<PAGE>
 
               UNITED STATES SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C.  20549
    
                                   FORM 10-Q/A     



COMMISSION FILE NO. 1-2714

(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, 1997
                                              ------------------

                                or


( ) Transition Report Pursuant to Section 13 or 15(d) of the Securities
    Exchange Act of 1934
             For the transition period from ________________________
                                        to  ________________________



                               ATLAS CORPORATION
                         -----------------------------
                     (Exact name of registrant as specified
                                in its charter)



                 DELAWARE                                   13-5503312
      -------------------------------                    ----------------
      (State or other jurisdiction of                   (I. R. S. Employer
      incorporation or organization)                    Identification No.)



             370 Seventeenth Street, Suite 3050, Denver, CO  80202
             -----------------------------------------------------
                    (Address of principal executive offices)
                                   (Zip Code)



                                 303-629-2440
                        -------------------------------
                        (Registrant's telephone number,
                              including area code)

    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  
                                    -----    -----      

As of November 10, 1997, 27,206,858 shares of Common Stock, par value $1 per
share, were issued and outstanding.

<PAGE>
 
                        PART I.  FINANCIAL INFORMATION



ITEM 1.  FINANCIAL STATEMENTS.
         -------------------- 

                               ATLAS CORPORATION
                          CONSOLIDATED BALANCE SHEETS
                                 (in Thousands)


<TABLE>    
<CAPTION>
                                                                             
                                                        September 30,       December 31,
                                                            1997                1996
-------------------------------------------------------------------------------------------
                                                         (Unaudited)
<S>                                                      <C>                 <C> 
ASSETS
Current Assets:
 Cash and cash equivalents                                $   240                $ 1,099
 Accounts receivable - trade                                  622                    270
 Accounts receivable - other                                  613                    469
 Inventories                                                1,029                    848
 Prepaid expenses and other current assets                     96                    195
                                                          --------             ---------
  Total current assets                                      2,600                  2,881
                                                          --------             ---------

Property, plant and equipment                              65,990                 64,166
Less, accumulated depreciation, depletion,
 amortization and impairment                              (45,475)               (44,779)
                                                          --------             ---------
                                                           20,515                 19,387
Investment in Vista Gold Corp. (Notes 5 and 9)                 --                 11,542
Restricted cash and securities                              6,220                  6,266
Other assets                                                  563                  1,605
                                                          --------             ---------
                                                          $29,898                $41,681
                                                          ========             =========

LIABILITIES
Current liabilities:
 Trade accounts payable                                   $ 2,142                $ 1,544
 Accrued liabilities                                        2,299                  2,136
 Short-term debt (Note 7)                                   6,135                  2,129
 Deferred gain on joint venture agreement (Note 8)            750                     --
                                                          --------             ---------
  Total current liabilities                                11,326                  5,809

Long-term debt (Notes 6 and 9)                              2,300                 13,310
Other liabilities, long-term                                9,088                  9,505
Deferred gain on joint venture agreement (Note 8)             500                     --

Minority Interest                                             593                    685

Commitments and contingencies (Notes 4,12,13,14 and 15)

STOCKHOLDERS' EQUITY
Common stock (Notes 8 and 9)                               27,207                 24,180
Capital in excess of par value                             66,774                 68,514
Deficit                                                   (87,890)               (77,867)
Currency translation adjustment                                --                   (133)
Unrealized loss on investments in equity securities            --                 (2,322)
                                                          --------             ---------
  Total stockholders' equity                                6,091                 12,372
                                                          --------             ---------
                                                          $29,898                $41,681
                                                          ========             =========
</TABLE>      
See notes to consolidated financial statements.

                                                                    Page 2 of 16
<PAGE>
 
                               ATLAS CORPORATION

                     CONSOLIDATED STATEMENTS OF OPERATIONS
                (In Thousands, Except Per Share Data, Unaudited)


<TABLE>    
<CAPTION>
                                                Three Months Ended               Nine Months Ended
                                                   September 30,                   September 30,
                                          -----------------------------    ------------------------------
                                               1997             1996           1997            1996
---------------------------------------------------------------------------------------------------------
<S>                                         <C>               <C>             <C>             <C> 
Mining revenue                                $  1,140       $    --           $  2,789        $   --
Costs and expenses:
 Production costs                                1,098            --              2,490            --
 Depreciation, depletion and amortization          211            --                647            --
 Impairment of mineral property  (Note 11)          31            --              1,256            --
 Shutdown and standby costs                         96           268                328           829
 General and administrative expenses               551           746              1,809         3,592
 Exploration and prospecting costs                  69           968                708         1,136
                                            -----------      -------           --------      --------
  Gross Operating Loss                            (916)       (1,982)            (4,449)       (5,557)

