基于BIF条带状铁建造矿化特征的国际铁矿石盈亏平衡运营成本定量研究

国内外铁矿石价格对标基准多采用离岸价或到岸价,而非盈亏平衡运营成本,难以揭示我国铁矿石所面对的真实市场承压价格。为了厘清国际一线生产商的铁矿石盈亏平衡运营成本价格,本文对世界上最重要的条带状铁建造(BIF)矿产地——西澳哈默斯利盆地高品位赤铁矿矿床的矿化特征及代表性铁矿石产品展开系统研究,同时引入巴西铁四角地区的铁英岩型赤铁矿矿石作为对照,分析全球典型高品位赤铁矿矿石经济指标。结合前人研究成果,将西澳哈默斯利盆地与BIF相关的高品位赤铁矿的富集矿化类型划分为假象赤铁矿-针铁矿、微板状赤铁矿与河道沉积型赤铁矿,巴西铁四角主要为铁英岩型赤铁矿。上述各矿化类型对应的铁矿石产品的铁元素含量均高于56%;在杂质元素含量上,假象赤铁矿-针铁矿的磷含量高,微板状赤铁矿的磷、硫含量较高,河道沉积型赤铁矿的磷、硫含量较低,铁英岩型赤铁矿含锰。经定量估算,西澳力拓、必和必拓、FMG和巴西淡水河谷的铁矿石盈亏平衡运营成本价格分别为34.66、36.76、47.35、38.07美元/干吨,可为中国海外权益铁矿项目开发提供运营成本的参考。     

西澳皮尔巴拉地区鲸背山铁矿床地质特征与形成规律

澳大利亚是全球铁矿石的生产大国,也是我国铁矿石的主要进口国。其铁矿主要产于西澳洲皮尔巴拉克拉通的哈默斯利省,与前寒武纪的条带状含铁建造(BIF)有关。对位于皮尔巴拉南部纽曼镇附近的世界上最大的露天铁矿山——鲸背山(Mt Whaleback)铁矿的形成背景、矿体特征及成因进行了总结。矿体产于哈默斯利群布洛克曼含铁建造中,矿体东部走向北东,西部走向近东西,总长度5 000余米。矿体在地表出露最宽处达600余米,一般200m;矿体向下延深最深达500m。主要矿石矿物为微板状赤铁矿和假象赤铁矿,还有少量针铁矿,基本不含磁铁矿。矿石基本没有磁性。围岩蚀变作用主要有:去硅化、高岭土化、赤铁矿化和碳酸盐化。元素地球化学、氧同位素和围岩蚀变等研究表明,鲸背山铁矿床属于热液改造型铁矿,其形成过程主要受原始矿源层BIF、正断层和热液流体等控制,使得BIF中的脉石矿物迁出,铁不断得到富集,从而形成高品位的铁矿床。由于西澳哈默斯利省面积大,含BIF的地层分布范围广,地质工作程度较低,因此该区隐伏铁矿找矿潜力依然较大。     

西澳大利亚州铁矿分布规律及矿床成因分析

西澳大利亚州铁矿资源主要分布在北部皮尔巴拉和南部的伊尔岗两个太古宙克拉通。皮尔巴拉克拉通BIF型铁矿在汤姆普赖斯山、恰那和布鲁克曼的矿石矿物组合为假象赤铁矿一微板状赤铁矿,马拉曼巴的为赤铁矿一针铁矿,CID型铁矿在罗布河和杨迪矿石类型主要为褐铁矿;伊尔岗克拉通BIF型铁矿在库里阿诺的矿石矿物组合为针铁矿一假象赤铁,比温和曼迪尕的为磁铁矿±假象赤铁矿和针铁矿±赤铁矿。BIF型铁矿为浅生一变质成矿,而CID型铁矿则是先前形成的BIF经侵蚀、搬运、沉积和埋藏作用形成。     

