STOCK PLEDGE AGREEMENT

         THIS STOCK PLEDGE  AGREEMENT  ("Agreement") is made and entered into as
of the 15th day of December,  2000 by and among Altair  International,  Inc., an
Ontario  corporation  ("Pledgor")  and Doral 18, LLC, a Cayman  Islands  limited
liability company ("Pledgee").

                              Preliminary Statement
                              ---------------------

         A. Pledgor and Pledgee have agreed to enter into a Securities  Purchase
Agreement dated as of December 15, 2000 (the  "Securities  Purchase  Agreement")
pursuant  to which  Pledgee  has agreed to  purchase  from  Pledgor (i) an Asset
Backed  Exchangeable  Term  Note  in the  form  of  Exhibit  A  attached  to the
Securities  Purchase Agreement (the "Note") and a Warrant in the form of Exhibit
B attached to the Securities Purchase Agreement (the "Warrant").

         B. Pledgor owns one hundred  percent (100%) of the shares of the common
stock (the  "Securities") of Mineral Recovery Systems,  Inc.  ("Mineral Recovery
Systems"), a Nevada corporation.

         C.  Mineral  Recovery  Systems  is a  wholly-owned  subsidiary  of  the
Pledgor.  Mineral Recovery Systems owns certain  leasehold  interests in mineral
deposits as  described in various  Memoranda  of Mineral  Leases as set forth in
Exhibit A attached hereto.

         D. As security for the payments to be made to Pledgee by Pledgor  under
the Note,  Pledgor  desires to pledge the Securities to Pledgee as Collateral on
the Note.

         NOW,  THEREFORE,  in consideration of the premises set forth herein, it
is hereby agreed as follows:

         1. Collateral.  The term "Collateral" shall mean the Securities and all
dividends,  distributions  and other amounts or  additional  securities to which
Pledgor (with or without  additional  consideration)  is or becomes  entitled by
virtue  of  its  ownership  of any of the  Securities  or as the  result  of any
corporate reorganization,  merger,  consolidation,  stock split, stock dividend,
conversion, preemptive right or otherwise, and the proceeds thereof.

         2.  Deposit  of   Collateral.   To  secure  payment  of  the  Pledgor's
obligations  under the Loan  Agreement,  Pledgor hereby pledges and deposits the
Securities with Pledgee and hereby grants to Pledgee a valid and perfected first
lien  on and  security  interest  in  the  Securities  and  other  items  of the
Collateral.

         3.  Representations  and  Warranties.  Pledgor  hereby  represents  and
warrants to Pledgee  that as to the  Collateral  deposited  by such Pledgor with
Pledgee on the date  hereof,  (i) Pledgor is the legal and  beneficial  owner of
such  Collateral;  (ii)  such  Collateral  is  validly  issued,  fully  paid and
non-assessable  and is  registered  in the name of Pledgor;  (iii) the pledge of
Collateral  pursuant  to the terms of this  Agreement,  together  with  delivery
thereof,  creates a valid and perfected  first lien on and security  interest in
such  Collateral  in favor of  Pledgee;  (iv) the stock  power  attached  to the
certificate(s)   representing  such  Collateral  have  been  duly  executed  and
delivered by Pledgor to Pledgee;  (v) none of such  Collateral is subject to any
lien, except for the perfected first security interest granted to Pledgee hereby

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and, so long as any portion of the Note remains unpaid,  Pledgor will not create
or permit to exist any lien upon or with respect to such Collateral  without the
consent of Pledgee;  (vi) Pledgor  will not sell,  transfer,  convey,  assign or
otherwise divest its interests in such Collateral,  or any part thereof,  to any
other person; (vii) Pledgor hereby represents and warrants that Mineral Recovery
Systems  currently  has  good and  valid  title to the  leasehold  interests  as
described in the Memoranda of Mineral  Leases as set forth in Exhibit A attached
hereto, and the same are not subject to any liens,  security  interests,  suits,
judgments or any other encumbrances;  and (viii) Pledgor shall not cause Mineral
Recovery  Systems to sell,  transfer,  convey,  assign or  otherwise  divest its
interests in the leasehold  interests,  or any part thereof, to any other person
nor will Pledgor  permit Mineral  Recovery  Systems to create or permit to exist
any lien on any leasehold interest during the term hereof.

