Narottam Saha

Mining and mineral processing generate very large volumes of chemically reactive waste, from highly alkaline bauxite residue to acid-forming sulfidic waste rock. Managing these wastes is costly and can leave pollution liabilities for decades. Dr Saha's research develops rehabilitation approaches that work with natural soil- and rock-forming processes, so the wastes themselves become part of the nature-based solution.

Ecological Engineering: turning bauxite residue into soil

Alumina refineries worldwide have accumulated more than 4 billion tonnes of alkaline and saline bauxite residue, and covering it with imported topsoil is expensive and often impractical. Dr Saha's research transforms this residue into functional, soil-like growth media, an approach being validated through long-term, industry-partnered field trials. It offers a pathway to self-sustaining vegetation on residue disposal areas, reduced reliance on imported topsoil and conventional capping, and lower risk of contaminant release to surrounding land and water.

Engineered Mineral Stabilisation: turning acid-forming and alkaline wastes into rock-like geo-structures

Acid and metalliferous drainage from sulfidic waste rock can pollute waterways for decades after a mine closes, and alkaline residues pose their own long-term risks. Relocating or covering large waste deposits is expensive. This research develops technologies that cement and encapsulate alkaline and acid-forming mine wastes in place, emulating natural rock formation to limit water and oxygen movement and immobilise contaminants. Progressing from laboratory validation towards field-scale application, these technologies aim to prevent acid and metalliferous drainage at source, repurpose industrial wastes as rehabilitation materials, and reduce long-term water treatment needs and closure liabilities.

From research to practice

Dr Saha works with Queensland Alumina Limited, Rio Tinto and Agnico Eagle to translate this research from laboratory experiments to field trials, supporting mine closure solutions that protect the environment, reuse industrial wastes and support stable post-mining landforms.