Introduction To Caving 4k4w40
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An Introduction to Block and Caving Allan Moss, General manager Rio Tinto Copper Projects
Agenda
Context – why the interest in caving How block caving works and key technical considerations Risks Value drivers
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
2
Greater Depths of Mining
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
3
Trends in Mining ~ to 2013
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
4
Trends in Mining ~ after 2013
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
5
Why Caving? • Use of gravity to break the rock (instead of explosives), thus low operating cost compared with other underground methods • High production rates can be achieved allowing economies of scale • Allows high degree of mechanization • Safe However • High initial capital costs • Conceptually simple – let gravity do the work - but technically very challenging • Requires large design effort; high quality construction; and rigorously managed operations 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
6
Cave Mining ~ When is it Applicable? •
Orebodies with a substantial vertical dimension; massive or pipe like
•
Rock strength not a limitation but need sufficient orebody dimensions
•
Primarily used in copper mining but also molybdenum and diamonds,
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
7
Evolution of daily production rates New generation Caves; under construction
100000 80000 60000
3000m
Western Deeps
2000m
Kidd Creek
Homestake - S Dakota
Magma
120000
TONNES PER DAY
1000m
Henderson
140000
Palabora
160000
Open pits
4000m
San Manuel Climax
40000
Malmberget Premier Kidd Creek Salvador
Miami Mount Isa
1900
1920
1940
1960
1980
YEAR 1 March 2011
Henderson Andina
Kiruna
20000 0 1880
Super caves
BMO Capital Markets 2011 Global Metals & Mining Conference
“Conventional” underground
Olympic Dam Palabora Freeport IOZ/DOZ Ridgeway
2000
2020
2040
(after Brown 2004a) 8
Modernisation of an Old Method
LHD Grizzley Block Block Cave Cave 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
9
With Increasing Production comes need for Size Questa
DOZ
Perseverance
Parkes
Henderson
Premier
San Manuel
Oyu Tolgoi
Palabora
Resolution
Waste Unexploited resource Caved waste Exploited resource
1 March 2011
Note: size is for illustrative purpose only and has been sourced from published information BMO Capital Markets 2011 Global Metals & Mining Conference
10
Major block and cave mines
1 March 2011
Rio Tinto Planned Currently operating Closed mines BMO Capital Markets 2011 Global Metals & Mining Conference
11
Rio Tinto – a leader in cave mining • Involved in 5 block caves in operation or development • Applying experience from operating mines to developing next generation block cave mines • Advancing technology and innovation in block cave mining • Building an Underground Technology Centre to ensure objectives are met, particularly with regard to people 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
12
Agenda
Context – why the interest in caving How block caving works and key technical considerations Risks Value drivers
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
13
Where Does Caving fit in the Spectrum of Underground?
1 March 2011
Method
T / Manshift
Avg. T / Day
Relative Operating Cost per tonne
Resuing
0.2 - 0.5
50 - 100+
70+
Cut and Fill
12 - 48
500 – 1,500
20 to 70
Shrinkage
20 - 28
200 - 800
20 to 50
Room and Pillar
15 - 150
1,500 – 10,000
7 to 20
Open Stoping
20 - 115
1,500 – 25,000
7 to 25
Sub-level Caving
65 - 180
1,500 – 50,000
7 to 17
Block Caving
300 - 2000
10,000 – 100,000
1 to 2.5
BMO Capital Markets 2011 Global Metals & Mining Conference
Underground mining methods modified from Brown, 2003
14
Five Key Components of a Cave Mine •
Orebody access Undercut Level – Shafts – Tunnels Extraction Level
•
Orebody
Undercutting Vent Raise
– The level where caving is initiated •
Ore
Extraction
Exhaust Level
– Where ore is removed from the broken rock •
Ore flow – Sizing and transfer of ore to surface
•
Haulage Level Infrastructure
– systems, ventilation, power, water, supplies, men 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
15
Block Cave Concept Plant Crushed Ore
Shaft Ore body
Draw bells
Production tunnels
1 March 2011
Haulage system
BMO Capital Markets 2011 Global Metals & Mining Conference
16
Caving Process
•
20
•
Progressive spalling
25
35
1. Develop undercut level 2. Develop production tunnels 1 March 2011
Block cave mining is based on the principle that, once a sufficiently large area of a block has been undercut by drilling and blasting, the overlying block of ore will start to cave under the influence of gravity. The process will continue until caving propagates through the entire block to surface or to the open pit above
45
3. Drill and blast undercut rings 4. Open troughs
BMO Capital Markets 2011 Global Metals & Mining Conference
17
What are we trying to achieve?
