Reductive dissolution of arsenical ferrihydrite by bacteria     

《Applied Geochemistry》2016

Mining and metallurgical processing of gold and base metal ores can lead to the release of arsenic into the aqueous environment as a result of the weathering and leaching of As-bearing minerals during processing and following disposal. Arsenic in process solutions and mine drainage can be effectively stabilized through the precipitation of ferrihydrite. However, under anaerobic conditions imposed by burial and waste cover systems, ferrihydrite is susceptible to microbial reduction. This research, stimulated by the paucity of information and limited understanding of the microbial reduction of arsenical ferrihydrite, was conducted on synthetic adsorbed and co-precipitated arsenical 6-line ferrihydrite (Fe/As molar ratio of 10/1) using Shewanella sp. ANA-3 and Shewanella putrefaciens CN32 in a chemically defined medium containing 0.045 mM phosphate concentration. Both bacteria were equally effective in their reducing abilities around pH 7, resulting in initial rates of formation of dissolved As(III) of 0.10 μM/h for the adsorbed, and 0.08 μM/h for the co-precipitated arsenical 6-line ferrihydrite samples. The solid phases in the post-reduction samples were characterized by powder X-ray diffraction (XRD), micro-XRD, scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron microprobe and X-ray absorption spectroscopy (XAS) techniques. The results indicate the formation of secondary phases such as a biogenic Fe(II)–As(III) compound, akaganeite, goethite, hematite and possibly magnetite during bacterial reduction experiments. Holes and bacterial imprints measuring about 1–2 μm were observed on the surfaces of the secondary phases formed after 1200 h of reduction. This study demonstrates the influence of Fe and As reducing bacteria on the release of significant concentrations of more mobile and toxic As(III) species from arsenical 6-line ferrihydrite, more readily from the adsorbed than from the co-precipitated ferrihydrite.  相似文献   

海州露天矿北帮边坡滑动成因机制及其稳定性分析     

周志广  王旭刚  张剑 《地质灾害与环境保护》2016,(3):20-24

以海州露天矿地质背景条件为基础,从边坡滑动形成的影响因素分析出发,研究北帮边坡滑动成因机制,确定边坡的滑动破坏模式。同时,以该边坡的典型工程地质剖面为基础,构建稳定性计算的地质模型,并采用极限平衡法——简布法、摩根斯坦-普利斯法、推力系数法等进行边坡稳定性分析,用以说明北帮边坡的整体稳定性,为滑坡治理提供科学合理的设计依据。  相似文献   

GPCAD在矿山地质环境治理工程土石方计算中的应用     

还祥生 《城市地质》2016,(2):93-97

规划总图设计软件GPCAD是基于AUTOCAD软件开发的,用于城市总体规划、控制性详细规划,主要功能有地形处理、地形分析、土石方量计算等。GPCAD软件采用方格网法进行土石方量计算,本文介绍了规划总图设计软件GPCAD计算土石方的基本原理,介绍了方格网划分、零点位置计算和工程量计算公式。矿山地质环境问题主要包括地形地貌破坏、土地资源占压和生态破坏等,矿山开采过程中形成的大量废弃土石方是造成上述问题的根源。因此,矿山地质环境治理工程项目设计、施工通常涉及到大面积的地形整治工程和大规模土石方量的计算,本文结合矿山地质环境治理工程设计实例,通过计算范围确定、方格网布设、自然标高采集、设计标高设定,介绍了各步骤的操作方法,运用GPCAD进行大规模土石方量计算,计算得出区块土石方挖、填方量和净方量。  相似文献   

The First World War from above and below. Historical aerial photographs and mine craters in the Ypres Salient     

《Applied geography (Sevenoaks, England)》2016

During the First World War, ancient siege techniques were used in an attempt to break through the stalemate in the trenches. This paper approaches the mine crater war from a completely new perspective and focuses on a landscape-scale approach rather than on fragmented individual sites. Thousands of contemporary aerial photographs have been used as a primary source of information to detect and understand the historical mine crater landscape along the former Western Front in Belgium. The paper presents a methodology for dating war features by means of a time series analysis of aerial photographs, confronting this historical landscape with a high-resolution Airborne Laser Scanning (ALS) dataset.  相似文献   

The Effects of Zn, Mn, and Co Accumulation on Growth and Chemical Composition of Fucus vesiculosus L under Different Temperature and Salinity Conditions     

IVKA M. MUNDA  V. HUDNIK 《Marine Ecology》1988,9(3):213-225

Abstract. Combined effects of temperature, salinity, and metal enrichment (Zn, Mn, Co) on the growth rate and chemical composition of Fucus vesiculosus L. were studied in culture. Factorial combinations of two temperatures and three salinities were used. The results indicated that the accumulation of Zn and Mn into algal tissue was enhanced by dilution of the media, whereas Co accumulation exhibited maxima at the medium salinity. Zn accumulation was enhanced by temperature, while the opposite was true for Mn and Co.
In the presence of metals the usual dilution-induced changes in growth activity and chemical composition of Fucus plants were altered, while responses to the temperature factor remained unchanged. In diluted media, growth activity and mannitol content decreased along with a simultaneous increase of protein content. In the presence of Zn and Mn the mannitol content exhibited peaks at the medium salinity; in the presence of Co the dilution-induced pattern remained unchanged. Salinity-induced changes in growth and protein content were altered in the presence of metals. Maxima in growth rates were found at the medium salinity. Growth was higher in extremely diluted media than in scawater, indicating an inversion of responses to the salinity factor. Both the growth rate and mannitol content were lowest under the influence of Zn.  相似文献   

