Slag Research Articles

Development of the Technology of Changing the Architecture and Mining Reclamation of Low-profile Small-sized Mine Spoil Heaps and Sites with Coal Mining Wastes Using Draglines

The use of technology of changing the shape of low-profile small-sized mine spoil heaps and open sites with coal mining wastes, poured at the stages of construction is substantiated and the prospects of further exploitation of coal mines are evaluated. Working processes of electric crawler dragline, allowing to refuse the operation of mining transport equipment with diesel engines, which in practice is the basis of mechanization of the whole complex of mining works, are stated. It is concluded that the developed technology, based on the application of draglines with electric drive and increased process parameters of the working equipment in comparison with hydraulic excavators, allows to carry out highly effective special works on changing the architecture of mine spoil heaps and sites with coal mining waste in order to accelerate the restoration of ecological balance on the surface of the latter.

Development of the Technology of Changing the Architecture and Mining Technical Reclamation of High-profile Large-sized Mine Spoil Heaps Using Draglines

The use of technology of changing the shape of high-profile large-sized mine spoil heaps dumped in the process of preparation of coal deposits for underground mining and the prospects of further exploitation is substantiated. The volume of toxic substances emitted into the atmosphere during the operation of mining transportation equipment with diesel engines in the course of changing the landscape architecture and mining reclamation of mine spoil heaps has been determined. It is concluded that the developed technology, based on the application of draglines with electric drive and increased process parameters of the working equipment in comparison with hydraulic excavators, allows to carry out highly effective special works on transformation of slopes of mine spoil heaps in order to accelerate the restoration of ecological balance on the surface of the latter.

Study of Ecological Damage to Natural Landscapes after the Closure of Coal Mines in the Tula Region

The results of the study of ecological condition of disturbed lands during underground coal mining in the areas of the Moscow Coal Basin in the territory of Tula region are presented. According to the data of satellite imagery, the number and areas of mine spoil heaps are determined. It is established that using the existing methods of spoil heaps reclamation, the probability of effective restoration of ecological balance on their surface is very low. The complex of works is proposed for a radical change in the architecture of spoil heap landscapes by means of introduction of new technologies, the practical implementation of which will considerably increase rates of restoration of ecological balance on these technogenic objects left after closing of coal mines.

Study of Disturbed Land Ecology and Economics of Farming after the Completion of Mining Operations in Coal Mines in the Ryazan Region

Study results of disturbed lands ecological state in the course of underground coal mining in the coal-saturated areas of the Moscow Coal Basin in the Ryazan region are presented. The number and areas of mine spoil heaps are revealed, and their influence on the reduction of forest and arable land area is established. The calculation of economic efficiency of farms in the liquidation of mine spoil heaps on agricultural land previously taken out from the turnover for the needs of the coal industry was carried out.

Restoration of Impounded Forests of Coastal Louisiana Using Spoil Bank Gapping

Impoundment and increased flood duration are some of the most common stressors to declining forested wetlands in coastal Louisiana, USA. One type of restoration that has shown itself to be cost-effective is spoil bank gapping. This type of hydrologic restoration has occurred within the Lac des Allemands swamp of Barataria Basin. After 60 years of impoundment, the hydrogeomorphic processes in the study area were improved. The study area included eight paired 625 m2 sites. Basal area growth over the 7-year period varied between 5.93% and 14.39%, with an average of 8.31%, or just over 1% wood growth per year. Post-restoration basal areas indicate that all our study areas are improving. Pooled together, the 2018–2023 years had significantly higher net production than the pre-project 2017 growing season. The distribution between leaf and wood production was remarkably similar within species types across years, with leaf production consistently exceeding wood production, particularly due to Taxodium distichum. Canopy cover has increased by 20 percent since project construction, and as a result, herbaceous cover tends to decrease over time.

Myrmecophilous Aphid Species (Hemiptera, Aphididae) Feeding on Mycoheterotrophic Monotropa hypophegea (Ericales, Ericaceae)

The paper presents the first report and morphological description of aphids feeding on the mycoheterotrophic plant Monotropa hypophegea Wallr. of the family Ericaceae. This is the first known case of aphids feeding on a mycoheterotrophic plant, additionally involved in mutualistic relation with ants Lasius niger (Hymenoptera, Formicinae). This observation took place on an overgrown, postmining spoil tip in southern Poland (Europe). Barcode COI sequencing and morphological examination indicated that the collected specimens of aphids belong to A. fabae s. lat., a group of closely related species. The discussion focuses on taxonomic issues concerning the species identity of the collected aphids and the ecological interactions between insects, plants, and fungi involved in the observed association. The presence of ants attending aphids indicates the possibility of ants serving as pollinators of M. hypophegea.

