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

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

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

4. MAP OF AFRICA SHOWING LOCATION OF GHANA
Area is about km2
Population is about 21 million
Climate is tropical

5. GEOLOGICAL MAP OF GHANA SHOWING ROCK FORMATIONS THAT CONTAIN GOLD

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

7. 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
SSM
Contribution
1989
Gold 2%
Diamonds 40%
2001
Gold 6%
Diamonds 95%
2007
Gold 12%
Diamonds 98%
Source: Minerals Commission, Ghana

8. 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)

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

10. CONCENTRATION (DRY AREA)
Washing
Winnowing

11. MINING OF ALLUVIAL DEPOSITS

12. MINING HARD ROCK (REEFS)

13. SSM DREDGING IN GHANA (SUCTION)

14. MILLING (HARD ROCK)

15. 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

16. SLUICING

17. PANNING

18. GOLD CONCENTRATE IN A PAN

19. AMALGAMATION

20. SQUEEZING EXCESS MERCURY FROM AMALGAM

21. FIREPLACE FOR BURNING AMALGAM

22. SPONGE GOLD

23. GATHER AND SELL

24. OPEN HEATTH FOR SMELTING GOLD

25. 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 0.43g of mercury escapes

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

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

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

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

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

31. HABER PROCESS Method Equipment/ Process Principle Applicability Haber
Leaching with a concentrated solution that requires further processing
The leaching reagent is proprietary. For this process artisanal miners have to take their ore to processing centres where it is processed. This is not applicable to the artisanal mining environment as:
too costly and too complex for individuals or small groups
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

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

33. 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

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

35. 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

36. SMELTING VS AMALGAMATION
Smelting gave 99.9% recovery
In the lab amalgamation gave around 97% recovery
In the field amalgamation gave around 88% recovery

37. MIXING CHARGE AND FEEDING CRUCIBLE

38. ALTERNATIVE FUELS LPG 38 38

39. FURNACES 39 39

40. GAS FURNACE 40 40

41. GAS FURNACE 41 41

42. DIMENSIONS OF GAS FURNACES
ITEM
DIMENSIONS
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 m
50 mm
Length of LPG inlet pipe
190 mm
Air slot length
95 mm
Air slot width
10 mm
Number of air slots 3 42 42

43. GAS FURNACE 43 43

44. INLET PIPE SUB-ASSEMBLY44 44

45. TOP COVER SUB-ASSEMBLY45 45

46. CASING SUB-ASSEMBLY 46 46

47. CHUTE SUB-ASSEMBLY 47 47

48. COST ELEMENTS OF LARGE SIZE GAS FURNACESN
Item
Quantity
Unit Cost (GH¢)
Total Cost (GH¢) 1
Casing
290.00 2
Lining
120.00 3
Ring
5.00 4
Clips
0.10
0.20 5
Hose (4 m)
6.00 6
Valve
3.00 7
Regulator
20.00 8
Hood
30.00 9
Miscellaneous
5.80
Total
480.00 48 48

49. COST ELEMENTS OF SMALL SIZE GAS FURNACESN
Item
Quantity
Unit Cost (GH¢)
Total Cost (GH¢) 1
Casing
220.00 2
Lining
90.00 3
Ring
5.00 4
Clips
0.10
0.20 5
Hose (4 m)
6.00 6
Valve
3.00 7
Regulator
20.00 8
Hood
30.00 9
Miscellaneous
5.80
Total
380.00 49 49

50. COST OF KIT WITH LARGE SIZE GAS FURNACESN
Item
Quantity
Unit Cost (GH¢)
Total Cost (GH¢) 1
Gas furnace (L/S)
480.00 2
Gas cylinder (15 kg)
70.00 3
Gas (15 kg)
12.00 4
Fire extinguisher (4 kg)
50.00 5
Tongs
7.00
14.00 6
Cupels
15.00
30.00 7
Hammer
3.00 8
Gloves
2.00
4.00 9
Goggles 10
Spoons
0.20
0.40 11
Weighing scale
80.00 12
Crucibles
100
40.00 13
Flux reagents
200.00 14
Mixing bowl
Total
991.40 50 50

51. COST OF KIT WITH SMALL SIZE GAS FURNACESN
Item
Quantity
Unit Cost (GH¢)
Total Cost (GH¢) 1
Gas furnace (S/S)
380.00 2
Gas cylinder (15 kg)
70.00 3
Gas (15 kg)
12.00 4
Fire extinguisher (4 kg)
50.00 5
Tongs
7.00
14.00 6
Cupels
15.00
30.00 7
Hammer
3.00 8
Gloves
2.00
4.00 9
Goggles 10
Spoons
0.20
0.40 11
Weighing scale
80.00 12
Crucibles
100
40.00 13
Flux reagents
200.00 14
Mixing bowl
Total
891.40 51 51

52. DEMONSTRATION AND TRAINING52 52

53. DEMONSTRATION IN THE FIELD53 53

54. POURING OF MOLTEN MATERIAL

55. COOLING OF MELT IN A MOULD

56. SEPARATION OF GOLD FROM SLAG56 56

57. SEPARATION OF GOLD FROM SLAG

58. GOLD BEAD

59. COST COMPARISON AMALGAMATION DIRECT SMELTING SN Item Cost (GH¢) 1
Half teaspoon of mercury (27 g)
4.00
4 Crucibles (2 operations)
1.60 2
Heating of amalgam (charcoal)
0.50
Flux (2 x 200 g)
1.20 3
Smelting
1.50
Gas (2 x 0.75 g)
Total
6.00 (US$4.14)
4.00 (US$2.76)

60. COST ESTIMATES for GAS KITSN
Item
Quantity
Unit Cost (GH¢)
Total Cost (GH¢) 1
Gas furnace (S/S)
500.00 2
Gas cylinder (15 kg)
70.00 3
Gas (15 kg)
15.00
12.00 4
Fire extinguisher (4 kg)
55.00 5
Tongs
7.00
14.00 6
Cupels
80.00
160.00 7
Hammer
3.00 8
Gloves
2.00
4.00 9
Goggles 10
Spoons
0.20
0.40 11
Weighing scale
100.00 12
Crucibles
100
40.00 13
Flux reagents
200.00 14
Mixing bowl
Total
* (US$804.41)

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

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

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

64. THE WAY FORWARD - GLOBAL
To achieve this feat it is recommended that the:
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);
ACP country should organise a Management Unit (Ministry of Mines, University, NGOs, etc) to manage the project;
ACP country should recruit local consultants with experience in artisanal and small scale mining of gold to undertake the project

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

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

67. RIDE A CROCODILE AT PAGA, GHANA
THANK YOU