High-Grade Iron Ore Grade Iron Ore
Transcrição
High-Grade Iron Ore Grade Iron Ore
5/15/2009 High--Grade Iron Ore High Characteristics and Genetic Models Important Deposits in the World Continent Region Damara Belt, Namíbia Africa Transvaal-Griquatown, SA Liberian Shield, Liberia-Sierra Leona Oceania Middleback Range, Austrália Hammersley Altai, W-Sibéria Eurasia Krivoy Rog Bihar – Orissa, India Grupo Rapitan – NW-Canada North America Lake Superior Labrador, Canada Isua, Grönland Urucum/ Mutum, Brasil – Bolivia South America QF, Minas Gerais, Brazil Carajás, Pará – Brasil 1 5/15/2009 High--Grade Iron Ore High Fetotal > 64% SiO 2 3-4% Al2O3 < 1% K2O + Na2O < 0.1% P < 0.05% S < 0.1% Mineralogy •Magnetite/Martite/Magemite •Hematite/Specularite •Goethite and other Fehydroxides High--Grade Iron Ore High Banded Ore 2 5/15/2009 High--Grade Iron Ore High Brecciated Ore High--Grade Iron Ore High Brecciated Ore 3 5/15/2009 High--Grade Iron Ore High Schistose Ore High--Grade Iron Ore High Related Processes Carbonate alteration Oxidation Metassomatism Laterization 4 5/15/2009 Carbonate Alteration in Fault Zone Carajas N4E Carbonate alteration 5 5/15/2009 N4E Carbonate alteration HD Cb Cb 750 µm Carbonate alteration Hm Cb Mt Sample N4E/F603/P38,6 750 µm Cb400 µm 750 µm Carajas N4E H m Cb Mt 400 µm 400 µm 6 5/15/2009 Carajas N4E Carbonate alteration Minérios de Ferro de Alto Teor Quartz and Carbonate Leaching 7 5/15/2009 22. 5 20 17. 5 Al2O3 15 12. 5 10 7.5 BIF 5 ma gnetite -ca rbonate (e nri ched BIF) high-P hematite mineralisation 2.5 high-P ma gnetite m inera lis ation Ratio of immobile elements remains constant throughout the entire enrichment process low-P hem atite ore 0 0 .2 .4 .6 .8 1 1.2 TiO2 High-grade ore from dolomitic itabirite Oxidation 8 5/15/2009 The Anoxic Oxidation Crystalline Structure of Magnetite and Hematite The Anoxic Oxidation 9 5/15/2009 Anoxic Oxidation and Hydration Carbonates 10 5/15/2009 11 5/15/2009 Mt. Tom Price Reservas = 200 Mt (2001) Strip ratio = 0.9:1 Structural Control of Deposits Brittle Environment 4 West Basal Fault 4 East Basal Fault MMG BRQ 12 5/15/2009 A FAULT D 55 65 50 0 50 4 West 60 23 East 40 2 3 EAST 4 East C 30 G Upper Lower Hamersley Group Fortescue Group 30 Eastern Ranges T UL FA Wyloo Group HO LE 30 35 Legend 5 km 35 IES W HO T UL FA 45 BAS AL 65 ST EA 18 11 West MT McGRATH FORMATION McGrath unconformity BEASLEY RIVER FORMATION BQ unconformity WOONGARRA RHYOLITE WEELI WOLLI FORMATION BROCKMAN IRON FORMATION Joffre Member Whaleback Shale Member Dales Gorge Member WITTENOOM, MT SYLVIA, MCRAE FORMATIONS CH AN NA R 25 25 64 East 15 6 EA ST Channar FA UL T Steep Reverse Fault B Steep Normal Fault Range Parallel Fault Oblique Fault MARRA MAMBA FORMATION JEERINAH FORMATION Hematite Conglomerate BIF AND INTRUSIVE ROCKS extension dolomite below BIF separated by shale BIF SHALE HEMATITE CONGLOMERATE CARBONATE IRON ORE VOLCANIC ROCKS HEMATITE/ MAGNETITECARBONATE PROTORE uplift and erosion supergene upgrade of protores to high-grade ores Brockman I.F. hematite deposits thrusting and folding dolomite above BIF deep supergene circulation in thrusts and folds Marra Mamba hematite-goethite deposits 13 5/15/2009 N4E 14 