eng.monash.edu.au/enveng dr gavin m mudd environmental engineering sustainability metrics of gold...
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eng.monash.edu.au/enveng
Dr Gavin M MuddDr Gavin M MuddEnvironmental EngineeringEnvironmental Engineering
Sustainability Metrics Sustainability Metrics of Gold Miningof Gold Mining
February 2007February 2007
2nd Int Conf on Sustainability Eng/Sci : Sustainability Metrics of Gold Mining / 2Institute for Sustainable Water Resources
Gold …Gold …
2nd Int Conf on Sustainability Eng/Sci : Sustainability Metrics of Gold Mining / 3Institute for Sustainable Water Resources
Gold Mining v Sustainability ?Gold Mining v Sustainability ?
• Define oxymoron : sustainable gold miningDefine oxymoron : sustainable gold mining• Gold mining has been a critical aspect of Gold mining has been a critical aspect of
economic and social development in many economic and social development in many countriescountries
• Gold mining has also left a legacy of Gold mining has also left a legacy of impacts – social, environmental, etcimpacts – social, environmental, etc
• The application of sustainability principles The application of sustainability principles to gold mining is, at first, counter-intuitiveto gold mining is, at first, counter-intuitive
• This paper attempts to compile such data !This paper attempts to compile such data !
2nd Int Conf on Sustainability Eng/Sci : Sustainability Metrics of Gold Mining / 4Institute for Sustainable Water Resources
Gold Mining & Sustainability MetricsGold Mining & Sustainability Metrics
• Data Sources and MethodologyData Sources and Methodology• Analysis of Sustainability MetricsAnalysis of Sustainability Metrics• Results – Global Gold ProductionResults – Global Gold Production• Results – Energy, Water and Cyanide Results – Energy, Water and Cyanide
ConsumptionConsumption• Results – Greenhouse EmissionsResults – Greenhouse Emissions• Discussion : Deficiencies, Future Work …Discussion : Deficiencies, Future Work …• SummarySummary
2nd Int Conf on Sustainability Eng/Sci : Sustainability Metrics of Gold Mining / 5Institute for Sustainable Water Resources
Analysis of Sustainability MetricsAnalysis of Sustainability Metrics
• Some key issues for sustainability include Some key issues for sustainability include energy, water and cyanide consumption energy, water and cyanide consumption and greenhouse emissionsand greenhouse emissions
• The ‘eco-efficiency’ of various gold mines The ‘eco-efficiency’ of various gold mines is compared using the unit consumption is compared using the unit consumption (/emission) per gold produced relative to (/emission) per gold produced relative to ore grade and ore throughput :ore grade and ore throughput :– kL water / kg Au; t COkL water / kg Au; t CO22 / kg Au; GJ energy / kg Au / kg Au; GJ energy / kg Au
– kL water / t ore; t COkL water / t ore; t CO22 / t ore; GJ energy / t ore / t ore; GJ energy / t ore
– t cyanide / kg Aut cyanide / kg Au
2nd Int Conf on Sustainability Eng/Sci : Sustainability Metrics of Gold Mining / 6Institute for Sustainable Water Resources
Global Historical Gold ProductionGlobal Historical Gold Production
0
250
500
750
1,000
1,250
1,500
1,750
2,000
2,250
2,500
2,75018
40
1850
1860
1870
1880
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
Go
ld P
rod
uc
tio
n (
t A
u)
Rest of the World
United States
South Africa
Canada
Australia
United States - California
Australia - Eastern States
South Africa(Witwatersrand)
Australia -Western Australia
Gold price rise,Carbon-in-pulp developed
major world expansion of gold mining
AustraliaCanada
USA
South Africa
Rest ofthe World
2nd Int Conf on Sustainability Eng/Sci : Sustainability Metrics of Gold Mining / 7Institute for Sustainable Water Resources
Global Historical Gold Ore GradesGlobal Historical Gold Ore Grades
0
5
10
15
20
25
30
35
40
1830 1845 1860 1875 1890 1905 1920 1935 1950 1965 1980 1995
Go
ld G
rad
e (
g/t
Au
)
Brazil
USA
South Africa
Australia
Canada
2nd Int Conf on Sustainability Eng/Sci : Sustainability Metrics of Gold Mining / 8Institute for Sustainable Water Resources
Unit Water Consumption v GradeUnit Water Consumption v Grade
0
1,500
3,000
4,500
6,000
7,500
0 10 20 30 40 50
Gold Grade (g/t Au)
Wa
ter
Co
ns
um
pti
on
pe
r G
old
Pro
du
ced
(k
L/k
g A
u)
Africa
Asia-Pacific
Australia
Canada
Central & South America
United States
Canada - (82.4, 51.6)
Asia-Pacific (4.27, 8,342; 5.11, 9,442)
2nd Int Conf on Sustainability Eng/Sci : Sustainability Metrics of Gold Mining / 9Institute for Sustainable Water Resources
Unit Water Consumption v OreUnit Water Consumption v Ore
0
1
2
3
4
5
6
7
8
9
0 5 10 15 20 25 30 35 40 45
Ore Milled (Mt/yr)
Wa
ter
Co
ns
um
pti
on
pe
r t
Ore
Mil
led
(k
L/t
ore
)
Africa
Asia-Pacific
Australia
Canada
Central & South America
