LOCK-UP AGREEMENT

April 3, 1998

Boe & Company
3668 So. Jasper ST.
Aurora, CO 80013

     Re: Summa Metals Corp.

Gentlemen:

The undersigned is the owner ("Record  Owner") of 1,050,000 shares of the common
stock of Summa  Metals  Corp.  (the  "Company"),  par value $.001 per share (the
"Shares"),  which  shares are  evidenced by  certificate  Number(s)  000125.  In
consideration of the Company's filing a Registration Statement on Form SB-2 with
the Securities and Exchange  Commission,  the undersigned hereby agrees with the
Company and Boe & Company (the "Underwriter")  among the other things enumerated
below,  not to sell the  Shares  or  otherwise  transfer  the  Shares  except as
provided herein,  until the expiration of the "lock-up" period described in Item
4, Below. The Undersigned further agrees that the restriction on the transfer of
the Shares relates to the certificate  referenced  above or the ownership of the
Shares by any transferee of the Shares who acquired same by operation of law. In
connection with the foregoing, the undersigned agrees as follows:

1.   The Record Owner has full power and authority to enter into this  Agreement
     and to restrict  the  transferability  and  salability  of the  Shares,  as
     provided herein.

2.   The  Record  Owner's  compliance  with the  terms  and  conditions  of this
     Agreement will not conflict with any instrument or agreement  pertaining to
     such  Shares,  and will not  conflict  with,  result  in a  breach  of,  or
     constitute a default  under any  instrument  to which the Record Owner is a
     party.

3.   The Record  Owner owns the Shares  free anmd clear of any and all liens and
     encumbrances.

4.   Neither  the  Record  Owner  nor  the  heirs,  representatives,  executors,
     administrators,  successors  or assigns of the Record  Holder,  will offer,
     sell, pledge or otherwise dispose of any of the Shares publicly without the
     prior written consent of the Underwriter for a period of twelve months from
     the effective date of the public offering of the Company's Shares.

5.   The Record  Owner  agrees not to make any  private  transfer  of the Shares
     unless the transferee  agrees in writing to be bound by the restrictions of
     paragraph 4 hereof.


    Sincerely,

/s/ Michael Chaffee
    --------------------------
    Michael Chaffee