Spatio-temporal trends of heavy metals and source apportionment in Tolo Harbour,Hong Kong

This study provided a picture of the spatial and temporal distributions of Cr, Co, Ni Cu, Zn, As, Cd and Pb in bottom sediments of Tolo Harbour. The concentrations of the eight heavy metals differed significantly between sites due to the poor tidal flushing in Tolo Harbour. The levels of Cu, Zn, Cd and Pb were generally enriched in sediments from inner Tolo Harbour, while sediments from outer Tolo Harbour (Tolo Channel) had higher levels of Cr, Co and Ni. The redox sensitive element arsenic showed no distinct spatial pattern in Tolo Harbour. The decreasing levels of Cu, Zn, Pb and Cd in sediments with increasing distance from land demonstrated a typical diffusion pattern from land to the direction of sea. Two hot spots of Cu, Zn, Pb and Cd in sediments were located near Tai Po and Sha Tin new town, indicating that Cu, Zn, Pb and Zn were from land-derived sources. The sites with relatively high levels of Cr, Co and Ni in sediments were located in areas close to waste spoil in sea floor. The natural and anthropogenic inputs from Sha Tin and Tai Po to Tolo Harbour were mostly responsible for Cu, Zn, Cd and Pb enrichment in sediments from inner Tolo Harbour. The waste spoil in sea floor was believed to contribute to the Cr, Co and Ni in outer Tolo Harbour. The results of correlation coefficient between the eight heavy metals showed that Cu, Zn, Cd and Pb were strongly positively correlated, and Cr, Co and Ni were also significantly correlated with each other. The best explanation of strong correlation was their similar source. As, however, is not well correlated with the other seven heavy metals. The average concentrations of Cu and Zn displayed general increasing trends from 1978 to 2006 in Tolo Harbour, while the mean levels of Cr and Pb displayed a substantial decrease from 1978 to 1987, then a slight increase after 1987. No distinct temporal trends of the concentrations of Ni and As were observed from 1978 due to the inconsecutive data. On the other hand, the increasing trends of Cr, Cu, Zn, Cd and Pb were observed since 1996.     

新疆乌恰县莎里塔什组生物地层新知

对新疆乌恰县塔塔村下侏罗统莎里塔什组孢粉植物群的研究，共发现孢粉２２属２６种，植物化石１２属１５种。根据这些孢粉化石建立了一个孢粉组合，命名为Ｃｙａｔｈｉｄｉｔｅｓ－Ｃｌａｓｓｏｐｏｌｌｉｓ组合，再根据侏罗纪的标志植物锥叶蕨（Ｃｏｎｉｏｐｔｅｒｉｓ）的存在，将莎里塔什组的时代确定为早侏罗世，为乌恰地区早侏罗世生物地层提供了可靠依据     

Flow Characteristics of Cemented Paste Backfill

Cemented paste backfill (CPB) is primarily used for backfilling underground voids at George Fisher Mine (Mount Isa, Australia). The objective of this paper is to summarise the geotechnical characterisation of the tailings and the rheological properties of the CPB as determined from a laboratory testing program undertaken at James Cook University. Two binders were examined [a General Purpose cement and a slag blend cement] over a range of dosages from 0 to 6% and CPB mix solids content in the range of 72–78%. The slump tests were carried out using the standard cone (ASTM C 143) used for concrete and a cylinder with 110 mm (diameter) × 110 mm (height), whereas the yield stress was measured using a shear vane (Brookfield vane spindle V-73). The index characteristics of the tailings including the grain size distribution, liquid limit, plastic limit, specific gravity were determined as per ASTM standards. This paper will then discuss the interrelationships among the solid content, slump, saturated density and the yield stress of the CPB. It is shown that there is strong correlation between the two different slump test devices used in this study. The smaller cylindrical device appears to have good potential for slurries like mine tailings or dredged mud that have high water content for slump test. There is also strong inter-relationship among solid content, slump, yield stress, and bulk density. Increasing the solid content increases the bulk density and yield stress, but reduces the slump. While there is hardly any difference between the two binder types used in this study in terms of flow parameters, namely the yield stress and slump, the binder dosage has an effect. At any specific solid content, higher binder dosages lead to a drop in the slump and increase in the yield stress. The difference is more pronounced in dense slurries. It is also strongly believed that the trends and relationships developed in this study may be valuable for the other mining operations using CPB.     

