The environment of coal mining areas and the economic evaluation of the land reclamation

The environment impact of the coal resources mining was analyzed. The method of economic evaluation for the coal mining was established to analyze land destruction. The opportunity cost method was used to quantitatively analyze and estimate the economic loss of the land destruction by coal mining. At the same time, the dump land reclamation of the Yuanbaoshan Open Pit was taken as an example to evaluate environmental and economical benefit with the method of economic evaluation for the coal mining areas land reclamation.

A review on investigation of water-preserved coal mining in western China

Yushenfu mining area is located in an ecological fragile area in western China, the coal seam of which is the Jurassic Ysn'an Foirnalion. The Jurassic Yan'an Formation con tains five minable coal seams, the top layer of which is thick, covered by shallow overburden and located under aquifers. Therefore, the mining induced water flowing fractured zone can easily extend to the aquifers of both the Quaternary Sarahu and Jurassic Zhiluo Formation. This would result in a series of negative hydrological and ecological effects, including groundwater leakage, groundwater lowering, furtherly causing surface vegetation withering and dying, surface water body reduction, spring drying out, and water flow of river being decreased substantially. To solve these environmental problems, several technologies have been carried out by Chinese scientists, one of which is water-preserved coal mining. This paper presents a review of the origin, definition and development of water-preserved coal mining, and its applications in Yushenfu mining area. The applicable conditions, research contents, research methodology, and technical foundation of water-preserved coal mining are addressed in this paper. The future research focuses regarding water-preserved coal mining in China are also discussed in this paper. Its results serve as a guide for selecting the methods to be preferred for mining in case the geological conditions, roof overburden structure and coal mining process are similar to Yushenfu mining area.

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.

Hydrochemical characteristics and water quality evaluation of shallow groundwater in Suxian mining area,Huaibei coalfield,China

The aim of this study is to evaluate the hydrogeochemical characteristics and water environmental quality of shallow groundwater in the Suxian mining area of Huaibei coalfield,China.The natural formation process of shallow groundwater in Suxian is explored using Piper trilinear charts and Gibbs diagrams,and by examining the ratios between the major ions.United States Salinity Laboratory(USSL)charts,Wilcox diagrams,and the water quality index(WQI)are further employed to quantify the differences in water quality.The results reveal that the main hydrochemical facies of groundwater are HC03-Ca,and that silicate dissolution is the main factor controlling the ion content in shallow groundwater.The USSL charts and Wilcox diagrams show that most of the water samples would be acceptable for use in irrigation systems.The WQI results for each water sample are compared and analyzed,and the quality of groundwater samples around collapse ponds is found to be relatively poor.

Characteristics of the main polluting trace elements in the water environment of mining subsidence pools

Mining subsidence pools are water bodies formed by soil subsidence near mines. We studied the impact the surrounding coal production activities and power plants have on these waters by measuring the concentrations of harmful trace elements in these waters. The concentration of the four elements F, Hg, Se and As increased by 0.92%, 0.78%, 0.70% and 0.81%, respectively, in the Datong mining subsidence pool from November 2004 to November 2006. The four elements increased by 1.58%, 1.23%, 1.08% and 0.92%, respectively, in the Xie’er mining subsidence pool and 1.16%, 1.06%, 1.02% and 1.01%, respectively, in the Pansan mining subsidence pool over the same time period. The absolute levels of F, Hg, Se and As in the pool are related to the background levels of the elements. A close relationship between nearby coal mines and power plants and increasing levels of the measured elements is noted.

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.

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.

Evaluation of Mine Geological Environment of Guqiao Coalmine

The geological environment is important for the development of coal enterprises. In the Guqiao coalmine, the information of coal mining subsidence, terrain landform, coal gangue utilization, mine water treatment and several on-site investigations have been analyzed. It holds that its geological environment can be evaluated from three aspects, i.e., geological disasters, terrain and landform destruction, and influence on water and soil environment. The results show that mining activities have serious impacts on geological disasters and terrain landform, while lighter impacts on the water and soil environment. According to the research results, a set of corresponding governance strategies are given. The findings can provide theoretical support for the geological environmental protection and restoration of the Guqiao coalmine.

