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                                                                    EXHIBIT 2.10

                            STOCK PURCHASE AGREEMENT

        This Stock Purchase Agreement (this "Agreement") is made effective as of
February 1, 2002, by Allis-Chalmers Corporation, a Delaware corporation
("Buyer"), Energy Spectrum Partners, LP, a Delaware limited partnership
("Seller") and Strata Directional Technology, Inc., a Texas corporation (the
"Company").

                                    RECITALS

        The Company has 16,765,716 issued and outstanding shares of common
stock, of which Seller owns 14,541,413 of such shares of common stock (the
shares owned by Seller being referred to as the "Common Shares"). Seller also
owns 20,796,875 issued and outstanding shares of 9% Cumulative Convertible
Preferred Stock, Series C of the Company (the "Preferred Shares", and
collectively with the Common Shares, the "Shares").

        Seller desires to sell, and Buyer desires to purchase, all of the issued
and outstanding Common Shares of the Company owned by Seller, and all of the
issued and outstanding Preferred Shares that are outstanding as of the Closing,
for the consideration and on the terms set forth in this Agreement.

                                    AGREEMENT

        Now, therefore, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties, intending to be
legally bound, agree as follows:

1.      DEFINITIONS.

        For purposes of this Agreement, the following terms have the meanings
specified or referred to in this Section 1:

        "BREACH" -- a "Breach" of a representation, warranty, covenant,
        obligation, or other provision of this Agreement or any instrument
        delivered pursuant to this Agreement will be deemed to have occurred if
        there is or has been (a) any inaccuracy in or breach of, or any failure
        to perform or comply with, such representation, warranty, covenant,
        obligation, or other provision, or (b) any claim (by any Person) or
        other occurrence or circumstance that is or was inconsistent with such
        representation, warranty, covenant, obligation, or other provision, and
        the term "Breach" means any such inaccuracy, breach, failure, claim,
        occurrence, or circumstance.

        "BUYER" -- as defined in the first paragraph of this Agreement.

        "BUYER BALANCE SHEET" -- as defined in Section 4.4.

        "BUYER SHARES" -- as defined in Section 2.2(a).

        "CLOSING" -- as defined in Section 2.4.

        "CLOSING DATE" -- the date and time as of which the Closing actually
        takes place


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        which shall be the date of this Agreement, as provided in Section 2.4.

        "COMMON SHARES" -- as defined in the Recitals to this Agreement.

        "COMPANY" -- as defined in the first paragraph of this Agreement.

        "CONSENT" -- any approval, consent, ratification, waiver, or other
        authorization (including any Governmental Authorization).

        "CONTRACT"--any agreement, contract, obligation, promise, or undertaking
        (whether written or oral and whether express or implied) that is legally
        binding.

        "DAMAGES" -- as defined in Section 5.2.

        "ENCUMBRANCE" -- any charge, claim, community property interest,
        condition, equitable interest, lien, option, pledge, security interest,
        right of first refusal, or restriction of any kind, including any
        restriction on use, voting, transfer, receipt of income, or exercise of
        any other attribute of ownership, but excluding restrictions arising
        under state and federal securities laws.

        "GAAP" -- generally accepted United States accounting principles,
        applied on a consistent basis.

        "GOVERNMENTAL AUTHORIZATION" -- any approval, consent, license, permit,
        waiver, or other authorization issued, granted, given, or otherwise made
        available by or under the authority of any Governmental Body or pursuant
        to any Legal Requirement.

        "GOVERNMENTAL BODY" -- any nation, state, county, city, town, village,
        district, or other jurisdiction of any nature; federal, state, local,
        municipal, foreign, or other government; governmental or
        quasi-governmental authority of any nature (including any governmental
        agency, branch, department, official, or entity and any court or other
        tribunal); multi-national organization or body; or body exercising, or
        entitled to exercise, any administrative, executive, judicial,
        legislative, police, regulatory, or taxing authority or power of any
        nature.

        "LEGAL REQUIREMENT" -- any federal, state, local, municipal, foreign,
        international, multinational, or other administrative order,
        constitution, law, ordinance, principle of common law, regulation,
        statute, or treaty.

        "ORDER" -- any award, decision, injunction, judgment, order, ruling,
        subpoena, or verdict entered, issued, made, or rendered by any court,
        administrative agency, or other Governmental Body or by any arbitrator.

