Academic literature on the topic 'Coal tailings dam'

For safe and efficient mining operations to occur the management of waste materials is required, which often takes the form of geotechnical structures constructed from this waste. The safe use of these structures requires a number of resources, one of these being sufficient information about the waste material properties. For example, the drying process of a tailings dam is predicted with the water retention and permeability of the tailings. When considering coal tailings, which are comprised of coal and mineral soil particles (typically), the presence of coal may be problematic. The localised hydrophobicity of coal molecules may have a unique effect on water permeability and retention; this is relevant to geotechnical analysis where hydrophilic behaviour is assumed. To explore the possible effect of localised hydrophobicity, mine tailings were obtained from a coal mine of the Hunter Valley, NSW, Australia, and the coal fraction was separated via density separation. After this, three materials were available: unchanged mine tailings and a coal and mineral fraction of tailings. The goal was to characterise the three materials and allow deeper insight on what effect the addition of coal has on retention and hydraulic properties. Characterization involved measuring particle size distribution, pore size distribution, soil water retention curve, and saturated water permeability. The results show that there are distinct differences in the water retention and permeability properties of each material, and a number of these differences could be explained by the differing particle/pore sizes observed in each material. However, the coal containing materials desaturated at low suctions (< 10 kPa) compared to the mineral fraction, which could not be explained by particle/pore size differences and points towards localised hydrophobicity as a possible cause.

Introduction. Disposal of recycled materials is targeted at saving the natural resources and reducing the volume of wastes that have to be disposed of in special landfills. Disposal is encouraged by many countries of the European Union. A key element in promoting of wastes recycling is the «polluter pays» principle, which has been included in all Community directives regarding management of safe and hazardous wastes. In order to encourage recycling, many Member States have adopted specific environmental legislation, in particular, the wastes disposal tax.Problem statement. Today, in Ukraine the issue of utilization of industrial wastes has not been solved, that is why a considerable part of them are in the dumps and pose a great risk for the environment; and only a small part of them is utilized in the construction projects [1], although there exists the «State Target Economic Program for the Development of Public Roads of National Significance for 2018–2022» [2] and the Order of the Cabinet of Ministers of Ukraine [3] which regulate the use of local materials, including industrial waste during the construction of motor roads. At the same time, millions of tons of dusty wastes are being produced at the Ukrainian power plants as a result of coal combustion — fly ash and ash from a tailings dam.Purpose. Carrying out of research of ash from a tailings dam and a mixture of limestone material with the ash from the tailings dam on conformity with the requirements to fillers.Materials and methods. The ash from a tailings dam, a mixture of limestone material with the ash from a tailings dam and commercially produced limestone filler have been selected for the study.Results. The results of the research on establishing the possibility of using the dusty waste products from power generating plants for the production of asphalt mixtures are presented. Experimental studies have been performed to determine the physical and mechanical properties of the ash from the tailings dam with partial replacement by limestone material. The conformity of the studied materials to the requirements of national standards was determined.Conclusions. Studies for determination of grading, porosity, swelling and structuring ability showed that the tested ash does not meet the requirements of Table No.5 of DSTU B V.2.7-121 for porosity in the case of compaction of 40 MPa; a mixture 80:20 — for swelling of samples of the filler with bitumen; and the mixture 50:50 meets the established requirements by defined indicators. A significant swelling increase of the samples from the mixture of filler with bitumen may be the result of high content of clay impurities in the test materials.Keywords: industrial wastes, limestone material, ash, filler. physical and mechanical properties.

A comprehensive systemic approach is needed to make effective decisions for global sustainability. The system’s points of view introduced sustainable development (S.D.) and sustainability in prior years. Sustainable development is expressed as a desire followed by humanity to live in a better condition considering all the limits that nature could have. Social, environmental, and economic responsibilities are the wide-ranging developmental characteristics that form sustainability. In this paper, with the help of search engines like Scopus and Web of Science, several documents related to environmental sustainability in the mining industry were studied. The principal investigated problems were tailings dam failure, forestland use in mining operations, social and environmental issues in crushed stone mining industries, landfill mining challenges, climatic problems, economic problems, and fatalities in artisanal and small-scale mines. Also, a table was designed to categorise these problems and determine the solution and primary goal. This study investigates the severity of mining operation conditions and environmental issues in this industry. The common environmental problems in the mining industry include soil degradation, deforestation, land subsidence, acid mine drainage, waste production, natural landscape destruction, coal production, carbon footprint, dust pollution, greenhouse gas emissions and climatic problems. To have a more sustainable mining industry, all the mining stages, from the exploration to the post-closure stages, must minimise resource and energy consumption and waste products.

