MADRID, Sept 14 (Reuters) - Spain's nuclear watchdog CSN has...

MADRID, Sept 14 (Reuters) - Spain's nuclear watchdog CSN has asked Australian mining company Berkeley Energia (BKY) for more information on its plans for a uranium mine in Salamanca, on which work is due to begin later this year, the regulator said on Friday.

The project, which would become the European Union's only open-cast uranium mine if given the go-ahead, has faced local opposition since it was proposed and granted preliminary approval in early 2013.

Berkeley reiterated its confidence in the project on Friday after the CSN said it had requested more information in July.

"The Retortillo mine will very soon be a reality, generating investment of more than 250 million euros and more than 2,500 direct and indirect jobs in the region," Berkeley said in a statement, adding that it had already sent back the information requested by the regulator.

A spokesman for the CSN declined to say whether the information sent by Berkeley had already been looked at, or to make any further comment.

A neighbouring mine run by the public company ENUSA was previously in operation near the site in Retortillo in the Salamanca province, but was closed in 2000 after it failed to turn a profit.

Berkeley, which has a triple listing in Britain, Spain and Australia and operates no other projects, has insisted the mine can be profitable since conducting initial studies in 2007.

In a study presented to Australian investors Berkeley said the mine is capable of generating strong, sustainable cash flow. It said work would begin in 2018 and the mine would run for 14 years.

The potential environmental and social cost of the mine both during its operation and after its closure must be taken into account, the CSN said in its request for information.

Once the CSN has concluded its own study, the project must be cleared at a local and regional level and must also be given the go ahead by the national government. The project is also likely to need further authorisation from Brussels.