MEXICO CITY–Mexican mining company Grupo Mexico SAB (GMEXICO.MX) expanded Thursday on its rationale for requesting a rehearing before the Delaware Supreme Court on a ruling that the company unfairly profited from a deal between two of its units, taking issue specifically with the sizeable lawyer fees awarded in the case.

In a filing with the Mexican Stock Exchange, Grupo Mexico said the $315 million it has been ordered to pay the plaintiffs’ lawyers is “totally disproportionate” with the $256 million that it figures would be paid to minority shareholders represented by those lawyers.

Such legal fees imply an unprecedented rate of $35,000 per hour, Grupo Mexico said.

A Delaware judge ruled last October that Grupo Mexico owes shareholders of Southern Copper Corp. (SCCO), the subsidiary that runs its Mexican and Peruvian mining operations, around $2.1 billion related to the 2005 merger of the company’s Mexican mining unit Minera Mexico and Southern Peru Copper, now Southern Copper Corp.

The judge said the merger deal overvalued the Mexican mining unit.

Grupo Mexico asked for a rehearing on Tuesday, after having lost an appeal on Aug. 27. The Delaware Supreme Court ruled 4-1 in August to preserve the lawyer fees, with Justice Randy Holland writing that the “challenge of quantifying fee awards is entrusted to the trial judge and will not be disturbed on appeal in the absence of capriciousness or factual findings that are clearly wrong.”

Grupo Mexico said Thursday that only 0.05% of voting shareholders opposed the 2005 deal, and accused the plaintiffs’ lawyers of having “self-promoted” the lawsuit. The suit was filed by law firms Prickett, Jones & Elliott and Kessler Topaz Meltzer & Check.

Lawyers with the plaintiffs’ firms were not immediately available to comment.

Since it owns over 80% of Southern Copper, Grupo Mexico calculates the net impact of the case at $399 million, a figure that would not significantly crimp Grupo Mexico’s financial position.

The company reported net profit of $2.47 billion for 2011, and earnings before interest, taxes, depreciation and amortization of $5.19 billion, on sales of $10.44 billion.

Grupo Mexico argues that the plaintiffs’ lawyers should receive a far smaller sum of $30 million, which would represent less than 15% of the award to minority shareholders after taking out Grupo Mexico’s stake in Southern Copper.

Grupo Mexico is one of the world’s biggest copper producers, with mines in Peru, Mexico and the U.S. It also runs two of Mexico’s principal railways.