Caved Ground
Undercut
Extraction LHD Loading 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
18
Block Caving Concept VALUE REALIZATION CAPITAL INVESTMENT 100 %
Vyazmensky © 2007
$ CAVE DYNAMICS SOURCES OF UNCERTAINTY
TIME CAVE MANAGEMENT 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
19
Section Through Cave
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
20
Key Technical Issues
cave propagation cave flow
1 March 2011
cave fragmentation
BMO Capital Markets 2011 Global Metals & Mining Conference
21
Critical dimensions to initiate caving
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
22
Geometry of drawbells
DRAWBELLS
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
23
Fragmentation: the key to a successful operation
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
24
Impacts of Fragmentation
PRODUCTIVITY
IMPLICATIONS ON RESOURCE RECOVERY
SECONDARY BLASTING
VALUE AT RISK 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
25
Caving the block Primary Fragmentation
Index of Interruptions Frequency (Salvador mine, draw point 04W20)
Secondary fragmentation
HoD
Initial secondary fragmentation Blasting effect Blasted undercut material
Secondary Fragmentation
Flow Interruption Index (events/tons x 1000)
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
26
Rock Structure and fragmentation
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
27
Fragmentation is complex: risks!!! zone of loosening
expansion void
Primary fragmentation
Secondary fragmentation
f(fragment size)
fragment size evolution with draw
higher mobility of finer fragments within a draw column
Fine material
Coarse material
IDZ
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
28
Cave Flow Zone of Loosening
Entry
waste ore
ore
HoD
waste
ore
ore
waste
Waste
(blocks that were displaced vertically at least once)
IDZ ~ Ellipsoid of Motion (extracted blocks) 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
29
Flow dictates Revenue Stream
WASTE ROCK
CAVED ORE UNCAVED ORE
WASTE ENTRY cylindrical IEZ
EXTRACTED ORE
RILLING and MASS FLOW 1 March 2011
elliptical or frustum shaped IEZ; height equivalent to~100-200 mean fragment size
PREDOMINATLY MASS FLOW
BMO Capital Markets 2011 Global Metals & Mining Conference
30
What do we draw?- the recovery issue High grade ore
Dilution entry
ORE BODY
$ WASTE ROCK
WASTE ROCK
TIME
Vyazmensky Vyazmensky © © 2008 2008
REPEAT 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
31
What do we draw?- the recovery issue High grade ore
Dilution entry
ORE BODY
$ WASTE ROCK
WASTE ROCK
TIME
Vyazmensky Vyazmensky © © 2008 2008
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
32
Undercutting UNCAVED ORE Rings to be blasted
CAVED ORE
Blasted undercut rings
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
33
Purpose of the Extraction Level
ALLOW DEVELOPMENT OF DRAWBELLS
1 March 2011
ACCESS TO ORE ABOVE
BMO Capital Markets 2011 Global Metals & Mining Conference
34
Light at the End of the Tunnel
A video of some of the concepts outlined can be found http://www.argylediamonds.com.au/video_block_cave.html 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
35
Agenda
Context – why the interest in caving How block caving works and key technical considerations Risks Value drivers
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
36
Can’t define risk - Can’t define value Block caving is not for marginal projects Complete knowledge of the future is an impossibility The question then becomes “how representative is the information we have on hand?” This information is used to develop a robust enough plan to cater for the inherent uncertainty. Uncertainty translates to risk (Flexibility costs money)
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
37
Differences in Knowledge therefore differences in Uncertainty
Initiation point close to surface Substantial information No geotechnical constraints Ore drilled and typically sampled as part of mining process – detailed knowledge for short term planning Initiation point remote from surface Limited information Substantial geotechnical constraints
Limited knowledge of ore- sampling after the fact
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
38
Scale
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
39
Access and Extraction Complexity DOZ Mine – Freeport, Indonesia
GBT Area I & II
Escondida, Chile IOZ
DOZ
Courtesy of PTFI 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
40
Control OPEN PIT MINING
CAVE MINING uncertainty
reduced knowledge well established method good control
limited control
more certainty BETTER TECHNOLOGY IS A KEY TO BETTER VALUE 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
41
Risk Characterisation – the resource; understanding the size of the prize Design – resource to reserve; time for imagination Construction – the big spend and first taste of reality Operation – recovery and payback Paper (Design) Value vs. Actual Value
1,5 m
CONCRETE DAMAGE
CONCRETE DAMAGE
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
42
Lesson learned at Palabora Palabora successfully transitioned from an open pit to a 30,000 tpd underground block cave but……. Surface subsidence
Mine infrastructure
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
dilution of the ore reserve and subsequent reduction in life of mine 43
Agenda
Context – why the interest in caving How block caving works and key technical considerations Risks Value drivers
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
44
Ore grade and value
Value is a function of Run of Mine (ROM) grade which is an outcome of three interrelated factors
1 March 2011
1. The resource grade; a measure of the metal that is in the ground 2. The reserve grade, a measure of the effectiveness of the design 3. The recovered grade, a measure of how the cave is managed and cave dynamics
BMO Capital Markets 2011 Global Metals & Mining Conference
45
Indicative Costs Capital
The capital and operating costs shown are relative and provide an indication of the spread. Both green field and brown field projects are included as are operations where access is via shaft or by decline. They were developed simply by normalising to lowest cost producers in of capital and operating cost.
