Investigation of the potential for mineral carbonation of PGM tailings in South Africa

Increasing atmospheric CO₂ concentration is currently of considerable concern in terms of global warming. A possible technology that can contribute to the reduction of CO₂ emissions is its sequestration by mineral carbonation. In this study, tailings from several different platinum mines in South Africa will be mineralogically characterised and their potential for mineral carbonation reviewed. Mg and Ca-rich minerals (plagioclase, olivine, orthopyroxene, clinopyroxene) present in the tailings are good candidates for mineral carbonation, which mimics natural weathering processes in which these minerals react with gaseous CO₂ to form Ca or Mg carbonates. Since the reaction is influenced by particle surface area, the ultra fine grained nature of the PGM tailings provides another reason for the promise of PGM tailings for mineral carbonation. A preliminary ranking of the tailings samples and their efficacy for mineral carbonation has been developed according to whether the samples showed harzburgtic (e.g. Northam Platinum mine), pyroxenetic (e.g. BRPM) or noritic mineral assemblages. This information and understanding will assist in identifying opportunities and guiding the development of engineered facilities for the sequestration of CO₂ by means of mineral carbonation.     

尾砂库地震砂土液化判别与分析——以铜陵市水木冲尾砂库为例

尾砂是选矿分选作业的产物之一,通过堆积处理形成的尾砂库是重大危险源。尾砂库在地震作用下极易出现液化现象,导致库体失稳,出现溃库风险。以铜陵市水木冲尾砂库为例,采用标准贯入法、静力触探法和剪切波速判断法分析尾砂库地震砂土液化,结果表明饱和尾粉砂和尾细砂易在地震作用下产生液化。提出有关建议对策,对提高城市抗震设防工作有实际意义。     

Stability analysis of a copper tailings dam via laboratory model tests: A Chinese case study

The upstream method is a popular method for raising tailings dams. Currently in China there are more than 12,000 tailings impoundments and almost 95% of them use the upstream method for the construction of the dam. Statistical data has shown that the tailings impoundment is one of the main sources of risk in the mining industry. Failures of tailings impoundments have resulted in the loss of many lives, considerable property damage, and irreversible pollution in downstream areas. Therefore, the safety of tailings management facilities has been of increasing concern to governments and local communities. The management of a conventional tailings storage facility requires the maintenance of a high level of structural stability. Therefore, according to the relevant mine Acts, the mine operators are required to conduct stability analyses for all types of tailings facilities, whether they are new, active, or decommissioned. For the stability analysis of tailings dams, the accurate profile of the tailings dam is very important. The profiles are easily obtained for both active and decommissioned tailings facilities because their data can be collected through field investigations. However, collecting basic data from newly constructed tailings facilities is difficult. In this paper, a laboratory physical model test has been performed. The construction process for new tailings impoundment has been physically simulated in the laboratory, where the tailings particle composition and distribution below a beach, the change of phreatic surface of the dam, and the engineering properties of the tailings of the dam profiles have been measured. A new tailings facility, Yangtianqin tailings impoundment, owned by Tongchang copper mine of Yuxi Mine Co., was used as a case study to illustrate the physical modeling of the tailings dam. In the model test, the geometrical model of pond area was constructed according to the scale factor, λ_L, of 1:200 (model:prototype), and the tailings discharge system was also established, the tailings slurry then being discharged based on the design data. Finally, on the basis of the model test results on profiles, the stability analysis of the tailings dam at different heights was conducted under different conditions. The model test results and stability analysis show that the height of the tailings dam should be less than that originally planned. The original design of Yangtianqing tailings impoundment should therefore be revised for the safety of the tailings impoundment.     

Ecology of a hypersaline gold mining tailings facility in the Eastern Goldfields of Western Australia: a case study

Vertebrate wildlife use of a peripheral discharge hypersaline tailings system in the Eastern Goldfields of Western Australia was documented between 26 October 2005 and 17 November 2006. Wildlife species ecology, visitation patterns and drinking and foraging behaviour are described. A range of birds (waterbirds, waders and passerines) inhabit, and to varying degrees interact with, mine waste solids and solutions. Insectivorous bat abundance and composition is significantly lower over this tailings storage facility (TSF) compared with the Kalgoorlie – Boulder sewerage works. Macro-invertebrate sampling has found that the solutions and slurry are essentially abiotic, containing no in-situ aquatic macro-invertebrates. Airborne macro-invertebrates are trapped in solutions and wet tailings and are measured. Macro-invertebrates strongly influence vertebrate wildlife presence, behaviour and consequent exposure to mine waste solutions. Wildlife inadvertently ingest solution and slurries on insects picked from the surface of solutions and wet tails and this is the primary ingestion pathway of contaminants in solution. This behaviour was exhibited primarily amongst waders of the family Charadriidae, Scolopacidae and opportunistically by Hirundinidae and Corvidae. No wildlife was observed to drink hypersaline mine waste solutions. Wildlife can differentiate between the tailings system in question and other water bodies and this is reflected in visitation rates, abundance and species composition. This study provides a detailed ecological study of wildlife interaction with this hypersaline TSF. Additional material will be published subsequently to further examine the mechanisms by which mine waste solutions in this tailings system pose a risk to wildlife. Limited literature exists on protocols for monitoring wildlife that interact with mine waste solutions within tailings systems. Knowledge of tailings dam ecology is required to develop site-specific monitoring protocols that adequately document the risks these facilities pose to wildlife.     