澳大利亚西部哈默斯利铁成矿省BIF富铁矿的成矿特征与控矿因素

澳大利亚西部哈默斯利铁成矿省含有世界级高品位的赤铁矿体。主要铁矿床包括芒特维尔贝克、汤姆普莱斯山、帕拉伯杜等,它们均产于元古宙早期布罗克曼BIF型含铁建造中。高品位铁矿体的空间分布明显受到元古宙区域隆起和拉张环境下形成的古老正断层系统的控制。该成矿省高品位铁矿层的形成可分为3个阶段:第1阶段为深层阶段,该阶段硅从含铁建造中淋滤出来,留下薄层状富含铁氧化物、碳酸盐岩、硅酸镁和磷灰石的残余物;第2阶段为深部大气水氧化阶段,该阶段含铁建造的磁铁矿—菱镁矿组合被氧化为赤铁矿—铁白云石,并以发育假象赤铁矿为特征;第3阶段为浅层风化作用。通过对成矿特征和成矿模式的总结,认为成矿时代、断层、褶皱等构造特征及流体和表生风化作用是富铁矿床形成的主要控矿因素。     

澳大利亚西部哈默斯利铁成矿省BIF富铁矿的成矿特征与控矿因素

澳大利亚西部哈默斯利铁成矿省含有世界级高品位的赤铁矿体。主要铁矿床包括芒特维尔贝克、汤姆普莱斯山、帕拉伯杜等,它们均产于元古宙早期布罗克曼BIF型含铁建造中。高品住铁矿体的空间分布明显受到元古宙区域隆起和拉张环境下形成的古老正断层系统的控制。该成矿省高品位铁矿层的形成可分为3个阶段：第1阶段为深层阶段,该阶段硅从含铁建造中淋滤出来,留下薄层状富含铁氧化物、碳酸盐岩、硅酸镁和磷灰石的残余物;第2阶段为深部大气水氧化阶段,该阶段含铁建造的磁铁矿-菱镁矿组合被氧化为赤铁矿-铁白云石,并以发育假象赤铁矿为特征;第3阶段为浅层风化作用。通过对成矿特征和成矿模式的总结,认为成矿时代、断层、褶皱等构造特征及流体和表生风化作用是富铁矿床形成的主要控矿因素。     

西澳大利亚中西铁矿区地质特征及找矿标志

澳大利亚是世界上铁矿石较为丰富的国家之一,已探明的铁矿石资源90%集中在西澳州哈默斯利铁成矿省和中西铁矿区。由于哈默斯利铁成矿省铁矿资源日渐枯竭,中西铁矿区已逐渐成为西澳的新兴铁矿区。基于对中西铁矿区地质特征及与世界上其它大型铁矿区(省)含铁建造成矿特征的对比,认为该矿区铁矿床的成矿类型为阿尔戈马型,太古宙的条带状含铁建造、正地形的地形地貌特征、地表分布大面积的富铁红土及磁异常是该矿区铁矿的主要找矿标志。通过对该地区投资现状的分析,提出投资建议。     

西澳大利亚中西铁矿区地质特征及找矿标志

澳大利亚是世界上铁矿石较为丰富的国家之一,已探明的铁矿石资源90％集中在西澳州哈默斯利铁成矿省和中西铁矿区。由于哈默斯利铁成矿省铁矿资源日渐枯竭,中西铁矿区已逐渐成为西澳的新兴铁矿区。基于对中西铁矿区地质特征及与世界上其它大型铁矿区（省）含铁建造成矿特征的对比,认为该矿区铁矿床的成矿类型为阿尔戈马型,太古宙的条带状含铁建造、正地形的地形地貌特征、地表分布大面积的富铁红土及磁异常是该矿区铁矿的主要找矿标志。通过对该地区投资现状的分析,提出投资建议。     

西北某喷流沉积型铁铜矿工艺矿物学研究

西北某铁铜多金属矿床规模大,具有铁、铜、金、铅锌等多金属矿化,属于海底喷流沉积型矿床。笔者采用工艺矿物学研究方法,查明了矿石工艺矿物学特性。研究结果表明,矿石的组成矿物种类较为复杂,铁矿物主要是磁铁矿、半假象―假象赤铁矿和菱铁矿,其次为赤铁矿,铜矿物主要包括黄铜矿和斑铜矿。矿石中铁矿物和铜矿物均具不均匀细粒―微细粒嵌布特征;通过选矿可获得铜精矿和铁精矿。     

