<PAGE>

                       INCENTIVE STOCK OPTION AGREEMENT
                                    (PLAN)

          THIS AGREEMENT is made as of the 30th day of April, 1996,

BETWEEN:

         SUMMO MINERALS CORPORATION, a company duly incorporated under the laws
         of the Province of British Columbia, having its registered office at 
         860-625 Howe Street, Vancouver, B.C., V6C 2T6

         (hereinafter called the "Company")

                                                              OF THE FIRST PART

AND:

         MATTHEW J. MASON, of 860-625 Howe St.
         ----------------     -------------------------------------------------
         Vancouver, BC V6C 2T6
         ----------------------------------------------------------------------
         (RESIDENTIAL ADDRESS, INCLUDING POSTAL (ZIP) CODE)

         (hereinafter called the "Optionee")

                                                             OF THE SECOND PART.

    WHEREAS:

A.  the Optionee is a director of the Company and requires as a condition of
holding such position that the parties enter into this Incentive Stock Option
Agreement on the terms and conditions hereinafter set forth;

B.  this incentive stock option is granted by the Company in reliance on the
exemptions from registration and prospectus requirements contained in Sections
31(2)(10) and 55(2)(9) of the SECURITIES ACT (British Columbia) and Sections
35(1)(19) and 72(1)(n) of the SECURITIES ACT (Ontario);

C.  the Company has been classified as a "Resource" company by the Vancouver
Stock Exchange and as a "Non-Exempt" resource company by The Toronto Stock
Exchange;

D.  the directors of the Company passed a resolution at their board meeting held
January 15, 1996 implementing an Incentive Stock Option Plan (the "PLAN"),
subject to shareholder ratification, a copy of which is attached hereto as
"Schedule "A";

E.  the option herein granted is subject to the terms and conditions of the 
Plan;


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                                       3

8.   This agreement may be executed in several parts in the same form and such
parts as so executed will together constitute one original agreement, and such
parts, if more than one, will be read together as if all the signing parties
hereto had executed one copy of this agreement.

9.   This agreement shall enure to the benefit of and be binding upon the 
parties hereto and their respective heirs, executors, administrators, and 
successors.

10.  Wherever the plural or masculine are used throughout this agreement, the 
same shall be construed as meaning singular or feminine or neuter or the body 
politic where the context of the parties thereto require.

11.  The Optionee hereby acknowledges and confirms that he has obtained 
independent legal advice with respect to this agreement and understands and 
is aware that the securities of the Company have not been registered under 
the Securities Act of 1933, as amended. The Optionee covenants with and to 
the Company that he will exercise the option herein granted, and dispose of 
the shares thereby acquired, only in accordance with all applicable laws.

12.  In this agreement, all references to money are references to Canadian 
dollars.

     IN WITNESS WHEREOF the parties have hereunto caused these presents to be
executed as of the day and year first above written.

The COMMON SEAL of                )
SUMMO MINERALS                    )
CORPORATION                       )
in the presence of:               )
                                  )
[illegible]                       )
-----------------------------     )    c/s 
Authorized signatory              )

SIGNED, SEALED AND DELIVERED      ) 
by MATTHEW J. MASON               ) 
in the presence of:               )
[illegible]                       )    /s/ Matthew J. Mason
-----------------------------     )    ------------------------------------
Witness                                Matthew J. Mason


This is page 3 to that certain Incentive Stock Option Agreement between SUMMO
MINERALS CORPORATION and MATTHEW J. MASON dated as of the 30th day of April,
1996.

<PAGE>


                                 Schedule "A"
--------------------------------------------------------------------------------

                         SUMMO MINERALS CORPORATION
                    EMPLOYEE INCENTIVE STOCK OPTION PLAN

1.  PURPOSE

    The purpose of the Employee Incentive Stock Option Plan (the "Plan") is 
to promote the profitability and growth of SUMMO MINERALS CORPORATION 
("Summo") by facilitating the efforts of Summo and its subsidiaries to obtain 
and retain key individuals. The Plan provides an incentive for and encourages 
ownership of Summo's shares by its key individual so that they may increase 
their stake in Summo and benefit from increases in the value of Summo's 
shares.

