<PAGE>

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                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM 10-K

                  ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d)
                     OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended:                                  Commission File No.:
     JANUARY 31, 1999                                              1-4488


                              --------------------

                                  MESABI TRUST
             (Exact name of registrant as specified in its charter)

           NEW YORK                                              13-6022277
(State or other jurisdiction of                               (I.R.S. Employer
 incorporation or organization)                              Identification No.)

                           C/O BANKERS TRUST COMPANY
                        CORPORATE TRUST AND AGENCY GROUP
                                  P.O. BOX 318
                             CHURCH STREET STATION
                               NEW YORK, NEW YORK
                                   10008-0318
                    (Address of principal executive offices)

               Registrant's telephone number, including area code:
                                 (212) 250-6519

           Securities registered pursuant to Section 12(b) of the Act:
                  UNITS OF BENEFICIAL INTEREST IN MESABI TRUST
        Securities registered pursuant to Section 12(g) of the Act: NONE

         Indicate by check mark whether the Registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
Registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days.  YES /X/ NO / /

         Indicate by check mark if disclosure of delinquent filers pursuant to
Item 405 of Regulation S-K is not contained herein, and will not be contained,
to the best of Registrant's knowledge, in definitive proxy or information
statements incorporated by reference in Part III of this Form 10-K or any
amendment to this Form 10-K. /X/

         As of April 26, 1999, the aggregate market value of the Units of
Beneficial Interest held by non-affiliates of the registrant, based on the
closing price as reported on the New York Stock Exchange, aggregated
approximately $42,316,007*. As of April 26, 1999, 13,120,010 Units of
Beneficial Interest were outstanding.

------------------------
*        Includes approximately $49,075 representing the market value, as of
         April 26, 1999, of 15,100 Units the beneficial ownership of which is
         disclaimed by affiliates (see Item 12 herein).

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--------------------------------------------------------------------------------

<PAGE>

         Certain items in Parts I and II incorporate information by reference
from the Annual Report of the Trustees of Mesabi Trust to the Holders of
Certificates of Beneficial Interest for the fiscal year ended January 31, 1999,
which is annexed hereto and filed herewith as Exhibit 13.1.

                                     PART I

ITEM 1.  BUSINESS.

         (a) GENERAL DEVELOPMENT OF BUSINESS.

         The information under the headings "Mesabi Trust," "The Trust Estate,"
"Leasehold Royalties" and "Land Trust and Fee Royalties" set forth on pages 9
through 13 of the Annual Report of the Trustees of Mesabi Trust for the fiscal
year ended January 31, 1999 (the "Annual Report") is incorporated herein by
reference. Certain capitalized terms used below in this Part I are defined in
the Annual Report.

         Mesabi Trust ("Mesabi Trust" or the "Trust"), formed pursuant to an
Agreement of Trust dated July 18, 1961 (the "Agreement of Trust"), is a trust
organized under the laws of the State of New York. Mesabi Trust holds all of the
interests formerly owned by Mesabi Iron Company, including all right, title and
interest in the Amended Assignment of Peters Lease, the Amended Assignment of
Cloquet Lease, the beneficial interest in the Mesabi Land Trust and all other
assets and property identified in the Agreement of Trust. The Amended Assignment
of Peters Lease relates to an Indenture made as of April 30, 1915 among East
Mesaba Iron Company, Dunka River Iron Company and Claude W. Peters (the
"Peters Lease") and the Amended Assignment of Cloquet Lease relates to an
Indenture made May 1, 1916 between Cloquet Lumber Company and Claude W. Peters
(the "Cloquet Lease").

         The Trust will terminate twenty-one (21) years after the death of the
survivor of twenty-five (25) persons named in an exhibit to the Agreement of
Trust. The youngest person on this exhibit is now 38 years old.

         (b) FINANCIAL INFORMATION ABOUT INDUSTRY SEGMENTS.

         Substantially all of the Trust's revenue, operating profits and assets
relate to one business segment--iron ore mining.