关于变质岩铁矿的古风化型富铁矿矿床

由前寒武系含铁硅质岩(含铁石英岩)经表生氧化、淋滤、去硅作用形成的赤铁矿矿床,在世界各大洲均有发现.这一类型铁矿床,具有矿石含铁品位高(有的几乎接近纯赤铁矿理论值)、含杂质少、矿床规模大、埋藏一般很浅等特点,其工业价值明显地高于含铁石英岩,早已是世界铁矿石主要来源之一.近年来,在巴西卡腊贾斯和澳大利亚的哈默斯利发现了这一类型铁矿床的特大型矿床,特别是哈默斯利的发现,使澳大利亚从一个铁矿资源不足的国     

澳洲铁矿床研究现状及存在的问题??

澳大利亚是世界上铁矿石资源最为丰富的国家之一,其铁矿床主要产在西澳皮尔巴拉地区,有三种类型,分别是:①赋存在条带状含铁建造(BIF)中的层状铁矿床(BID),②产在古河道中的河道型铁矿床(CID),和③主要由BID受侵蚀崩塌或冲积形成的碎屑型铁矿床(DID),以前两种类型为主。BID型铁矿通常品位高,规模大,是本区最为重要的矿床类型,其矿床成因尚存在争论,主要有三种观点,分别是表生—变质模式、同造山的热液模式和深成—表生模式。CID型铁矿由于其规模较大和容易开采,因此在西澳的铁矿石开采中占有很重要的地位,矿石以球粒状构造和富含铁化的木屑为主要特点。关于CID型矿床的成因,争议较大,观点甚多。一些学者认为CID型矿床的形成受特定条件(包括气候、地表风化和地质背景)的控制;而有些学者则认为CID型矿床形成于一个富含有机酸的饱和地下水的加积河道内,与铁的原位溶解和再沉淀有关。矿化发生在古地下水—大气界面,因此受地下水位的控制。由于对铁矿的矿床成因没有形成统一的认识,因此对指导找矿产生了较大影响。     

Microplaty hematite ore in the Yilgarn Province of Western Australia: The geology and genesis of the Wiluna West iron ore deposits

The Wiluna West small (~ 130 Mt) high-grade bedded hematite ore deposits, consisting of anhedral hematite mesobands interbedded with porous layers of acicular hematite, show similar textural and mineralogical properties to the premium high-grade low-phosphorous direct-shipping ore from Pilbara sites such as Mt Tom Price, Mt Whaleback, etc., in the Hamersley Province and Goldsworthy, Shay Gap and Yarrie on the northern margin of the Pilbara craton. Both margins of the Pilbara Craton and the northern margin of the Yilgarn craton were subjected to sub-aerial erosion in the Paleoproterozoic era followed by marine transgressions but unlike the Hamersley Basin, the JFGB was covered by comparatively thin epeirogenic sediments and not subjected to Proterozoic deformation or burial metamorphism. The Joyner's Find greenstone belt (JFGB) in the Yilgarn region of Western Australia was exhumed by middle to late Cenozoic erosion of a cover of unmetamorphosed and relatively undeformed Paleoproterozoic epeirogenic sedimentary rocks that preserved the JFGB unaltered for nearly 2 Ga; thus providing a unique snapshot of the early Proterozoic environment.Acicular hematite, pseudomorphous after acicular iron silicate, is only found in iron ore and BIF that was exposed to subaerial deep-weathering in early Paleoproterozoic times (pre 2.2 Ga) and in the overlying unconformable Paleoproterozoic conglomerate derived from these rocks and is absent from unweathered rocks (Lascelles, 2002). High-grade ore and BIF weathered during later subaerial erosion cycles contain anhedral hematite and acicular pseudomorphous goethite. The acicular hematite was formed from goethite pseudomorphs of silicate minerals by dehydration in the vadose zone under extreme aridity during early Paleoproterozoic subaerial weathering.The principal high-grade hematite deposits at Wiluna West are interpreted as bedded ore bodies that formed from BIF by loss of chert bands during diagenesis and have been locally enriched to massive hematite by the introduction of hydrothermal specular hematite. No trace of chert bands are present in the deep saprolitic hematite and hematite–goethite ore in direct contrast to shallow supergene ore in which the trace of chert bands is clearly defined by goethite replacement, voids and detrital fill. Abundant hydrothermal microplaty hematite at Wiluna West is readily distinguished by its crystallinity.The genesis of the premium ore from the Pilbara Region has been much discussed in the literature and the discovery at Wiluna West provides a unique opportunity to compare the features that are common to both districts and to test genetic models.     

