Item 2. Properties
ITEM 2. PROPERTIES
The following map shows the locations of our active operations and corporate headquarters as of December 31, 2025:
CORPORATE OFFICES
We lease our corporate headquarters in Cleveland, Ohio. We also have leased office space in West Chester, Ohio and Detroit, Michigan. We own office space located in Burns Harbor, Indiana and our Research and Innovation Center located in Middletown, Ohio.
STEELMAKING
Location Raw Material
(Tons in millions) State /Province Iron Ore Capacity (lt) 1
HBI Capacity (mt) Coke Capacity (nt) Coal Capacity (nt) Scrap Capacity (mt)
Hibbing 2
MN l 2.3
Minorca 3
MN l
Northshore MN l 5.2
Tilden MI l 7.5
United MN l 5.1
Toledo HBI OH l 1.9
Burns Harbor (Coke) IN l 1.8
Hamilton (Coke) ON l 0.7
Lake Erie (Coke) ON l 0.7
Monessen PA l 0.3
Warren OH l 0.5
Princeton WV l 1.8
FPT Multiple l N/A
1 As of December 31, 2025
2 Shown at 85.3% ownership share. During 2025, due to market conditions, we made the decision to partially idle our Hibbing mine. Our Hibbing mine remained partially idled as of December 31, 2025, but has an annual operational capacity of 4.6 million long tons when fully operational.
3 During 2025, due to market conditions, we made the decision to indefinitely idle our Minorca mine. Our Minorca mine remained idled as of December 31, 2025, but has an annual operational capacity of 2.8 million long tons.
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Location Raw Steel Processing and Finishing
(Tons in millions) State / Province BF-BOF EAF Configured Capacity (nt) 1
Hot-Rolled Cold-Rolled Coated Stainless & Electrical Plate Slab & Other
Burns Harbor IN l 5.1 l l l l
Burns Harbor Plate IN l
Butler PA l 0.3 l
Cleveland OH l 3.5 l l l l
Coatesville PA l 0.2 l l
Columbus OH l
Coshocton OH l
Dearborn 2
MI l l l l
Gary Plate IN l
Hamilton ON l l l
Indiana Harbor IN l 5.2 l l l l
Lake Erie ON l 2.5 l
Mansfield OH l 0.5 l
Middletown OH l 2.7 l l l l l
New Carlisle IN l l
Piedmont NC l
Rockport IN l l l
Zanesville OH l
1 As of December 31, 2025
2 During 2025, due to market conditions, we made the decision to idle our blast furnace, BOF steel shop, and continuous casting facilities at our Dearborn facility. This portion of our Dearborn facility remained idled as of December 31, 2025, but has annual raw steel capacity of 3.0 million net tons when fully operational.
STEELMAKING AND FINISHING FACILITIES
Our primary steel producing and finishing facilities are located across Indiana, Michigan, Ohio, Pennsylvania and Ontario. We operate seven blast furnaces and four EAFs, excluding any currently idled or permanently closed facilities. Finishing is completed on site at our integrated operations or at one of our 9 stand-alone processing and finishing facilities. As of December 31, 2025 and 2024, our annual configured production capacity of raw steel was approximately 20.0 million and 23.0 million net tons, respectively. During the years ended December 31, 2025 and 2024, our steelmaking facilities produced a total of 18.8 million and 17.7 million net tons of raw steel, respectively.
SCRAP PROCESSING FACILITIES
Our scrap business consists of our subsidiary FPT, which has 21 locations in Illinois, Michigan, Mississippi, Ohio, Tennessee and Ontario. These facilities are primarily located in Michigan and Ohio, which are in close proximity to our scrap consuming steel facilities. During each of the years ended December 31, 2025 and 2024, FPT processed approximately 3 million net tons of scrap metal, of which approximately 50% of total output was prime grade.
DIRECT REDUCTION PLANT
Our direct reduction plant is located in Toledo, Ohio, is near an existing dock, and has access to rail and heavy haul roads for operation logistics. We are leasing the property on which the plant is located. This plant produces a specialized high quality iron alternative to scrap and pig iron and has annual capacity of 1.9 million metric tons of HBI. During each of the years ended December 31, 2025 and 2024, our direct reduction plant produced a total of 1.6 million metric tons of HBI.