         (c) NARRATIVE DESCRIPTION OF BUSINESS.

         The Agreement of Trust specifically prohibits the Trustees from
entering into or engaging in any business. This prohibition applies even to
business activities the Trustees deem necessary or proper for the conservation
and protection of the Trust Estate. Accordingly, the Trustees' activities in
connection with the administration of Trust assets are limited to collecting
income, paying expenses and liabilities, distributing net income and protecting
and conserving the assets held.

         Pursuant to a ruling from the Internal Revenue Service, which ruling
was based on the terms of the Agreement of Trust including the prohibition
against entering into any business, the Trust is not taxable as a corporation
for Federal income tax purposes. Instead, the holders of the Units of Beneficial
Interest (the "Unitholders") are considered as "owners" of the Trust and the
Trust's income is taxable directly to the Unitholders.

         Leasehold royalty income constitutes the principal source of the
Trust's revenue. Royalty rates are determined in accordance with the terms of
Mesabi Trust's leases and assignments of leases. Until

<PAGE>

August 17, 1989, the overriding royalty was based on the quantity and iron
content of pellets shipped by Reserve Mining Company ("Reserve") from Mesabi
Trust lands, although Mesabi Trust did not receive any royalty income from May
1986 until July 1990 because Reserve filed a Chapter 11 bankruptcy petition
and suspended its operations. On August 17, 1989, Cyprus Northshore Mining
Corporation ("Cyprus NMC") purchased substantially all of Reserve's assets,
including Reserve's interest in the Mesabi Trust lands. At the same time, Mesabi
Trust entered into certain agreements with Reserve's Chapter 11 Trustee and
Cyprus NMC (the "Amended Assignment Agreements"). The Amended Assignment
Agreements modified the method of calculating overriding royalties payable to
Mesabi Trust and transferred Reserve's interest in the Mesabi Trust lands to
Cyprus NMC. Pursuant to the Amended Assignment Agreements, overriding royalties
are determined by both the volume and selling price of iron ore products
shipped. In 1994, Cyprus NMC was sold by its parent corporation to
Cleveland-Cliffs Inc. ("CCI") and renamed Northshore Mining Corporation
("Northshore"). CCI now operates Northshore as a wholly-owned subsidiary.

         In its Annual Report for the year ended December 31, 1998 ("CCI's 
Annual Report"), CCI, parent company of Northshore, the lessee/operator of 
Mesabi Trust iron ore interests, stated that it is continuing to evaluate 
whether to build a facility to produce pig iron at CCI's Northshore Mine in 
Minnesota that would annually produce 700,000 metric tons of premium grade 
pig iron. In the same annual report, it was stated that good progress has 
been made in a number of areas on the project, but that a decision relative 
to proceeding with this project has been delayed by uncertainty about market 
conditions and timing of state environmental permitting. Because of the 
preliminary nature of this information, the Mesabi Trustees are unable to 
determine at this time how the addition of a pig iron facility (if the 
project proceeds) would impact overall revenues of Mesabi Trust. As indicated 
elsewhere in this report, the Trust's revenues are currently derived almost 
entirely from iron ore pellet production and sales.

         Mesabi Trust has no employees, but it engages independent consultants
to assist the Trustees in monitoring, among other things, the amount and sales
prices of minerals shipped by Northshore from Silver Bay, Minnesota. As noted
above, the information regarding amounts and sales prices of shipped minerals is
used to compute the royalties payable to Mesabi Trust by Northshore. Bankers
Trust Company, one of the Trustees, also performs certain administrative
functions for Mesabi Trust.

ITEM 2.  PROPERTIES.

         The information under the heading "The Trust Estate" set forth on page
9 of the Annual Report of the Trustees of Mesabi Trust for the fiscal year ended
January 31, 1999 is incorporated herein by reference.

