石煤矿山酸性废水自净化机理及防治对策

矿山酸性废水环境问题一直是国际研究热点。该文以浙江省开化县废弃石煤矿山排放的酸性废水为调查对象,研究了其在自然环境下的自净化机理。结果表明,下游地表水水质并未因酸性废水的汇入而低于一类水质标准。通过对开化县汪川村废弃石煤矿硐酸性废水流动沟渠和下游汪川村溪流的水、底泥中铁、镉元素含量、赋存状态进行调查并辅以实验室模拟试验,得出三价铁离子在弱碱性水环境下的沉淀和对水溶态镉元素的吸附是矿山酸性废水自净化的关键。整个酸性废水自净化过程可以划分为3个阶段:地下缺氧环境下酸性废水生成-流动进入地表环境阶段,地表富氧环境下酸性废水流动阶段,地表弱碱性水环境铁元素沉淀阶段。基于矿山酸性废水的自净化原理,通过人为调节矿山酸性废水p H值和Eh值可促进AMD中铁元素氧化,并以水铁矿共沉淀和吸附作用去除水溶态镉元素。

化学淋洗法对石煤矿山放射性-重金属复合污染土壤的修复研究

石煤中含有较高含量的天然放射性核素,它的开发与利用会对环境造成放射性污染以及伴生的重金属污染等,近年来石煤的开发与利用对环境产生的放射性污染以及重金属污染等问题越发受到公众关注,江西作为全国石煤储量最为丰富的省份之一,石煤矿山大多为露天开采,废弃矿山长期受雨水淋溶、地表径流等对周边土壤环境造成了严重损害,为了对石煤矿区周边放射性及重金属复合污染土壤进行修复技术研究,采用振荡淋洗方法进行室内小试试验,根据江西省某石煤矿区现场采集的土壤检测结果显示,主要污染物指标为放射性核素铀以及重金属锌和镉;依据前人研究,针对其特有的放射性及重金属复合污染特征,选用盐酸、柠檬酸、草酸、EDTA、三氯化铁为淋洗剂,通过控制淋洗浓度、混合淋洗等因素来确定较优的淋洗条件。结果表明:各淋洗剂对复合污染土壤的去污效果综合最佳是草酸、盐酸以及三氯化铁;而不同浓度梯度下淋洗率最好的分别是1 mol/L的草酸和1 mol/L的盐酸溶液,组合淋洗剂对比单一淋洗剂的淋洗效果均有一定程度的提升,1 mol/L的草酸溶液与1 mol/L的盐酸溶液组合的淋洗剂对U、Cd、Zn的淋洗率均达到最高,分别是99.2%、97.8%和43.7%。该研究成果可用于现场淋洗修复复合污染土壤的小试,同时仍需考虑淋洗修复后土壤的潜在环境风险问题。

浙西某地石煤矿山周边耕地土壤重金属污染与生态风险评价

以浙西某石煤矿山及周边农田表层土壤为研究对象,运用潜在生态风险指数法综合评价其潜在生态危害程度。结果表明,Cd、Hg、Cu、As、Zn、Ni、Pb、Cr等8种重金属元素平均含量均高于中国土壤背景值,相关性分析表明,除Cd与Cr呈显著的正相关关系,其余元素两两呈极显著正相关关系;潜在生态风险评价表明研究区土壤环境RI平均值为250.38,属强生态危害程度,Cd元素是构成潜在生态风险的主要因素。地表水检测表明矿坑内地表水呈强酸性,Cd、Zn、Cu含量超标,以Cd超标最严重。周边农作物安全评价得出,该区农产品甘蔗Cd严重超标,农产品质量安全存在较大风险;自然修复石煤矿山地表水Cd含量超标程度高,邻近地区土壤及地表水易受影响,存在生态风险。石煤矿山周边土壤及农产品重金属含量超标严重,建议石煤矿山生态环境修复应采用自然恢复和人工修复相结合的办法,做好石煤矿山废水、废渣处理,减少因淋滤作用对地下水、土壤造成的影响。

浙江常山江源石煤矿山周边耕地土壤重金属分布特征与生态风险评价

为系统研究浙江常山何家江源石煤矿山周边耕地土壤重金属分布特征及农产品重金属健康风险,在浙江常山何家江源石煤矿山周边耕地采集了表层土壤、岩石样及水稻、甘蔗两种农产品样品,重点分析了As、Hg、Cr、Cu、Zn、Ni、Cd、Pb、Se等元素含量,采用土壤污染风险筛选值等国家标准,对该研究区土壤重金属污染进行评价,同时对农产品进行As、Hg、Cr、Cu、Zn、Ni、Cd、Pb重金属及Se等元素含量统计。结果表明,石煤矿山周边耕地除Pb含量低于全省土壤背景值外,其它元素均值都高于全省土壤背景值,土壤重金属和硒受地质背景荷塘组黑色岩系控制;除少量清洁外,轻度以上污染样品数占总样品数52%,土壤重金属污染严重。农产品重金属Cd超标严重,其中水稻全部超标、甘蔗50%超标,生态风险较大,但两种农产品富硒率都达50%以上。水稻的生物吸收系数除Hg外,As、Cr、Cu、Zn、Ni、Cd、Pb、Se等元素生物吸收系数普遍高于甘蔗。水稻根系土和稻谷Se、Cd、Ni三种元素都呈正相关,甘蔗根系土和甘蔗中Se、Cd不相关。

