Development of geochemical and mineralogical methods for targeting lower environmental impact secondary copper deposits in the Troodos Massif, Cyprus

开发地球化学和矿物学方法，以寻找塞浦路斯特罗多斯地块对环境影响较小的次生铜矿床

• 批准号: NE/G012059/1
• 金额: $ 8.75万
• 依托单位: UNIVERSITY OF EXETER
• 依托单位国家: 英国
• 项目类别: Training Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FG012059%2F1
• 关键词: Development; geochemical; mineralogical; methods; targeting

The Troodos Massif, Cyprus has been mined since the Bronze age and contains around 90 copper deposits (Robb, 2005). Mining has mainly concentrated on the primary volcanogenic massif sulphide-type deposits containing pyrite and chalcopyrite, with lesser sphalerite. With the recent increase in the price of Cu, the range of exploration targets has been broadened to include lower grade secondary (supergene enrichment) deposits. These form mainly as a result of oxidation of primary pyrite by percolating meteoric fluids which causes a reduction in pH of the fluids and subsequent dissolution of chalcopyrite. Much of the Cu enters the fluid phase and is precipitated at deeper levels as either oxides, above the water table, or as sulphides below it. The mining of secondary deposits offers environmental benefits as secondary copper minerals are more amenable to acid leaching rather than the ore beneficiation and smelting necessary for sulphide ores. The exploration for European Cu also offers financial, other environmental (lower metals miles) and strategic benefits relating to security of supply. The aim of the project is to develop new exploration tools for secondary Cu deposits by testing the hypotheses that: 1) surface gossans can be classified, based on mineralogical and geochemical criteria, into those developed from high- and low-Cu sulphide protoliths; 2) gossans formed from high-Cu protoliths may indicate the existence of secondary copper deposits at depth. The student will carrying out detailed field studies in the Troodos Massif and the collection of gossan samples and ground waters, following methods in Leybourne et al. (2006). Five gossans will be studied: the Phoenix and Three Hills deposits, with known secondary Cu mineralisation; two 'barren' gossan sites, to be identified during fieldwork and from discussions with the Cyprus Geological Survey; and the West Apliki prospect, which is as yet undeveloped (Naden et al., 2006). Samples will be examined using optical and scanning electron microscopy (at the Camborne School of Mines - CSM), and then analysed using QEMSCAN automated mineralogical assessment system (at CSM) and by Position Sensitive Detector - X-ray diffraction (PSD-XRD, at the NHM). Complementary whole-sample major and trace element data will be acquired at CSM using X-ray fluorescence and at the NHM using Inductively Coupled Plasma Optical Emission (ICP-OES) and Mass Spectrometry (ICP-MS). Spatially resolved trace element data will be obtained using Laser Ablation ICP-MS at the NHM, or BGS. A classification scheme for gossans known to be formed from high- and low-Cu protoliths will be devised on the basis of the presence/absence of relict minerals and replacement textures and the mineralogy and elemental composition of weathering phases, including clays. The extent and nature of the weathering in gossans from high-Cu protoliths will be assessed by carrying out mass balance calculations using bulk and mineral geochemical data (including rare earth elements, using the method of Boyle, 2003). The student will receive instruction in field geological mapping and sampling from all three supervisors during two field seasons in Cyprus, of four weeks each, the first to undertake detailed studies at the Phoenix, Three Hills and 'barren' sites and the second to test developed models in a semi-exploration context at the West Apliki prospect. Contacts have been made with EMed (Nikos Adamides) and the Geological Survey Department of the Cyprus government (Dr Eleni Morriseau) ensuring excellent student logistical support. Full training will be given at the NHM in PSD-XRD and geochemical (ICP-OES, ICP-MS and LA-ICP-MS) analysis and at CSM in scanning electron microscopy, X-ray fluorescence and QEMSCAN. For references see Case for Support

塞浦路斯的特罗多斯地块自青铜时代就开始开采，拥有约90个铜矿（Robb，2005）。采矿主要集中在含黄铁矿和黄铜矿的原生火山成因铜硫化物型矿床，闪锌矿较少。随着最近铜价格的上涨，勘探目标的范围已扩大到包括低品位次生（表生富集）矿床。这些形成主要是由于原生黄铁矿的氧化，通过蒸发大气流体，导致流体的pH值降低和随后的黄铜矿溶解。大部分铜进入流体相，在地下水位以上的较深处沉淀为氧化物，或在地下水位以下沉淀为硫化物。开采次生矿床具有环境效益，因为次生铜矿更容易进行酸浸，而不是进行硫化矿所需的矿石提纯和冶炼。欧洲铜矿的勘探还提供了与供应安全有关的财务、其他环境（低金属里程）和战略利益。该项目的目的是通过测试以下假设开发次生铜矿的新勘探工具：1）根据矿物学和地球化学标准，表面铁帽可分为由高铜硫化物原岩和低铜硫化物原岩形成的铁帽; 2）由高铜原岩形成的铁帽可能表明深部存在次生铜矿。学生将按照Leybourne等人（2006）中的方法，在特罗多斯地块进行详细的实地研究，并收集铁帽样本和地下沃茨水。将研究五个铁帽：Phoenix和Three Hills矿床，具有已知的次生铜矿化;两个“贫瘠”铁帽地点，将在野外工作期间和与塞浦路斯地质调查局讨论后确定;以及尚未开发的West Apliki前景（Naden等人，2006年）。将使用光学和扫描电子显微镜（在Camborne矿业学院- CSM）检查样品，然后使用QEMSCAN自动矿物评估系统（在CSM）和位置敏感探测器-X射线衍射（PSD-XRD，在NHM）进行分析。将在CSM使用X射线荧光法和在NHM使用电感耦合等离子体发射光谱法（ICP-OES）和质谱法（ICP-MS）采集补充的全样本主要和微量元素数据。将在NHM或BGS使用激光烧蚀ICP-MS获得空间分辨的微量元素数据。铁帽的分类方案，已知形成的高和低铜原岩将被设计的基础上存在/不存在的残余矿物和替换纹理和风化相，包括粘土的矿物学和元素组成。高铜原岩铁帽风化的程度和性质将通过使用大量和矿物地球化学数据（包括稀土元素，使用波义耳，2003年的方法）进行质量平衡计算来评估。学生将在塞浦路斯的两个野外季节接受所有三名主管的野外地质测绘和采样指导，每个季节为期四周，第一次在凤凰城，三山和“贫瘠”地点进行详细研究，第二次在西Apliki前景的半勘探环境中测试开发的模型。与EMed（Nikos Adamides）和塞浦路斯政府地质调查部门（Eleni Morriseau博士）进行了联系，以确保出色的学生后勤支持。将在NHM提供PSD-XRD和地球化学（ICP-OES，ICP-MS和LA-ICP-MS）分析方面的全面培训，并在CSM提供扫描电子显微镜，X射线荧光和QEMSCAN方面的全面培训。有关参考，请参见支持案例