1. Iron Deposits ©2009, Dr. B. C. Paul Acknowledgement is given to the USGS,

2. The Rise of Life By 4,300,000,000 years ago the water vapor from volcanic activity had condensed into oceans By 3,800,000,000 years ago carbon isotope ratios were showing carbon sorting associated with life forms and photosynthesis –By 3,500,000,000 years ago we can see the fossils of our early Photosynthesis friends Photosynthesis means a new kid in town –Oxygen

3. The New Chemistry of Oxygen

4. The Result Banded Iron Formations

5. Time-Line of BIF 0 1,000,000,000 3,000,000,000 500,000,000 2,000,000,000 4,000,000,000 First Banded Iron Formations at about 3.8 Billion Years Ago Last around 1.8 Billion Years Ago Banded Iron formations captured 20 times the oxygen content Of the earths total atmosphere today.

6. The Disappearance of the Banded Iron Formations Photosynthesis eventually overwhelmed the dissolved iron load in the seas –Oxygen began to build noticeably in the atmosphere Iron began to oxidize on land leading to red bed rock formations

7. The Last Gasps of the Banded Iron Formations Ice Ages Last Gasps of the BIF

8. The Second Side Effect of Oxygen Early sun only produced 80% of today’s output –Earths Heat was decaying –Greenhouse gases important to the temperature Especially a powerful greenhouse gas – Methane Free oxygen in the atmosphere would oxidize and destroy methane –Great oxygen event (getting to about 0.1% to 1% O2 in atmosphere) –Ice age triggers –Snowball earth Ice sheets perhaps into the tropics with kilometer thick ice packs Both snowball episodes were associated with Banded Iron formation precipitation in reducing areas of the sea

9. Banded Iron Formations Are Large usually in precambrian shields Sizes around 200,000,000 Metric tonnes are common Big ones can be 2.4 Billion tons.

10. Iron Grades are High Around lower 50% range

11. Magnetite Fe 3 O 4 S.G. 5.1 - 5.2, Average = 5.15 Hardness 5.5-6 Color Grayish black, Iron black. Fluorescence None Magnetic Strong Iron 72.36%

12. Hematite Fe 2 O 3 Iron 69.94% S.G. 5.3 Hardness 6.5 Color Reddish gray, Black, Blackish red. Fluorescence None Magnetic becomes magnetic after heating

13. Siderite FeCO 3 S.G. 3.96 Hardness 3.5 Color Yellowish brown, Brown, Gray, Yellowish gray, Greenish gray. Fluorescence None Magnetic No Iron 48.20 %

14. Goethite FeO(OH) S.G. 3.3 - 4.3, Average = 3.8 Hardness 5-5.5 Color Brown, Reddish brown, Yellowish brown, Brownish yellow, Ocher yellow. Fluorescence None Magnetic No Iron 62.85 %

15. What New Kinds of Iron Deposits Are Available? Volcanic intrusives into continental crust have formed iron –Some are in the 1.8 to 1.3 billion year range –Many are fairly new Can produced stockworks like porphyry (different texture) Can replace beds like in some of the Lead-Zinc deposits

16. Smaller than the BIF Deposits Typical 40,000,000 metric Tonnes with big ones up To 450,000,000 tonnes.

17. Deposits Tend to be Rich – In the Upper 50s Arnold Hill USNY Benson USNY Cerro de Mercado MXCO Chador-Malu IRAN Chahehgaz IRAN Choghart IRAN Ekstromberg SWDN El Algarrobo CILE El Dorado CILE El Encino MXCO EL Romeral CILE Grangesberg SWDN Gruvberget SWDN Guadalupe & Solis MXCO Hercules MXCO Idkerberget SWDN Infiernillo CILE Joinville BRZL Kiirunavaara SWDN La Grulla MXCO La Perla-La Negra MXCO Leveaniemi SWDN Los Vasitos MXCO Luossauaara SWDN Malmberget SWDN Minarets USCA Mineville-Port Henry USNY Modarelli USNV Nakerivaara SWDN Northern Anomaly IRAN Painirova SWDN Pea Ridge USMO Ringwood USNJ Saghand IRAN Savage River AUTS Se Chakhum IRAN Sterling Lake USNY Tjarrojakka SWDN The Great Swedish Iron Ore Deposits Are this vintage

18. Last Type is the Iron Skarn Carbonate or reactive rocks Are mineralized at the Contacts with intrusives Median size is only 7.2 Million metric tonnes but Big ones can be 160,000,000 tonnes

19. Grade is about normal for Iron About 50% or so. Iron mineral of interest is magnetite

20. What is not ore Many volcanic ore formations have tons of pyrrohtite, marcasite, and pyrite. –Iron sulfides tend not to be ore because they require an extra process steps.

21. Processing Iron Ore Crushing and Grinding

22. Gravity Separation

23. Blast Furnace

24. Blast Furnace Operation Blast furnace diagram 1. Hot blast from Cowper stoves 2. Melting zone (bosh) 3. Reduction zone of ferrous oxide (barrel) 4. Reduction zone of ferric oxide (stack) 5. Pre-heating zone (throat) 6. Feed of ore, limestone, and coke 7. Exhaust gases 8. Column of ore, coke and limestone 9. Removal of slag 10. Tapping of molten pig iron 11. Collection of waste gasesHot blastCowper stovesferrous oxideferric oxideslagpig iron

25. Steel Converters

26. Casting Steel

27. What is Iron Used For

28. What are the Reserves and Production for Iron?

29. What is Iron Worth Around 8 to 10 cents a pound