        "ORGANIZATIONAL DOCUMENTS" -- the articles or certificate of
        incorporation and the bylaws of a corporation and any amendments
        thereto.

        "PERSON" -- any individual, corporation (including any non-profit
        corporation),


                                                                          Page 2

<PAGE>

        general or limited partnership, limited liability company, joint
        venture, estate, trust, association, organization, labor union, or other
        entity or Governmental Body.

        "PREFERRED SHARES" -- as defined in the Recitals of this Agreement.

        "PROCEEDING" -- any action, arbitration, audit, hearing, investigation,
        litigation, or suit (whether civil, criminal, administrative,
        investigative, or informal) commenced, brought, conducted, or heard by
        or before, or otherwise involving, any Governmental Body or arbitrator.

        "PURCHASE PRICE" -- as defined in Section 2.2(a).

        "REGISTRATION RIGHTS AGREEMENT" -- as defined in Section 2.3.

        "SECURITIES ACT" -- the Securities Act of 1933 or any successor law, and
        regulations and rules issued pursuant to that Act or any successor law.

        "SELLER" -- as defined in the first paragraph of this Agreement.

        "SHARES" -- as defined in the Recitals of this Agreement.

2.      SALE AND TRANSFER OF SHARES; OTHER TRANSACTIONS; CLOSING.

        2.1. SHARES. Subject to the terms and conditions of this Agreement, at
the Closing, Seller will sell and transfer the Shares to Buyer, and Buyer will
purchase the Shares from Seller, free and clear of all Encumbrances.

        2.2. PURCHASE PRICE.

        (a) The purchase price (the "Purchase Price") for all of the Shares will
be 6,559,863 shares of Buyer's common stock, $.15 par value per share ("Buyer
Common Stock") and 3,500,000 shares of Series A 10% Cumulative Convertible
Preferred Stock, $.01 par value, of Buyer, in the form of designation attached
as Exhibit B hereto ("Buyer Preferred Stock", collectively with the Buyer Common
Stock, the "Buyer Shares").

        (b) In addition, at the Closing, Buyer shall issue to Seller a warrant
in the form attached hereto as Exhibit C permitting Seller to purchase 437,500
shares of Buyer Common Stock at an exercise price of $ .15 per share (the
"Warrant"). In the event all of the outstanding shares of the Buyer Preferred
Stock, except one, shall not have been redeemed by the Buyer on or before the
first anniversary of the Closing, Buyer shall issue to Seller a warrant
substantially in the form attached as Exhibit C hereto to purchase an additional
875,000 shares of Buyer Common Stock at an exercise price of $.15 per share.

        2.3. REGISTRATION RIGHTS. At the Closing, Seller and Buyer will enter
into a Registration Rights Agreement in the form attached hereto as Exhibit D
(the "Registration Rights Agreement"), pursuant to which Seller will be granted
demand and piggyback registration rights as described therein.


                                                                          Page 3

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        2.4. CLOSING. Consummation of the purchase by Buyer of the Shares as
contemplated herein (the "Closing") is taking place on the date of this
Agreement (the "Closing Date").

        2.5. CLOSING OBLIGATIONS. At the Closing:

        (a) Seller is delivering or causing to be delivered to Buyer:

               (i) certificates representing the Shares, duly indorsed (or
accompanied by duly executed stock powers), for transfer to Buyer;

               (ii) the Registration Rights Agreement; and

               (iii) a legal opinion of counsel to Seller in form acceptable to
Buyer.

        (b) Buyer is delivering or will cause to be delivered to Seller:

               (i) certificates representing the Buyer Shares issuable to Seller
in the name of Seller;

               (ii) the Warrant;

               (iii) the Registration Rights Agreement; and

               (iv) a legal opinion of counsel to Buyer in form acceptable to
Seller.

3.      REPRESENTATIONS AND WARRANTIES OF SELLER.

        Seller hereby represents and warrants to Buyer as of the Closing Date as
follows:

        3.1. ORGANIZATION AND GOOD STANDING. The Company is a corporation duly
incorporated, validly existing, and in good standing under the laws of the State
of Texas, with full corporate power and authority to conduct its business as it
is now being conducted and to own or use the properties and assets that it
purports to own or use. Seller and the Company have delivered or made available
to Buyer copies of the Organizational Documents of the Company as currently in
effect.

