It was unclear how or when the bonuses will be paid. Asarco officials did not respond to requests for comment on Monday.

Manny Armenta, subdistrict director for the United Steelworkers, said the union officials had not heard from the company regarding the bonus payments Monday, but Asarco provided and verified a list of affected workers a couple of years ago and the union will work to ensure they are paid.

Asarco, part of Mexico-based Grupo México, has been fighting to avoid paying the bonuses since 2014. That’s when an arbitrator decided that newer workers ineligible for the company’s pension plan should get the bonuses, because that provision was left out of a collective-bargaining agreement signed in 2011 due to a mutual mistake by the company and the unions.

Former Asarco employee David Larkin is hoping to collect thousands of dollars in back bonuses from the company after working as a truck driver at Asarco’s Mission Mine in Sahuarita from mid-2013 to early 2016.

Larkin, 62, who joined Asarco after retiring from the Tucson Fire Department after 29 years in 2011, recalls seeing quarterly bonus amounts of more than $4,000 per worker posted at work and then being told he wasn’t eligible.