EXHIBIT 4 (u)


                                                                             200
<PAGE>

               Warrant for the purchase of shares of Common Stock

                                                                2,000,000 shares

FOR VALUE RECEIVED, The Tirex Corporation (the "Company"), hereby certifies that
Security Capital Trading,  Inc. or a permitted assignee thereof,  is entitled to
purchase from the Company 2,000,000 fully paid and  nonassessable  shares of the
common stock,  $.001 par value,  of the Company at any time or from time to time
commencing  April 1, 1998 and prior to 5:00 P.M.,  New York city time,  on March
31, 2001, for an aggregate  purchase price of  $766,666.40,  payable as follows:
$.25 per share for the first 666,666 shares to be purchased hereunder,  $.40 per
share for the next 666,666  shares to be purchased  hereunder and $.50 per share
for the remaining 666,667 shares to be purchased  hereunder.  (Hereinafter,  (i)
said common stock, together with any other equity securities which may be issued
by the Company with respect thereto or in substitution  therefor, is referred to
as the "Common Stock," (ii) the shares of the Common Stock purchasable hereunder
or under any other  Warrant  (as  hereinafter  defined)  are  referred to as the
"Warrant  Shares,"  (iii) each holder of the Warrant  Shares is referred to as a
"Warrant  Shareholder"  and all holders of the Warrant  Shares are  collectively
referred to as the "Warrant  Shareholders,"  (iv) the aggregate  purchase  price
payable  hereunder  for the  Warrant  Shares is  referred  to as the  "Aggregate
Warrant Price, " (v) each of the  above-mentioned  prices payable  hereunder for
the  tranche  of  Warrant  Shares  (or  portion  thereof)  to which  such  price
respectively  relates is referred to as the "Per Share Warrant Price," (vi) this
Warrant,  all  identical  warrants  issued on the date  hereof and all  warrants
hereafter  issued in exchange  or  substitution  for this  Warrant or such other
warrants are referred to as the Warrants" and (vi) the holder of this Warrant is
referred  to as the  "Holder"  and the  holder  of this  Warrant  and all  other
Warrants are referred to as the "Holders").  The Aggregate  Warrant Price is not
subject to  adjustment.  The Per Share Warrant Price is subject to adjustment as
hereinafter provided; in the event of any such adjustment, the number of Warrant
Shares  shall be adjusted by dividing  the  Aggregate  Warrant  Price by the Per
Share Warrant Price in effect immediately after such adjustment.

1. Exercise of Warrant.

      a) Exercise for Cash

      This Warrant may be  exercised,  in whole at any time or in part from time
      to time,  commencing  April 1, 1998, and prior to 5:00 P.M., New York City
      time,  on March 31, 2001,  by the Holder by the  surrender of this Warrant
      (with  the  subscription  form at the end  hereof  duly  executed)  at the
      address set forth in Subsection 9(a) hereof,  together with proper payment
      of the Aggregate Warrant Price, or the proportionate  part thereof if this
      Warrant is exercised in part.  Payment for Warrant Shares shall be made by
      certified or official bank check  payable to the order of the Company.  If
      this Warrant is exercised  in part,  this Warrant must be exercised  for a
      number of whole shares of the Common Stock.  and the Holder is entitled lo
      receive a new  Warrant  Covering  the Warrant  Shares  which have nor been
      exercised  and  setting  forth  the  proportionate  part of the  Aggregate
      Warrant Price  applicable to such Warrant  Shares.  Upon such surrender of
      this Warrant the Company will (a) issue a certificate or  certificates  in
      the name of the  Holder  for the  largest  number  of whole  shares of the
      Common Stock to which the Holder shall be entitled and, if this Warrant is
      exercised in whole, in lieu of any fractional share of the Common Stock to
      which the Holder  shall be  entitled,  pay to the Holder cash in an amount
      equal to the fair market value of such  fractional  share  (determined  in
      such  reasonable  manner as the Board of  Directors  of the Company  shall
      determine), and (b) deliver the other securities and properties receivable
      upon the exercise of this Warrant,  or the  proportionate  part thereof if
      this  Warrant is  exercised in part,  pursuant to the  provisions  of this
      Warrant.


