Effects of Coal Mining Subsided Water Area on Temperature Change in Huaibei Coal Mine

[Objective] The study aimed to discuss the effects of coal mining subsided water area on temperature change in Huaibei coal mine. [Method] Based on the data of monthly temperature from 1957 to 2007 recorded by Suixi （coal mining subsided water area） and Fuyang stations （control）, the effects of coal mining subsided water area on temperature change in Huaibei coal mine were discussed using linear trend estimation and comparative analysis methods. [Result] Spring, autumn, winter and annual average temperatures of coal mining subsided water area （Suixi） were increased in the last 51 years, and the increase of winter temperature was mostly significant with a tendency rate of 0.49 ℃/10 a. Meanwhile, annual temperature range of coal mining subsided water area was decreased from 1957 to 2007. Temperatures of Suixi in four seasons were lower than those of Fuyang from the 1960s to 1990s, and temperatures of coal mining subsided water area （Suixi） were higher than those of Fuyang in spring, autumn and winter but lower than those of Fuyang in summer from 2000 to 2007. [ Result] Coal mining subsided water area had certain effects on temperature change of Huaibei coal mine.

Optimum location of surface wells for remote pressure relief coalbed methane drainage in mining areas

Based on engineering tests in the Huainan coal mining area,we studied alternative well location to improve the performance of surface wells for remote pressure relief of coalbed methane in mining areas.The key factors,affecting location and well gas production were analyzed by simulation tests for similar material.The exploitation results indicate that wells located in various positions on panels could achieve relatively better gas production in regions with thin Cenozoic layers,low mining heights and slow rate of longwall advancement,but their periods of gas production lasted less than 230 days,as opposed to wells in regions with thick Cenozoic layers,greater mining heights and fast rates of longwall advancement.Wells near panel margins achieved relatively better gas production and lasted longer than centerline wells.The rules of development of mining fractures in strata over panels control gas production of surface wells.Mining fractures located in areas determined by lines of compaction and the effect of mining are well developed and can be maintained for long periods of time.Placing the well at the end of panels and on the updip return airway side of panels,determined by lines of compaction and the effect of mining,would result in surface wells for remote pressure relief CBM obtaining their longest gas production periods and highest cumulative gas production.

Soil Heavy Metal Pollution and Health Risk Assessment of Abandoned Land in Coal Mining Areas in Xingren County

Total contents of heavy metals （ Pb, Cr, Cd, Hg, As, Cu, Zn, and Ni） in 68 soil samples were determined to evaluate the contamination level of soil from five coal mine areas in Xingren County, Guizhou province. The pollution levels of heavy metals were characterized by anthro- pogenic influence multiple, and the pollution of heavy metal in soil was evaluated using geo-accumulation index. Based on the health risk models recommended by the U.S. Environmental Protection Agency （ US EPA）, the health risks of heavy metals in the soils were assessed. The results showed that the abandoned land in the five coal mining areas were contaminated by heavy metals, and the order of pollution levels of eight heavy metals was As 〉 Pb 〉 Cu 〉 Hg 〉 Ni 〉 Cr 〉 Cd 〉 Zn. The soils suffered moderate-heavy pollution from As and Pb, and the contents of As and Pb in the soils were 13.16 and 4.76 times higher than the background values of Guizhou Province, followed by Cu, Hg and Ni , while soil pollution from Cr, Cd and Zn was mild. The order of non-caminogenic risks of the heavy metals in the soils was As 〉 Pb 〉 Cr 〉 Ni 〉 Cu 〉 Hg 〉 Cd 〉 Zn, and the non-carcinogenic dsk value of As was higher than that its threshold value 1, which indicated that As had a high potential health risk to adults and children. The order of carcinogen risks of the four heavy metals was As 〉 Cd 〉 Cr 〉 Ni, and the carcinogenic risk value of As was higher than its threshold value, indicating that As had a high carcinogenic risk to adults and children. The carcinogenic risk values of other three heavy metals （ Cd, Cr and Ni） were lower than the threshold value, so they had no carcinogenic risk to human health. Moreover, children were more sensitively affect- ed by heavy metals from the abandoned land. Therefore, the health of children in such areas should be paid more attention to. The HI value of the eight heavy metals to children was seven times higher than that to adults. The contribution rate of HQAs to HI was about 88%, and the contribution rate of CRA, to TCR was about 98%, so As was the most crucial factor influencing non-carcinogenic and carcinogenic dsk in the abandoned soils.