         The Peters Lease provides that each leasehold estate 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 Mesabi Lease terminates when
the Peters Lease terminates. The Cloquet Lease, executed in 1916, terminates in
the year 2040. If Northshore decides to terminate or surrender one or more of
these leases, 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 leases
to Mesabi Trust. If any such reassignment occurs, Northshore must transfer the
lease 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.

         The Trustees have neither made nor caused to be made any surveys or
test drillings to ascertain the iron ore reserves on any land subject to the
Peters Lease or the Cloquet Lease. However, initial surveys and test drillings
made by Mesabi Iron Company many years ago indicated that these lands


                                       2
<PAGE>

contained accessible reserves of at least 1-1/2 billion tons of mineable raw 
material, capable of yielding approximately 500 million tons of concentrated 
product. In CCI's Annual Report, CCI estimated that there currently remains 
enough ore reserve in the Peters and Cloquet Lease Lands to produce 
concentrated product for 82 years of mining at current extraction rates. 
Little or no commercial ore deposits exist in the Mesabi Lease Lands.

ITEM 3.  LEGAL PROCEEDINGS.

         None.

ITEM 4.  SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS.

         None.

                                     PART II

ITEM 5.  MARKET FOR REGISTRANT'S COMMON EQUITY AND RELATED STOCKHOLDER MATTERS.

         The information set forth in the section titled "Certificates of
Beneficial Interest" on page 14 of the Annual Report of the Trustees of Mesabi
Trust for the fiscal year ended January 31, 1999 is incorporated herein by
reference.

ITEM 6.  SELECTED FINANCIAL DATA.

         The information set forth in the sections titled "Selected Financial
Data" and "Reserves and Distributions" on pages 2 and 14-15, respectively, of
the Annual Report of the Trustees of Mesabi Trust for the fiscal year ended
January 31, 1999 is incorporated herein by reference.


                                       3
<PAGE>

ITEM 7.  TRUSTEES' DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF
         OPERATION.

         The information set forth in the sections titled "Trustees' Discussion
and Analysis of Financial Condition and Results of Operations," "Income and
Expense" and "Reserves and Distributions" on pages 2-7, 13-14 and 14-15,
respectively, of the Annual Report of the Trustees of Mesabi Trust for the
fiscal year ended January 31, 1999 is incorporated herein by reference.

ITEM 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK.

         Not applicable.

ITEM 8.  FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA.

         The financial statements, including the independent auditor's report 
thereon, filed as a part of this report, are presented on pages F-1 through 
F-10 and are incorporated herein by reference.

ITEM 9.  CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND
         FINANCIAL DISCLOSURE.

         None.


                                       4
<PAGE>

                                    PART III

ITEM 10. DIRECTORS AND EXECUTIVE OFFICERS OF THE REGISTRANT.

         There are no directors or executive officers of the registrant. The
Agreement of Trust provides for a Corporate Trustee and four Individual Trustees
(collectively, the "Trustees"). Generally, Trustees continue in office until
their resignation or removal. Any Trustee may be removed at any time, with or
without cause, by the holders of two-thirds in interest of the Trust
Certificates then outstanding. In the case of an Individual Trustee, a successor
is also appointed if the Individual Trustee dies, becomes incapable of acting or
is adjudged bankrupt or insolvent. In the case of the Corporate Trustee, a
successor is also appointed if a receiver of the Corporate Trustee or of its
property is appointed, or if any public officer takes charge or control of the
Corporate Trustee or of its property or affairs for the purpose of
rehabilitation, conservation or liquidation.

         The present Trustees of Mesabi Trust and their respective ages, terms
in office as Trustees, and business experience during the past five years are
set forth in the following table:

<TABLE>
<CAPTION>
                                   Trustee               Business Experience
             Name          Age      Since               During Past Five Years
             ----          ---      -----               ----------------------
<S>                        <C>     <C>         <C>
Bankers Trust Company      N/A       1961      Trust Company

David J. Hoffman           63        1977      Mining geologist; Until January 1988,
                                               President of Towne Mines Exploration
                                               Company, Inc., a privately-held mining
                                               corporation.

