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Part 2: GHG Emissions in Gold Mining - Australia in Depth BY: Sam Ulrich Principal Consultant May 2020
Part 2: GHG Emissions in Gold Mining -Australia in Depth
BY: Sam UlrichPrincipal Consultant
May 2020
Study Published in 2020
Greenhouse Gas Emissions and Production Cost Footprints in Australian Gold MinesUlrich, Trench & HagemannJournal of Cleaner Productionhttps://doi.org/10.1016/j.jclepro.2020.122118
2
Gold Production
Gold Grade
All-in Sustaining Costs(AISC)
Energy Consumption
GHG EmissionsScope 1Scope 2
Study Period 1 January 2014 to 30 June 2018
Australia GHG Emissions Intensity Curve – 30 June 2018
3
1. Gwalia; 2. Mt Carlton; 3. Agnew; 4. Granny Smith; 5. Tanami; 6. Peak; 7. Fosterville; 8. Carosue Dam; 9. Cracow; 10. Sunrise Dam; 11. Mount Monger; 12. St Ives; 13. Combined Jundee, Kalgoorlie and Paulsens; 14. Tropicana; 15. Combined Duketon North and South; 16. Plutonic; 17. Combined Central Murchison, Fortnum, Higginsville and South Kalgoorlie; 18. Tomingley; 19. Kalgoorlie (KCGM); 20. Mungari; 21. Combined Mt Magnet Operations and Edna May; 22. Thunderbox; 23. Matilda-Wiluna; 24. Paddington; 25. Cadia Valley; 26. Darlot; 27. Ravenswood; 28. Boddington; 29. Telfer; 30. Mt Rawdon; 31. Cowal.
Lowest Quartile≤513 kg CO2-e/oz
94% underground gold
Median619 kg CO2-e/oz
Highest Quartile≥811 kg CO2-e/oz58% open pit gold
Relationships – GHG Emissions Intensity, Costs & Gold Grade
4
0
200
400
600
800
1,000
1,200
1,400
1,600
0 200 400 600 800 1,000 1,200 1,400 1,600
Real A
ISC
(U
S$/o
z)
GHG Emissions Intensity (kg CO2-e/oz AuEq)
0
200
400
600
800
1,000
1,200
1,400
1,600
0 200 400 600 800 1,000 1,200 1,400 1,600
Real A
ISC
(U
S$/o
z)
GHG Emissions Intensity (kg CO2-e/oz AuEq)
UG
OP & UG
OP
Outlier
Low Cost
Low GHG
High Grade
Low Cost
High GHG
Low Grade
High Cost
High GHG
Low Grade
High Cost
Low GHG
High Grade
Cadia
Mean AISC
Mean G
HG
em
issio
ns
Mt Carlton
Edna May
Telfer
Boddington
Gwalia
Sunrise Dam
Circle size represents gold grade
Simple Relationships ExistHigher grade → Lower GHG emissions intensity
Higher grade → Lower costs
OutliersFosterville & Stawell mines
Victorian grid electricity – Brown Coal
Energy SourceImportant to understand each mines
main sources of energy
Energy Sources in Australian Gold Mines (30 June 2018)
5
Grid39%
Gas29%
Diesel21%
Hybrid11%
Dual Fuel
Onsite Electricity Grid Electricity
Renewables30 June 2018 – In Development
Present - Operating
Energy Intensity – Relationships and Reporting Issues
6
0
5
10
15
20
25
0 200 400 600 800 1,000 1,200 1,400 1,600
Energ
y I
nte
nsity (
GJ/o
z A
uE
q)
GHG Emissions Intensity (kg CO2-e/oz AuEq)
Gas
R2 = 0.955
Diesel
R2 = 0.960
Grid
R2 = 0.830
Grid
Gas
Diesel
Hybrid
Outlier
0
5
10
15
20
25
0 2 4 6 8 10 12 14
Energ
y I
nte
nsity (
GJ/o
z A
uE
q)
Average Gold Head Grade (g/t)
Gas
R2 = 0.929Grid
R2 = 0.723
Diesel
R2 = 0.903
Grid
Gas
Diesel
Hybrid
Outlier
Energy Intensity (GJ/oz)
Relationship – Energy intensity to Au grade
Reporting issues!
