(Adds details on other operations, Antofagasta's comments, impact on copper prices, background)
By Anthony Esposito and Fabian Cambero
SANTIAGO, Sept 17 (Reuters) - Chile's Codelco said on Thursday it restarted its open-pit Andina mine located in the Andes mountains, as mining operations in the world's top copper producer appeared to be unscathed after a powerful earthquake that struck off the coast overnight.
Earlier on Thursday, the state-run copper miner reopened its Ventanas refiner and smelter, which was evacuated as a precautionary measure after a magnitude 8.3 earthquake slammed the South American nation on Wednesday night.
The seismic shock killed eight people, forced more than 1 million from their homes and caused flooding and power outages in central Chile.
After early morning inspections, Chile's copper mines appeared to be unscathed.
"Operations in the open-pit mine restarted at 10:00 a.m. local time," Codelco said about Andina, located some 80 km (50 miles) northeast of the capital, Santiago.
Antofagasta Plc said it was inspecting operations at its flagship Los Pelambres copper mine and expects to progressively restart operations in the coming hours.
Andina and Los Pelambres produced a combined 600,000 tonnes of copper last year, which is about 3 percent of global capacity.
Antofagasta's port infrastructure in the coastal city of Los Vilos was not damaged by the quake and ensuing tsunami waves and the Los Pelambres' tailings dam was also undamaged, it said.
The company reiterated that none of its workers was injured in the natural disaster.
The latest natural catastrophe to hit Chile, which accounts for a third of the world's copper supply, sent three-month copper prices to two-month highs of $5,440 per tonne in early Asian trading.
By 10:28 a.m. EDT (1428 GMT), prices were off those high levels, but up 0.46 percent at $5,402 per tonne, as concerns about long-term disruptions subsided.
Writing by Josephine Mason in New York; editing by Chizu Nomiyama and Marguerita Choy