Mexico mining union to hold strike despite threat

MEXICO CITY, April 25 (Reuters) - Mexico's mining union rejected on Friday liquidation offers for workers at one of Latin America's biggest copper mines, decrying efforts to shut the pit and end an eight-month-long strike.

Workers walked off the job last July at Grupo Mexico's (GMEXICOB.MX) massive Cananea mine in northern Mexico over health and safety concerns, crippling copper production. A personal fight between the union's leader, now living in Canada, and the company has prolonged the labor battle.

The company sent a letter to workers this week saying the mine was effectively closed and offered higher severance packages to those who chose to leave their jobs, the union said.

"They are threatening to close the mine, but they can't do that," union official Carlos Pavon told Reuters. "They are offering people liquidation packages but no one is accepting them," he said.

A similar letter was sent at the beginning of the month to miners at the San Martin silver-zinc mine, also owned by Grupo Mexico, and paralyzed by the strike.

"Because of this situation the company has no other option but to shut the unit down," said a Grupo Mexico letter sent to the San Martin workers. The pit is smaller and had only a few months left of mineral reserves, said the company.

Grupo Mexico's Taxco silver mine was also closed last year because of the strike.

But the union says it is illegal to fire workers or close a mine in the middle of an ongoing labor dispute.

A back-and-forth legal battle -- where a government labor board usually sides with the company and courts tend to agree with union appeals -- has failed to determine the strike's legality.

In January, the labor board ruled the strike illegal and Grupo Mexico retook control of Cananea after a brief clash between union members and police. The company was slowly trying to retune equipment left idle for months and ramp up production.

But Grupo Mexico's goal of having significant copper production by May has been stalled by new blockades. (Reporting by Mica Rosenberg; Editing by Marguerita Choy)