The Major Ore Clusters of Super-Large Iron Deposits in the World,Present Situation of Iron Resources in China,and Prospect

Abstract: The metamorphosed sedimentary type of iron deposits (BIF) is the most important type of iron deposits in the world, and super-large iron ore clusters of this type include the Quadrilatero Ferrifero district and Carajas in Brazil, Hamersley in Australia, Kursk in Russia, Central Province of India and Anshan-Benxi in China. Subordinated types of iron deposits are magmatic, volcanic-hosted and sedimentary ones. This paper briefly introduces the geological characteristics of major super-large iron ore clusters in the world. The proven reserves of iron ores in China are relatively abundant, but they are mainly low-grade ores. Moreover, a considerate part of iron ores are difficult to utilize for their difficult ore dressing, deep burial or other reasons. Iron ore deposits are relatively concentrated in 11 metallogenic provinces (belts), such as the Anshan-Benxi, eastern Hebei, Xichang-Central Yunnan Province and middle-lower reaches of Yangtze River. The main minerogenetic epoches vary widely from the Archean to Quaternary, and are mainly the Late Archean to Middle Proterozoic, Variscan, and Yanshanian periods. The main 7 genetic types of iron deposits in China are metamorphosed sedimentary type (BIF), magmatic type, volcanic-hosted type, skarn type, hydrothermal type, sedimentary type and weathered leaching type. The iron-rich ores occur predominantly in the skarn and marine volcanic-hosted iron deposits, locally in the metamorphosed sedimentary type (BIF) as hydrothermal reformation products. The theory of minerogenetic series of mineral deposits and minerogenic models has applied in investigation and prospecting of iron ore deposits. A combination of deep analyses of aeromagnetic anomalies and geomagnetic anomalies, with gravity anomalies are an effective method to seeking large and deep-buried iron deposits. China has a relatively great ore-searching potential of iron ores, especially for metamorphosed sedimentary, skarn, and marine volcanic-hosted iron deposits. For the lower guarantee degree of iron and steel industry, China should give a trading and open the foreign mining markets.     

Opaque mineralogy and magnetic properties of selected banded iron‐formations,Hamersley Basin,Western Australia

The oxide mineralogy and rock magnetic properties of unmineralised banded iron‐formations in selected portions of four drillholes in the Hamersley Basin, Western Australia are reviewed. In all four drillholes, petrographic studies indicate that primary euhedral to subhedral hematite is partially replaced by magnetite as a result of subsolidus reduction. All drillholes show partial recrystallisation of the secondary magnetite, suggesting that early subsolidus reduction was probably a regional event occurring during prograde metamorphism. Incomplete replacement of primary hematite by magnetite within and between sedimentary band structures indicates that equilibration in the magnetite stability field was not reached even at the mesoband scale. Subsequent subsolidus oxidation of magnetite and the formation of a second‐generation hematite are documented in only two of the drillholes. Goethite‐filled veins and thick selvages of goethite around some veins reflect movement of circulating oxidising fluids. The absence of goethite and second‐generation hematite in two of the drillholes indicates that subsolidus oxidation is not a regional event, but very much localised. Rapid changes in down‐hole susceptibility measurements correlate directly with detailed petrographic results as susceptibility readings change with the hematite/magnetite ratio on a mesoband scale. Acquisition of the main remanence correlates with the formation of hematite as the primary oxide phase followed by partial replacement by magnetite as a result of subsolidus reduction, supporting regional models requiring pre‐folding remanence. The strong orientation of the primary hematite parent parallel to band structures in the banded iron‐formations has influenced the direction of crystallisation remanent magnetisation during subsolidus reduction to the magnetite daughter. The strong planar alignment has also produced a planar magnetic fabric and marked anisotropy of magnetic susceptibility. A natural remanent magnetisation overprint and reduction in anisotropy of magnetic susceptibility are only recorded in samples that have undergone subsolidus oxidation and the recognition of localised post‐metamorphic oxidation overprinting can also explain ore deposit models requiring post‐folding remanence. The relative timing of and between oxidising fluid events is not known, but both petrographic and rock magnetic evidence to date suggests that there was at least one and probably two post‐folding oxidising events in the area of study.     

