1. Geology and Cu-Ni-PGE mineralization in
the South Kawishiwi Intrusion, Duluth
Complex, Minnesota
Dean M. Peterson
Senior Vice President, Exploration
2. May 5, 2009
2
Forward Looking Statement
No regulatory authority has approved or disapproved the information contained in
this presentation. This presentation includes certain statements that may be
deemed “forward looking statements”. All statements in this presentation, other
than statement of historical facts, that address future production, reserve potential,
exploration drilling, exploitation activities and events or developments that the
Company expects are forward-looking statements. Although the Company believes
the expectations expressed in such forward-looking statements are based on
reasonable assumptions, statements are not guarantees of future performance and
actual results or developments may differ materially from the forward-looking
statements. Factors that could cause actual results to differ materially form those in
the forward-looking statements include market prices, exploitation and exploration
successes, continued availability of capital and financing, general economic, market
or business conditions. Investors should be cautious that any such statements are
not guarantees of future performance and that actual results or developments may
differ materially from those projected in the forward-looking statements. The
company does not undertake to update or revise any forward-looking statements,
whether as a result of new information, future events or otherwise, save and except
as may be required by applicable securities laws.
No regulatory authority has approved or disapproved the information contained in this presentation.
This presentation includes certain statements that may be deemed “forward looking statements”. All
statements in this presentation, other than statement of historical facts, that address future production,
reserve potential, exploration drilling, exploitation activities and events or developments that the
Company expects are forward-looking statements. Although the Company believes the expectations
expressed in such forward-looking statements are based on reasonable assumptions, statements are
not guarantees of future performance and actual results or developments may differ materially from
the forward-looking statements. Factors that could cause actual results to differ materially form those
in the forward-looking statements include market prices, exploitation and exploration successes,
continued availability of capital and financing, general economic, market or business conditions.
Investors should be cautious that any such statements are not guarantees of future performance and
that actual results or developments may differ materially from those projected in the forward-looking
statements. The company does not undertake to update or revise any forward-looking statements,
whether as a result of new information, future events or otherwise, save and except as may be
required by applicable securities laws.
3. Outline
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• Regional Geology
• South Kawishiwi Intrusion
• Crystal-rich Slurries
• Thinking Outside the Gossan
• Details on the Maturi Cu-Ni-PGE Deposit
6. Mineral System Approach
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The mineral system approach to exploration attempts to
understand ore deposits as the final expression of multi-scale
systems encompassing the Earth that focus mass and
transfer energy to ultimately form ore deposits.
This approach to mineral exploration leads to systematic, scale-
dependent targeting models and allows for the recognition of
the largest-scale footprints of ore-forming systems.
9. The Reason Why is Physical Process?
Mantle melts become
sulfur-saturated when
they first encounter
bedded rocks in their
140 km rise from the
mantle, the sulfidic
Virginia Fm.
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Sulfide-bearing crystal-rich magmas intrude upwards
Sulfide-free crystal-bearing magmas intrude upwards
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12. Exotic Inclusions in the NLM
It is physically impossible for the NLM to carry
very large, high density exotic xenoliths from
great depths to their present position at troctolite
liquid viscosities. The magma must have been
more viscous (ie., a crystal-liquid slurry)
Nonmagnetic Basalt
Biwabik Iron Fm.
1212
13. Regional Magmatic Flow Model
1. Magma ascends through a mantle feeder dike
2. Sulfide saturation occurs while magma incorporates
sedimentary rocks (Virginia Fm sulfidic argillites)
3. Rift-parallel faulting opens a sub-horizontal space (NLM)
that magma traverses to the SW along
4. Subhorizontal sill intersects an active
transform fault and magma sills out (to
NNW) to form the Spruce Road Deposit
5. Continued flow lifts the hangingwall
Anorthosite as sill-like magma fingers
traverse to the WSW
6. Much Later – The Bald Eagle Intrusion
intrudes in a “Trap Door” fashion structurally
higher than the SKI
Idealized Magma Flow Model
Figures from Peterson, 2008
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15. A Fundamental Tenet: Describing Rocks
DESCRIPTION OF MAP
UNITS
We attempt to interpret the
magmatic history and
processes that formed the
mafic intrusions of the
Duluth Complex
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16. Initial Conditions
• The most critical part of analyzing and understanding
magmatic processes involves a clear and concise knowledge
of the nature of the system at the outset: when it all began !!
• The initial magmatic conditions that we think about include:
The geometry of the system;
The composition and initial state of crystallinity of the
magma;
The sequence of emplacement of the magma; and
The location of channelized magma flow and its resultant
variable ores.
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17. Initial Conditions, SKI
• What was the initial geometry of SKI magmas?
– Granitoid and/or locally sedimentary footwall
– Anorthosite hangingwall
– Sill-like bodies that intruded horizontally via the NLM
• What were the initial conditions of the magma?
– Troctolitic composition silicate melts (essentially Basalt)
– Phenocrysts of olivine and plagioclase (a crystal-liquid slurry)
– Initially sulfur super-saturated melts
• Therefore, contained sulfide droplets
• Sulfide droplets enriched in metals
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25. Cross Section Interpretations
We must go back to the
INITIAL CONDITIONS of the system.
The magma intruded as a sub-horizontal sill
Therefore one must rotate sections back ~24
o
to the horizontal!
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26. Now We Can Interpret The Facts
… and understand magma channelization and its effects on
ore types and their associated grades & tonnages
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30. The 2013 Maturi Stratigraphy & Model
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The goal is to best model the
Maturi Deposit based on all
available geological evidence.
The goal is to best model the
Maturi Deposit based on all
available geological evidence.
33. Mineralogical Control on Ores
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There clearly are Geometallurgical implications of the new Geological Model
Stage 3 Mineralized Zones Stage 2 Mineralized Zones
45. 45
The Duluth Metals Success Story
We had an intuitive geologic thought in 2006
east of the Maturi gossan and it seems to have
some legs via our recent resource estimate….
We had an intuitive geologic thought in 2006
east of the Maturi gossan and it seems to have
some legs via our recent resource estimate….
