MESABI TRUST

DURATION OF THE TRUST ESTATE

The largest component of the Trust Estate is the Peters Lease Lands. The Peters Lease provides that the leasehold estate thereunder will continue until the reserves of iron ore, taconite and other minerals or materials on the land subject to the Peters Lease are exhausted. The Amended Assignment of Peters Lease terminates when the Peters Lease terminates. The Cloquet Lease, executed in 1916, provides that the leasehold estate thereunder will continue until the reserves of iron ore, taconite and other minerals or materials on the land subject to the Cloquet Lease are exhausted. The Amended Assignment of Cloquet Lease terminates when the Cloquet Lease terminates. If Northshore decides to terminate or surrender either the Amended Assignment of Peters Lease or the Amended Assignment of Cloquet Lease, or both of them, it must first give Mesabi Trust at least six months’ notice of its intention to do so and, at Mesabi Trust’s request, reassign all of such leasehold interests to Mesabi Trust. If any such reassignment occurs, Northshore must transfer the leasehold interests to Mesabi Trust free and clear of liens, except public highways. In return, Mesabi Trust must assume Northshore’s future obligations as lessee under the reassigned leases. Upon termination of the lease under either the Amended Assignment of Peters Lease or the Amended Assignment of Cloquet Lease, or both of them, Northshore is obligated to remove within 90 days all engines, tools, machinery, railroad tracks and structures erected or placed by it, or under its direction, on the lands but may not remove or impair any supports placed in the mines, nor any timber or frameworks necessary to the use and maintenance of the shafts or other approaches to the mine.

The Peters Lease Lands and the Cloquet Lease Lands are located at the northeastern end of the Mesabi Iron Range and contain mineral deposits consisting of a highly metamorphosed sedimentary bed of banded magnetite in siliceous gangue, a form of low-grade iron ore known as taconite, approximately three tons of which must be beneficiated to produce one ton of high-grade pellets. The Mesabi Lease Lands contain substantially no commercial ore deposits and have been used principally in connection with mining the taconite from other parts of the Trust Estate, such as the provision of an area for location of service roads, supporting plants and equipment and dump sites for overburden.

Because the Trust is not involved with the mining operations at Northshore, the Trust relies on the ore reserve estimates reported by Cliffs’ in its Form 10-K (and related reports) filed with the SEC each year. In Cliffs’ Current Report on Form 8-K, Exhibit 96.3 (filed February 11, 2022) and as amended in Cliffs’ Form 10-K as of December 31, 2025 (filed February 9, 2026), the following information was provided by Cliffs regarding the estimated ore reserves at Northshore.

Iron Ore Mineral Reserves

As of December 31, 2025

(In Millions of Long Tons)

As disclosed in Cliffs’ Annual Report, 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 qualified person (within the meaning of Item 1300 of Regulation S-K), 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 life-of-mine 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. Cliffs disclosed that it evaluates and analyzes, and engages qualified persons to review and verify mineral reserves in accordance with its mineral policy and SEC requirements, and then completes updated life-of-mine plans. Cliffs last updated the Northshore life-of-mine plan in 2020.

As Cliffs disclosed in Cliffs’ Annual Report, mineral reserves estimates for its 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. The Trustees typically visit and inspect the open pits and mining and processing operations of Northshore in the fall each year. All of Cliffs’ mineral reserve estimates as of December 31, 2021 were reviewed and validated by its qualified person, SLR International Corporation, Lakewood, Colorado. The Technical Report Summary on the Northshore property was filed as Exhibit 96.3 to Cliffs’ Current Report on Form 8-K (filed February 11, 2022).