Richard G. Lareau          70        1990      Partner in the law firm of Oppenheimer
                                               Wolff & Donnelly LLP; Director of
                                               Ceridian Corporation, Merrill
                                               Corporation, Nash Finch Company and
                                               Northern Technologies International
                                               Corporation.

Ira A. Marshall, Jr.       76        1976      Private investor and self-employed
                                               petroleum engineer; Until February
                                               1986, Director and Vice President of
                                               New American Fund, Inc., a closed-end
                                               investment trust.

Norman F. Sprague III      51        1981      Private investor; Orthopedic surgeon.

</TABLE>


                                       5
<PAGE>

ITEM 11. TRUSTEES' COMPENSATION.

         The Agreement of Trust was amended October 25, 1982 (the "Amendment").
Pursuant to the Amendment, each Individual Trustee receives at least $20,000 in
annual compensation for services as Trustee. Each year, annual Trustee
compensation is adjusted up or down (but not below $20,000) in accordance with
changes from the November 1981 level of 295.5 (the "1981 Escalation Level") in
the All Commodities Producer Price Index (with 1967 = 100 as a base). The All
Commodities Producer Price Index is published by the U.S. Department of Labor.
The adjustment is made at the end of each fiscal year and is calculated on the
basis of the proportion between (a) the level of such index for the November
preceding the end of such fiscal year and (b) the 1981 Escalation Level.

         Also pursuant to the Amendment, Bankers Trust Company, as the Corporate
Trustee, receives annual compensation in an amount equal to the greater of (i)
$20,000, or such other amount determined in accordance with the adjustments
described in the preceding paragraph, or (ii) one quarter of one percent (1/4 of
1%) of the Trust Moneys, exclusive of proceeds of sale of any part of the Trust
Estate (as such terms are defined in the Trust Agreement), received by the
Trustees and distributed to Trust Certificate Holders.

         Additionally, each year the Corporate Trustee receives $62,500 (or
more, if unanimously approved by the Individual Trustees) to cover clerical and
administrative services to Mesabi Trust other than services customarily
performed by a registrar or transfer agent.

         The following table sets forth the cash compensation paid to the
Trustees through January 31, 1999, for services in all capacities as Trustees to
Mesabi Trust during the fiscal year ended January 31, 1999.

<TABLE>
<CAPTION>
                            CASH COMPENSATION TABLE
             (A)                      (B)                          (C)
            Name            Capacity in Which Served        Cash Compensation
            ----            ------------------------        -----------------
<S>                         <C>                             <C>
Bankers Trust Company         Corporate Trustee                  $87,517*

David J. Hoffman              Individual Trustee                 $25,017

Richard G. Lareau             Individual Trustee                 $25,017

Ira A. Marshall, Jr.          Individual Trustee                 $25,017

Norman F. Sprague III         Individual Trustee                 $25,017

</TABLE>

*  Does not include $23,145 of fees and disbursements paid to Bankers Trust
   Company as registrar and transfer agent of the Units.


                                       6
<PAGE>



ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND TRUSTEES.

         The following table sets forth information concerning each person known
to Mesabi Trust to own beneficially more than 5% of the Trust's Units
outstanding as of April 1, 1999. Such information has been obtained from Mesabi
Trust's records and a review of statements filed with Mesabi Trust pursuant to
Section 13(d) of the Securities Exchange Act of 1934 through April 1, 1999.

