Rio Tinto

This technical memorandum summarizes conceptual level sampling locations, sampling frequency, and laboratory testing to be conducted on tailings and the associated decant pond.

Predictions of the chemical compositions of tailings porewater and seepage during the mine’s operation and after closure is the focus of this document.

Rio Tinto reported a strong set of results with operating cash flow of US$13.9 billion, a record full year dividend of US$5.2 billion and an additional US$1 billion share buy-back. This brings total cash returns to shareholders to US$9.7 billion declared for 2017.

The Safety standard D5 - Management of tailings and water storage facilities (the standard) applies to all Rio Tinto projects, business units and managed operations, including new acquisitions. It covers all development phases from planning, design through construction, operation, closure and, post-closure where applicable.

Resolution will implement best practice, proactive acid rock drainage (ARD) management strategies. The goal of these strategies will be to minimize ARD risks during operation and ensure that ARD is avoided after closure.