<PAGE>

================================================================================

               UNITED STATES SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549


                                   FORM 10-Q\A
(Mark One)

[X]  QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE
     ACT OF 1934 FOR THE QUARTERLY PERIOD ENDED SEPTEMBER 30, 1999 OR

[_]  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES
     EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM _________ TO _________


                        Commission file number 1-10389
                                               -------



                          WESTERN GAS RESOURCES, INC.
--------------------------------------------------------------------------------
             (Exact name of registrant as specified in its charter)


              Delaware                                        84-1127613
-------------------------------------                  -------------------------
   (State or other jurisdiction of                         (I.R.S. Employer
    incorporation or organization)                        Identification No.)

12200 N. Pecos Street, Denver, Colorado                        80234-3439
--------------------------------------------------------------------------------
(Address of principal executive offices)                       (Zip Code)

                                (303) 452-5603
--------------------------------------------------------------------------------
              Registrant's telephone number, including area code

                                  No Changes
--------------------------------------------------------------------------------
  (Former name, former address and former fiscal year, if changed since last
                                   report).



Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days.  Yes    X    No  _____
                                         -----


On November 1, 1999, there were 32,152,731 shares of the registrant"s Common
Stock outstanding.

This form 10-Q/A for the quarterly period ended September 30, 1999 is being
filed to correct an inaccurate subtotal on the Consolidated Statement of Cash
Flows (unaudited) appearing on page 4 of Item 1. Financial Statements
(unaudited). The line entitled "Net cash provided by (used in) operating
activities" for the nine months ended September 30, 1998 should have totaled
$(55,288) instead of $(96,001).

This subtotal is also corrected in Item 2. Management's Discussion and Analysis
of Financial Condition and Results of Operations on page 12 in the table
comparing results of operations for the nine months ended September 30, 1999 to
the results of operations for the nine months ended September 30, 1998.
================================================================================

                                       1
<PAGE>

                          Western Gas Resources, Inc.
                                  Form 10-Q/A
                               Table of Contents


PART I - Financial Information                                              Page
------------------------------                                              ----

  Item 1.  Financial Statements (Unaudited)

           Consolidated Balance Sheet - September 30, 1999 and December
           31, 1998........................................................   3

           Consolidated Statement of Cash Flows - Nine months ended
           September 30, 1999 and 1998.....................................   4

           Consolidated Statement of Operations - Three and nine months
           ended September 30, 1999 and 1998...............................   5

           Consolidated Statement of Changes in Stockholders' Equity -
           Nine months ended September 30, 1999............................   6

           Notes to Consolidated Financial Statements......................   7

  Item 2.  Management's Discussion and Analysis of Financial Condition
           and Results of Operations.......................................  12

Signatures.................................................................  19

                                       2
<PAGE>

                        PART I - FINANCIAL INFORMATION

Item 1.  Financial Statements
         --------------------
                          WESTERN GAS RESOURCES, INC.
                          CONSOLIDATED BALANCE SHEET
                   (Dollars in thousands, except share data)
<TABLE>
<CAPTION>
                                                                                September 30,   December 31,
                                                                                     1999           1998
                                                                                --------------  -------------
  ASSETS                                                                                  (Unaudited)
  ------
<S>                                                                             <C>             <C>
Current assets:
 Cash and cash equivalents....................................................     $    5,472     $    4,400
 Trade accounts receivable, net...............................................        220,069        233,574
 Product inventory............................................................         30,031         46,207
 Parts inventory..............................................................          9,952         10,153
 Other........................................................................              -          2,951
                                                                                   ----------     ----------
  Total current assets........................................................        265,524        297,285
                                                                                   ----------     ----------
Property and equipment:
 Gas gathering, processing, storage and transmission..........................        789,353        952,531
 Oil and gas properties and equipment.........................................        153,957        111,602
 Construction in progress.....................................................         47,343         87,943
                                                                                   ----------     ----------
                                                                                      990,653      1,152,076
 Less:  Accumulated depreciation, depletion and amortization..................       (297,628)      (305,589)
                                                                                   ----------     ----------
  Total property and equipment, net...........................................        693,025        846,487
                                                                                   ----------     ----------
Other assets:
 Gas purchase contracts (net of accumulated amortization of $30,258 and
  $29,978, respectively)......................................................         37,390         41,263
 Other........................................................................         42,602         34,342
                                                                                   ----------     ----------
  Total other assets..........................................................         79,992         75,605
                                                                                   ----------     ----------
Total assets..................................................................     $1,038,541     $1,219,377
                                                                                   ==========     ==========
  LIABILITIES AND STOCKHOLDERS' EQUITY
  ------------------------------------
Current liabilities:
 Accounts payable.............................................................     $  244,253     $  245,315
 Accrued expenses.............................................................         26,979         31,727
 Dividends payable............................................................          4,217          4,217
                                                                                   ----------     ----------
   Total current liabilities..................................................        275,449        281,259

Long-term debt................................................................        214,333        504,881
Senior subordinated debt......................................................        155,000              -
Deferred income taxes payable.................................................         38,816         48,021
                                                                                   ----------     ----------
   Total liabilities..........................................................        683,598        834,161
                                                                                   ----------     ----------
Commitments and contingent liabilities........................................              -              -

Stockholders' equity:
 Preferred stock, par value $.10; 10,000,000 shares authorized:
  $2.28 cumulative preferred stock; 1,400,000 shares issued and outstanding
   ($35,000,000 aggregate liquidation preference).............................            140            140
  $2.625 cumulative convertible preferred stock; 2,760,000 shares issued and
   outstanding ($138,000,000 aggregate liquidation preference)................            276            276
 Common stock, par value $.10; 100,000,000 shares authorized; 32,177,247 and
   32,173,009 shares issued and outstanding, respectively.....................          3,218          3,217
 Treasury stock, at cost, 25,016 shares.......................................           (788)          (788)
 Additional paid-in capital...................................................        397,397        397,344
 Accumulated deficit..........................................................        (45,605)       (17,075)
 Accumulated other comprehensive income.......................................          1,189          3,053
 Notes receivable from key employees secured by common stock..................           (884)          (951)
                                                                                   ----------     ----------
   Total stockholders' equity.................................................        354,943        385,216
                                                                                   ----------     ----------
Total liabilities and stockholders' equity....................................     $1,038,541     $1,219,377
                                                                                   ==========     ==========
</TABLE>

   The accompanying notes are an integral part of the consolidated financial
                                  statements.

