SANTIAGO – Anglo American is restarting operations at its Los Bronces copper mine in central Chile following a brief but violent protest by contract workers, a spokesperson told Reuters early Tuesday.

"Shift workers are already going up to the mine to be able to restart operations," said Marcelo Esquivel, Anglo American's spokesperson in Chile.

The mine should be operating normally by the end of the day, he said, adding there was no estimate of how the stoppage had hurt production. A Chile-based trader said the stoppage had been too brief to impact the market.

Los Bronces, perched high in the Andes near Santiago, produced 416 300 t of red metal last year, roughly 7% of world No 1 copper producer Chile's overall output.

In the early hours of Monday, contract workers launched a protest over what they claim are layoff threats and the London-listed miner's refusal to negotiate a series of demands. A union representative said workers turned to violence because their demands hadn't been listened to.

The demonstrators set tyres on fire, damaged installations and looted during the protest, according to Anglo. The protests ebbed on Monday night, allowing Anglo to restart operations.

Contract worker representatives and Anglo American are negotiating, a spokesperson for the CTC mining union told Reuters on Tuesday.

He said there was interest in clinching a deal, but that launching fresh labour action remained on the cards if an agreement proves elusive.

The labour action highlights growing tensions with contract workers, who are usually paid less than their staff counterparts for similar work, at a time when Chile's mining boom is losing steam.

Anglo owns 50.1% of the deposit. Chilean state miner Codelco and Japanese trading houses Mitsui & Co and Mitsubishi Corp also have stakes in the complex.

Copper didn't appear to react strongly to the brief stoppage.

Prices rose to the highest level in nearly a week on Tuesday, supported in part by prospects that big commodities consumer China will act to support its slowing economy, and ahead of key US data later in the session.

Still, the Chile stoppage "also appear to have helped lend copper some support," analyst Leon Westgate at Standard Bank wrote in a note to clients.