Technology Development and Engineering Practice for Protection and Utilization of Water Resources in Coal Mining in Western China

Shanxi,Shaanxi,Inner Mongolia,Ningxia,and Gansu(hereafter generally referred as "the Western Area")are major coal-producing areas in China due to rich coal resources and good mining conditions.However,the Western Area has a serious water shortage.The surface evaporation is huge and a great amount of mine water generated in coal mining is evaporated and lost after discharging to surface.In order to protect and utilize the water resources during large-scale coal mining in the Western Area,Shenhua Group has put forward a technological idea to store mine water in underground mined areas and successfully researched and developed the coal mine underground reservoir technology by solving the technical difficulties of water source prediction,reservoir site selection,reservoir capacity design,dam construction,safety guarantee,water quality control and so on through20 years of exploration.Now Shenhua Group has successfully established a batch of reservoir in the Shendong Mining Area,obtaining great economic and social benefits.The technology is also extended to other western mining areas,providing an effective path for harmonic mining of coal and water resources in western China.

新集矿区深部1煤层底板奥灰岩溶突水危险性评价

奥灰岩溶裂隙含水层是影响华北型煤矿深部开采的重要水害,在水-岩相互作用下奥灰含水层易导致煤层底板突水。为进一步认识奥灰岩溶突水问题,文章以新集矿区深部1煤层开采为例,利用矿区近些年最新积累的奥灰钻孔资料,选取断层强度指数、断层交叉点与尖灭点、含水层水压、富水性、隔水层等效厚度、脆塑比7个因素作为奥灰岩溶突水的主控因素,并结合层次分析法(analytic hierarchy process,AHP)确定各主控因素影响权重。运用地理信息系统(geographic information system,GIS)空间分析功能建立各主控因素专题图,通过对专题栅格图归一化处理,将各主控因素按照权重进行空间复合叠加,最终获得1煤层底板奥灰岩溶突水危险性评价分区结果。将评价结果与突水系数法计算结果对比分析可知,基于GIS的煤层底板突水危险性评价方法更符合矿区实际地质情况,可以为矿区深部煤层开采与水害防治工作提供参考依据。

煤矿生产区周边水体环境重金属污染分析与治理技术

水体环境受污染会严重影响生态平衡,利用物理化学技术与生物治理技术相结合的方式,治理煤矿生产区水体环境重金属污染。在分析重金属污染情况后,考虑到重金属污染物进入水体后会出现降解、沉淀、氧化以及吸附反应,根据水体环境实时变化特征,利用物理与化学治理技术实施过滤、物理吸附、土壤淋漓以及化学固化操作。同时,利用水中微生物种群,通过生物治理的方式,消纳、转移重金属污染物。实验结果表明,该技术对水中的锰、铁以及铬等重金属元素均能高效地治理、去除。

高潜水位采煤沉陷区微塑料赋存特征及风险评估

为探明高潜水位采煤沉陷区微塑料污染赋存特征及其环境风险,选取安徽省淮南市春申湖、舜耕湿地公园两个典型采煤沉陷区为研究区域,采集了表层水体,底泥及周边农田土壤样品,采用体视显微镜、扫描电镜、红外光谱对微塑料尺寸、形状、颜色及丰度等赋存特征进行表征.结果表明:采集的样本中多为纤维微塑料和薄膜微塑料,类型主要以聚乙烯,聚丙烯为主,颜色以黄色和透明为主,粒径大多小于500μm.采煤沉陷区的地表水丰度范围为0.77~7.1pcs/L,沉积物微塑料的丰度范围为540~2800pcs/kg,周边农田土壤微塑料的丰度范围为380~2380pcs/kg.采用污染负荷指数(PLI)模型进行评估,地表水和农田土壤的风险评估都为于Ⅰ级,属于轻微污染,而沉积物中的微塑料风险评估为Ⅱ级,属于中度污染.

