MERCURY POLLUTION ABATEMENT PROJECT MENART GEOVENTURES ENT LTD

MERCURY POLLUTION ABATEMENT PROJECT MENART GEOVENTURES ENT. LTD P. O. BOX 237 TARKWA GHANA PRESENTATION AT BRUSSELS BY PROF. S. AL-HASSAN 13 TH - 15 TH DECEMBER, 2010 1

OUTLINE OF PRESENTATION • Objective • ASSM Mining methods in Ghana • Available alternatives • Direct smelting – the technique • Laboratory and field trials • Challenges • Conclusions

OBJECTIVE • Identify and introduce techniques or processes to eliminate the use of mercury by artisanal and small-scale gold miners (ASM) in Ghana

MAP OF AFRICA SHOWING LOCATION OF GHANA • Area is about 230 020 km 2 • Population is about 21 million • Climate is tropical

GEOLOGICAL MAP OF GHANA SHOWING ROCK FORMATIONS THAT CONTAIN GOLD

LOCATION OF SMALL-SCALE MINNG DISTRICT CENTRES, GHANA District Location Centres Tarkwa, Bibiani, & Asankragua Region Western Assin Fosu, & Dunkwa- Central on-Offin Akim Oda Eastern Bolgatanga Upper East

ASSM GOLD & DIAMOND PRODUCTION Total Ghana Production Year Gold Prodn (oz) Diamond Prodn (carats) 2000 2, 457, 152 878, 011 2001 2, 381, 345 1, 090, 072 2002 2, 236, 833 963, 493 2003 2, 274, 627 904, 089 2004 2, 031, 971 905, 344 2005 2, 138, 944 1, 065, 923 2006 2, 342, 722 972, 991 2007 2, 628, 290 839, 235 Source: Minerals Commission, Ghana 1989 Gold 2% Diamonds 40% 2001 Gold 6% Diamonds 95% 2007 Gold 12% Diamonds 98%

ASSM MINING METHODS IN GHANA • • • Washing and Panning (alluvials along rivers) Dredging Shallow pitting (near surface placers) Underground mining (reefs) Tailings and waste dumps (of old closed mines)

MINING IN DRY AREA (ELUVIAL) 90% grain size greater than 1 mm

CONCENTRATION (DRY AREA) Winnowing Washing

MINING OF ALLUVIAL DEPOSITS

MINING HARD ROCK (REEFS)

SSM DREDGING IN GHANA (SUCTION)

MILLING (HARD ROCK)

FLOW SHEET FOR AMALGAMATION OPERATIONS Ore (hard rock) crushing/grinding gravity concentration mercury amalgamation filtration of excess mercury liquid mercury burning of amalgam mercury vapour sponge gold smelting bullion

SLUICING

PANNING

GOLD CONCENTRATE IN A PAN

AMALGAMATION

SQUEEZING EXCESS MERCURY FROM AMALGAM

FIREPLACE FOR BURNING AMALGAM

SPONGE GOLD

GATHER AND SELL

OPEN HEATTH FOR SMELTING GOLD

MERCURY LOSS • Spillage during amalgamation • Poor amalgam distillation • Disposal of amalgamation tailings • Further processing of sponge gold • it is estimated that for every gram of gold recovered at least 0. 43 g of mercury escapes

ALTERNATIVE PROCESSES TO AMALGAMATION • Physical methods Shaking tables , special sluices, Centrifugal concentrators. • Chemical methods Coal gold agglomeration IGoli Haber process Cyanide leaching Direct Smelting

SLUICING Method Equipment/ Principle Applicability Process Physical Sluice Gravity Used in virtually all small scale mining concentratio centres as a conventional rougher n leading to concentration unit. production of a rough concentrate that has to be cleaned further

COAL-GOLD AGGLOMERATION Method Equipment/ Principle Applicability Process Physico- Coal-Gold Agglomeration The process has been tested in Australia, South chemical Agglomeration of the gold Africa, Brazil and Tanzania. It appears that particles and despite its apparent attractions, it was never coal, followed actually put in to operation and more research is by with flotation required. diesel, kerosene and other oils. The float concentrate has to be processed and smelted

Igoli Process Method Equipment/ Principle Applicability Process Chemical IGoli process Leaching with The process has been applied in South Africa HCl and Tanzania. Due to the safety hazards Na. OCl involved in working with acids and the miners followed by lack of training in chemistry. Mintek insists on filtration and miners attending a training course. It is precipitation currently more suited to organised medium with sodium scale rather than artisanal and small scale metabisulphite. mining operations. The slimes precipitated are calcined and smelted