<TABLE>
<CAPTION>
            Name and Address         Amount of Beneficial      Percent of
         of Beneficial Owner(s)       Ownership of Units          Class
         ----------------------       ------------------          -----
<S>                                  <C>                       <C>
Appaloosa Management L.P.,
 a Delaware Limited Partnership
and
David A. Tepper
26 Main Street
Chatham, New Jersey 07928                  655,500(1)             4.99%

</TABLE>

------------------------

         (1)    According to a Schedule 13D dated May 4, 1998, filed by such
                persons, which indicates that each of such persons has sole
                voting power and sole dispositive power with respect to such
                shares. Appaloosa Management L.P. is general partner of
                Appaloosa Investment Limited Partnership I. The general partner
                of Appaloosa Management L.P. is Appaloosa Partners, Inc., of
                which David Tepper is the sole shareholder and President.
                Appaloosa Management L.P. acts as an investment advisor to
                Palomino Fund Ltd. ("PLF"). Of the 655,500 Units reported,
                327,750 are owned by Appaloosa Investment Limited Partnership I
                and 327,750 are owned by PLF.


         The table below sets forth information as to the Units of Beneficial
Interest in Mesabi Trust beneficially owned as of March 16, 1999 by the Trustees
individually and as a group.

<TABLE>
<CAPTION>
                                  Amount of Beneficial             Percent of
             Name                  Ownership of Units                Class
             ----                  ------------------                -----
<S>                               <C>                             <C>
Bankers Trust Company                             0 (1)                     0

David J. Hoffman                             38,100 (2)           Less than 1%

Richard G. Lareau                            13,000               Less than 1%

Ira A. Marshall, Jr.                         51,000 (3)           Less than 1%

Norman F. Sprague III                        12,700               Less than 1%

All Trustees as a group                     114,800               Less than 1%

</TABLE>

-------------------


                                       7
<PAGE>

(1)      Bankers Trust Company holds, on behalf of various customers, Units in
         its Fiduciary Department in so-called "directed" accounts. Bankers
         Trust Company has no voting or investment power over, and thus no
         beneficial interest in, such Units.

(2)      Includes 15,100 Units owned by Mr. Hoffman's wife, over which Mr.
         Hoffman does not have any investment or voting power and as to which
         Mr. Hoffman disclaims any beneficial ownership.

(3)      These Units consist of (a) 50,000 Units owned indirectly by Mr.
         Marshall through a family trust of which Mr. Marshall is the sole
         trustee and (b) 1,000 Units over which Mr. Marshall has joint voting
         and investment power.


ITEM 13. CERTAIN RELATIONSHIP AND RELATED TRANSACTIONS.

         Mr. Richard G. Lareau, who became a Trustee on March 7, 1990, is a
senior partner in the law firm of Oppenheimer Wolff & Donnelly LLP, of
Minneapolis, Minnesota. That firm has been retained by Mesabi Trust since 1961
to act with respect to matters of Minnesota law, and was retained in 1991 by the
Trustees other than Mr. Lareau to act as general counsel.

                                     PART IV

ITEM 14. EXHIBITS, FINANCIAL STATEMENT SCHEDULES AND REPORTS ON FORM 8-K.

                        (a) 1.    FINANCIAL STATEMENTS:

             The following Financial Statements are incorporated in this
     reporting reference from the pages noted in our Annual Agreement of
     Trustees for the Year Ended January 31, 1999:

         Independent Auditor's Report - page F-1

         Balance Sheets as of January 31, 1999 and 1998 - page F-2

         Statements of Income for the years ended January 31, 1999, 1998 and
         1997 - page F-3

         Statements of Unallocated Reserve and Trust Corpus for the years ended
         January 31, 1999, 1998 and 1997 - page F-4

         Statements of Cash Flows for the years ended January 31, 1999, 1998 and
         1997 - page F-5

         Notes to Financial Statements - pages F-6 through F-10

         2.  FINANCIAL STATEMENT SCHEDULES:

             None required.


                                       8
<PAGE>

         Schedules other than those listed above have been omitted because they
are not applicable or the required information is included in the financial
statements or notes thereto.


                                       9
<PAGE>

   3.   EXHIBITS:

<TABLE>
<CAPTION>

Item No.  Item                               Filing Method
--------  ----                               -------------
<S>       <C>                                <C>
3         Agreement of Trust dated as of
          July 18, 1961..................    Incorporated by reference from
                                             Exhibit 3 to Mesabi Trust's Annual
                                             Report on Form 10-K for the fiscal
                                             year ended January 31, 1987.

