This document discusses the declining ore grades in Australian mines and the implications for processing routes and energy consumption. As ore grades decrease over time, the energy required for mining and processing increases significantly. Processing routes like heap leaching and direct smelting consume less energy than routes involving concentration and smelting, especially for lower grade ores. The optimal processing route depends on the ore grade and characteristics. Overall, declining ore grades will continue to drive up energy needs for metal production in Australia and globally.

1. Low Grade Ores
- Smelt, leach or concentrate?
1
Sharif Jahanshahi and Terry Norgate
Meta-Logical Solutions

2. Decline in Australian Ore Grades
2
0
5
10
15
20
25
30
35
40
1840 1855 1870 1885 1900 1915 1930 1945 1960 1975 1990 2005
OreGrades(Cu,Pb,Zn,Au,Ni,U,Diamonds)
0
325
650
975
1,300
1,625
1,950
2,275
2,600
OreGrade(Ag)
Copper (%Cu)
Gold (g/t)
Lead (%Pb)
Zinc (%Zn)
Uranium (kg/t U3O8)
Nickel (%Ni)
Diamonds (carats/t)
Silver (g/t)
general trend
(kg/t U3O8)
(Ag, 1884 - 3,506 g/t)
Source: G. Mudd, The sustainability of mining in Australia: Key production trends and their environmental implications
for the future, Research Report, October 2007 (http://civil.eng.monash.edu.au/about/staff/muddpersonal/rr5/

3. Processing Routes for Copper Ores
Ore deposit
Mining
Crushing & grinding
Mineral processing
Smelting
Converting
Refining
Refined metal
Smelting
Pyrometallurgical
route
Hydrometallurgical
route
In-situ leaching
Leaching (heap, pressure)
Solvent extraction &
electrowinning
Refined metal
Crushed/ground ore
Matte
Crushed/ground ore
Concentrate
Matte

4. LCA Based Energy Consumption
- Excludes mining
-
5,000
10,000
15,000
20,000
25,000
Concentrator Smelter Refinery Total
Energyconsumption(MJ/tCu)
Ore grade 3% Cu
Concentrate recovery 93.7%
Smelterrecovery 97.1%
Overallrecovery 90.5%
-
10,000
20,000
30,000
40,000
50,000
Crushing Leach & SX EW TotalEnergyconsumption(MJ/tCu)
Ore grade 2% Cu
Heapleach recovery 70%
SXrecovery 93%
Overallrecovery 64.8%
Concentrate, Smelt, Refine Heap leach, SX, EW
Energy consumption will increase with
decreasing ore grade through the concentrator
and mining
Energy consumption will increase
with decreasing ore grade through
leaching and mining

5. Effect of Ore Grade on Energy Consumption
- Pyromet route
0
100
200
300
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
Embodiedenergy(MJ/kgCu)
Ore grade (% Cu)
Liberation/grain size 75 um
Australia
World
USA

6. Effect of Ore Grade - Including Mining
0
30
60
90
120
150
0.5% Cu 3.0% Cu
Embodiedenergy(MJ/kgCu)
Refining
Smelting
Mineral processing
Mining
6 times higher energy consumption for mining and mineral processing

7. Comparison of Alternative Routes
0
400
800
1200
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Embodiedenergy(MJ/kgCu)
Ore grade (wt% Cu)
Smelt & conc (75 um)
Smelt & conc (5 um)
Pressure acid leach
In-situ leaching
Heap leaching
Direct smelt
❖ With waste heat recovery from slags, direct smelting becomes even
more energy efficient

8. Presentation by Sharif Jahanshahi PhD, FAusIMM
 Sharif Jahanshahi has over 30 years experience in
R&D across; high temperature processing of
ferrous and base metals, thermodynamics and
kinetics of high temperature systems, melt
chemistry, process modelling, simulation and
development
 Currently consulting for leading global players in
the metallurgical industry through Meta-Logical
Solutions Pty Ltd.
Website: http://www.metalogical.solutions
Email: sharif@metalogical.solutions