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  • 1. Management of the natural ressources on the Guianas Gestion des ressources naturelles sur le plateau des Guyanes To Help move the industry towards less impacting mining practices Au Hg
  • 2.
    • Plan
    • Mining Ressources in French Guiana
    • Differents gold permits
    • Mining situation
    • Mining Permits
    • Consequences of mercury on health and environnement
    • Mercury in French Guiana
    • First way of alimentary exposure to the mercury: direct pollution with amalgam.
    • Practises for the reduction of impacts
        • Alternative mining practises : shaking table, concentrators etc.
    • Second way of alimentary exposure to mercury : Indirect pollution : erosion - Water turbidity
    • Practises for the reduction of impacts
    • -Close circuit for the process water
    • -Progressive reclamation and re-vegetation
    • -The flocculation
    Au Hg
  • 3. Mining Ressources in French Guiana
  • 4.
    • Prospection :
    • ARM  : Type of « permit » allowed only for prospection-4 months – max : 3*1km²
    • PER  : Permit of max 50 km², only for prospection-5 years. And once more.
    •     Exploitation  : NB : Dredge exploitation prohibited
    • 3 types of permits exist : Concession, PEX : Exclusive Exploitation Permit and AEX (authorized exploitation) wich are specifics to the French Guyana (DOM).
    • Concession : For 50 years long, possible renewal of 25 years, no limit for the surface, difficult to obtain.
    • PEX  : Exclusive Exploitation Permit, for 5 years renewal twice, 49 km² max.
    • AEX  : Authorized exploitation of 1 km², 4 years renewal once, with the first objective to promote the small scale mining.
    Differents gold permits in french Guiana
  • 5. Mining situation in French Guiana 61 permits are spreaded on the Ouanary/Grand Santi axe and Camopi/ Maripasoula axe. The reduction is due to the enforcement of the regulations and difficulties to find a new and no protected zone 103 they are not allon activity 156 Total 7 25 Autorisations for exploration-PER 50km² 28 27 Concessions 7 5 Autorisation for exploitation _ PEX (PME/PMI)-50km² 61 100 Autorisations for exploitation-AEX 1km² Year 2008 Year 2004
  • 6. Mining Permits in French Guiana AEX PEX concessions PER
  • 7. Consequences of mercury on health and environnement 17, 08, 19 Novembre 2008
  • 8. Mercury in French Guiana 17, 08, 19 Novembre 2008 -Mercury’s utilisation in gold activity is forbidden since 01/01/06 by prefectoral order (n°1232/SG du 08 juin 2004. ). - Recovered gold amalgamed by mercury should be sent to a conformed laboratory for separation. -The actual mines are mostly situated on the sites that were previously used. -The content of mercury in the soil of french Guyana is 8 times higher than in France (soil of the region temperred climate) -Natural erosion of the ground generates from gold mining activities will lead to a remobilization of this mercury. -Level OMS (mondial health ‘s organization) : 50 microgrammes mercury par kg de chair.
  • 9. 17, 08, 19 Novembre 2008 -This mercury will support phenomen of bioacumulation. -Many studies were made to deepen the mercury problems in french Guyana : about risk of contamination of population, impactson environnement / mercury discharged by the soil erosion / reexploitation of old gold-mines sites. -In 1994, a study by IVS (Institut de veille sanitaire) revealed the mercury contamination among the Amerindians of Wayana population, living in the further zones of french Guyana, especially in the aera of upper Maroni. -Recently accomplished study by CNRS and BRGM of «  sediments and fish’s regional mercury distribution in the sediments and fishs in waterways of french Guyana.
