UPDATE 1-Grupo Mexico makes $1.55 bln offer for Asarco

*Grupo Mexico files reorganization plan for Asarco

*Grupo offers $1.6 billion

*Grupo says has support of asbestos creditors

By Emily Chasan

NEW YORK, May 15 (Reuters) - A Grupo Mexico SAB de CV(GMEXICOB.MX) unit on Friday formalized its $1.55 billion offer for bankrupt U.S. copper miner Asarco LLC by filing its own proposal for Asarco's reorganization in a Texas court.

Grupo Mexico, which acquired Asarco in a leveraged buyout in 1999, but lacks board control of the company due to the bankruptcy, is competing against a $1.7 billion offer from India's Sterlite Industries (STRL.BO).

Both potential buyers have now filed their own reorganization plans with the bankruptcy court.

Grupo Mexico said it is offering $1.3 billion in cash and a $250 million fully committed loan to regain control of Asarco. Sterlite's offer is for $1.1 billion in cash and and about $600 million of senior secured notes, payable over nine years.

"We look forward to the Court's decision in this process and to regaining control of our subsidiary," Alberto de la Parra, General Counsel of Grupo Mexico said in a statement.