IRON ORE MINES AND PELLET PLANTS
The following information concerning our mining properties has been prepared in accordance with the requirements of subpart 1300 of Regulation S-K.
As used in this Annual Report on Form 10-K, the terms “mineral resource,” “measured mineral resource,” “indicated mineral resource,” “inferred mineral resource,” “mineral reserve,” “proven mineral reserve,” and “probable mineral reserve” are defined and used in accordance with subpart 1300 of Regulation S-K. Under subpart 1300 of Regulation S-K, mineral resources may not be classified as “mineral reserves” unless the determination has been made by a QP that the mineral resources can be the basis of an economically viable project. Investors are specifically cautioned not to assume that any part or all of the mineral deposits (including any mineral resources) in these categories will ever be converted into mineral reserves, as defined by the SEC.
Investors are cautioned that, except for that portion of mineral resources classified as mineral reserves, mineral resources do not have demonstrated economic value. Estimates of inferred mineral resources have too high of a degree of uncertainty as to their existence and may not be converted to a mineral reserve. Therefore, investors are cautioned not to assume that all or any part of an inferred mineral resource exists, that it can be the basis of an economically viable project, or that it will ever be upgraded to a higher category. Likewise, investors are cautioned not to assume that all or any part of measured or indicated mineral resources will ever be converted to mineral reserves.
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See Part I – Item 1A. Risk Factors – V. Sustainability and Development Risks – We rely on estimates of our recoverable mineral reserves, which are complex due to geological characteristics of the properties and the number of assumptions made .
As of December 31, 2025, our individually material mining properties, as determined in accordance with subpart 1300 of Regulation S-K, are the following iron ore mining properties: Northshore, Tilden and United.
The following summarizes certain information regarding our iron ore mining properties. The information relating to the Northshore, Tilden and United properties is derived, for the most part, from the technical report summaries relating to such properties prepared in compliance with Item 601(b)(96) and subpart 1300 of Regulation S-K. Portions of the following information are based on assumptions, qualifications and procedures that are not fully described herein. Reference should be made to the full text of the Technical Report Summaries, which are filed as Exhibits 96.1 through 96.3 to this Annual Report on Form 10-K and are incorporated by reference herein.
All of our iron ore mining operations are open-pit mines. Additional development is underway as required by long-range mine plans. Drilling programs are conducted periodically to collect geologic modeling data and for refining ongoing operations.
Geologic models are developed for all mines to define the major ore and waste rock types. Computerized block models for iron ore are constructed that include all relevant geologic and metallurgical data. These are used to generate grade and tonnage estimates, followed by detailed mine design and LoM plan operating schedules.
We currently own or co-own and operate five production-stage iron ore mines in Michigan and Minnesota. While our Tilden, Northshore and United mines were fully operational, as of December 31, 2025 our Minorca mine and a portion of our Hibbing mine were indefinitely idled. As of December 31, 2025, we had an aggregate annual production capacity of approximately 20.1 million long tons of iron ore pellets, including our 85.3% share of the Hibbing mine production. Our iron ore mines produce from deposits located within the Biwabik and Negaunee Iron Formation, which are classified as Lake Superior type iron formations that formed under similar sedimentary conditions in shallow marine basins approximately two billion years ago. Magnetite and hematite are the predominant iron oxide ore minerals present, with lesser amounts of goethite and limonite. Quartz is the predominant waste mineral present, with lesser amounts of other chiefly iron bearing silicate and carbonate minerals. The ore minerals liberate from the waste minerals upon fine grinding.
The following represents iron ore production for the last three fiscal years:
Iron Ore Production
(In millions of long tons) 2025 2024 2023
Hibbing 1,2
2 5 6
Minorca 2
1 3 3
Northshore 3 4 3
Tilden 6 7 8
United 5 5 5
Total 17 24 25
1 Hibbing is reported at 85.3% based on our ownership level.
2 In the first half of 2025, we indefinitely idled the Minorca mine and partially idled the Hibbing mine in order to consume excess pellet inventory produced in 2024. Both remained idled as of December 31, 2025.