                                       3
<PAGE>

                          WESTERN GAS RESOURCES, INC.
                     CONSOLIDATED STATEMENT OF CASH FLOWS
                                  (Unaudited)
                            (Dollars in thousands)
<TABLE>
<CAPTION>
                                                                                                  Nine Months Ended
                                                                                                     September 30,
                                                                                              -------------------------
                                                                                                 1999          1998
                                                                                              -----------   -----------
<S>                                                                                           <C>           <C>
Reconciliation of net income to net cash (used in) provided by operating activities:
Net income............................................................................        $   (15,882)  $     5,893
Add income items that do not affect working capital:
 Depreciation, depletion and amortization.............................................             37,850        43,605
 Deferred income taxes................................................................             (9,204)        4,412
 Distributions (less than) in excess of equity income, net............................               (354)          438
 (Gain) loss on the sale of property and equipment....................................             21,406       (14,813)
 Foreign currency translation adjustments.............................................             (1,864)          214
 Other non-cash items, net............................................................                493           964
Adjustments to working capital to arrive at net cash (used in) provided by
 operating activities:
 Decrease in trade accounts receivable................................................              4,910        62,735
 Decrease in product inventory........................................................             16,176       (44,277)
 Decrease in parts inventory..........................................................                201          (896)
 Increase in other current assets.....................................................             11,546         1,854
 Decrease in other assets and liabilities, net........................................                444           143
 Decrease in accounts payable.........................................................             (1,062)     (115,237)
 Decrease in accrued expenses.........................................................             (5,085)         (323)
                                                                                              -----------   -----------
Net cash provided by (used in) operating activities...................................             59,575       (55,288)
                                                                                              -----------   -----------

Cash flows from investing activities:
 Purchase of property and equipment...................................................            (49,043)      (72,887)
 Proceeds from the dispositions of property and equipment.............................            148,100        22,600
 Contributions to equity investees....................................................               (100)         (748)
                                                                                              -----------   -----------
Net cash provided by (used in) investing activities...................................             98,957       (51,035)
                                                                                              -----------   -----------

Cash flows from financing activities:
 Net proceeds from exercise of common stock options...................................                 54            23
 Proceeds from issuance of long-term debt.............................................            155,000             -
 Debt issue costs paid................................................................             (9,319)          (45)
 Payments on revolving credit facility................................................         (2,022,000)   (2,266,350)
 Borrowings under revolving credit facility...........................................          1,815,500     2,380,350
 Payments on long-term debt...........................................................            (84,047)       (7,143)
 Dividends paid.......................................................................            (12,648)      (12,651)
                                                                                              -----------   -----------

Net cash (used in) provided by financing activities...................................           (157,460)       94,184
                                                                                              -----------   -----------
Net increase (decrease) in cash and cash equivalents..................................              1,072       (12,139)
Cash and cash equivalents at beginning of period......................................              4,400        19,777
                                                                                              -----------   -----------
Cash and cash equivalents at end of period............................................        $     5,472   $     7,638
                                                                                              ===========   ===========
</TABLE>

   The accompanying notes are an integral part of the consolidated financial
                                  statements.

                                       4
<PAGE>

                          WESTERN GAS RESOURCES, INC.
                     CONSOLIDATED STATEMENT OF OPERATIONS
                                  (Unaudited)
          (Dollars in thousands, except share and per share amounts)
<TABLE>
<CAPTION>
                                                               Three Months Ended           Nine Months Ended
                                                                  September 30,               September 30,
                                                            -------------------------   -------------------------
                                                               1999           1998          1999          1998
                                                            -----------   -----------   -----------   -----------
<S>                                                         <C>           <C>           <C>           <C>
Revenues:
 Sale of residue gas....................................    $   392,679   $   402,600   $ 1,107,734   $ 1,207,572
 Sale of natural gas liquids............................         97,660        99,947       237,514       332,571
 Processing, transportation and storage revenue.........         11,799        11,459        36,118        33,450
 Other, net.............................................          3,439         2,253       (11,844)       23,892
                                                            -----------   -----------   -----------   -----------

   Total revenues.......................................        505,577       516,259     1,369,522     1,597,485
                                                            -----------   -----------   -----------   -----------

Costs and expenses:
 Product purchases......................................        456,246       469,367     1,251,424     1,429,835
 Plant operating expense................................         17,096        22,258        50,615        62,919
 Oil and gas exploration and production expense.........          2,346         2,050         6,029         5,045
 Depreciation, depletion and amortization...............         13,095        14,277        37,850        43,605
 Selling and administrative expense.....................          5,759         6,917        21,711        21,824
 Interest expense.......................................          9,365         8,969        25,118        25,265
                                                            -----------   -----------   -----------   -----------

   Total costs and expenses.............................        503,907       523,838     1,392,747     1,588,493
                                                            -----------   -----------   -----------   -----------

Income (loss) before income taxes.......................          1,670        (7,579)      (23,225)        8,992

Provision (benefit) for income taxes:
 Current................................................           (528)        2,336           754        (1,313)
 Deferred...............................................          1,140        (5,268)       (9,204)        4,412
                                                            -----------   -----------   -----------   -----------

   Total provision (benefit) for income taxes...........            612        (2,932)       (8,450)        3,099
                                                            -----------   -----------   -----------   -----------

Income (loss) before extraordinary items................          1,058        (4,647)      (14,775)        5,893

Extraordinary charge for early extinguishment of debt,
 net of tax benefit of $700,000.........................              -             -        (1,107)            -
                                                            -----------   -----------   -----------   -----------

Net income (loss).......................................          1,058        (4,647)      (15,882)        5,893

Preferred stock requirements............................         (2,610)       (2,610)       (7,829)       (7,829)
                                                            -----------   -----------   -----------   -----------

Income (loss) attributable to common stock..............    $    (1,552)  $    (7,257)  $   (23,711)  $    (1,936)
                                                            ===========   ===========   ===========   ===========

Income (loss) per share of common stock.................          $(.05)        $(.23)        $(.74)        $(.06)
                                                            ===========   ===========   ===========   ===========

Weighted average shares of common stock outstanding.....     32,150,111    32,147,993    32,148,699    32,147,354
                                                            ===========   ===========   ===========   ===========

Income (loss) per share of common stock -
 assuming dilution......................................          $(.05)        $(.23)        $(.74)        $(.06)
                                                            ===========   ===========   ===========   ===========

Weighted average shares of common stock outstanding -
 assuming dilution......................................     32,516,287    32,147,993    32,332,631    32,148,655
                                                            ===========   ===========   ===========   ===========
</TABLE>

   The accompanying notes are an integral part of the consolidated financial
                                  statements.

                                       5
<PAGE>

                          WESTERN GAS RESOURCES, INC.
                CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY
                                  (Unaudited)
                 (Dollars in thousands, except share amounts)
<TABLE>
<CAPTION>
                                                  Shares of
                                    Shares of      $2.625                                            $2.625
                                      $2.28      Cumulative                 Shares      $2.28      Cumulative
                                    Cumulative  Convertible    Shares     Of Common   Cumulative  Convertible
                                    Preferred    Preferred   of Common      Stock     Preferred    Preferred   Common  Treasury
                                      Stock        Stock       Stock     in Treasury    Stock        Stock     Stock     Stock
                                    ----------  -----------  ----------  -----------  ----------  -----------  ------  --------
<S>                                 <C>         <C>          <C>         <C>          <C>         <C>          <C>     <C>
Balance at December 31,
 1998.............................   1,400,000   2,760,000  32,147,993       25,016  $      140  $       276  $3,217  $   (788)

Comprehensive Income:
Net loss.........................            -           -           -            -           -            -       -         -
Foreign Currency
 Translation.....................            -           -           -            -           -            -       -         -

Comprehensive Income

Dividends:
Dividends declared on common
 stock............................           -           -           -            -           -            -       -         -

Dividends declared on $2.28
 cumulative preferred stock.......           -           -           -            -           -            -       -         -

Dividends declared on $2.625
 cumulative convertible preferred
 stock............................           -           -           -            -           -            -       -         -