         4.       Stock Splits, Stock Dividends, Etc.
                  ----------------------------------

                  4.1 Pledgor agrees that if by virtue of Pledgor's ownership of
the   Collateral,   Pledgor  becomes   entitled  (with  or  without   additional
consideration) to other or additional  securities as the result of any corporate
reorganization,  merger, consolidation,  stock split, stock dividend, conversion
or preemptive right or otherwise, such Pledgor shall:

         4.1.1  Cause the  issuer of such  additional  securities  to deliver to
Pledgee  the  certificates  evidencing  Pledgor's  ownership  thereof and hereby
authorizes and empowers Pledgee to demand the same from such issuer,  and agrees
if such  certificates  are delivered to Pledgor,  to take possession  thereof in
trust for Pledgee;

         4.1.2 Deliver to Pledgee a stock power with respect to such securities,
executed in blank by Pledgor;

         4.1.3  Deliver to  Pledgee  such  other  certificates,  forms and other
instruments as Pledgee may request in connection with such pledge.

                  4.2  Pledgor  agrees  that such  additional  securities  shall
constitute a portion of the Collateral  and be subject to this Pledge  Agreement
in the same manner and to the same extent as the  securities  pledged  hereby to
Pledgee on the date hereof.

         5. Dividend  Rights/Voting  Power. Unless and until an Event of Default
shall have  occurred  under the Note and such default  shall not have been cured
within the  applicable  cure  period,  Pledgor  shall be entitled to receive all
dividends  paid on the  Securities  and to  exercise  all  voting  powers in all
corporate matters  pertaining to the Collateral for any purpose not inconsistent
with, or in violation of, the provisions of the Securities Purchase Agreement or
the Note.

                                        2

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         6.       Default and Remedies.
                  --------------------

                  6.1 If an Event of Default shall occur under the Note and such
default shall not have been cured within the applicable cure period, Pledgee, at
its option, may:

                           6.1.1 Cause the  Collateral  to be  registered in its
         name or in the name of its nominee;

                           6.1.2  Exercise all voting  powers  pertaining to the
         Collateral  and  otherwise act with respect  thereto as though  Pledgee
         were the owner thereof;

                           6.1.3   Receive   all   dividends   and   all   other
         distributions of any kind whatsoever on all or any of such Collateral;

                           6.1.4  Exercise  any and all  rights  of  collection,
         conversion  or  exchange,  and any and all  other  rights,  privileges,
         options or powers of Pledgor pertaining or relating to the Collateral;

                           6.1.5 Sell,  assign and  deliver  the whole,  or from
         time to time, any part of such  Collateral at any private sale, with or
         without demand for performance or advertisement of the time or place of
         sale or  adjournment  thereof or otherwise,  and free from any right of
         redemption  (all of which hereby  expressly  are waived by Pledgor) for
         cash,  for  credit  or for  other  property,  for  immediate  or future
         delivery,  and for such  price and on such terms as Pledgee in its sole
         discretion may determine; and

                           6.1.6 Exercise any other remedy specifically  granted
         under this Agreement or now or hereafter  existing in equity or at law,
         by virtue of statute or otherwise.

With  respect to the actions  described in each of  subsections  6.1.2 and 6.1.4
above, Pledgor hereby irrevocably constitutes and appoints Pledgee its proxy and
attorney-in-fact  with full  power of  substitution  and  acknowledges  that the
constitution and appointment of such proxy and attorney-in-fact are coupled with
an interest and are irrevocable.

                  6.2 At any sale made  pursuant to Section  6.1 above,  Pledgee
may bid for and  purchase,  free from any right or equity of  redemption  on the
part of the Pledgor (the same hereby being waived and released by Pledgor),  any
part or all of the  Collateral  that is  offered  for sale,  and  Pledgee,  upon
compliance  with the  terms  of sale and  other  applicable  federal  regulatory
requirements,  may hold,  retain and dispose of such Collateral  without further
accountability therefor.

                  6.3 Pledgee  shall apply the proceeds of any sale of the whole
or any part of the  Collateral  and any other monies at the time held by Pledgee
under the provisions of this Agreement in satisfaction of the Note.

                                        3

<PAGE>

                  6.4  Pledgee  shall not have any duty to  exercise  any of the
rights,  privileges,  options or powers or, except as otherwise required by law,
to sell  or  otherwise  realize  upon  any of the  Collateral,  as  hereinbefore
authorized,  and Pledgee  shall not be  responsible  for any failure to do so or
delay in so doing.

