upstream part of the quarry is eroded more intensively than the downstream one, displacing the quarry up-stream. This effect was observed during numerous field case-studies.

Alluvial mining and its impact on deterioration of physical health of Malekhu Khola, Central Nepal

The Malekhu Khola is accessible and potential for the construction materials in today’s developing phase. The study mainly concerns with mining of construction aggregate and effect of indiscriminate mining from river and its basin area which may impose many harmful effects on environment. The objective of the study is to identify the condition of river using morphological and physical parameters, and to investigate the factors which are directly responsible for the environmental degradation. Such study of rivers in present context is essential as it provides insights of strength of the river. To examine the circumstance of river, the study was proceed by selecting the area into three reaches of each 500 m, and further each reaches are divided into six transects. Both reach-scale and transect-scale attributes were assessed. The scoring was done by adding all the attributes of the standard survey sheet. A cross-sectional study was carried out along 3 different stations, Reach 1 to Reach 3 from upstream to downstream. Various fluvial parameters and data from pebble count were used to calculate morphological parameter and grain size distribution. The channel sediments were found to be extremely poorly sorted, the distribution of grain size is varied from transect to transect, which might be the result of unplanned mining. All the result acquired from field study and satellite image confirms that the river is worsening day by day. The formation of pools and deposition of organic matter show that the river is not flowing in its natural way. After all the examination, it indicates that the Malekhu Khola is being violated by the human and mining activities, thus the river reclamation measure is required at abandoned mining sites to maintain the Malekhu Khola channel morphology and habitat of the river.Bulletin of the Department of Geology, Vol. 18, 2015, pp. 59-66

Alluvial Gold Mining Sites as Exposure Pathways for Methyl Mercury Toxicity in Children: A Systematic Review

Extensive studies have showed that alluvial gold mining is a predisposing factor for mercury toxicity through occupational exposure. In our systematic review of related literature, we aim to determine if children of alluvial gold miners were at risk of exposure to methyl mercury toxicity through dietary exposure. This was achieved through applying Cochrane PICO methodology for the research question. We selected only the most relevant articles from the thousands of articles that were generated by the Divine Word University (DWU) electronic data base system for our review. Further screening questions were applied based on the CASP method which filtered remaining 105 to only 9 papers for the review. The results from the nine (N = 9) studies analysed showed convincing results of the association between consumption of fish contaminated with methyl mercury and poor growth and development in children whose parents lived near mining sites. We conclude that since mercury is the predominant element used in the extraction of gold in alluvial mining, it is an exposure pathway for methyl mercury toxicity for children through dietary exposure.

Remote sensing landscapes of water management on the Victorian goldfields, Australia

The integration of remote sensing technologies, GIS and mobile mapping platforms is producing new insights into the archaeology of historic water management systems. Our case study of the gold rush in 19th-century Victoria, Australia, has identified ditches, dams, mining claims and sediment sinks at site and landscape scales that are normally obscured by dense vegetation. New technologies including LiDAR provide solutions to these challenges and make possible the analysis and interpretation of these spatially diffuse but historically linked sites. For the first time it is possible to record and analyse a complex archaeological landscape in north-east Victoria that is the result of alluvial mining activity in the later 19th and early 20th century. This approach offers a significant advance in Australasian archaeological science and provides an important model for other researchers examining industrial landscapes.

Cornish tin-streamers and the Australian gold rush: technology transfer in alluvial mining

The Cornish are known around the world for their mining skills. In the 19th century the migration of Cornish mining families created a diasporic community with settlements in the United States, Mexico, South Africa and Australia centred on copper, tin and gold mines. While the Cornish are generally associated with underground mining, recent research in Australia suggests that ancient methods for working surface tin deposits played an important role during the gold rush. The identification of Cornish tin-streaming as the source of alluvial mining technology in Australia sheds light on a little-documented branch of mining that has played a significant role in shaping the landscape of goldfields regions.

Analysis of surface mining subsidence laws under thick alluvial Quandian Mine

In order to study the laws of surface subsidence due to mining coal under thick alluvium of Quandian mine, two survey lines were designed on the surface above the first face. By analyzing the position of the maximum subsidence point of the tendency survey line, the zenith angle was obtained, and the correctness of taking bedrock thickness instead of average mining depth to design the position of the trend survey line in the mining area was confirmed; and based on the analyses of the measured data, the critical size of the gob full opening in the geological and mining conditions didn't follow the general law that the gob would reach the critical size when the panel has moved for a distance of 1.2H0 - 1.4H0. These results showed that the bedrock played a major role in the spread of whole overburden subsidence in the geological and mining conditions, while the loose layer had less affection. In addition, based on the analyses of the measured data, some rock movement parameters and probability integral prediction parameters of the surface subsidence of Quandian mine in the geological and mining conditions have been obtained. The study would have some important theoretical significance and practical guidance for implementing mining beneath buildings, water bodies and railways and prevent of this coal field as well as surface structure damage control.

