<PAGE>
                               CERTIFICATE OF AMENDMENT

                                          OF

                             CERTIFICATE OF INCORPORATION

                                          OF

                                     REFRACO INC.

It is hereby certified that:

          1.   The name of the Corporation is Refraco Inc.

          2.   The Certificate of Incorporation of the Corporation is hereby
amended by striking out Article FOURTH thereof and by substituting in lieu of
said Article the following new Article:

          FOURTH.   (1)       The Corporation is authorized to issue three
classes of shares designated, respectively, "Common Stock," "Class B Common
Stock" and "Preferred Stock."  The aggregate number of shares of capital stock
which the Corporation is authorized to issue is One Million (1,000,000) shares,
consisting of  Five Hundred Thousand (500,000) shares of Common Stock, $.01 par
value, One Hundred Thousand (100,000) shares of Class B Common Stock, $.01 par
value, and Four Hundred Thousand (400,000) shares of Preferred Stock, $.01 par
value.

          (2)       The Board of Directors is expressly authorized to provide
for the issue of all or any shares of the Preferred Stock in one or more series,
and to fix the number of shares and to determine or alter, for each such series,
such powers, designations, voting rights, if any, preferences and relative,
participating, optional or other rights and such qualifications, limitations or
restrictions thereof, as shall be stated and expressed in the resolution or
resolutions adopted by the Board of Directors providing for the issue of such
series (a "Preferred Stock Designation") and as may be permitted by the General
Corporation Law of the State of Delaware.  The Board of Directors is also
expressly authorized to increase or decrease (but not below the number of shares
of any such series then outstanding) the number of shares of any series
subsequent to the issue of shares of that series.  In case the number of shares
of any such series shall be so decreased, the shares constituting such decrease
shall resume the status which they had prior to the adoption of the Preferred
Stock Designation originally fixing the number of shares of such series.  The
number of authorized shares of Preferred Stock may be increased or decreased
(but not below the number of shares thereof then outstanding) by the affirmative
vote of the holders of a majority of the voting power of all of the then
outstanding shares of the capital stock of the Corporation entitled to vote,
voting together as a single class, without a separate vote of the holders of the
Preferred Stock, or any series thereof, unless a vote of any such holders is
required pursuant to any Preferred Stock Designation.


<PAGE>


          (3)  Except as set forth in this Article FOURTH, the shares of  Common
Stock and Class B Common Stock shall be identical in all respects.  Without
limiting the foregoing,

          (a)  If the Corporation shall subdivide either class of common stock
     into a greater number of shares of such class, the shares of the other
     class of common stock shall be subdivided, by the same factor, into a
     greater number of shares of such class.  If the Corporation shall combine
     shares of either class of common stock into a lesser number of shares of
     such class, the shares of the other class of common stock shall be
     combined, by the same factor, into a lesser number of shares of such class.


          (b)  If the Corporation shall declare, or fix a record date for the
     determination of holders of either class of common stock entitled to
     receive, a dividend or other distribution, then and in each such event
     provision shall be made so that the holders of each class of common stock
     shall receive in such dividend or distribution the same amount and types of
     cash, property, securities, or other consideration per share as is received
     by the holders of the other class.

          (c)  If at any time or from time to time there shall be a capital
     reorganization of the common stock (other than a subdivision or combination
     described in clause 3(a) above) or a merger or consolidation of the
     Corporation with or into another corporation, or the sale of all or
     substantially all of the Corporation's properties and assets to any other
     person, then, as a part of such reorganization, merger, consolidation, or
     sale, provision shall be made so that the holders of the shares of Class B
     Common Stock shall be entitled to receive, with respect to each such share,
     the number or amount, and the kind, of shares of stock or other securities,
     property, or other consideration of the Corporation, or of the successor
     corporation resulting from such merger or consolidation or sale, which a
     holder of a share of Common Stock is entitled to receive pursuant to such
     capital reorganization, merger, consolidation or sale.  In addition, the
     Certificate of Incorporation or other governing documents of any successor
     corporation resulting from such merger or consolidation or (if, in
     connection with a sale, the Corporation liquidates or the holders of the
     Class B Common Stock receive securities of such successor corporation and,
     in either case, under the terms of Section 4 of this Article FOURTH, the
     Put Right (as defined below) would otherwise not terminate on or
     immediately after the consummation of any such transaction) sale shall
     contain provisions which preserve as nearly as practicable the  rights of
     the holders of the Class B Common Stock set forth in Section 4 of this
     Article FOURTH.  The protections afforded to the Class B Common Stock by
     the provisions of this Section 3(c) of this Article FOURTH shall apply to
     successive reorganizations, mergers, consolidations, and sales.