A Synergetic Study on Large-Scale Coal Mining and Eco-Environment Protection in Shendong Coal Mining Area

Based on the sharp contradiction between the economic benefits and adverse ecological impact of coal development in China's west,this paper establishes an evaluation model for the synergetic eco-environmental development in Shendong Coal Mining Area through using synergism of five laws and the fuzzy comprehensive evaluation method. The analysis on synergy between large-scale coal mining and the eco-environment protection in Shendong is also conducted,arriving at the conclusion that synergetics of Shendong 's eco-environment protection is"good". And thus,the result sheds light on the fact that while working to quench China's energy demand on its path towards a modernized large coal mine complex,Shendong,as part of Shenhua Group's mining operation,has applied innovative management concepts and models to improve eco-environment for harmony and win-win results between resource exploration and environmental protection.

Impact of coal mining on groundwater of Luohe Formation in Binchang mining area

Groundwater of Luohe Formation is the main water source for industrial and agricultural and residential use in Binchang mining area,which is one of the key elements to water conservation coal mining.However,few studies are available to document the enrichment characteristics and influence of underground coal mining on groundwater for the Luohe Formation.This study evaluates the changes of groundwater levels and spring flow caused by mining activities to explore the influence mechanism of coal mining on groundwater by comparatively analysing existing mining data and survey data combined with a series of mapping methods.The results show that the aquifer of Luohe Formation are gradually thinning south-eastwards,disappeared at the mining boundary.In the vertical direction,the lithological structure is distinct,due to alternative sedimentation of meandering river facies and braided river facies.According to the yielding property,the aquifer is divided into three sections,namely,strong water-rich section,medium water-rich section,and weak water-rich section,which are located in northwest and central part,southwest,and the rest part of the mining area,respectively.Mining of Tingnan Coal Mine since 2004 has caused a 3.16 to 194.87 meters drop in groundwater level of Luohe Formation.Until 2015,70.10%of the mining area undergoes a groundwater level drop larger than 10.00 meters.Another influence of underground mining is that the total flow from 34 springs in 8 southern coal mines of the area has decreased by 286.48 L/s with a rate of decrease at 46.95%from 2007 to 2017.The areas that groundwater level falls or spring flow declines are manly located in the mine gob areas.Results also indicate that the ratio of the height of water conducted fracture zone to the mining height in Binchang mining area is between 16.85 and 27.92.This may increase ground water flow in vertical direction,causing a water level in the aquifer system to drop and ultimately decreasing the flow from the springs.The research results will provide data and theoretical support for the protection of groundwater resources and water conservation coal mining of Luohe Formation in Binchang mining area.

Monte-Carlo Method for Coalbed Methane Resource Assessment in Key Coal Mining Areas of China

Monte-Carlo method is used for estimating coalbed methane （CBM） resources in key coal mining areas of China. Monte-Carlo method is shown to be superior to the traditional volumetric method with constant parameters in the calculation of CBM resources. The focus of the article is to introduce the main algorithm and the realization of functions estimated by Monte-Carlo method, including selection of parameters, determination of distribution function, generation of pseudo-random numbers, and evaluation of the parameters corresponding to pseudo-random numbers. A specified software on the basis of Monte-Carlo method is developed using Visual C＋＋ for the assessment of the CBM resources. A case study shows that calculation results using Monte-Carlo method have smaller error range in comparison with those using volumetric method.

