(Adds comments from Grupo Mexico, brokerage comment, paragraphs 3, 4, 9, 11)

NEW YORK, Feb 5 (Reuters) - Asarco LLC, the bankrupt copper mining company owned by Grupo Mexico (GMEXICOB.MX: Quote, Profile, Research), asked a U.S. court this week to approve a bidding process for six potential suitors to buy its assets.

Asarco, which owns three copper mines in Arizona, proposed a series of bid procedures that "will serve to procure the highest offer for the assets of Asarco," it said in the filing made on Monday to the U.S. Bankruptcy Court in the Southern District of Texas.

Grupo Mexico, which does not have decision-making control over Asarco's board, told Reuters it was opposed to the sale. The company said it hopes a court will give it control over Asarco's board before any bids are made.

"We are opposed to the sale," said Juan Rebolledo, a Grupo Mexico spokesman.

Asarco, which entered bankruptcy in August 2005 because of massive environmental cleanup and asbestos claims, did not name the potential buyers in the filing.

However, Swiss firm Glencore, an Asarco creditor, previously said in court documents it was interested in joining a bid to purchase the assets.

Asarco said its adviser, Lehman Brothers, had been in discussions with the potential buyers since April 2007.

A hearing on the approval of the bid procedures is expected to take place on March 10 at the bankruptcy court in Corpus Christi, Texas.