The use of helium in mineral exploration

A literature review of the source and occurrence of helium shows that it can, under favorable conditions, lead to the discovery of radioactive ore deposits, oil and gas pools, and fracture zones associated with mineral occurrences. Analytical results show that anomalous helium is present in groundwaters and near uranium occurrences and thus can aid in the identification of uranium occurrences or prospective target areas for uranium exploration.     

Sustainable mineral resources management: from regional mineral resources exploration to spatial contamination risk assessment of mining

Wide-spread environmental contamination associated with historic mining in Europe has triggered social responses to improve related environmental legislation, the environmental assessment and management methods for the mining industry. Mining has some unique features such as natural background contamination associated with mineral deposits, industrial activities and contamination in the three-dimensional subsurface space, problem of long-term remediation after mine closure, problem of secondary contaminated areas around mine sites, land use conflicts and abandoned mines. These problems require special tools to address the complexity of the environmental problems of mining-related contamination. The objective of this paper is to show how regional mineral resources mapping has developed into the spatial contamination risk assessment of mining and how geological knowledge can be transferred to environmental assessment of mines. The paper provides a state-of-the-art review of the spatial mine inventory, hazard, impact and risk assessment and ranking methods developed by national and international efforts in Europe. It is concluded that geological knowledge on mineral resources exploration is essential and should be used for the environmental contamination assessment of mines. Also, sufficient methodological experience, knowledge and documented results are available, but harmonisation of these methods is still required for the efficient spatial environmental assessment of mine contamination.     

区域化探异常元素分带与找矿远景分析

延吉石人金异常位于五凤—汪清—六道崴子金、铜成矿带西段,成矿地质条件十分有利。本文根据对大黑山条垒和吉林槽区中低温岩浆—热液型金银矿区域异常元素水平分带序列特征的研究,详细说明了矿上部位、矿体部位、矿下部位异常元素水平分带序列及其模式。据此研究成果,对石人金异常的剥蚀程度进行了预测,认为石人金异常属典型的隐伏矿矿致异常,显示了良好的找矿前景。     

Host-rock lithogeochemistry applicable to exploration in the Hambaeg syncline (Hambaeg Basin), Korea

Cambro-Ordovician sedimentary rocks of the Hambaeg syncline include the Jangsan Quartzite, the Myobong Slate and the Great Limestone Group. Most of the important ore deposits, such as the Sangdong (W), Geodo (Fe-Cu) and Yeonhwa (Pb-Zn) mines are localized at the base of the Great Limestone Group as well as in the interbedded limestones of the Myobong Slate, located on the southern limb of the synclinorium. The northern limb has a high exploration potential for deposits of the same types. Sedimentary rocks around the Sangdong deposit have been analyzed to test the potential of lithogeochemistry in exploring for W in the northern limb.The uppermost interbedded limestone in the Myobong Slate was sampled at intervals of 500 m along a strike length of 16 km, SiO₂, CaO, Fe₂O₃, Zn and Cu are anomalous in areas where exploration drilling has located tungsten bearing skarn at a depth of 400 m. In the Myobong Slate, Fe₂O₃/FeO ratio is lower (about 0.2) near mineralized zones than near barren zones (about 0.6). This is consistent with the formation of the W skarns by relatively reduced fluids. The Sn content of rocks and ores suggests that the alteration is of hydrothermal metasomatic origin, since most of rocks in the mineralized zone show distinctively higher contents of Sn than in unmineralized zones.Geochemical haloes such as those described may prove applicable in exploration for blind ore bodies.     

新疆哈拉奇区域地质矿产调查新成果和主要进展

简要概述了新疆哈拉奇地区区域地质矿产调查过程中取得的新成果和主要进展。新建晚石炭世—早二叠世碳酸盐台地深水斜坡相的哈拉奇组;在石炭系—二叠系中共识别出4个带和1个珊瑚组合;在志留系中识别出笔石组合带;在石炭纪别根他乌组中发现多套古岩溶角砾岩层,在哈拉奇组中发现深水重力流沉积;识别厘定出石炭系/泥盆系和志留系/奥陶系2个平行不整合;依据不整合面划分2个构造层,并识别出3期区域性褶皱构造;划分出6个区域磁异常,4个高磁异常,并进行了查证和解译;圈定水系沉积物综合异常14处;探索性地开发针对数字化填图系统的Dliner数字化整饰平台。     

新疆哈拉奇区域地质矿产调查新成果和主要进展简

简要概述了新疆哈拉奇地区区域地质矿产调查过程中取得的新成果和主要进展。新建晚石炭世—早二叠世碳酸盐台地深水斜坡相的哈拉奇组;在石炭系—二叠系中共识别出4个带和1个珊瑚组合;在志留系中识别出笔石组合带;在石炭纪别根他乌组中发现多套古岩溶角砾岩层,在哈拉奇组中发现深水重力流沉积;识别厘定出石炭系/泥盆系和志留系/奥陶系2个平行不整合;依据不整合面划分2个构造层,并识别出3期区域性褶皱构造;划分出6个区域磁异常,4个高磁异常,并进行了查证和解译;圈定水系沉积物综合异常14处;探索性地开发针对数字化填图系统的Dliner数字化整饰平台。     