        3.2. AUTHORITY; NO CONFLICT.

        (a) This Agreement constitutes the legal, valid, and binding obligation
of Seller, enforceable against Seller in accordance with its terms, except as
may be limited by applicable bankruptcy laws or general principles of equity.
Seller has all corporate right, power, authority, and capacity to execute and
deliver this Agreement and to perform its obligations under this Agreement.

        (b) Neither the execution and delivery of this Agreement nor the
consummation or performance of any of the transactions contemplated herein will,
directly or indirectly (with or without notice or lapse of time):


                                                                          Page 4

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               (i) contravene, conflict with, or result in a violation of (1)
any provision of the Organizational Documents of the Company or Seller, or (2)
any resolution adopted by the partners of the Seller or the Board of Directors
or shareholders of the Company;

               (ii) contravene, conflict with, or result in a violation of, or
give any Governmental Body or other Person the right to challenge any of the
transactions contemplated herein or to exercise any remedy or obtain any relief
under, any Legal Requirement or any Order to which the Company or Seller, or any
of the assets owned or used by the Company, may be subject;

               (iii) contravene, conflict with, or result in a violation of any
of the terms or requirements of, or give any Governmental Body the right to
revoke, withdraw, suspend, cancel, terminate, or modify, any Governmental
Authorization that is held by the Company or that otherwise relates to the
business of, or any of the assets owned or used by, the Company;

               (iv) contravene, conflict with, or result in a violation or
breach of any provision of, or give any Person the right to declare a default or
exercise any remedy under, or to accelerate the maturity or performance of, or
to cancel, terminate, or modify, any Contract to which the Company is a party;
or

               (v) result in the imposition or creation of any Encumbrance upon
or with respect to any of the assets owned or used by the Company.

        (c) Neither Seller or the Company is or will be required to give any
notice to or obtain any Consent from any person in connection with the execution
and delivery of this Agreement or the consummation or performance of any of the
transactions contemplated herein, except as have been obtained.

        (d) Seller is acquiring the Buyer Shares for its own account and not
with a view to their distribution within the meaning of Section 2(11) of the
Securities Act.

        3.3. CAPITALIZATION. The authorized equity securities of the Company
consist of 70,000,000 Shares of common stock, $0.01 par value per share, of
which 16,765,716 Shares are issued and outstanding and 30,000,000 Shares of
preferred stock, $.10 par value per share, of which only the Preferred Shares
are issued and outstanding. All of the outstanding equity securities of the
Company have been duly authorized and validly issued and are fully paid and
nonassessable. All options to acquire any shares of common stock or preferred
stock of the Company have been terminated by the holders thereof and the
Company. Seller is the record and beneficial owner and holder of the Shares,
free and clear of all Encumbrances. None of the Shares were issued in violation
of the Securities Act or any other Legal Requirement. Schedule 3.3 lists all of
the holders of the shares of the Company's Common Stock, together with the
number of shares owned by each holder. Except for the Company's offer to redeem
shares of Common Stock at $.10 per share, there are no Contracts relating to the
issuance, sale, conversion or transfer of any equity securities or other
securities of the Company. Except for shares of Production Well Testers, Inc.,
the Company does not own, or have any Contract to acquire, any equity,
securities, or other securities of any Person or any direct or indirect equity
or ownership interest in any other business.


                                                                          Page 5

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        3.4. BROKERS OR FINDERS. Neither the Company nor Seller nor any of their
respective officers and agents have incurred any obligation or liability,
contingent or otherwise, for brokerage or finders' fees or agents' commissions
or other similar payment in connection with this Agreement.

        3.5. BOOKS AND RECORDS. The books of account, minute books, stock record
books, and other records of the Company, all of which have been made available
to Buyer, are complete and correct and have been maintained in accordance with
sound business practices. The minute books of the Company contain accurate and
complete records of all meetings held of, and corporate action taken by, the
shareholders, the Boards of Directors, and committees of the Boards of Directors
of the Company, and no meeting of any such shareholders, Board of Directors, or
committee has been held for which minutes have not been prepared and are not
contained in such minute books. At the Closing, all of those books and records
will be in the possession of the Company.