西部干旱半干旱煤矿区生态环境损伤特征及修复机制

我国煤炭开发重点已战略西移,实现煤炭资源绿色开采与生态协调发展,成为保障国家能源安全的重要举措之一。西部煤层大多数埋藏浅、上覆基岩薄、煤层厚,有利于一次采全高大规模井工开采或露天开采。但该地区气候干旱少雨、生态条件脆弱,大规模高强度对矿区及周边生态环境造成的损伤大。由于对开采过程中生态损伤演变机制及采后修复机理尚不清楚,没有成熟的修复理论和方法作指导,成为制约该地区煤炭高质量发展的重大难题。针对上述难题开展系统研究,认为精准勘测煤炭开采全周期工作面地质-水文地质条件和矿区生态演化特征,有助于阐明开采诱致上覆土岩破损机理、水资源散失富集与循环调运规律、生态损伤演变机理和承载力,并揭示采后矿区土岩层、水资源循环、生态自适应机理。采用植物-微生物组合修复方法,初步构建井工和露天矿山人工与自然协同的水-土-生立体耦合修复理论,提出了生态修复机制的新思考,在浅埋深矿区开采形成的裂缝发育犹如农田松土一般,成为生态修复新的契机,促进水-土-生再分配,并利用微生物修复技术,可促进矿区生态环境的正向协同发展,实现西部煤矿脆弱生态区开发“金山银山”,再造“绿水青山”的思维转变。

基于DNN的煤矿富水区探测反演方法研究

提出了一种基于DNN的煤矿富水区探测反演算法,该算法可以快速准确地实现煤矿富水区二维分布模型的重建。首先,利用时域有限差分方法(FDTD)获得不同分布模型的数值解;随后,依据数据样本搭建网络框架,网络的输入主要为电场分量,输出为相应的模型电导率参数。通过对神经网络进行训练,得到网络的最优系数,随后对富水区分布进行反演预测;结果表明:DNN算法在单个小目标异常体反演中,可以有效克服BP神经网络模型失效的问题,且对于多目标异常体的反演效果更加准确。另外,相同数据集下,DNN的训练耗时与预测耗时也少于BP神经网络。实验结果表明,该算法可以有效提高煤矿富水区探测效率。

锡林郭勒盟大型露天煤矿区地质环境时空演化评价

内蒙古锡林郭勒盟大型露天煤矿区经过20多年的开发,产生了一系列矿山地质环境问题,矿区地质环境在一定程度上遭到破坏,因此,开展大型露天煤矿区地质环境时空演化评价可为矿区生态地质环境修复提供参考。本文对锡林郭勒盟3个大型矿区进行地质环境时空演化评价。首先通过现场调查,明确了研究区主要的矿山地质环境问题,包括植被覆盖度下降、土地压占(排土场和工业场地)、地形地貌景观破坏(露天采坑)和含水层破坏等4类;其次利用遥感影像定量获取了2000—2020年之间的矿山地质环境问题信息,并建立了矿山地质环境评价指标体系;然后应用层次分析法确定了矿山地质环境评价指标的权重,并通过基于GIS的影响指数模型对矿山地质环境影响进行了评价和区划,探讨了矿山地质环境时空演化规律。研究结果表明:(1)3个大型矿区植被覆盖度下降区域的面积、排土场压占土地面积和露天采坑破坏地形地貌景观面积随时间不断增加;(2)大型矿区采矿对地质环境的影响划分为无影响区、轻微影响区、一般影响区、较强影响区和强烈影响区5个等级分区;(3)3个大型矿区地质环境时空演化规律基本相同,不同影响区的空间分布特征和面积随时间变化的规律不同。