Loans forgiven....................           -           -           -            -           -            -       -         -
Stock Options Exercised                      -           -       4,238            -           -            -       1         -
                                    ----------  -----------  ----------  -----------  ----------  -----------  ------  --------
Balance at September 30, 1999.....   1,400,000    2,760,000  32,152,231       25,016  $      140  $       276  $3,218  $   (788)
                                    ----------  -----------  ----------  -----------  ----------  -----------  ------  --------
<CAPTION>
                                                             Accumulated
                                                                Other       Notes      Total
                                    Additional                 Compre-    Receivable   Stock-
                                     Paid-in    Accumulated    Hensive     from Key   holders'
                                     Capital      Deficit      Income     Employees    Equity
                                    ----------  -----------  -----------  ----------  --------
<S>                                 <C>         <C>          <C>          <C>         <C>
Balance at December 31,
 1998.............................  $  397,344  $   (17,075) $     3,053  $     (951) $385,216

Comprehensive Income:
Net loss.........................            -      (15,882)           -           -   (15,882)
Foreign Currency
 Translation.....................            -            -       (1,864)          -    (1,864)
                                                                                      --------
Comprehensive Income                                                                   (17,746)
                                                                                      ========
Dividends:
Dividends declared on common
 stock............................           -       (4,821)           -           -    (4,821)

Dividends declared on $2.28
 cumulative preferred stock.......           -       (2,394)           -           -    (2,394)

Dividends declared on $2.625
 cumulative convertible preferred
 stock............................           -       (5,433)           -           -    (5,433)


Loans forgiven....................           -            -            -          67        67
Stock Options Exercised                     53            -            -           -        54
                                    ----------  -----------  -----------  ----------  --------
Balance at September 30, 1999.....  $  397,397  $   (45,605) $     1,189  $     (884) $354,943
                                    ==========  ===========  ===========  ==========  ========
</TABLE>

   The accompanying notes are an integral part of the consolidated financial
                                  statements.

                                       6
<PAGE>

                          WESTERN GAS RESOURCES, INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Unaudited)

   GENERAL

The interim consolidated financial statements presented herein should be read in
conjunction with the Consolidated Financial Statements and Notes thereto
included in our Annual Report on Form 10-K for the year ended December 31, 1998.
The interim consolidated financial statements as of September 30, 1999 and for
the three and nine month periods ended September 30, 1999 and 1998 included
herein are unaudited but reflect, in the opinion of management, all adjustments
(which include only normal recurring adjustments) necessary to fairly present
the results for such periods.  The results of operations for the three and nine
months ended September 30, 1999 are not necessarily indicative of the results of
operations expected for the year ended December 31, 1999.

Certain prior year amounts in the interim consolidated financial statements and
notes have been reclassified to conform to the presentation used in 1999.

   SALE OF SENIOR SUBORDINATED DEBT

In June 1999, we sold $155.0 million of Senior Subordinated Notes in a private
placement. These notes bear interest at 10% and were priced at 99.225% to yield
10.125%. We received net proceeds of approximately $150.0 million from the
offering of these notes, after deducting underwriters' discounts and estimated
expenses of the offering. We applied a portion of the net proceeds to repay
approximately $33.3 million of outstanding indebtedness under the Master Shelf
Agreement, on which pre-tax make-whole payments of  $1.1 million were also paid.
The remaining proceeds of approximately $115.6 million were used to repay a
portion of the outstanding indebtedness under our Revolving Credit Facility.
We are in the process of making a registered Exchange Offer to the private
noteholders to exchange these privately placed notes for registered publicly
tradable notes under the same terms and conditions.

   EXTRAORDINARY ITEM - EARLY EXTINGUISHMENT OF DEBT

In addition to the $1.1 million make-whole payment incurred in connection with
the repayments under the Master Shelf Agreement, we incurred an additional
$700,000 in fees and expenses related to these prepayments as well as
prepayments of a portion of the 1995 Senior Notes and the prepayment of the 1993
Senior Notes.  The total costs incurred of approximately $1.8 million, net of a
tax benefit of $700,000, were reflected as an extraordinary loss on early
extinguishment of debt in the second quarter of 1999.  The net extraordinary
loss of $1.1 million resulted in an increase in loss per share of common stock -
assuming dilution of $.03.

   EARNINGS (LOSS) PER SHARE OF COMMON STOCK

Earnings per share of common stock is computed by dividing income attributable
to common stock by the weighted average shares of common stock outstanding.  In
addition, earnings per share of common stock - assuming dilution is computed by
dividing income attributable to common stock by the weighted average shares of
common stock outstanding as adjusted for potential common shares.  Income
attributable to common stock is income less preferred stock dividends.  We
declared preferred stock dividends of $2.6 million and $7.8 million,
respectively, for both of the three and nine month periods ended September 30,
1999 and 1998.  Common stock options, which are potential common shares, had a
dilutive effect on earnings and increased the weighted average shares of common
stock outstanding by 1,301 for the nine month periods ended September 30, 1998.
Common stock options were anti-dilutive for the three month periods ended
September 30, 1998 and 1999 and the nine month period ended September 30, 1999,
and were not included in the calculation of earnings per share. The numerators
and the denominators for the three and nine month periods ended September 30,
1999 and 1998 are not adjusted to reflect our outstanding $2.625 Cumulative
Convertible Preferred Stock.  These shares are antidilutive as the incremental
shares available upon conversion result in an increase in earnings per share or
decrease in the loss per share, after giving effect to the dividend
requirements.

                                       7
<PAGE>

   ASSET SALES

Giddings.   In April 1999, we sold our Giddings gathering system in Texas to GPM
Gas Corporation, a business unit of Phillips Petroleum Company.  This
transaction had an effective date of January 1, 1999.  The proceeds from this
sale were $36.0 million.  This sale resulted in an approximate pre-tax loss of
$6.6 million in the second quarter of 1999, subject to final accounting
adjustment.

Katy.   Effective April 30, 1999, we sold all the stock of our wholly owned
subsidiary, Western Gas Resources Storage, Inc., to the Aquila Energy
Corporation, a business unit of Utilicorp United, for gross proceeds of $100.0
million.  The sole asset of this subsidiary was the Katy Hub and Gas Storage
Facility.  This transaction resulted in an approximate pre-tax loss of $16.6
million, in the second quarter of 1999, subject to final accounting adjustments.
In April 1999, we also sold 5.1 Bcf of stored gas in the Katy facility to the
same purchaser for total sales proceeds of $11.7 million, which approximated our
cost of the inventory. To meet the needs of our marketing operations, we will
continue to contract for storage capacity. Accordingly, we entered into a long-
term agreement with the purchaser for approximately 3 Bcf of storage capacity at
market rates.

MiVida.   In June 1999, we sold our MiVida treating facility for gross proceeds
of $12.0 million.  This transaction resulted in an approximate pre-tax gain of
$1.2 million in the second quarter of 1999, subject to final accounting
adjustments.

The proceeds from all of these sales were used to reduce borrowings outstanding
under the revolving credit facility.


   SUPPLEMENTARY CASH FLOW INFORMATION

Interest paid was $21.6 million and $26.5 million, respectively, for the nine
months ended September 30, 1999 and 1998.

No income taxes were paid for the nine months ended September 30, 1999 and 1998,
respectively.



   SEGMENT REPORTING

We operate in four principal business segments, as follows: Gas Gathering and
Processing, Producing Properties, Marketing and Transmission.  These segments
are separately monitored by management for performance against its internal
forecasts and are consistent with our internal financial reporting package.
These segments have been identified based upon the differing products and
services, regulatory environment and the expertise required for these
operations.