Till geochemical and indicator mineral methods in mineral exploration

This paper summarizes advances since 1987 in the application of glacial sediment sampling to mineral exploration (drift prospecting) in areas affected by continental or alpine glaciation. In these exploration programs, clastic glacial sediments are tested by geochemical or mineralogical methods to detect dispersal trains of mineral deposit indicators that have been glacially transported from source by mechanical processes. In glaciated terrain the key sampling medium, till, is produced by abrasion, crushing and blending of rock debris and recycled sediment followed by down-ice dispersal ranging from a few metres to many kilometres. As a consequence of the mid-1980s boom in gold exploration, the majority of case studies and regional till geochemical surveys published in the past decade deal with this commodity. Approximately 30% of Canada and virtually all of Fennoscandia have been covered by regional till geochemical surveys that aid mineral exploration and provide baseline data for environmental, agricultural, and landuse planning. The most profound event in drift prospecting in the last decade, however, has been the early-1990s explosion in diamond exploration which has dramatically increased the profile of glacial geology and glacial sediment sampling and stimulated changes in sampling and analytical methods.     

成矿定量预测与深部找矿

成矿预测是在不确定条件下制定最优决策的工作。成矿预测作为一种地质系统,与其他技术、经济系统存在重要区别。由于矿床类型的多样性,矿床成因的复杂性,控矿因素的隐蔽性和找矿信息的多解性,成矿预测结果具有不确定性并常常因人而异。探索成矿预测过程客观化、定量化和精确化一直是成矿预测学的前沿课题。文中以个旧锡矿为例展示致矿地质异常与矿体空间产出及分布的密切关系,强调以"求异"准则为指导的成矿定量预测的重要性。当今地质勘查工作面临深部找矿问题,论文从深部找矿的概念、类型、目标、效益等方面简要介绍了国外理论研究和找矿实践概况。强调深部找矿中要加强地壳深部结构的研究,要重视深部找矿的经济"回报率"和勘查项目的"转化率"的重要性。     

The automated photometric determination of total fluorine in mineral exploration

An analytical method previously applied to the determination of fluorine in rocks and minerals would seem to be ideal for exploration samples such as soils, stream sediments and vegetation. The determination which utilises the Zr-xylenol orange complex is performed on acidified leachates following sodium carbonate fusion. This digestion technique is rapid, simple and amenable to batch sample processing. The method, which is applicable to samples containing from about 10 ppm to over 3% fluorine, is essentially interference free.     

Anomalous geochemical patterns from northern Sumatra: their assessment in terms of mineral exploration and regional geology

A regional stream sediment survey has been conducted in Sumatra north of 4°N. The survey area is approximately 38,000 km² of mountainous terrain mostly covered by dense tropical rainforest. The overall sample density achieved by the survey was one per ten km². However, the difficult terrain and thick vegetation blanket have meant that a uniform sample density was not obtained. The uneven sample density has presented problems with interpretation of the geochemical patterns and identification of anomalous areas for mineral exploration purposes.Two methods have been designed for identifying mineral exploration targets from the geochemical results found by the survey. The first method uses computerised probability calculations and the second a simple empirical formula. Both methods appear to give similar results.Northern Sumatra has very distinct geochemical patterns. Copper shows a linear zone of high values along the axial Barisan Mountain Range, which are derived from two main sources: the Sumatran ophiolites and copper-rich calc-alkaline intrusives. High chromium values also occur not only over the ophiolites, but also over placers derived from them. High lead values are grouped to the east of the linear copper zone and they border the oil and gas basins of the eastern coastal strip. High tin values occur west of the copper rich intrusives, but east of the present-day subduction zone off the west coast of Sumatra. The overall pattern fails to conform to the classic zonation of mineral deposits across a simple subduction system, perhaps because large transcurrent faults have sliced northern Sumatra into blocks and so brought blocks of different provenance into contact. This explanation is confirmed by the lithium distribution, which reveals two wholly distinct provinces astride the Sumatran Fault System.     