Mitigating the generation of acid mine drainage from copper sulfide tailings impoundments in perpetuity: A case study for an integrated management strategy

Acid mine drainage (AMD) is one of the most serious and pervasive challenges facing the minerals industry. Current philosophy in sulfide tailings management takes an end-of-pipe approach which is yet to be shown to be sufficient to prevent post-closure impacts from AMD and guarantee “walk-away” status. An improved, integrated approach to tailings management and AMD mitigation is proposed, whereby conventional tailings are separated with the use of flotation into a largely benign tailings stream and a sulfide-rich product. The key features of this conceptual approach are outlined and partly demonstrated for the case of porphyry-type copper sulfide tailings. The significance of this approach is that it provides a basis for the identification of opportunities for the development of new process designs incorporating waste management systems for mitigating AMD in a manner consistent with the principles of cleaner production and sustainable development.     

深凹露天矿采场内流场分布规律的试验与数值模拟

为探究大气风速对深凹露天矿山爆破排烟时间的影响,采用CFD数值模拟方法构建了深凹露天矿山爆破非稳态数值模型,模拟大气风速为3、6、9、15 m/s和不同爆破位置条件下炮烟扩散场景,研究了不同大气风速对深凹露天采坑内风流场特征和爆破排烟时间的影响。研究结果表明：不同爆破位置下,随着大气风速的增大,露天采坑内的风流分布呈现出单复环流向双复环流结构的转变;当大气风速大于6 m/s后,随着大气风速的增大,爆破炮烟排烟时间下降的幅度逐渐减小,大气风速对排烟时间的影响逐渐降低;不同爆破位置下,随着大气风速的增大,露天采坑爆破炮烟排烟时间均呈现下降趋势,且与大气风速呈现良好的指数函数关系。

     

基于特征光谱的矿物组分提取：以新疆包古图斑岩铜矿钻孔岩芯样品分析为例

为研究包古图斑岩铜矿的矿床模型,文章引入基于特征光谱的矿物组分快速提取方法对岩芯样品的光谱进行蚀变矿物含量提取。该方法是将光谱曲线每个吸收峰近似为三角形,提取三顶点数值(波长与反射率)。假设每个顶点反射率为纯矿物光谱的线性叠加,结合含量来建立等式。以美国地质调查局矿物光谱库光谱为端元光谱。通过解方程组获取矿物组分。将提取出的钾化、石英—绢云母化和青磐岩化三种蚀变生成柱状图,结合实地测量的铜元素含量柱状图进行对比分析,总结出包古图斑岩铜矿垂向上的蚀变分带规律和铜矿化的分布规律。基于特征光谱的矿物组分快速提取方法可有效提取感兴趣的蚀变矿物,在矿床研究中具广泛应用前景。     

Cement hydration and durability of low sulfide tailings-based renders: A case study in Moroccan constructions

Appropriate tailings management is one of the main requisites for sustainable development in the mining industry. This research study aims to assess the use of low sulfide or sulfide free tailings (LST) as aggregates for rendering mortars, focusing on their cement hydration and durability. An authentic case study in Moroccan constructions is additionally used to assess long term behavior of LST-based renders in actual field conditions. To address such needs, renders sampled from wall constructions and laboratory-made specimens were firstly characterized by means of thermo gravimetric analysis (TGA), X-ray diffraction analysis (XRD), scanning electron microscopy investigation (SEM) and mercury intrusion porosimetry (MIP). Renders were then exposed to standard detrimental agents (moisture, sulfate water and acid rain) to assess their long term behavior. Experimental results confirmed that LST-based renders seem to involve different cement hydration processes, which lead to larger pore size distribution and lower CSH and portlandite content. These observations significantly influence their susceptibility to cracking and sulfate attack resistance.     

