sousa veiga mercury use reduction in the tapajos region
TRANSCRIPT
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Mercury Use Reduction and Land Mercury Use Reduction and Land Reclamation in the Tapajos Region, BrazilReclamation in the Tapajos Region, Brazil
by Rodolfo N. Sousa/ Marcello Veiga by Rodolfo N. Sousa/ Marcello Veiga
CASM Conference - Brasilia Oct/2008
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Global Mercury ProjectGlobal Mercury Project
A United Nations (GEF/UNIDO) A United Nations (GEF/UNIDO) program created in 2002 aiming to:program created in 2002 aiming to:
Reduce Hg pollution caused by ASMReduce Hg pollution caused by ASM
Introduce and disseminate good Introduce and disseminate good practicespractices
Train miners and develop community Train miners and develop community awareness awareness
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TanzaniaTanzania
SudanSudan
ZimbabweZimbabwe
BrazilBrazil
IndonesiaIndonesiaLaosLaos
In collaboration with UBC Dept of Mining Engineering
Ecuador
Venezuela
Guinea
Ghana
Mozambique
CambodiaSuriname
Senegal
Colombia
Global Mercury ProjectGlobal Mercury Project
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The Amazon scenario
Area of 5,5 million kmArea of 5,5 million km22 in 9 countries, of which in 9 countries, of which 72% (4 million km72% (4 million km22) is located in Brazil) is located in Brazil
The Brazilian Amazon has lost 18% of its original The Brazilian Amazon has lost 18% of its original area or 650,000 kmarea or 650,000 km22 (larger than France) (larger than France)
The Amazon looses 0.27% - 0.65% of its area The Amazon looses 0.27% - 0.65% of its area every year or 24,000 kmevery year or 24,000 km22 (the size of Belgium) (the size of Belgium)
Deforestation in the Amazon started in 1970’sDeforestation in the Amazon started in 1970’s
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Deforestation in the AmazonDeforestation in the Amazon
4 million km2
Garimpo Canaan
Brasilia
18% deforestation
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1980’s: Serra Pelada, the largest 1980’s: Serra Pelada, the largest concentration of miners in the worldconcentration of miners in the world
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2008: Typical Mining communities 2008: Typical Mining communities (“garimpos”)(“garimpos”)
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Magnitude of ASM in the TapajósMagnitude of ASM in the Tapajós
40,000 miners40,000 miners
500 to 2,000 mining sites500 to 2,000 mining sites
400 air strips400 air strips
5.8 tonnes/year of gold 5.8 tonnes/year of gold
10-12 tonnes/year of Hg for amalgamation10-12 tonnes/year of Hg for amalgamation
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Socio-economic aspectsSocio-economic aspects
Most miners do not have mining permit or Most miners do not have mining permit or environmental license;environmental license;
Education is very limited;Education is very limited;
Gold is the main source of revenue;Gold is the main source of revenue;
A miner consumes 40g Hg/month, produces A miner consumes 40g Hg/month, produces 18g Au/month, and income of US$350/month18g Au/month, and income of US$350/month
Hg costs US$200/kg. Au is sold by US$25/g.Hg costs US$200/kg. Au is sold by US$25/g.