                                                                             201
<PAGE>

      b) Cashless Exercise

      In lieu of exercising this Warrant in the manner set forth in Subsection
      1(a) above, the Warrant may be exercised by surrender of the Warrant
      without payment of any other consideration, commission or remuneration, by
      execution of the cashless exercise subscription form (at the end hereof,
      duly executed). The number of shares to be issued in exchange for the
      Warrant will be computed by subtracting the Per Share Warrant Price from
      the closing bid price of the Common Stock on the date of receipt of the
      cashless exercise subscription form, multiplying that amount by the number
      of shares represented by the Warrant, and dividing by the closing bid
      price as of the same date.

2.    Reservation of Warrant Shares.

      The Company agrees that, prior to the expiration of this Warrant, the
      Company will at all times have authorized and in reserve, and will keep
      available, solely for issuance or delivery upon the exercise of this
      Warrant, the shares of the Common Stock and other securities and
      properties as from time to time shall be receivable upon the exercise of
      this Warrant, free and clear of all restrictions on sale or transfer
      (except for applicable state or federal securities law restrictions) and
      free and clear of all pre-emptive rights.

3.    Protection Against Dilution.

      a)    If, at any time or from time to time after the date of this Warrant,
            the Company shall issue or distribute (for no consideration) to the
            holders of shares of Common Stock evidences of its indebtedness, any
            other securities of the Company or any cash, property or other
            assets (excluding a subdivision, combination or reclassification, or
            dividend or distribution payable in shares of Common Stock, referred
            to in Subsection 3(b), and also excluding cash dividends or cash
            distributions paid out of net profits legally available therefor if
            the full amount thereof, together with the value of other dividends
            and distributions made substantially concurrently therewith or
            pursuant to a plan which includes payment thereof, is equivalent to
            not more than 5% of the Company's net worth) (any such nonexcluded
            event being herein called a "Special Dividend"), the Per Share
            Warrant Price shall be adjusted by multiplying the Per Share Warrant
            Price then in effect by a fraction, the numerator of which shall be
            the then current market price of the Common Stock (defined as the
            average for the thirty consecutive business day immediately prior to
            the record date of the daily closing price of the Common Stock as
            reported by the principal exchange or market on which the Common
            Stock is listed) less the fair market Common Stock is listed) less
            the fair market value (as determined by the Company's Board of
            Directors) of the evidences of indebtedness,


                                                                             202
<PAGE>

            securities or property, or other assets issued or distributed in
            such Special Dividend applicable to one share of Common Stock and
            the denominator of which shall be such then current market price per
            share of Common Stock. An adjustment made pursuant to this
            Subsection 3(a) shall become effective immediately after the record
            date of any such Special Dividend.

      b)    In case the Company shall hereafter (i) pay a dividend or make a
            distribution on its capital stock in shares of Common Stock, (ii)
            subdivide its outstanding shares of Common Stock into a greater
            number of shares, (iii) combine its outstanding shares of Common
            Stock into a smaller number of shares or (iv) issue by
            reclassification of its Common Stock any shares of capital stock of
            the Company, the Holder or Holders of this Warrant shall thereafter
            be entitled, upon exercise of this Warrant, to receive the number
            and kind of shares which, if this Warrant had been exercised
            immediately prior to the happening of such event, the Holder or
            Holders would have owned upon such exercise, and would have been
            entitled to receive upon consummation of such dividend,
            distribution, subdivision, combination or reclassification. An
            adjustment made pursuant to this Subsection 3(b) shall become
            effective immediately after the record date in the case of a
            dividend or distribution and shall become effective immediately
            after the effective date in the case of a subdivision, combination
            or reclassification. Whenever the number of shares of Common Stock
            purchasable upon exercise of this Warrant is adjusted pursuant to
            this Subsection 3(b), each Per Share Warrant Price shall be adjusted
            simultaneously therewith by multiplying the Per Share Warrant Price
            then in effect by a fraction, the numerator of which shall be the
            number of Warrant Shares purchasable at each Per Share Warrant Price
            upon exercise of this Warrant immediately prior to such adjustment,
            and the denominator of which shall be the number of Warrant Shares
            purchasable at each Per Share Warrant Price upon exercise of this
            Warrant immediately after such adjustment, so that the Aggregate
            Warrant Price shall remain the same. If, as a result of an
            adjustment made pursuant to this Subsection 3(b), the Holder of any
            Warrant thereafter surrendered for exercise shall become entitled to
            receive shares of two or more classes of capital stock or shares of
            Common Stock and other capital


