(Adds comments from union)
By Fabian Cambero
SANTIAGO, Sept 29 (Reuters) - Chile's second-biggest copper mine Collahuasi, owned by Anglo American Plc and Glencore Plc, is planning to cut output by 30,000 tonnes, and with dozens of jobs on the line the mine's union said it is mulling how it will protest the move.
"In line with the stabilization of its operations that has been implemented in recent years, and considering the complex market scenario for commodities worldwide, (the mine) is restructuring its operations," said Collahuasi in a statement on Tuesday.
Reductions would affect the leaching plant and associated activities and take some 30,000 tonnes of refined copper annually out of the market, the company said, without specifying a timetable for the cuts.
It added that there would also be job losses. The company did not state how many, but Collahuasi union leader Jose Vergara told Reuters that the company had told them around 110 jobs would go.
However, he said the union had calculated that the losses would be closer to 200 positions.
"At the moment we are consulting with lawyers to decide the best way of protesting this, bearing in mind the rights of our workers who haven't been affected," he said.
The planned cut represents just 7 percent of the mine's output last year of 470,000 tonnes.
But the measures by a significant player in the world's top producing nation reflect deepening pain as copper's year-long rout hurts producers' margins and the industry faces its biggest test since the 2008 financial crisis.
Fears over economic growth in key consumer China have led commodities prices to tumble. The copper price has weakened around 20 percent this year, falling below $5,000 a tonne.
The six-year low in the price of copper, used in construction and wiring, has already led Glencore to suspend operations at two mining units in Africa, while in Chile, U.S.-listed Freeport McMoRan Inc is slashing output.
And the world's largest producer, Chile's state-run Codelco, has delayed important expansion projects.
As well as complicating plans for companies, the potential job cuts and falling income from copper have also created a headache for Chilean President Michelle Bachelet, at a time when she is struggling with sharply declining popularity.
Copper makes up over half the country's exports, and analysts are expecting an austerity budget from the government this week as it fights to balance the books.
Reporting by Fabian Cambero; Writing by Rosalba O'Brien; Editing by Marguerita Choy and Lisa Shumaker