Heavy metals distribution in mangrove sediments along the mobile coastline of French Guiana   总被引：1，自引：0，他引：1  

C. Marchand  E. Lallier-Vergès  F. Baltzer  P. Albéric  D. Cossa  P. Baillif 《Marine Chemistry》2006

The accumulation of nine heavy metals in fine-grained sediments from the mangrove fringed coast of French Guiana is evaluated. The dynamic features of the South American tropical coastline, from the Amazon to the Orinoco Rivers, result in mangrove sediments being alternately submitted to phases of erosion and net sedimentation a few tens of years long. This process influences the distribution of the heavy metals associated with these frequently re-mobilized deposits. Sedimentary cores and mangrove plant samples were collected, at different seasons, in various swamps characterized by different properties (content of sedimentary organic matter, distance from sea water and fresh water). The ranges of measured concentrations expressed in μmol g^− 1 were the following: Cu (0.06 to 0.61), Co (0.12 to 0.68), Pb (0.08 to 0.18), Ni (0.32 to 0.76), Cr (0.61 to 1.40), Zn (1.25 to 5.94), Mn (4.36 to 45.4) and Fe (441 to 1128). No differences were found between sediments from mangroves developing upstream and downstream of urban areas, i.e. Cayenne and Kourou. This suggests that the content of mangrove sediments in heavy metals along the coastline of French Guiana is essentially the result of the continuous alternation of accumulation and transport phases occurring upstream after departing from the Amazon watershed. The sources of this heavy metals content are thus difficult to identify. However it is well known that the alluvium produced by the natural erosion of the Amazonian soils is naturally enriched in mercury. Also, the run-off from gold mining activities is known to contribute to mercury pollution. Ranges in total Hg were between 0.15 and 2.57 nmol g^− 1, with mean values close to 0.41 nmol g^− 1, and were clearly correlated with total organic carbon except for some outstanding high values, which may be a result of rapid geochemical changes. Heavy metal concentrations showed variations with depth. The redox conditions and the decay processes affecting the organic matter control the cycling of iron and manganese, which in turn control the concentrations and associations of heavy metals. These preliminary results suggest that the variations in heavy metal content with depth or between mangrove areas result largely from diagenetic processes rather than changes in metal input resulting from local human activities.  相似文献   

甘肃省宁正矿区新庄井田煤质及工业用途评价          下载免费PDF全文

张子祥 《甘肃地质》2022,(1):36-40

甘肃省宁正矿区新庄井田位于宁县县城南约15 km处,矿区面积208 km²,属于大型井田,煤炭资源量达19. 25亿t。从煤的物理性质、煤岩性质、煤的化学性质和工艺性能等方面分析,认为矿区的煤具有中高挥发分、低灰、低硫—中硫、低磷、高发热量、弱粘结,高热稳定性、较低软化温度灰、较难磨、易选—中等可选的特点,煤类主要为不粘煤,其次为弱粘煤,少量中强粘结煤,原煤或浮选后的浮煤可作为动力用煤、气化用煤等。  相似文献   

煤矿用自动化钻机远程监测系统研制     

王天龙  马斌  董洪波 《煤田地质与勘探》2022,50(1):80-85

根据国家能源装备制造、煤矿机器人和煤矿智能化发展等政策要求,结合煤炭设备少人化、智能化发展趋势,针对现有煤矿井下钻机参数显示不全、缺乏有效监测、维修不便等问题,为实现自动化钻机地面远程监测,利用传感测量、软件开发、虚拟现实、网络通信、视频监测等技术研制了一种煤矿用自动化钻机远程监测系统。该远程监测系统包括了钻机主体、机载设备、网络通信部分和远程监测服务器。钻机主体为ZDY4500LFK型煤矿用钻机;机载设备包括了控制器和传感器组,用于实现钻机参数采集;网络通信部分包括了交换机、网关等,实现井下和地面的通信;远程监测服务器实现钻机参数和工况的监测。该系统研制后在鄂尔多斯华兴能源有限责任公司唐家会煤矿进行了现场试验,结果显示,该系统数据传输准确,可实现自动化钻机的地面监测功能,为煤矿钻机的少人化、智能化提供了保障。   相似文献   

纳米比亚湖山铀矿载铀矿物研究     

徐楷  李光来  王仁波  刘晓东  张怀峰  张雄杰  邬斌 《地质论评》2023,69(Z1):209-212

  相似文献   

笏山矿难应急救援钻孔施工技术          下载免费PDF全文

杜兵建  周兢  肖明国  孙红波  李红叶 《探矿工程》2021,48(S1):195-199

2021年笏山矿难钻孔救援是我国钻孔救援成功的典型案例。由于地层坚硬且裂隙发育,导致钻孔易偏斜且易发生卡钻事故,针对这一特殊情况采用潜孔锤空气泡沫钻进及螺杆马达纠偏等钻进工艺,成功完成了小口径生命保障孔钻探救援任务,同时本文也对生命保障孔、排水孔和大口径救生孔钻探救援技术进行了总结,对今后开展钻孔救援工作提出有待改进的问题和建议。  相似文献