        3.6. FINANCIAL STATEMENTS; NO UNDISCLOSED LIABILITIES. Seller has
delivered to Buyer: (a) an audited balance sheet of the Company as at December
31, 2000 (including the notes thereto, the "Company Balance Sheet"), and the
related statement of income for the fiscal year then ended, and (b) an unaudited
balance sheet of the Company as at November 30, 2001, (the "Interim Company
Balance Sheet") and the related unaudited statement of income for the eleven
(11) months then ended. Such financial statements and notes fairly present the
financial condition and the results of operations of the Company as at the
respective dates of and for the periods referred to in such financial
statements, all in accordance with GAAP, subject, in the case of interim
financial statements, to normal recurring year-end adjustments (the effect of
which will not, individually or in the aggregate, be materially adverse) and the
absence of notes; the financial statements referred to in this Section 3.6
reflect the consistent application of such accounting principles throughout the
periods involved. As of the date of the Interim Company Balance Sheet and except
as set forth on the Interim Company Balance Sheet, the Company did not have any
liabilities required by GAAP to be disclosed on the Interim Company Balance
Sheet.

        3.7. ACCREDITED INVESTOR. Seller is an "accredited investor" within the
meaning of Regulation D of the Securities Act of 1933, as amended.

4.      REPRESENTATIONS AND WARRANTIES OF BUYER.

        Buyer hereby represents and warrants to Seller as of the Closing Date as
follows:

        4.1. ORGANIZATION AND GOOD STANDING. Buyer is a corporation duly
organized, validly existing, and in good standing under the laws of the State of
Delaware, with full corporate power and authority to conduct its business as it
is now being conducted and, to own or use the properties and assets that it
purports to own or use.


                                                                          Page 6

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        4.2. AUTHORITY; NO CONFLICT.

        (a) This Agreement constitutes the legal, valid, and binding obligation
of Buyer, enforceable against Buyer in accordance with its terms, except as may
be limited by applicable bankruptcy laws or general principles of equity. Buyer
has the absolute and unrestricted right, power, and authority to execute and
deliver this Agreement and to perform its obligations under this Agreement.

        (b) Neither the execution and delivery of this Agreement nor the
consummation or performance of any of the transactions contemplated herein will,
directly or indirectly (with or without notice or lapse of time):

               (i) contravene, conflict with, or result in a violation of (1)
any provision of the Organizational Documents of Buyer, or (2) any resolution
adopted by the board of directors or the shareholders of Buyer;

               (ii) contravene, conflict with, or result in a violation of, or
give any Governmental Body or other Person the right to challenge any of the
transactions contemplated herein or to exercise any remedy or obtain any relief
under, any Legal Requirement or any Order to which Buyer, or any of the assets
owned or used by Buyer, may be subject;

               (iii) contravene, conflict with, or result in a violation of any
of the terms or requirements of, or give any Governmental Body the right to
revoke, withdraw, suspend, cancel, terminate, or modify, any Governmental
Authorization that is held by Buyer or that otherwise relates to the business
of, or any of the assets owned or used by, Buyer;

               (iv) contravene, conflict with, or result in a violation or
breach of any provision of, or give any Person the right to declare a default or
exercise any remedy under, or to accelerate the maturity or performance of, or
to cancel, terminate, or modify, any Contract to which Buyer is a party; or

               (v) result in the imposition or creation of any Encumbrance upon
or with respect to any of the assets owned or used by Buyer.

        (c) Buyer was not required to give any notice to or obtain any Consent
from in connection with the execution and delivery of this Agreement or the
consummation or performance of any of the transactions contemplated herein.

        (d) Buyer is acquiring the Shares for its own account and not with a
view to their distribution within the meaning of Section 2(11) of the Securities
Act. Buyer is an "accredited investor" as such term is defined in Rule 501(a)
under the Securities Act.