All the infrastructure necessary to mine and process significant commercial quantities of iron ore is currently in place at all of our mine locations. Infrastructure items include high voltage electrical supplies, natural gas pipelines that connect to the North American distribution system, water sources, paved roads and highways, railroads for transporting crude ore and finished products, port facilities that connect to the Great Lakes, and accommodations for employees. Local and state infrastructure also includes hospitals, schools, airports, equipment suppliers, fuel suppliers, commercial laboratories and communication systems. Labor is readily available with major population centers within 25 miles of all of our properties.
All of our iron ore mining operations grant leases, licenses and easements for various purposes, including miscellaneous community land uses, utility infrastructure and other third-party uses, that encumber our properties but do not materially inhibit operations. Certain assets also serve as collateral securing obligations under our ABL Facility. We maintain the requisite state and federal permits and are in material compliance with all material permits.
The following provides an overview of our individually material iron ore properties:
NORTHSHORE
Northshore's (100% owned) mine is located on the northeastern edge of the Mesabi Iron Range in northeastern Minnesota, approximately four miles southeast of Babbitt, Minnesota at latitude 47°40'12.15"N and longitude 91°53'1.28"W. The processing facility is approximately 41 miles to the southeast and immediately adjacent to the city of Silver Bay in Lake County, Minnesota at latitude 47°17'38.95"N and longitude 91°15'23.38"W.
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Operations commenced in 1952 as an asset of the Reserve Mining Company and continued production until 1986 when Reserve Mining declared bankruptcy. Cyprus Minerals Company purchased the facilities in 1989. Cyprus subsequently sold the facilities to Cliffs in 1994.
Northshore holds 28,041 acres of surface rights, of which 8,966 acres are associated with mineral leases. 100% of the mineral rights are leased. The property is comprised of 10,356 acres of mineral leases. Some leases do not expire until the mineral reserves are exhausted while others expire between 2034 and 2075. Leases are maintained by making minimum prepaid royalty payments. Mining leases routinely are renegotiated and renewed as they approach their respective expiration dates.
The operation includes an open pit truck and shovel mine where two stages of crushing occur before the ore is transported along a wholly owned 47-mile rail line to the plant site in Silver Bay. At the plant site, two additional stages of crushing occur before the ore is sent to the concentrator. The concentrator utilizes rod mills and magnetic separation to produce a magnetite concentrate, which is delivered to the pellet plant located on-site. The plant can produce both standard and direct reduction-grade pellets. The plant site has its own ship loading port located on Lake Superior.
The net book value of Northshore's property, plant and equipment was $211 million as of December 31, 2025.
For further information, see Exhibit 96.1, Technical Report Summary on the Northshore Property, Minnesota, USA, prepared for the Company by the QP, SLR, with an effective date of December 31, 2021.
TILDEN
Tilden (100% owned) is located in Marquette County in Michigan’s Upper Peninsula, on the Marquette Iron Range, approximately five miles south of the city of Ishpeming, Michigan at latitude 46° 29' N and longitude 87° 40' W.
The property commenced operations in 1974 under a partnership of Algoma Steel, Stelco, J&L Steel, Wheeling-Pittsburgh Steel, Sharon Steel and The Cleveland-Cliffs Iron Company. The property has since been at least partially in the possession of a subsidiary of Cliffs. In 2001, Cliffs acquired Algoma Steel's 45% interest in Tilden. In 2017, Cliffs became the sole owner of Tilden.
Tilden holds 21,100 acres of surface rights and leases 2,470 acres of mineral rights expiring between 2061 and 2070. Leases are maintained by making minimum prepaid royalty payments. Mining leases routinely are renegotiated and renewed as they approach their respective expiration dates.