几内亚福雷卡里亚YML铁矿区的富铁矿床地质特征及找矿前景探讨

YML铁矿区位于几内亚福雷卡里亚省,富铁矿以条带状赤铁矿和铁角砾岩矿为主。矿区内共发育7条矿体,条带状赤铁矿体6条,铁角砾岩矿体1条。条带状赤铁矿体赋存部位多为向形地段,次级紧密褶皱发育,沿走向和倾向有逐渐变薄和尖灭的趋势;铁角砾岩矿体覆盖于地表,以风化壳的形式出现。矿床类型属复合类型,即海底热液喷气沉积叠加后期构造变质型+风化淋滤型。该区具备铁矿形成和保存的地质条件,且已发现具一定储量、品位较高的条带状赤铁矿和大面积的铁角砾岩分布区,区内铁矿找矿远景较好。     

论中生代岩浆活动对海南石碌富铁矿床的改造作用

石铁矿位于海南省昌江县境内,是中国最大的富铁矿床.该矿区及其周边中生代侵入岩广泛发育,岩浆活动对矿床影响强烈,其结果主要产生两类改造型矿石,即石榴子石磁铁矿矿石和黄铁矿磁铁矿赤铁矿矿石.通过对改造型矿石的矿相学研究、矿石及矿物的硫同位素和微量元素分析,表明改造型矿石中的赤铁矿发生了磁铁矿化,其中的硫主要来源于岩浆,而铁...     

Genesis modelling for the Hamersley BIF-hosted iron ores of Western Australia: a critical review

Enrichment iron ore of the Hamersley Province, currently estimated at a resource of over 40 billion tonnes (Gt), mainly consists of BIF (banded iron-formation)-hosted bedded iron deposits (BID) and channel iron deposits (CID), with only minor detrital iron deposits (DID). The Hamersley BID comprises two major ore types: the dominant supergene martite–goethite (M-G) ores (Mesozoic–Paleocene) and the premium martite–microplaty hematite ores (M-mplH; ca 2.0 Ga) with their various subtypes. The supergene M-G ores are not common outside Australia, whereas the M-mplH ores are the principal worldwide resource. There are two current dominant genetic models for the Hamersley BID. In the earlier 1980–1985 model, supergene M-G ores formed in the Paleoproterozoic well below normal atmospheric access, driven by seasonal oxidising electrochemical reactions in the vadose zone of the parent BIF (cathode) linked through conducting magnetite horizons to the deep reacting zone (anode). Proterozoic regional metamorphism/diagenesis at ～80–100°C of these M-G ores formed mplH from the matrix goethite in the local hydrothermal environment of its own exhaled water to produce M-mplH ores with residual goethite. Following general exposure by erosion in the Cretaceous–Paleocene when a major second phase of M-G ores formed, ground water leaching of residual goethite from the metamorphosed Proterozoic ores resulted in the mainly goethite-free M-mplH ores of Mt Whaleback and Mt Tom Price. Residual goethite is common in the Paraburdoo M-mplH-goethite ores where erratic remnants of Paleoproterozoic cover indicate more recent exposure.