        4.3. CAPITALIZATION. The authorized equity securities of Buyer consist
of 100,000,000 shares of common stock, $0.15 par value per share, of which
11,588,128 shares are issued and outstanding (prior to issuances contemplated by
Schedule 4.3) and 10,000,000 shares of preferred stock, of which 3,500,000
shares of Buyer Preferred Stock will be issued and outstanding following the
consummation of this Agreement. All of the Buyer Shares have been duly
authorized and, when


                                                                          Page 7

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issued in connection with the transactions contemplated herein, will be validly
issued and fully paid and nonassessable. Set forth on Schedule 4.3, is a list of
all Contracts relating to the issuance, sale, conversion or transfer of any
equity securities or other securities of the Buyer, including option and warrant
agreements entered into by Buyer.

        4.4. FINANCIAL STATEMENTS; SEC DOCUMENTS. Buyer has delivered to Seller:
(a) an audited balance sheet of Buyer as at December 31, 2000 (including the
notes thereto, the "Buyer Balance Sheet"), and the related statements of income
and retained earnings and cash flows for the fiscal year then ended, together
with the report thereon of PricewaterhouseCoopers LLP, independent certified
public accountants, and (b) an unaudited balance sheet of Buyer as at September
30, 2001, and the related unaudited consolidated statements of income, and
retained earnings and cash flows for the nine (9) months then ended. Such
financial statements and notes fairly present the financial condition and the
results of operations, changes in stockholders' equity, and cash flows of Buyer
as at the respective dates of and for the periods referred to in such financial
statements, all in accordance with GAAP, subject, in the case of interim
financial statements, to normal recurring year-end adjustments (the effect of
which will not, individually or in the aggregate, be materially adverse) and the
absence of notes (that, if presented, would not differ materially from those
included in the Buyer Balance Sheet); the financial statements referred to in
this Section 4.4 reflect the consistent application of such accounting
principles throughout the periods involved. Buyer has filed all documents
required to be filed by it with the Securities and Exchange Commission. As of
their respective filing dates, all of such documents complied in all material
respects with all applicable legal requirements, and none of such documents
contained any untrue statement of a material fact or omitted to state a material
fact required to be stated therein or necessary to make the statements made
therein, in light of the circumstances in which they were made, not misleading
except to the extent corrected by a subsequently filed document.

        4.5. BROKERS OR FINDERS. Buyer and its officers and agents have incurred
no obligation or liability, contingent or otherwise, for brokerage or finders'
fees or agents' commissions or other similar payment in connection with this
Agreement.

5.      INDEMNIFICATION; REMEDIES.

        5.1. SURVIVAL. All representations, warranties, covenants, and
obligations in this Agreement, the schedules hereto and any other certificate or
document delivered pursuant to this Agreement will survive the Closing for a
period of one year.

        5.2. INDEMNIFICATION AND PAYMENT OF DAMAGES BY SELLER. Seller will
indemnify and hold harmless Buyer, the Company, and their respective
Representatives, stockholders, controlling persons, and affiliates
(collectively, the "Indemnified Persons") for, and will pay to the Indemnified
Persons the amount of, any loss, liability, claim, damage (including incidental
and consequential damages), expense (including costs of investigation and
defense and reasonable attorneys' fees) or diminution of value, whether or not
involving a third-party claim (collectively, "Damages"), arising from (a) any
Breach of any representation or warranty made by Seller in this Agreement, the
schedules hereto or any other certificate or document delivered by Seller
pursuant to this Agreement; (b) any Breach by Seller or the Company of any
covenant or obligation of Seller or the Company in this Agreement; or (c) any
claim by any Person for brokerage or finder's fees or commissions or


                                                                          Page 8

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similar payments based upon any agreement made by any such Person with Seller or
the Company (or any Person acting on their behalf) in connection with any of the
transactions contemplated herein.

        The remedies provided in this Section 5.2 will be the sole remedy
available to Buyer and the Other Indemnified Persons.

        5.3. INDEMNIFICATION AND PAYMENT OF DAMAGES BY BUYER. Buyer will
indemnify and hold harmless Seller and its Representatives, stockholders,
controlling persons, and affiliates, and will pay to such Persons the amount of
any Damages arising from (a) any Breach of any representation or warranty made
by Buyer in this Agreement or in any Schedule or certificate delivered by Buyer
pursuant to this Agreement, (b) any Breach by Buyer of any covenant or
obligation of Buyer in this Agreement, or (c) any valid claim by any Person for
brokerage or finder's fees or commissions or similar payments based upon any
agreement made by such Person with Buyer (or any Person acting on its behalf) in
connection with any of the transactions contemplated herein.