A new locality of palygorskite-rich clay from the southeastern Yucatán: a potential material source for environmental applications

A palygorskite unit was discovered in a road cut of undifferentiated Tertiary limestone between the villages of El Pariso and San Roman (18°49.309N, 88°37.861W) in the southeastern Yucatán Peninsula, Mexico. This is the southern most locality of a clay-rich sedimentary unit reported in the literature for the Tertiary carbonates of the Yucatán Peninsula. This occurrence indicates a much wider range of palygorskite-rich clay deposition than previously recognized. The lithology is 99% clay and 1% sand to silt size diagenetic quartz grains. The clay consists of approximately 85% palygorskite, 15% montmorillonite and trace amounts of titanium oxides. EDS analyses on palygorskite are largely consistent with sedimentary palygorskites from other coastal marine settings, however palygorskite has a low total Fe content (average = 0.40 wt% expressed as Fe₂O₃) compared to many other sedimentary palygorskites. Montmorillonite chemical compositions are typical and compared to the palygorskite have substantially higher Fe₂O₃ concentrations (average = 3.90 wt%). The low percentage of coarse grains in the lithology combined with a high proportion of palygorskite and lack of detrimental trace minerals suggest the deposit is of industrial grade; however, it has limited reserves (6,000 m³). The unit could be potentially used in a wide array of environmental applications which are needed in the region including liners for landfills and constructed wetlands. The unit is in a geographic location which would serve the expanding economy of the region. This resource has the potential to have great impact on the quality of the local environment and the economy of a region under great environmental threat.     

塔里木盆地志留系沥青砂岩的特性及其成因

采用有机岩石学和有机地球化学相结合的方法,详细研究了塔里木盆地志留系沥青砂岩的特征及其成因。色质分析表明,志留系沥青砂岩含高的三环二萜烷且以Ｃ２３为主峰,与石炭系源岩不同,γ 蜡烷含量不高,代表藻类生源的β 胡萝卜烷含量较高,且具高孕甾烷、高重排甾烷的特征,反映沥青砂岩油源来自下古生界。有机岩石学研究表明,由于沥青砂岩含可溶性物质甚高,其油浸反射率（Ｒｂ为０２７％～０３６％）不能反映其真实成熟度,水浸反射率（Ｒｗ为１３５％～１５３％）与上下地层成熟度相吻合,排除了沥青砂岩“新生古储”的可能性。碳同位素分析结果进一步证实沥青砂岩源自下古生界的生油岩,是早古生代古油藏遭受后期构造破坏的结果。     

新驿煤矿下组煤矿井涌水量预测研究

在系统收集水文地质资料的基础上,运用"大井法"和水文地质比拟法对开采16煤的涌水量进行了预测,利用突水系数法,对八采区16煤底板奥灰突水危险性进行了评价,得出了突水系数分区图。经综合分析对比,采用大井法的预测结果:即开采16煤正常涌水量为482m3/h,最大涌水量为540m3/h;奥灰突水量初期为1 083～10 640m3/h,一般为660～4470m3/h;如对奥灰采取疏排降压方案,疏降排水量预计为770m3/h。此结果可作为矿井回采阶段防治水设计的参考。     

Statistical Analysis of Anisotropic Damage of the Bukit Timah Granite

Summary This paper presents a method to analyze probabilistic anisotropic initial damage of a rock mass. A three-dimensional geometric model of cracks in a rock mass is established in terms of several parameters, such as orientations, spacing and normalized sizes of cracks in the rock mass. The dip, dip direction, spacing, and normalized size of cracks of the Bukit Timah granite in Singapore were obtained from visual inspection of rock cores, color TV imaging, and impression packer tests in the boreholes at a site of geological investigation. Using the measured data, probabilistic distribution laws of geometric parameters of cracks on the surface of the boreholes are derived. Based on these statistical distributions and using Monte-Carlo simulation method, the distribution of anisotropic initial damage of the Bukit Timah granite is derived and found to have a beta distribution. This anisotropic initial damage distribution of a rock mass can be used in probabilistic analysis of rock mass responses to both static and dynamic loads.     