5/15/2009 Structural Control of Deposits Ductile Environment 15 5/15/2009 16 5/15/2009 A Word about the Syngenetic Models (Chamberlin 1883, King 1974, Lascelles 2006) GENESIS OF BIF A: Deposition of proto-iron formation as nontroniteFe-hydroxide turbiditic mud Fe-hydroxide Nontronite B: Breakdown of nontronite to Fe-oxide and colloidal silica C: Settling of Fe-oxide Fe-oxide Silica NONTRONITE: Ca.5(Si7A l.8F e.2) ( F e3.5 A.4l M g.1 ) O20 (OH)4 Source: Lascelles 2006 Earthquake!!! D: De-watering and escape of silica leads to localized formation of chert-free BIF H2O H2 O + SiO 2 Cherty BIF Chert-free BIF H2O Cherty BIF E: Erosion exposes chert-free BIF, supergene processes form weathered cherty BIF and hematite or hematite-goethite ore Cherty BIF (weathered) Hematite-goethite ore Source: Lascelles 2006 17 5/15/2009 Evidences? Chert Cover? 4cm Fe-Oxide “Vein” Previsions and Evidences (?) Primary bodies below the weathering zone (mt/hem-carbonate-silicates ) No surface evidence of high-grade orebodies No relation to tectonic structures SiO2/Chert cover 18 5/15/2009 Supergene Ore Bown Ores Structure Weathering surface Meteoric waters (per descensum). Residual concentration or substitution Structural control (great depths) Prä-metamorphic (hard ores) •Friable “soft” ore down to great depths. •Related to Hard orebodies •Related to weathering surfaces •Commonly related to carbonatic bodies •Oxidized/hydrated mineralogy •Substitution of SiO2 by goethite Supergene Ores 19 5/15/2009 Supergene Ores 20mm GMF (Marandoo) (Goethita - Martita) Paraburdoo H2F (Paraburdoo) Group B (Microplaty hematite dominant) Hematita lamelar – Goethita 20mm GOL (Nammuldi) Namuldi Group D (Goethite) (Goethite) 20mm Brockman HGF (Brockman No.2 Pit 4) Group C (Hematite - goethite) Hematita - Goethita Paraburdoo Western Ranges Wyloo unconformity BIF com forte mergulho BIF em profundidade Hematita microlamelar Zonas de permeabilidade elevada 20 5/15/2009 Sishen Deposit Example of a Paleokarst SISHEN MIDDLE MINE E W Legend KALAHARI GROUP POSTMASBURG GROUP Volcanic rocks Thrust OLIFANTSHOEK S.GROUP Quartzite Flagstone GHAAP GROUP 200m Shale Iron Formation Hematite conglomerate Chert breccia Dolerite dike Dolomite Hematite ore Unconformity Source: Kumba Sishen Deposit Ore BIF Manganese marker Dolomite 0 2 km Source: Kumba 21 5/15/2009 Hypogene Ore Bedding -controlled Tectonic control Blue Ore Soft Ore •Banded •Schistose •Granular (Blue Dust) Hard Ore •Banded •Massiv •Schistose Hydrothermal fluids (per ascensum) of different origins. i. Leaching of SiO2 and Carbonates ii. Fe-remobilization and concentration possible metassomatic substitution of gangue minerals. HM Jp HM Discordant bodies Pseudomorphosis. Reproduction of BIF-structures Precipitation of Fe-minerals in vugs 22 5/15/2009 23 5/15/2009 Hypogene Ore Hipogênicos X-tmas Tree 24 5/15/2009 High--Grade Iron Ore Veins High JP HM HD Hypogene/Supergene Hypogene /Supergene Ores 25 5/15/2009 Hypogene/Supergene Hypogene /Supergene Ores • Urucum • Mt Tom Price • Sandur SB • Maremane Dome • Thabazimbi • Carajas + Nauga East (magmatic hydrothermal) Geohemistry of Fe ore Hypogene/Supergene Hypogene /Supergene 26 5/15/2009 Supergene Deposits - Enrichment of LREE Enrichment of LREE is observed for all supergene high-grade iron ore types Mobilization of HREE in weathering profiles, and concentration of LREE in the residue, has been documented for modern environments (Nelson et al., 2003; Braun et al., 1990). The effect is related to the preferential complexation and mobilization of HREE in low temperature environments REE vs. av. Lake Superior BIF Empovreshment in Y e Yb REE Hydrotermal Hypogene Deposits Hydrothermal deposits show either no or only moderate enrichment that is uniform for all REE). (suggest simple residual enrichment) A net introduction of REE may be envisaged in this example, possibly by high salinity hydrothermal fluids HREE would have been transported more effectively than LREE (Humphris, 1984). 27 5/15/2009 REE vs. host BIF Hydrotermal Hypogene Deposits à Nauga East and Thabazimbi – consistente à SSB – enriquecimento uniform -Sm and Tm artefatos à Carajas – enriquecimento moderado em HREE, Y anômalo REE from some Carajás oresasmples 100 100 enrichment of LREE & HREEE Amostra/Condrito 10 1 .1 La Pr Ce Nd Amostra/Condrito Amostra/Condrito ETRL enrichment Eu Tb Ho Tm Lu Sm Gd Dy Er Yb 10 1 .1 La Pr Ce Eu Nd Sm Tb Gd Ho Dy Er Tm Lu Yb N5E ( 2 amostras ) N5E N5E (1 amostra, ? do padrão geral) Condrite normalized Blue squares av. archean Isua BIF, Groenland 28 5/15/2009 Amostra/Condrito 100 N4W N5E Jps Jps N5E ( 2 samples ) 10 N5E N1 1 mafic rock N4E & 1 ore N1 1 N5E (1 anomaous sample) N4E (no Cb) .1 N4E (with Cb) ( 2 samples ) La Pr Ce Eu Nd Sm Tb Gd Ho Dy Tm Lu Er Yb Minérios Amostra/Condrito 100 (B) (B) 10 1 .1 La Pr Ce Eu Nd Sm Tb Gd Ho Dy Tm Er Lu Yb Australian Hypogene Model Taylor et al. (2001) 29 5/15/2009 Australian Hypogene Model Hypogene Stage Taylor et al. (2001) Normal fault Magnetite-carbonateapatite protore • • Removal of SiO2 Mg/ Fe alteration in the diabase and shales BIF Dolomite Hydrothermal (alkaline) fluids high salinity P xT Hot (110-250oC), highly saline ascending fluids Deep Circulation of Meteoric Waters Microplaty hematite +/Hydrothermal (oxidized) fluids ankerite/dolomite low salinity Oxidation of magnetite in martite Hematite (carbonate)P remains apatite protore Magnetite-carbonateapatite protore BIF Dolomite Dolomite dissolution PxT Hot, low-saline fluids (150-450o C), Per descensum? (Taylor et al. 2001) Paraburdoo: 120-150o C (Thorne 2007) 30 5/15/2009 Weathering low-- temp meteoric fluids low meteoric fluids Hematite ore Depth of weathering Hematite (carbonate) apatite protore Magnetite (carbonate) apatite protore Removal of apatite Removal of remaining CaO and MgO from the shales Map Area WESTERN AUSTRALIA 0 400 800 Metres Fault Dolerite Dyke Colluvium Canga Hematite-goethite Hematite BROCKMAN IRON FORMATION Joffre Member Whaleback Shale Member Dales Gorge Member MT MCRAE SHALE MT SYLVIA FORMATION WITTENOOM FORMATION MARRA MAMBA FORMATION FORTESCUE GROUP Mount Wall Deposit 31 5/15/2009 Mount Wall Deposit B A DDHWLT08 DDHWLT01 ek Cre ault rn F rthe No da lgee lt Boo Fau Depth of Weathering DDHWLT02 DDHWLT07 DDHWLT05 proj. DDHWLT09 proj. Fault Dolerite Dyke 0 100 200 Metres Hematite/ magnetite-carbonate Hematite (goethite) BROCKMAN