Senior U.S. District Judge Stephen M. McNamee has rejected ASARCO LLC’s request for reconsideration of his March 3 decision to enforce an arbitrator’s award to pay a negotiated quarterly bonus to hundreds of employees hired after June 30, 2011. The bonus fluctuates based on the price of copper, and the arbitrator decided that the company breached the parties’ agreement in withholding its payment to these employees.

The unions, which represent more than 2,000 workers at five ASARCO locations in Arizona and Texas, won the arbitration against the Grupo Mexico subsidiary in December 2014, and the award is now estimated to be worth more than $10 million.

In addition to rejecting ASARCO’s arguments for reconsideration, Judge McNamee has ordered the company to pay post-judgement interest on the arbitrator’s award, dating back to the March 3 decision.