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Environmental and Health AspectsEnvironmental and Health Aspects
Mercury contamination: Mercury contamination: soil, air, biota, fish, soil, air, biota, fish, miners;miners;
High level of Hg in fish: High level of Hg in fish: 4 to 5ppm, cases of 4 to 5ppm, cases of 22ppm, whereas guideline is 0.5ppm;22ppm, whereas guideline is 0.5ppm;
Mercury vapor: Mercury vapor: amalgamation without retorts amalgamation without retorts and gold shops without proper filters;and gold shops without proper filters;
Water contamination: Water contamination: tailings disposed tailings disposed directly into the rivers (siltation exacerbates directly into the rivers (siltation exacerbates bioaccumulation), Hg, CN, oil, sewage, bioaccumulation), Hg, CN, oil, sewage, garbagegarbage
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Environmental and Health AspectsEnvironmental and Health Aspects
Drinking water: Drinking water: water consumed directly water consumed directly from local streams, no latrines or proper from local streams, no latrines or proper waste disposal, high level of malaria and waste disposal, high level of malaria and parasitosisparasitosis
Deforestation:Deforestation: pits are open in critical areas pits are open in critical areas along the streams and rivers. Very low level along the streams and rivers. Very low level of land reclamationof land reclamation
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Hydraulic monitors – huge open pits in the forestHydraulic monitors – huge open pits in the forest
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Sediment / tailings released directly into the riversSediment / tailings released directly into the rivers
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Sediments / tailings released directly into the riversSediments / tailings released directly into the rivers
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Sediment released by sluice boxes – Crepori RiverSediment released by sluice boxes – Crepori River
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Mobility of Hg-contaminated Tailings
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Tailings take >4 t/a of Hg to other areas
Hg is methylated and bioaccumalted downstream
Crepori River
200km
Tapajós River
Hg-rich Tailings from gold miners
Source: Telmer et al. (2006)
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ASM in the TapajosASM in the Tapajos
In 2006, Brazil produced 40 tonnes of gold, of In 2006, Brazil produced 40 tonnes of gold, of which 5.2 tonnes were produced by ASM which 5.2 tonnes were produced by ASM (estimated 3 tonnes in the Tapajos)(estimated 3 tonnes in the Tapajos)
300 – 600 pits, each with a volume greater than 300 – 600 pits, each with a volume greater than 10,000m10,000m33 are opened annually are opened annually
3 to 6,000,000 tonnes/a of tailings into the rivers 3 to 6,000,000 tonnes/a of tailings into the rivers
Area disturbed by excavation of pits by hydraulic Area disturbed by excavation of pits by hydraulic monitors in the Tapajos is around 12,000 hamonitors in the Tapajos is around 12,000 ha
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Scenario of Artisanal Mining an GMP’s approachScenario of Artisanal Mining an GMP’s approach
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Large number of people involvedLarge number of people involved Low level of formal education and basic infra structureLow level of formal education and basic infra structure Most miners are informal / ASM is a marginal activityMost miners are informal / ASM is a marginal activity ASM causes more environmental impact than most large ASM causes more environmental impact than most large
companies but they are not in the mediacompanies but they are not in the media Very low investment for ASM on the groundVery low investment for ASM on the ground
UNIDO / GMP acknowledge that:UNIDO / GMP acknowledge that: The project is a very important initiative, but very small in The project is a very important initiative, but very small in
scale when compared with the scale of the problem. scale when compared with the scale of the problem. Education and prevention are keywords for the success of Education and prevention are keywords for the success of
the projectthe project
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1. Training is a step to reach a result, but it is not a result in itself;
2. Number of trainees and program content are important information, but are not the result itself;
3. Training people does not imply that they have learned lessons;
4. Learning lessons does not imply that they will implement what they have learned;
But,
The real result of training occurs when the trainees incorporate the lessons learned to their daily routine
General statements about General statements about training programstraining programs
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Objectives & effectiveness evaluationObjectives & effectiveness evaluation
5 MAIN OBJECTIVES: 5 MAIN OBJECTIVES: Promote legalization of minesPromote legalization of mines Improvement of Gold ProductionImprovement of Gold ProductionProtection of Forest and WaterProtection of Forest and WaterReduction of Hg UseReduction of Hg Use Improve Health and SanitationImprove Health and Sanitation
Evaluation of “garimpos” Evaluation of “garimpos” prior to the prior to the training and 3 to 4 months after training and 3 to 4 months after trainingtraining