The Gas Gathering and Processing segment connects producers' wells to its
gathering systems for delivery to its processing or treating plants, processes
the natural gas to extract NGLs and treats the natural gas in order to meet
pipeline specifications.  The residue gas and NGLs extracted at the processing
facilities are sold by the Marketing segment.

The activities of the Producing Properties segment include the exploration and
development of oil and gas producing properties in basins where our facilities
are located.  The majority of the gas and oil produced from these properties is
sold by the Marketing segment.

The Marketing segment buys and sells gas and NGLs nationwide and in Canada,
providing storage, transportation, scheduling, peaking and other services to our
customers.  In addition, this segment also markets gas and NGLs produced by our
facilities.  The gains and losses from any hedges on equity gas and NGL volumes
are included in this segments' results.  The operations associated with the Katy
Facility and the loss from the sale of this facility are included in the
Marketing segment, as are our Canadian marketing operations (which are
immaterial for separate presentation).

The Transmission segment reflects the operations of our MIGC and MGTC pipelines.
The majority of the revenue presented in this segment is derived from
transportation of residue gas.

                                       8
<PAGE>

The following table sets forth our segment information as of and for the three
and nine month periods ended September 30, 1999 and 1998 (dollars in thousands).
Due to our integrated operations, the use of allocations in the determination of
business segment information is necessary.  Intersegment revenues are valued at
prices comparable to those of unaffiliated customers.

<TABLE>
<CAPTION>
                                               Gas
                                            Gathering                                                      Elim-
                                               and       Producing                 Trans-                 inating
                                           Processing   Properties   Marketing    mission    Corporate    Entries     Total
                                           ----------   ----------   ---------    -------    ---------   ---------   --------
<S>                                        <C>          <C>          <C>          <C>        <C>         <C>         <C>
Three months ended September 30, 1999
Revenues from unaffiliated
customers..............................    $   10,231   $      (18)  $ 492,135    $ 1,706    $   1,037   $     (12)  $505,079
Interest income........................             -            -           4          -        6,114      (5,975)       143
Other, net.............................           616           24        (285)         -            -           -        355
Intersegment sales.....................       111,630        9,565      24,784      4,012            -    (149,991)         -
                                           ----------   ----------   ---------    -------    ---------   ---------   --------
Total revenues.........................       122,477        9,571     516,638      5,718        7,151    (155,978)   505,577
                                           ----------   ----------   ---------    -------    ---------   ---------   --------
Product purchases......................        81,254          551     519,456         91          (19)   (145,087)   456,246
Plant operating expense................        13,783          621         143      2,951          163        (565)    17,096
Oil and gas exploration
and production expense.................             -        2,343           -          -            3           -      2,346
                                           ----------   ----------   ---------    -------    ---------   ---------   --------
Operating margin.......................    $   27,440   $    6,056   $  (2,961)   $ 2,676    $   7,004   $ (10,326)  $ 29,889
                                           ==========   ==========   =========    =======    =========   =========   ========

Depreciation, depletion and
amortization...........................         8,198        3,284          41        324        1,180          68     13,095
Interest expense.......................                                                                                 9,365
Selling and administrative expense.....                                                                                 5,759
                                                                                                                     --------
Income before income taxes.............                                                                              $  1,670
                                                                                                                     ========

Identifiable assets....................    $  523,928   $   96,127   $      88    $67,892    $  37,252   $       -   $725,287
                                           ==========   ==========   =========    =======    =========   =========   ========

<CAPTION>

                                               Gas
                                            Gathering                                                      Elim-
                                               and       Producing                 Trans-                 inating
                                           Processing   Properties   Marketing    mission    Corporate    Entries     Total
                                           ----------   ----------   ---------    -------    ---------   ---------   --------
<S>                                        <C>          <C>          <C>          <C>        <C>         <C>         <C>
Three months ended September 30, 1998
Revenues from unaffiliated
customers..............................    $    9,987   $      593   $ 504,384    $   559    $     332   $      69   $515,924
Interest income........................             1            -           -          -        7,380      (7,204)       177
Other, net.............................           (37)           -         195          -            -           -        158
Intersegment sales.....................       103,367        4,916      17,390      2,858            -    (128,531)         -
                                           ----------   ----------   ---------    -------    ---------   ---------   --------
Total revenues.........................       113,318        5,509     521,969      3,417        7,712    (135,666)   516,259
                                           ----------   ----------   ---------    -------    ---------   ---------   --------
Product purchases......................        83,441          301     511,941         35         (635)   (125,716)   469,367
Plant operating expense................        20,646          314       1,771      2,216          129      (2,818)    22,258
Oil and gas exploration
and production expense.................             1        1,909         118          -           (1)         23      2,050
                                           ----------   ----------   ---------    -------    ---------   ---------   --------
Operating margin.......................    $    9,230   $    2,985   $   8,139    $ 1,166    $   8,219   $  (7,155)  $ 22,584
                                           ==========   ==========   =========    =======    =========   =========   ========

Depreciation, depletion and
amortization...........................         9,563        2,287       1,047        253        1,161         (34)    14,277
Interest expense.......................                                                                                 8,969
Selling and administrative expense.....                                                                                 6,917
                                                                                                                     --------
(Loss) before income taxes.............                                                                              $ (7,579)
                                                                                                                     ========

Identifiable assets....................    $  649,423   $  108,527   $ 119,735    $56,215    $  32,793   $       -   $966,693
                                           ==========   ==========   =========    =======    =========   =========   ========
</TABLE>

                                       9
<PAGE>

<TABLE>
<CAPTION>
                                               Gas
                                            Gathering                                                      Elim-
                                               and       Producing                 Trans-                 inating
                                           Processing   Properties   Marketing    mission    Corporate    Entries      Total
                                           ----------   ----------   ----------   -------    ---------   ---------   ----------
<S>                                        <C>          <C>          <C>          <C>        <C>         <C>         <C>
Nine months ended September 30, 1999
Revenues from unaffiliated
customers.............................     $   33,362   $    1,062   $1,347,586   $ 5,402    $   2,759   $     (41)  $1,390,130
Interest income.......................              1            -           28         -       19,422     (19,165)         286
Other, net............................         (4,173)          24      (16,745)        -            -           -      (20,894)
Intersegment sales....................        274,835       22,648       63,724    12,194            -    (373,401)           -
                                           ----------   ----------   ----------   -------    ---------   ---------   ----------
Total revenues........................        304,025       23,734    1,394,593    17,596       22,181    (392,607)   1,369,522
                                           ----------   ----------   ----------   -------    ---------   ---------   ----------
Product purchases.....................        209,053        1,450    1,408,636       609       (1,520)   (366,804)   1,251,424
Plant operating expense...............         38,703        1,623        1,816     8,322        2,079      (1,928)      50,615
Oil and gas exploration
and production expense................              -        5,940          (44)        -          133           -        6,029
                                           ----------   ----------   ----------   -------    ---------   ---------   ----------
Operating margin......................     $   56,269   $   14,721   $  (15,815)  $ 8,665    $  21,489   $ (23,875)  $   61,454
                                           ==========   ==========   ==========   =======    =========   =========   ==========