                  6.5 Any sale of all or any portion of the Collateral  pursuant
to Section 6.1 above shall  operate to divest all right,  title and  interest of
the Pledgor to the Collateral which is the subject of any such sale.

                  6.6 Pledgor  acknowledges that Pledgee may be unable to effect
a public sale of all or a part of the Collateral or that it may be able to do so
only after delay which might  adversely  affect the value that might be realized
upon the sale of the  Collateral.  Accordingly,  Pledgor agrees that Pledgee may
sell  the  Collateral  or any part  thereof  in one or more  private  sales to a
restricted group of purchasers who may be required to agree, among other things,
that they are acquiring the  Collateral  for their own account,  for  investment
purposes only, and not with a view toward the  distribution  or resale  thereof.
Pledgor  agrees  that any such  private  sale may be at prices or on terms  less
favorable  to the  owner  of the  Collateral  than  would  be the  case  if such
Collateral  was sold at public sale, and that any such private sale shall not be
deemed not to have been made in a  commercially  reasonable  manner by virtue of
such sale having been a private sale.

                  6.7 Pledgee  shall give not less than ten (10)  business  days
prior  written  notice to the Pledgor of any sale  pursuant  to this  Section 6.
Pledgor hereby agrees that such notice is commercially reasonable.

         7. Pledgee's  Obligations,  Custodial  Agreement,  Performance  Rights,
Pledge Does Not Make  Pledgee  Shareholder.  Pledgee  shall not have any duty to
protect,  preserve or enforce rights against the Collateral other than a duty of
reasonable  custodial care of any such  Collateral in its  possession,  it being
understood  that Pledgee shall have no  responsibility  for (i)  ascertaining or
taking action with respect to calls, conversions, exchanges, maturities, tenders
or other matters  relating to the  Collateral,  whether or not Pledgee has or is
deemed to have knowledge of such matters,  or (ii) taking any necessary steps to
preserve  rights  against any parties with respect to the  Collateral,  or (iii)
making any capital  contributions  or other  payments on behalf of Pledgor  with
respect to the Collateral.

         8.  Termination of Pledge  Agreement.  The Pledgee shall deliver to the
Pledgor the Collateral in its possession and this Agreement  thereupon  shall be
terminated  upon the earlier to occur of (i) the payment and performance in full
of all amounts  due under the Note or (ii) at such time after the  effectiveness
of the resale registration statement on Form S-3 to be filed with Securities and
Exchange  Commission  pursuant  to the terms and  conditions  of the  Securities
Purchase  Agreement which covers the resale of the shares of Common Stock of the
Pledgor by the Pledgee (the "Registration  Statement") when the closing price of
the Pledgor's  common shares on its principal  exchange has been above $2.25 for
five consecutive days.

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         9. Delivery of Additional Collateral.
            ---------------------------------

         Within  five (5)  business  days of the  execution  of this  Agreement,
Pledgor shall be obligated to deliver to Pledgee a fully executed  original copy
of an Absolute Assignment of Leases and Rents substantially in the form attached
hereto as Exhibit A (the "Lease Assignment")  covering Mineral Recovery Systems'
interests  in the mineral  deposits  which are  described  in the  Memoranda  of
Mineral Leases set forth in Exhibit B attached hereto (the "Mineral Leases"). In
the event the  Registration  Statement does not become  effective on or prior to
the 180th day after the date hereof  and/or the closing  price of the  Pledgor's
common  shares  on its  principal  exchange  has not been  above  $2.25 for five
consecutive  days  during  such  180  day  period,  the  Pledgee,  at the at the
Pledgor's  sole  cost and  expense,  shall  be  entitled  to  record  the  Lease
Assignment in the proper jurisdictions to perfect Pledgee's security interest in
Mineral Leases. Upon the effectiveness of the Registration Statement and at such
time as the  closing  price of the  Pledgor's  common  shares  on its  principal
exchange has been above $2.25 for five  consecutive  days,  the Pledgee shall no
longer be entitled to record the Lease Assignment and shall  immediately  return
the Lease  Assignment to Pledgor or if the Lease  Assignment has previously been
recorded,  the Pledgee shall immediately  record a document in a form sufficient
to release the security  interest  created through the prior  recordation of the
Lease Assignment in the proper jurisdictions.