     (4)(a)    On and subject to the terms and conditions of this Article
FOURTH, each person (each, an "Initial Holder") who becomes a holder of  Class B
Common Stock on the date on which Class B Common Stock is first issued (the
"Initial Issuance Date") and each Permitted Transferee (as defined below; the
Initial Holders and Permitted Transferees are sometimes referred to herein as a
"Holder" or "Holders") shall have the right and option (the "Put Right"),

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exercisable during the Exercise Period (as defined below), to require the
Corporation to purchase from such Holder all, but not less than all, of its or
his respective Class B Common Stock Units  (as defined below) for a purchase
price (the "Put Price") equal to (i) $2,077 per unit (the "Base Put Price") plus
(ii) an amount, if any, in the nature of interest on the aggregate Base Put
Price, calculated at a rate of 8% per annum, compounded annually, from the third
anniversary of the Initial Issuance Date to the date the Put Price is paid.
"Class B Common Stock Unit" shall mean (i) one share of Class B Common Stock and
(ii) all cash (other than regular cash dividends), property, securities, and
other consideration, if any, received with respect to such share as a result of
dividends, distributions, capital reorganizations, mergers, consolidations, or
sales of all or substantially all of the assets (collectively, the "Other
Consideration"). 

     (b)  A Holder shall exercise the Put Right by giving notice (a "Put
Notice"), at any time during the Exercise Period, by first class mail, postage
prepaid.  Each Put Notice shall be accompanied by the certificates for the
shares of Class B Common Stock held by the Holder giving such Put Notice,
properly endorsed or accompanied by stock powers properly endorsed for transfer,
and appropriate transfer documents with respect to the Other Consideration held
by the Holder giving such Put Notice, and shall state (i) the election of the
Holder to exercise the Put Right and (ii) the number of Class B Common Stock
Units owned by such Holder.  Within five days after receipt of a Put Notice in
proper form, the Corporation shall pay the Put Price by certified or bank check
or wire transfer in accordance with instructions received from the Holder.  Upon
payment of the Put Price, the shares of Class B Common Stock so repurchased by
the Corporation shall no longer be deemed to be outstanding, all rights of the
holders thereof as stockholders of the Corporation shall cease, and the
Corporation shall thereupon cancel the certificates representing those shares. 

     (c)(i)    On each of the second through fifth anniversaries of the Initial
Issuance Date, the Corporation will cause to be issued for the benefit of the
Holders a standby letter of credit (a "Letter of Credit") in a face amount (or
cause the face amount of a previously issued Letter of Credit to be increased)
such that the aggregate face amount of the Letters of Credit outstanding during
the year (or, with respect to the fifth anniversary, during the 180 days)
commencing on such anniversary date is equal to the respective percentage set
forth below of the aggregate Base Put Price that would be payable by the
Corporation if the Put Right were then exercised as to all outstanding Class B
Common Stock Units:

<TABLE>
                  Anniversary           Percentage
                  -----------           ----------
<S>               <C>                   <C>
                    2                        15
                    3                        30
                    4                        45
                    5                        60
</TABLE>

     (ii)  Each Letter of Credit shall provide that (A) it shall be renewed
annually so that the Letter of Credit issued on the fifth anniversary of the
Initial Issuance Date expires not earlier than 180 days after the fifth
anniversary of the Initial Issuance Date, (B) it may not be revoked or 


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its amount reduced (except as set forth in Section 4(c)(iii)) without the
unanimous consent of the Holders of the Class B Common Stock, and (C) the issuer
of the Letter of Credit shall pay to any Holder, within the LC Payment Period
(as defined below), the amount of the Put Price (or the allocated portion
thereof as provided in Section 4(c)(iv)) for the Class B Common Stock Units held
by such Holder upon presentation by such Holder of a request for payment
certifying that (I) the Corporation has failed to pay any or a specified portion
of the Put Price within the five day period provided in Section 4(b) or
(II) pursuant to the Guarantee by The Alpine Group Inc. ("Alpine") relating to
the performance by the Corporation of the Corporation's obligations hereunder as
the same may be amended from time to time (the "Guarantee"), Alpine has failed
to pay any or a specified portion of the Put Price within the five day period
provided in Section 4(b) or as required upon proper exercise of the Accelerated
Put Right under (and as defined in) the Guarantee, and in each case accompanied
by a copy of such Holder's Put Notice.  Each Letter of Credit shall be issued by
a commercial bank or other financial institution domiciled in the United States
having a combined capital and surplus or net worth of at least $500 million. 
The "LC Payment Period" shall mean, for any request for payment made (x) within
30 days of the first such request made within any Exercise Period, the period
commencing 31 days after, and ending 35 days after, the date of such first
request for payment, and (y) after such 30 day period, the period ending five
days after such request for payment.