Operations include an open pit truck and shovel mine, a concentrator that utilizes single stage crushing, autogenous grinding mills and floatation to produce hematite concentrates that are then supplied to the on-site pellet plant. From the site, pellets are transported by our LS&I (Lake Superior & Ishpeming Railroad Company) rail to a ship loading port at Marquette, Michigan, operated by LS&I.
The net book value of Tilden's property, plant and equipment was $256 million as of December 31, 2025.
For further information, see Exhibit 96.2, Technical Report Summary on the Tilden Property, Michigan, USA, prepared for the Company by the QP, SLR, with an effective date of December 31, 2021.
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UNITED
United’s (100% owned) mine and offices are located on Minnesota's Mesabi Iron Range just north of Eveleth, Minnesota at latitude 47°29'1.62" N, longitude 92°32'23.69" W. The processing facilities are located approximately eight miles to the southeast.
The property commenced operations as an asset of Eveleth Taconite Company in 1965 before it was purchased by United (70% Cliffs and 30% Laiwu Steel) in December 2003. The property has been a wholly owned subsidiary of Cliffs since 2008.
United owns 14,199 acres of surface rights, of which 703 acres are associated with mineral leases. An additional 145 acres of surface rights are leased from the State of Minnesota. We lease 100% of the mineral rights, comprised of 4,908 acres expiring between 2037 and 2066, with the exception of the State of Minnesota mineral lease, which expires in 2027. Leases are maintained by making minimum prepaid royalty payments. Mining leases routinely are renegotiated and renewed as they approach their respective expiration dates.
Operations include an open pit truck and shovel mine where two stages of crushing occur before the ore is transported by rail, operated by CN, to the plant site. At the plant site an additional stage of crushing occurs before the ore is sent to the concentrator. The concentrator utilizes rod mills and magnetic separation to produce a magnetite concentrate, which is delivered to the on-site pellet plant. From the plant site, pellets are transported by CN rail to a ship loading port at Duluth, Minnesota, operated by CN.
The net book value of United’s property, plant and equipment was $554 million as of December 31, 2025.
For further information, see Exhibit 96.3, Technical Report Summary on the United Property, Minnesota, USA, prepared for the Company by the QP, SLR, with an effective date of December 31, 2021.
MINERAL RESOURCES
Mineral resources are defined under Item 1300 of Regulation S-K as a concentration or occurrence of material of economic interest in or on the Earth’s crust in such form, grade or quality, and quantity that there are reasonable prospects for economic extraction. A mineral resource is a reasonable estimate of mineralization, taking into account relevant factors such as cut-off grade, likely mining dimensions, location or continuity that, with the assumed justifiable technical and economic conditions, is likely to, in whole or part, become economically extractable.
A detailed breakdown of the mineral resources exclusive of mineral reserves is presented in the table below. Mineral resources were defined and constrained within open-pit shells, prepared by Cliffs, and based on a US$90.00/WLT pellet price for our Minnesota iron ore mines and on a US$100.00/WLT pellet price for our Michigan iron ore mine, freight-on-board (FOB) Lake Superior, while meeting defined cut-off grade criteria and existing pellet specifications. All estimates of mineral resource were reviewed and validated by the QP, SLR.
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The following represents iron ore mineral resources, exclusive of mineral reserves, as of December 31, 2025:
Iron Ore Mineral Resources
Measured Indicated Measured + Indicated Process Recovery Inferred
(In millions of long tons) Tonnage % Grade Tonnage % Grade Tonnage % Grade Tonnage % Grade
Total Iron Ore 1,351 22.5 1,452 23.2 2,803 22.8 31% 169 28.5
Michigan — — 104 33.2 104 33.2 35% 99 33.7
Minnesota 1,351 22.5 1,348 22.4 2,699 22.4 31% 70 21.0
Hibbing 1
8 19.2 1 18.7 9 19.2 25% — —
Minorca 484 22.9 317 22.9 801 22.9 33% 30 21.1
Northshore 767 22.1 391 22.4 1,158 22.2 26% 14 19.8
Tilden — — 104 33.2 104 33.2 35% 99 33.7
United 92 23.6 639 22.2 731 22.4 32% 26 21.5
1 Hibbing is reported at 85.3% based on our ownership level.
Reference point selected is the saleable tons based on the process recovery.