Deep unweathered BIF alteration residuals in two small areas of the Mt Tom Price M-mplH deposits have been used since 1999 for new hypogene–supergene modelling of the M-mplH ores. These models involve a major Paleoproterozoic hydrothermal stage in which alkaline solutions from the underlying Wittenoom Formation dolomite traversed the Southern Batter Fault to leach matrix silica from the BIF, adding siderite and apatite to produce a magnetite–siderite–apatite ‘protore.’ A later heated meteoric solution stage oxidised siderite to mplH + ankerite and magnetite to martite. Weathering finally removed residual carbonates and apatite leaving the high-grade porous M-mplH ore. Further concepts for the Mt Tom Price North and the Southern Ridge Deposits involving acid solutions followed, but these have been modified to return essentially to the earlier hypogene–supergene model. Textural data from erratic ‘metasomatic BIF’ zones associated with the above deposits are unlike those of the typical martite–microplaty hematite ore bodies. The destiny of the massive volumes of dissolved silica gangue and the absence of massive silica aureoles has not been explained. Petrographic and other evidence indicate the Mt Tom Price metasomatism is a localised post-ore phenomenon. Exothermic oxidation reactions in the associated pyrite-rich black shales during post-ore removal by groundwater of remnant goethite in the ores may have resulted in this very localised and erratic hydrothermal alteration of BIF and its immediately associated pre-existing ore.     

Mineralogical Characteristics of Iron Ores in Joda and Khondbond Areas in Eastern India with Implications on Beneficiation

Precambrian iron ores of the Singhbhum-North Orissa region occur in eastern India as part of the Iron Ore Group (IOG) within the broad horse-shoe shaped synclinorium. More than 50% of Indian iron ore reserves occur in this region. Massive-hard, flaky-friable, blue dust and lateritic varieties of iron ores are the major ore types, associated with banded hematite, jasper and shales. These ores could have formed as a result of supergene enrichment through gradual but extensive removal of silica, alumina and phosphorus from banded iron formations and ferruginous shale. Attempts for optimal utilization of these resources led to various ore characterization studies using chemical analysis, ore and mineral petrography, XRD analysis, SEM and electron probe micro analysis (EPMA). The ore chemistry indicates that the massive hard ores and blue dust have high iron, low alumina and phosphorus contents. Because of high quality, these ores do not require any specialized beneficiation technique for up-gradation. However, flaky-friable, lateritised and goethitic ores are low in iron, high in alumina and phosphorus contents, requiring specific beneficiation techniques for up-gradation in quality. XRD, SEM and ore microscopic studies of massive hard ores indicate the presence of hematite and goethite, while flaky and lateritic ores show a higher concentration of goethite, kaolinite, gibbsite and hematite. EPMA studies show the presence of adsorbed phosphorous as fine dust in the hard ores. Sink and float studies reveal that most of the gangue minerals are not completely liberated in the case of goethitic and lateritic ores, even at finer fractions.     

Carbonate alteration of the Upper Mount McRae Shale beneath the martite-microplaty hematite ore deposit at Mount Whaleback, Western Australia

The formation of large martite-microplaty hematite ore deposits in northwest Australia remains a contentious topic in part because important evidence supporting a unifying genetic model has not been observed at all deposits. Carbonate replacement of silica has been found along normal faults below ore at the Mount Tom Price and Giles Mini deposits, which suggests an early hypogene process during ore formation. However, such rocks have not been identified at the largest martite-microplaty hematite deposit, Mount Whaleback. In this study, samples of the Mount McRae Shale are examined for their chemistry, mineralogy and petrography. These samples were collected from several key locations, including an area that immediately underlies ore along the Mount Whaleback fault at Mount Whaleback. Compared to unaltered black Mount McRae Shale from Wittenoom Gorge in the north and altered black and red Mount McRae Shale at Mount Whaleback, reddish-green Mount McRae Shale along the Mount Whaleback fault is greatly enriched in MgO and CaO and depleted in SiO₂. This chemistry arises from significant amounts of fine- to medium-grained ferroan-dolomite and ankerite and cross-cutting chlorite and carbonate veins. The composition is distinct from that produced during regional metamorphism, and most likely represents hydrothermal alteration after metamorphism. The lack of carbonate-rich, silica-poor rocks in the overlying Dales Gorge Member at Mount Whaleback is consistent with pervasive oxidation of most rocks in the region during or after ore genesis, a process that removed carbonates. Although several questions remain unanswered, these results support models that invoke an early hypogene stage during the formation of the martite-microplaty hematite deposits in the Hamersley Province.Editorial Handling: B. Lehmann