Another addition from the Nou Camp, midfielder Andre Gomes, joined on a season's loan.
He has played 14 times for Brazil, scoring once, with his last worldwide appearance coming at the 2014 World Cup.
Mina had been strongly linked with a move to Manchester United following an impressive 2018 World Cup with Colombia, but Everton secured his signature.
The transfer window remains open in Spain until the end of August and closes in Italy on 17 August.More news: Bill Schuette and Gretchen Whitmer Win Michigan Gubernatorial Primary Races
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Gomes and Mina could be registered in time to face Wolves in the Premier League opener this Saturday, but that game may come too soon for them as they look to bed in at Everton. Everton will pay 2.6 million euros for the year's loan. Further details are yet to emerge, including if there is a permanent purchase option included in the deal.
Manchester United and Lyon had both tracked Colombia worldwide Mina, who signed a five-year deal after Barca sanctioned his £27.2 million sale.
Barcelona have been trying to offload the duo all summer and it seems they will be able to succeed by the transfer window slams shut in England at 5pm.
A loan fee of around £2million was agreed, with Everton also picking up the cost of the player's wages. However, Everton have taken a march over many other reported targets and sealed the deal for Barcelona's unwanted man.