Use Of Mining Waste Research Articles

Sorption of heavy metals by the filtering containers with serpentine materials

The search for effective technologies for the remediation of technologically polluted natural objects is an urgent problem of environmental protection. At the experimental site near Kola MMC JSC (Murmansk region, Monchegorsk), experiments have been carried out on the use of mining waste to create phyto-adsorption sites in technologically polluted territories. During the experiments, filtering modules were used to study the processes of sorption/desorption of emission components with vermiculite-sungulite composition materials obtained by enriching phlogopite mining waste (Murmansk Region, Kovdor). To load two types of filtering modules designed to study open (I) and partially open (II) systems, the authors have used the initial and heat-treated granular sungulite, as well as slurry products (the content of sungulite and vermiculite was 30 %). As a control option, an experiment has been carried out using pure peat, selected in the vicinity of Apatity (Murmansk region). As a result of the study, the layer-by-layer content of the acid-soluble (or semi-gross) form of the components has been determined; the toxicity module has been calculated (the ratio of the total molar content of metals (Cu + Ni) and macronutrients (Ca + Mg)) used to assess the possible toxic effect of products in relation to plants. Pure peat has proved to possess the greatest sorption ability, however, at the end of the experiment, the highest degree of toxicity has been observed for peat; mineral products have been the least toxic. An analysis of the distribution of metals among the layers of filtering modules (II) has shown that intense accumulation of metals is observed in the upper layers; with increasing depth (layers 2-4) there is a gradual decrease in the copper content, in some products nickel is leached in the lower layers. The results of the study have shown that for loading phyto-adsorption sites it is advisable to use a granular sungulite product characterized by good sorption ability and low toxicity.

Use of Mining Waste to Produce Ultra-High-Performance Fibre-Reinforced Concrete.

This research work analyses the influence of the use of by-products from a fluorite mine to replace the fine fraction of natural aggregates, on the properties of Ultra-High-Performance Fibre-Reinforced Concrete (UHPFRC). Replacing natural aggregates for different kinds of wastes is becoming common in concrete manufacturing and there are a number of studies into the use of waste from the construction sector in UHPFRC. However, there is very little work concerning the use of waste from the mining industry. Furthermore, most of the existing studies focus on granite wastes. So, using mining sand waste is an innovative alternative to replace natural aggregates in the manufacture of UHPFRC. The substitutions in this study are of 50%, 70% and 100% by volume of 0–0.5 mm natural silica sand. The results obtained show that the variations in the properties of consistency, compressive strength, modulus of elasticity and tensile strength, among others, are acceptable for substitutions of up to 70%. Therefore, fluorite mining sand waste is proved to be a viable alternative in the manufacturing of UHPFRC.

Coal mining waste in Poland in reference to circular economy principles

The article deals with the problem of mining waste, which is the largest group of waste balance in Poland. Based on research, the current state of waste management in Polish coal mining has been identified. This is a challenge that is facing not only the domestic mining industry, but also international mining. As demonstrated using the example of international solutions, the essence of waste classification is gaining practical significance. A dynamically developing, more flexible and advanced technology enables the 3R principle (Reduction, Reuse, and Recycle) of Circular Economy theory to be applied in practice to the mining industry. Coal mining waste generated due to the absence of selective mining methods and coal beneficiation can be reused in co-firing processes for energy production after being treated. Further reuse of coal mining waste also has a positive effect on land reclamation and restoration, which in turn will minimize the size of mining dumps. Non-energy uses of coal may be found in the chemical industry, but some production methods may raise additional questions regarding excessive CO2 emissions. In a circular economy, it is important to identify all possible ways to reuse resources. As part of the research, the current state of coal mining waste was examined. Based on the described solutions for the use of mining waste, a sustainable, socio-environmental CE strategy for this group in the selected area of waste has been proposed together with the highest and best use analysis for dumps in complex legal, economic and technical conditions.

Composite binders from mining waste

The possibility of obtaining composite binders with the addition of mining waste represented by magnesium silicate rocks is considered. They are low active in their natural state. Mechanical activation of raw mixtures was used during carrying out of research works. It was found that with increasing mechanical activation time from 1 minute to 20 minutes, the specific surface of the raw mix increases, the chemical activity of the surface layer increases. It helps to accelerate the solid-phase reactions with the formation of silicates such as diopside, monticellite, mervinite. The optimal time of mechanical activation was determined, at which the largest amount of mixed calcium, magnesium and iron hydrosilicates was noted in the hydrated system. The formation of these products of hydration causes high physical and mechanical indicators of binding compositions. It was found out that during 15 minutes of grinding the raw mix, the flexural and compressive strength of binding compositions at the age of 28 days of normal-humidity hardening reaches a maximum value. The use of mining waste in the production of building materials allows us to obtain new types of products. At the same time, environmental problems associated with the placement of technogenic raw materials are solved.