  • 10. First way of alimentary exposure of methyl-mercure Direct pollution : amalgam Indirect pollution : erosion
  • 11. Practises for the reduction of impacts 1-Mercury recovery by retorts 2-Mercury use prohibited (Jv 2006) 3- Alternatives mining practises 17, 08, 19 Novembre 2008
  • 12. Alternative mining practises -Shaking table : More or less fast and very expensive (>16 800$) -Concentrators : Fast and good price (<8400$) -Pan : Long but not expensive -Washing on the gravimetric table : Fast and not expensive 17, 08, 19 Novembre 2008
  • 13. creuset Sortie mercure gaz Retort : Mercury – Gold separation
  • 14. Alternative mining techniques -Shaking table : More or less fast and very expensive (>16 800$)
  • 15. Alternative mining techniques -Concentrators : Fast and good price (<8400$)
  • 16. 17, 08, 19 Novembre 2008 Alternative mining practises -Washing on the gravimetric table : Fast and not expensive
  • 17. 17, 08, 19 Novembre 2008 Gold in the carpet 1 : remove the metal grid 2 : Make a « surverse » limit 3 : remove the carpets Washing without mercury on the gravimetric table
  • 18. 17, 08, 19 Novembre 2008 4 : wash the carpets on the table 5 : recover sand and gold 6 : wash the sand and gold 7 : recover the clean gold Washing without mercury on the gravimetric table
  • 19. Second way of alimentary exposure of methyl-mercure : Indirect pollution : erosion Indirect pollution : erosion
  • 20. L’érosion des sols Les transports solides dans l’écosystème forestier tropical humide guyanais : effets du défrichement et de l’aménagement de pâturages . J.M. FRITSCH et J.M. SARRAILH Erosion causes turbidity and re-circulation of historic and/or natural mercury Impacts of deforestation and solutions with grass seeding forest Meadow Deserted surfaces
  • 21. Water turbidity French regulation’s level of turbidity : 35 mg/L = 250 NTU
  • 22. Practises for the reduction of impacts Keys environmental issues on alluvial mines -Close circuit for the process water -Progressive reclamation All of thos practices will reduce the mercury’s risk 17, 08, 19 Novembre 2008
  • 23. Forest Wood stocks Waste rock Gravel’s cone Bassins Pumping Saprolit Close circuit pond1 pond2 pond3
  • 24. Pump of water in the first bassin Mud discharge Communication chanel Close circuit
  • 25. Other way for the reduction of impacts The reclamation
  • 26.
    • Why is reclamation necessary?
    • To fix the ground
    • To avoid the erosion fields, restricting suspended solids in the water
    • To help forest coming back
    • To eradicate stagnant water
    • To limit mercury’s methylation
    • To limit mosquitoes’s development (malaria…).
  • 27. Reclamation and mining regulation in French Guiana
    • There is usually, no possibility to obtain a new permit without restoration of the last permit.
    • There is no obligation to replant but it’s very recommended
    • Now, reclamation must be step by step :
    • The mining operator must restore the last 500m before beginning an other part of the river.
  • 28. Forest Wood stocks Waste rock Gravel’s cone Basins Pumping Saprolit Just to remind the system…
  • 29. Draining’s step – spreading of the gravel on river bed Forest Wood stocks Drained basins Gravel for the river bed Saprolit Waste rock
  • 30. Forest Wood stocks Waste rock Drained bassins Gravel for the river bed Saprolit Preparation of the field _ filling in basins’s step Drained basins
  • 31. Preparation of the field _ restoring river step and spreading wood’s stocks’s step Forest Sreaded wood stock Waste rock Restored river Gravel Saprolit
  • 32. Replantation and seeding’s step Forest Trees plantation’s bands Waste rock Restored river Seeding’s bands Saprolit
  • 33.
    • Why replanting or sowing ?
    • Important in the very large mine out area
    • To speed up the healing
    • To regain organic soil – to favour local species needing shadow, with plantation of pioneer species.
    • To limit conveyance of Mercury between soil and atmosphere with a new plant’s cover.
    • Phyto-remediation : Mercury is fixed in different types of trees.
    Palm nursery
  • 34. Last way for the Reduction of impacts The flocculation 17, 08, 19 Novembre 2008
  • 35. Polymer flocculation flocculent polymer Charge neutralization + + + + + + + Negatives charges Mercury discharge into the environment is usually trapped in soft sediments of river and can be released through flash flooding and bottom fish fedding. That’s why flocculation is important.
  • 36. “ The bigger and heavier they are, the faster they fall…”
  • 37. Cuve de floculant Washing riddle Gravel’s cone High pressurewater minerai The ponds (basins) La Moquette Injection’s points Zoom on the flocculent’s injection Rapid moving water Moving water Gravity’s flow out How it works Flocculent’s tank
  • 38. Before flocculation After flocculation Results
  • 39. Conclusions Mercury has been prohibited in French Guiana on legal mines only. Differents practises have been presented and some of them are adapted to others countries. . But for, a less impacting mining we need more : We need to : -Developp an environmental management -Improve the monitoring capacity -Motivate miners for the initiatives of alternative mining practises Thancks all for your attention and initiatives FFEM – DGIS - WWF
  • 40. SMPA ‘s mine - piste Coralie - Roura The Mine’s trees nursery (Pépinière Des Mines)- piste Coralie - Roura Water shed limit Tomorow : Visites on the field
  • 41. Localisation of the next visites cayenne Mining visite