                                                                             203
<PAGE>

            stock of the Company, the Board of Directors (whose determination
            shall be conclusive and shall be described in a written notice to
            the Holder of any Warrant promptly after such adjustment) shall
            determine the allocation of the adjusted Per Share Warrant Price
            between or among shares of such classes or capital stock or shares
            of Common Stock and other capital stock.

      c)    Except as provided in Subsection 3(e), in case the Company shall
            hereafter issue or sell any shares of Common Stock for a
            consideration per share less than the Per Share Warrant Price on the
            date of such issuance or sale, the Per Share Warrant Price shall be
            adjusted as of the date of such issuance or sale so that the same
            shall equal the consideration per share received by the Company upon
            such issuance or sale; provided, however, that no adjustment of the
            Per Share Warrant Price shall be required (i) unless the market
            price of the Common Stock (as defined in Section 3(a) hereof) on the
            date of such issuance or sale shall be equal to or greater than 250%
            of the applicable Per Share Warrant Price; or (ii) if such issuance
            or sale shall be effected (x) in connection with the exercise of
            warrants, options or conversion rights outstanding on April 1,1998;
            (y) pursuant to the terms of employment or consulting agreements to
            which the Company is a party and which were in effect on the date of
            issuance of this Warrant; or (z) pursuant to an offer in effect on
            March 31, 1998 (the "506 Offering") to sell securities of the
            Company in a private placement pursuant to Rule 506 of Regulation D
            promulgated by the Securities and Exchange Commission under the
            Securities Act of 1933, as amended (the "Act").

      d)    Except as provided in Subsection 3(a) and 3(e), in case the Company
            shall hereafter issue or sell any rights, options, warrants or
            securities convertible into Common Stock entitling the holders
            thereof to purchase Common Stock or to convert such securities into
            Common Stock at a price per share (determined by dividing (i) the
            total amount, if any, received or receivable by the Company in
            consideration of the issuance or sale of such rights, options,
            warrants or convertible securities plus the total consideration, if
            any, payable to the Company upon exercise or conversion thereof (the
            "Total Consideration") by (ii) the number of additional shares of


                                                                             204
<PAGE>

            Common Stock issuable upon exercise or conversion of such
            securities) less than the then current Per Share Warrant Price in
            effect on the date of such issuance or sale, the Per Share Warrant
            Price shall be adjusted as of the date of such issuance or sale so
            that the same shall equal the price determined by dividing (i) the
            sum of (a) the number of shares of Common Stock outstanding on the
            date of such issuance or sale multiplied by the Per Share Warrant
            Price plus (b) the Total Consideration by (ii) the number of shares
            of Common Stock outstanding on the date of such issuance or sale
            plus (iii) the maximum number of additional shares of Common Stock
            issuable upon exercise or conversion of such securities; provided,
            however, that no adjustment of the Per Share Warrant Price shall be
            required (i) unless the market price of the Common Stock (as defined
            in Section 3(a) hereof) on the date of such issuance or sale shall
            be equal to or greater than 250% of the applicable Per Share Warrant
            Price; or (ii) if such issuance or sale shall be effected (x)
            pursuant to the terms of employment or consulting agreements to
            which the Company is a party and which were in effect on the date of
            issuance of this Warrant; or (y) pursuant to the 506 Offering.

      e)    In case of any capital reorganization or reclassification, or any
            consolidation or merger to which the Company is a party other than a
            merger or consolidation in which the Company is the continuing
            corporation, or in case of any sale or conveyance to another entity
            of the property of the Company as an entirety or substantially as an
            entirety, or in the case of any statutory exchange of securities
            with another corporation (including any exchange effected in
            connection with a merger of a third corporation into the Company),
            the Holder of this Warrant shall have the right thereafter to
            convert such Warrant into the kind and amount of securities, cash or
            other property which he would have owned or have been entitled to
            receive immediately after such reorganization, reclassification,
            consolidation, merger, statutory exchange, sale or conveyance had
            this Warrant been converted immediately prior to the effective date
            of such reorganization, reclassification, consolidation, merger,
            statutory exchange, sale or conveyance and in any such case, if
            necessary, appropriate adjustment shall be made in the application
            of the provisions set forth in this Section 3 with