        5.4. PROCEDURE FOR INDEMNIFICATION -- THIRD PARTY CLAIMS.

        (a) Promptly after receipt by an indemnified party under Section 5.2 or
Section 5.3 of notice of the commencement of any Proceeding against it, such
indemnified party will, if a claim is to be made against an indemnifying party
under such Section, give notice to the indemnifying party of the commencement of
such claim, but the failure to notify the indemnifying party will not relieve
the indemnifying party of any liability that it may have to any indemnified
party, except to the extent that the indemnifying party demonstrates that the
defense of such action is prejudiced by the indemnifying party's failure to give
such notice.

        (b) If any Proceeding referred to in Section 5.4(a) is brought against
an indemnified party and it gives notice to the indemnifying party of the
commencement of such Proceeding, the indemnifying party will, unless the claim
involves taxes, be entitled to participate in such Proceeding and, to the extent
that it wishes (unless (i) the indemnifying party is also a party to such
Proceeding and the indemnified party determines in good faith that joint
representation would be inappropriate, or (ii) the indemnifying party fails to
provide reasonable assurance to the indemnified party of its financial capacity
to defend such Proceeding and provide indemnification with respect to such
Proceeding), to assume the defense of such Proceeding with counsel satisfactory
to the indemnified party and, after notice from the indemnifying party to the
indemnified party of its election to assume the defense of such Proceeding, the
indemnifying party will not, as long as it diligently conducts such defense, be
liable to the indemnified party under this Section 5.4 for any fees of other
counsel or any other expenses with respect to the defense of such Proceeding, in
each case subsequently incurred by the indemnified party in connection with the
defense of such Proceeding, other than reasonable costs of investigation. If the
indemnifying party assumes the defense of a Proceeding; (i) it will be
conclusively established for purposes of this Agreement that the claims made in
that Proceeding are within the scope of and subject to indemnification; (ii) no
compromise or settlement of such claims may be effected by the indemnifying
party without the indemnified party's consent unless (1) there is no finding or
admission of any violation of Legal Requirements or any violation of the rights
of any Person and no effect on any other claims that may be made against the


                                                                          Page 9

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indemnified party, and (2) the sole relief provided is monetary damages that are
paid in full by the indemnifying party; and (3) the indemnified party will have
no liability with respect to any compromise or settlement of such claims
effected without its consent. If notice is given to an indemnifying party of the
commencement of any Proceeding and the indemnifying party does not, within ten
days after the indemnified party's notice is given, give notice to the
indemnified party of its election to assume the defense of such Proceeding, the
indemnifying party will be bound by any determination made in such Proceeding or
any compromise or settlement effected by the indemnified party.

        (c) Notwithstanding the foregoing, if an indemnified party determines in
good faith that there is a reasonable probability that a Proceeding may
adversely affect it or its affiliates other than as a result of monetary damages
for which it would be entitled to indemnification under this Agreement, the
indemnified party may, by notice to the indemnifying party, assume the exclusive
right to defend, compromise, or settle such Proceeding, but the indemnifying
party will not be bound by any determination of a Proceeding so defended or any
compromise or settlement effected without its consent (which may not be
unreasonably withheld).

        (d) Seller hereby consents to the non-exclusive jurisdiction of any
court in which a Proceeding is brought against any Indemnified Person for
purposes of any claim that an Indemnified Person may have under this Agreement
with respect to such Proceeding on the matters alleged therein, and agree that
process may be served on Seller with respect to such claim anywhere in the
world.

        5.5. PROCEDURE FOR INDEMNIFICATION -- OTHER CLAIMS. A claim for
indemnification for any matter not involving a third-party claim may be asserted
by notice to the party from whom indemnification is sought.

        5.6. LIMITATIONS ON AMOUNTS FOR DAMAGES. Seller shall be entitled to
satisfy and pay the entirety of any Damages to Buyer with respect to any matters
described in Section 5.2, by the delivery to Buyer of that number of Buyer
Shares having a value equal to the amount of such Damages. For the purposes of
this Section 5.6, the Buyer Shares will be valued at the average closing price
of Buyer Common Stock during the ten trading days immediately preceding the
Closing, as such term is defined in Section 2.5. The total aggregate liability
of Seller to Buyer for Damages under this Agreement shall be limited, under all
circumstances, to the aggregate value of the Buyer Shares delivered to Seller
pursuant to Section 2.2(a), as such value is calculated in accordance with this
Section 5.6. The total aggregate liability of Buyer to Seller shall be limited
to the aggregate value of the Buyer Shares delivered to Seller pursuant to
Section 2.2(a), as such value is calculated in accordance with this Section 5.6.

