大宝山采矿活动对环境的重金属污染调查

调查了大宝山铁铜多金属矿床固体废弃物-水相互作用对环境的重金属污染,结果表明,矿床固体废弃物导致了水、土壤的重金属污染,污染元素主要有Cd、Cu、Pb、Zn等;重金属元素的水迁移强度由大至小顺序为Cr、Cu、Zn、Ni、Cd、As、Pb、Hg;元素的生物吸收系数由大至小顺序为Cd、Zn、Hg、Ni、Cu、Cr、As、Pb,虽然水稻糙米中的重金属含量未超过国家标准,但Cd、Cr两种元素含量已远远超出了植物中毒量的下限值.     

大型铜尾矿库区节节草(Hippochaete ramosissimum)根际土壤重金属形态分布与影响因素研究

通过野外调查和实验分析,对安徽省铜陵市铜官山铜尾矿库、狮子山铜尾矿库及狮子山铜尾矿库周边农田3处生长的节节草根际与非根际土壤中重金属(Cu、Cd、Pb、Zn)的形态、含量和分布进行了研究.结果表明,节节草根际与非根际土壤重金属的主要形态分布基本一致,均表现为矿物态含量占据了重金属全量的大部分,而交换态含量偏低.与非根际土壤相比较,根际土壤中交换态、有机态重金属所占比例显著增加,其中Cu的有机结合态所占比例增加了53 25%、Cd、Pb的有机结合态所占比例增加超过17%,Zn则增加了5.67%;与此同时,碳酸盐结合态和铁锰氧化物结合态含量有所下降.统计分析表明,Cu、Cd、Pb、Zn在根际土壤中的形态分布与土壤pH值、有机质含量、植物生长等因素密切相关.     

基于时序InSAR的覆砂石尾矿坝形变演化研究

为解决目前采用在尾矿坝坝体及滩面覆盖砂石进行防尘治理与闭库,但传统监测手段难以实现坝体整体监测的问题,采用时序InSAR技术对2014年10月至2018年7月的Sentinel-1A影像进行处理,提取了对应时间段内卡房尾矿坝的形变信息,并结合实地调查及尾矿坝建设资料,研究了卡房尾矿坝的时序形变演化规律。结果表明:SBAS InSAR监测到坝体出现第1次异常形变加速运动时间与坝体开始铺设砂石工程的施工时间节点完全吻合,体现SBAS InSAR技术在受人为工程影响的坝体形变监测方面具有极高的敏感性。坝体在施工结束后,坝体形变加剧趋势并未缓解,并且出现2次加速现象,分析认为是由于在坝体铺设约2 m厚的碎砂石极大地增加了坝体荷载,打破了坝体原有的应力平衡状态,且识别出雨季对坝体形变影响显著,表明铺设砂石会使得降雨在坝体中的停滞时间加长,进一步引发非雨季期间坝体形变加剧。研究结果不仅能还原坝体出现异常形变的时间与演化过程,而且还可以对引起异常形变的内在影响因素进行分析与论证,对指导尾矿坝灾害识别、分析与治理具有重要的指导意义。     

Long-term evaluation of coal fly ash and mine tailings co-placement: A site-specific study

This study presents the results of a laboratory investigation conducted to evaluate the efficiency of coal fly ash to control the formation of acid mine drainage (AMD) from mine waste. Site-specific materials, coal fly ash from Atikokan Thermal Generating Station and mine tailings from Musselwhite mine, were mixed at different proportions for the investigation of the drainage chemistry and the optimal mix using static testing (acid–base accounting) and kinetic (column) testing. The acid–base accounting (ABA) results indicated that the fly ash possessed strong alkaline (neutralization) potential (NP) and could be used in the management of reactive mine tailings, thus ensuring prevention of AMD in the long-term. Column tests conducted in the laboratory to further investigate long-term performance of fly ash in the neutralization and prevention of acid mine drainage from tailings similarly showed that mixing fly ash with mine tailings reduces dissolution of many heavy metals from tailings by providing alkalinity to the system. It was found that a fly ash to tailings mass ratio equal to or greater than 15% can effectively prevent AMD generation from Musselwhite mine tailings in the co-placement approach.     

