| ANTOFAGASTA, Chile
ANTOFAGASTA, Chile Workers at BHP Billiton's (BHP.AX) (BLT.L) Escondida copper mine in Chile, the world's largest, walked off the job on Thursday in a strike that threatens to disrupt the international supply of the widely used metal.
It said no miners arrived for morning work aboard buses that normally carry upwards of 1,200 workers per shift to the vast deposit, which accounted for about 6 percent of global production in 2015.
The striking workers are building a campsite right outside the mine. The union has warned it is prepared for a lengthy strike, saying it has stockpiled supplies and provisions for 60 days. Escondida's processing plants, which had begun going offline on Wednesday, have completely stopped, the union said.
"If someone suddenly walked into your kitchen and took away your refrigerator, would you just stand there, arms crossed?" asked miner Jose Alcaino, after returning from the night shift.
"That's what's happening here. They want to take away our benefits, our money, they want to work us more."
BHP said in a statement on Thursday it was focused on maintaining "minimum services" at the mine, which typically consist of small teams of workers maintaining upkeep of equipment and making sure the mine adheres to environmental protocols.
The company also said it was continuing work on new construction projects, such as expansions at a concentrator and a desalination plant.
It previously said it will not produce copper during the strike.
At a makeshift camp near the entrance to Escondida, which is partially owned by Rio Tinto (RIO.L) (RIO.AX) and Japan's JECO (7768.T), protesting workers settled in throughout Thursday, equipped with stockpiles of gas cylinders, portable cookers and tents to weather the Chilean high desert's scorching sun and frigid nights.
The camp on a windy, barren plateau between the surrounding mountains was abuzz with chatter and the sound of hammers hitting nails as some workers began constructing semi-permanent structures out of wood.
Among the issues pitting the 2,500-member Escondida No. 1 Union against the company are the distribution of benefits. Workers complain that BHP wants to cut benefits and has not committed to a benefits scheme that places new and longtime employees on equal footing, something the union considers essential.
Striking workers also blocked roads at the Coloso port near the dusty city of Antofagasta, where hundreds of thousands of tonnes of copper are shipped annually.
"We are united and strong to make sure this is a success," said Claudio Perez, plant worker at Coloso.
Fears of the strike had sent copper prices soaring in recent weeks. Prices for the red metal, however, eased on Thursday as some investors cashed in the previous day's gains.
Labor negotiations at Escondida, which are seen as a benchmark for the industry at large, have long history of being contentious.
About a decade ago workers staged a now infamous 26-day strike that forced the global miner to declare force majeure on copper shipments. A labour conflict in 2011 paralysed the mine for two weeks.
The last wage talks, which occurred four years ago when copper prices were 42 percent higher than now, ended with the company offering each worker a bonus of $49,000, the largest in Chilean mining history.
This time around the union has asked for a 7 percent salary increase and a $39,000 bonus.
Industry analysts are watching the developments at Escondida closely, as they could be a precursor of upcoming labour talks at other mines.
Glencore Plc (GLEN.L) and Anglo American's (AAL.L) Collahuasi is one of several copper mines in Chile due for contract negotiations this year.
(Additional reporting by Anthony Esposito & Gram Slattery; Writing by Anthony Esposito & Gram Slattery; Editing by Grant McCool and Matthew Lewis)