Depreciation, depletion and
amortization..........................         23,830        8,553        1,250       844        3,373           -       37,850
Interest expense......................                                                                                   25,118
Selling and administrative expense....                                                                                   21,711
                                                                                                                     ----------
(Loss) before income taxes............                                                                               $  (23,225)
                                                                                                                     ==========

Identifiable assets...................     $  523,928   $   96,127   $       88   $67,892    $  37,252   $       -   $  725,287
                                           ==========   ==========   ==========   =======    =========   =========   ==========

<CAPTION>

                                               Gas
                                            Gathering                                                      Elim-
                                               and       Producing                 Trans-                 inating
                                           Processing   Properties   Marketing    mission    Corporate    Entries      Total
                                           ----------   ----------   ----------   -------    ---------   ---------   ----------
<S>                                        <C>          <C>          <C>          <C>        <C>         <C>         <C>
Nine months ended September 30, 1998
Revenues from unaffiliated
customers.............................     $   27,938   $    1,453   $1,545,803   $ 3,879    $     678   $     617   $1,580,368
Interest income.......................              1            -            -         -       26,551     (25,625)         927
Other, net............................         15,360          703          143       (16)           -           -       16,190
Intersegment sales....................        328,670       18,253       61,324     8,346            -    (416,593)           -
                                           ----------   ----------   ----------   -------    ---------   ---------   ----------
Total revenues........................        371,969       20,409    1,607,270    12,209       27,229    (441,601)   1,597,485
                                           ----------   ----------   ----------   -------    ---------   ---------   ----------
Product purchases.....................        257,428        1,021    1,584,718       126       (2,665)   (410,793)   1,429,835
Plant operating expense...............         51,624        1,653        4,651     7,533        2,564      (5,106)      62,919
Oil and gas exploration
and production expense................              -        4,877          125         -            2          41        5,045
                                           ----------   ----------   ----------   -------    ---------   ---------   ----------
Operating margin......................     $   62,917   $   12,858   $   17,776   $ 4,550    $  27,328   $ (25,743)  $   99,686
                                           ==========   ==========   ==========   =======    =========   =========   ==========

Depreciation, depletion and
amortization..........................         27,796        8,518        3,139       760        3,494        (102)      43,605
Interest expense......................                                                                                   25,265
Selling and administrative expense....                                                                                   21,824
                                                                                                                     ----------
Income before income taxes............                                                                               $    8,992
                                                                                                                     ==========

Identifiable assets...................     $  649,423   $  108,527   $  119,735   $56,215    $  32,793   $       -   $  966,693
                                           ==========   ==========   ==========   =======    =========   =========   ==========
</TABLE>

                                       10
<PAGE>

   DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES

In June 1998, the Financial Accounting Standards Board ("FASB") issued Statement
of Financial Accounting Standards No. 133, "Accounting for Derivative
Instruments and Hedging Activities," ("SFAS No. 133") with an effective date for
fiscal years beginning after June 15, 1999. In June 1999, FASB issued Statement
of Financial Accounting Standards No. 137, "Accounting for Derivative
Instruments and Hedging Activities-Deferral of the Effective Date of FASB
Statement No. 133" ("SFAS No. 137").  SFAS No. 137 amended the earlier statement
to defer the effective date one year.  The statement will now be effective for
all fiscal quarters of all fiscal years beginning after June 15, 2000.  We have
not yet completed our evaluation of the impact that SFAS No. 133 will have upon
our financial statements. When required, we will comply with the accounting and
reporting requirements of SFAS No. 133.

   LEGAL PROCEEDINGS

Reference is made to "Part II - Other Information - Item 1. Legal Proceedings,"
of this Form 10-Q.

                                       11
<PAGE>

ITEM 2.  MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
         -----------------------------------------------------------------------
         OF OPERATIONS
         -------------

The following discussion and analysis relates to factors, which have affected
our consolidated financial condition and our results of operations for the three
and nine month periods ended September 30, 1999 and 1998.  Certain prior year
amounts have been reclassified to conform to the presentation used in 1999.
Reference should also be made to our interim consolidated financial statements
and notes thereto included elsewhere in this document.  This section, as well as
other sections in this Form 10-Q, contain "forward-looking statements" within
the meaning of the Private Securities Litigation Reform Act of 1995, which can
be identified by the use of forward-looking terminology, such as "may,"
"intend," "will," "expect," "anticipate," "estimate," or "continue" or the
negative thereof or other variations thereon or comparable terminology.  In
addition to the important factors referred to herein, numerous factors affecting
the gas processing industry generally and in the specific markets for gas and
NGLs in which we operate, could cause actual results to differ materially from
those in such forward-looking statements.

Results of Operations

Three and nine months ended September 30, 1999 compared to the three and nine
months ended September 30, 1998
(Dollars in thousands, except per share amounts and operating data).

<TABLE>
<CAPTION>
                                                   Three Months Ended                   Nine Months Ended
                                                      September 30,                        September 30,
                                                  -------------------   Percent      -----------------------    Percent
                                                    1999       1998     Change          1999         1998       Change
                                                  --------   --------   -------      ----------   ----------    -------
<S>                                               <C>        <C>        <C>          <C>          <C>           <C>
Financial results:
Revenues...................................       $505,577   $516,259        (2)     $1,369,522   $1,597,485       (14)
Gross profit...............................         16,794      8,307       102          23,604       56,081       (58)
Net income (loss)..........................          1,058     (4,647)        -         (15,882)       5,893         -
Income (loss) per share of common stock....           (.05)      (.23)       78            (.74)        (.06)        -
Income (loss) per share of common stock -
     assuming dilution.....................           (.05)      (.23)       78            (.73)        (.06)        -
Net cash (used in) provided by
  operating activities.....................       $ 15,827   $(44,416)        -      $   59,575   $  (55,288)        -

Operating data:
Average gas sales (MMcf/D).................          1,775      2,295       (23)          1,960        2,200       (11)
Average NGL sales (MGal/D).................          2,815      4,345       (35)          2,875        4,540       (37)
Average gas prices ($/Mcf).................       $   2.41   $   1.90       (27)     $     2.07   $     2.01         3
Average NGL prices ($/Gal).................       $    .38   $    .25       (52)     $      .30   $      .27        11

</TABLE>

Net income increased $5.7 million and decreased $21.8 million for the three and
nine months ended September 30, 1999, respectively, compared to the same periods
in 1998.  The increase in net income for the third quarter was primarily due to
increased prices, as well as lower operating costs.  The decrease for the nine
month period was primarily due to losses of $14.2 million associated with the
sales of the Giddings gathering systems and the Katy facility, severance charges
associated with a corporate restructuring of $700,000 and an extraordinary loss
on the early extinguishment of debt of $1.1 million.  Also included in the 1998
results was the gain on the sale of the Perkins facility.

Revenues from the sale of residue gas decreased approximately $9.9 million to
$392.7 million for the quarter ended September 30, 1999 compared to the same
period in 1998, as average gas sales volumes decreased 520 MMcf per day to 1,775
MMcf per day and average gas prices increased $.51 per Mcf to $2.41 per Mcf.
The decrease in sales volumes was primarily related to the reduction in the sale
of residue gas purchased from third parties.  The reduction in third party sales
was prompted by a continuing reduction in margins obtained on the sale of third
party residue gas.

