Estimates of Operation Costs for Heap Leaching of 1,000 tm

ITEM: Transport (includes loading and unloading of the floor)
Cost (US$/TM): 1.10

ITEM: Crushing (two stages)
Cost (US$/TM): 0.80

ITEM: Aglomeration (includes 5.0 kg cement/TM)
Cost (US$/TM): 0.65

ITEM: Lixiviation and adsorption (1,0 Kg. NaCN/TM)
Cost (US$/TM): 3.25

ITEM: Desorption, regeneration, electro-obtaining
Cost (US$/TM): 0.35

ITEM: Chemical Analysis
Cost (US$/TM): 0.30

ITEM: Other (indirect and fixed expenses)
Cost (US$/TM): 0.45

TOTAL (By TM of the mineral) US$: 6.90

The costs of operation are very sensible to the consumption of the cyanide (US$2.2 for every Kg NaCN/TM) for which they can result considerably higher for consumptions superior to what is supposed, although, on the other hand, every NaCN, in a way that the the importance which the law of the mineral has is autoexplainable. To the previous estimate one would have to add the costs of mining extraction, payment by credit (if there is one at all), and depreciation of the equipment and machinery. This final one, considering a global investment of US$ 250,000 and eight years of useful life, would be that of US$ 1.74/TM, the price is more for countable purposes, due to the fact that in the practice there would be a use of more time. On the other hand, it can happen that the project would last less and, in such a case, portable units of crushing would be used, aglomeration, adsorption, etc., which would posteriorly be used in exploiting other small deposits. In whichever form, the recuperation of only 2 g. of gold by processed TM is already attractive for the total costs of production as high as US$ 20/TM, with a return of the investment in three years (US$390/Oz.tr.Au).