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This paper deals with the potential reuse of coal mine waste rocks (CMWR) as an alternative material for road construction to conserve the natural resources and sustainable management of mining waste. The investigation was conducted through the determination of the chemical, mineralogical, geotechnical properties, and acid mine drainage formulation of CMWR as well as economic feasibility. This waste was used either alone for embankments and mixed with stabilizing agents fly ash (FA) and hydraulic road binder (HRB) for pavement applications. The experimental results confirmed that weathered CMWR can be successfully used alone as a sustainable alternative material for the embankment. Furthermore, the use of stabilizing agents in the following ratio CMWR:FA:HRB = 80:20:5 allow the use of CMWR in road sub-base layers for high-traffic pavements. Also, the environmental investigations showed that CMWR does not present any potential contaminating risk on the surrounding environment and most of the pyrite particles were already oxidized. Therefore, the environmental impact of acid mine drainage produced by pyritic waste throughout its life cycle can be neglected. Finally, an economic case study confirmed the workability of CMWR reuse in a radius of 29 km around their dumps by resulting in a lower cost compared with conventional materials.

The linear economy follows the “take-make-dispose” model and generates huge amounts of waste without consideration for recycling or reuse. This model which deals with raw materials puts pressure on natural resources and creates a serious environmental impact. In a circular economy, the “reduce-reuse-recycle” model is applied to recycle waste into resources and reduce the impact on the environment and society. This work aims to highlight the significance of implementing a circular economy approach in the construction sector by merging two different production lines, notably mining activity and agri-food industry. The investigation presents sustainable management of coal mine waste (CMW) and olive pomace (OP) in the production of eco-friendly fired materials and introduces an innovative approach for manufacturing lightweight fired bricks. Microstructural, physical, mechanical, and thermal properties were determined to evaluate the technological quality of fired materials at 900 °C. As a pore-forming agent, adding 10 wt% OP yielded specimens with a bulk density of 1552 kg/m3, water absorption of 19.80%, apparent porosity of 29.61%, loss on ignition of 26.98%, and compressive strength of 7.08 MPa, satisfying standards for clay masonry units. Simultaneously, it enhances the thermal insulation by reducing thermal conductivity by 18% compared to the control sample with CMW. In this regard, the transition to a greener construction sector necessitates the immediate implementation of a circular economy approach to developing eco-friendly building materials by recovering large amounts of industrial waste, limiting the overuse of natural resources (e.g., clays), and improving the engineering properties of the final product.

Waste rocks (WRs) from a lignite-producing coalfield and fly ash (FA) produced from the same lignite have been investigated in this study with a primary objective to determine the potential for co-disposal of WRs and FA to reduce the environmental contamination. Mixing WRs with FA and covering WRs with FA have been investigated. Particle size effect caused ≤2 mm particles to produce low pH (~2) and metal-laden leachates, indicating higher sulphide minerals’ reactivity compared to larger particles (≤10 mm, pH ~ 4). Co-disposal of FA as mixture showed an instantaneous effect, resulting in higher pH (~3–6) and better leachate quality. However, acidity produced by secondary mineralisation caused stabilisation of pH at around 4.5–5. In contrast, the pH of the leachates from the cover method gradually increased from strongly acidic (pH ~ 2) to mildly acidic (pH ~ 4–5) and circumneutral (pH ~ 7) along with a decrease in EC and elemental leaching. Gradually increasing pH can be attributed to the cover effect, which reduces the oxygen diffusion, thus sulphide oxidation. FA cover achieved the pH necessary for secondary mineralisation during the leaching experiment. The co-disposal of FA as cover and/or mixture possesses the potential for neutralisation and/or slowing down AMD and improving leachate quality.

The shortage of investment areas may be at least partially satisfied by the development of reclaimed post-mining areas. These are often subsidence zones levelled with hard coal mine waste or reclaimed sub-level old dumps of this waste. From the geotechnical point of view, such grounds represent anthropogenic grounds containing mine waste, and they are considered as possessing unfavourable properties in terms of the foundation of building structures. The paper initially presents the analysis of the properties of waste from the hard coal mining industry, emphasising that they expose several beneficial properties enabling their safe use. The second part of the article is devoted to the determination of soil density using the DPSH probe. It has been found that the applicable standards lack complex relationships that would allow for a reliable interpretation of the measurement results in a wide range of soil types. The last part presents exemplary results of measurements made with the DPSH probe at a construction site. The obtained results allowed for the formulation of several conclusions regarding the possibility of building on a ground made of hard coal waste and the use of dynamic sounding to assess the geotechnical properties of such anthropogenic soil.

