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Welcome

Welcome. IAMGOLD ROSEBEL GOLDMINES SURINAME REGIONAL EXPLORATION. STRUCTURE OF PRESENTATION. Introduction Geology and property geology Weathering profile Goldmobilization and mushroom effect Exploration. INTRODUCTION. Regional Exploration Find new targets for the mine

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Welcome

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  1. Welcome IAMGOLD ROSEBEL GOLDMINES SURINAME REGIONAL EXPLORATION

  2. STRUCTURE OF PRESENTATION • Introduction • Geology and property geology • Weathering profile • Goldmobilization and mushroom effect • Exploration

  3. INTRODUCTION • Regional Exploration • Find new targets for the mine • Active in and out of the mine-site • Working areas • Mine-site; J-zone, Spin-zone, Blauwe Tent etc • Koemboekreek en Kraboedoin • Sarakreek

  4. PROPERTY GEOLOGY

  5. GEOLOGY • The Rosebel concession lies within the Lower Proterozoic Guiana Shield, which stretches from the Amazon River in Brazil to the Orinoco River in Venezuela. • The Suriname portion of the shield consists of distinct belts of low-grade metamorphic rocks, separated by large areas underlain by granites and gneisses.

  6. LOWER PROTEROZOIC GEOLOGICAL UNITS OF SURINAME

  7. MAROWIJNE GROUP • Paramaka Formation (Basic to intermediate volcanic) • Armina Formation (deepmarine sediments and volcanics) • Rosebel Formation (Shallow marine-continental sediments)

  8. WEATHERING • Chemical weathering • Mechanical weathering

  9. TYPICAL WEATHERING PROFILE(TROPICS)

  10. TRANSITIONAL ZONE • Grading from slightly weathered rock through to saprolite • Primary minerals are pseudomorphically replaced by weathering products (such as kaolinite)

  11. SAPROLITE • Most weatherable primary minerals have been altered to secondary minerals such as kaolinite, goethite or amorphous iron oxyhydroxides. • Weathering is isovolumetric • The original rock fabric is preserved

  12. MOTTLED ZONE • Hydrated, clay-rich horizon • Contains vertical stripes and mottles of hydrated iron oxides • Water percolation creates a series of voids and channels, which can become filled with secondary kaolinite. • All original rock fabric is destroyed.

  13. MASSIVE CLAYZONE • Featureless • Brick red clay • Containing less than 10 percent iron oxide concretions and pisolites

  14. PISOLITIC CLAYZONE • Featureless • Brick red clay • Containing 10 to 95 percent iron oxide concretions and pisolites • Continued pisolite growth and cementation will eventually lead to development of duricrust

  15. GOLD MOBILIZATION • A leaching process takes place • Light material (such as clays) leach • Heavy material (such as gold) gets concentrated on the top layers • Which will eventually result in…

  16. MUSHROOM EFFECT

  17. EXPLORATION • To show indications, cheap and fast resulting methods are used • To define the ore-body more effective and structured methods are used

  18. EXPLORATION METHODS • Panning • Mapping of porknocking pits • BLEG sampling • Augering • Fieldmapping • Trenching • Diamond drilling

  19. PANNING

  20. MAPPING OF PORKNOCKING-PITS • Porknocking-pits indicate areas containing/contained gold • Using a GPS the boundaries can be mapped • While mapping the area, the source of gold can be determined (primary gold or alluvial gold)

  21. BLEG SAMPLING • BLEG = Bulk Leach Extractable Gold • After panning the concentrate of heavy minerals is sent to the lab • Gold is dissolved by cyanide and concentrated by extraction into an organic solvent.

  22. AUGERING • An auger is a device for moving material by means of a rotating helical flighting. • A drill bit uses this mechanism to remove shavings from a hole being drilled.

  23. AUGER-SAMPLING • At first • A large grid is augered with 400 meter spacing • At each station (with 25 meter spacing) samples are taken from the first 2 meters • When anomaly results are received • Around this anomaly a smaller grid is sampled • Sampling takes place each meter until 5 meter (deepauger)

  24. AUGER-PROCEDURE Samples are taken from each meter Therefore each each meter is: Logged (using the augerlogsheet) Sampled ID-ed

  25. AUGER-LOGSHEET

  26. SAMPLING • Each meter • At the end of meter • Homogenized • Quartered • 250 grams sample taken to sent for lab • And a small amount in a chiptray for reference and further analysis

  27. TRENCHING • A trench is a type of excavation in the ground • After studying assay results orientation and location of trench is determined

  28. WHY TRENCHING? • Create outcrops • Study controls of gold-mineralization and gold-mobilization • Determine if future drilling is needed • Study orientations of bedding and quartzveins • Determine how and at which orientation the possible drilling has to be done

  29. DIAMOND DRILLING • Diamond drilling is very expensive • Advantage is that you will get in situ material in fresh rock • After analyzing auger data and field-mapping data a drill spot is determined in the field

  30. The samples from augering, diamond drilling etc… are afterwards sent to the lab for analyzing • RGM Lab (on site) • The Assay Lab (Paramaribo) • Omai lab (Guyana)

  31. DOES ANYONE HAVE QUESTIONS?!

  32. THANK YOU… FOR YOUR ATTENTION

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