TECHNO-ECONOMIC EVALUATION OF SEAWATER USE IN FLOTATION OF COPPER
ORE
Nawshad Haque, Joseph Cho, Leanne Smith, Hal Aral and Warren Bruckard
CSIRO Mineral Resources Flagship
Private Bag 10, Clayton South, Vic 3168 Australia
Corresponding author’s email: Nawshad.Haque@csiro.au
ABSTRACT
Water availability is one of the principle parameters to determine feasibility of mining projects in arid and
semi-arid regions. The consumptive volumetric water footprint (VWF) from a conceptual model was found
to be 2.45 t/t Cu ore, compared with an actual measurement reported in the literature of 2.72 t/t Cu ore. The
flowsheet includes mineral processing stages such as crushing, screening, grinding, classification,
separation, flotation, thickening and filtration. The effect of a number of variables on the VWF was
evaluated. These variable included solid/liquid ratio, feed mass flowrate (tonne/hour), ore loss (%), water
loss (%), moisture content (%) of ore, ore grade (%) and water recycling (%). The use of raw seawater
provided the greatest environmental and economic advantage among several scenarios assessed. This study
assumed a price of $1/kL freshwater, $4/kL for transport over a 200 km distance at 2000 m altitude and
$4/kL water treatment. The water related cost of the raw seawater use scenario was A$247/t Cu in
concentrate, while the water related costs of fresh water, desalinated water and blended water scenarios
were A$309/t, A$494/t and A$430/t, respectively. Despite the fact that recycling water reduces VWF up to
85%, the cost of reduction was ranged between 0% and 39%. It was observed that the water related cost
(fresh water scenario) accounted for 44% to 49% of the entire mining and processing costs including
drilling, blasting, loading, hauling, crushing, grinding and concentrating. The total costs were A$636/t Cu
in concentrate for the no recycling case and A$588/t Cu in concentrate for the 85% recycling of water.
Drilling
6%
Water
44%
Blasting
8%
Loading & Hauling
17%
Crushing
1%
Concentrating
15%
Grinding
9%
Figure 1 – Contributions from various inputs on the operating cost per tonne of copper concentrate
($635.5/t Cu concentrate) – base case
KEYWORDS
Seawater, flotation, copper ore, techno-economic evaluation, flowsheeting