2.  ADMINISTRATION

    The Plan will be administered by a committee (the "Committee") of Summo's 
Board of Directors (the "Board"), which will consist of two or more members. 
All members of the Committee shall be non-employee directors who a 
"Disinterested Persons" with regard to Plan administration, within the 
meaning of Rule 16b-3 as promulgated and amended from time to time by the 
United States Securities and Exchange Commission.

    The Committee will be authorized, subject to the provisions of the Plan, 
to adopt such rules and regulations which it deems consistent with the Plan's 
provisions and, in its sole discretion, to designate options ("Options") to 
purchase shares of Summo pursuant to the Plan. The Committee may authorize 
one or more individuals of Summo to execute, deliver and receive documents on 
behalf of the Committee.

3.  ELIGIBILITY

    All directors and officers and employees of Summo and its subsidiaries 
will be eligible to receive Options. The term "subsidiaries" for the purpose 
of the Plan will include Summo U.S.A. Corporation, which definition may be 
varied by the Committee to conform with the changing interests of Summo.

    Nothing in the Plan or in any option shall confer any right on any 
individual to continue in the employ of or association with Summo or its 
subsidiaries or will interfere in any way with the right of Summo or 
subsidiaries to terminate at any time the employment of a person who is an 
optionee ("Optionee") under an Option.

4.  SHARES SUBJECT TO OPTION

    The shares to be optioned under the Plan will be authorized but unissued 
Common Shares without par value ("Shares") of Summo.

     At no time will more than 2,000,000 Shares be under option either 
pursuant to the Plan or pursuant to other incentive stock options issued by 
Summo. The number of Shares under option at any specific time to any one 
Optionee shall not exceed 5% of the issued and outstanding common share 
capital of Summo, subject to adjustment under Section 12 below.

    Shares subject to and not delivered under an Option which expires or 
terminates shall again be available for option under the Plan. The maximum 
number of Shares which may be issued pursuant to

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                                       2

the Plan shall not however exceed 2,000,000 Shares.

5.  GRANTING OF OPTIONS

    The Committee may from time to time at its discretion, subject to the 
provisions of the Plan, determine those eligible individuals to whom Options 
will be granted, the number of Shares subject to such Options, the dates on 
which such Options are to be granted and the expiration of such Options.

    The Committee may, at its discretion, with respect to any Option, impose 
additional terms and conditions which are more restrictive on the optionee 
than those provided for in the Plan.

    Each Option will be evidenced by a written agreement between, and 
executed by, Summo and the individual containing such terms and conditions 
established by the Committee with respect to such Option and will be 
consistent with the provisions of the Plan.

    Options shall be granted to directors only according to the following 
formula:

      (i)  Each director who was a member of the Board of Directors prior to 
           January 1, 1996, shall upon adoption of this Plan be issued 
           Options for that number of Shares necessary to bring the aggregate 
           number of Shares underlying incentive options issued to such 
           director to 150,000 Shares. The exercise price of such Options 
           shall be determined as provided in Section 6 hereof.

     (ii)  Each director who becomes a member of the Board of Directors after 
           January 1, 1996, shall be granted Options for 50,000 Shares upon 
           his or her election or appointment to the Board. The exercise 
           price shall be determined as provided in Section 6 hereof.

    (iii)  Upon the expiration date of any Options issued to a director 
           (regardless of whether such Options were exercised on or prior to 
           the expiration date), such director shall be issued Options for an 
           additional 50,000 Shares. The exercise price shall be determined 
           as provided in Section 6 hereof. The provisions of this paragraph 
           (iii) shall also apply upon the expiration date of any other 
           incentive stock options issued to a director if at the time of 
           such expiration date, the director holds incentive options, 
           including Options, for fewer than an aggregate of 50,000 Shares 
           underlying such options, in which case the director shall be 
           issued that number of Options necessary to bring the aggregate 
           number of Shares underlying incentive options issued to such 
           director at such time to 50,000 Shares. The calculation of 
           incentive options held by any director shall not include any 
           warrants to purchase Summo shares held by a director provided such 
           warrants were issued by Summo in connection with securities 
           offered by Summo.

     (iv)  The foregoing formulas shall not be amended more than once every 
           six months other than to comport with changes in the Internal 
           Revenue Code, the Employee Retirement Income Security Act, or the 
           rules thereunder.

