Evolution of Water Hazard Control Technology in China’s Coal Mines

Mine Water and the Environment - We analyzed the regional nature of China’s coal mine water disasters based on three aspects: the main water source, water-conducting passages, and threat...     

The Effects of Caving of a Coal Mine’s Immediate Roof on Floor Strata Failure and Water Inrush

Large scale roof strata caving that occurs during coal extraction can irreversibly damage floor strata and result in riskier mining operations. Four research models incorporating floor water pressure were assessed for floor strata failure, using eight methods and two classification systems. A connection between floor strata failure and the coefficient of impact risk was developed. The derived equations represent a potentially effective method for providing a preliminary assessment of the risks associated with floor strata failure due to caving. A classification system of floor failure potential can be constructed to minimize risks during mining.     

Water–Sediment Two-Phase Flow Inrush Hazard in Rock Fractures of Overburden Strata During Coal Mining

Mine Water and the Environment - To investigate the mechanism of water–sediment inrush during coal mining, the characteristics of water–sediment flow in rock fractures were...     

Coal fires in China

Coal fires have a very long history in China; the oldest coal fires have being burning for many million years. Up to now more than 56 coal fires spots were distinguished. They mainly locate in West-North of China, North of China and East-North of China. About millions of tons of coal have been burned in fires every year. Xinjiang Autonomy is the most serious region in coal fires as it has 38 coal fires spots and about 6.85 million tons of coal was burned every year. Coal fires in China ignited by wildfires,spontaneous combustion and human being during mining activities. These fires have released about 0.9 million tons of gasses (including CO, CO2, SO2, NO2 CH4, CO2, H2S etc.) into the atmosphere every year, most of which are brought to the east by wind and resulting more heavier air pollution in northern China.     

Dynamic Characteristics of Water Inflow from a Coal Mine’s Roof Aquifer

The static and dynamic inflow of water from the roof aquifer changes as mining progresses. We used a second-order dynamic model to describe the water inflow process. The parameters of the water inflow model were solved using actual drainage from roof aquifers at nine working faces in the Yuanyanghu mining area of the Ningxia Autonomous Region, China, as well as the peak water inflow values, their locations, the equilibrium values of water inflow, and their initial occurrence locations. The parameters of the second-order dynamic model of water inflow were inversely calculated. The peak values of water inflow without drainage were also calculated. The results indicate that pre-drainage of roof water significantly weakens the intensity of water inflow during the mining process, reducing peak values by more than 72%. The characteristics of the water-conducting fractured zones determine the major drainage locations, while the water-rich and water-conductive nature of the direct discharge aquifer affects the water inflow equilibrium values and initial occurrence positions. The results show that the model parameters and characteristic values of water inflow are determined by the hydrogeological nature of the roof strata, water-conducting fractured zone(s), and mining speed.

     

Effluent Water Quality at Phosphate Mines in M’Dhilla,Tunisia and its Potential Environmental Effects

The physicochemical characteristics of effluent water produced by phosphate mining and processing in M’dhilla, Tunisia, its potential environmental effects, and its suitability for irrigation were studied. Five effluent water samples were collected from the M’dhilla phosphate plant and analyzed for selected parameters, including chemical and biochemical oxygen demand, metals, sulfate, and chloride. Most of the contaminant concentrations exceeded international water quality standards. Water treatment is recommended for all effluents in the M’Dhilla industrial area to improve received water quality. The potential adverse environmental effects and human health risks associated with the discharge of phosphate mining wastewater are also discussed.     

Mechanism of Water Inrush Through Fault Zones Using a Coupled Fluid–solid Numerical Model: A Case Study in the Beiyangzhuang Coal Mine,Northern China

Mine Water and the Environment - To better understand the mechanism of water inrush from fault zones, we investigated a typical inrush case from a coal mine in northern China, identified the water...     

Detection of Abandoned Coal Mine Goaf in China’s Ordos Basin Using the Transient Electromagnetic Method

Mine Water and the Environment - Early coal mining and management methods left a large number of unknown goafs in China’s important Ordos Basin, which has restricted the safe production in...     