Other (income) and expense:
 Interest expense                                  183           317                790           954
 Interest income                                  (103)         (113)              (299)         (442)
 Equity in loss of unconsolidated
  subsidiary (Note 5)                               --           770                 --         2,492
 Gain on sale of marketable securities              --            --                 --        (1,333)
 Gain from joint venture agreement (Note 8)       (187)           --               (250)           --
 Loss on repurchase of Debentures (Note 9)           8            --              5,419            --
 Other                                              47           (50)                 6           (37)
                                            -----------      -------           --------      --------
  Loss from continuing operations before
  taxes and minority interest                     (864)       (2,906)           (10,115)       (7,191)

Provision for income taxes                          --            --                 --            --
                                            -----------      -------           --------      --------
 Loss before minority interest                    (864)       (2,906)           (10,115)       (7,191)

Minority interest in net loss of subsidiary         19            72                 92           256
                                            -----------      -------           --------      --------
 Net loss                                      $  (845)      $(2,834)          $(10,023)     $ (6,935)
                                            ===========      =======           =========     ========
Per share of common stock:
 Loss from continuing operations               $ (0.03)      $ (0.14)           $ (0.40)     $  (0.35)
 Loss from discontinued operations                  --            --                 --            --
                                            -----------      -------           --------      --------
 Net loss                                      $ (0.03)      $ (0.14)           $ (0.40)     $  (0.35)
                                            ===========      =======           ========      ========
Average number of common
 shares outstanding                             27,161        20,115             25,323        20,086
                                            ===========      =======           ========      ========
</TABLE>      
See notes to consolidated financial statements.

                                                                    Page 3 of 16

<PAGE>
 
                               ATLAS CORPORATION
                     CONSOLIDATED STATEMENTS OF CASH FLOWS
                           (In Thousands, Unaudited)

<TABLE>    
<CAPTION>
 
                                                                       Nine Months Ended
                                                                          September 30,
                                                             ----------------------------------
                                                                  1997                 1996
-----------------------------------------------------------------------------------------------
<S>                                                          <C>                 <C> 
Operating activities:
 Net loss                                                     $(10,023)             $  (6,935)
Add (deduct) non-cash items:
 Depreciation, depletion, amortization                             774                     38
 Impairment of mineral property                                  1,256                     --
 Equity in loss of unconsolidated subsidiary                        --                  2,492
 Deferred gain on join venture agreement                          (250)                    --
 Gain on sale of marketable securities                              --                 (1,333)
 Loss on repurchase of Debentures                                5,419                     --
 Other                                                             (35)                  (241)
Net change in non-cash items
 Related to operations (Note 3)                                    546                 (2,797)
                                                      -------------------       --------------
  Cash used in continuing operations                            (2,313)                (8,294)
                                                      -------------------       --------------
From discontinued operations:
 Change in estimated uranium reclamation costs                    (192)                (1,051)
                                                      -------------------       --------------
  Cash provided by (used in) discontinued operations              (192)                (1,051)
                                                      -------------------       --------------
  Cash used in operating activities                             (2,505)                (9,345)
                                                      -------------------       --------------
Investing activities:
 Additions to property, plant and equipment                     (3,119)                (2,653)
 Proceeds from joint venture agreement                           1,500                     --
 Proceeds from issuance of debt released from escrow                --                 10,000
 Proceeds from sale of marketable securities                        76                  4,520
                                                      -------------------       --------------
  Cash provided by (used in) investing activities               (1,543)                11,867
                                                      -------------------       --------------
Financing activities:
 Repayment of short-term debt                                       --                 (2,000)
 Borrowings on short-term debt                                     506                     --
 Proceeds from issuance of stock                                   500                     --                               
 Proceeds from issuance of long-term debt                        2,300                     --
 Costs of repurchasing of Debentures                              (117)                    --
                                                      -------------------       --------------
  Cash used in financing activities                              3,189                 (2,000)
                                                      -------------------       --------------
Increase (decrease) in cash and cash equivalents                  (859)                   522

Cash and cash equivalents:
 Beginning of period                                             1,099                  1,607
                                                      -------------------       --------------
 End of period                                                $    240              $   2,129
                                                      ===================       ==============
</TABLE>     


See notes to consolidated financial statements.