菱镁矿尾矿制备高活性MgO的性能表征

菱镁矿尾矿经预处理后,在一定条件下制备高活性MgO。使用热重-差热分析仪,分析菱镁矿尾矿的分解温度,应用X射线衍射、SEM分析不同煅烧温度、保温时间对MgO晶体结构的影响,并根据Scherrer公式计算MgO晶粒的尺寸。通过电导率仪测定MgO水化电导率,分析不同条件下的MgO活性,探讨煅烧温度、保温时间、颗粒细度与MgO活性之间的关系。结果发现:煅烧温度在1 050℃,保温时间60 min时,菱镁尾矿完全分解,MgO活性最佳;煅烧温度越高,保温时间越长,MgO的活性越差;MgO颗粒细度越小,活性越高。     

基于集对分析的尾矿库安全评价研究

为更好地对尾矿库的安全状况进行综合评价,针对尾矿库的特点建立了指标体系,并采用层次分析法确定各指标权重.将集对分析理论用于尾矿库的安全评价,并通过实例证明该理论适合于尾矿库的安全评价.集对分析中差异度I取1和-1.研究表明,当I=1时,指标体系中所有处于"一般安全"状态的指标项经过整改后能处于"安全"状态,此时联系度μ=0.736,尾矿库处于"安全"状态; 当I=-1时,指标体系中所有处于"一般安全"状态的指标项,在安全管理水平下降的情况下全部转为"不安全"状态,此时μ=0.114,尾矿库处于"不安全"状态.I的不同取值可反映尾矿库的具体安全状态,同时也反映尾矿库的安全管理水平,并充分体现了安全管理的重要性.研究为尾矿库的安全评价提供了一条新途径.     

Filterability of oil sands tailings

In Canadian oil sands mining operations, bitumen is extracted from oil sands using the hot water extraction process, which produces tremendous amounts of tailings. Currently, these tailings are disposed of in large ponds, in which coarse particles settle out relatively quickly and fine particles remain suspended in water and settle very slowly. After years of settling, the fine particles form a stable suspension in water known as mature fine tailings (MFTs). Long-term storage of the MFT is costly and poses a major environmental liability.Oil sands companies are now actively investigating different approaches to replace or reduce the use of oil sands tailings ponds. Filtration of the tailings to produce “dry tailings” for stacking is now being investigated as an alternative by a number of companies. Fast water drainage is a critical step for the filtration process. In this paper, we use simple laboratory-scale filtration tests to evaluate the filterability of the oil sands tailings and to generate a parameter that can be used in filtration scale-up. It was found that the filterability of the original coarse oil sands tailings was relatively low. However, after the fines are flocculated with the coarse particles to form uniform flocs the filterability was improved by several orders of magnitude. The results demonstrate that filtration of the flocculated coarse tailings to produce the “dry” stackable tailings may be viable.     

Industrial Tailings in Traunsee (Austria) Revisited: The Status of 1999

Alkaline tailings from a salt work and a soda plant have been pumped into the southernmost part of Traunsee at Ebensee for many decades. A survey in 1981 showed an accumulation of more than 3 × 10⁶ m³ alkaline mud in the Bay of Ebensee and the existence of slumping structures and turbidites in the profundal zone of the lake. A new survey of the industrial tailings has been performed in 1999. Compared to the earlier survey, the accumulation in the Bay of Ebensee has grown to >4 × 10⁶ m³, which suggests an average yearly input of 90 000 m³. Slumping structures and turbidites document the unstable situation of the tailings near the waste inlet. The lake area occasionally affected by the turbidity currents in the profundal zone has increased to 19%. Within the central profundal area these tailings reach <1 m in thickness.     

Comparison of Four <Emphasis Type="Italic">Sesbania</Emphasis> Species to Remediate Pb/Zn and Cu Mine Tailings

A 6-month greenhouse pot trial was performed, aimed at screening appropriate Sesbania species for remediation of Pb/Zn and Cu mine tailings. Performances of young seedlings of four Sesbania species (S. cannabina, S. grandiflora, S. rostrata, and S. sesban) were compared with and without inoculation of rhizobia. Seedlings were planted in two types of tailings amended with garden soil or garden soil mixed with river sediment. The results indicated that inoculated plants generally produced a higher biomass than samples without inoculation. Pb/Zn mine tailings containing rather high concentrations of total and water-soluble Cu, Pb, and Zn were toxic to plant growth compared with Cu mine tailings, according to the growth performance of the four species. Sesbania sesban and S. rostrata showed superior growth performance, compared to the other two species. Thus, they can serve as pioneer species to modify the barren environment, by providing organic matter and essential nutrients such as nitrogen, upon decomposition, in a relatively short period of time. This is especially true for S. rostrata, which is an annual plant that forms both stem and root nodules. However, a longer-term field trial should be conducted to investigate if superior species can beneficially modify the habitat for the growth of subsequent plant communities.     

WATER USE AND WATER CONSERVATION BY THE COPPER MINING INDUSTRY1

ABSTRACT: This paper examines the use of water by copper mines for treating low grade ores. The froth flotation process for treating sulphide ore and the heap leaching process for treating oxide ore are described, and ways of reducing the amount of water used in these processes are discussed. Estimates of the costs reducing water consumption are given. Finally, the circumstances in which it would be desirable for a copper mine to reduce its level of water consumption are considered.