隐伏火烧区烧变岩含水层水害治理技术研究

我国西北地区烧变岩分布范围广、孔隙裂隙发育、富水性强,是当地的主要含水层,其中的隐伏火烧区烧变岩地表遗迹不明显、发现难度大,煤矿开采一旦导通烧变岩含水层将导致水害事故,同时会破坏烧变岩含水层水资源。为治理隐伏火烧区烧变岩水害并保护烧变岩含水层水资源,分析我国烧变岩分布特征及烧变岩水对煤矿开采影响,研究隐伏火烧区烧变岩探查和治理技术,开展隐伏火烧区烧变岩含水层水害治理的示范应用,结合现场监测数据分析评价陕西柠条塔煤矿南翼隐伏火烧区含水层水害治理和水资源保护效果。结果表明:我国烧变岩主要分布于以昆仑山-秦岭-大别山为界的北方地区,隐伏烧变岩主要分布在鄂尔多斯盆地东北部、伊犁盆地南缘,被第四系松散层覆盖;隐伏火烧区烧变岩含水层与风化基岩含水层大多直接接触且连为一体,水力联系密切;烧变岩水害防治措施主要有留设烧变岩含水层防隔水煤柱、疏降烧变岩含水层积水和帷幕截流,其中截水帷幕可有效解放烧变岩含水层压覆的煤炭资源,解除烧变岩水害威胁并保护烧变岩含水层宝贵的地下水资源;通过精确探查出隐伏火烧区范围、布设注浆钻孔,将隐伏火烧区烧变岩含水层隔离为若干个含水体,断绝截水帷幕内外的水力联系,可保障工作面不受烧变岩水威胁,同时实现烧变岩水资源保护;柠条塔煤矿S1232工作面和S1233工作面隐伏火烧区烧变岩含水层治理后,其回采期间涌水量降至20m^(3)/h以内,工作面得以安全回采,截水帷幕内侧水位下降,外侧水位逐渐抬升,烧变岩水资源得到有效保护。

西部煤矿区微生物修复促进植物水分高效利用策略

西部煤矿区生态环境脆弱,叠加高强度开采致使水土流失、土壤退化、根系受损,植物水分利用效率低,生态恢复困难,提高水分利用效率成为西部矿区生态修复或重建的关键。土壤水是限制干旱半干旱煤矿区生态修复的关键因素,它连接大气水、地表水、地下水与植被生长,是水分循环与养分运输的重要载体。土壤水分的高效与合理利用关系到生态修复的成败,因此探究植物根系水分利用策略对于西部煤矿区生态修复具有重要作用。分析了国内外植物水分利用的主要研究方法,比较了不同方法之间的优缺点及相应研究进展。在干旱半干旱煤矿区受损生态环境中,采用植物-微生物联合的微生物修复技术,能提高植物水分利用效率,改善植物水分利用策略。同时,接种微生物降低了植物从浅层土壤吸收水分的比例,有效地增加植物从深层土壤中吸收和利用水分,提升了植物水分利用效率,使接菌植物在干旱半干旱煤矿区表现出更高的生态适应性。分析了目前西部煤矿区植物水分利用的研究进展和存在的问题,探讨了煤矿区微生物修复对水分利用策略的改善,提出了西部干旱煤矿区生态修复中不同植物组合对水分利用策略的影响及其研究重点,为实现矿区绿色可持续、高质量发展奠定了扎实的基础,具有重要的生态应用价值。