                                                                    Page 4 of 16

<PAGE>
 
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
                                        

1. The accompanying consolidated financial statements have been prepared in
   accordance with generally accepted accounting principles for interim
   financial information and with the instructions to Form 10-Q and Article 10
   of Regulation S-X.  Accordingly, they do not include all of the information
   and footnotes required by generally accepted accounting principles for
   complete financial statements.  There has not been any change in the
   significant accounting policies of Atlas Corporation (the "Company") for the
   periods presented.

   In the opinion of Management, all adjustments (consisting of normal recurring
   accruals) considered necessary for a fair presentation have been included.
   The results for these interim periods are not necessarily indicative of
   results for the entire year. These statements should be read in conjunction
   with the consolidated financial statements and notes thereto included in the
   Company's Annual Report of Form 10-K for the fiscal year ended December 31,
   1996.

   Certain of the comparative figures have been reclassified to conform with the
   current year's presentation.

2. In February 1997, the Financial Accounting Standards Board issued Statement
   No. 128, Earnings per Share, which is required to be adopted on December 31,
   1997.  At that time, the Company will be required to change the method
   currently used to compute earnings per share and to restate all prior
   periods.  Under the new requirements for calculating primary earnings per
   share, the dilutive effect of stock options will be excluded.  The impact of
   Statement 128 on the calculation of primary and fully diluted earnings per
   share for the periods ended September 30, 1997 and September 30, 1996 is not
   expected to be material.

   There has been no dilution of earnings per share as a result of the exercise
   of Option Warrants to Purchase Common Stock or stock options during the
   periods presented.


3. The components of the net change in items other than cash related to
   operating activities as reflected in the Consolidated Statements of Cash
   Flows are as follows:


<TABLE>    
<CAPTION>
 
                                                                   Nine Months Ended
                                                                     September 30,
                                                          ---------------------------------------
                                                                 1997                 1996
                                                          ------------------    -----------------
<S>                                                         <C>                   <C> 
Add (deduct) items other than cash:            
 Accounts receivable                                            $ (496)             $   251
 Inventories                                                      (181)                  --
 Prepaid expenses and other current assets                          99                  (89)
 Other assets                                                      189               (2,406)
 Trade accounts payable                                            457                 (733)
 Accrued liabilities                                               618                  127
 Other liabilities, long-term                                     (140)                  53
                                                          ------------------    -----------------
                                                                $  546              $(2,797)
                                                          ==================    =================
</TABLE>     

                                                                    Page 5 of 16

<PAGE>
 
  Gold Properties


  On March 21, 1997, the Company closed on the sale of its Musgrove Creek
  property to Meridian Gold Company ("Meridian") for a total sales price of
  $125,000, including $25,000 received in 1996.  In addition, Meridian assumed a
  reclamation obligation of $55,000, and conveyed to Atlas a 1% net smelter
  return royalty on claims previously owned by Atlas.  In the event Meridian
  places minerals at Musgrove Creek into production, Atlas will receive an
  additional $100,000.

  Exploration and development expenditures on the Gold Bar claim block will be
  funded by Barrick as described above.  With completion of the Gold Bar
  agreement (Note 8), and with other cost cutting measures recently implemented,
  the Company's holding costs on the property will decrease significantly in
  1997 to an estimated $350,000.  These costs will be funded from cash flow from
  operations, debt and equity financing and the Gold Bar sales proceeds.

  Carrying costs of Grassy Mountain and Doby George will be funded by the
  respective purchasers until a purchase decision is made.  While the Company
  has made expansion of the Bolivian operations its immediate focus, its long
  term strategy is both to grow its Bolivian operations, and to develop and
  expand the Company's interests in gold properties when market conditions
  improve.


  Reclamation Activities

  Final reclamation of the uranium mill site near Moab, Utah will commence
  following the issuance of a final Environmental Impact Statement on Atlas'
  reclamation plan. See below, "Results of Operations - Reclamation Activities".
  The total estimated cost of Atlas' proposed reclamation plan is $12-$17
  million.  As the Department of Energy will reimburse 56% of all reclamation
  costs under Title X, Atlas will be reimbursed for approximately $6.7-$9.5
  million in reclamation costs, leaving Atlas to fund $5.3-$7.5 million.  The
  Company has filed claims of $6.8 million for reimbursement of Title X
  reclamation costs incurred through March 1997 and has received payments of
  $4.3 million, leaving $2.5 million in Title X reimbursements due Atlas.  Atlas
  also has $4.2 million in restricted cash securing a Nuclear Regulatory
  Commission ("NRC") reclamation performance bond.  Based upon the amounts due
  the Company under Title X, and the restricted cash supporting the performance
  bond, the Company is confident that it will be able to fund and/or finance the
  anticipated costs for reclamation of its uranium mill and tailings site.

