Archaeologists have discovered an iron oxide mine from 12,000 years ago in northern Chile, making it the oldest mine yet discovered in all the Americas, the El Mercurio daily says.

The iron oxide mined by the Huentelauquen Indians was used as a pigment in dying cloth and in religious rituals, revealing an unexpected sophistication in what was previously considered a primitive group of people, University of Chile researcher Diego Salazar said on Sunday.

"The fact they developed a mine shows the importance religion had in their lives, because iron oxide was not used as food, was not bought or sold," he told the daily.

The ancient mine was discovered near the town of Taltal, in the Antofagasta region, 1,100km north of Santiago, in October 2008, but its antiquity was not determined until tests were conducted this year in US and Polish laboratories.

Named "San Ramon 15", the mine was exploited heavily between around 10,000 BC and 2,000 BC. It yielded over the millennia a total of 2,000 tonnes of pigment extracted from 700 cubic metres of rock.

Researchers also found a treasure trove of stone and conch mining tools in the area.

"We've found more than 1,000 hammers ... but considering the amount of material we have yet to sift through, the real number could rise to several thousands," said archaeologist Hernan Salinas.

Before this find, the oldest mine in the Americas was 2,500 years old and located in the United States. The world's most ancient mine is in South Africa and is about 40,000 years old.