         10.      Miscellaneous.
                  -------------

                  10.1 Each and every right, remedy and power granted to Pledgee
hereunder  shall be  cumulative  and in addition to any other  right,  remedy or
power  specifically  granted herein or now or hereafter existing in equity or at
law, by virtue of statute or otherwise  and may be  exercised  by Pledgee,  from
time to time,  concurrently or  independently  and as often and in such order as
Pledgee  may deem  expedient.  Any  failure  or delay on the part of  Pledgee in
exercising any such right,  remedy or power, or abandonment or discontinuance of
steps to  enforce  the same,  shall not  operate  as a waiver  thereof or affect
Pledgee's  right  thereafter  to  exercise  the same,  and any single or partial
exercise of any such right,  remedy or power shall not preclude any other right,
remedy or power,  and no such failure,  delay,  abandonment or single or partial
exercise of Pledgee's  rights hereunder shall be deemed to establish a custom or
course of dealing or performance among the parties hereto.

                  10.2 Any  modification  or  waiver  of any  provision  of this
Agreement,  or any consent to any departure by Pledgor  therefrom,  shall not be
effective in any event unless the same is in writing and signed by Pledgee,  and
then  such  modification,  waiver  or  consent  shall be  effective  only in the
specific instance and for the specific purpose given. Any notice to or demand on
Pledgor in any event not  specifically  required of Pledgee  hereunder shall not
entitle Pledgor to any other or further notice or demand in the same, similar or
other circumstances unless specifically required hereunder.

                  10.3 Pledgor  agrees that at any time,  and from time to time,
after the  execution and delivery of this  Agreement,  Pledgor  shall,  upon the
request of Pledgee and at the expense of Pledgor,  promptly  execute and deliver
such  further  documents  and do such  further  acts and things as  Pledgee  may
request in order to effect fully the purposes of this  Agreement  and to subject
to the security  interest created hereby any property intended by the provisions
hereof to be covered hereby.

                                        5

<PAGE>

                  10.4 Pledgor agrees that it will warrant,  preserve,  maintain
and defend, at its own expense,  the right, title and interest of Pledgee in and
to the Collateral and all right, title and interest  represented thereby against
all claims, charges and demands of all persons whomsoever.

                  10.5 Any  notice or other  communication  herein  required  or
permitted to be given shall be in writing and may be personally served,  telexed
or sent by  telefacsimile  or United States mail or courier service and shall be
deemed to have been given when delivered in person or by courier  service,  upon
receipt of  telefacsimile  or telex, or three (3) business days after depositing
it in the United States mail with postage  prepaid and properly  addressed.  For
the  purposes  hereof,  the address of each party hereto shall be as provided in
the Securities Purchase Agreement hereto, or at such other address as such party
may subsequently advise the other parties hereto.

                  10.6 In the event  that any  provision  of this  Agreement  is
deemed to be invalid by reason of the  operation of any law, or by reason of the
interpretation placed thereon by any court, this Agreement shall be construed as
not containing  such  provision and the  invalidity of such provision  shall not
affect  the  validity  of any  other  provision  hereof,  and any and all  other
provisions  hereof  which  otherwise  are lawful and valid shall  remain in full
force and effect.

                  10.7  This  Agreement  shall  inure  to  the  benefit  of  the
successors and assigns of Pledgee and shall be binding upon the heirs, legatees,
administrators, legal representatives, successors and assigns of Pledgor.

                  10.8  This   Agreement   may  be   executed  in  one  or  more
counterparts,  each of which shall be deemed to be an original, but all of which
taken together shall be one and the same instrument.

                  10.9 Capitalized  terms used herein and not otherwise  defined
herein shall have the meanings given to such terms in the Note.

                  10.10  This  Agreement  shall  be  governed  by the  laws  and
decisions of the State of Illinois.


                            [Signature page follows]

                                        6

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292403  v4

         IN WITNESS WHEREOF,  the parties have executed this Agreement as of the
date first above written.

                                                 PLEDGOR:

                                                 ALTAIR INTERNATIONAL, INC.

                                                 By: __________________________
                                                 Its: _________________________



         Accepted by:                            PLEDGEE:

                                                 DORAL 18, LLC


                                                 By: __________________________
                                                 Its: _________________________


         Acknowledged and Agreed:       MINERAL RECOVERY SYSTEMS,  INC.

                                                 By: __________________________
                                                 Its: _________________________


                                        7

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                                    EXHIBIT A

                                        8

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                                    EXHIBIT B

                                        9