The Application of Surrounding Rock Controlling Technology on Mining of Alluvium Coal Pillar

In the alluvial coal pillar mining process, aiming at water prevention and cure, surrounding rock support, construction technology, safety management and the other main factors of safety mining, and through constant practice, the paper summarized the special measures of rock control on safety mining of alluvium coal pillar in the complex conditions for ensure safe of working face in alluvium corner coal, efficient mining, improve resource recovery. The economic and social effectiveness is remarkable.

Reestablishing a Keystone Species in an Arid Coastal Environment: Saltbush (Salsola nollothensis) in Namibia

Beach hummocks are important ecological components of coastal ecosystems. Although hummocks are naturally adapted to harsh conditions, reestablishing them in arid areas poses great challenges. During a collaborative project, researchers from Namdeb Diamond Corporation and the Millennium Seed Bank Partnership investigated practical methods to reestablish saltbush ( Salsola nollothensis ) beach hummocks to restore areas disturbed by alluvial diamond mining. With focus on simple methods that can be implemented over large areas, collecting seed-containing debris, placing windbreaks, and seeding these with debris are some of the means currently investigated. Preliminary findings indicate that seed quality may deteriorate quickly if seeds are stored in ambient conditions, and storage under controlled conditions and/or seed harvesting shortly before restoration is recommended. Laboratory tests indicate a naturally high proportion of empty seeds, possibly short seed longevity, and that seeds must not be buried too deeply for seedling emergence. Further, seasonal and site-related variation in seed production influences the quality and amount of viable seeds available. All this suggests a complex set of environmental conditions that have to be met to achieve natural recovery or restoration goals. This project illustrates the benefits of partnerships in restoration that made it possible to investigate practical field questions with scientific sophistication, making an international initiative relevant to applied restoration ecology in a developing country.

Natural and mining-related mercury in an orogenic greywacke terrane, South Island, New Zealand

Mercury (Hg) is naturally present in warm springs and mesothermal (orogenic) gold-bearing quartz vein systems in the South Island of New Zealand. Mercury amalgamation was used historically in ore processing at gold (Au) mines, resulting in composite natural and anthropogenic Hg signatures at these sites. This study compares natural Hg enrichment of the Au vein systems, residual anthropogenic Hg added for amalgamation, and enrichment of naturally present Hg during ore processing. Mercury concentration data are presented for solids and water at historic mine sites, the modern Macraes mine, fault-related warm springs, and zones of naturally occurring cinnabar and Hg-bearing Au. Arsenic (As) concentrations are also presented, as As is the most environmentally significant element in this tectonic setting. Tailings and processing residues at historic mine sites (Blackwater mine, West Coast; Golden Point and Golden Bar, Hyde-Macraes shear zone) contain up to 1000 mg/kg Hg, and in adjacent surface waters Hg is at or slightly above background from 0.6 to 0.8 ng/L. Relative to South Island Hg, As is more environmentally significant: solid wastes at some historic mine and mineral processing sites contain up to 30.5 wt% As due to enrichment of natural As in mineralised rocks. Shallow groundwater and processing waters at the modern Macraes mine are up to 0.01 mg/L Hg due to natural Hg in mineralised rocks, and no significant Hg elevation is evident in nearby surface waters, which are <1 ng/L Hg. Mercury concentration in historic mine residues is 103 to 104 times higher than primary ore, and Hg is disproportionally increased relative to As, indicating that much of the Hg was added during the amalgamation process. Natural cinnabar deposition from warm springs results in localised, strongly elevated Hg, equal to or less than the Hg contents in historic mine processing residues. Warm spring precipitates are up to 111 mg/kg Hg and waters are 0.3 µg/L Hg, comparable to data reported for active North Island geothermal (epithermal-style) systems. Natural Hg content in the Au-bearing vein systems results in minor elevation of dissolved Hg in some catchments. South Island Au occurs as an Au-Ag-Hg alloy, up to 8.4 wt% Hg. Cinnabar (HgS) occurs in mesothermal-style veins and as detrital grains in Quaternary gravels hosting Au-Ag-Hg alloy. The Nevis River catchment water, which locally flows through gravels containing cinnabar and Hg-bearing alluvial gold, contains up to 7 ng/L dissolved Hg. This is rapidly diluted to near 3 ng/L by low-Hg waters, and no effects of anthropogenic Hg addition near alluvial mining areas were detected; the dissolved Hg is likely derived from Hg-bearing gold. Mobilisation of Hg from study sites to downstream environments is at least partially controlled by solubility of cinnabar and elemental mercury.