UPDATE 1 — No breakthrough in talks at Antofagasta's striking Centinela copper mine, unions say

(Adds company statement) SANTIAGO, Oct 15 (Reuters) — Negotiations between Antofagasta Minerals and two striking unions at Chile's Centinela copper mine showed no progress on Thursday, while three workers marked their seventh day on a hunger strike. The Distrito Centinela and Minera Esperanza unions, which together represent more than 700 workers, began the walkout on October 7 after contract talks collapsed. The sides returned to the negotiating table on Tuesday in an effort to resolve the dispute. "So far, after three days of voluntary mediation, the company has refused to address a mechanism to end discrimination during the term of the collective agreement," the unions said in a statement. The unions added that the company was continuing to present a financial offer already rejected by workers, while ignoring what they called the core issue: alleged violations of workers' fundamental rights to equal treatment and non-discrimination. The unions say the dispute centers on alleged disparities in pay and benefits for workers performing similar roles at the mine. Antofagasta said on Wednesday that it had so far managed to keep production running as planned. On Thursday, the company r