Effectiveness of wetlands in retaining metals from mine water,South Africa

Wetlands are effectively used to treat mine water effluent in South Africa, where they retain toxic metals that can potentially contaminate the environment. Wetlands that are located close to the abandoned tailings dams were chosen and solidified substrate samples were collected for thin section microscopy, X‐ray fluorescence (XRF) and X‐ray diffraction (XRD) analyses. In order to determine the concentration of selected metals in the tailings dams, fine grained samples were collected and leached with a diluted nitric acid and deionised water to simulate leaching by rainwater. The results from the substrate analysis revealed an overall oxide abundance of 71.76 weight percent (%) and an elevated metal concentration, which suggest a crucial role played by pH, redox, wetland sediments and wetland plants in maintaining oxygen circulation and triggering reactions. The study confirmed the efficiency of wetlands in the attenuation of toxic metals from the mine water.     

陕西汤家沟铅锌矿地质特征及找矿潜力

陕西省白河县汤家沟地区位于旬阳地区铅锌成矿带上,该成矿带上已发现黄石板、大葫芦沟、高家沟等铅锌矿床(点)。通过对汤家沟地区区域成矿地质背景、含矿地层岩石地质特征、蚀变特征、区域地球化学特征的总结,对含矿层中典型热水沉积岩岩石学特征、含矿物质来源初步分析、热水沉积岩稀土元素地球化学对比研究等,以及将该区与邻区黄石板铅锌矿体从地层组合、蚀变种类等方面对比分析,认为该区南部和北部异常范围内,蚀变较强部位存在隐伏矿体的可能。     

贵州铜仁卜口—松桃地区铅锌矿找矿方向分析

铜仁卜口—松桃地区地处湘—黔铅锌成矿带南段铜仁境内,大地构造位于上扬子地台南部被动边缘雪峰基底逆冲过渡带。区内铅锌矿床(点)分布受区域上大断裂铜仁—保靖深大断裂带与江口—松桃—花垣(湘)断裂所夹持,矿床(点)均沿早寒武世龙王庙期碳酸盐台地边缘相藻灰岩丘体分布。根据该区内1∶20万化探Pb、Zn异常,铅矿物重砂异常,含矿地层分布及沉积相等成矿指示标志,将研究区划分为3个找矿远景区,分别为嗅脑铅锌找矿远景区、牛郎铅锌找矿远景区、卜口场铅锌找矿远景区。     

On reliability of inferring liquefied shear strengths from simple shear testing

A laboratory study was carried out to compare the behaviour of loose tailings under simple shear loading using a torsional shear hollow cylinder device (TSHC) and a direct simple shear (DSS) device, with a focus on shear strength at high strains. This work was carried out on tailings for which the critical state line (CSL) had already been defined, to enable the results to be examined in a critical state framework. The testing indicated that the shear strengths measured at high strains by the DSS apparatus were significantly higher than those measured by the TSHC under undrained simple shear loading conditions. The likely more uniform and ideal simple shear conditions developing within the TSHC, along with the better agreement of results obtained using this equipment with the expected behaviour based on the test initial states and tailings’ CSL suggest that for loose specimens the DSS may overestimate shear strength at high strains. This observation was confirmed by comparing the results of this study with other published data where both CSL and DSS test results were available. The important implications of this observation for the design and analysis of tailings storage facilities (TSFs) in the context of laboratory measurement of liquefied strengths are outlined.     

铁尾矿砂-地聚物复合材料的界面与性能

用铁尾矿砂或天然砂配制水泥/地聚物砂浆,并对不同骨料与基体间界面的化学反应、界面过渡区（ITZ）微观结构及砂浆性能进行对比研究.结果表明：掺加铁尾矿砂后,粉煤灰/矿渣地聚物溶液中的Na⁺、Si⁴⁺、Al³⁺、Ca²⁺质量浓度均有不同程度降低,其中矿渣地聚物溶液反应速率较快,对骨料表层溶解也有更强的促进作用;铁尾矿砂附近界面过渡区结构明显优于天然河砂,且铁尾矿砂-地聚物砂浆的界面纳米力学性能显著高于铁尾矿砂-水泥砂浆;用铁尾矿砂制备的砂浆强度及抗渗性也均优于天然河砂,这种差异在水泥砂浆中最小,在矿渣地聚物砂浆中最显著,而粉煤灰地聚物砂浆在后期才逐渐凸显出铁尾矿砂的优势.     

