Ivanhoe Electric Announces Significant Resource Upgrade at the Santa Cruz Copper Project in Arizona, Including Resource Additions at the East Ridge and Texaco Deposits 65% Increase in Tonnage and 82% Increase in Total Contained
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February 14, 2023
Ivanhoe Electric Announces Significant Resource Upgrade at the
Santa Cruz Copper Project in Arizona, Including Resource Additions
at the East Ridge and Texaco Deposits
65% Increase in Tonnage and 82% Increase in Total Contained
Copper in Indicated Resources Across Exotic, Oxide and Enriched
Domains at Santa Cruz Deposit
Total Contained Copper in Indicated Resources Across all Deposits
and Domains Increases by 11%, with a Near-Doubling of the Copper
Cut-Off Grade to a Minimum of 0.70%
Initial Mineral Resource Declarations at East Ridge and Texaco
Deposits Confirm Expansion Potential of the Project Resource Base
Increased Resource Base Will Form the Foundation of Initial
Assessment Expected by the End of Q3 2023
Recent Metallurgical Testwork Confirms up to 94% Total Copper
Recovery with a Leach-Float Circuit is Achievable at the Santa Cruz
Deposit
Ivanhoe Electric to Host Investor Conference Call Today at 12pm ET
PHOENIX, ARIZONA – Ivanhoe Electric (NYSE American: IE; TSX: IE) Executive
Chairman, Robert Friedland and President and Chief Executive Officer, Taylor Melvin
are pleased to provide an updated Mineral Resource Estimate for the Santa Cruz Copper
Project (“Project”) located west of Casa Grande, Arizona.
The updated Mineral Resource Estimate now includes the first Mineral Resources
declared at the East Ridge Deposit directly adjacent to the Santa Cruz Deposit and at
the Texaco Deposit approximately one mile to the northeast.
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The updated Mineral Resource Estimate utilizes higher cut-off grades than the 0.39%
cut-off used in the December 8, 2021 Santa Cruz Project Mineral Resource statement.
The higher cut-off grades were used to account for the consistency and thickness of the
higher-grade exotic, oxide and enriched copper domains, which support a more
selective, lower-impact bulk mining method.
The resource at the Santa Cruz Deposit reflects a 0.70% total copper cut-off, while the
resources at East Ridge and Texaco reflect a 0.90% and 0.80% total copper cut-off,
respectively. Even at these higher cut-off grades, the overall project-wide contained
copper in Indicated Mineral Resources increased by 11%. Importantly, project-wide
contained copper in Indicated Mineral Resources, excluding primary sulfide
mineralization, increased by 86%.
Mr. Friedland commented: “We are making great strides towards our ambitious goal of
constructing a low-carbon footprint, underground copper mine with minimal surface
disturbance in Arizona. The maiden resource estimates for the East Ridge and Texaco
Deposits were founded on the knowledge gained from our 26.5 km2 (6,500-acre)
proprietary Typhoon™ 3D induced polarization and resistivity geophysical survey
conducted in 2022 and build on the success we have achieved at the Santa Cruz
Deposit. Today’s announcement is an important milestone that underpins the future
development potential of the Santa Cruz Copper Project.”
Mr. Melvin commented: “This resource update is the culmination of a tremendous effort
by our team at Santa Cruz. The drilling to date increases our confidence in the high
copper grades at the Santa Cruz Deposit and confirms the growth potential at the
nearby East Ridge and Texaco Deposits. The updated resource provides an excellent
foundation for our initial economic assessment, which we expect before the end of Q3
2023.”
Highlights of the Updated Santa Cruz Project Mineral Resource Estimate
Using a 0.70% copper cut-off grade, Indicated Mineral Resources at the Santa Cruz
Project total 226.7 million tonnes grading 1.24% total copper (2.8 million tonnes of
contained copper), and Inferred Resources total 149.0 million tonnes grading 1.24%
total copper (1.8 million tonnes of contained copper).
