Fabio Schvartsman has been "temporarily" removed from his CEO's role.
Research points to 14 serious failures and so far there have been 11 in this decade.
Had already decommissioned nine by the time the Brumadinho disaster occurred last month.
Estimated to take three years and will stop production of 40 million tonnes per annum.
Company working on plan to improve the safety of its tailings dams.