SANTIAGO, June 1 (Reuters) - The union of workers at BHP's Escondida copper mine in Chile said on Friday it had kicked off the latest round of labor negotiations with a contract proposal that includes a bonus of about $34,000 per worker at the world's largest copper mine.
The closely-watched talks come little more than one year after failure to reach a labor deal at the mine led to a 44-day strike that jolted the global copper market.
"For us, this negotiation is the continuation of the same fight for dignity that we began last year, an effort to defend our benefits and our rights," the union said in a statement.
The price of copper on the London Metal Exchange has risen more than 50 percent since hitting a nine-year low in 2016, boosting profits globally and potentially providing unions more leverage in negotiations.
The union has demanded a one-time bonus equivalent to 4 percent of dividends distributed to shareholders in 2017, or about $34,000 per worker. The union also requested a 5 percent increase in salaries for its workers.
"We believe that (the bonus) is proportionate and fair," the union said.
BHP said in a statement that it would review the proposal and prepare a response within 10 business days allowed by law.
Workers at the mine last year decided to end the strike by invoking a legal provision that allows them to extend their existing contract by 18 months, through July 31, 2018.
The two parties again failed to reach agreement in early talks in April.
The Anglo-Australian miner has until mid-June to respond to the union's demands.
Direct talks between the union and the company are slated to begin in July.
(Reporting by Fabian Cambero, writing by Dave Sherwood; Editing by Marguerita Choy)