More than two tonnes of ancient coins dating back to as early as the Tang Dynasty (618-907) have been unearthed on a playground of a primary school in Shaanxi Province, northwest China.

Zhao Aiguo, director of the cultural relics protection and tourism bureau in Liquan County, Shaanxi, told Xinhua Wednesday that the coins were found when workers were excavating the grounds Tuesday for construction of another building.

They reported their discovery to the bureau and soon more than 70 archaeologists, officials and police were sent to the site.

It took more than five hours to dig the ancient coins out of a vault made of grey bricks.

Zhao said they were in circulation for more than 750 years during the Tang, Song (960-1279) and Yuan (1279-1368) Dynasties.

The vault measures 1.5 meters in width and length and one meter in height. It is believed to have been built during the Yuan Dynasty.

The coins have been sent to a local museum and archaeologists were counting them. Because there were so many, it might take a week to know the exact number and categories, Zhao said.

The site of the discovery was part of a temple built by an ancient emperor in memory of his mother between 180 BC and 157 BC. Zhao cited archaeologists as saying that the coins might be donations from believers who visited the temple.

In 2006, archaeologists in the same province discovered an ancient tomb, possibly of a coin collector, dating back more than 600 years. It contained more than 150 coins of 20 kinds from the Tang, Song and Jin (1115-1234) Dynasties, spanning about 600 years.

(Xinhua News Agency June 11, 2009)