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Click to View Mineral Resource Video (https://vimeo.com/798541269/87ddccde9a)
Table 1: Updated Mineral Resource Estimate including the Santa Cruz, East
Ridge and Texaco Deposits, using a 0.70% copper cut-off at Santa Cruz, 0.90%
at East Ridge and 0.80% at Texaco (December 31, 2022 Mineral Resource
Estimate).
Category
Tonnage
(millions of
tonnes)
Total Copper
Grade
(%)
Total
Soluble
Copper Grade
(%)
Total
Contained
Copper
(millions of
tonnes)
Total
Contained
Soluble
Copper
(millions of
tonnes)
All Deposits: Indicated 226.7 1.24% 0.82% 2.8 1.9
All Deposits: Inferred 149.0 1.24% 0.82% 1.8 1.2
Refer to Notes on Mineral Resources following Table 5.
The Santa Cruz Deposit remains the largest deposit at the Santa Cruz Project with
Indicated Mineral Resources totaling 223.2 million tonnes grading 1.24% total copper
and Inferred Mineral Resources totaling 62.7 million tonnes grading 1.23% total copper.
Importantly, the Santa Cruz Deposit now includes 78% Indicated Resources at higher
average grades than the previous estimate, which will form the base for the upcoming
Initial Assessment/ Preliminary Economic Assessment ("Santa Cruz IA/PEA"). For
comparison, the December 8, 2021 Santa Cruz Mineral Resource Estimate had only 52%
classified as Indicated Mineral Resources at an average grade of 0.93% copper.
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Figure 1: Santa Cruz Project Updated Mineral Resource Estimate (December 31,
2022 Mineral Resource Estimate)
The initial East Ridge and Texaco Mineral Resource Estimates reflect limited portions of
the historically defined areas of mineralization and represent what Ivanhoe Electric has
delineated within the past six months. Both East Ridge and Texaco Deposits exhibit
significant potential for high-grade copper additions within the structural corridors that
control the mineralization. Project-wide, Ivanhoe Electric currently has six diamond drill
rigs active on site.
Table 2: Initial Mineral Resource Estimates for the East Ridge and Texaco
Deposits (December 31, 2022 Mineral Resource Estimate).
Category Deposit
Tonnage
(millions of
tonnes)
Total Copper
Grade
(%)
Total
Soluble
Copper
Grade
(%)
Total
Contained
Copper
(millions of
tonnes)
Total
Contained
Soluble
Copper
(millions of
tonnes)
Indicated Texaco1 3.6 1.33 0.97 0.05 0.03
Inferred
Texaco1 62.3 1.21 0.56 0.8 0.3
East Ridge2 24.0 1.36 1.26 0.3 0.3
1. Texaco Deposit cut-off grade is 0.80% total copper.
2. East Ridge Deposit cut-off grade is 0.90% total copper.
Refer to Notes on Mineral Resources following Table 5.
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The Updated Santa Cruz Project Mineral Resource Estimate is the Result of
a Highly Successful Drill Program
The primary focus of the ongoing drilling program at each of the Santa Cruz, East Ridge
and Texaco Deposits was to:
1. Target the higher-grade areas (greater than 1.2% copper) to confirm if the
December 8, 2021 Mineral Resource Estimate grade was as outlined in the
estimate.
2. Expand the higher-grade copper areas with a strong focus on the Exotic, Oxide
and Chalcocite domains.
3. Target the structural controls that influence the higher-grade copper domains.
4. Complete various “twin holes” in proximity to historical drilling which can be
compared (geologically, structurally, geochemically, etc.) to each other to
determine if significant geological and sampling bias exists.
5. Upgrade high-grade Inferred Mineral Resources into the Indicated category.
6. At East Ridge and Texaco, confirm the higher-grade historical intercepts and
determine if the higher-grade areas could be expanded.
Collectively, the Santa Cruz drill program delivered on all six of these points.