     (iii) Upon expiration or termination of the Put Right for any reason,
the Corporation may cancel or revoke all outstanding Letters of Credit.  The
Corporation may at any time replace a Letter of Credit with a substitute Letter
of Credit.  If at any time the aggregate face amount of the Letters of Credit
then outstanding is greater than the amount required to be outstanding under
Section 4(c)(i), the Corporation shall be entitled to reduce the face amount of
the Letters of Credit to the required amount.


     (iv)  If and to the extent the Corporation or Alpine fails to pay the Put
Price upon proper exercise of the Put Right or the Accelerated Put Right by a
Holder or Holders, such Holder or Holders shall be entitled to draw upon the
Letters of Credit.  If, within 30 days of the first request for payment under
the Letters of Credit with respect to an Exercise Period, more than one Holder
has made a request for payment under the Letters of Credit, and the aggregate
face amount of the Letters of Credit is not sufficient to fully satisfy the
unpaid portion of the Corporation's or Alpine's obligation to pay the Put Price
payable to all such Holders (the "Requesting Holders"), the proceeds of the
Letters of Credit shall be allocated (A) first, to the Requesting Holder or
Requesting Holders who have received the lowest amount per Class B Common Stock
Unit, until such Requesting Holder or Requesting Holders have received the
amount per unit paid to the Requesting Holder or Requesting Holders who have
received the second lowest amount per unit or the proceeds of the Letters of
Credit are exhausted, (B) then to the Requesting Holder or Requesting Holders
who have received the second lowest amount per unit, and the Requesting Holder
or Requesting Holders who have received the lowest amount per Class B Common
Stock Unit, until such Requesting Holder or Requesting Holders have received the
amount per unit paid to the Requesting Holder or Requesting Holders who have
received the third lowest amount per unit or the proceeds of the Letters of
Credit are exhausted, (C) successively, in the same fashion, until all
Requesting Holders have received the same 

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<PAGE>

amount per unit or the proceeds of the Letters of Credit are exhausted, and
(D) finally, among all Requesting Holders (or, if the proceeds of the Letters of
Credit are exhausted before all Requesting Holders have received the same amount
per unit, then among the last group of Requesting Holders who are entitled to an
allocation under (A), (B), or (C) of this Section 4(c)(iv)), pro rata among such
Requesting Holders based on the respective amounts of the aggregate Put Price
payable to each such Requesting Holder.

     (d)  The "Exercise Period" shall mean, for all or that class of Holders
specified below, the 180-day period following the earliest to occur with respect
to such Holders of any of the following events:

          (i)   for all Holders, the fifth anniversary of the Initial Issuance
     Date; or

          (ii) for the Holders who are members of a Qualifying Group (as defined
     below) which has given the Corporation notice (the "Acceleration Notice")
     of the occurrence of a Default (as defined below), the date on which such
     Acceleration Notice is given.

               (A)  "Qualifying Group" means (I) Minerals Trading, Inc., a
          Delaware corporation ("MTI"), together with the Permitted Transferees
          of MTI, or (II) the Initial Holders other than MTI, together with the
          Permitted Transferees of such Initial Holders.  Each Qualifying Group
          shall give an Acceleration Notice only if authorized by vote or
          written consent of the Holders owning a majority of the shares of
          Class B Common Stock then owned by all members of such Qualifying
          Group in the aggregate (it being understood that each member of a
          Qualifying Group which becomes entitled to exercise the Put Right
          shall be entitled and required to separately exercise or not exercise
          such Put Right, and that either or both of the Qualifying Groups may
          give an Acceleration Notice).

               (B)  A "Default" shall have occurred if any lender to the
          Corporation or any trustee under any of its credit agreements or
          indentures with respect to borrowed money shall have declared the
          principal amount thereunder to be due and payable prior to scheduled
          maturity.