Operating
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
46
How Soon do you Get your Money Back?
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
47
Realising Value New generation of Cave Mines • • •
represent a step change in the size of operations require investment levels of $2 to 10 billion and require significant time to achieve operating targets
There are value drivers common to any mining project: 1. Costs (capital and operating) 2. Revenue 3. Time 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
48
Investment in technology and innovation to drive value Cave dynamics • Block caving is inflexible and value locked in at the design phase • Important to understand cave behaviour and reliably forecast metal production (tons and grade)
Mine of the Future™
1 March 2011
Intelligent Mining • Autonomous equipment • Block cave operations well suited to concept of intelligent mining; real time information • Operating efficiencies
BMO Capital Markets 2011 Global Metals & Mining Conference
49
Investment in technology and innovation to drive value Rapid development • Tunnelling concepts that are more productive and cost effective than traditional methods • Integrated shaft boring machinery with the potential to dramatically improve safety while reducing construction time Optimised design and management • Building on ability to predict cave behaviour • Improved planning techniques and software to improve grade sequencing
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
50
The Vision – an Ore Factory Required Fragmentator
In Situ Crushing and Grinding
Fragment Size
Energy (Distance Traveled) Reliable Ore Flow Predictable Fragmentation (+ grade)
Ore Transport and Sizing
The The Ore RockFactory Factory
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
51
Thank You Allan Moss, General manager Rio Tinto Copper Projects
Agenda
Context – why the interest in caving How block caving works and key technical considerations Risks Value drivers
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
2
Greater Depths of Mining
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
3
Trends in Mining ~ to 2013
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
4
Trends in Mining ~ after 2013
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
5
Why Caving? • Use of gravity to break the rock (instead of explosives), thus low operating cost compared with other underground methods • High production rates can be achieved allowing economies of scale • Allows high degree of mechanization • Safe However • High initial capital costs • Conceptually simple – let gravity do the work - but technically very challenging • Requires large design effort; high quality construction; and rigorously managed operations 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
6
Cave Mining ~ When is it Applicable? •
Orebodies with a substantial vertical dimension; massive or pipe like
•
Rock strength not a limitation but need sufficient orebody dimensions
•
Primarily used in copper mining but also molybdenum and diamonds,
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
7
Evolution of daily production rates New generation Caves; under construction
100000 80000 60000
3000m
Western Deeps
2000m
Kidd Creek
Homestake - S Dakota
Magma
120000
TONNES PER DAY
1000m
Henderson
140000
Palabora
160000
Open pits
4000m
San Manuel Climax
40000
Malmberget Premier Kidd Creek Salvador
Miami Mount Isa
1900
1920
1940
1960
1980
YEAR 1 March 2011
Henderson Andina
Kiruna
20000 0 1880
Super caves
BMO Capital Markets 2011 Global Metals & Mining Conference
“Conventional” underground
Olympic Dam Palabora Freeport IOZ/DOZ Ridgeway
2000
2020
2040
(after Brown 2004a) 8
Modernisation of an Old Method
LHD Grizzley Block Block Cave Cave 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
9
With Increasing Production comes need for Size Questa
DOZ
Perseverance
Parkes
Henderson
Premier
San Manuel
Oyu Tolgoi
Palabora
Resolution
Waste Unexploited resource Caved waste Exploited resource
1 March 2011
Note: size is for illustrative purpose only and has been sourced from published information BMO Capital Markets 2011 Global Metals & Mining Conference
10
Major block and cave mines
1 March 2011
Rio Tinto Planned Currently operating Closed mines BMO Capital Markets 2011 Global Metals & Mining Conference
11
Rio Tinto – a leader in cave mining • Involved in 5 block caves in operation or development • Applying experience from operating mines to developing next generation block cave mines • Advancing technology and innovation in block cave mining • Building an Underground Technology Centre to ensure objectives are met, particularly with regard to people 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
12
Agenda
Context – why the interest in caving How block caving works and key technical considerations Risks Value drivers
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
13
Where Does Caving fit in the Spectrum of Underground?
