Labor tensions at the world’s biggest copper mine are no longer restricted to relations between union and management.

A group of workers trying to set up a new union at BHP Billiton Ltd.’s Escondida in Chile say they are being intimidated and insulted by members of the existing union, showing how much is at stake in wage talks set to to resume in June.

The existing union, known as Union No. 1, held talks with management last year that led to the longest mine strike in modern Chilean history and failed to yield an accord. The breakaway group needs to convince at least 10 percent of the 2,500-strong workforce to join by Feb. 8 in order to hold separate wage talks with the company.

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Union No. 1, which declined to comment for this story, said in a statement on its website that the breakaway group contains individuals who respond directly to management and want to erode worker unity. Marcelo Fonseca, who is leading the breakaway efforts, describes the current union leadership as “disastrous.”

"More than a 1,000 workers have been fired under their watch and the 44-day strike was an economic disaster for a majority of workers," he said in a telephone interview Friday.

Fonseca said Union No. 1 leaders stood in front of the labor authority’s headquarters to watch which workers went in to sign up for the new union. He also filed a complaint with labor authorities after allegedly being the target of threatening language by union members.

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Union No. 1 declined to comment on those allegations. BHP’s Chile office didn’t respond to requests for comment.

Fonseca said he and other leaders of the initiative have been repeatedly called "chicken," the Chilean mining industry equivalent of "scab.” During last year’s strike, workers camping at the mine’s entrance built a chicken coop. Inside, they placed a list of names of the workers that didn’t join and hung a dummy of Escondida Corporate Affairs Vice President Patricio Vilaplana.

Fonseca said he was encouraged by about 100 people signing on to the new union on the first day. "However, anti-union attitudes by Union No. 1 members could impact our numbers."

The tensions between workers are building as the Chilean copper industry enters its busiest year ever for wage negotiations, raising the specter of more supply interruptions that last year helped push up metal prices.

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Updates with further comment by breakaway group in eighth paragraph.

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