高温作用后钼尾矿混凝土单轴受压性能试验研究

为研究钼尾矿混凝土高温后的单轴受压力学性能,进行了不同目标温度（20,200,300,400,600,800 ℃）条件下钼尾矿混凝土的轴心抗压强度、峰值应变、弹性模量、泊松比、破坏形态及质量变化的试验研究。结果表明：钼尾矿混凝土试件的质量损失率随温度的升高而增加,在800 ℃时质量损失率平均为6.52%;轴心抗压强度随温度的升高而逐渐降低,800 ℃时与常温相比平均降低70.04%,且随钼尾矿掺量的增加而降低;而峰值应变随温度的升高先减后增;弹性模量和泊松比都随温度的升高而降低,在800 ℃时弹性模量和泊松比平均比常温降低88.22%和35.66%。对于弹性模量,大体上随着钼尾矿掺量的增大而减小;而对于泊松比,钼尾矿掺量100%的混凝土略大于掺量50%的混凝土。根据试验结果,建立了钼尾矿混凝土高温后的单轴受压应力-应变本构方程。     

西藏错那县西午铅锌矿床地质特征及找矿方向

西藏错那县西午铅锌矿床位于藏南地区,处于特提斯-喜马拉雅构造成矿带东缘。通过对矿床地质背景、地质特征、成矿机理和找矿方向的研究,认为成矿地质条件较好。经野外调查、钻探和样品测试分析,认为西午铅锌矿床主要受控于SN向断裂,通过构造解析认为矿区NE向断裂带及其次级裂隙既控制了中基性岩脉的侵入活动,同时又是主要的控矿、导矿和容矿构造。通过矿床成因研究,初步推断该矿床是与构造-岩浆侵入活动有关的中低温热液充填交代型矿床。加大对矿体深部的勘探力度,同时对F1、F2、F4所围限的三角形区域进行重点研究和勘查,有望扩大矿床规模。     

Time- and temperature-dependence of compressive and tensile behaviors of polypropylene fiber-reinforced cemented paste backfill

The understanding of compressive and tensile behaviors of polypropylene fiber-reinforced cemented paste backfill (FR-CPB) play crucial roles in the successful implementation of reinforcement technique in underground mine backfilling operations. However, very limited studies have been performed to gain insight into the evolution of compressive and tensile behaviors and associated mechanical properties of FR-CPB under various curing temperatures from early to advanced ages. Thus, this study aims to investigate the time (7, 28, and 90 d)- and temperature (20°C, 35°C, and 45°C)-dependence of constitutive behavior and mechanical properties of FR-CPB. The obtained results show that pre- and post-failure behaviors of FR-CPB demonstrate strongly curing temperature-dependence from early to advanced ages. Moreover, the pseudo-hardening behavior is sensitive to curing temperature, especially at early ages. Furthermore, the mechanical properties including elastic modulus, material stiffness, strengths, brittleness, cohesion, and internal friction angle of FR-CPB show increasing trends with curing temperature as curing time elapses. Additionally, a predictive model is developed to capture the strong correlation between compressive and tensile strength of FR-CPB. The findings of this study will contribute to the successful implementation of FR-CPB technology.     

利用铜陵尾矿料制备无机人造石装饰材料的研究

以铜陵尾矿料为主要填充骨料,无机胶粘剂为胶粘材料,配以无机增强剂、增韧剂及无机色粉等添加剂制备无机人造石装饰材料,研究尾矿料的合理颗粒级配及其对无机人造石产品性能的影响。结果显示,采用合理颗粒级配尾矿料成型的制品经过一定的养护制度后,抗压强度为120.6MPa,抗折强度为19.5MPa,吸水率为0.5%,光泽度为76光泽单位,性能超过JC/T 507-2012《建筑装饰用水磨石—水泥人造石》的指标,从产品性能和外观上均满足室内室外装饰使用。     

磁选含磷尾矿正浮选硅酸盐矿物抑制剂的选择

为了利用磁选含磷尾矿中的磷资源,在水玻璃和L2-Z作为硅酸盐矿物抑制剂的条件下,采用一粗一精的正浮选流程进行了浮选试验。结果表明,在磷矿浮选中添加L2-Z后,获得的磷精矿中Mg O质量分数降至1.0%以下,磷精矿的P2O5质量分数提高至36%以上。由此得出,L2-Z抑制剂对硅酸盐具有较好的抑制效果。