Mr Rios was employed at the Araxá operations of CBMM from 1996 to 2020, working in several roles including senior leadership positions in mineral processing and mining operations culminating in the Mineral Production Senior Management position responsible for seven departments. Key functions at CBMM included management of mineral processing systems, metallurgy analysis, product innovation, offtake specification, utilities and mine operations.

Mr Rios was appointed by CBMM to serve from 2018 to 2020 as Director of Operations at COMIPA, the mining joint venture between CBMM and CODEMIG (the mining company owned by the State of Minas Gerais) that handles most of the niobium and REE mining at the Barreiro Carbonatite.