6.      GENERAL PROVISIONS.

        6.1. EXPENSES. Except as otherwise expressly provided in this Agreement,
each party to this Agreement will bear its respective expenses incurred in
connection with the preparation, execution, and performance of this Agreement
and the transactions contemplated herein, including all fees and expenses of
agents, representatives, counsel, and accountants. In the event the Closing
occurs, Buyer will bear all legal and other expenses with respect to the
transaction contemplated herein, including the fees and expenses of counsel
representing Seller and the Company. In the


                                                                         Page 10

<PAGE>

event of termination of this Agreement, the obligation of each party to pay its
own expenses will be subject to any rights of such party arising from a Breach
of this Agreement by another party.

        6.2. PUBLIC ANNOUNCEMENTS. Any public announcement or similar publicity
with respect to this Agreement or the transactions contemplated herein will be
issued, if at all, at such time and in such manner as the parties shall mutually
determine. Seller, the Company and Buyer will consult with each other concerning
the means by which the Company' employees, customers, and suppliers and others
having dealings with the Company will be informed of the transactions
contemplated herein, and Buyer will have the right to be present for any such
communication.

        6.3. NOTICES. All notices, consents, waivers, and other communications
under this Agreement must be in writing and will be deemed to have been duly
given when (a) delivered by hand (with written confirmation of receipt), (b)
sent by telecopier (with written confirmation of receipt), provided that a copy
is mailed by registered mail, return receipt requested, or (c) when received by
the addressee, if sent by a nationally recognized overnight delivery service
(receipt requested), in each case to the appropriate addresses and telecopier
numbers set forth below (or to such other addresses and telecopier numbers as a
party may designate by notice to the other parties):

               SELLER:       Thomas O. Whitener, Jr.
                             Energy Spectrum Partners, LP
                             5956 Sherry Lane, Suite 900
                             Dallas, Texas  75225
                             Facsimile:  (214) 987-6110

               copy to:      Frank P. McEachern
                             Jackson Walker L.L.P.
                             901 Main Street, Suite 6000
                             Dallas, Texas 75202
                             Facsimile:  (214) 953-5822

               BUYER:        Allis-Chalmers Corporation
                             1875 Century Park East, Suite 600
                             Century City, California  90067
                             Facsimile:  (310) 407-5499

               copy to:      Theodore F. Pound III
                             Wilson, Cribbs, Goren & Flaum, P.C.
                             440 Louisiana, Suite 2200
                             Houston, Texas 77002
                             Facsimile:  (713) 228-8824

        6.4. JURISDICTION; SERVICE OF PROCESS. Any action or Proceeding seeking
to enforce any provision of, or based on any right arising out of, this
Agreement may be brought against any of the parties in the courts of the State
of Texas, Counties of Dallas or Harris, or, if it has or can acquire
jurisdiction, in the United States District Court for the Northern or Southern
District of Texas, and each of the parties consents to the jurisdiction of such
courts (and of the appropriate appellate courts)


                                                                         Page 11

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in any such action or Proceeding and waives any objection to venue laid therein.
Process in any action or Proceeding referred to in the preceding sentence may be
served on any party anywhere in the world.

        6.5. FURTHER ASSURANCES. The parties agree (a) to furnish upon request
to each other such further information, (b) to execute and deliver to each other
such other documents, and (c) to do such other acts and things, all as the other
party may reasonably request for the purpose of carrying out the intent of this
Agreement and the documents referred to in this Agreement.

