|
The paragraphs above have shown some technical parameters that let obse
rve the efficiency offered by a cyanidation plant employing a CIL process. Now, will be analyzed some economical aspects between a Heap leaching and a CIL processes. For this analysis we will consider a small plant treating an auriferous ore at the rate of 100 ton per day. The gold content is 18 g/t and recovery are 60 y 90% by heap leaching and CIL, respectively. In each case with can have the following costs:
Table 4. Heap leaching and CIL costs.
|
Item
|
Heap Leaching (U.S.$)
|
CIL (U.S.$)
|
|
Equipment
|
1,000,000
|
2,000,000
|
|
Installation
|
225,000
|
500,000
|
|
Buildings
|
90,000
|
200,000
|
|
Services
|
70,000
|
200,000
|
|
Contingencies
|
135,000
|
300,000
|
|
Total
|
1,520,000
|
3,200,000
|
|
Operative cost ($/t)
|
28
|
34
|
Observing the results, it is easily note a higher cost for a CIL process. This is due to the energy taken by the mill and agitation system for the tanks. Nevertheless, considering the efficiency offered by each alternative, we can have the following results:
Table 5. Costs based on efficiency of each process.
|
Item
|
Heap Leaching (U.S.$)
|
CIL (U.S.$)
|
|
Investment
|
1,520,000
|
3,200,000
|
|
Operative cost ($/t)
|
28
|
34
|
|
Gold produced (kg/month)
|
32.4
|
48.6
|
|
Operative cost ($/oz produced)
|
80.63
|
65.27
|
|
Investment ($/oz produced)
|
1459
|
2047
|
|
Incomes ($/month)
|
416,720
|
625,080
|
The results obtained indicate that the operative cost for a CIL process is lower than a Heap Leaching process and the initial investment is higher against a CIL process but that difference can be covered with the major efficiency offered by CIL. Considering a gold price of U.S.$ 400 per ounce, the incomes have a difference of U.S.$ 208,360. In other words CIL gives better production and incomes. |
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