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Project promotion: “Take care of your treasure”Project promotion: “Take care of your treasure”
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Training of trainers (multipliers)
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Indoor TrainingIndoor Training
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Outdoor Training - Practical field lecturesOutdoor Training - Practical field lectures
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Multiplication of training / awareness campaignMultiplication of training / awareness campaign
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Multiplication of training / awareness campaignMultiplication of training / awareness campaign
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Evaluation before and after the trainingEvaluation before and after the training
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Introduction of biosand water filters
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Use of biosand filters for drinking water
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Accidents: landslides, fallings, motor pulley beltsAccidents: landslides, fallings, motor pulley belts
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Miner Burning Amalgam (exposed to Hg vapor)Miner Burning Amalgam (exposed to Hg vapor)
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Demonstration of homemade retorts
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Distribution of retorts to disseminate the culture of Distribution of retorts to disseminate the culture of protection against mercury vapour during the protection against mercury vapour during the
amalgam burningamalgam burning
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Kitchen bowl retort Kitchen bowl retort (homemade solution)(homemade solution) Hg condenses on
the glass bowl
Wet sand to seal Hg vapour
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3636Brasil, 2006Brasil, 2006
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60 retorts like this purchased locally60 retorts like this purchased locally
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Use of retorts to burn amalgam and recover HgUse of retorts to burn amalgam and recover Hg
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Demonstration of mercury reactivation and recyclingDemonstration of mercury reactivation and recycling
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Fume hoods: developed local supplier, Filters installed Fume hoods: developed local supplier, Filters installed in local gold shopsin local gold shops
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Fume hood in Gold Shops: GMP & USEPAFume hood in Gold Shops: GMP & USEPA
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TDU - Transportable Demonstration UnitTDU - Transportable Demonstration Unit
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Cyanidation tests – A lab in the jungleCyanidation tests – A lab in the jungle
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Homemade prototypes (Homemade prototypes (amalgamator)amalgamator)
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Pool for amalgamation of concentratePool for amalgamation of concentrate
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Construction of latrinesConstruction of latrines
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Garbage disposalGarbage disposal
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General structure of the Action PlanGeneral structure of the Action Plan
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Vision
Mission
General Objectives
Performance Indicators
Monitoring processes and results
Goals
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Most relevant indicators
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General Objectives
Performance Indicator
% mines attaining requisites
Evaluation before
training
Goals for after
training
Results after
training
Protection of water and forest
Refilling old pits with tailings 40.6 80.0 91.7
Reforestation of degraded areas 1.5 5.0 5.0
Quality of water / sediment containment 35.1 60.0 91.7Use of Mercury
Mercury reactivation and recycling 4.3 50.0 91.7
Mercury confinement ( amalgamation) 10.9 50.0 75.0
Use of retorts during burning process 20.3 40.0 41.2Health, Sanitation
and SafetyUse of latrines 26.8 50.0 91.7
Use of filtered drinking water 17.0 60.0 81.3
Use of methods for prevention of malaria 62.0 80.0 81.3
Garbage disposal 16.3 50.0 100.0
Practices of internal awareness of miners 0.7 10.0 10.2
Mean 21.4 48.6 69.2
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Reclamation in ASMReclamation in ASM
Complex and costly reclamation methods are not Complex and costly reclamation methods are not effective in ASM. effective in ASM.
Simplicity is mandatory. For example, soil Simplicity is mandatory. For example, soil salvation is an ideal technique but complex for salvation is an ideal technique but complex for ASMASM
Cases of rehabilitation are “volunteer initiatives”, Cases of rehabilitation are “volunteer initiatives”, as non-compliance is prevalentas non-compliance is prevalent
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Garimpo CanaanGarimpo Canaan
Garimpo Canaan is a typical ASM site in the Garimpo Canaan is a typical ASM site in the Tapajos with 10,000haTapajos with 10,000ha
Gold grade = 0.25 g/tGold grade = 0.25 g/t
The area is only accessible by boat or small The area is only accessible by boat or small airplanesairplanes