      (v)  Additional options may be granted to directors at the discretion 
           of the Committee,

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                                       3

           provided that no director may receive additional options while 
           serving on the Committee if the receipt of such options would 
           cause him to cease to be a Disinterested Person.

6.  OPTION PRICE

    The price per Share at which Shares may be purchased upon the exercise of 
an Option (the "Option Price") will not be lower that the "market price" of 
the Shares on The Toronto Stock Exchange (the "TSE") at the time of grant. In 
the context of the Plan, "market price" means the closing price of Summo's 
shares on the TSE at the close of trading which immediately preceded the time 
that the option was granted. If the shares of Summo do not trade on such day, 
the "market price" shall be the average of the bid and ask prices on the 
previous trading day.

7.  TERM OF OPTION

    The maximum term of any Option will be 10 years.

    The Option Price will be paid in full at the time of exercise of the 
Option and no Shares will be delivered until full payment is made.

    An Optionee will not be deemed the holder of the Shares subject to his 
Option until the Shares are delivered to him.

8.  TRANSFERABILITY OF OPTIONS

    An Option may not be assigned. During the lifetime of an Optionee, the 
Option may be exercised only by the Optionee.

9.  TERMINATION OF EMPLOYMENT

Upon termination of employment for any reason except death or retirement or 
failure of re-election as a director or failure to be re-appointed an 
officer of Summo, an Optionee may, at any time within 30 days after the date 
of termination but not later than the date of expiration of the Option, 
exercise the Option to the extent the Optionee was entitled to do so on the 
date of termination. Any option or portions of Options of terminated 
individuals not so exercised will terminate and again be available for future 
Options under the Plan. A change of employment will not be considered a 
termination so long as the Optionee continues to be employed by Summo or its 
subsidiaries.

10. DEATH

    Notwithstanding any other provision of this Plan other than the maximum 
of 10 years provided for in Section 7, if any Optionee shall die holding an 
Option which has not been fully exercised, his personal representative, heirs 
or legatees may, at any time within 60 days of grant of probate of the will 
or letters of administration of the estate of the decedent or within one year 
after the date of such death, whichever is the lesser time, exercise the 
Option with respect to the unexercised balance of the Shares subject to the 
Option.


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                                       4

11. RETIREMENT

    Notwithstanding any other provision of this Plan, if any Optionee shall 
retire or terminate his employment with the consent of the Board under 
circumstances equating retirement, while holding an Option which has not been 
fully exercised, such Optionee may exercise the Option at any time during the 
unexpired term of the Option.

12. CHANGE IN SHARES

    In the event the authorized common share capital of Summo as presently 
constituted is consolidated into a lesser number of Shares or subdivided into 
a greater number of Shares, the number of Shares for which Options are 
outstanding will be decreased or increased proportionately as the case may be 
and the Option Price will be adjusted accordingly and the Optionee will have 
the benefit of any stock dividend declared during the period within which the 
said Optionee held his Option. Should Summo amalgamate or merge with any 
other Company or companies (the right to do so being expressly reserved) 
whether by way of arrangement, sale of assets and undertakings or otherwise, 
then and in each such case the number of shares of the resulting corporation 
to which an Option relates will be determined as if the Option has been fully 
exercised prior to the effective date of the amalgamation or merger and the 
Option Price will be correspondingly increased or decreased, as applicable.

13. CANCELLATION AND RE-GRANTING OF OPTIONS

    The Committee may, with the consent of the Optionee, cancel any existing 
Option, and re-grant the Option at an Option Price determined in the same 
manner as provided in Section 6 hereof, subject to the prior approval of the 
TSE.

14. AMENDMENT OR DISCONTINUANCE

    The Board may alter, suspend or discontinue the Plan, but may not, 
without the approval of the shareholders of Summo and the TSE, may any 
alteration which would (a) increase the aggregate number of Shares subject to 
Option under the Plan except as provided in Section 12 or (b) decrease the 
Option Price except as provided in Section 12. Notwithstanding the foregoing, 
the terms of an existing Option may not be altered, suspended or discontinued 
without the consent in writing of the Optionee.

15. INTERPRETATION

    The Plan will be construed according to the laws of the Province of 
British Columbia,

16. LIABILITY

    No member of the Committee or any director, officer or employee of Summo 
will be personally liable for any act taken or omitted in good faith in 
connection with the Plan.