放射性核素及水土检测在某石煤矿山地质环境保护中的意义

随着地质调查工作重点由"资源"转为"资源与环境"并重,如何实现矿产资源合理开发和矿山地质环境有效保护也备受关注。某矿区位于安徽宁国宁墩镇,开采矿种为石煤矿,坚持"预防为主,防治结合,依靠科技进步,发展循环经济,建设绿色矿业"原则,开展石煤放射性核素检测及水土检测,经检测该矿区石煤放射性核素同时满足内照射指数(I_(Ra))<1.0和外照射指数(I_(γ))<1.0,其放射性活度符合要求;水土环境背景值中部分重金属含量超标,但并非矿山活动造成的重金属污染,在此后的矿山开采过程中仍应进行水、土样品的分析监测,为矿山地质环境保护提供技术支撑。

石煤矿山环境治理与生态修复设计探讨

生态文明建设是石煤矿山生态修复核心理念,本文对关闭后的石煤矿山的环境治理与生态修复设计工作进行了归纳总结,通过对石煤矿山遗留的酸性重金属废水,含重金属煤矸石,以及石煤自燃等污染问题分析,因地制宜采取治理措施,环境污染问题得到了有效解决。矿山生态修复后,通过种植艾草等经济作物,提升了矿山生态产品价值的转化能力。

Risk evaluation of rock burst through theory of static and dynamic stresses superposition

Rock burst is one of the most catastrophic dynamic hazards in coal mining. A static and dynamic stresses superposition-based(SDSS-based) risk evaluation method of rock burst was proposed to pre-evaluate rock burst risk. Theoretical basis of this method is the stress criterion incurring rock burst and rock burst risk is evaluated according to the closeness degree of the total stress(due to the superposition of static stress in the coal and dynamic stress induced by tremors) with the critical stress. In addition, risk evaluation criterion of rock burst was established by defining the "Satisfaction Degree" of static stress. Furthermore,the method was used to pre-evaluate rock burst risk degree and prejudge endangered area of an insular longwall face in Nanshan Coal Mine in China. Results show that rock burst risk is moderate at advance extent of 97 m, strong at advance extent of 97-131 m,and extremely strong(i.e. inevitable to occur) when advance extent exceeds 131 m(mining is prohibited in this case). The section of two gateways whose floor abuts 15-3 coal seam is a susceptible area prone to rock burst. Evaluation results were further compared with rock bursts and tremors detected by microseismic monitoring. Comparison results indicate that evaluation results are consistent with microseismic monitoring, which proves the method's feasibility.

Effect of loess for preventing contamination of acid mine drainage from coal waste

Acid mine drainage （AMD） that releases highly acidic, sulfate and metals-rich drainage is a serious environmental problem in coal mining areas in China. In order to study the effect of using loess for preventing AMD and controlling heavy metals contamination from coal waste, the column leaching tests were conducted. The results come from experiment data analyses show that the loess can effectively immobilize cadmium, copper, iron, lead and zinc in AMD from coal waste, increase pH value, and decrease Eh, EC, and 8024- concentrations of AMD from coal waste. The oxidation of sulfide in coal waste is prevented by addition of the loess, which favors the generation and adsorption of the alkalinity, the decrease of the population of Thiobacillusferrooxidans, the heavy metals immobilization by precipitation of sulfide and carbonate through biological sul- fate reduction inside the column, and the halt of the oxidation process of sulfide through iron coating on the surface of sulfide in coal waste. The loess can effectively prevent AMD and heavy metals contamination from coal waste in in-situ treatment systems.

Ecological Restoration of Abandoned Mine Land in China

Mining activities produced a lot of abandoned mine land. This paper introduced the theoretical and technical progress of ecological restoration of surface coal mines, mining subsidence land and coal waste piles in China and discussed some key problems for research in the future. Ecological restoration of abandoned mine land was related to many disciplines, and multi-disciplinary theories might make great contributes to it. Some practical techniques of ecological restoration of abandoned mine land and their demonstration bases in China were introduced. Ecosystem succession process and mechanism, structure optimization of land use and new technologies of ecological restoration of abandoned mine land should be focused on in research activities.