Tucson-based Asarco

Asarco operates the Mission Mine in Sahuarita, among others.

A federal judge has ruled again that Tucson-based copper miner Asarco LLC must pay millions of dollars worth of copper-price bonuses to union employees in Arizona and Texas.

In a ruling filed Tuesday, Judge Stephen M. McNamee of the U.S. District Court in Phoenix denied Asarco’s motion to reconsider his March ruling that an arbitrator acted properly in ordering Asarco to pay the bonuses.

Asarco, part of Mexico-based mining giant Grupo Mexico, had alleged in a federal lawsuit filed in January 2015 that an arbitrator exceeded his authority by ordering the company to pay a quarterly copper-price bonus to union employees who are not part of the company’s pension plan.

Asarco’s unions, led by the United Steelworkers, won the initial arbitration award in December 2014. The unions represent more than 2,000 workers at five Asarco locations in Arizona and Texas.

McNamee also ordered Asarco to pay post-judgment interest on the amount awarded by the arbitrator — now estimated to be worth more than $10 million — dating to the March 3 decision.

The bonus issue affects about 550 Asarco employees hired after June 30, 2011, and still employed as of March 2015, as well as 180 former hourly employees who were either terminated, on leaves of absence or were promoted to salaried employees, according to court documents filed by the unions and attributed to Asarco.

The documents show miners are owed individual amounts ranging from about $1,100 to more than $30,000, with the average owed about $13,000.

Asarco did not immediately respond to a request for comment.

Steelworkers District 12 Director Robert LaVenture said in a news release that Asarco “needs to stop using legal shenanigans and pay its union workers what they are owed.”

Asarco operates the Mission Mine in Sahuarita south of Tucson, the Silver Bell Mine in Marana, and the Ray Mine and Hayden smelter in Central Arizona.

In a separate case pending before the National Labor Relations Board, the NLRB accuses Asarco of unfair labor practices including implementing portions of its “last, best and final” contract proposal, failing and refusing to bargain, unilaterally changing working conditions and other violations of federal labor laws.

Hourly employees represented by eight international unions have continued to work at Asarco facilities under the terms of a labor agreement that originally expired in June 2013, but was extended until the parties terminated it in June 2015.

Reporter

David joined the Star in 1997, after working as a consumer and business reporter in Phoenix for more than a decade. A graduate of Ohio University, he has covered most business beats focusing on technology, defense and utilities. He has won several awards.