Process: hydraulic monitors, sluice boxes and Process: hydraulic monitors, sluice boxes and mercury amalgamationmercury amalgamation
Canaan employs around 20 people, involving Canaan employs around 20 people, involving miners, cook, general helpersminers, cook, general helpers
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Garimpo CanaanGarimpo Canaan
Reclamation StepsReclamation Steps
1.1. Relocation of sluice boxes to fill old open pitsRelocation of sluice boxes to fill old open pits
2.2. Triple barrier to retain sediments Triple barrier to retain sediments
3.3. Seedling productionSeedling production
4.4. Fertilization / silvicultural managementFertilization / silvicultural management
5.5. Harvest managementHarvest management
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Garimpo CanaanGarimpo Canaan
Objectives of the Objectives of the reclamation program: reclamation program:
Reduction of river siltation; Reduction of river siltation; Recomposing the landscape; Recomposing the landscape; Diversification of the economyDiversification of the economy
Amazonian Mahogany (Amazonian Mahogany (Swietenia macrophylla Swietenia macrophylla KingKing) reaches price of US$ 800/) reaches price of US$ 800/mm33
One hectare of One hectare of Mahogany Mahogany with 556 trees can with 556 trees can produce 100 mproduce 100 m3 3 in 25 years in 25 years
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Environmental Impact of planting Environmental Impact of planting MohoganyMohogany
Natural density of Mahogany in the Amazon Natural density of Mahogany in the Amazon forest ranges from 0.3 to 2.1 trees/ha forest ranges from 0.3 to 2.1 trees/ha
The plantation in Canaan produced 285 to 555 The plantation in Canaan produced 285 to 555 trees/ha, which is equivalent to the amount of trees/ha, which is equivalent to the amount of Mahogany found in 1,000 ha of natural forest Mahogany found in 1,000 ha of natural forest
For each Mahogany tree harvested in the natural For each Mahogany tree harvested in the natural environment, about 31 other trees with diameter environment, about 31 other trees with diameter above 10 cm are cut in order to obtain the above 10 cm are cut in order to obtain the MahoganyMahogany
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Sluice box removed from river / barrier to retain sedimentsSluice box removed from river / barrier to retain sediments
5555
Open Pit: 20,000 m3 earth to rivers Sluice box removed from river.
Triple barrier to retain sediments Old pit refilled. Clean water to river
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Refilling old pits: most critical step in rehabilitationRefilling old pits: most critical step in rehabilitation
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Reforested areas in CanaanReforested areas in CanaanArea denomination
1A 1B 1C 1D
Common name African Mahogany Neem Teak Amazon
Mahogany
Scientific name Khaya ivorensis
Azadirachta indica
Tectona grandis
S. macrophylla King
Area (m2) 16310 54215 17885 7578
# seedlings 466 1549 511 421
Date plantation Feb/03 Feb/03 Mar/04 Apr/02
Age (years) 5.8 5.8 4.7 6.6
Spacing (m) 7 x 5 7 x 5 7 x 5 6 x 3
# trees/ha 285 285 285 556
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Reforested areas in CanaanReforested areas in Canaan
Block Species Diameter Height Basal area Volume Survival
Rate
Common
name (cm) (m) B/ha m3/ha (%)
1A African Mahogany 15.16 9.59 4.61 23.19 81.05
1B Neem 14.43 7.40 6.73 25.61 90.00
1C Teak 10.94 7.68 2.79 11.29 97.91
1D Amazon. Mahogany 13.72 8.05 7.57 31.66 84.91
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Summary / lessons / Conclusions
141 locations, 4200 miners trained, 91.7% sluices removed from river after training (2nd evaluation)
300-600 open pits / year
6,000,000 tonnes of tailings
Garimpo Canaan was promoted as role model site
Refilling pits is the most important step in reclamation
If at least refilling is done, nature will provide coverage
Reforestation: Volume 100m3/ 25 years, >80 survival
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Summary / lessons / Conclusions
SIMPLICITY is a key factor for the success of program in ASM (scale of ASM, remoteness, lack of infra structure and low level of formal education)
PREVENTION of environmental & health impact is cheaper, more rational and feasible than any corrective method
EDUCATION and AWARENESS are key factors for prevention and requires continuous training and campaigns.
EFFECTIVENESS must be evaluated and PERFORMANCE INDICATORS are appropriate tools
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Summary / lessons / Conclusions
20 “good practices” were promoted and 8 showed substantial impact: reactivation and recycling of mercury, pool for amalgamation, old pits refilling, sediment containment, garbage disposal, use of retorts, use of latrines, filtered water.
Practices related to promotion of legalization and gold production require more time for consolidation.
Local suppliers were prepared to develop retorts, fume hoods, filters and ball mill
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Summary / lessons / Conclusions
Impact on Hg reduction was 1,752kg (4,200 miners trained, Hg reactivation: 4.3% to 91.7%)
Potential to remove 16,780kg of Hg by extending the training for the whole population (40,000)
Improvement of grades (21.4 to 69.2%) is the best evidence that miners respond to education better than stringent legislation only.
Improvement of grades expresses changes in behaviour Mission Accomplished
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