Unveiling the Potential of Civil Briquette Furnace Slag as a Silico–Aluminon Additive in Alkali-Activated Materials

Civil briquette furnace slag (FS), as a type of industrial solid waste, is not currently being recycled as a resource by the building materials industry. This study focuses on the potential of FS in the formulation of alkali-activated materials (AAMs) compared with calcium carbide slag (CS). This study encompasses three distinct AAM systems: alkali-activated fly ash alone (AAFA), fly ash–slag powder blends (AAFB), and slag powder alone (AABS). Electrical conductivity, fluidity, drying shrinkage, and flexural and compressive strengths were also assessed. Advanced characterization techniques, including SEM-EDS, XRD, FTIR, and TG-DSC, were utilized to examine the morphology, mineralogy, and reaction products. Despite the chemical similarity between FS and CS, FS exhibits limited active chemical components (SiO2, Al2O3, CaO, and MgO) and primarily functions as a physical filler, and thus lacks the chemical binding properties of CS. FS has a positive effect on the long-term compressive strength of the AABS system but not on the AAFA and AAFB systems. The NaOH-activated SP mortar sample with 20% FS reaches a compressive strength of 29.8 MPa at 360 days. The binding strength in AAMs incorporating FS is predominantly attributed to the gel formation within the alkali-activated matrix. This research offers valuable insights into the strategic use and substitution of CS, FS, and other silico–aluminon additives within the context of AAMs development.

Thermophilic and thermotolerant microfungi of coal mine spoil tips beyond the Arctic Circle

Background and aims: Thermophilic and thermotolerant fungi occupy a variety of ecological niches. The purpose of this article is to show that these microfungi are able to live even in such harsh conditions of the high Arctic beyond the Arctic Circle. M&M: Rock from coal mine spoil tips were collected and studied using scanning electron microscopy. The method of direct inoculation was employed to isolate microfungi. The isolates were identified using morphological identification and molecular methods. The growth rate of micromycetes was studied depending on temperature. Results: Eight cultures of microfungi belonging to six species that are able to grow at temperatures of 45 °C and above were isolated from coal mine spoil tips. Conclusions: The data obtained indicate the presence of thermophilic and thermotolerant microfungi in the spoil tips of coal mines beyond the Arctic Circle. All the fungi belonged to the order Eurotiales. These microfungi are able to exist in the harshest conditions with several simultaneous adverse factors.

Zero Wastefor Creative Economy And Tourism In Kolo Asakota Village, Bima City

Garbage is a major problem in the development of beach tourism in Kolo Village, Bima City. Garbage causes beaches to become dirty, beaches become less beautiful, brings unpleasant odors, causes disease and environmental pollution. The results of observations of the state of waste in Kolo Village showed that the prominent waste problems are waste heaps, waste sources, waste sorting, waste storage/TPA, waste transportation, waste destruction, and low compliance/awareness of regional regulations regarding waste handling . The 2024 Mataram University PMD KKN program in Kolo sub-district aims to provide understanding to the community about the importance of the Zero Waste concept, digitize the promotion of Zero Waste Tourism and creative economy MSMEs, train community creativity in processing waste into craft products with selling value. Apart from that, the PMD KKN program is also to promote and maintain the cleanliness of tourist and residential environments. The results of the activity show that the Mataram University PMD KKN program in Kolo sub-district has influenced the community's enthusiasm for implementing zero waste and using recycled waste into products of economic value such as shopping bags (Z-Bags), key chains, and compost for agriculture. It is hoped that the Zero Waste concept will spur community creativity and develop a creative economy and waste-free tourism.

COMPREHENSIVE PROCESSING OF MINERAL RAW MATERIALS FROM COAL MINE WASTE DUMPS: PROPERTIES, VALUABLE PRODUCTS, AND RESOURCE ACCOUNTING SYSTEM

