Effects of a proline solution cover on the geochemical and mineralogical characteristics of high-sulfur coal gangue

Batch experiments were conducted to comparatively evaluate the inhibition effects and mechanisms of a low-concentration (1%) proline solution cover on the release of pollutants from high-sulfur coal gangue. High-sulfur coal gangue was continuously immersed in a proline solution and in deionized water (as a control treatment) for 540 days. The results showed that the coal gangue in the control treatment was oxidized and generated leachate with poor water qualities, i.e., the leachate exhibited lower pH values, higher redox potential values, higher pollutant concentrations (SO₄^2?, Fe, Mn, Cu, and Zn), and high levels of acidophilic sulfur-oxidizing bacteria. However, compared to the control treatment, the addition of the proline solution (1%) significantly improved the water quality of the leachate by significantly reducing the Eh values, the pollutant concentrations (SO₄^2?, Fe²⁺, Fe, Mn, Cu, and Zn), and the activity of acidophilic sulfur-oxidizing bacteria and by significantly increasing the pH value to neutral. The proline treatment significantly inhibited the oxidation of coal gangue and the release of pollutants, mainly by inhibiting the activity of acidophilic sulfur-oxidizing bacteria and by altering the heavy metal fractions and the mineralogical characteristics. Therefore, in engineering practice, workers should consider using an environmental friendly aqueous proline solution cover to achieve the in-situ control of pollutant releases from coal gangue dumps.     

Geochemical and Petrological Studies on the Early Carboniferous Sidingheishan Mafic–Ultramafic Iintrusion in the Southern Margin of the Central Asian Orogenic Belt, NW China

The Sidingheishan mafic-ultramafic intrusion is located in the eastern part of the Northern Tianshan Mountain, along the southern margin of the Central Asian Orogenic Belt in northern Xinjiang autonomous region of China. The Sidingheishan intrusion is mainly composed of wehrlite, olivine websterite, olivine gabbro, gabbro and hornblende gabbro. At least two pulses of magma were involved in the formation of the intrusion. The first pulse of magma produced an olivine-free unit and the second pulse produced an olivine-bearing unit. The magmas intruded the Devonian granites and granodiorites.An age of 351.4±5.8 Ma(Early Carboniferous) for the Sidingheishan intrusion has been determined by U-Pb SHRIMP analysis of zircon grains separated from the olivine gabbro unit. A U-Pb age of 359.2±6.4 Ma from the gabbro unit has been obtained by LA-ICP-MS. Olivine of the Sidingheishan intrusion reaches 82.52 mole% Fo and 1414 ppm Ni. On the basis of olivine-liquid equilibria, it has been calculated that the MgO and FeO included in the parental magma of a wehrlite sample were approximately10.43 wt% and 13.14 wt%, respectively. The Sidingheishan intrusive rocks are characterized by moderate enrichments in Th and Sm, slight enrichments in light REE, and depletions in Nb, Ta, Zr and Hf. The ε_(Nd)(t) values in the rock units vary from +6.70 to +9.64, and initial ~(87)Sr/~(86)Sr ratios range between 0.7035 and0.7042. Initial ~(206)Pb/~(204)Pb, ~(207)Pb/~(204)Pb and ~(208)Pb/~(204)Pb values fall in the ranges of 17.23-17.91,15.45-15.54 and 37.54-38.09 respectively. These characteristics are collectively similar to the Heishan intrusion and the Early Carboniferous subduction related volcanic rocks in the Santanghu Basin, North Tianshan and Beishan area. The low(La/Gd)_(PM) values between 0.26 and 1.77 indicate that the magma of the Sidingheishan intrusion was most likely derived from a depleted spinel-peridotite mantle.(Th/Nb)_(PM)ratios from 0.59 to 20.25 indicate contamination of the parental magma in the upper crust.Crystallization modeling methods suggest that the parental magma of the Sidingheishan intrusion was generated by flush melting of the asthenosphere and subsequently there was about 10 vol%contamination from a granitic melt. This was followed by about 5 vol% assimilation of upper crustal rocks. Thus, the high-Mg basaltic parental magma of Sidingheishan intrusion is interpreted to have formed from partial melting of the asthenosphere during the break-off of a subducted slab.     

“老脚印”对自升式钻井平台插桩滑移的影响研究

渤海海域自升式钻井平台作业频率高,在同一区块多次插桩作业情况多,为自升式平台插桩作业带来严重的滑移风险。通过建立常用的两种类型桩靴的有限元分析模型,采用模拟计算和对比分析的研究方法,对在“老脚印”不同距离位置插桩时,桩基土体的塑性破坏特性、运移规律及桩靴所受侧向滑移力进行了模拟研究,得出了在不同土质条件下,桩基土和桩靴的受力特性及规律,分析了不同位置的“老脚印“对自升式平台插桩滑移风险的影响。     

微波消解―ICP―MS法测土壤和水系沉积物样品中的碘

介绍了用微波消解处理土壤和水系沉积物样品,用电感耦合等离子质谱仪(ICP-MS)快速高效测试碘的方法。方法的检出限为0. 012μg/g。所选的12个土壤和水系沉积物国家一级标准物质12次测定,除GBW07307a的RSD小于10%外,其余RSD值均小于5%,12次测试的平均值和标准值对数差绝对值均小于0. 05。方法加标回收率在98. 6%104. 6%之间。     

PNN在煤田随钻测井岩性判识应用研究

介绍了PNN方法原理及其算法训练学习过程,详细阐述了网络识别岩性参数的选取、岩性识别模型的建立过程.通过对比研究PNN与其他6种岩性识别方法,分析相同条件下预测结果,得到不同识别方法的优劣性.经研究发现,PNN概率神经网络方法在生产应用中效果更佳、训练识别用时最短.利用人工智能神经网络对测井数据进行自动解释分析,可满足随钻测井时效性及快速解释处理的地质导向需求.     