Revenues from the sale of residue gas decreased approximately $99.8 million to
$1,107.7 million for the nine months ended September 30, 1999 compared to the
same period in 1998, as average gas sales volumes decreased 240 MMcf per day to
1,960 MMcf per day and average gas prices increased $.06 per Mcf to $2.07 per
Mcf. The decrease in sales volumes was primarily

                                       12
<PAGE>

related to the reduction in the sale of residue gas purchased from third
parties. The reduction in third party sales was prompted by a continuing
reduction in margins obtained on the sale of third party residue gas.

Included in the average gas price was approximately $2.0 million and $2.3
million of loss recognized for the three and nine months ended September 30,
1999, respectively, related to futures positions on equity gas volumes.  We have
entered into futures positions for a portion of our equity gas for the remainder
of 1999 and in 2000.  See further discussion in "Liquidity and Capital Resources
- Risk Management Activities."

Revenues from the sale of NGLs decreased approximately $2.3 million to $97.7
million for the quarter ended September 30, 1999 compared to the same period in
1998 as average NGL sales volumes decreased 1,530 MGal per day to 2,815 MGal per
day although average NGL prices increased $.13 per gallon to $.38 per gallon.
The decreases in sales volumes were related to a decrease in sales of NGLs
purchased from third parties and a decrease in plant sales volumes.  Plant NGL
sales volumes were largely affected by increased volumes taken in kind and
curtailed drilling activity due to low oil prices by a producer behind Midkiff,
and the sale of the Edgewood and Giddings facilities.  Volumes taken in kind
affect sales volumes and revenues but do not materially affect income.

Revenues from the sale of NGLs decreased approximately $95.1 million to $237.5
million for the nine months ended September 30, 1999 compared to the same period
in 1998 as average NGL sales volumes decreased 1,665 MGal per day to 2,875 MGal
per day and average NGL prices increased $.03 per gallon to $.30 per gallon.
Plant sales volumes were largely affected by increased volumes taken in kind and
curtailed drilling activity due to low oil prices by a producer behind Midkiff,
and the sale of the Giddings and Edgewood facilities. Volumes taken in kind
affect sales volumes and revenues but do not materially affect income.

Included in the average NGL prices was approximately $2.4 million and $4.4
million of loss recognized for the three and nine months ended September 30,
1999, respectively, related to futures positions on equity volumes.  We have
entered into futures positions for a portion of our equity production for the
remainder of 1999 and in 2000.  See further discussion in "Liquidity and Capital
Resources - Risk Management Activities."

Overall, excluding the impact of the plants sold in 1998 and 1999, the
production of residue gas and NGLs at our facilities increased in both the three
and nine month periods ended September 30, 1999.

Other net revenue decreased $36.5 million for the nine months ended September
30, 1999 due to the net losses on the sales of the Katy, Giddings and MiVida
assets of $22.3 million in 1999 compared to a $14.9 million gain recognized on
the sale of the Perkins facility in March 1998.

Product purchases decreased $13.1 million and decreased $178.4 million for the
three and nine months ended September 30, 1999, respectively, compared to the
same periods in 1998.  The decrease in product purchases in both periods is
primarily due to a decrease in sales volumes of product purchased from third
parties. Overall product purchases as a percentage of residue gas and NGL sales
remained the same at 93% for the three and nine months ended September 30, 1999,
respectively, as compared to the same periods in 1998.

Plant operating expense decreased $5.2 million and $12.3 million, respectively,
for the three and nine months ended September 30, 1999 compared to the same
periods in 1998.  The decreases are primarily due to reductions in labor,
increased operational efficiencies and the asset sales.

Depreciation, depletion and amortization decreased $1.2 million and $5.8 million
for the three and nine month periods ended September 30, 1999, respectively,
compared to the same periods in 1998.  The decrease is primarily due to a
reduction in depreciation of the Bethel facility resulting from an impairment
charge recorded in the fourth quarter of 1998 and the sale of assets in 1998 and
1999.

Selling and administrative expense decreased $1.2 million for the three months
ended September 30, 1999.  The decrease was primarily related to reductions in
labor, resulting from the sale of assets and reductions in residue gas sales
volumes in 1998 and 1999.

                                       13
<PAGE>

Liquidity and Capital Resources

Our sources of liquidity and capital resources historically have been net cash
provided by operating activities, funds available under our financing facilities
and proceeds from offerings of debt and equity securities.  In the past, these
sources have been sufficient to meet our needs and finance the growth of our
business.  We can give no assurance that the historical sources of liquidity and
capital resources will be available for future development and acquisition
projects, and we may be required to seek alternative financing sources.  In
1998, sources of liquidity included the sales of the Perkins facility and the
Edgewood facility and related production.  In the second quarter of 1999, we
completed the sales of our Giddings, Katy and MiVida facilities.  In connection
with the sale of Katy, we sold gas held in storage at this facility.  The total
gross proceeds from these 1999 transactions was $160.0 million.  We used the
proceeds from these sales to reduce debt.  Product prices, sales of inventory,
the volumes of natural gas processed by our facilities, the margin on third-
party product purchased for resale, as well as the timely collection of our
receivables will affect all future net cash provided by operating activities.
Additionally, our future growth will be dependent upon obtaining additions to
dedicated plant reserves, acquisitions, new project development, marketing,
efficient operation of our facilities and our ability to obtain financing at
favorable terms.

We believe that the amounts available to be borrowed under the Revolving Credit
Facility, together with net cash provided by operating activities and the sale
of non-strategic assets, will provide us with sufficient funds to connect new
reserves, maintain our existing facilities and complete our current capital
expenditure program.  Depending on the timing and the amount of our future
projects, we may be required to seek additional sources of capital.  Our ability
to secure such capital is restricted by our financing facilities, although we
may request additional borrowing capacity from our lenders, seek waivers from
our lenders to permit us to borrow funds from third parties, seek replacement
financing facilities from other lenders, use stock as a currency for
acquisitions, sell existing assets or a combination of such alternatives.  While
we believe that we would be able to secure additional financing, if required, we
can provide no assurance that we will be able to do so or as to the terms of any
such financing.  We also believe that cash provided by operating activities and
amounts available under our Revolving Credit Facility will be sufficient to meet
our debt service and preferred stock dividend requirements for the remainder of
1999.

Historically, while certain individual plants have experienced declines in
dedicated reserves, we have been successful in connecting additional reserves to
more than offset the natural declines. There has been a reduction in drilling
activity, primarily in basins that produce oil and casinghead gas, from levels
that existed in prior years.  However, higher gas prices experienced over the
last several years, improved technology, e.g., 3-D seismic and horizontal
drilling, and increased pipeline capacity from the Rocky Mountain region have
stimulated drilling in the Powder River basin and Southwest Wyoming.  The
overall level of drilling will depend upon, among other factors, the prices for
gas and oil, the drilling budgets of third-party producers, the energy policy of
the federal government and the availability of foreign oil and gas, none of
which is within our control. We have increased our dedicated estimated plant
reserves from 2.2 Tcf at December 31, 1993 to 3.1 Tcf at December 31, 1998.   On
average, over this five year period, including the reserves associated with our
joint ventures and partnerships and excluding the facilities sold during this
period, we connected new reserves to our facilities to replace approximately
165% of throughput over this period.  There is no assurance that we will
continue to be successful in replacing the dedicated reserves processed at our
facilities.

In addition to the registration statement for the Exchange Offer discussed above
under "Sale of Senior Subordinated Debt," we have effective shelf registration
statements filed with the Commission for an aggregate of $200 million of debt
securities and preferred stock, along with the shares of common stock, if any,
into which such securities are convertible, and $62 million of debt securities,
preferred stock or common stock.