Objective. Experimental studies on the chemical and mineralogical composition of coal mine spoil heaps and the potential for processing them to obtain valuable mineral-raw materials. Development of an analytical tool for accounting and forecasting the resource potential of coal mine spoil heaps. Methods. To achieve the objective, X-ray fluorescence analysis, X-ray phase analysis, granulometric analysis, laboratory studies of mineral raw material enrichment using sieve fractionation and gravity separation, as well as analytical studies of spoil heap resource accounting were employed. Results. The chemical, mineralogical, and granulometric composition of spoil heaps from a coal mine in the Western Donbas region was investigated, enabling the identification of a processing strategy to obtain a range of products: coal concentrate, crushed stone mixture, sand fraction, and clay fraction. It was established that gravity separation of coarse fractions in a heavy medium created with clay slurry demonstrated high separation efficiency, yielding a significant low-ash coal fraction and a high-ash rock fraction. In contrast, spiral separator processing demonstrated significantly lower low-ash coal recovery. A technological processing scheme for spoil heaps to obtain a complex of valuable products was developed, and forecast indicators were evaluated. A methodological system for accounting the resource potential of a coal mine waste dump has been proposed in the form of an informational database. This system allows for tracking changes in the dumps structure, identifying zones of attractive resource accumulation for economic efficiency of processing operations in the long term. Scientific novelty. The use of clay suspension from washed spoil heaps to create a heavy medium for the beneficiation of coarse fractions allows for the recovery of up to 95% coal concentrate with 11% ash content, contributing to resource conservation. Practical significance. A technological scheme for obtaining a range of valuable products for the energy and construction industries has been developed. An analytical tool for resource potential accounting and calendar planning for spoil heap formation has been created, enabling operational identification of resource concentration zones within spoil heaps and their sections. Keywords: coal mine, spoil heap, valuable resource, chemical composition, mineralogical composition, granulometric composition, gravity separation, resource accounting.

Physical and mechanical properties of burnt-out coal mine waste heaps

Physical and mechanical properties of burnt-out coal mine waste heaps

Natural phytomelioration of coal mine waste heaps in the context of increased radiation background (on the case of Nadiya mine, Lviv-Volyn coal basin, Ukraine)

Natural phytomelioration of coal mine waste heaps in the context of increased radiation background (on the case of Nadiya mine, Lviv-Volyn coal basin, Ukraine)

Influences of vegetation types and near-surface characteristics on hydrodynamics and soil erosion of steep spoil heaps under rainfall and overland flow conditions

Spoil heaps, are characterized by loose structure, high infiltration, steep slopes, etc, and have become a source of soil erosion and geological disasters. Vegetation was regarded as an effective way to curb soil erosion of spoil heaps. However, few studies have been conducted to explore the effects of vegetation types and their near-surface characteristics on hydrodynamics and soil erosion of steep spoil heaps. This study aimed to address this research gap by conducting field simulated rainfall and rainfall with run-on experiments using simulated spoil heap plots with 3.4m × 2m × 0.6m (length × width × depth) and a slope of 30 degree. The material used in the spoil heaps comprised a uniform mixture of silt soil particles, constituting 90% by mass, and gravel, constituting 10% by mass. For this study, bare slope (BS), Artemisia gmelinii (A. gmelinii), and Cynodon dactylon (C. dactylon) treatments were designed. Additionally, the grass-covered underwent two treatments: intact grass (IG) and only root (OR). The simulation experiments consisted of two types: rainfall conditions with intensities of 0.8, 1.2, and 1.8mmmin-1, and rainfall with run-on conditions with three intensities and a discharge flow rate of 15Lmin-1. The results showed that: under rainfall conditions, A. gmelinii had a higher soil loss reduction benefit (93.3%) than C. dactylon (88.5%), while the percentages reversed with A. gmelinii at 82.1% and C. dactylon at 91.9% under rainfall with run-on. Moreover, A. gmelinii exhibited higher runoff volume reduction benefits than C. dactylon under both experimental conditions, except for rainfall intensity of 0.8mmmin-1 in IG treatments. The canopy of A. gmelinii accounted for 53% to 69% of the reduction in average soil loss rate, whereas the root and canopy of C. dactylon contributed 58% and 162% under rainfall and rainfall with run-on conditions, respectively. During heavy rainfall events, vegetation could experience more severe soil and runoff loss compared to BS once its aboveground canopy was lost. Furthermore, A. gmelinii had a greater effect in reducing average velocity and increasing resistance coefficient compared to C. dactylon. Additionally, C. dactylon had twice the effect in improving shear stress and stream power than A. gmelinii. Vegetation influences slope sediment and runoff yield by modulating erosion dynamic parameters. This study can serve as a valuable reference and practical guidance for the ecological restoration of similar engineering spoil heaps in the future.