IRON FORMATION Joffre Member Whaleback Shale Member Dales Gorge Member MT MCRAE SHALE MT SYLVIA FORMATION WITTENOOM FORMATION MARRA MAMBA FORMATION FORTESCUE GROUP Carbonate Alteration in Fault Zone 32 5/15/2009 G Microplaty Hematite /goethite mpH P 0.1 mm Mt Mt/H 0.1 mm H Magnetite/martite-hematite C 0.1 mm Magnetite/ hematite-carbonates Distribution of major BIF-hosted iron ore deposits When applying a 55 wt % Fe cut-off grade the Indian iron ore resources have been reported to be ca. 25.24 billion tons with 14.63 billion tons of hematite-rich ore and 10.61 billion tons of magnetite-rich ore (Sharma, 2007). 33 5/15/2009 Hard Ore BIF DAITARI IRON ORE DEPOSIT, SOUTHERN IOG Goa ore Hard ore: magnetite 40µm Soft ore: magnetite-hematite 20µm 34 5/15/2009 ARI DONGRI DEPOSIT MAGNETITE ORE SPECULARITE ORE IN SHEAR ZONES 1 5 0µ m 150µM Ore Hauling in India 35 5/15/2009 Location of Simandou Range West-African WestCraton Kenema-Man KenemaDomain (Modified after Rocci et al., 1991) 36 5/15/2009 Ore Types Powder Biscuit Medium-Hard Hard Hematite Types 37 5/15/2009 Hematite Types Hematite 38 5/15/2009 Krivoy Rog Geological Map 39 5/15/2009 KRYVYJ RIG Crossections UKRAÏNE (I.Paranko, B. Maluk) ?2?-8 9832 20500 9813 À 22350 19829 0 16987 17752 17820 20811 1242 B Grupo Gleevatska Quartzito, conglomerado, filito. 3292 Grupo Gdancivska 339,0 Metarenito, muscovita-quartzo-biotita xisto , quartzo-sericita xisto,dolomito,marmore, formação ferrífera 750,0 1 1018,0 1238,0 1209,0 Grupo Saksaganska 2 3 Granada-cummin gtonita-clorita xisto, quartzo-biotita xisto,quartzo-clorita xisto, Formação ferrífera bandada (FFBs) 8044,0 3550,0 Grupo Skelevatska 4 Metaconglomerado, metarenito, meta-arcósio, biotita-quartzo-sericita xisto,quartzo-sericita xisto, filito, s carbonato-talco xisto,clorita-talco-anfibólio - xistos. 5 Grupo Novokrivorizka 9432,0 Metaconglomerado, metarenito, quartzo-biotita xisto, quartzo-sericita-clorita xisto,filito. 6 “Série” Konska 7 Anfibolito,Formação ferrífera bandada (FFBs), t a l c o - c a r b o n a t o - a n f i b o l i o x i s to . À Rochas graníticas (Complexo de Saksaganskiy) Cavalgamento Falha B 1256.3 Furo de sondagem Rochas graníticas e migmatíticas (Complexo de Inguletskiy) Nort e Saksagan Mineral SubSubdistricts from Kryvyj Rig Tarapako-- Lihmann Tarapako Krivoy Rog Central Inguletz (Lihman) 40 5/15/2009 KRYVYJ RIG Ore Deposits Gannivske Pervomayske mina V. Lenin mina Gvardiyska mina Juvileyna mina M. Frunze High-grade Ore Deposits Gleevatske mina Bilshovyk 8-10 million tons/ano mina Oktyabrska mina Rodina mina S. Kirova mina Gigant-Glyboka Low-Grade Ore Deposits Novokryvorizke Valyavkinske Skelevatske-Magnetitove 80-100 million tons/ano Jazida de baixo teor Jazida de alto teor Inguletsky Krivoy Rog Ore and BIFs Magnetite and silicatesilicate- carbonate carbonate-- magnetitic ores Na-Metassomatism Martite and Martíte - hematite ore Soft and hydrated ores Thickness reduction and folding BIF Hard Ore Ore BIF Porous Ore Maintainance of Thickness 41 5/15/2009 40% das reservas martitic 30% das reservas 25% das reservas criptohematítico--martítico criptohematítico specularitic-martitic 42
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