Mines was an account director at Franklin Rae responsible for a large portfolio of clients across online, production, talent and music.
She is on Braben’s senior management team and will report to managing director Matt Bourn.
She will oversee a team of communication and content executives and a portfolio of clients across media, mobile, technology and advertising.
Mines has 15 years of consumer and broadcast technology comms experience, including four years working as a publicist for the BBC’s Future Media & Technology department.
Bourn said: ‘Sarah has a wealth of knowledge and skills which will perfectly complement our team as we deliver the specialist expertise, tools and skills our clients need to manage all levels of business communications.’