<PAGE>
 
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   FORM 10-Q/A
                                 AMENDMENT NO. 1


               QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF
                      THE SECURITIES EXCHANGE ACT OF 1934

 For the Quarter Ended June 30, 1997        Commission File Number 0-18858

                              KAISER VENTURES INC.
                              --------------------
             (Exact name of registrant as specified in its charter)

            DELAWARE                                          94-0594733
  -------------------------------                         -------------------
  (State or other jurisdiction of                         (I.R.S. Employer
  incorporation or organization)                          Identification No.)

                    3633 East Inland Empire Blvd., Suite 850
                            Ontario, California 91764
              -----------------------------------------------------
              (Address of principal executive offices and zip code)

Registrant's telephone number, including area code: (909) 483-8500

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
                                       ---                             

Indicate by check mark whether registrant has filed all documents and reports
required to be filed by Sections l2, 13 or l5(d) of the Securities Exchange Act
of 1934 subsequent to the distribution of securities under a plan confirmed by a
court.

                                    Yes X  No
                                       ---

On August 6, 1997, the Company had 10,521,975 shares of Common Stock, $.03 par
value, outstanding (including 136,919 shares deemed outstanding and held in
reserve by the Company for issuance to the former general unsecured creditors of
Kaiser Steel Corporation pursuant to its Plan of Reorganization).
<PAGE>
 
1. Amendment to Consolidated Balance Sheet - Part I, Item 2.

         As filed with the Securities and Exchange Commission via EDGAR, the
numbers for "Investment in common stock of Penske Motorsports, Inc." were
transposed as set forth on the Assets page of the Consolidated Balance Sheet.
Accordingly, the Assets page of the Consolidated Balance Sheet is hereby amended
to read as follows:

                           CONSOLIDATED BALANCE SHEETS

                                      AS OF
<TABLE>
<CAPTION>
                                                          JUNE 30,       DECEMBER 31,
                                                            1997           1996
                                                            ----           ----
                                                          (Unaudited)
<S>                                                     <C>            <C>         
ASSETS
Current Assets
   Cash and cash equivalents........................... $  4,734,000   $  8,482,000
   Accounts receivable and other, net of allowance for
    doubtful accounts of $1,387,000 and $1,034,000,
    respectively.......................................    5,957,000      3,217,000
    Insurance settlement receivable....................      119,000        119,000
                                                        ------------   ------------

                                                          10,810,000     11,818,000
                                                        ------------   ------------

Investment in common stock of Penske Motorsports, Inc.
 (Fair market value of 1,627,923 shares equal to
 $53,005,000 as of June 30, 1997)......................   39,978,000     38,863,000
                                                        ------------   ------------

Investment in Fontana Union Water Company..............   16,108,000     16,108,000
                                                        ------------   ------------

Investment in West Valley MRF..........................    2,326,000      1,024,000
                                                        ------------   ------------
Real Estate
   Land and improvements...............................   52,980,000     52,274,000
   Real estate under development.......................    4,412,000      6,393,000
                                                        ------------   ------------

                                                          57,392,000     58,667,000
                                                        ------------   ------------

Other Assets
   Landfill permitting and development.................    8,287,000      5,645,000
   Buildings and equipment (net).......................    2,668,000      2,210,000
                                                        ------------   ------------

                                                          10,955,000      7,855,000
                                                        ------------   ------------

Total Assets........................................... $137,569,000   $134,335,000
                                                        ============   ============
</TABLE>



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

                                        1
<PAGE>
 
                                   SIGNATURES

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

                                                     KAISER VENTURES INC.


Dated: September 2, 1997                             /s/ James F. Verhey
                                                     -------------------------
                                                     James F. Verhey
                                                     Principal Financial Officer



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