煤矿井下CO来源辨识与浓度超限原因研究——以内蒙古串草圪旦煤矿为例

为准确辨识井下CO来源,查明CO异常涌出与浓度超限原因,更好指导煤矿安全生产工作。以内蒙古串草圪旦煤矿为研究实例,统计了该矿井下6103、6104和6106工作面1059个气样组分测试数据,分析了采煤工作面、密闭采空区CO浓度变化特征,确定了井下CO主、次要来源,探讨了地质因素、工程因素对CO浓度超限的影响。研究结果表明:所有统计气样中,CO与O₂浓度具有较好的负相关性,CO浓度超限主要在工作面上隅角、支架、密闭采空区等通风条件较差的位置;CO主要来源于煤炭开采氧化自燃,局部存在煤天然氧化次生CO;开采煤层埋藏浅、小型逆断层发育及煤变质程度低是CO浓度超限的地质原因;工作面长度过大,通风方式不合理是CO浓度超限的工程原因;地质与工程因素共同作用下,煤炭开采氧化自燃CO与天然次生CO叠加涌出,导致在风流速度低的位置CO积聚而引起井下CO浓度超限。     

煤矿特殊工种员工安全心理参数的研究:以矿井主提升司机为例

随着矿产安全资源不断向地层深部开采,矿井亦不断延伸,尤其是千米深井日渐增多,矿井动力提升速度和提升功能不断加快、增强,矿井数字化水平提高,对矿井动力操控员工主提升司机的心理反应能力、注意能力、时空判断能力等一系列心理素质水平的要求不断增强.员工的反应准确性、注意集中和分配能力,以及情绪稳定性和人格状况是共同构成影响员工操控行为安全稳定的核心心理品质.探究矿井动力提升系统操控员工主提升司机的各项安全心理阈限值及其安全心理参数标准,建立员工安全心理选拔准入制,是保障矿井人-机和谐安全运行的重要措施.     

AMICS测试技术在铌矿中的应用—以竹溪铌矿为例

铌的用途广泛,现代工业生产对铌的需求量巨大.我国铌矿资源储量虽较高,但一般品位低,开发难度大,因此利用率较低.利用国际先进的岩石、岩屑矿物参数自动定量分析系统(AMICS)对湖北竹溪县铌矿进行研究,查明了该区富Nb岩体为粗面质火山角砾岩,而Nb元素赋存在易解石、铌铁矿及钛铁锰矿内.使用此方法弥补了常规技术手段难以完成的...     

传统资源量估算方法在第三类矿产中的应用与对比研究——以宁夏某建筑用石灰岩矿山为例

第三类矿产资源量估算一般采用传统资源量估算方法,但是不同方法估算的结果相差较大。本文以宁夏某建筑用石灰岩矿山为例,利用AutoCAD软件建立了矿山可采范围模型并测量了资源量,通过与利用平行断面法、水平断面法和水平投影地质块段法估算的资源量结果进行对比,发现平行断面法误差最大,水平投影地质块段法次之,水平断面法最小。研究结果表明:对于矿体形态简单矿山,上述三种方法均可采用,一般宜采用平行断面法或水平投影地质块段法;对于矿体形态复杂矿山,应该优先采用水平断面法,并根据矿体形态变化,选择合适的水平断面。     

井中三分量磁法测量在深部找矿中的应用——以金岭铁矿区磁异常解析为例

基于地面高精度磁法测量难以解决危机矿山深部找矿突破的问题,以井中三分量磁法测量为研究对象,结合王旺庄、侯家庄和南龙磁异常,分析了井中三分量磁法测量在深部找矿中的应用效果.研究结果表明,根据井中三分量磁法测量结果,当矿体在观测孔以北时,ΔZ曲线呈反"S"型,当D大时,正值小于负值;若D很大时则呈似"C"型曲线;当D减小,...     

鄂西地区五峰组—龙马溪组岩石相与页岩气富集关系分析——以鄂红地1井为例

鄂西地区页岩气勘探起步较晚,现阶段成果显示该区具有较好的页岩气勘探开发前景,尤其是五峰组—龙马溪组页岩受到诸多关注,但关于该区的岩石相划分和岩石相与页岩气富集关系的研究还未系统开展。目前,涪陵气田和威远—长宁国家示范区的成功商业化显示龙一段为勘探开发潜力最大的层段,通过对鄂西地区地质调查井(鄂红地1井)龙一段岩石相开展定量划分,旨在揭示该区不同时期五峰组—龙马溪组岩石相特征,从而为优质页岩分布预测提供科学依据。采用系统取芯、岩芯观察、笔石生物地层划分、相划分等方法,结合TOC含量、主微量元素、矿物成分、氩离子抛光、含气性测试等系统测试和分析,主要进行了2个方面的研究:(1)从岩性、岩矿、地化、古生物、电性等方面入手,将龙一段划分为浅水陆棚和深水陆棚相,然后利用TOC含量、石英、黏土矿物和笔石4个参数对鄂红地1井龙一段的岩性进行定量分级,将龙一段页岩进一步划分为8类岩石相。其中,富碳富硅富笔石硅质页岩、富碳富硅富笔石放射虫硅质页岩相为最有利岩石相,为页岩气勘探开发的最有利层段。(2)探讨了不同岩石相与微量元素、储集空间和含气量之间的关系。岩石相通过有机质丰度和矿物组分控制了页岩气富集,其...