Luanshya Akatiti Dam

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LUANSHYA, AKATITI DAM TAILINGS LEACH PROJECT

INTRODUCTION:

Akatiti dam was the second tailings dam in Luanshya to be built. It was constructed when:

The feed grade of the ore from the mine was very high, and

The processing in the plant was not efficient.Because of these two factors, the grade of copper in the dam is extremely high, equivalent to ore

grade in many countries. Because of the age of the copper minerals in the dam, they are heavily

oxidised, and amenable to leaching and solvent extraction. It is recommended that 12 auger

samples be taken diagonally from the four corners of the dam to:

Establish the grade of the copper, and the acid soluble content of the tailings.

The thickness of the tailings, for tonnage estimation purposes. and

Establish the price to pay ZCCM-IH for the dam. They will want to charge based on total

copper content, the investor will only pay for recoverable copper acid soluble copper,

content.The financial plan was based on memory, as the author was in charge of rehabilitating this dam

from 1989 to 1992. The financial model, attached, shows a very lucrative. Using conservative

figures, a profit of $10-$12m per year is anticipated. A capital expenditure of $10m is required.

Treatment rate is estimated at about 4,500 tonnes per day. The infrastructure in the area is

excellent with roads and housing nearby. There are two independent power lines bordering the

property, to the East and South. The Chonga dam is less than 5 kilometres away, this dam will be

used to take the tailings effluent.

PROCESSING:

It is proposed to slurry the tailings using hydraulic monitors and pump the tailings to

Leaching tanks. Leaching will be carried out using sulphuric acid, most of which will be generated

from within the system. Leached tailings will be thickened and washed by counter current

decantation before discarding of the residue in Chonga dam. Pregnant leach solution (PLS) will be

fed to extraction mixer-settlers where the copper laden PLS will be contacted with solvent

extraction reagents to make a loaded organic (Figures 1 and 2).

Figure 1: Diagrammatic representation of the solvent extraction process


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Figure 2: Solvent

extraction reagent

The loaded organic will then be fed to the strip-mixer settler in which the copper will be extractedwith spent electrolyte coming from the electrowinning section to make a strong electrolyte

(Figure 3).

Figure 3: Block diagram showing the solvent extraction process

The raffinate generated is used to leach new copper. This might need topping up with fresh acid;

the amount of acid needed is controlled by the gangue acid consumption of the tailings. In this

case, it is not expected to exceed 40gt-1. That strong electrolyte (advance electrolyte) will be fed

to the electrolytic tankhouse where a DC current will be used to plate to copper onto stainless

steel cathodes (Figure 4 and 5).

Figure 4: DC rectiformer


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The whole process from leaching to harvesting plated copper is expected to take 28 days.

Figure 5: Electrolytic tankhouse showing busbar, anodes and cathodes

There is a plethora of such processing skill within Zambia, as at least four plants are using this

technology within the country.

Luanshya is one of the more attractive towns in Zambia and many workers will cherish the

opportunity to live and work there.

The property will be located only 25 kms from Ndola, the export hub.

The limited access to the property will enhance security.

Figure 6: Harvested

copper cathodes, ready

for sale


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Sulphuric acid will constitute a major cost component; since it is made as a by-product from

copper smelting, astute negotiations can secure it at a bargain price. The feasibility study was

done using world market price.

CAPITAL BUDGET:

Leaching/Solvent Extraction $800,000

Electrowinning $1,200,000

Purchasing the Dam $6,000,000

Environmental licence $100,000

Construction $500,000

Chemicals $850,000

Ponds construction and lining $475,000

Acid $115,000

Contingency $150,000

TOTAL $10,190,000

OPERATING COST:

Assuming a 15-year life of the

project

TNS TAILS23,595,000

AS Cu GRADE 0.45

TNS Cu CONTAINED 106,178

PLANT RECOVERY 60

TNS COPPER

RECOVERED63,707

COPPER PRICE ($/t) 6,500

OPS COST ($/t) 3,694

SALES $414,092,250

EXPENSE $235,360,125PROFIT $178,732,125

Profit per year $11,915,475

Payback period (years) 0.9


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ORGANISATION STRUCTURE:

The proposed organisation structure is shown below.

RECOMMENDATIONS:

It is recommended that the following be carried out:

A full reconnaissance of the area is conducted to establish the possible location of

the processing plant in relation to the power supply. The service of a person

knowledgeable in the area and with the tailings dam should be sought

12 auger samples be taken across the dam to accurately assess the leachable

copper content and the thickness of the deposit (Figure 7)

Figure 7: Proposed sampling

General Manager 1

Metallurgical Manager 1

Receptionist (1) 1

HR Superintendent Process Superintendent Maintanance Superintendent 3

General Foreman Sectional Engineer 2

Maintenance Foreman Electrical Foreman Instrumentation Foreman Boilermaker Foreman 4

Shift Foreman A Shift Foreman Swing Shift Foreman B 3

Accountant Storekeeper Security Officer Payroll Clerk Fitter Artisans (6) Electricians (2) Instrument Artisans (2) Boilermakers (2) 16

Reclaim (4) Reclaim (4) Reclaim (4) 12

Clerk (1) Issuer (1) Guards (4) Clerk (1) Leaching (1) Leaching (1) Leaching (1) Helper (1) Helper (1) Helper (1) Helper (1) 14

Solvent Extraction (2) Solvent Extraction (2) Solvent Extraction (2) 6

Driver (1) Ponds/Utilities (2) Ponds/Utilities (2) Ponds/Utilities (2) Driver (1) 8

CCD/Tailings (3) CCD/Tailings (3) CCD/Tailings (3) 9

Electrowinning (1) Electrowinning (1) Electrowinning (1) 3

Tails Dam (2) Tails Dam (2) Tails Dam (2) 6

Reagents Mixing (2) Reagents Mixing (2) Reagents Mixing (2) 6

Forklift Driver (1) Forklift Driver (1) Forklift Driver (1) 3

Driver (1) Driver (1) Driver (1) 3

TOTAL 101

Old Dam

N

Reliable

PowerSample Line

Points

AKATITI DAM

Less Reliable Power Line

To Masaiti

Lake Success

Proposed

Plant


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The dam be accurately measured to establish its area

A suitable local contractor is taken to the site to establish logistics of working in the

area. It is hoped that by working round the clock, the construction can be

completed in 12 months

The proximity to Chonga dam be established to calculate the pumpingrequirements of tailings effluent

A full sensitivity analysis be carried out using the attached spreadsheet to establish

how lucrative the project is

Negotiations be opened with second-hand equipment suppliers, like Manhattan in

South Africa, to establish the availability of such equipment

A consortium of financiers be approached to provide funding

The possibility of purchasing Old Dam. This dam is richer, but is geotechnically

unstable, as it was built in a swamp to combat blackwater fever when the mine

started in the 1930s. Should it break and block the Fisansa stream, the

environmental council will shut down the operation. However, there is a judicious

way of mining the tailings without causing breakage

Establishing the above, will improve on the accuracy of this management brief,

which is currently only 20%

Figure 8: The ultimate objective of the proposed project

Ramoutar (Ken) Seecharran

Mining/Metallurgical Consultant

Documents

Luanshya Akatiti Dam