A New Discovery on the Deformation Behavior of Shale Gas Reservoirs Affecting Pore Morphology in the Juhugeng Coal Mining Area of Qinghai Province, Northwest China

Objective The Juhugeng mining area in Qinghai Province of northwest China has attracted wide attention among geologists for it hosts typical coal measure gases.The shale gas reservoirs were reformed by intensive structural movements during geological periods,

Soil heavy metal(loid)s and risk assessment in vicinity of a coal mining area from southwest Guizhou, China

Total concentrations of arsenic, lead, cadmium, mercury, nickel, chromium, and copper in the soils from near a coal mine area in southwest Guizhou, China, were measured to evaluate the level of contamination, and the potential ecological risks posed by the heavy metals were quantitatively estimated. Results reveal that all heavy metals/metalloid exceeded the background values for soil environmental quality of heavy metals in Guizhou area. Geo-accumulation index(I_(geo)) showed that arsenic had the highest contamination level(I_(geo)=4) among the seven heavy metals/metalloid, and the contamination levels of mercury and lead were also relatively high(I_(geo)=3). Pearson correlation and cluster analysis identified that mercury, copper and arsenic had a relationship, and their presence might be mainly related to mining activity, coal and oil combustion, and vehicle emissions. Improved Nemerow index indicated that the overall level of heavy metal contamination in the studied area ranged from moderately–heavily contaminated to heavily contaminated level. Potential ecological risk index(R_I) analysis manifested that the whole ecological risk level ranged from high degree to very high degree(325.30≤R_I≤801.02) in the studied soil samples, and the potential ecological risk factors (E_r^i) of heavy metals/metalloid were as follows: Hg > As > Cd > Pb > Cu > Ni > Cr, and the E_r^i of Hg and As reached very high risk grade.

Effect of coal resources development and compensation for damage to cultivated land in mining areas

The exploitation of coal resources inevitably affects, to different degrees, arable land resources and impacts the socio-economic development in mining areas. Therefore it is of great practical importance to probe the rules of the effect from coal resource exploration on arable land. Suitable and effective measures to compensate for damaged to and loss of arable land resources should be taken on the basis of carrying out green mining and reducing damage to limited arable land resources. We have used GIS in simulating the effect of coal resource exploration on arable land. In light of our simulation of the space-time spectrum, the effect is analyzed. Given the socio-economic development conditions of a mining area, specified rational amounts and opportunities for compensation to arable land in mining areas are explored. Finally, from a policy perspective, relevant proposals for rational arable land resource compensation are proposed to facilitate the coordinated development between coal resource exploitation and socio-economy development in mining areas.

Exploitation technology of pressure relief coalbed methane in vertical surface wells in the Huainan coal mining area

Exploitation technology of pressure relief coalbed methane in vertical surface wells is a new method for exploration of gas and coalbed methane exploitation in mining areas with high concentrations of gas, where tectonic coal developed. Studies on vertical surface well technology in the Huainan Coal Mining area play a role in demonstration in the use of clean, new energy resources, preventing and reducing coal mine gas accidents and protecting the environment. Based on the practice of gas drainage engineering of pressure relief coalbed methane in vertical surface wells and combined with relative geological and exploration en- gineering theories, the design principles of design and structure of wells of pressure relief coalbed methane in vertical surface wells are studied. The effects of extraction and their causes are discussed and the impact of geological conditions on gas production of the vertical surface wells are analyzed. The results indicate that in mining areas with high concentrations of gas, where tectonic coal developed, a success rate of pressure relief coalbed methane in surface vertical well is high and single well production usually great. But deformation due to coal exploitation could damage boreholes and cause breaks in the connection between aquifers and bore-holes, which could induce a decrease, even a complete halt in gas production of a single well. The design of well site location and wellbore configuration are the key for technology. The development of the geological conditions for coalbed methane have a significant effect on gas production of coalbed methane wells.

