The Hammers have confirmed that the former Aston Villa ace has signed a two-year contract at the London Stadium - which may surprise some given that there was previous speculation that he may be arriving on loan.
Shortly after the transfer of Mina to Everton, the loan deal of André Gomes also to Everton was made public.
The duo become the second and third players to swap Camp Nou for Goodison Park this summer, following Lucas Digne to Merseyside.
The 25-year-old described his spell with Barca as "a kind of hell" during a candid interview in March, adding that he does not "feel good on the pitch".
"I chose Everton because of all the things I had heard about Marco Silva and after speaking to him I was happy with what he said to me", the midfielder said. The Club reserves the right to buy back the player.
"He has experience of playing in the Champions League for Shakhtar Donetsk for the past five years and the fact he has 14 caps for Brazil is a further reflection of his quality".
Mina, 23, only joined Barca six months ago from Palmeiras, but coach Ernesto Valverde has not been convinced by him and the club have made a decision to take advantage of his increased value following an impressive World Cup.
Yellow Warnings Issued As Heatwave Grinds To A Halt
Ms Diamond said: "This means there is an increased likelihood of warmer-than-average temperatures and below-average rainfall". Bookmaker Ladbrokes said the United Kingdom could still see 35C at least once this week before the heatwave ends.
India vs England 2nd Test Day 1 live updates
He picked up five wickets and scored 97 runs to be decisive in the low-scoring contest at Birmingham. India batsmen need to produce a better show in the second Test to give a tough fight to England .
Emery set for baptism of fire as Arsenal host Man City
Arsenal signed Welbeck from Manchester United on deadline day as well in 2014 when Louis van Gaal chose to ship him out. Liverpool , buoyant after a close-season spending spree, host equally busy West Ham United on Sunday.
Over 500 hikers rescued on Bali's Lombok
Hundreds of people in Lombok have been left homeless and are staying in temporary camps amid continuing aftershocks. A Malaysian was among the dead, with another six citizens injured, the foreign ministry in Kuala Lumpur said.