The AIM and TSX-listed company has started the permitting process to develop a solar plant at the mine near Seville.
The full capacity of the plant will be used for self-consumption.
Technical studies carried out by a third party during the past months have indicated that, in addition to making a significant contribution to reduce carbon emissions, the solar project is economically viable and could potentially contribute to reducing Proyecto Riotinto's operating costs, Atalaya said.
During the permitting period, the company will evaluate the various financing options that are being proposed by industry players in Spain.
Subject to completing the permitting process and securing financing, construction is targeted to start by mid-2021.
Chief exceutive Alberto Lavandeira said: "We are pleased to be committing to this solar initiative which will be one of the largest projects of renewable self-consumption in the industry. This is only a first step in achieving our long-term sustainability goals, but one that will have a positive and near term impact on Proyecto Riotinto."