Process recovery may change based on the required saleable product mix and is reported as wet product percentage.
Mineral resources are estimated using the following cut-off grades: 13% magnetic Fe for Hibbing; 16% magnetic Fe for Minorca; 15% magnetic Fe for Northshore; 25% FeT for Tilden hematite; and 17% magnetic Fe for United.
Tonnage is reported in long tons equivalent to 2,240 pounds and has been rounded to the nearest 100,000.
For comparison purposes, the following represents iron ore mineral resources, exclusive of mineral reserves, as of December 31, 2024:
Iron Ore Mineral Resources
Measured Indicated Measured + Indicated Process Recovery Inferred
(In millions of long tons) Tonnage % Grade Tonnage % Grade Tonnage % Grade Tonnage % Grade
Total Iron Ore 1,351 22.5 1,483 23.6 2,834 23.1 31% 420 32.4
Michigan — — 135 35.5 135 35.5 36% 350 34.7
Minnesota 1,351 22.5 1,348 22.4 2,699 22.4 31% 70 21.0
Hibbing 1
8 19.2 1 18.7 9 19.2 25% — —
Minorca 484 22.9 317 22.9 801 22.9 33% 30 21.1
Northshore 767 22.1 391 22.4 1,158 22.2 26% 14 19.8
Tilden — — 135 35.5 135 35.5 36% 350 34.7
United 92 23.6 639 22.2 731 22.4 32% 26 21.5
1 Hibbing is reported at 85.3% based on our ownership level.
Reference point selected is the saleable tons based on the process recovery.
Process recovery may change based on the required saleable product mix and is reported as wet product percentage.
Mineral resources are estimated using the following cut-off grades: 13% magnetic Fe for Hibbing; 16% magnetic Fe for Minorca; 15% magnetic Fe for Northshore; 25% FeT for Tilden hematite; and 17% magnetic Fe for United.
Tonnage is reported in long tons equivalent to 2,240 pounds and has been rounded to the nearest 100,000.
Mineral resources decreased by 8.7% during 2025 primarily due to a reduction in inferred resources resulting from the Tilden LoM plan reserve analysis performed during 2025. The material assumptions and criteria used for the mineral resource estimates for Northshore, Tilden and United, including but not limited to leases, permits and geotechnical pit design, are covered in more detail in Sections 11 through 13 of the respective Technical Report Summaries filed as Exhibits 96.1 through 96.3 to this Annual Report on Form 10-K.
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MINERAL RESERVES
Mineral reserves are defined under Item 1300 of Regulation S-K as an estimate of tonnage and grade or quality of indicated and measured mineral resources that, in the opinion of the QP, can be the basis of an economically viable project. More specifically, it is the economically mineable part of a measured or indicated mineral resource, which includes diluting materials and allowances for losses that may occur when the material is mined or extracted.
Proven mineral reserves are defined under Item 1300 of Regulation S-K as the economically mineable part of a measured mineral resource and can only result from conversion of a measured mineral resource. Probable mineral reserves are defined under Item 1300 of Regulation S-K as the economically mineable part of an indicated and, in some cases, a measured mineral resource. All mineral reserves are classified as proven or probable and are supported by LoM plans.
Mineral reserves are based on pricing that does not exceed the three-year trailing average index price of iron pellets adjusted to realized price. We evaluate and analyze, and engage QPs to review and verify, mineral reserves in accordance with our mineral policy and SEC requirements and then complete LoM plan reserve analyses. The table below identifies the year in which the latest LoM plan reserve analysis was completed.
Mineral reserves estimates for our iron mines are constrained by fully designed open pits developed using three-dimensional modeling techniques. These open pits incorporate design slopes, practical mining shapes and access ramps to assure the accuracy of our mineral reserve estimates. All operations' mineral reserves have been adjusted net of production through year-end 2025. All mineral reserves estimates were reviewed and validated by the QP, SLR.