Lignite fly ash (FA) and waste rocks (WRs) were mixed in three different ratios (1:1, 1:3 and 1:5) and studied to compare the effects of adding FA on acid mine drainage generation from coal mining WRs, leachability of elements and the potential occurrence of the secondary minerals. FA mixed with WRs showed significant differences in pH levels compared to previous research. The 1:1 mixture performed best of all the three mixtures in terms of pH and leachability of elements, mainly due to the higher proportion of FA in the mixture. The pH in the 1:1 mixtures varied between 3.3 and 5.1 compared to other mixtures (2.3-3.5). Iron and SO leached considerably less from the 1:1 mixture compared to the others, indicating that the oxidation of sulphides was weaker in this mixture. Aluminium leached to a high degree from all mixtures, with concentrations varying from mg L to g L . The reason behind this increase is probably the addition of FA which, due to acidic conditions and the composition of the FA, increases the availability of Al. For the same reason, high concentrations of Mn and Zn were also measured. Geochemical modelling indicates that the 1:1 mixture performs better in terms of precipitation of Al minerals, whereas Fe minerals precipitated more in mixtures containing less FA. These results suggest that, with time, the pores could possibly be filled with these secondary minerals and sulphate salts (followed by a decrease in sulphide oxidation), improving the pore water pH and decreasing the leachability of elements. Since grain size plays a crucial role in the reactivity of sulphides, there is a risk that the results from the leaching tests may have been influenced by crushing and milling of the WR samples.

Since 2015, a large heap of improperly disposed coal‐mine waste in Ban Chaung, Dawei district, Myanmar, has repeatedly spontaneously combusted, affecting an indigenous community. Recently, the regional Myanmar government has compelled the mine to properly manage the mine waste heap, but there is no opportunity for affected villagers to participate. This study empowers the affected villagers to make risk management decisions via a community citizen science approach. First, field investigations were performed with the affected community to identify hot spots at the waste heap releasing gaseous pollutants that may exceed acceptable levels. Next, existing monitoring data previously collected by the community were interpreted as clear evidence of past poor waste management. Information about suppression of existing fire and mine waste storage options was presented to the community for them to make an informed decision about the most appropriate corrective action that should be taken by the mine. The mining company chose to use surface sealing for both suppression of existing fire and on‐site storage of the mine waste but did not install any long‐term monitoring system. Nevertheless, the community's choice was surface sealing with preventive monitoring together with emergency response, which is the more scientifically appropriate option. This outcome of a science‐based risk management decision by the community will be forwarded to the regional government for enforcement. This process of community citizen science is in line with the normative rationale of public participation, which is meant to influence decisions, elevate democratic capacity, and empower marginalized individuals and communities. Key Points Spontaneously combusting coal‐mine waste is adversely affecting an indigenous community in Myanmar since 2015 Community citizen science allowed the affected villagers to make a decision about the most appropriate corrective action The community's choice of surface sealing with preventive monitoring is more scientifically appropriate than the mine's choice

Coal mine waste rock is generated during coal extraction and is usually disposed of in non-engineered dumps. The dumps are extended vertically to 100–120 m height to reduce the spatial footprint. The waste mass generally consists of loose, cohesionless material associated with high heterogeneity, so the dumps are prone to slope failures. A typical dump configuration in Jharkhand, India (total height, H  = 125 m; slope angle, θ  = 3 V :1 H ) is considered for evaluation in this study. A 2D limit equilibrium numerical analysis is performed to estimate the slope stability. A parametric study is conducted to understand the effect of bench height ( H ), bench width ( W ), and slope angle ( θ ) on the factor of safety. The heterogeneity of the material is analyzed using the probabilistic descriptors (mean, standard deviation, and coefficient of variation ( CoV )). The influence of CoV on the shear strength parameters is studied at various intervals ranging from 10 to 80% and compared using Monte Carlo simulation and alternative point estimate methods. Further, the modified slope geometry and the benches are recommended as remediation methods to achieve the desired safety factor. The results provide valuable insights into understanding the influence of slope geometry and material heterogeneity during the stability analysis of coal mine dumps.