3(a)      Amendment to the Agreement of
          Trust dated as of October 25,
          1982...........................    Incorporated by reference from
                                             Exhibit 3(a) to Mesabi Trust's
                                             Annual Report on Form 10-K for the
                                             fiscal year ended January 31, 1988.

4         Instruments defining the rights
          of Trust Certificate Holders...    Incorporated by reference from
                                             Exhibit 4 to Mesabi Trust's Annual
                                             Report on Form 10-K for the fiscal
                                             year ended January 31, 1987.

10(a)     Peters Lease...................    Incorporated by reference from
                                             Exhibits 10(a) - 10(d) to Mesabi
                                             Trust's Annual Report on Form 10-K
                                             for the fiscal year ended January
                                             31, 1987.

10(b)     Amendment Assignment of Peters
          Lease..........................    Incorporated by reference from
                                             Exhibits 10(a) - 10(d) to Mesabi
                                             Trust's Annual Report on Form 10-K
                                             for the fiscal year ended January
                                             31, 1987.

10(c)     Cloquet Lease..................    Incorporated by reference from
                                             Exhibits 10(a) - 10(d) to Mesabi
                                             Trust's Annual Report on Form 10-K
                                             for the fiscal year ended January
                                             31, 1987.

10(d)     Assignment of Cloquet Lease....    Incorporated by reference from
                                             Exhibits 10(a) - 10(d) to Mesabi
                                             Trust's Annual Report on Form 10-K
                                             for the fiscal year ended January
                                             31, 1987.


                                       10
<PAGE>

10(e)     Modification of Lease and
          Consent to Assignment dated
          as of October 22, 1982.........    Incorporated by reference from
                                             Exhibit 10(e) to Mesabi Trust's
                                             Annual Report on Form 10-K for the
                                             fiscal year ended January 31, 1988.

10(f)     Amendment of Assignment,
          Assumption and Further
          Assignment of Peters Lease.....    Incorporated by reference from
                                             Exhibit A to Mesabi Trust's Report
                                             on Form 8-K dated August 17, 1989.

10(g)     Amendment of Assignment,
          Assumption and Further
          Assignments of Cloquet Lease...    Incorporated by reference from
                                             Exhibit B to Mesabi Trust's Report
                                             on Form 8-K dated August 17, 1989.

13.1      Annual Report of the Trustees
          of Mesabi Trust for the fiscal
          year ended January 31, 1999....    Filed herewith.

27.1      Financial Data Schedule........    Filed herewith.

</TABLE>

(b)       REPORTS ON FORM 8-K FILED IN THE FOURTH QUARTER:

          None.


                                       11
<PAGE>

                                   SIGNATURES

         Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the registrant has duly caused this report to be signed on
its behalf by the undersigned, thereunto duly authorized.

Dated:  April 28, 1999
                                 MESABI TRUST


                                 By: Bankers Trust Company
                                     Corporate Trustee

                                 By: /s/ Robert Caporale
                                     -------------------------------------------
                                     Robert Caporale
                                     Vice President


         Pursuant to the requirements of the Securities Exchange Act of 1934,
this report has been signed below by the following persons on behalf of the
registrant and in the capacities and on the dates indicated.

/s/ Robert Caporale                                  April 28, 1999
--------------------------------------------
Robert Caporale
Vice President
Bankers Trust Company

/s/ David J. Hoffman                                 April 28, 1999
--------------------------------------------
David J. Hoffman
Individual Trustee

/s/ Richard G. Lareau                                April 28, 1999
--------------------------------------------
Richard G. Lareau
Individual Trustee

/s/ Ira S. Marshall, Jr.                             April 28, 1999
--------------------------------------------
Ira A. Marshall, Jr.
Individual Trustee

/s/ Norman F. Sprague III                            April 28, 1999
--------------------------------------------
Norman F. Sprague III
Individual Trustee


                                       12