市场经济条件下的商业性矿产资源勘查工作

矿产资源是经济建设和社会发展的重要基础,地质勘查工作是经济社会发展的重要基础工作,公益性勘查和商业性勘查双轨制地勘体制为矿业权市场的建立创造了条件。地质勘查工作具有基础性、长期性、前瞻性和风险性等特点,为使矿业权市场健康平稳的发展,国家在鼓励商业性勘查的前提下,必须制定相关的政策扶持商业性矿产勘查,同时还要改善商业性矿产勘查市场环境,维护好勘查市场秩序,强化矿业权管理,保护矿业权人的合法权益,依法查处勘查中违法活动。     

Remote sensing for mineral exploration

Remote sensing is the science of acquiring, processing, and interpreting images and related data, acquired from aircraft and satellites, that record the interaction between matter and electromagnetic energy. Remote sensing images are used for mineral exploration in two applications: (1) map geology and the faults and fractures that localize ore deposits; (2) recognize hydrothermally altered rocks by their spectral signatures. Landsat thematic mapper (TM) satellite images are widely used to interpret both structure and hydrothermal alteration. Digitally processed TM ratio images can identify two assemblages of hydrothermal alteration minerals; iron minerals, and clays plus alunite. In northern Chile, TM ratio images defined the prospects that are now major copper deposits at Collahuasi and Ujina. Hyperspectral imaging systems can identify individual species of iron and clay minerals, which can provide details of hydrothermal zoning. Silicification, which is an important indicator of hydrothermal alteration, is not recognizable on TM and hyperspectral images. Quartz has no diagnostic spectral features in the visible and reflected IR wavelengths recorded by these systems. Variations in silica content are recognizable in multispectral thermal IR images, which is a promising topic for research.     

Geochemistry of tin, tungsten and molybdenum in Swedish proterozoic granitoids: Their potential use in regional mineral exploration

The primary aim of this broad regional study is to statistically determine the Li-Sn-W-Mo-bearing potential of various granitoids using geochemical criteria. Computer based, univariate and multivariate statistical methods are applied to major- and trace-element data from about 660 granitic rock samples and over 800 major element analyses, selected from the Swedish geological literature. The granitoids are subdivided following earlier geotectonic chronologic and newer geochemical-statistical principles.Most granite types occurring in known Sn-W mineralized areas, except the granites around the W deposit of Baggetorp, were identified as potentially W-Sn-bearing. That is, they show significantly high mean and variance values for W and/or Sn as well as promising values of the probability parameters for these elements, compared to corresponding statistics for a calculated Swedish average granitoid (SAG).Evidence of very high total variability of Li, Sn and W within the individual granite types suggests the need for further tests, to control the variability errors due to sampling and preparation and errors of chemical analysis. These sources of error may obscure natural elemental heterogeneity of the granite type that is of interest in geochemical prospecting.Interpretations of Sn, W and Li frequency distribution patterns, petrochemical trends and multivariate similarity tests suggest that the primary chemistry of the granitoids is overprinted by (a) postmagmatic processes of broad regional nature, which have similarly affected the individual granite types, and (b) a wide variety of secondary alterations of local character. These conclusions imply that potential Sn and W deposits may be sought within all Swedish Proterozoic granitoids and their within all Swedish Proterozoic granitoids and their immediate sorroundings, where susch processes have redistributed and concentrated these where such processes have redistributed and concentrated these elements. However, the granites which are highly differentiated, Sn-W-Li-U-Th-F-enriched, and strongly and strongly magnetic are particularly promising target areas for further, extensive rock-geochemical prospecting and other exploration surveys. rock-geochemical prospecting and other exploration surveys.     

Mathematical models for mineral exploration

This papers shows a method whereby different factors and aspects of exploration can be transformed into mathematical models. Selected examples illustrate the procedures followed. Decisions on the basis of uncertain objectives have to be made long before the observations in the field can be started. In a pattern recognition phase, criteria are extracted and characterized on the basis of more or less representative, random samples collected in the surroundings of known mineral deposits. It is not certain the geological model of this training area can be transposed to the prospective areas. In a preparation and planning phase, it has to be proved whether or not a balanced and controlled risk can be expected from a fixed sampling design, the choice of criteria, and the accuracy of measurements performed. By applying mathematical techniques the quality of the decision making can be optimized. In special studies, the probability of design in the vicinity of the undiscovered deposit can be estimated from the observations and the quality of estimation can be controlled in an accurate way.     

关于商业性矿产地质勘查工作的几点认识

随着矿业权市场的逐步开放,民营资本甚至国外资本参与矿产资源风险勘查的力度逐年增加,这在一定程度上激活了商业性矿产地质勘查市场,为地勘单位的发展带来了更多的机遇。但同时,由于投资主体的不同,商业性矿产地质勘查项目在勘查目的、勘查周期、勘查阶段划分以及施工安排上,与我们以往的计划性勘查项目有了明显的不同。笔者根据近年的工作实际,就商业性矿产地质勘查工作谈一下自己的看法。1商业性矿产地质勘查的特点商业性矿产地质勘查工作同其他地质勘查工作一样,都必须按地质规律开展工作,但就具体工作而言,商业性矿产地质勘查工作又有…     

江西有色地勘局稀土矿产勘查回顾

江西有色地勘局稀土矿产勘查始于1968年,经历了稀土查定、单矿物型稀土勘查和离子吸附型稀土勘查三个阶段.后阶段同时开创我局联营办矿和地质市场服务的先例.获得了一定的地质效果和地质研究成果.按稀土元素配分特点划分轻、重和中钇富铕三个稀土配分类型,为选择利用提供依据.