     (e)(i)    The Put Right with respect to any Class B Common Stock Unit shall
terminate upon (A) the expiration of the Exercise Period during which the Put
Right becomes actually exercisable with respect to such Unit, provided that the
Corporation has not defaulted in its obligations with respect to the exercise of
the Put Right, (B) the sale, assignment, transfer, or other disposition, direct
or indirect, of the share of Class B Common Stock included in such Unit, except
for the sale, assignment, transfer, or other disposition to any Permitted
Transferee (and provided, that a pledge of or other encumbrance on a share of
Class B Common Stock shall not be deemed a disposition unless and until such
pledge or other encumbrance is levied upon and results in the actual transfer of
beneficial ownership of such share), (C) the expiration of the exercise period
during which the Accelerated Put Right becomes actually exercisable with 

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respect to such Unit under the Guarantee, provided that Alpine has not defaulted
in its obligations with respect to the exercise of the Accelerated Put Right, or
(D) the Fair Market Value (as defined below) of a Class B Common Stock Unit
exceeding 115% of the Put Price for each of 20 trading days contained in a
period of 30 consecutive trading days (the "30-Day Period") commencing after the
latest of (I) the listing of the Common Stock on a national securities exchange
or the Nasdaq National Market, (II) 33 months after the Initial Issuance Date,
and (III) the expiration of any lock-up period to which the Holder agrees in
connection with a public offering by the Corporation, provided that in the case
of clause (D), the Put Right with respect to any Class B Common Stock Unit shall
terminate only if the securities included in such Class B Common Stock Unit are
freely-tradable by the Holder during the 30-Day Period and thereafter (it being
understood with respect to clauses (A) and (C) that neither the Put Right nor
the Accelerated Put Right shall terminate or be deemed to have been waived if a
Qualifying Group shall have a right to accelerate the Put Right or to obtain the
Accelerated Put Right but does not exercise such right).  "Fair Market Value" on
any day shall mean (A) for Class B Common Stock, the closing price on such day
of one share of Common Stock on a national securities exchange or the Nasdaq
National Market and (B) for any Other Consideration, the fair market value on
such day of such Other Consideration as determined by a nationally recognized
investment banking firm with which the Corporation and its affiliates have had
no prior relationship and which shall be selected by the Corporation.

     (ii) Upon the expiration or earlier termination of the Put Right with
respect to any  Class B Common Stock Unit, or at any other time upon the
election of the holder of such Class B Common Stock Unit, the share of Class B
Common Stock included in such unit shall be converted, without any further
action, into one share of Common Stock.  The holder of any certificate
representing shares of Class B Common Stock so converted shall, promptly upon
the request of the Corporation, deliver such certificates to the Corporation for
cancellation, and the Corporation shall promptly issue to such holder a new
certificate representing the corresponding number of shares of Common Stock;
provided, that the failure of the Corporation to request such delivery, or such
holder to make such delivery, shall not affect the conversion, which shall be
effective upon the date of expiration of termination as provided in the first
sentence of this Section 4(e)(ii).

     (iii) The term "Permitted Transferee" shall mean

           (A)  the spouse or issue of a Holder or a trust of which there are no
     principal beneficiaries other than Holders and spouses and issue of
     Holders;

           (B)  the estate or heirs of a Holder upon the death of the Holder;

           (C)  a legal representative of a Holder in the event such Holder
     becomes mentally incompetent;

           (D)  another Holder; or



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<PAGE>

           (E)  the ultimate parent corporation (a "Parent") of a Holder that 
     is a corporation or any wholly-owned direct or indirect subsidiary of 
     such Parent (a "Controlled Subsidiary"), provided that upon the 
     subsequent sale, liquidation or spin-off of such Controlled Subsidiary 
     or other transaction in which the Parent ceases to control, directly or 
     indirectly, 100% of the equity of the Controlled Subsidiary the Put 
     Right shall immediately terminate with respect to any Class B Common 
     Stock Units held by such Controlled Subsidiary.
     
     (f)  The Corporation shall deliver to each Holder:

          (i)  As soon as available but no later than 120 days after the end of
     each fiscal year, a balance sheet of the Corporation and its subsidiaries
     as of the end of such year, together with the related statements of
     operations, stockholders' equity, and cash flow for the Corporation for
     such fiscal year, on a consolidated basis.  Such financial statements shall
     be in reasonable detail with appropriate notes and be prepared in
     accordance with generally accepted accounting principles consistently
     applied from year to year.  The annual financial statements shall be
     audited by the independent public accountants then regularly employed by
     the Corporation.

