Workers at the Escondida copper mine in Chile rejected BHP Billiton Group's final contract offer and agreed to vote on a strike, Reuters reported July 28, citing an internal union document.

The new negotiations, which began in June, centered on a contract proposal that includes a one-time bonus of about US$34,000 per worker, equivalent to 4% of dividends distributed to shareholders in 2017, as demanded by the union. The group also asked for a 5% wage increase.

The vote on a strike was set to begin July 28 and will continue through the middle of the week of July 30.

BHP's final offer included a signing bonus of US$27,700, from an initial US$23,000 bonus, and a salary adjustment linked to inflation. The offer, valued at about 18 million Chilean pesos, was less than the 23 million pesos workers received under the 2013 negotiations.

In 2017, workers downed tools in a 43-day strike, in which the union decided to invoke article 369 of the country's labor code to end the stoppage. The provision halted and postponed wage negotiations, extending the previous contract for 18 months while maintaining current benefits.

In April, both sides started early talks on a new collective contract, which ended in a stalemate.

As of July 27, US$1 was equivalent to 642.89 Chilean pesos.