Towards circular economy in mining: Opportunities and bottlenecks for tailings valorization

Current management of mining waste is based on linear economy thinking. However, the use of mining waste as a raw material resource can be one solution to the limited metal supply. The objective of this study was to fill in the knowledge gaps of business opportunities, drivers, needs and barriers for tailings valorization, since the transformation towards a circular economy needs advancements in understanding these factors. Based on a workshop and theme interviews, the utilization of tailings in the mining industry is currently in its infancy, but there is clear raw material potential for the future. The handling of sidestreams at mine sites depends on mine lifecycle. The identified opportunities and drivers were categorized under the circular economy mindset, technological, environmental, institutional and economic drivers. The needs were new value chains, technology development, the decrease in the amount of waste, stability, taxation, and predictability of regulation. Challenges and bottlenecks were categorized under new value chains, technological, environmental, institutional, economic and knowledge bottlenecks. The identified needs and barriers need to be properly addressed to speed up the transformation towards the circular economy in the mining industry.

Thermal insulation composite with the use of mining waste

The authors offer the use of environmentally friendly waste of mining plants located in the Arkhangelsk region as a binder to create a thermal insulation construction composite based on basalt fibers. This waste is the saponite-containing material (SCM) recovered from recycle water suspension produced during the enrichment of kimberlite ores from the diamond deposit named after M V Lomonosov (Arkhangelsk region). The SCM has binding properties and they depend on its dimensional characteristics and reach optimum values at an average particle size within 1-2 µm. The test samples of composites obtained at 105 0C with the SCM content varying in the range from 7.5% to 25% and the test samples of composites obtained as a result of thermal modification at up to 1200 0C with the SCM content varying in the range from 15 to 25%, were made under laboratory conditions. The raw mix for thermal insulation composite production contained the SCM as a binder with an average particle size of 1-2 µm, and basalt fibers with an average diameter of 3-6 µm as fibrous filler. Thermal modification of samples was carried out at a temperature up to 1200 0C according to the temperature-time mode used in expanded clay production. As a result of tests, it was found that the composite thermal insulation capacity decreases and compressive strength increases with an increase in the SCM content. Additionally it was noted that thermal modification of thermal insulation composites considerably increases their compressive strength without any impact on the heat transfer coefficient. Thus, it is possible to obtain materials with the specified performance such as the heat transfer coefficient and compressive strength by regulating a percentage ratio of components of the thermal insulation composite based on basalt fibers – the saponite-containing material. Additionally, thermal modification of the studied composite makes it possible to increase considerably compressive strength without changing its heat transfer coefficient. The obtained thermal insulation construction composite is environmentally safe and can withstand high temperatures without breakdown. The SCM will promote the effective solution of environmental problems associated with the development of the diamond deposit named after M V Lomonosov.

Methodology of statistical study of the chemical composition of by-products of coal mining to assess their suitability as materials for reclamation

Abstract The results of the research presented in earlier works with the participation of the authors (Klojzy-Karczmarczyk et al. 2016a, b, c) indicate the possibility of the use of mining waste from Janina Coal Mine (Upper Silesian Coal Basin, Poland, TAURON Wydobycie S.A.) or products (aggregates) produced on the basis of gangue for technical reclamation. It is essential for this process to obtain a material with low total sulfur, and it has been shown that the best quality parameters are obtained for the material subjected to modification by the rejection of fine fractions. In this work, the lower limit of the material’s fraction was determined using statistical analysis, wherein with the predetermined but low probability of error, the content of contaminants (sulfur, as well as other elements) does not exceed the allowable limit (reference value). To solve this task, 3 different statistical methods were used: evaluation of guaranteed contents (the maximum for a given degree of probability) of the polluting components, the results of statistical hypotheses testing and analysis of correlation and regression. The applied statistical methods produce results very proximate to each other. In the presented case study for the Janina coal mine based on the results of a statistically small sample (<30 observations) rock material fraction> 20 mm may be considered as safe for the purposes of reclamation, and the material fraction >25 mm as very safe. It cannot be ruled out, however, that this limit may be reduced to a diameter of 16 mm. The content analysis of 11 elements (As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, V, Zn determined as total content in the secondary samples for the fraction 10-200 mm (the fraction >200 mm was not present) showed that they are lower than the allowable limits specified by relevant legal regulations. For this fraction, exceedance of the limit values of sulfur content is, however, highly probable. For this reason, the primary criterion for determining the suitability of the waste material for the purposes of reclamation should be the total sulfur content, and the determination of the lower limits of the material fraction that meets the environmental requirements should be conducted using statistical methods based on the results of experimental sampling of rock remaining after coal preparation. The use of advanced methods of statistical analysis may facilitate the design of technological processes, leading to obtain industrial quantities of high quality, appropriately graded reclamation material.

