Spanish police have raided six Bitcoin mining centers across the country, arresting 30 people on money laundering charges.

The arrests in Madrid, Barcelona, Valencia, and Cordoba followed an investigation by the country's tax agency.

Reuters reports the operators were laundering cash obtained from pay TV piracy.

Some €31,320 (A$54,150, US$38,930, £26,480) of Bitcoins were seized, along with cash and luxury goods.

Police said the bitcoin mining facilities were using "vast" amounts of electricity.

Bitcoin mining facilities have exploded in popularity in recent years. The farms range in complexity from dirty shacks in regional China to high tech hubs in Hong Kong. ®