1 March 2011
Method
T / Manshift
Avg. T / Day
Relative Operating Cost per tonne
Resuing
0.2 - 0.5
50 - 100+
70+
Cut and Fill
12 - 48
500 – 1,500
20 to 70
Shrinkage
20 - 28
200 - 800
20 to 50
Room and Pillar
15 - 150
1,500 – 10,000
7 to 20
Open Stoping
20 - 115
1,500 – 25,000
7 to 25
Sub-level Caving
65 - 180
1,500 – 50,000
7 to 17
Block Caving
300 - 2000
10,000 – 100,000
1 to 2.5
BMO Capital Markets 2011 Global Metals & Mining Conference
Underground mining methods modified from Brown, 2003
14
Five Key Components of a Cave Mine •
Orebody access Undercut Level – Shafts – Tunnels Extraction Level
•
Orebody
Undercutting Vent Raise
– The level where caving is initiated •
Ore
Extraction
Exhaust Level
– Where ore is removed from the broken rock •
Ore flow – Sizing and transfer of ore to surface
•
Haulage Level Infrastructure
– systems, ventilation, power, water, supplies, men 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
15
Block Cave Concept Plant Crushed Ore
Shaft Ore body
Draw bells
Production tunnels
1 March 2011
Haulage system
BMO Capital Markets 2011 Global Metals & Mining Conference
16
Caving Process
•
20
•
Progressive spalling
25
35
1. Develop undercut level 2. Develop production tunnels 1 March 2011
Block cave mining is based on the principle that, once a sufficiently large area of a block has been undercut by drilling and blasting, the overlying block of ore will start to cave under the influence of gravity. The process will continue until caving propagates through the entire block to surface or to the open pit above
45
3. Drill and blast undercut rings 4. Open troughs
BMO Capital Markets 2011 Global Metals & Mining Conference
17
What are we trying to achieve?
Caved Ground
Undercut
Extraction LHD Loading 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
18
Block Caving Concept VALUE REALIZATION CAPITAL INVESTMENT 100 %
Vyazmensky © 2007
$ CAVE DYNAMICS SOURCES OF UNCERTAINTY
TIME CAVE MANAGEMENT 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
19
Section Through Cave
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
20
Key Technical Issues
cave propagation cave flow
1 March 2011
cave fragmentation
BMO Capital Markets 2011 Global Metals & Mining Conference
21
Critical dimensions to initiate caving
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
22
Geometry of drawbells
DRAWBELLS
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
23
Fragmentation: the key to a successful operation
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
24
Impacts of Fragmentation
PRODUCTIVITY
IMPLICATIONS ON RESOURCE RECOVERY
SECONDARY BLASTING
VALUE AT RISK 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
25
Caving the block Primary Fragmentation
Index of Interruptions Frequency (Salvador mine, draw point 04W20)
Secondary fragmentation
HoD
Initial secondary fragmentation Blasting effect Blasted undercut material
Secondary Fragmentation
Flow Interruption Index (events/tons x 1000)
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
26
Rock Structure and fragmentation
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
27
Fragmentation is complex: risks!!! zone of loosening
expansion void
Primary fragmentation
Secondary fragmentation
f(fragment size)
fragment size evolution with draw
higher mobility of finer fragments within a draw column
Fine material
Coarse material
IDZ
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
28
Cave Flow Zone of Loosening
Entry
waste ore
ore
HoD
waste
ore
ore
waste
Waste
(blocks that were displaced vertically at least once)
IDZ ~ Ellipsoid of Motion (extracted blocks) 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
29
Flow dictates Revenue Stream
WASTE ROCK
CAVED ORE UNCAVED ORE
WASTE ENTRY cylindrical IEZ
EXTRACTED ORE
RILLING and MASS FLOW 1 March 2011
elliptical or frustum shaped IEZ; height equivalent to~100-200 mean fragment size
PREDOMINATLY MASS FLOW
BMO Capital Markets 2011 Global Metals & Mining Conference
30
What do we draw?- the recovery issue High grade ore
Dilution entry
ORE BODY
$ WASTE ROCK
WASTE ROCK
TIME
Vyazmensky Vyazmensky © © 2008 2008
REPEAT 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
31
What do we draw?- the recovery issue High grade ore
Dilution entry
ORE BODY
$ WASTE ROCK
WASTE ROCK
TIME
Vyazmensky Vyazmensky © © 2008 2008
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
32
Undercutting UNCAVED ORE Rings to be blasted
CAVED ORE
Blasted undercut rings
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
33
Purpose of the Extraction Level
ALLOW DEVELOPMENT OF DRAWBELLS
1 March 2011
ACCESS TO ORE ABOVE
BMO Capital Markets 2011 Global Metals & Mining Conference
34
Light at the End of the Tunnel
A video of some of the concepts outlined can be found http://www.argylediamonds.com.au/video_block_cave.html 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
35
Agenda
Context – why the interest in caving How block caving works and key technical considerations Risks Value drivers