Mining Wastes in the Buryat Republic and Prospects of their Use

Case study of prospects of use of mining wastes in the Buryat Republic. High quality heavy weight concretes can be produced with the use of refuse from the tungsten and molybdenum refining plant. Brown coals, being one of overburden rocks of coal pits, are a good raw material for organic-mineral fertilizers, as well as for new sorbents. Ash and slag wastes generated by burning of solid fuels are widely used in production of construction materials. Separation of ashes into magnetic and non-magnetic, which allows to expand their application scope, is deemed promising.

Biosourced polymetallic catalysts: an efficient means to synthesize underexploited platform molecules from carbohydrates.

Polymetallic hyperaccumulating plants growing on wastes from former mining activity were used as the starting material in the preparation of novel plant-based Lewis acid catalysts. The preparation of biosourced Lewis acid catalysts is a new way to make use of mining wastes. These catalysts were characterized by X-ray fluorescence, X-ray diffraction, inductively coupled plasma mass spectrometry, and direct infusion electrospray ionization mass spectrometry. These analyses revealed a complex composition of metal species, present mainly as polymetallic chlorides. The catalysts proved to be efficient and recyclable in a solid-state version of the Garcia Gonzalez reaction, which has been underexploited until now in efforts to use carbohydrates from biomass. This methodology was extended to various carbohydrates to obtain the corresponding polyhydroxyalkyl furans in 38-98% yield. These plant-based catalysts may be a better alternative to classical Lewis acid catalysts that were previously used for the Garcia Gonzalez reaction, such as ZnCl2 , FeCl3 , and CeCl3 , which are often unrecyclable, require aqueous treatments, or rely on metals, the current known reserves of which will be consumed in the coming decades. Moreover, the plant-based catalysts allowed novel control of the Garcia Gonzalez reaction, as two different products were obtained depending on the reaction conditions.

Utilização do resíduo da extração de esmeraldas em uma formulação de massa de revestimento cerâmico

Empresas envolvidas na mineração de esmeralda e beneficiamento representam uma importante área de desenvolvimento industrial no Brasil, com significativa contribuição para a produção mundial desse minério. Como resultado, grandes volumes de resíduos de esmeralda são constantemente gerados e abandonados no ambiente, contribuindo negativamente para a sua preservação. Por outro lado o interesse no uso do resíduo de mineração como aditivo na produção de material cerâmico tem crescido entre os pesquisadores nos últimos anos. A indústria cerâmica está constantemente buscando a ampliação do mercado para o setor e tentando aperfeiçoar a qualidade dos produtos e aumentar a variedade de aplicações. A tecnologia de obtenção de cerâmica de revestimento que usa resíduos de mineração é um mercado ainda pouco explorado. Neste cenário, o objetivo do presente estudo foi caracterizar o resíduo gerado a partir de mineração de esmeralda, bem como para avaliar seu potencial uso como matéria-prima fundente para a produção de revestimentos cerâmicos. Misturas cerâmicas foram preparadas a partir de matérias-primas caracterizadas por fluorescência de raios X e difração de raios X. Cinco composições foram preparadas utilizando índices de resíduos de esmeraldas de 0%, 10%, 20%, 30% e 40%. As amostras foram preparadas por prensagem, sinterizadas em 1000, 1100 e 1200 ºC e caracterizadas visando estabelecer sua composição mineralógica, absorção de água, retração linear e módulo de ruptura à flexão. Os resultados mostraram que o resíduo de esmeraldas estudado pode ser incorporado na massa de revestimento cerâmico até 20% em substituição ao feldspato sem comprometimento das propriedades do produto final.