                                       14
<PAGE>

Our sources and uses of funds for the nine months ended September 30, 1999 are
summarized as follows (In thousands):

<TABLE>
<CAPTION>

Sources of funds:
<S>                                                              <C>
     Borrowings under revolving credit facility................  $1,815,500
     Proceeds from the dispositions of property and equipment..     148,100
     Proceeds from issuance of long-term debt..................     155,000
     Net cash provided by operating activities.................      59,575
     Proceeds from exercise of common stock options............          54
                                                                 ----------
       Total sources of funds..................................  $2,178,229
                                                                 ==========
Uses of funds:
     Payments related to long-term debt........................  $2,115,366
     Capital expenditures......................................      49,043
     Dividends paid............................................      12,648
                                                                 ----------
       Total uses of funds.....................................  $2,177,157
                                                                 ==========
</TABLE>

Additional sources of liquidity available to us are our inventories of gas and
NGLs in storage facilities.  We store gas and NGLs primarily to ensure an
adequate supply for long-term sales contracts and for resale during periods when
prices are favorable.  We held gas in storage and in imbalances of approximately
10.9 Bcf at an average cost of $2.18 per Mcf at September 30, 1999 compared to
21.3 Bcf at an average cost of $2.08 per Mcf at September 30, 1998 under storage
contracts at various third-party facilities.  At September 30, 1999, we had
hedging contracts in place for anticipated sales of approximately 10.8 Bcf of
stored gas at a weighted average price of $2.38 per Mcf for the stored
inventory.

We held NGLs in storage of 15,700 MGal, consisting primarily of propane and
normal butane, at an average cost of $.36 per gallon and 50,700 MGal at an
average cost of $.28 per gallon at September 30, 1999 and 1998, respectively, at
various third-party storage facilities.   At September 30, 1999, we had no
significant hedging contracts in place for anticipated sales of stored NGLs.

Capital Investment Program

Largely as a result of low commodity prices experienced in the first half of
1999, we have reduced our budget for capital expenditures in 1999 from the
levels expended in 1997 and 1998.  We expect capital expenditures related to
existing operations to be approximately $78.3 million during 1999, consisting of
the following: (i) approximately $41.4 million related to gathering, processing
and pipeline assets, of which $6.3 million is for maintaining existing
facilities; (ii) approximately $33.5 million on exploration and production
activities; and (iii) approximately $3.4 million for miscellaneous items.
Overall, capital expenditures in the Powder River basin coal bed methane
development and in Southwest Wyoming operations represent 57% and 20%,
respectively, of the total 1999 budget. As of September 30, 1999, we have
expended $49.1 million, consisting of the following: (i) $28.4 million for new
connects, system expansions and asset consolidations; (ii) $1.6 million for
maintaining existing facilities; (iii) $18.0 million for exploration and
production activities; and (iv) $1.1 million related to other miscellaneous
items.

Powder River Basin - We continue to develop our Powder River basin coal bed
methane natural gas gathering system and our coal seam gas reserves in Wyoming.
We have acquired drilling rights on 830,000 gross acres (or 425,000 net acres)
in the vicinity of known coal bed methane production. We and other operators in
the area have established production from wells drilled to depths of 400 to
1,200 feet.  Together with our partner, we expect to drill approximately 580
wells in 1999, of which approximately 484 have been drilled through September
30, 1999, all of which are on locations with proven, undeveloped reserves.  The
average drilling, completion and gathering cost for our coal bed methane wells
is approximately $65,000 with proven reserves per well of approximately 320
MMcf. As deeper wells are drilled, the average cost per well is expected to
increase.  Production of coal bed methane from the Powder River basin has been
expanding, and approximately 139 MMcf/D of gas volumes in the third quarter of
1999 were being produced by several operators in the area as compared to 61
MMcf/D in January 1998.   Approximately 63% of this production is from acreage
equally owned by our partner, Barrett Resources Corporation, and us.  We
transport most of the coal bed methane gas through our MIGC interstate pipeline
located in Wyoming, for redelivery to gas markets in the Rocky Mountain and
Midwest regions of the United States.

                                       15
<PAGE>

Current drilling schedules on federal acreage are being delayed subject to
approval of the Wyodak Environmental Impact Statement.  The record decision for
this environmental impact statement is expected to be issued in November 1999.
The wells expected to be allowed by this environmental impact statement have
been permitted.  Further drilling permits will require additional environmental
studies.  However, we can make no assurance as to the timing or conditions of
any future studies. Our drilling plans for the years 2000 and 2001 are primarily
scheduled on fee and state lands which will not require federal permits.

In addition, the Wyoming Department of Environmental Quality is reviewing the
water discharge and quality standards in the Powder River basin, and this review
is causing a delay in the issuance of water disposal permits. Currently
individual well permits are being issued in certain areas. We believe that the
conditions under which water disposal permits will be issued will be clarified
within the second quarter of 2000. However, we can make no assurance that the
conditions under which permits are granted will not impact the level of drilling
or the timing of production.

In December 1998, we joined with other industry partners to form Fort Union Gas
Gathering, L.L.C., which has substantially completed the 106-mile long, 24-inch
gathering pipeline and treater to gather and treat natural gas produced in the
Powder River basin.  We own a 13% equity interest in Fort Union and are the
construction manager and field operator.  We expect this new gathering pipeline
to have an initial capacity of approximately 450 MMcf/D of natural gas with
expansion capability.  The pipeline became operational in September 1999.

Southwest Wyoming - The United States Geologic Survey estimates that the Greater
Green River basin contains over 120 Tcf of unrecovered natural gas reserves.
Our facilities are located in the Southwest Wyoming portion of this basin.  They
include the Granger gathering and processing facility and our 72% ownership
interest in the Lincoln Road gathering and processing facility.  These
facilities have a combined operational capacity of 225 MMcf/D and processed an
average of 180 MMcf/D in the third quarter of 1999.  We believe that as
governmental drilling restrictions affecting a portion of our service area in
this basin are removed in the first half of 2000, we may have the opportunity to
expand these facilities in future years.

                                       16
<PAGE>

Financing Facilities

Revolving Credit Facility.   The Revolving Credit Facility is with a syndicate
of banks and provides for a maximum borrowing commitment of $250 million
consisting of an $83 million 364-day Revolving Credit Facility, or Tranche A,
and a five-year $167 million Revolving Credit Facility, or Tranche B.   At
September 30, 1999, $29.0 million was outstanding on this facility.  The
Revolving Credit Facility bears interest at certain spreads over the Eurodollar
rate, or the greater of the Federal Funds rate or the agent bank's prime rate.
We have the option to determine which rate will be used. We also pay a facility
fee on the commitment. The interest rate spreads and facility fee are adjusted
based on our debt to capitalization ratio and range from .75% to 2.00%. At
September 30, 1999, the interest rate payable on the facility was 6.88%.  We are
required to maintain a total debt to capitalization ratio of not more than 60%
through December 31, 2000 and of not more than 55% thereafter, and a senior debt
to capitalization ratio of not more than 40% beginning September 30, 1999
through December 31, 2001 and of not more than 35% thereafter. The agreement
also requires a ratio of EBITDA, excluding certain non-recurring items, to
interest and dividends on preferred stock as of the end of any fiscal quarter,
for the four preceding fiscal quarters, of not less than 1.35 to 1.0 beginning
June 30, 1999 and increasing to 3.25 to 1.0 by December 31, 2002. This facility
is guaranteed and secured via a pledge of the stock of certain of our
subsidiaries. We generally utilize excess daily funds to reduce any outstanding
balances on the Revolving Credit Facility and associated interest expense, and
we intend to continue such practice.

