Los Mineros has withdrawn its challenge to be the legal union for workers at Torex Gold’s El Limon-Guajes gold mine in Mexico’s Guerrero state.

A fight over union representation led to a months-long worker blockade at the mine, which forced a project shutdown in December. A group of workers claimed the union representing them, the Confederacion de Trabajadores de Mexico (CTM), is illegitimate. They wanted to join Los Mineros, a more independent Mexican union with ties to Canadian unions. The shutdown ended in late January, when the state governor removed the blockade.

The CTM is the largest alliance of unions in Mexico and has faced criticism for taking the side of companies rather than employees. Torex selected the CTM before operations began at El Limon-Guajes, forming an “employer protection contract” with the union. Mexico legally recognizes so-called “protection unions,” but labour advocates like Canadian unions Unifor and the United Steelworkers argue they prevent workers from organizing on their own, and don’t provide the normal benefits of union members.

Related: Labour disruption at Torex's El Limon-Guajes mine highlights controversial Mexican “protection unions”

The Los Mineros withdrawal terminates what had been an ongoing government-sanctioned union selection process and leaves the CTM the default choice for mine employees.

“Torex has always supported the legally sanctioned, democratic union selection process,” Fred Stanford, Torex’s president and CEO, said in a press release.

“We see this Los Mineros union withdrawal from the union selection process as a tacit acknowledgement that the incumbent CTM union has the support of the majority of union-eligible employees,” he added.