LIQUIDITY

  From the suspension of milling operations at the Gold Bar property in
  September 1994 until the acquisition of Arisur in October of 1996, the Company
  had no mining revenue and has funded its operating losses, capital and working
  capital requirements through a combination of the issuance of debt and equity
  instruments and the sale of assets.
    
  As of September 30, 1997, the working capital deficit was $8,726,000, compared
  to a deficit of $2,928,000 as of September 30, 1996.  The Company's current
  ratio at September 30, 1997 was .23 to 1, compared to .50 to 1 at September
  30, 1996.  The decrease during the year is a result of the Company's cash
  investment in Arisur of $3,600,000, development and construction costs of     

                                                                   Page 10 of 16

<PAGE>
     
  $3,273,000 at the Tucker Hill perlite property in Lakeview, Oregon,
  reclassification of the Company's $3,500,000 convertible debenture due in
  September 1998 to a current liability, ongoing general and administrative
  expenses of $2,900,000 and other operating and capital expenditures of
  $2,400,000.  These amounts have been offset by receipts from the sale of Vista
  shares of $5,603,000, the proceeds from the CAF loan of $2,300,000 and the
  Barrick purchase transaction of $2,000,000.     

  In order to fund near term capital requirements, the Company expects to
  utilize current cash available, cash flow from operations, the proceeds from
  the CAF loan, Title X receipts and proceeds from the sale of assets.  Longer
  term capital requirements will be satisfied from future operating cash flows,
  project financing and placement of additional debt or equity.

RESULTS OF OPERATIONS
    
  During the three and nine month periods ended September 30, 1997, the Company
  had mining revenue of $1,140,000 and $2,789,000 compared to no mining revenue
  in the same periods of 1996.  This is a result of the acquisition of Arisur in
  October 1996, which has operating lead, zinc and silver mines in Bolivia,
  South America.  Mining revenue was less than expected during the nine months
  ended September 30, 1997 due to flooding which cut off access to Don Francisco
  and Koyamayu and reduced production from Andacaba during the first quarter.
  This level of flooding is uncharacteristic and production from all mines has
  resumed.     

  Cash production costs were $1,098,000 and $2,490,000 during the three and nine
  month period ended September 30, 1997 compared to no costs during the similar
  periods of 1996, for the same reasons as noted above.  Production costs were
  also adversely impacted by the flooding noted above resulting in lower than
  expected operating cash flow of $509,000 for the nine months ended September
  30, 1997.

  Shutdown and standby costs at Gold Bar of $96,000 and $328,000 were incurred
  in the three and nine month periods ended September 30, 1997 compared to
  $268,000 and $829,000 for the comparable periods in 1996.  The decrease is a
  result of cost cutting measures implemented by the Company and the assumption
  by Barrick of certain property carrying costs at Gold Bar.

  Exploration costs for the three and nine month periods ending September 30,
  1997 were $69,000 and $708,000 compared to $968,000 and $1,136,000 for the
  comparable periods in 1996.  The 1997 amount includes a $450,000 charge
  pursuant to the Company's joint venture termination agreement with Vista Gold
  Corp., whereas the 1996 figures include a charge of $922,000 for exploration
  costs on the Commonwealth property pursuant to the Company's decision not to
  exercise its purchase option on the property.

  General and administrative expenses decreased during the three month period
  ended September 30, 1997 to $551,000 from $746,000 for the comparable period
  in 1996.  The $195,000 decrease during the period is due primarily to an
  overall cost reduction program undertaken in late 1996.  The largest reduction
  relates to salaries and benefits. General and administrative expenses during
  the nine month period ended September 30, 1997 were $1,809,000 compared to
  $3,592,000 for the comparable period in 1996.  The 1996 amount is a result of
  severance costs incurred in 1996 of $530,000 associated with resignation of
  David J. Birkenshaw as Chairman and CEO of the Company and also $300,000
  related to costs associated with the failed merger discussions with MSV
  Resources Inc., Company bonuses paid during the first 

                                                                   Page 11 of 16