CYNIDATION Method Equipment/ Principle Applicability Process Chemical Cyanidation Leaching with Cyanidation has been applied by small scale sodium Cyanide miners in Colombia, Bolivia, Brazil and oxygen Zimbabwe. The method is not fast enough for followed by processing concentrates. It is poisonous and illegal adsorption onto in some countries like Ghana activated carbon, elution, electrowinning and smelting. Concentrated solution that requires further processing

HABER PROCESS Method Equipment/ Principle Applicability Process Haber Leaching with The leaching reagent is proprietary. For this process a artisanal miners have to take their ore to processing concentrated centres where it is processed. This is not applicable to solution that the artisanal mining environment as: requires too costly and too complex for individuals or small further groups processing uses a proprietary chemical thus locking the miners into a foreign third party supplier has major issues of trust and keeping track of an individual’s ore

DIRECT SMELTING Method Equipment/ Principle Applicability Process Chemical Direct Smelting Melting black Smelting is applied in most small scale centres sand miners are familiar with the method as it is concentrates to being used for purifying sponge gold. It has been produce pure developed, tested and commercialised in Ghana. gold It can be used for all types of ores and comparatively cheaper than amalgamation.

CRITERIA OF SUITATBLE ALTERNATIVE FOR GALAMSEYERS • Effective • Easy - requires no special equipment • Quick • Cheap • Suitable for processing small batches of concentrate • Visible - the miners can see their products throughout the whole process • Locally available

CHOICE OF DIRECT SMELTING • Fulfils all main criteria • Uses non-toxic, cheap chemicals: borax, sodium carbonate, silica sand

SMELTING • Smelting is a high-temperature melting process used to recover metals from ores and concentrates • Fluxes are added to the concentrate to assist melting and react with impurities so that the metal separates out • The final products are pure metal and a glassy slag containing the unwanted components

SMELTING VS AMALGAMATION • Smelting gave 99. 9% recovery • In the lab amalgamation gave around 97% recovery • In the field amalgamation gave around 88% recovery

MIXING CHARGE AND FEEDING CRUCIBLE

ALTERNATIVE FUELS LPG 38

FURNACES 39

GAS FURNACE 40

GAS FURNACE 41

DIMENSIONS OF GAS FURNACES DIMENSIONS ITEM Small Size (1) Large Size (4) Height 280 mm External Diameter 240 mm 405 mm Internal diameter 170 mm 375 mm Thickness of insulation 30 mm 60 mm Thickness of metal shell 50 mm Length of LPG inlet pipe 190 mm Air slot length 95 mm Air slot width 10 mm Number of air slots 3 3 42

GAS FURNACE 43

INLET PIPE SUB-ASSEMBLY 44

TOP COVER SUB-ASSEMBLY 45

CASING SUB-ASSEMBLY 46

CHUTE SUB-ASSEMBLY 47

COST ELEMENTS OF LARGE SIZE GAS FURNACE SN Item Quantity Unit Cost (GH¢) Total Cost (GH¢) 1 Casing 1 290. 00 2 Lining 1 120. 00 3 Ring 1 5. 00 4 Clips 2 0. 10 0. 20 5 Hose (4 m) 1 6. 00 6 Valve 1 3. 00 7 Regulator 1 20. 00 8 Hood 1 30. 00 9 Miscellaneous 5. 80 Total 480. 00 48

COST ELEMENTS OF SMALL SIZE GAS FURNACE SN Item Quantity Unit Cost (GH¢) Total Cost (GH¢) 1 Casing 1 220. 00 2 Lining 1 90. 00 3 Ring 1 5. 00 4 Clips 2 0. 10 0. 20 5 Hose (4 m) 1 6. 00 6 Valve 1 3. 00 7 Regulator 1 20. 00 8 Hood 1 30. 00 9 Miscellaneous 5. 80 Total 380. 00 49

COST OF KIT WITH LARGE SIZE GAS FURNACE SN Item Quantity Unit Cost (GH¢) Total Cost (GH¢) 1 Gas furnace (L/S) 1 480. 00 2 Gas cylinder (15 kg) 1 70. 00 3 Gas (15 kg) 1 12. 00 4 Fire extinguisher (4 kg) 1 50. 00 5 Tongs 2 7. 00 14. 00 6 Cupels 2 15. 00 30. 00 7 Hammer 1 3. 00 8 Gloves 2 2. 00 4. 00 9 Goggles 1 4. 00 10 Spoons 2 0. 20 0. 40 11 Weighing scale 1 80. 00 12 Crucibles 100 0. 40 40. 00 13 Flux reagents 1 200. 00 14 Mixing bowl 2 2. 00 4. 00 Total 991. 40 50