天然钛榴石的穆斯堡尔谱及晶体化学分析

本文收集了一组钛榴石样品,作了穆斯堡尔谱和化学分析。采用各对应双峰等值限制拟合。拟合结果,统计误差X~2均较小。文中还分析了钛榴石结构的阳离子占位情况,并对其五对双峰谱指派如下:Fe~(3+)在[Y]位和(Z)位,Fe~(2+)在{X}和[Y]位,而另一对双峰指派为Fe~(2+){X}→Fe~(3+)(Z)的电荷离域。从化学分析和穆斯堡尔谱数据求出二种方法Fe~(2+)/∑Fe的差值,说明钛榴石中有Ti~(3+)的存在,用此简便方法估算了Ti~(3+)的含量,得出了四面体中阳离子的占位择优为Fe~(3+)>(Al~(3+),Ti~(4+))的结论。     

Calcified roasting-acid leaching process of vanadium from low-grade vanadium-containing stone coal

The low-grade vanadium-containing stone coal used in this experiment was collected from Wuxi Coun- try, Chongqing City, China. The experiment focused on the vanadium recovery from roasted residue through opti- mizing the process conditions of an effective and environmentally-friendly technology, named calcified roast- ing-sulfuric acid leaching technology. By single-factor experiments and orthogonal experiments, the effects of roast- ing temperature, roasting time, sulfuric acid concentration and leaching time on the leaching ratio of vanadium were analyzed. The results showed that the leaching ratio of vanadium reached 85.5% under the proper technological con- ditions of roasting temperature=950℃, roasting time=4 h, 40% concentration of sulfuric acid and leaching time=6 h.     

Cracking mechanisms during galena mineralization in a sandstone-hosted lead–zinc ore deposit: case study of the Jinding giant sulfide deposit, Yunnan, SW China

There are two types of lead–zinc ore bodies, i.e., sandstone-hosted ores (SHO) and limestone-hosted ores (LHO), in the Jinding giant sulfide deposit, Yunnan, SW China. Structural analysis suggests that thrust faults and dome structures are the major structural elements controlling lead–zinc mineralization. The two types of ore bodies are preserved in two thrust sheets in a three-layered structural profile in the framework of the Jinding dome structure. The SHO forms the cap of the dome and LHO bodies are concentrated beneath the SHO cap in the central part of the dome. Quartz, feldspar and calcite, and sphalerite, pyrite, and galena are the dominant mineral components in the sandstone-hosted lead–zinc ores. Quartz and feldspar occur as detrital clasts and are cemented by diagenetic calcite and epigenetic sulfides. The sulfide paragenetic sequence during SHO mineralization is from early pyrite to galena and late sphalerite. Galena occurs mostly in two types of cracks, i.e., crescent-style grain boundary cracks along quartz–pyrite, or rarely along pyrite–pyrite boundaries, and intragranular radial cracks in early pyrite grains surrounding quartz clasts. The radial cracks are more or less perpendicular to the quartz–pyrite grain boundaries and do not show any overall (whole rock) orientation pattern. Their distribution, morphological characteristics, and geometrical relationships with quartz and pyrite grains suggest the predominant role of grain-scale cracking. Thermal expansion cracking is one of the most important mechanisms for the generation of open spaces during galena mineralization. Cracking due to heating or cooling by infiltrating fluids resulted from upwelling fluid phases through fluid passes connecting the SHO and LHO bodies, provided significant spaces for crystallization of galena. The differences in coefficients of thermal expansion between pyrite and quartz led to a difference in volume changes between quartz grains and pyrite grains surrounding them and contributed to cracking of the pyrite grains when temperature changed. Combined thermal expansion and elastic mismatch due to heating and subsequent cooling resulted in the radial and crescent cracking in the pyrite grains and along the quartz–pyrite grain boundaries.