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
36
Can’t define risk - Can’t define value Block caving is not for marginal projects Complete knowledge of the future is an impossibility The question then becomes “how representative is the information we have on hand?” This information is used to develop a robust enough plan to cater for the inherent uncertainty. Uncertainty translates to risk (Flexibility costs money)
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
37
Differences in Knowledge therefore differences in Uncertainty
Initiation point close to surface Substantial information No geotechnical constraints Ore drilled and typically sampled as part of mining process – detailed knowledge for short term planning Initiation point remote from surface Limited information Substantial geotechnical constraints
Limited knowledge of ore- sampling after the fact
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
38
Scale
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
39
Access and Extraction Complexity DOZ Mine – Freeport, Indonesia
GBT Area I & II
Escondida, Chile IOZ
DOZ
Courtesy of PTFI 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
40
Control OPEN PIT MINING
CAVE MINING uncertainty
reduced knowledge well established method good control
limited control
more certainty BETTER TECHNOLOGY IS A KEY TO BETTER VALUE 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
41
Risk Characterisation – the resource; understanding the size of the prize Design – resource to reserve; time for imagination Construction – the big spend and first taste of reality Operation – recovery and payback Paper (Design) Value vs. Actual Value
1,5 m
CONCRETE DAMAGE
CONCRETE DAMAGE
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
42
Lesson learned at Palabora Palabora successfully transitioned from an open pit to a 30,000 tpd underground block cave but……. Surface subsidence
Mine infrastructure
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
dilution of the ore reserve and subsequent reduction in life of mine 43
Agenda
Context – why the interest in caving How block caving works and key technical considerations Risks Value drivers
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
44
Ore grade and value
Value is a function of Run of Mine (ROM) grade which is an outcome of three interrelated factors
1 March 2011
1. The resource grade; a measure of the metal that is in the ground 2. The reserve grade, a measure of the effectiveness of the design 3. The recovered grade, a measure of how the cave is managed and cave dynamics
BMO Capital Markets 2011 Global Metals & Mining Conference
45
Indicative Costs Capital
The capital and operating costs shown are relative and provide an indication of the spread. Both green field and brown field projects are included as are operations where access is via shaft or by decline. They were developed simply by normalising to lowest cost producers in of capital and operating cost.
Operating
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
46
How Soon do you Get your Money Back?
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
47
Realising Value New generation of Cave Mines • • •
represent a step change in the size of operations require investment levels of $2 to 10 billion and require significant time to achieve operating targets
There are value drivers common to any mining project: 1. Costs (capital and operating) 2. Revenue 3. Time 1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
48
Investment in technology and innovation to drive value Cave dynamics • Block caving is inflexible and value locked in at the design phase • Important to understand cave behaviour and reliably forecast metal production (tons and grade)
Mine of the Future™
1 March 2011
Intelligent Mining • Autonomous equipment • Block cave operations well suited to concept of intelligent mining; real time information • Operating efficiencies
BMO Capital Markets 2011 Global Metals & Mining Conference
49
Investment in technology and innovation to drive value Rapid development • Tunnelling concepts that are more productive and cost effective than traditional methods • Integrated shaft boring machinery with the potential to dramatically improve safety while reducing construction time Optimised design and management • Building on ability to predict cave behaviour • Improved planning techniques and software to improve grade sequencing
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
50
The Vision – an Ore Factory Required Fragmentator
In Situ Crushing and Grinding
Fragment Size
Energy (Distance Traveled) Reliable Ore Flow Predictable Fragmentation (+ grade)
Ore Transport and Sizing
The The Ore RockFactory Factory
1 March 2011
BMO Capital Markets 2011 Global Metals & Mining Conference
51
Thank You Allan Moss, General manager Rio Tinto Copper Projects
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