The Inhibitory Tendency of Calamagrostis epigejos and Solidago spp. Depends on the Successional Stage in Postindustrial Vegetation

ABSTRACTIn spontaneously vegetated postindustrial areas, we have limited knowledge of whether the known inhibitory tendencies of herbaceous species—Calamagrostis epigejos and Solidago spp.—vary across successional stages. Our study fills this knowledge gap to assess the inhibitory role of the invasive alien and expansive native species with known behavior from the literature. Specifically, we hypothesized: (i) there will be an inhibitory effect of these species on diversity across successional classes; (ii) the effect of a species will depend on the successional class due to abiotic requirements of plant communities in each successional class. We recorded vascular plant species and their abundance across 400 plots on post‐coal mine heaps in Upper Silesia, Poland. We classified spoil heaps into three successional classes (early‐stage; mid‐stage; late‐stage). We calculated plant community taxonomic, functional, and phylogenetic diversity and, using generalized linear mixed‐effects models, we estimated predictors of diversity indices across successional classes. While we found no limiting effects of these species on diversity indices across successional classes, the effects of a species depended on the successional stage. We found the impacts of Calamagrostis and Solidago cover on diversity indices in the mid‐successional stage. This implies that the early‐successional stage is controlled by the lottery (random) model of community assembly. However, in the mid‐successional stage, the competitive exploitation mechanism is evident, resulting in declines in diversity indices. Thus, the impacts of Calamagrostis and Solidago on diversity indices are evident in the mid‐successional stage.

Diversity and Functional Roles of Root-Associated Endophytic Fungi in Two Dominant Pioneer Trees Reclaimed from a Metal Mine Slag Heap in Southwest China

The utilization of fast-growing, economically valuable woody plants with strong stress resistance, such as poplar and willow, to revegetate severely metal-contaminated mine tailings not only offers a productive and profitable use of abandoned polluted soil resources but also facilitates the phytoremediation of these polluted soils. This study examines the diversity and functional roles of endophytic fungi naturally colonizing the roots of an artificially established Populus yunnanensis forest and the naturally reclaimed pioneer species Coriaria sinica on an abandoned tailing dam in southwest China. Culture-independent analyses revealed that the root systems of both plant species were abundantly colonized by arbuscular mycorrhizal fungi and endophytic fungi, forming rich and diverse endophytic fungal communities predominantly represented by the genera Ilyonectria, Tetracladium, Auricularia, and unclassified members of Helotiales. However, the composition of root endophytic fungal communities differed significantly between the two plant species. Using a culture-dependent approach, a total of 192 culturable endophytic fungal strains were isolated from the roots. The dominant genera included Cadophora, Cladosporium, Cyphellophora, and Paraphoma, most of which were previously identified as dark septate endophytes (DSE). Six representative DSE strains were selected for further study, and significant cadmium tolerance and various plant growth-promoting traits were observed, including the solubilization of insoluble inorganic and organic phosphorus, indole-3-acetic acid (IAA) production, and siderophore synthesis. In greenhouse experiments, inoculating two DSE strains mitigated the inhibitory effects of metal-polluted tailing soil on the growth of P. yunnanensis. This was achieved by reducing heavy metal uptake in roots and limiting metal translocation to the above-ground tissues, thereby promoting plant growth and adaptability. Our findings suggest that as plants reclaim metal-polluted tailings, root-associated endophytic fungal communities also undergo natural succession, playing a critical role in enhancing the host plant’s tolerance to stress. Therefore, these restored root-associated fungi, particularly DSE, are essential functional components of the root systems in plants used for tailing reclamation.

Closing the gap: examining the impact of source habitat proximity on plant and soil microbial communities in post-mining spoil heap succession.

Revegetation of barren substrates is often determined by the composition and distance of the nearest plant community, serving as a source of colonizing propagules. Whether such dispersal effect can be observed during the development of soil microbial communities, is not clear. In this study, we aimed to elucidate which factors structure plant and soil bacterial and fungal communities during primary succession on a limestone quarry spoil heap, focusing on the effect of distance to the adjoining xerophilous grassland. We established a grid of 35 plots covering three successional stages - initial barren substrate, early successional community and late successional grassland ecosystem, the latter serving as the primary source of soil colonization. On these plots, we performed vegetation surveys of plant community composition and collected soil cores to analyze soil chemical properties and bacterial and fungal community composition. The composition of early successional plant community was significantly affected by the proximity of the source late successional community, however, the effect weakened when the distance exceeded 20 m. Early successional microbial communities were structured mainly by the local plant community composition and soil chemical properties, with minimal contribution of the source community proximity. These results show that on small spatial scales, species migration is an important determinant of plant community composition during primary succession while the establishment of soil microbial communities is not limited by dispersal and is primarily driven by local biotic and abiotic conditions.