The following represents iron ore mineral reserves as of December 31, 2025. These estimates are periodically updated to reflect past iron ore production, updated mine plans, new exploration information, and other geologic or mining data. Mineral reserves were defined and constrained within open-pit shells, prepared by Cliffs, and based on a US$90.00/WLT pellet price for our Minnesota iron ore mines and on a US$100.00/WLT pellet price for our Michigan iron ore mine, freight-on-board (FOB) Lake Superior, while meeting defined cut-off grade criteria and existing pellet specifications. All estimates of mineral reserves were reviewed and validated by the QP, SLR.
Iron Ore Mineral Reserves
as of December 31, 2025
Last LoM Plan Proven Probable Proven & Probable Process
(In millions of long tons) Reserve Analysis Tonnage % Grade Tonnage % Grade Tonnage % Grade Recovery
Total Iron Ore 485 24.0 1,597 26.2 2,082 25.7 32%
Michigan 2 36.1 436 34.7 438 34.7 35%
Minnesota 483 24.0 1,161 23.0 1,644 23.3 31%
Hibbing 1
2024 58 19.3 4 19.0 62 19.3 24%
Minorca 2021 76 23.7 7 25.3 83 23.8 35%
Northshore 2020 264 25.3 519 24.1 783 24.5 29%
Tilden 2025 2 36.1 436 34.7 438 34.7 35%
United 2019 85 23.5 631 22.1 716 22.3 33%
1 Hibbing is reported at 85.3% based on our ownership level.
Reference point selected by the QP is the saleable tons based on the process recovery.
Process recovery may change based on the required saleable product mix and is reported as wet product percentage.
Mineral reserves are estimated using the following cut-off grades: 13% magnetic Fe for Hibbing; 16% magnetic Fe for Minorca; 19% magnetic Fe for Northshore; 25% FeT for Tilden hematite; and 17% magnetic Fe for United.
Tonnage is reported in long tons equivalent to 2,240 pounds and has been rounded to the nearest 100,000.
Mineral reserves are classified as probable if not scheduled within the first 20 years.
The material assumptions and criteria used for the mineral reserves estimates for Northshore, Tilden and United, including but not limited to leases, permits and geotechnical pit design, are covered in more detail in Sections 11 through 13 of the respective Technical Report Summaries filed as Exhibits 96.1 through 96.3 to this Annual Report on Form 10-K.
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For comparison purposes, the following represents iron ore mineral reserves as of December 31, 2024:
Iron Ore Mineral Reserves
as of December 31, 2024
Proven Probable Proven & Probable Process
(In millions of long tons) Tonnage % Grade Tonnage % Grade Tonnage % Grade Recovery
Total Iron Ore 522 23.8 1,619 26.3 2,141 25.7 32%
Michigan 4 35.3 458 34.6 462 34.6 37%
Minnesota 518 23.8 1,161 23.0 1,679 23.3 31%
Hibbing 1
67 19.0 4 19.0 71 19.0 24%
Minorca 78 23.7 7 25.3 85 23.8 35%
Northshore 275 25.3 519 24.1 794 24.5 29%
Tilden 4 35.3 458 34.6 462 34.6 37%
United 98 23.4 631 22.1 729 22.3 33%
1 Hibbing is reported at 85.3% based on our ownership level.
Reference point selected by the QP is the saleable tons based on the process recovery.
Process recovery may change based on the required saleable product mix and is reported as wet product percentage.
Mineral reserves are estimated using the following cut-off grades: 13% magnetic Fe for Hibbing, 16% magnetic Fe for Minorca; 19% magnetic Fe for Northshore; 25% FeT for Tilden hematite; and 17% magnetic Fe for United.
Tonnage is reported in long tons equivalent to 2,240 pounds and has been rounded to the nearest 100,000.
Mineral Reserves are classified as probable if not scheduled within the first 20 years.
Overall, mineral reserves estimates as of December 31, 2025, as compared to the prior-year period, decreased by 2%, which was driven by mining depletion.