        6.6. WAIVER. The rights and remedies of the parties to this Agreement
are cumulative and not alternative. Neither the failure nor any delay by any
party in exercising any right, power, or privilege under this Agreement or the
documents referred to in this Agreement will operate as a waiver of such right,
power, or privilege, and no single or partial exercise of any such right, power,
or privilege will preclude any other or further exercise of such right, power,
or privilege or the exercise of any other right, power, or privilege. To the
maximum extent permitted by applicable law, (a) no claim or right arising out of
this Agreement or the documents referred to in this Agreement can be discharged
by one party, in whole or in part, by a waiver or renunciation of the claim or
right unless in writing signed by the other party; (b) no waiver that may be
given by a party will be applicable except in the specific instance for which it
is given; and (c) no notice to or demand on one party will be deemed to be a
waiver of any obligation of such party or of the right of the party giving such
notice or demand to take further action without notice or demand as provided in
this Agreement or the documents referred to in this Agreement.

        6.7. ENTIRE AGREEMENT AND MODIFICATION. This Agreement supersedes all
prior agreements between the parties with respect to its subject matter
(including the Letter of Intent between Buyer, the Company and Seller dated July
25, 2001, as amended) and constitutes (along with the documents referred to in
this Agreement) a complete and exclusive statement of the terms of the agreement
between the parties with respect to its subject matter. This Agreement may not
be amended except by a written agreement executed by the party to be charged
with the amendment.

        6.8. ASSIGNMENTS, SUCCESSORS, AND NO THIRD-PARTY RIGHTS. Neither party
may assign any of its rights under this Agreement without the prior consent of
the other parties. Subject to the preceding sentence, this Agreement will apply
to, be binding in all respects upon, and inure to the benefit of the successors
and permitted assigns of the parties. Nothing expressed or referred to in this
Agreement will be construed to give any Person other than the parties to this
Agreement any legal or equitable right, remedy, or claim under or with respect
to this Agreement or any provision of this Agreement. This Agreement and all of
its provisions and conditions are for the sole and exclusive benefit of the
parties to this Agreement and their successors and assigns.

        6.9. SEVERABILITY. If any provision of this Agreement is held invalid or
unenforceable by any court of competent jurisdiction, the other provisions of
this Agreement will remain in full force and effect. Any provision of this
Agreement held invalid or unenforceable only in part or degree will remain in
full force and effect to the extent not held invalid or unenforceable.

        6.10. SECTION HEADINGS, CONSTRUCTION. The headings of Sections in this
Agreement are provided for convenience only and will not affect its construction
or interpretation. All references to "Section" or "Sections" refer to the
corresponding Section or Sections of this Agreement. All


                                                                         Page 12

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words used in this Agreement will be construed to be of such gender or number as
the circumstances require. Unless otherwise expressly provided, the word
"including" does not limit the preceding words or terms.

        6.11. TIME OF ESSENCE. With regard to all dates and time periods set
forth or referred to in this Agreement, time is of the essence.

        6.12. GOVERNING LAW. This Agreement will be governed by the laws of the
State of Texas without regard to conflicts of laws principles.

        6.13. COUNTERPARTS. This Agreement may be executed in one or more
counterparts, each of which will be deemed to be an original copy of this
Agreement and all of which, when taken together, will be deemed to constitute
one and the same agreement.

        6.14. CONFIDENTIALITY. Each party shall keep all documents and other
information obtained from the other party in confidence, subject to the valid
requirements of any governmental or other authorities, and except with respect
to information that is readily ascertainable from public or public information
or trade sources. If the transaction contemplated herein is not consummated, all
such confidential information will be promptly returned to the party furnishing
it.

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                                                                         Page 13

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

                             BUYER:

                             ALLIS-CHALMERS CORPORATION

                             By:    /s/ Munawar H. Hidayatallah
                                    --------------------------------------
                                    Munawar H. Hidayatallah
                             Its:   Chairman and Chief Executive Officer


                             SELLER:

                             ENERGY SPECTRUM PARTNERS, LP

                             By: Energy Spectrum Capital LP, General Partner

                                    By:     Energy Spectrum LLC, General Partner


                                            By:    /s/ Thomas O. Whitener, Jr.
                                                   -----------------------------
                                                   Thomas O. Whitener, Jr.
                                            Its:   Chief Operating Officer


                             THE COMPANY:

                             STRATA DIRECTIONAL TECHNOLOGY, INC.


                             By:    /s/ Stanley J. Buffington
                                    --------------------------------------
                                    Stanley J. Buffington
                             Its:   President



                                                                    Schedule 3.3