Case study on the extraction of land cover information from the SAR image of a coal mining area

In this study,analyses are conducted on the information features of a construction site,a cornfield and subsidence seeper land in a coal mining area with a synthetic aperture radar (SAR) image of medium resolution. Based on features of land cover of the coal mining area,on texture feature extraction and a selection method of a gray-level co-occurrence matrix (GLCM) of the SAR image,we propose in this study that the optimum window size for computing the GLCM is an appropriate sized window that can effectively distinguish different types of land cover. Next,a band combination was carried out over the text feature images and the band-filtered SAR image to secure a new multi-band image. After the transformation of the new image with principal component analysis,a classification is conducted selectively on three principal component bands with the most information. Finally,through training and experimenting with the samples,a better three-layered BP neural network was established to classify the SAR image. The results show that,assisted by texture information,the neural network classification improved the accuracy of SAR image classification by 14.6%,compared with a classification by maximum likelihood estimation without texture information.

Failure characteristics of surface vertical wells for relieved coal gas and their influencing factors in Huainan mining area

从通过洞基于数据并且记载，我们在 Huainan 采矿区域和它的影响因素为减轻的煤气体学习了表面排水井的失败特征。结果证明排水井的损坏位置主要在西方采矿区域在基岩的上面的节在厚泥土层位于低冲积层和 lithological 接口。casing 的失败深度是 244 鈥 ? 70 m 并且在大约 270 鈥 ? 专注 60 m 深。这些损坏位置主要在划分的房顶上面在垂直的节根据岩石层的三个地区位于弯曲地区。通常， casing 以前开始使脸线变形或损坏大约 30 鈥 ? 50 m。特殊形成结构和岩石团性质是 casing 失败，高采矿高度和快进展速度的直接原因是为岩石质量的基本原因损坏。然而，到 casing 失败的地上凿穿配置和间距不是很清楚的。

Quantitative analysis of biotechnical reinforcement for a steep slope consisting of composite coal-gangue-soil medium adjacent to a mined-out area

The engineering and geological characteristics of a steep slope consisting of coal gangue, rock and soil medium in Huating coal mine have been comprehensively investigated. Owing to humid weather, heavy rainfall, vegetation and porous characteristics of the soil and rock mass, the steep slope will be destabilized and induce mud-rock flow or derive hazard easily. Firstly, based on the classical slope reinforcement theory, some regularity between the shear and displacement in the destabilized zone of the slope with or without root strength contribution is presented. Then, based on the experimental and statistical analysis of root strength, hydrological characteristics and stability status, etc., some possible biotechnical techniques for reinforcement of the steep slope have been suggested. These methods are important for quantitative analysis of destabilization of the slope and design of the biotechnical reinforcement.

Application of DEM overlaying technique in surface subsidence identification─a case study in Ruqigou coal mining area of Ningxia,China

Subsidence occurred in many parts of the world. particularly in densely populated deltaic regions, causing extremely expensive damage. It can be resulted from natural causes. man-made induced causes, or other mixed causes. For identifying surface subsidence, many techniques have been employed, for example, geodetic monitoring, airborne laser subsidence measurement system,differential S.A.R., interferometry DGPS, and satellite radar measurements. However. all these methods require large time span and a large amount of field work. With the development of GIS techniques, identification of surface subsidence is becoming a relative easy problem. Ruqigou coal mining area was selected as a case study to identify the surface subsidence with DEM (digital elevation model) overlaying techniques. The result shows that DEM overlaying technique is a very useful method on surface subsidence identification. The accuracy of the results are largely dependent on the precision of the data-input.

