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

PlanMining 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

Mining Ressources

in French Guiana

• 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

Mining situation

in French Guiana

Year 2004 Year 2008

Autorisations for exploitation-AEX 1km²

100 61

Autorisation for exploitation _ PEX (PME/PMI)-50km²

5 7

Concessions 27 28

Autorisations for exploration-PER 50km²

25 7

Total 156 103 they are not allon activity

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

Mining Permits

in French Guiana

AEX

PEX

concessions

PER

Consequences of mercury on health

and environnement

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Mercury in French Guiana

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-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.

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.

First way of alimentary exposure of methyl-mercure

Direct pollution : amalgam

Indirect pollution : erosion

Practises for the reduction of impacts

1-Mercury recovery by retorts

2-Mercury use prohibited (Jv 2006)

3- Alternatives mining practises

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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

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creuset

Sortie mercure

gaz

Retort : Mercury – Gold separation

Alternative mining techniques

-Shaking table : More or less fast and very expensive(>16 800$)

Alternative mining techniques

-Concentrators : Fast and good price (<8400$)

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Alternative mining practises

-Washing on the gravimetric table : Fast and not expensive

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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

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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

Second way of alimentary exposure of methyl-mercure : Indirect pollution : erosion

Indirect pollution : erosion

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

transports solides sur 20 ha

0

40

80

120

160

forêt surface terrassée Prairie

T/a

nErosion causes turbidity and re-circulation of historic and/or natural mercury

Impacts of deforestation and solutions with grass seeding

forest Meadow

Deserted surfaces

Water turbidity

French regulation’s level of turbidity :

35 mg/L = 250 NTU

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

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Forest

Wood stocks

Waste rockGravel’s cone

Bassins

Pumping

Saprolit

Close circuit

pond1

pond2

pond3

Pump of water in the first bassin

Mud discharge

Communication

chanel

Close circuit

Other way for the reduction of impacts

The reclamation

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…).

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.

Forest

Wood stocks

Waste rockGravel’s cone

Basins

Pumping

Saprolit

Just to remind the system…

Draining’s step – spreading of the gravel on river bed

Forest

Wood stocks

Drained basins

Gravel for the river bed

Saprolit

Waste rock

Forest

Wood stocks

Waste rock

Drained bassins

Gravel for the river bed

Saprolit

Preparation of the field _ filling in basins’s step

Drained basins

Preparation of the field _ restoring river step and spreading wood’s stocks’s step

Forest

Sreaded wood stock

Waste rock

Restored river

Gravel

Saprolit

Replantation and seeding’s step

Forest

Trees plantation’s bands

Waste rock

Restored river

Seeding’s bands

Saprolit

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

Last way for the

Reduction of impacts

The flocculation

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Polymer flocculation

flocculentpolymer

Chargeneutralization

+

+

+ ++

++

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.

“The bigger and heavier they are,the faster they fall…”

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

Before flocculation

After flocculation

Results

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

SMPA ‘s mine - piste Coralie - Roura

The Mine’s trees nursery (Pépinière Des Mines)- piste Coralie - Roura

Water shedlimit

Tomorow : Visites on the field

Localisation of the next visites

cayenne

Mining visite