                                                                             205
<PAGE>

            respect to the rights and interests thereafter of the Holder of this
            Warrant to the end that then provisions set forth in this Section 3
            shall thereafter correspondingly be made applicable as nearly as may
            reasonably be, in relation to any shares of stock or other
            securities or be, in relation to any shares of stock or other
            securities or property thereafter deliverable on the conversion of
            this Warrant. The above provisions of this Subsection 3(e) shall
            similarly apply to successive reorganizations, reclassifications,
            consolidations, mergers, statutory exchanges, sales or conveyances.
            The issuer of any shares of stock or other securities or property
            thereafter deliverable on the conversion of this Warrant shall be
            responsible for all of the agreements and obligations of the Company
            hereunder. Notice of any such reorganization, reclassification,
            consolidation, merger, statutory exchange, sale or conveyance and of
            said provisions so proposed to be made, shall be mailed to the
            Holders of the Warrants not less than 10 days prior co such event. A
            sale of all or substantially all of the assets of the Company for a
            consideration consisting primarily of securities shall be deemed a
            consolidation or merger for the foregoing purposes.

      f)    No adjustment in the Per Share Warrant price shall be required
            unless such adjustment would require an increase or decrease of at
            least $0.05 per share of Common Stock; provided, however, that any
            adjustments which by reason of this Subsection 3(f) are not required
            to be made shall be carried forward and taken into account in any
            subsequent adjustment; provided further, however, that adjustments
            shall be required and made in accordance with the provisions of this
            Section 3 (other than this Subsection 3(f)) nor later than such time
            as may be required in order to preserve the tax-free nature of a
            distribution to the Holder of this Warrant or Common Stock issuable
            upon exercise hereof. All calculations under this Section 3 shall be
            made to the nearest cent. Anything in this Section 3 to the contrary
            notwithstanding, the Company shall be entitled to make such
            reductions in the Per Share Warrant Price, in addition to chose
            required by this Section 3, as it in its discretion shall deem to be
            advisable in order that any stock dividend, subdivision of shares or
            distribution of rights to purchase stock or securities convertible
            or exchangeable for stock hereafter


                                                                             206
<PAGE>

            made by the Company to its shareholders shall not be taxable.

      g)    Whenever the Per Share Warrant Price is adjusted as provided in this
            Section and upon any modification of the rights of a Holder of
            Warrants in accordance with this Section 3, the Company shall
            promptly obtain, at its expense, a certificate of a firm of
            independent public accountants of recognized standing selected by
            the Board of Directors (who may be the regular auditors of the
            Company) setting forth the Per Share Warrant Price and the number of
            Warrant Shares after such adjustment or the effect of such
            modification, a brief statement of the facts requiring such
            adjustment or modification and the manner of computing the same and
            cause copies of such certificate to be mailed to the Holders of the
            Warrants.

      h)    If the Board of Directors of the Company shall declare any dividend
            or other distribution with respect to the Common Stock, other than a
            cash distribution out of earned surplus, the Company shall mail
            notice thereof to the Holders of the Warrants not less than 10 days
            prior to the record date fixed for determining shareholders entitled
            to participate in such dividend or other distribution.

4.    Fully Paid Stock. Taxes.

      The Company agrees that the shares of the Common Stock represented by each
      and every certificate for Warrant Shares delivered on the exercise of this
      Warrant shall, at the time of such delivery, be validly issued and
      outstanding, fully paid and nonassessable, and not subject to pre-emptive
      rights, and the Company will take all such actions as may be necessary to
      assure that the par value or stated value, if any, per share of the Common
      Stock is at all times equal to or less than the then Per Share Warrant
      Price. The Company further covenants and agrees that it will pay, when due
      and payable, any and all Federal and state stamp, original issue or
      similar taxes which may be payable in respect of the issue of any Warrant
      Share or certificate therefor.