Relationship – Energy intensity to GHG emissions intensity
Calorific energy versus utilised mechanical energy Grid supplied energy has highest
carbon intensity
0
200
400
600
800
1,000
1,200
1,400
1,600
0 200 400 600 800 1,000 1,200 1,400 1,600
Real A
ISC
(U
S$/o
z)
GHG Emissions Intensity (kg CO2-e/oz AuEq)
0
200
400
600
800
1,000
1,200
1,400
1,600
0 200 400 600 800 1,000 1,200 1,400 1,600
Real A
ISC
(U
S$/o
z)
GHG Emissions Intensity (kg CO2-e/oz AuEq)
GHG Emissions Intensity – Cost Footprints by Ore Source
7
0
200
400
600
800
1,000
1,200
1,400
1,600
0 200 400 600 800 1,000 1,200 1,400 1,600
Real A
ISC
(U
S$/o
z)
GHG Emissions Intensity (kg CO2-e/oz AuEq)
Me
an
GH
G e
mis
sio
ns
Mean G
HG
em
issio
ns
Me
an
GH
G e
mis
sio
ns
Mean AISC
Mean AISC
Mean AISC
Low Cost
Low GHGLow Cost
High GHG
High Cost
High GHG
High Cost
Low GHG
Low Cost
Low GHG
Low Cost
High GHG
High Cost
High GHG
High Cost
Low GHG
Low Cost
Low GHG
Low Cost
High GHG
High Cost
High GHG
High Cost
Low GHG
OP & UGOP UG
Box is one standard deviation from the mean AISC and mean GHG emissions intensity
777
787
648
1,007920
471
Different GHG Emissions Intensity Production Cost Footprints by Ore Source
Open Pit Open Pit & Underground Underground
Relationship – Emissions Intensity, AISC with Mined Ore Source
8
Indicative life of a 20 year gold mine
Similar increases and decreases in costs and GHG emissions intensity observed in
other countries
18
27
40
30
18
9
Perc
enta
ge C
han
ge
0
10
20
30
-10
-20
-30
-40
AIS
C
AIS
C
AIS
C
Emis
sio
ns
Inte
nsi
ty
Emis
sio
ns
Inte
nsi
ty
Emis
sio
ns
Inte
nsi
ty
Phase 1 to 2 Phase 2 to 3 Phase 1 to 3
0
200
400
600
800
1,000
1,200
0
100
200
300
400
500
600
700
800
900
0 2 4 6 8 10 12 14 16 18 20
Real A
ISC
(U
S$/o
z)
GH
G Inte
nsity (
kg C
O2-e
/oz A
uE
q)
Years
Phase 1OP Mining
Phase 2OP & UG Mining
Phase 3UG Mining
Mean Real AISC
Mean GHG Emissions Intensity
Declining Gold Grades – Impact on GHG Emissions Intensity
1991-2006 Study Average
40
%
2014-2018Study Average
19,800 kg CO2-e/kg Au
14,100 kg CO2-e/kg Au2006 - 2.44 g/t Au
2017 - 1.83 g/t Au
Forecast2029 - 1.02 g/t Au
49
%
32
%
34
%
OP
UGOP & UG
2029Forecast GHG
Emissions Intensity
Varies by ore source
9
0
200
400
600
800
1,000
1,200
1,400
0 2 4 6 8 10 12
GH
G E
mis
sio
ns In
ten
sity (
kg
CO
2-e
/oz A
uE
q)
Average Gold Head Grade (g/t)
OP
OP & UG
UG
Stay Tuned For Future Presentations In The Series
10
Globally Carbon Price A Greener Future
GHG Emissions in Gold Mining
Paper
For more information contact: [email protected]
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