Occurrence and conceptual sedimentary model of Cambrian gypsum-bearing evaporites in the Sichuan Basin,SW China

During the Cambrian, gypsum-bearing evaporites formed in the Sichuan Basin, SW China. These rocks are important for oil and gas sealing, but details of their distribution and origin are not well established. This study examines the regional distribution and origin of the gypsum-bearing evaporites using a comprehensive analysis of drilling data from 34 wells, 5 measured cross-sections in the basin and surrounding area, and 96 maps of area-survey data. Results show that in the stratigraphic succession, the gypsum-bearing evaporites occur mainly in the Lower Cambrian Longwangmiao Formation, the Middle Cambrian Douposi Formation, and the Middle-Upper Cambrian Xixiangchi Group. Geographically, the rocks are found mainly in the southeastern part of the basin, and the distribution of deposits shows an overall SW-NE trend. The sedimentary environments for evaporite formation were evaporative lagoon and inter-platform basin in a platform setting. Gypsum was generated by the underwater concentration of sea water in a strongly evaporative environment. Both an evaporative restricted platform and a mixeddeposition restricted platform model appear to be applicable to the development of gypsum in the Sichuan Basin. The gypsum-bearing evaporites with the best sealing capacity are located mostly in the southeastern part of the basin. These constraints can be applied directly to regional exploration, and have implications for the regional paleogeography and paleoclimate.     

Evaluating igneous sources of the Taveyannaz formation in the Central Alps by detrital zircon U–Pb age dating and geochemistry

Late Palaeogene syn-tectonic volcanic products have been found in the Northern Alpine foreland basin and in the South Alpine hemipelagic basin. The source of abundant volcanic fragments is still in debate. We analyzed the geochronology and geochemistry of detrital zircons, and evaluated their temporal and genetic relationships with potential volcanic sources. The study shows that the detrital zircon U–Pb age patterns have two major age groups: a dominance (ca. 90%) of pre-Alpine zircons was found, as commonly observed in other Alpine flysch formations. These zircons apparently derived from erosion of the early Alpine nappe stack in South Alpine and Austroalpine units. Furthermore, a few Neo-Alpine zircons (ca. 10%) have ages ranging from Late Eocene to Early Oligocene (~ 41–29 Ma). Both source materials were mixed during long riverine transport to the basin margins before being re-deposited by gravity flows. These Palaeogene ages match with the activity of Peri-Adriatic magmatism, including the Biella volcanic suite as well as the Northern Adamello and Bergell intrusions. The values of REE and ¹⁷⁶Hf/¹⁷⁷Hf_(t) ratios of the Alpine detrital zircons are in line with the magmatic signatures. We observe an in time and space variable supply of syn-sedimentary zircons. From late Middle Eocene to Late Eocene, basin influx into the South Alpine and Glarus (A) basins from the Northern Adamello source is documented. At about 34 Ma, a complete reorganisation is recorded by (1) input of Bergell sources into the later Glarus (B) basin, and (2) the coeval volcaniclastic supply of the Haute-Savoie basin from the Biella magmatic system. The Adamello source vanished in the foreland basin. The marked modification of the basin sources at ~ 34 Ma is interpreted to be initiated by a northwestern shift of the early Alpine drainage divide into the position of the modern Insubric Line.     

A simple approach to evaluating leakage through thin impervious element of high embankment dams

Internal erosion is the most common reason which induces failure of embankment dams besides overtopping. Relatively large leakage is frequently concentrated at defects of impervious element, and this will lead to eventual failure. The amount of leakage depends not only on integrity of impervious element, but also on dam height, shape of valley, shape of impervious element and water level in reservoir. The integrity of impervious element, which represents the relative level of seepage safety, is not easy to be determined quantitatively. A simple method for generalization of steady seepage state of embankment dams with thin impervious element is proposed in this paper. The apparent overall value of permeability coefficient for impervious element can be obtained by this method with reasonable accuracy and efficiency. A defect parameter of impervious element is defined as an index to characterize seepage safety of embankment dams. It equals the ratio of the apparent overall value of permeability coefficient to the measured value in laboratory for intact materials. Subsequently, seepage safety of three dams is evaluated and the evolution of defect level of impervious element of dams is investigated. It is proved that the newly proposed method in this paper is feasible in the evaluation of relative seepage safety level of embankment dams with thin impervious element.     

In situ investigation into fracture and subsidence of overburden strata for solid backfill mining

Controlling the subsidence of overburden strata is the main objective for backfill mining technology. In order to understand the controlling effect of filling body, a detection scheme with three direction boreholes was designed in the tailgate of T₃290 mining face in Tangshan Coal Mine to monitor the fracture developing process of overburden strata. In addition, a few displacement and stress sensors used for monitoring the roof subsidence and filling body stress were arranged behind the longwall face to monitor and record the force and deformation of gangue. The field investigation shows that the solid backfill mining technology can effectively reduce the fracture of overburden strata, i.e., the fracture height and the damage degree. The subsidence of overburden strata is mainly caused by the subsidence of roof which is divided into four stages: roof subsidence stage of mining face, rapid subsidence stage of gob roof, relatively stable stage, and long-term rheological stage. The gauge plays an essential role in slowing down the subsidence in each stage of the overburden subsidence, especially the relatively stable stage.