5.    Registration Under Securities Act of 1933.

      a)    The Company agrees that if, at any time and from time to time during
            the period commencing on the date of execution of this Warrant and
            ending on March 31, 2001, the Company shall undertake to prepare and
            file a registration statement or a post-effective amendment to a
            registration statement (any such registration statement being
            hereinafter called a "Subsequent Registration Statement") under the
            Act, other than a registration statement on Form S-8 or any other
            form which


                                                                             207
<PAGE>

            does not include substantially the same information as would be
            required in a form for the general registration of securities) in
            connection with the proposed offer of any of its securities by it or
            any of its shareholders, the Company will (i) promptly notify the
            Holder and each of the Holders, if any, of other Warrants and/or any
            Warrant Shareholders that such Subsequent Registration Statement
            will be filed and that the Warrant Shares which are then held,
            and/or which may be acquired upon the exercise of the Warrants, by
            the Holder and such Holders, will at the Holder's and such Holders'
            and/or such Warrant Shareholders' request, be included in such
            Subsequent Registration Statement, (ii) include in the securities
            covered by such Subsequent Registration Statement all Warrant Shares
            which it has been so requested to include, all at the Company's sole
            cost and expense, (iii) use its best efforts to cause such
            Subsequent Registration Statement to become effective as soon as
            practicable and (iv) take all other action necessary under any
            Federal or state law or regulation of any governmental authority to
            permit all Warrant Shares which it has been so requested to include
            in such Subsequent Registration Statement or to be sold or otherwise
            disposed of, and will maintain such compliance with each such
            Federal and state law and regulation of any governmental authority
            for the period necessary for the Holder and such Holders to effect
            the proposed sale or other disposition. Provided, however, that the
            Holders shall be obligated to agree in writing, if so requested by
            the underwriter or representative of the underwriters of the public
            offering to be made pursuant to such Subsequent Registration
            Statement, not to sell, assign, transfer, pledge, hypothecate or
            otherwise dispose of such Warrant Shares for a period of not more
            than one year from the effective date of such Subsequent
            Registration Statement.

      b)    Whenever the Company is required pursuant to the provisions of this
            Section 5 to include Warrant Shares in a registration statement or a
            post-effective amendment to a registration statement, the Company
            shall (i) furnish each Holder and/or Warrant Shareholder and each
            underwriter of such Warrant Shares with such copies of the
            prospectus, including the preliminary prospectus, conforming to the
            Act, (and such other documents as each such Holder, Warrant
            Shareholder or each such


                                                                             208
<PAGE>

            underwriter may reasonably request) in order to facilitate the sale
            or distribution of the Warrant Shares, (ii) use its best efforts to
            register or qualify such Warrant Shares under the blue sky laws (to
            the extent applicable) of such jurisdiction or jurisdictions as the
            Holders, Warrant Shareholders and each underwriter of Warrant Shares
            being sold by such Holders and/or Warrant Shareholders shall
            reasonably request and (iii) take such other actions as may be
            reasonably necessary or advisable to enable such Holders, Warrant
            Shareholders and such underwriters to consummate the sale or
            distribution in such jurisdiction or jurisdictions in which such
            Holders and Warrant Shareholders shall have reasonably requested
            that the Warrant Shares be sold.

      c)    The Company shall pay all expenses incurred in connection with any
            registration or other action pursuant to the provisions of this
            Section 5, other than underwriting discounts, non-accountable
            expenses, if any and applicable transfer taxes relating to the
            Warrant Shares.

      d)    The Company will indemnify the Holders and Warrant Shareholders who
            have included their respective securities in each Subsequent
            Registration Statement substantially to the same extent as the
            indemnification provided to the underwriters of the offering to be
            made pursuant the underwriting agreement to be executed upon
            effectiveness of such Subsequent Registration statement, and such
            Holders and/or Warrant Shareholders will indemnify the Company (and
            the underwriters, if applicable) with respect to information
            furnished by them in writing to the Company for inclusion therein
            substantially to the same extent as the indemnification to be
            provided by the underwriters to the Company pursuant to such
            underwriting agreement.