COST OF KIT WITH SMALL SIZE GAS FURNACE SN Item Quantity Unit Cost (GH¢) Total Cost (GH¢) 1 Gas furnace (S/S) 1 380. 00 2 Gas cylinder (15 kg) 1 70. 00 3 Gas (15 kg) 1 12. 00 4 Fire extinguisher (4 kg) 1 50. 00 5 Tongs 2 7. 00 14. 00 6 Cupels 2 15. 00 30. 00 7 Hammer 1 3. 00 8 Gloves 2 2. 00 4. 00 9 Goggles 1 4. 00 10 Spoons 2 0. 20 0. 40 11 Weighing scale 1 80. 00 12 Crucibles 100 0. 40 40. 00 13 Flux reagents 1 200. 00 14 Mixing bowl 2 2. 00 4. 00 Total 891. 40 51

DEMONSTRATION AND TRAINING 52

DEMONSTRATION IN THE FIELD 53

POURING OF MOLTEN MATERIAL

COOLING OF MELT IN A MOULD

SEPARATION OF GOLD FROM SLAG 56

SEPARATION OF GOLD FROM SLAG Gold

GOLD BEAD

COST COMPARISON AMALGAMATION SN Item Cost (GH¢) DIRECT SMELTING SN Item Cost (GH¢) 1 Half teaspoon of mercury (27 g) 4. 00 1 4 Crucibles (2 operations) 2 Heating of amalgam 0. 50 (charcoal) 2 Flux (2 x 200 g) 1. 20 3 Smelting 1. 50 3 Gas (2 x 0. 75 g) 1. 20 Total 6. 00 (US$4. 14) Total 1. 60 4. 00 (US$2. 76)

COST ESTIMATES for GAS KIT SN Item Quantity Unit Cost (GH¢) Total Cost (GH¢) 1 Gas furnace (S/S) 1 500. 00 2 Gas cylinder (15 kg) 1 70. 00 3 Gas (15 kg) 1 15. 00 12. 00 4 Fire extinguisher (4 kg) 1 55. 00 5 Tongs 2 7. 00 14. 00 6 Cupels 2 80. 00 160. 00 7 Hammer 1 3. 00 8 Gloves 2 2. 00 4. 00 9 Goggles 1 4. 00 10 Spoons 2 0. 20 0. 40 11 Weighing scale 1 100. 00 12 Crucibles 100 0. 40 40. 00 13 Flux reagents 1 200. 00 14 Mixing bowl 2 2. 00 4. 00 1166. 40* (US$804. 41) Total

CHALLENGES 1. Retrieval of loan balances 2. How is the money accruing from the sale of the kits to be used? 3. Formation and sustenance of Small Scale Miners’ Associations 4. Sustenance of the Mercury Abatement Programme (accessibility & affordability) 5. Further follow-up to sustain the momentum of the use of the technology. 61

THE WAY FORWARD - GHANA 1. Ensure that the kits are readily available and accessible virtually at the door steps of the ssm; 2. Monies accruing from the sale of the kits should serve as revolving fund; 3. Outstanding loan balances should be retrieved by the respective District Offices of the MC; 62

THE WAY FORWARD - GHANA CONT’D 4. Encourage the formation and strengthening of the SSM Associations 5. Monitoring and follow-up should be continued for at least two (2) years; 6. Use of the direct smelting method should be made a condition for the acquisition of license where amalgamation is used 63

THE WAY FORWARD - GLOBAL To achieve this feat it is recommended that the: 1. ACP country should provide a budget or secure donor funds to launch the project possibly using the Ghana Project as model (at least € 200, 000. 00); 2. ACP country should organise a Management Unit (Ministry of Mines, University, NGOs, etc) to manage the project; 3. ACP country should recruit local consultants with experience in artisanal and small scale mining of gold to undertake the project

THE WAY FORWARD – GLOBAL CONT’D 4. Menart Geoventures Ltd, University of Mines and Technology, Tarkwa – Ghana, could be contracted to provide fabrication plans and a complete kit; 5. Menart Geoventures Ltd, University of Mines and Technology, Tarkwa Ghana may be contacted to provide high level consultants to supervise the project.

ACKNOWLEDGEMENT • MINISTRY OF FINANCE & ECONOMIC PLANNING, GHANA • EUROPEAN UNION • MINERALS COMMISSION, GHANA • PROJECT MANAGEMENT UNIT, GHANA • BRITISH GEOLOGICAL SURVEY • UNIVERSITY OF MINES & TECHNOLOGY, TARKWA (UMa. T), GHANA • ACP GROUP 66

RIDE A CROCODILE AT PAGA, GHANA