Master Shelf Agreement.   In December 1991, we entered into a Master Shelf
Agreement with The Prudential Insurance Company of America. Amounts outstanding
under the Master Shelf Agreement at September 30, 1999 are as indicated in the
following table (dollars in thousands):


<TABLE>
<CAPTION>
                                      Interest         Final
      Issue Date           Amount       Rate         Maturity                      Principal Payments Due
-----------------------  ----------  ----------  -----------------   ------------------------------------------------------
<S>                      <C>         <C>         <C>                 <C>
October 27, 1992           $  8,334       7.51%  October 27, 1999    single payment was made at maturity
October 27, 1992             25,000       7.99%  October 27, 2003    $8,333 on each of October 27, 2001 through 2003
December 27, 1993            25,000       7.23%  December 27, 2003   single payment at maturity
October 27, 1994             25,000       9.05%  October 27, 2001    single payment at maturity
October 27, 1994             25,000       9.24%  October 27, 2004    single payment at maturity
July 28, 1995                50,000       7.61%  July 28, 2007       $10,000 on each of July 28, 2003 through 2007
                           --------
                           $158,334
                           ========
</TABLE>


In April 1999, effective January 1999, we amended our agreement with Prudential
to reflect the following provisions. We are required to maintain a current
ratio, as defined therein, of at least .9 to 1.0, a minimum tangible net worth
equal to the sum of $300 million plus 50% of consolidated net earnings earned
from January 1, 1999 plus 75% of the net proceeds of any equity offerings after
January 1, 1999, a total debt to capitalization ratio of not more than 60%
through December 31, 2001 and of not more than 55% thereafter and a senior debt
to capitalization ratio of 40% through March 2002 and 35% thereafter. This
amendment also requires an EBITDA to interest ratio of not less than 1.75 to 1.0
increasing to a ratio of not less than 3.75 to 1.0 by March 31, 2002 and an
EBITDA to interest on senior debt ratio of not less than 1.75 to 1.0 increasing
to a ratio of not less than 5.50 to 1.0 by March 31, 2002.  EBITDA in these
calculations excludes certain non-recurring items.  In addition, we are
prohibited from declaring or paying dividends that in the aggregate exceed the
sum of $50 million plus 50% of consolidated net income earned after June 30,
1995, or minus 100% of a net loss, plus the aggregate net cash proceeds received
after June 30, 1995 from the sale of any stock. At September 30, 1999,
approximately $25.7 million was available under this limitation. We financed the
$8.3 million payment due in October 1999 with amounts available under the
Revolving Credit Facility. Borrowings under the Master Shelf Agreement are
guaranteed and secured via a pledge of the stock of certain of our subsidiaries.

In June 1999, we prepaid approximately $33.3 million of notes outstanding under
the Master Shelf Agreement with proceeds from the offering of the Subordinated
Notes.

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<PAGE>

1995 Senior Notes.   In 1995, we sold $42 million of Senior Notes, the 1995
Senior Notes, to a group of insurance companies with an interest rate of 8.16%
per annum. In March 1999, we prepaid $15 million of the principal amount
outstanding on the 1995 Senior Notes at par. These payments were financed by a
portion of the $37 million Bridge Loan described below and by amounts available
under the Revolving Credit Facility. The remaining principal amount outstanding
of $27 million is due in a single payment in December 2005. The 1995 Senior
Notes are guaranteed and secured via a pledge of the stock of certain of our
subsidiaries. This facility contains covenants similar to the Master Shelf
Agreement. In the second quarter of 1999, we posted letters of credit for a
total of approximately $10.8 million for the benefit of the holders of the 1995
Senior Notes.

We are currently paying an annual fee of not more than .65% on the amounts
outstanding on the Master Shelf Agreement and the 1995 Senior Notes. This fee
will continue until we have received an implied investment grade rating on our
senior secured debt. This fee is not assessed on the portion of the 1995 Senior
Notes for which letters of credit are posted.

1993 Senior Notes.   In 1993, we sold $50 million of 7.65% Senior Notes, the
1993 Senior Notes, to a group of insurance companies. Scheduled annual principal
payments of $7.1 million on the 1993 Senior Notes were made on April 30 of 1997
and 1998. In February 1999, we prepaid $33.5 million of the total principal
amounts outstanding of $35.6 million at par. These payments were financed by a
portion of the $37 million Bridge Loan. We prepaid the remaining outstanding
principal of $2.1 million in April 1999 with amounts available under the
Revolving Credit Facility.

In connection with the repayments on the Master Shelf Agreement, the 1995 Senior
Notes and the 1993 Senior Notes, we incurred approximately $1.8 million of pre-
tax yield maintenance and other charges.  These charges are reflected as an
extraordinary loss from early extinguishment of long-term debt in the second
quarter of 1999.

Bridge Loan.   In February 1999, in order to finance prepayments of amounts
outstanding on the 1993 and 1995 Senior Notes, we entered into a Bridge Loan
agreement in the amount of $37 million with our agent bank. This facility was
paid in full in April 1999 with proceeds from the sale of the Katy facility.

Senior Subordinated Notes.  In June 1999, we sold $155.0 million of Senior
Subordinated Notes in a private placement.  The Subordinated Notes bear interest
at 10% and were priced at 99.225% to yield 10.125%.   These notes contain
maintenance covenants which include limitations on debt incurrence, restricted
payments, liens and sales of assets. The Subordinated Notes are unsecured and
are guaranteed on a subordinated basis by certain of our subsidiaries. We are in
the process of making a registered Exchange Offer to the private noteholders to
exchange these privately placed notes for registered publicly tradable notes
under the same terms and conditions.


Covenant Compliance.   Taking into account all the covenants contained in these
agreements, we had approximately $124.0 million of available borrowing capacity
at September 30, 1999. In the second quarter of 1999, we amended our various
financing facilities providing for financial flexibility and covenant
modifications and issued the Subordinated Notes.   These amendments were needed
given the depressed commodity pricing experienced in the industry in general at
that time and the disappointing results at our Bethel Treating facility. We can
provide no assurance that further amendments or waivers can be obtained in the
future, if necessary, or that the terms would be favorable to us. To strengthen
our credit ratings and to reduce our overall debt outstanding, we will continue
to dispose of non-strategic assets and investigate alternative financing sources
including the issuance of public debt, project-financing, joint ventures and
operating leases.

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<PAGE>

                                  SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this amended report to be signed on its behalf by the
undersigned, thereunto duly authorized.

                                      WESTERN GAS RESOURCES, INC.
                                      ---------------------------
                                      (Registrant)


Date: November 24, 1999               By: /s/ LANNY F. OUTLAW
                                          -------------------------------------
                                          Lanny F. Outlaw
                                          Chief Executive Officer and President


Date: November 24, 1999               By: /s/ WILLIAM J. KRYSIAK
                                          --------------------------------------
                                          William J. Krysiak
                                          Vice President - Finance
                                          (Principal Financial and Accounting
                                          Officer)

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