          (ii) As soon as available but no later than 60 calendar days after the
     end of each of the first three fiscal quarters of each fiscal year, a
     balance sheet of the Corporation and its subsidiaries and related
     statements of operations, stockholders' equity, and cash flow for such
     quarterly period and for the period from the beginning of such fiscal year
     to the end of such fiscal quarter, certified by the chief financial officer
     or controller of the Corporation as having been prepared in accordance with
     generally accepted accounting principles consistently applied (subject to
     changes resulting from audits and year-end adjustments).

          (iii)     Together with each delivery of financial statements pursuant
     to Section 4(f)(i) or (ii), a certificate of the chief financial officer of
     the Corporation that no Default or Refraco Default (as defined in the
     Guarantee) has occurred and is continuing or, if any Default or Refraco
     Default has occurred and is continuing, a description thereof in reasonable
     detail and of the action the Corporation has taken or proposes to take with
     respect thereto.

          (iv) Promptly after the Chief Financial Officer of the Corporation
     shall obtain knowledge of the occurrence of any Default or Refraco Default,
     a notice specifying that such notice is a "Notice of Default" and
     describing such Default or Refraco Default in reasonable detail and, in
     such Notice of Default or as soon thereafter as practicable, a description
     of the action the Corporation has taken or proposes to take with respect
     thereto.

     (g)  If the Corporation (i) subdivides outstanding shares of Class B Common
Stock into a greater number of shares or (ii) combines outstanding shares of
Class B Common Stock 

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into a smaller number of shares, then the Put Price in effect immediately prior
to such action shall be adjusted so that the aggregate Put Price that would be
payable to the Holders upon exercise of the Put Right immediately after such
action is equal to the aggregate Put Price that would have been payable to the
Holders upon exercise of the Put Right immediately prior to such action.  The
adjustment shall become effective immediately after the effective date of the
subdivision or combination.  Whenever the Put Price is adjusted, the Corporation
shall calculate the adjustment to be made and shall promptly mail to the Holders
a notice of the adjustment briefly stating the facts requiring the adjustment
and the manner of computing it.

     (h)  If, at the time the Corporation is required to purchase Class B Common
Stock Units pursuant to this Section 4, its surplus is legally insufficient for
the Corporation to make the portion of the payment attributable to the purchase
of the Class B Common Stock (or other securities of the Corporation) included in
such Units, the entire available surplus shall be applied to the payment, and
the Corporation shall promptly take all such action as may be permitted by law
(including any reduction in the par value of any of its shares) to reduce the
capital of the Corporation or to revalue its assets to the greatest extent
permitted by law so as to increase its surplus to the extent necessary to permit
the Corporation to purchase all shares it is required to purchase or, if that is
not legally permissible, as many of such shares as possible.

     (i)  All certificates for the shares of Class B Common Stock shall bear the
following legend:

          THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE BEEN
          ISSUED WITHOUT REGISTRATION UNDER THE SECURITIES ACT OF
          1933, AS AMENDED (THE "SECURITIES ACT"), OR QUALIFICATION
          UNDER THE BLUE SKY LAWS OF ANY JURISDICTION.  SUCH
          SECURITIES MAY NOT BE SOLD, ASSIGNED, TRANSFERRED OR
          OTHERWISE DISPOSED OF, BENEFICIALLY OR ON THE RECORDS OF THE
          CORPORATION, UNLESS THE SECURITIES REPRESENTED BY THIS
          CERTIFICATE HAVE BEEN REGISTERED UNDER THE SECURITIES ACT
          AND QUALIFIED UNDER APPLICABLE BLUE SKY LAWS OR AN EXEMPTION
          FROM SUCH REGISTRATION AND QUALIFICATION IS AVAILABLE.

The certificates evidencing such shares shall also bear any legends required
pursuant to any state, local or foreign law governing such securities.

     (5)  Shares of Class B Common Stock which are acquired by the Corporation,
whether by exercise of the Put Right or otherwise, or which are converted into
Common Stock, shall be retired and not reissued.


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     (6)  Sections 3, 4, 5, and this Section 6 of this Article FOURTH may be
amended, any of the obligations of the Corporation therein may be waived, and
additional shares of Class B Common Stock may be issued after the Initial
Issuance Date, only with the unanimous consent of the holders of the Class B
Common Stock. 

          3.   The amendment of the Certificate of Incorporation herein
certified has been duly adopted and written consent has been given in accordance
with the provisions of Sections 228 and 242 of the General Corporation Law of
the State of Delaware.

Dated:  January 30, 1998

                                   REFRACO INC.



                                   By: /s/ Bragi F. Schut
                                       --------------------------------
                                       Name:  Bragi F. Schut
                                       Title:  Executive Vice President