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The 6th coal seam floor of Tangjiahui Coal Mine is seriously threatened by Ordovician karst water. It is the mine with the deepest mining depth and the highest water pressure in Zhungeer Coal Field. In order to eliminate the threat of water damage from Ordovician floor, the ground area treatment test project was carried out on the 61207 working face of Tangjiahui Mine. The test results show that there are many leakage and return phenomena during the directional drilling process, the grout is large in the grouting project, the efficiency of drilling and grouting is low, and the 61207 working face adopts the ground area treatment method to prevent and control the floor Ordovician water damage. The construction period is long, and it is difficult to meet the needs of continuous cost control of the face production. Through comprehensive comparative analysis, it is advisable to adopt the technical route of water prevention and control, which is the combination of “bottom exploration and reinforcement by directional drilling inside working face” and “treatment of fault zone by directional drilling outside working face”.

In order to study the interaction of organic matter with arsenic (As) and lead (Pb) in natural water, standard dissolved organic matter (standard DOM) was taken as the research object, and the analysis was carried out by spectroscopy, high-resolution mass spectrometry, parallel factor analysis and other methods. The results showed that compared with fulvic acids and humus, protein-like tyrosines showed higher binding capacity to As and Pb. The results of high-resolution mass spectrometry showed that heavy metals could change the original characteristics of the standard DOM, resulting in the transformation of organic matter, such as the decrease of amino carbohydrate components, the increase of tannin-like components, the decrease of the relative abundance of CHO, and the increase of the relative abundance of other heteroatoms. DOM-As showed that there was a strong positive correlation between the ultraviolet characteristic parameter a254 and the fluorescence characteristic parameter HIX, the amino sugar component and CHO obtained by ultra-high resolution mass spectrometry were positively correlated with the ultraviolet characteristic parameters a254, a260, a280 and the fluorescence characteristic parameter HIX, and the fluorescence component C1 was positively correlated with the unsaturated hydrocarbon component obtained by mass spectrometry. The results of the study may provide theoretical support for the quantitative assessment of the mechanism of organic matter-heavy metal interactions in water bodies, thereby reducing the environmental behavior of various pollutants such as heavy metals. [ABSTRACT FROM AUTHOR]

Long-term coal mining activities have led to severe heavy metal pollution in the soil environment of coal mining areas, posing significant threats to both ecological environments and human health. In this study, surface soil samples were collected from the overlying soil of coal gangue and the surrounding areas of the Panyi coal mine in Huainan. The concentrations of Cd, Zn, Cu, Ni, and Pb elements were determined. A self-organizing map (SOM) and an absolute principal component score multiple linear regression (APCS-MLR) receptor model were employed for the quantitative analysis of the soil's heavy metal pollution sources and contributions. Additionally, this study focused on the analysis of the pathways of the relatively serious pollution of Cd. The results revealed that the average concentrations of heavy metals (Cd, Pb, Zn, Cu, Cr, and Ni) in the study area were 4.55, 0.59, 1.54, 0.69, 0.59, and 0.71 times the local soil background values, respectively. The concentrations of Cd and Zn exceeded the risk screening values at some sampling points, with exceedance rates of 44% and 8%, respectively, indicating a relatively serious Cd contamination. The sources of heavy metals in the soil in the study area were classified into four categories: mining activities, agricultural activities, weathering of natural matrices, and other unknown sources, with average contributions of 55.48 percent, 24.44 percent, 8.91 percent and 11.86 percent, respectively. Based on the spatial distribution of Cd, it was inferred that atmospheric deposition is one of the important pollution pathways of Cd in the study area. Cd profile distribution patterns and a surface water pollution survey showed that the farmland areas were affected by the irrigation water pathway to some extent. The vertical distribution of heavy metal content in the forest area showed a strong disorder, which was related to the absorption function of plant roots. The results of this study can help to improve the environmental management of heavy metal pollution so as to protect the ecological environment and human health. [ABSTRACT FROM AUTHOR]

East China is a highly aggregated coal–grain composite area where coal mining and agricultural production activities are both flourishing. At present, the geochemical characteristics of dissolved inorganic carbon (DIC) in groundwater in coal mining areas are still unclear. This study combined hydrochemical and carbon isotope methods to explore the sources and factors influencing DIC in the groundwater of different active areas in coal mining areas. Moreover, the 13C isotope method was used to calculate the contribution rates of various sources to DIC in groundwater. The results showed that the hydrochemical types of groundwater were HCO3-Ca·Na and HCO3-Na. The main water‒rock interactions were silicate and carbonate rock weathering. Agricultural areas were mainly affected by the participation of HNO3 produced by chemical fertilizer in the weathering of carbonate rocks. Soil CO2 and carbonate rock weathering were the major sources of DIC in the groundwater. Groundwater in residential areas was primarily affected by CO2 from the degradation of organic matter from anthropogenic inputs. Sulfate produced by gypsum dissolution, coal gangue accumulation leaching and mine drainage participated in carbonate weathering under acidic conditions, which was an important factor controlling the DIC and isotopic composition of groundwater in coal production areas. The contribution rates of groundwater carbonate weathering to groundwater DIC in agricultural areas and coal production areas ranged from 57.46 to 66.18% and from 54.29 to 62.16%, respectively. In residential areas, the contribution rates of soil CO2 to groundwater DIC ranged from 51.48 to 61.84%. The results will help clarify the sources and circulation of DIC in groundwater under the influence of anthropogenic activities and provide a theoretical reference for water resource management. [ABSTRACT FROM AUTHOR]

Sulfate ions are commonly found in water, but excessive concentrations of these ions can have detrimental effects on the aquatic environment. In this study, reed straw was chosen as the raw material for producing biochar, which was then pyrolyzed with coal gangue to create environmentally friendly adsorption materials. This innovative approach aims to combat the issue of elevated SO42− concentrations in water while efficiently utilizing solid waste. The results showed that the adsorption process best fit the when the was pH 2 and the dosage was 8 g·L−1, and the adsorption capacity reached the maximum of 49.56 mg·g−1. Via extensive characterization, kinetic studies, and isotherm experiments on the modified biochar, we determined that the mechanism of SO42− adsorption primarily involves electrostatic adsorption, physical adsorption, and chemical adsorption. The toxicology experiments showed that the activity of antioxidant enzymes and the amount of malondialdehyde decreased, and the content of chlorophyll and soluble protein increased. These findings suggest that modified biochar can mitigate the harmful effects of SO42− on reeds to a certain extent, ultimately promoting the growth of these plants. [ABSTRACT FROM AUTHOR]