Simulation Test for Evolution Laws of Tensile Fractures in a Coal Mining Area

In order to study evolution laws of tensile fractures in a coal mining area, based on the classification of the fractures formed by mining, a physical simulation test was carried out to simulate the dynamic evolution process of tensile fractures in coal mining areas. The results showed that after the coal in the mining area was mined, the mining area underwent obvious movement and deformation and forms tensile fractures. As the min-ing working face was advanced, the tensile fractures underwent the dynamic process of generation, development and closure. The changing curves of density of tensile fractures with the increase of mining length of the working face liked a ladder （it increased slowly and then rapidly） and then had two peaks （the second peak was higher than the first peak）.

An Evaluation Study on Water Ecological Civilization Construction in Coal Mining Subsidence Area

By combining expert consultation and field investigation,an evaluation system,consisting of 29 indices in 5 aspects of water safety,water ecology,water management,water landscape and water culture,was established for water ecological civilization construction in coal mining subsidence areas.The weight of the indices was determined using improved group-decision fuzzy analytic hierarchy process and fuzzy mathematical method,and their score was determined according to their value before the pilot and the value at the end of the pilot.Combined with the weight,the actual score of the indices was obtained.Finally,a comprehensive index of water ecological civilization in coal mining subsidence areas was obtained.Through the weight and score of the indices,the construction status,existing problems and future tasks of coal mining subsidence areas were analyzed,in order to provide a reference for the region to further clarify the direction and key tasks of water ecological civilization construction.

Prevention and Control Mode of Desertification in China＇s State Energy Group Shendong Mining Area with Annual Coal Output of 200 Million Tons

According to the strategic goal of sustainable development,construction and management for the construction of Shendong mining area with ecological safety,the ecological restoration principle of ＂ control protects development and development promotes control＂ for desertification prevention and control was adopted,and engineering measures,plant greening measures,and enclosure management and protection measures were taken to prevent and control desertification in the mining area based on careful detailed investigation and accurate planning and design in the early period. After 32 years,the desertification ecological landscape environment of the mining area has undergone a qualitative change,and the vegetation coverage has increased from 3%-8% to above 60% after the development. The former desertification land has become a modern green energy base that has produced 200 million tons of coal every year. The construction and management mode of an ecologically safe and modernized green coal mining area built by Shendong in the desertification region of northwestern China shows that taking appropriate comprehensive ecological restoration construction technology and management measures that integrate engineering,plants and enclosure management and protection is an effective technical and management paradigm for the construction of a modernized green large-scale coal mining area in China＇s arid and semi-arid regions.

Impact of Coal Mining Subsidence on Sandy Geomorphology and Vegetation Habitat in Sandy Area

[Objectives]To explore the problem of"secondary desertification"caused by coal mining subsidence in sandy area and its control countermeasures.[Methods]The collapse fissure changes,vegetation displacement and tilt,dry sand layer and wind erosion/aeolian deposit rate of the edge,middle and basin of subsidence area were studied in detail.[Results]The width and density of fissures at the edge of subsidence area were the smallest,followed by those in the center,and the width and density of fissures in the basin of the subsidence area were the greatest,while the staggering and surface damage showed the opposite trend.The average displacement length of vegetation in the subsidence area reached 60 cm,the slope was 5.67-28.63,and the maximum wind erosion/aeolian deposit at the trunk roots was-30.52 cm/+25.41 cm,most serious at the edge of subsidence.The changes in displacement length and slope of vegetation were positively linearly correlated with the height and surface damage of collapse fissures.The thickness of dry land layer at the edge of the subsidence area reached 14 cm,4-6 cm greater than that of the control,and the thickness of dry land layer in the middle and basin of the subsidence area was both about 11 cm,1-4 cm greater than that of non-subsidence area.The wind erosion rate at the edge of the subsidence area was up to 83.34%,followed by that(52.06%)in the middle.The aeolian deposit rate in the subsidence basin was 51.84%.[Conclusions]The subsidence edge has the strongest impact on the sandy geomorphology and vegetation habitat,and is a key area for ecological restoration.It is recommended that the coal mining subsidence should be treated in a timely manner to avoid the occurrence of"secondary desertification".