Composition of Gases in the Interporous Space of Technogenic Bodies

Abstract —We present results of studies of inclusions in secondary sulfates (antlerite and a mixture of copiapite and coquimbite) and arsenates (erythrite and picropharmacolite) formed on the surface of technogenic bodies, such as stored waste from the enrichment of sulfide (Belovo and Ursk waste heaps) and arsenide (disposal maps of the Tuvakobalt plant) ores. A wide range of components were identified in the gas–liquid inclusions, the main ones being water and carbon dioxide. Hydrocarbons, oxygen-containing organic compounds, and nitrogen- and sulfur-containing gases were found in smaller but measurable amounts. Arsine H3As was also detected in inclusions in picropharmacolite (calcium and magnesium arsenate–arsenite). The gas–liquid inclusions in secondary minerals reflect the composition of the interporous space in the waste body, filled with particular atmospheric gases entering the body in free form and with seasonal precipitation. The combination of in situ generated and penetrating gases determines the diversity of inorganic and biotic interactions in technogenic bodies. The presence of hydrocarbons and oxygen-containing organic compounds is, most likely, associated with bacterial transformations of organic matter (residual vegetation, wood, microalgae, and fungi). At the same time, carbon disulfide and sulfur dioxide are indicators of active inorganic reactions of decomposition of the sulfide matrix.

Temporal changes of soil characteristics on Lítov spoil heap, Czech Republic

Temporal changes of soil characteristics on Lítov spoil heap, Czech Republic

Population re-establishment and spatial dynamics of crowberry (Empetrum nigrum ssp. hermaphroditum), a foundation species in restored alpine ecosystems.

Many ecosystems are defined and shaped by one or a few common, foundation species. Even though such species hold a key role in the restoration of these ecosystems, the demographic processes involved in their re-establishment have rarely been studied. Foundation species' population dynamics, re-establishment history, and the abiotic and biotic factors that affect individual establishment at restored sites can be studied by addressing population spatial patterns and age structure. Such an approach to studying population dynamics is particularly relevant for long-lived species with low mortality, such as shrubs in alpine areas. We studied a population of the foundation species Empetrum nigrum ssp. hermaphroditum at an alpine spoil heap site and found evidence of population re-establishment starting within a decade after construction. High Empetrum densities close to the spoil heap edges indicated that short distances to seed sources in the surroundings had a strong positive effect on establishment of individuals. Empetrum individuals were significantly clustered, which indicated intraspecific facilitation. As revealed by spatial analyses of recruits and older, established individuals, clustering developed gradually over time, which indicated a shift from no interaction to increased facilitation. We conclude that intraspecific facilitation promotes Empetrum reestablishment at the studied alpine spoil heap. Synthesis: We show that population spatial patterns and age structure can be successfully used to unveil the re-establishment history of a foundation species in a restoration context. Efficient seed dispersal and intraspecific facilitation seem to be important factors behind Empetrum's successful re-establishment at alpine spoil heaps. Identification of abiotic and biotic factors determining foundation species' establishment success at restored sites can support planning and improve success of restoration.

The Application of Converter Sludge and Slag to Produce Ecological Cement Mortars.

The paper presents an analysis of the effective use of a mixture of steel sludge (S1) and slag (S2) from the converter process of steel production for the production of cement mortars. Metallurgical waste used in the research, which is currently deposited in waste landfills and heaps near plants, posing a threat to groundwater (possibility of leaching metal ions present in the waste), was used as a substitute for natural sand in the range of 0-20% by weight of cement (each). The obtained test results and their numerical analysis made it possible to determine the conditions for replacing part of the sand in cement mortars with a mixture of sludge and slag from a basic oxygen furnace (BOF) and to determine the effects of such modification. For the numerical analysis, a full quadratic Response Surface Model (RSM) was utilized for two controlled factors. This model was subsequently optimized through backward stepwise regression, ensuring the inclusion of only statistically significant components and verifying the consistency of residual distribution with the normal distribution (tested via Ryan-Joiner's test, p > 0.1). The designated material models are helpful in designing ecological cement mortars using difficult-to-recycle waste (i.e., sludge and converter slag), which is important for a circular economy. Mortars modified with a mixture of metallurgical waste (up to 20% each) are characterized by a slightly lower consistency, compressive and flexural strength, and water absorption. However, they show a lower decrease in mechanical strength after the freezing-thawing process (frost resistance) compared to control mortars. Mortars modified with metallurgical waste do not have a negative impact on the environment in terms of leaching heavy metal ions. The use of a mixture of sludge and steel slag in the amount of 40% (slag/sludge in a 20/20 ratio) allows you to save 200 kg of sand when producing 1 m3 of cement mortar (cost reduction by approx. EUR 5.1/Mg) and will also reduce the costs of the environmental fee for depositing waste.