I've seen two of his fights against Alfredo Layne and Tony Lopez (rematch).
He won the title from Panamanian Alfredo Layne who stopped the great Wilfredo Gomez one fight before this one. Mitchell applied grinding pressure that eventually broke Layne down flooring him multiple times in the tenth round.
In the Lopez rematch, he boxed beautifully rolling and weaving under Lopez' shots coming up with his own perfectly timed left hooks and constantly peppering Tony with jabs. Their first fight was a controversial draw. It was held in Lopez' hometown of Sacramento but Mitchell being the true road warrior he was fought him again in Sacramento and thoroughly outclassed him.
Due to apartheid the WBA wouldn't allow him to defend his title in South Africa so he had to fight in the other guys backyard which explains his two draws to Lopez in Sacramento and Joe Rivera in Puerto Rico. He did take some non title matches in South Africa during his title reign.
Has the Junior Lightweight record of 12 title defenses.
He defended his title in the following countries: Puerto Rico,Panama,France,Spain,United Kingdom,USA and Italy 5 times.
He should have been in the hall years ago but it's always better late than never. A true great.