In order to analyze variable-mass permeation characteristics of broken rock mass under different cementation conditions and reveal the water inrush mechanism of geological structures containing broken rock masses like karst collapse pillars (KCPs) in the coal mine, the EDEM-FLUENT coupling simulation system was used to implement a numerical simulation study of variable-mass permeation of broken rock mass under different cementation conditions and time-dependent change laws of parameters like porosity, permeability, and mass loss rate of broken rock specimens under the erosion effect were obtained. Study results show that (1) permeability change of broken rock specimens under the particle migration effect can be divided into three phases, namely, the slow-changing seepage phase, sudden-changing seepage phase, and steady seepage phase. (2) Specimen fillings continuously migrate and run off under the water erosion effect, porosity and permeability rapidly increase and then tend to be stable, and the mass loss rate firstly rapidly increases and then gradually decreases. (3) Cementation degree has an important effect on permeability of broken rock mass. As cementing force of the specimen is enhanced, its maximum mass loss rate, mass loss, porosity, and permeability all continuously decrease. The study approach and results not only help enhance coal mining operations safety by better understanding KCP water inrush risks. It can also be extended to other engineering applications such as backfill paste piping and tailing dam erosion.

Os processos envolvidos no beneficiamento do carvão produzem efeitos nocivos para o meio ambiente, principalmente pela quantidade e natureza dos rejeitos que são gerados. Estes rejeitos comumente denominados piritosos, mesmo não apresentando altos conteúdos de pirita, constituem um material ácido que causa efeitos nocivos ao meio ambiente, principalmente aos corpos dágua. Estes rejeitos geralmente são depositados em barragens de rejeitos. Operações de beneficiamento como a flotação, consagrada na recuperação de finos, podem desempenhar um importante papel no processo de recuperação destes rejeitos de partículas ultrafinas. O rejeito carbonoso estudado nesta pesquisa provém da barragem de rejeitos El Cantor, localizada na Colômbia, na mina El Cerrejón. O processo de beneficiamento envolve ciclones de meio denso e espirais. A caracterização revelou que o material possuim teor de cinzas de 56% e poder calorífico de 5.800 BTU/lb, o teor de enxofre é 1,2%. Em termos de granulometria o material é considerado ultrafino já que 63% é menor que 0,014 mm. O conteúdo de matéria carbonosa deste rejeito é facilmente recuperado por flotação, como se demonstra neste trabalho. É possível recuperar 74% da matéria carbonosa e obter um produto com 7,3% de cinzas e poder calorífico de 14.225 BTU/lb em base seca.
The processes involved in coal preparation generate harmful effects to the environment, mainly due to the quantity and nature of the wastes that are generated. These tailings generally called pyritic, not even showing high content of pyrite are an acid material, harmful to the environment. These tailings are usually disposed of in tailings dams. Froth flotation will be important as a coal preparation process to recover these ultrafine particles. The tailings, studied in this work come from a process involving dense medium cyclones and spirals. They have an ash content of 56% and a calorific value of 5,800 BTU / lb, the sulfur content is 1.2%. In terms of size the material is considered as ultrafine as 63% is less than 0.014 mm. The coal matter content of these tails is easily recovered by froth flotation, as evidenced in this work. It is possible to recover 74% of the coal matter and to obtain a product with 7.3% ash and calorific value of 14,225 BTU / lb in dry basis.

 Coal tailings are produced as a waste product from washing the fine < 2 mm fraction of mined coal to add value to the saleable product. After washing, slurried tailings are pumped to holding dams for disposal and desiccation. Once full the core of these dams dry slowly limiting vehicular access for reprocessing or rehabilitation works. In areas where evaporation exceeds rainfall, a dry surface crust, susceptible to generating wind blown dust, develops during this desiccation phase. A revegetation strategy involving establishing vegetation directly on coal tailings was therefore developed, to reduce wind blown dust hazards whilst maintaining the potential for later coal extraction. The field studies for the project were  depth. In the wetland plant available water was adequate for plant growth but the material was poorly aerated where moisture content was high. ... This thesis demonstrated the establishment of salt tolerant vegetation was possible on tailings dam number three at Saraji Mine and, therefore, revegetation with the view of minimising dust and maintaining access was feasible. Treatments that facilitated vegetation establishment in the field were those that decreased salinity and increased plant available water (mulching and irrigation). Nitrogen and phosphorus fertiliser additions were shown to be necessary in the glasshouse. Given that low plant available water and high salinity were the major limitations plant growth, provided follow up fertiliser is applied, trees and deep rooted vegetation should continue to survive and grow once their roots are have developed sufficiently to access the higher moisture/lower salinity sub -surface tailings. With increased vegetative biomass, the volume of leaf litter produced and dropped onto the tailing surface would increase and "self mulching" could occur. Further monitoring to investigate the longer term "self mulching" potential, C. glauca water usage rates and changes in species composition are recommended.