闭坑煤矿山酸性废水治理方法:以贵州省道真县平模山闭坑煤矿为例

以贵州省道真县平模山闭坑煤矿为例,探索适宜于岩溶山区闭坑煤矿山酸性废水(ADM)治理的实用技术,为岩溶山区开展闭坑煤矿山酸性废水治理工程提供参考。综合分析矿区地表水和地下水补、径、排关系,以及酸性废水量、水质情况,采用主动处理和被动处理相结合的方法,通过清污分流工程+酸性废水净化提升工程+人工湿地净化工程+复垦工程+附属工程进行综合治理。工程竣工后取治理区域末端水样进行检测分析,治理区域末端水质pH值为6.42,硫酸根离子(SO_(4)^(2-))浓度为248 mg/L,铁离子(Fe)浓度为5.42 mg/L,锰离子(Mn)浓度为3.28 mg/L,悬浮物浓度为46.64 mg/L,研究结果表明:5个重要监测指标pH值、硫酸根离子、铁离子、锰离子、悬浮物浓度均低于《煤炭工业污染物排放标准》(GB 20426—2006)排放标准,治理效果较为显著。在有效改善矿区生态环境的同时,新增耕地面积4800 m^(2),新增植被恢复面积918 m^(2),流域保护长度9.8 km。研究结论可为岩溶山区废弃闭坑煤矿山酸性废水治理提供技术可行、经济合理的治理模式参考。

自然和人为干扰因素对黄土高原生态环境质量变化的影响

为了识别自然和人为干扰因素对黄土高原生态环境质量变化的影响,以黄土高原为研究区,基于GEE平台和MODIS数据获取区域内2003-2022年的遥感生态指数(RSEI),利用随机森林识别自然因素和人为干扰因素对RSEI变化的驱动作用。结果表明:近20年内,(1)黄土高原的生态环境质量轻微改善,以0.002/a的速率增加,且生态环境质量空间分布总体呈由东南向西北递减的趋势,空间分布异质性较大,整体表现为良;蒙陕矿区和山西矿区大部分区域,以及黄陇矿区和宁东矿区的生态环境质量改善较为明显,占比分别为40.5%、25.7%、14.6%和19.9%,山西矿区和豫西矿区部分区域退化较为明显,占比分别为5.4%和34.3%。(2)黄土高原气温降低和升高区域分别占比46.3%和13.3%,而92.7%区域的降水不变;63.1%的土壤水、58.4%的地表径流和96.6%区域的地下水储量增加;98.5%区域的GDP增加,62.7%和20.9%区域的人口增加和降低,近70%的土地利用类型基本不变,其余区域的地物类型相互转换。(3)黄土高原RSEI改善区域主要受地表径流(占比39.8%)、地下水储量(15.7%)、GDP(13.4%)和气温(12.4%)的影响,退化区域主要受GDP(22.2%)、地表径流(21.3%)、地下水储量(16.4%)、气温(12.5%)和夜间灯光(10.5%)的影响;其次,RSEI改善的煤炭基地主要受地表径流和GDP的影响,退化的煤炭基地受GDP、夜间灯光、地下水储量和气温因素主导。综上所述,近20年内黄土高原生态环境得到改善,生态环境质量变化主要受地下水储量、地表径流、气温、夜间灯光、人口和GDP的影响。

蒙陕深埋煤层首采工作面顶板富水性和涌水量差异研究

针对蒙陕接壤区存在水文地质条件不清、水害问题多发、水资源漏失严重等问题,通过分析区内呼吉尔特矿区4个矿井首采工作面顶板地质水文地质特征、回采过程中涌水量变化及差异性,查清了矿区煤炭开采初期扰动下的水文地质条件,结果表明:四个矿井首采工作面涌水量,均随着工作面回采呈逐渐增加趋势,其中葫芦素和巴彦高勒矿井首采工作面最大涌水量分别为645.0 m^(3)/h和494.0 m^(3)/h,且七里镇砂岩含水层不同区域存在富水性差异,导致涌水量的增加呈台阶式,波动性较大,与该区域七里镇砂岩含水层厚度较薄、富水性较弱的特征一致;门克庆和母杜柴登矿井首采工作面最大涌水量分别为1372.0 m^(3)/h和938.0 m^(3)/h,且七里镇砂岩含水层整体富水性较强、富水性较均一,涌水量的增加呈平稳增加态势,波动性较小,与该区域顶板七里镇砂岩含水层厚度较大、富水性较强的特征一致。