TUCSON, Ariz. – A Grupo Mexico subsidiary has filed a bankruptcy reorganization plan seeking to regain control of copper producer Asarco LLC, based in Tucson, U.S. Bankruptcy Court documents show.

Americas Mining Corp., a subsidiary of the conglomerate headquartered in Mexico City, filed its proposal Tuesday in U.S. Bankruptcy Court in Corpus Christi, Texas.

AMC's proposal would make up to $2.7 billion in cash available and also offer a $440 million guarantee that all allowed creditor claims would be paid, including payment of liabilities relating to asbestos and environmental claims.

On July 31, the state of Montana announced a $143 million agreement with Asarco for environmental cleanup, much of it for contamination in East Helena, where the company for a century operated a now defunct lead smelter.

Montana Attorney General Mike McGrath said the agreement, subject to approval in U.S. Bankruptcy Court, would provide $100 million to clean up contaminated soil and groundwater in East Helena, and money to address mining contamination at Asarco property elsewhere in the state.

Asarco filed for bankruptcy protection in 2005. It wants the court to let Sterlite Industries Ltd. of India purchase Asarco's operating assets. Asarco would then pay outstanding environmental claims and creditors itself.

Asarco puts the onus for its financial difficulties and bankruptcy on Grupo Mexico. The company does not want to be put under control of Grupo Beta again, which bought Asarco in 1999.