COST OF DILUTION

One of the main effects of ore dilution is the reduction of the mill feed grade. Lower mill feed grade means less revenue. Prove ore grade equation to be used. (7 points)

1. Complete the following table, given that dilution can be calculated by the following equation:

% Dilution= Waste tonnesOre tonnes+Waste tonnes X 100

Effect of Dilution on a Gold Ore
Ore Grade	Waste Grade	Dilution	Mill Feed
Au	Au		Au
(g/tonne)	(g/t)	(%)	(g/t)
0.5	0.0	0.0	0.5
0.5	0.0	10
0.5	0.05	10
0.4	0.05	10

2. Given the following information, calculate the cost of dilution (i.e. revenue loss) per day at this operation.

Daily Mill feed (constant): 2050 tonnes per day

Mill Recovery: 91%

Undiluted gold average grade: 0.5 g/tonne

Average gold grade of dilution material: 0.05 g/tonne

Dilution: 10%

Gold selling price: $1250/oz