China′s Agenda 21 and the Development of the Coal Industry

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Surface Soil Water Content Before and After Coal Mining and its Influencing Factors—A Case Study of the Daliuta Coal Mine in Shaanxi Province,China

The spatial variability in soil water content in the Daliuta mining area in western China was studied before and after coal mining using ground penetrating radar and geostatistical methods. The relationships among soil water content, soil physical properties, topographical factors, and vegetation density were analysed using classical statistics. The average surface soil water content changed slightly between the two detection events at the centre of the subsidence, from 0.084 cm³/cm³ to 0.079 cm³/cm³; there, the distribution of the soil water content was more closely related to terrain than any of the other factors being considered. Along the subsidence boundary, the surface soil water content decreased significantly after mining, from 0.099 cm³/cm³ to 0.083 cm³/cm³ at one location. The total soil porosity, soil organic matter, and soil clay content were positively correlated with soil water content before mining. However, after mining, the relationship between total soil porosity and soil water content significantly strengthened while the relationships between other soil physical and chemical properties and soil water content weakened. Vegetation was determined to be the main factor controlling the surface soil water content before and after coal mining at one location in a small (1,600 m²) area of the subsidence boundary.

     

An Analog Model Study on Water–Sand Mixture Inrush Mechanisms During the Mining of Shallow Coal Seams

Water–sand mixture inrushes into shallow underground workings have caused casualties and property loss. A coupled fluid–solid analog model was developed to simulate the water–sand mixture inrush processes during mining from fracture production and development, based on the hydrogeological conditions at the #22304 working face of the Shigetai coal mine in the Erdos coal basin of northeast China. The deformation characteristics of the overlying strata and water pressure variations within the water-flowing fractured zone were monitored and analyzed. The results show that the water–sand mixture inrush consists of three stages: development of cracks in the overlying strata, initiation of a water inrush channel, and evolution of the inrush channel. The stresses of the overlying strata, water pressures, and permeability characteristics of water and sand inrush pathways change within the three stages. These findings lay a solid foundation for predicting water–sand mixture inrushes in shallow coal mines.

     

General Thoughts on the Reform and Development of China′s Coal Industry

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Monitoring Acid Mine Drainage’s Effects on Surface Water in the Kizel Coal Basin with Sentinel-2 Satellite Images

Mine Water and the Environment - Mining in the Kizel coal basin (Perm Region, Russia) ceased 20 years ago; however, AMD with high levels of total iron (Fetotal) and trace elements still affects the...     

Effects of Coalbed Methane Co-produced Water for Irrigation in China’s Qinshui Basin: An Experimental Field Study

The management of coalbed methane (CBM) co-produced waters (hereafter refer to as produced water) has broad effects on the native plants and soils in the Qinshui Basin of China and has become a high priority over the past decade. To investigate the short-term effects of produced water on crop production and soil health, a field study was conducted in the Shizhuang Block, which is one of the most active CBM-producing areas in the Qinshui Basin. Spring maize was grown during 2015 under the following flood irrigation treatments: freshwater (as a control), and three produced water sub-treatments with electrical conductivity (EC) values of 1.9?±?0.9, 2.3?±?0.5, and 3.4?±?1.1 ds/m. The SAR concentration of the produced water ranged from 17.62 to 44.45 meq/L; the excessive SAR content makes the water unsuitable for direct irrigation without amendment. The pH, SAR, and constituent concentration of soil samples and crop yield were tested before planting and after harvest, while the soil moisture and plant height were measured monthly from June to October. The growth parameters indicated that salinity decreased total crop yield and individual plant height. The monitored soil indexes showed that the SAR content at a depth of 20 cm (top soil) exceeded that at 40 cm, and increased as the EC of the irrigation source increased at both depths. However, there were no obvious differences in pH or chemical composition of the soil samples, all being less than the Republic of China’s soil pollution standards. Soil moisture was determined more by the monsoon climate than by changes in the soils’ hydraulic properties.     

Mine Water Literature in ISI’s Science Citation Index Expanded™

Abstract.   Scientists in most countries are assessed by the number of papers published in journals that are cited in the Science Citation index. This article reviews the mine water related entries in the Science Citation Index Expanded and discusses the results. Mine water relevant literature is spread over more than 900 journals, with 13 of them accounting for 25% of all relevant papers. No journal focused on mine water relevant issues can be found in the Index.     

China’s Relationship with IMWA

Mine Water and the Environment -     

Considerations of the Development of China’s Coal Technology during 9th Five－Year Plan Period

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Developing Clean Coal Technologies in Conformity with Chinese Characteristics of Coal Development and Utilization

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