Ivanhoe Electric’s Infill Drill Program at the Santa Cruz Deposit
Successfully Expands the Higher-Grade and Leachable Exotic, Oxide and
Enriched Domains
With a specific focus on expanding the higher-grade areas of the Santa Cruz Deposit
(greater than 1.2% total copper within the Exotic, Oxide, and Chalcocite Enriched
domains), Ivanhoe Electric successfully improved the Indicated Resources tonnage in
these domains within the Santa Cruz Deposit by 65%. The average copper grade of
Indicated Resources in these domains at the Santa Cruz Deposit increased by 10%,
contributing to an 82% increase in contained copper metal. These important domains
host the high-grade soluble copper minerals that will be the central focus of the Santa
Cruz IA/PEA expected in Q3 2023.
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Figure 2: Santa Cruz Deposit Indicated Mineral Resource Estimate Comparison
between December 8, 2021 and December 31, 2022 within the Exotic, Oxide, and
Chalcocite Enriched Domains.
Comparison to the December 8, 2021 Santa Cruz Deposit Mineral Resource
Estimate
The updated Mineral Resource Estimate includes a higher copper cut-off grade of 0.70%
as the base case, reflective of a higher-grade, more-selective and lower-impact mining
method. This compares to the December 8, 2021 Mineral Resource Estimate which
applied a “bulk tonnage mining method” 0.39% copper cut-off grade as the base case.
When the updated Mineral Resource sensitivity is compared to the December 8, 2021
Mineral Resource Estimate using the same 0.39% copper cut-off grade, infill drilling at
the Santa Cruz Deposit has successfully added 46% more contained copper in the
Indicated category.
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Figure 3: Comparison between the December 8, 2021 and December 31, 2022
Mineral Resource Estimates for the Santa Cruz Deposit using the 2021 Cut-Off
Grade of 0.39% Total Copper.
Table 3: The December 8, 2021 Mineral Resource Estimate for the Santa Cruz
Deposit Compared to the December 31, 2022 Mineral Resource: Sensitivity at a
0.39% copper cut-off grade.
December 8, 2021
Mineral Resource Estimate
at 0.39% copper cut-off
December 31, 2022
Mineral Resource Sensitivity
at 0.39% copper cut-off
Category
Tonnage
(millions of
tonnes)
Total
Copper
Grade
(%)
Total
Contained
Copper
(millions of
tonnes)
Tonnage
(millions of
tonnes)
Total
Copper
Grade
(%)
Total
Contained
Copper
(millions of
tonnes)
Santa Cruz Deposit: Indicated 274.0 0.93% 2.5 392.5 0.94% 3.7
Santa Cruz Deposit: Inferred 248.8 0.91% 2.3 179.6 0.74% 1.3
Refer to Notes on Mineral Resources following Table 5.
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Increased Understanding of Distinct Mineralized Domains at Santa Cruz is Critical to
Unlocking the Deposit
• Exotic oxide mineralization (Exotic) is of more limited known occurrence and
tends to form very high-grade mineralization in paleo-valleys at the contact of the
mineralized bedrock and the overlying gravel cover. This mineralization formed in
basal gravels through the precipitation of copper that was transported in solution
by migrating groundwater. These zones have shown to contain spectacularly high-
grade copper.
• Supergene oxide mineralization (Oxide) forms the uppermost zone of
mineralization and is dominated by chrysocolla (a copper oxide that is 34% copper
by weight) and atacamite (a copper chloride that is 60% copper by weight).
• Supergene sulfide mineralization (Chalcocite Enriched) underlies the supergene
oxide zone and is comprised primarily of enriched chalcocite (a copper sulfide
that is 80% copper by weight), with accessory chalcopyrite and pyrite that is
partially or completely replaced by chalcocite.
• Hypogene sulfide mineralization (Primary) underlies the supergene sulfide zone
and consists of chalcopyrite (a copper sulfide that is 35% copper by weight),
pyrite, molybdenite, and minor bornite and covellite, hosted within porphyry-style
phyllic alteration. Intensity of mineralization is highest around Laramide-age dyke
intrusions that cut the mineralized Proterozoic-age Oracle Granite country rock.
Figure 4: Santa Cruz Deposit Mineralized Domains Shown at 0.70% Copper
Cut-Off Grade.