6.    Transferability.

      The Company may treat the registered Holder of this Warrant as he or it
      appears on the Company's books at any time as the Holder for all purposes.
      The Company shall permit any Holder of a Warrant or his duly authorized
      attorney, upon written request during ordinary business hours, to inspect
      and copy or make extracts from its books showing the registered holders of
      Warrants. All warrants issued upon the transfer or assignment of this
      Warrant will be dated the same date as this Warrant, and all rights of the
      Holders thereof shall be identical to those of the Holder.


                                                                             209
<PAGE>

7.    Loss etc. of Warrant.

      Upon receipt of evidence satisfactory to the Company of the loss, theft,
      destruction or mutilation of this Warrant, and of indemnity reasonably
      satisfactory to rye Company, if lost, stolen or destroyed, and upon
      surrender and cancellation of dais Warrants if mutilated, the Company
      shall execute and deliver to the Holder a new Warrant of like date, tenor
      and denomination.

8.    Warrant Holders Not Shareholders.

      Except as otherwise provided herein, this Warrant does not confer upon the
      Holder any right to vote or to consent to or receive notice as a
      shareholder of the Company, as such, in respect of any matters whatsoever,
      or any other rights or liabilities as a shareholder, prior to the exercise
      hereof.

9.    Communication.

      No notice or other communication under this Warrant shall be effective
      unless, but any notice or other communication shall be effective and shall
      be deemed to have been given if, the same is in writing and is mailed by
      first-class mail, postage prepaid, addressed to:

      a)    the Company at 740 St. Maurice, Suite 201, Montreal, Quebec H3C 1L5
            or such other address as the Company has designated in writing to
            the Holder; or

      b)    the Holder at 520 Madison Avenue, New York, New York 10022, or such
            other address as the Holder has designated in writing to the
            Company.

10.   Headings.

      The headings of this Warrant have been inserted as a matter of convenience
      and shall nor affect the construction hereof.

11.   Applicable Law.

      This Warrant shall be governed by and construed in accordance with the law
      of the State of New York without giving effect to the principles of
      conflicts of law thereof.

IN WlTNESS WHEREOF, The Tirex Corporation has caused this Warrant to be signed
by its Chairman and its corporate seal to be hereunto affixed by its Secretary
as of, and with effect from this 1st day of April, 1998.

ATTEST:

Secretary

[Corporate Seal]


THE TIREX CORPORATION

By:


                                                                             210
<PAGE>

Name: Title:

                                  SUBSCRIPTION

The undersigned, , pursuant to the provisions of the foregoing Warrant, hereby
agrees to subscribe for and purchase shares of the Common Stock of The Tirex
Corporation covered by said Warrant, and makes payment therefor in full at the
price per share provided by said Warrant.

Dated: ______________                        Signature:_________________________

                                             Address:___________________________
                                             ___________________________________
                                             ___________________________________
                                             
                                   ASSIGNMENT

      FOR VALUE RECEIVED hereby sells, assigns and transfers unto the foregoing
Warrant and all rights evidenced thereby, and does irrevocably constitute and
appoint , attorney, to transfer said Warrant on the books of The Tirex
Corporation

Dated: ______________                        Signature:_________________________

                                             Address:___________________________
                                             ___________________________________
                                             ___________________________________


                                                                             211
<PAGE>

                               PARTIAL ASSIGNMENT

FOR VALUE RECEIVED unto the right to purchase hereby assigns and transfers ~ l
shares of the Common Stock of The Tirex Corporation by the foregoing Warrant,
and a proportionate part of said Warrant and the rights evidenced hereby, and
does irrevocably constitute and appoint attorney, to transfer that part of said
Warrant on the books of The Tirex Corporation

Dated: ______________                        Signature:_________________________

                                             Address:___________________________
                                             ___________________________________
                                             ___________________________________


                         CASHLESS EXERCISE SUBSCRIPTION

The undersigned pursuant to the provisions of the foregoing Warrant, hereby
agrees to subscribe for shares of the Common Stock of The Tirex Corporation, and
makes payment therefor in full in accordance with the formula set forth in
paragraph l(b) of the Warrant, by surrender and delivery of this Warrant.

Dated: ______________                        Signature:_________________________

                                             Address:___________________________
                                             ___________________________________
                                             ___________________________________


                                      212