18: Mineral Processing and Metallurgical Testing
The author has copies of two Dynacor mill reports given to him by Marcial
Portocarrero, one of the informales who used to work the C1 vein at Zona
Canchete. The reports are dated August 3, 2003, and pertain to Lot 15 (0.7 metric
tonnes grading 1.687 oz/t) and Lot 16 (3.468 metric tonnes grading 0.681 oz/t)
from Zona Canchete. According to the mill report, 90% of the gold was recuperated
from the material submitted using standard carbon-in-pulp recovery process.
According to mill reports, reproduced in Appendix 3, custom milling charges range
from $65/t for the lower-grade material (0.68 oz/t) to $80/t for the higher-grade
material (1.69 oz/t).
The above is taken from our 2005 Tech report. As you can see, at that time, the cost to mill the high grade ore cost approx 23 % more, than the cost to mill the low grade ore. This is because of the metalurgical processes I touched on before in an earlier post. To make things simple, the rust/gold (oxidized)situation is easier to recover the gold from than the unoxidized ore.
Sometimes in deposits, there are different minerals all together, if the company chooses to save another mineral on top of the gold, say copper for simplicities sake, then the processes would be slightly different and have a different cost.
Nevertheless, these prices will most likely not affect us and an average could be drawn up.
IMO
