The mining company involved in a deadly dam burst last year says its president and head of operations are temporarily stepping aside.

Samarco said in a statement Wednesday that president Ricardo Vescovi and operations head Kleber Terra asked to leave to prepare their defense.

The executives have been indicted and Samarco is facing billions of dollars in fines stemming from the Nov. 5 dam burst at an iron ore mine in the central state of Minas Gerais.

At least 17 people were killed when a massive wave of mining debris all but erased a nearby hamlet. The mud polluted hundreds of miles of waterways in two states in southeastern Brazil, devastating wildlife.

Samarco is a joint-venture of mining giants Vale and BHP Billiton.