INTERNAL CONTROLS DISCLOSURE
Each material iron ore mine operated by the Company has demonstrated repeated attainment of annual production and quality targets for over 50 years. Internal controls the Company uses in its industry-standard approach to exploration and mineral resource and reserve estimation efforts are governed by its Mineral Reserve and Mineral Resource Estimation Policy and are detailed in Cliffs’ minimum operating standards for Resource Estimation and Strategic Mine Planning. The controls include: confirmation of drill collar locations and drill hole traces, drill logging and sample collection and security, database verification and security, QA/QC programs, internal and third-party QP statistical analysis, third-party QP model validation, and reconciliation. Modeling and analysis of the Company’s resources has been developed by Company personnel or third-party consultant SLR and reviewed by internal management and the external independent QP, SLR. Reserve estimations have been completed by Company personnel and reviewed by internal management and the QP, SLR.
Drill hole collar surveying methods have evolved with advancements in technology, moving from optical methods to global positioning system, which is currently in use. For the deposit type, all survey methods used for the collar locations are expected to provide adequate accuracy for the drill hole locations. Due to the relatively shallow depth and vertical nature of drill holes at Cliffs’ Minnesota mining operations, downhole deviation surveys are typically not conducted. Drill holes pierce the generally shallow-dipping, tabular iron formation at near perpendicular angles. At the more geologically and structurally complex Tilden mine in Michigan, where drilling deeper than 500 feet is required, downhole surveys have moved from a clay-impression procedure to the gyroscopic method currently in use.
Drill core is transported directly from the drill rig to each site’s core logging facility by either the drilling contractor or Cliffs’ personnel. Temporary core storage is located at each site’s secure logging facility. Unused sample reserves, parts, concentrates and splits are securely stored in labeled boxes or barrels at a Cliffs laboratory facility or logging facility.
Cliffs' QA/QC programs are site-specific, well-developed protocols that involve formal procedures for the use of crude material standards developed from on-site material, as well as regularly inserted coarse and concentrate duplicate samples, control chart analysis and reporting. Cliffs typically uses internal and external labs for geometallurgical analyses that are accredited with ASQ/ANSI ISO-9001:2015 (American Society for Quality/American National Standards Institute) for their system of quality management. Quality sample results are monitored and enacted on where warranted. Also, Cliffs has implemented a drill campaign reporting practice to ensure results are documented, with defined and illustrated failure metrics, outcomes of investigations, comparisons with previous year’s results and recommendations. The QP, SLR, reviewed Cliffs' QA/QC practices and provided recommendations for further work. Where QA/QC programs were still in development at that time and prior to resource estimation, Cliffs conducted data verification studies utilizing a suite of blind crude ore standards and blind duplicates from historical sample reserves within the LoM plan. Where unaccredited labs provided data used in resource estimation, check lab studies were initiated to verify analytical results. Cliffs continues to work toward completing alignment of QA/QC protocols at each mine to the Company’s current best practice by formalizing procedures.
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Cliffs maintains exploration drill hole data in an externally-managed, access-controlled acQuire database that is backed up online at regularly scheduled intervals to provide data redundancy and security. Certification of database integrity is accomplished by both visual and statistical inspections comparing geology, assay values and survey locations cross-referenced back to laboratory data and geologic logs. Any discrepancies identified are corrected by referring to hard-copy assay and core log information archived in Cliffs' Mine Engineering department files. Prior to modeling, a secondary validation check is completed using built-in data validation routines in the modeling software.
Cliffs performs routine drill hole database verification with every new drilling program and new block model build, including: check of unique drill hole identifications and collar coordinates; check of assay or lithology points extending past the specified maximum depth of drill hole; check of abnormal dips and azimuths of downhole drill hole surveys; check of negative, overlapping and missing intervals; and check of incorrect lithologic codes and assay values.
In 2020 and 2021, Cliffs' geologists completed data verification exercises within the LoM plan area for each mining operation. This was audited by the QP, SLR, to assess accuracy and completeness. Database values were checked against source documents including collar surveys, geologic logs and assay certificates. Data verification included collar coordinates, depth intervals of geologic units and assay samples, and results of geometallurgical analyses applied to mineral resource estimation and mine planning.