United States
Asia-Pacific (1.97, 28.0; 2.35, 48.0; 2.91, 38.9; 3.41, 32.6; 4.09, 43.0)Africa - (12.87, 21.33)
United States - (59.6, 0.088)& (63.2, 0.102)
2nd Int Conf on Sustainability Eng/Sci : Sustainability Metrics of Gold Mining / 10Institute for Sustainable Water Resources
Unit Energy Consumption v GradeUnit Energy Consumption v Grade
0
100
200
300
400
500
600
700
0 10 20 30 40 50
Gold Grade (g/t Au)
En
erg
y C
on
su
mp
tio
n p
er
Go
ld P
rod
uc
ed (
GJ
/kg
Au
)
Africa
Asia-Pacific
Australia
Canada
Central & South America
United States
Central & South America - (0.64, 1,076)
Canada - (82.4, 21.9)& (77.1, 22.9)
2nd Int Conf on Sustainability Eng/Sci : Sustainability Metrics of Gold Mining / 11Institute for Sustainable Water Resources
Unit Energy Consumption v OreUnit Energy Consumption v Ore
0
0.5
1
1.5
2
2.5
3
0 5 10 15 20 25 30 35 40 45
Ore Milled (Mt/yr)
En
erg
y C
on
su
mp
tio
n p
er
t O
re M
ille
d (
GJ
/t o
re)
Africa
Asia-Pacific
Australia
Canada
Central & South America
United States
Africa - (0.98, 3.87)
United States - (59.6, 0.042)& (63.2, 0.038)
2nd Int Conf on Sustainability Eng/Sci : Sustainability Metrics of Gold Mining / 12Institute for Sustainable Water Resources
Unit Cyanide Consumption v GradeUnit Cyanide Consumption v Grade
0
100
200
300
400
500
600
700
800
900
1,000
1,100
0 2 4 6 8 10 12 14 16 18
Gold Grade (g/t Au)
Cy
an
ide
Co
ns
um
pti
on
pe
r G
old
Pro
du
ce
d (
kg
CN
/kg
Au
)
Africa
Asia-Pacific
Australia
Canada
Central & South America
United States
2nd Int Conf on Sustainability Eng/Sci : Sustainability Metrics of Gold Mining / 13Institute for Sustainable Water Resources
Unit Greenhouse Emissions v GradeUnit Greenhouse Emissions v Grade
0
10
20
30
40
50
0 10 20 30 40 50
Gold Grade (g/t Au)
CO
2 E
mis
sio
ns
pe
r G
old
Pro
du
ce
d (
t C
O2/k
g A
u)
Africa
Asia-Pacific
Australia
Canada
Central & South America
United States
Central & South America - (0.64, 76.7)
Canada - (82.4, 0.2)& (77.1, 0.2)
2nd Int Conf on Sustainability Eng/Sci : Sustainability Metrics of Gold Mining / 14Institute for Sustainable Water Resources
Unit Greenhouse Emissions v OreUnit Greenhouse Emissions v Ore
0
50
100
150
200
250
0 10 20 30 40 50 60 70
Ore Milled (Mt/yr)
CO
2 E
mis
sio
ns
pe
r t
Ore
Mil
led
(k
g C
O2/
t o
re)
Africa
Asia-Pacific
Australia
Canada
Central & South America
United States
2nd Int Conf on Sustainability Eng/Sci : Sustainability Metrics of Gold Mining / 15Institute for Sustainable Water Resources
Discussions & Debates ..Discussions & Debates ..
• Gold mining has occurred throughout the Gold mining has occurred throughout the world, with main factors including :world, with main factors including :– new discoveries, prices, technology, social, …new discoveries, prices, technology, social, …
• The most recent gold boom (>1980) has The most recent gold boom (>1980) has seen unprecedented global gold miningseen unprecedented global gold mining
• Fundamental trends for gold mining :Fundamental trends for gold mining :– declining ore grades, open cuts, technology, …declining ore grades, open cuts, technology, …
• Sustainability metrics, unit consumption/ Sustainability metrics, unit consumption/ emissions, are highly grade dependentemissions, are highly grade dependent
2nd Int Conf on Sustainability Eng/Sci : Sustainability Metrics of Gold Mining / 16Institute for Sustainable Water Resources
Sustainability ‘Costs’ of GoldSustainability ‘Costs’ of Gold
• In general, based on data within this paper, In general, based on data within this paper, the production of gold entails :the production of gold entails :
per t Oreper t Ore per kg Auper kg Au
WaterWater 1.69 kL / t ore1.69 kL / t ore 773 kL / kg Au773 kL / kg Au
EnergyEnergy 0.34 GJ / t ore0.34 GJ / t ore 149 GJ / kg Au149 GJ / kg Au
CyanideCyanide -- 147 kg / kg Au147 kg / kg Au
Carbon Carbon DioxideDioxide
23.4 kg CO23.4 kg CO22 / t / t
oreore11.6 t CO11.6 t CO22 / t ore / t ore
2nd Int Conf on Sustainability Eng/Sci : Sustainability Metrics of Gold Mining / 17Institute for Sustainable Water Resources
Summary & ConclusionsSummary & Conclusions
• Gold Mining continues around the worldGold Mining continues around the world
• Gold ore grades are in terminal declineGold ore grades are in terminal decline
• Sustainability metrics are clearly linked and Sustainability metrics are clearly linked and very sensitivevery sensitive to ore grade to ore grade
• Due to the low grade, gold production Due to the low grade, gold production entails significant unit costs for water, entails significant unit costs for water, energy, cyanide, greenhouse emissionsenergy, cyanide, greenhouse emissions
• Future sustainability is difficult to predict …Future sustainability is difficult to predict …
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