Coal mining waste in the form of coal gangue (CG) was established recently as a potential fill material in earthworks. To ascertain this potential, this study forecasts the strength and California Bearing Ratio (CBR) characteristics of chemically stabilized CG by deploying two widely used artificial intelligence approaches, i.e., artificial neural network (ANN) and random forest (RF) regression. In this research work, varied dosage levels of lime (2, 4, and 6%) and gypsum (0.5, 1, and 1.5%) were employed for determining the unconfined compression strength (UCS) and CBR of stabilized CG mixes. An experimental study comprising 384 datasets was conducted and the resulting database was used to develop the ANN and RF regression models. Lime content, gypsum dosage, and 28 d curing period were considered as three input attributes in obtaining three outputs (i.e., UCS, unsoaked CBR, and soaked CBR). While modelling with the ANN technique, different algorithms, hidden layers, and the number of neurons were studied while selecting the optimum model. In the case of RF regression modelling, optimal grid comprising maximal depth of tree, number of trees, confidence, random splits, enabled parallel execution, and guess subset ratio were investigated, alongside the variable number of folds, to obtain the best model. The optimum models obtained using the ANN approach manifested relatively better performance in terms of correlation coefficient values, equaling 0.993, 0.995, and 0.997 for UCS, unsoaked CBR and soaked CBR, respectively. Additionally, the MAE values were observed as 45.98 kPa, 1.41%, and 1.18% for UCS, unsoaked CBR, and soaked CBR, respectively. The models were also validated using 2-stage validation processes. In the first stage of validation of the model (using unseen 30% of the data), it was revealed that reliable performance of the models was attained, whereas in the second stage (parametric analysis), results were achieved which are corroborated with those in existing literature.

Underground mining exploitation in the Upper Silesian Coal Basin results in lowering of a land surface. It has its environmental consequences. These processes favor the creation of wetlands and floodplains, which often help to increase biodiversity. However, progressive lowering of the land surface disrupts flow of rivers, force change of land use, and may lead to real risks for building facilities. Therefore, it is necessary to undertake reclamation works, which consist in filling depression area. All this leads to many environmental problems. The article deals with the problem of liquidation of mining damages, by using post-mining waste. It is based on a case study of a 1.5-kilometer stretch of the Szotkowka valley in Polomia (southern Poland), where the site was lowered and a still-developing floodplain of 21 ha has been created. According to the project, reclamation project will cover liquidation of the floodplain and reconstruction of the riverbed. Work performance will require the deposit of 2.2 million m3 of aggregate in the basin. The use of coal mine waste is planned. Static leaching tests carried out for Environmental Impact Assessment were the basis for recognizing that the material coming from the mines would not pose a threat to the soil and water environment. However, it was omitted that the obtained pollution leaching results were referred to the laboratory sample (90-100 g) only, not to 2.2 million m3 of post - mining waste. The authors reinterpreted the results of the leaching tests, basing on the European standard EN 12457-4 [1]. They obtained results in mg/kg of a dry matter, and then they calculated the potential mass pollution which can be leached from the entire volume of the material which is planned to be used in engineering works. They also took into account the results of the monitoring of underground waters of the mining waste landfill \"Pochwacie\", which is situated opposite to the planned works, on the left bank of the Szotkowka River. The obtained results confirmed, that the negative impact of planned reclamation works on the soil and water environment will be significant. As a consequence, a new source of pollution of underground and surface waters will be created. This aspect has been completely neglected in the environmental impact assessment procedure. As part of the article, the authors also presented formal and legal conditions for using mining waste in the reclamation of the areas of mining damage. The results of the presented analyses made it possible to indicate several guidelines as the authors' proposal, and to introduce them into legal solutions in the scope of using post-mining waste for engineering works.

Salmonella is an important human pathogen and poultry products constitute an important source of human infections. This study investigated prevalence; identified serotypes based on whole genome sequence, described spatial distribution of Salmonella serotypes and predicted risk factors that could influence the prevalence of Salmonella infection in commercial poultry farms in Nigeria. A cross sectional approach was employed to collect 558 pooled shoe socks and dust samples from 165 commercial poultry farms in North West Nigeria. On-farm visitation questionnaires were administered to obtain information on farm management practices in order to assess risk factors for Salmonella prevalence. Salmonella was identified by culture, biotyping, serology and polymerase chain reaction (PCR). PCR confirmed isolates were paired-end Illumina- sequenced. Following de novo genome assembly, draft genomes were used to obtain serotypes by SeqSero2 and SISTR pipeline and sequence types by SISTR and Enterobase. Risk factor analysis was performed using the logit model. A farm prevalence of 47.9% (CI95 [40.3-55.5]) for Salmonella was observed, with a sample level prevalence of 15.9% (CI95 [12.9-18.9]). Twenty-three different serotypes were identified, with S. Kentucky and S. Isangi as the most prevalent (32.9% and 11%). Serotypes showed some geographic variation. Salmonella detection was strongly associated with disposal of poultry waste and with presence of other livestock on the farm. Salmonella was commonly detected on commercial poultry farms in North West Nigeria and S. Kentucky was found to be ubiquitous in the farms.