Cliffs’ mineral resource estimates were validated by the QP, SLR, using standard industry techniques including statistical comparisons with composite samples and parallel nearest neighbor estimates, swath plots, as well as visual reviews in cross-section and plan. A visual review comparing blocks to drill holes for key economic variables, completed after the block modeling work, was performed to ensure general lithologic and analytical conformance. Cliffs’ mining operations have demonstrated good agreement between planned and actual product produced over more than 45 years for each operation.
Cliffs classifies the mineral resources based primarily on drill hole spacing and influenced by geologic continuity, ranges of economic criteria and reconciliation. Some post-processing is undertaken to ensure spatial consistency and remove isolated and fringe blocks. The resource area for each operation is limited by a polygon and subsequent pit shell based on practical mining limits. To ensure that all mineral resource statements satisfy the “reasonable prospects for economic extraction” requirement, in the definition of the mineral resources under Item 1300 of Regulation S-K, factors significant to technical feasibility and potential economic viability are considered (e.g., ability to obtain permits and legal and land tenure considerations). Mineral resources are defined and constrained within optimized, open-pit shells, prepared by Cliffs and reviewed by the QP, SLR, and based on a US$90.00/WLT pellet value and target pellet iron content.
Grade and tonnage reconciliations are run on current production versus modeled production, which provides insight on the accuracy of the modeled assay data versus actual production for each mining operation.
For a discussion of comprehensive risk inherent in the estimation of mineral reserves, see Part I - Item 1A. Risk Factors - V. Sustainability and Development Risks - We rely on estimates of our recoverable mineral reserves, which are complex due to geological characteristics of the properties and the number of assumptions made.
COAL MINING AND COKEMAKING
Princeton is a coal mining complex located in West Virginia that specializes in surface and underground mining of metallurgical coal to produce coke and pulverized coal injection coal. As of December 31, 2025, we have annual rated metallurgical coal production capacity of 1.8 million net tons from our Princeton mine. During the years ended December 31, 2025 and 2024, the mine produced 1.2 million and 1.0 million net tons of coal, respectively. We own 100% of the Princeton mine, which has been operating since 1995. We own 49% of the mineral rights and lease 51% via multiple mineral leases having varying expiration dates. Mining leases are routinely renegotiated and renewed as they approach their respective expiration dates. Princeton's operations consist of three open-pit surface mines, one underground mine, a preparation plant and two rail loadouts.
Our Monessen and Warren facilities produce furnace coke and related by-products in Monessen, Pennsylvania and Warren, Ohio, respectively. We also operate cokemaking facilities located within our Burns Harbor, Lake Erie and Hamilton locations. These facilities have an aggregate annual rated capacity of 4.0 million net tons. During the years ended December 31, 2025 and 2024, our cokemaking facilities produced 3.1 million and 2.4 million net tons of coke, respectively.
OTHER BUSINESSES
Our Tubular operating segment consists of plants in Walbridge, Ohio and Columbus, Indiana. The Walbridge plant operates six electric resistance welded tube mills and one laser re-cutting line on owned property. The Columbus plant operates five electric resistance welded tube mills, four high-speed cold saws, and one laser re-cutting line on leased property.
Our Tooling and Stamping operating segment provides advanced-engineered solutions, tool design and build, hot- and cold-stamped steel components and complex assemblies for the automotive market across 10 plants, of which certain of these are under long-term lease agreements, in Ontario, Alabama, Kentucky and Tennessee. Its facilities feature seven large-bed, hot-stamping presses, providing 13 lines of production; 60 cold-stamping presses ranging from 150 net tons to 3,000 net tons of pressing capacity; 18 large-bed, high-tonnage tryout presses with prove-out capabilities for new tool builds; and 173 multi-axis welding assembly cells.
Our European operating segment consists of a metal distribution company that buys and sells steel, steel products and other materials. We operate out of six different European countries: the Netherlands, Italy, Germany, France, Spain and the United Kingdom.
39 | CLF 2025 FORM 10-K
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