1 EXHIBIT 5.1 [MAYER, BROWN & PLATT LETTERHEAD] August 10, 1999 Metal Management, Inc. 500 North Dearborn Street, Suite 405 Chicago, Illinois 60610 Ladies and Gentlemen: We have acted as your counsel in connection with the registration of certain 12 3/4% Senior Secured Notes due 2004 (the "Notes") of Metal Management, Inc., a Delaware corporation (the "Company"), and the guarantees thereof (the "Guarantees") by certain subsidiaries of the Company listed on Annex A hereto (the "Guarantors"), pursuant to a registration statement on Form S-4, registration no. 333-83547 (the "Registration Statement"). In rendering the opinions expressed herein, we have examined and relied upon such documents, corporate records, certificates of public officials and certificates as to factual matters executed by officers of the Company and the Guarantors as we have deemed necessary or appropriate. We have assumed the authenticity, accuracy and completeness of all documents, records and certificates submitted to us as originals, the conformity to the originals of all documents, records and certificates submitted to us as copies and the authenticity, accuracy and completeness of the originals of all documents, records and certificates submitted to us as copies. We have also assumed the legal capacity and genuineness of the signatures of persons signing all documents in connection with which the opinions expressed herein are rendered. Based upon the foregoing, we are of the opinion that: (i) the Notes have been duly authorized for issuance by the Company and, when the Notes are duly executed, authenticated, issued and delivered in accordance with the indenture governing the Notes, the Notes will be legally issued and will constitute a valid and legally binding obligations of the Company, except as may be limited by bankruptcy, insolvency, reorganization, moratorium or similar laws affecting creditors' rights generally or by the effect of general principles of equity, including, without limitation, concepts of materiality, reasonableness, good faith and fair dealing (regardless of whether considered in a proceeding at law or equity); and (ii) the Guarantees have been duly authorized for issuance by the Guarantors and, when the Guarantees are duly executed, authenticated, issued and delivered in accordance with 2 Metal Management, Inc. August 10, 1999 Page 2 the indenture governing the Notes, the Guarantees will be legally issued and will constitute valid and legally binding obligations of the Guarantors, except as may be limited by bankruptcy, insolvency, reorganization, moratorium or similar laws affecting creditors' rights generally or by the effect of general principles of equity, including, without limitation, concepts of materiality, reasonableness, good faith and fair dealing (regardless of whether considered in a proceeding at law or equity). We are admitted to practice law in the States of Illinois and New York and we express no opinions as to matters under or involving any laws other than the laws of the States of Illinois and New York, the federal laws of the United States of America and the corporate laws of the State of Delaware. We hereby consent to the filing of this opinion letter as an exhibit to the Registration Statement and to the reference to this firm under the caption "Legal Matters." Very truly yours, MAYER, BROWN & PLATT By /s/ Paul W. Theiss ----------------------------------------- Paul W. Theiss, a Partner of the Firm 3 ANNEX A Aerospace Metals, Inc., a Delaware corporation American Scrap Processing, Inc., an Illinois corporation California Metals Recycling, Inc., a California corporation CIM Trucking, Inc., an Illinois corporation Cometco Corp., an Illinois corporation Cozzi Building Corporation, an Illinois corporation Cozzi Iron & Metal, Inc., an Illinois corporation C Shredding Corp., an Illinois corporation EMCO Trading, Inc., an Arizona corporation Ferrex Trading Corporation, a Delaware corporation Firma, Inc., a California corporation Firma Plastic Co., Inc., a California corporation FPX, Inc., a Tennessee corporation Houston Compressed Steel Corp., a Texas corporation HouTex Metals Company, Inc., a Texas corporation The Isaac Corporation, an Ohio corporation Kankakee Scrap Corporation, an Illinois corporation Kimerling Acquisition Corp., a Delaware corporation Mac Leod Metals Co., a California corporation Metal Management Arizona, Inc., an Arizona corporation Metal Management Gulf Coast, Inc., a Delaware corporation Metal Management Pittsburgh, Inc., a Delaware corporation Metal Management Realty, Inc., an Arizona corporation Michael Schiavone & Sons, Inc., a Delaware corporation Naporano Iron & Metal Co., a New Jersey corporation Newell Recycling West, Inc., a Colorado corporation NIMCO Shredding Co., a New Jersey corporation 138 Scrap, Inc., an Illinois corporation PerlCo, L.L.C., a Tennessee limited liability company P. Joseph Iron & Metal, Inc., an Ohio corporation Proler Southwest Inc., a Texas corporation Proler Steelworks L.L.C., a Delaware limited liability company R&P Holdings, Inc., a Delaware corporation Reserve Iron & Metal Limited Partnership, a Delaware limited partnership Salt River Recycling, L.L.C., an Arizona limited liability company Scrap Processing, Inc., an Illinois corporation Torrington Scrap Company, a Delaware corporation Trojan Trading Co., a California corporation USA Southwestern Carrier, Inc., an Arizona corporation