NEW DELHI: As India advances its climate goals, the demand for critical minerals is set to soar. However, with traditional mineral sources depleting and new deposits becoming harder to access, reprocessing mine tailings offers a sustainable alternativeโaddressing environmental concerns and optimizing land use.
A report jointly authored by FICCI and Deloitte explores the potential for recovering critical minerals from mine tailings and overburden in India.
Examples from Canada and the USA highlight the vast economic potential within mining waste, with billions of dollarsโ worth of recoverable metals identified.
Recognizing this, Indiaโs 2025 Union Budget has introduced a policy to promote critical mineral recovery from mine waste, emphasizing sustainable resource utilization.
Natural Resources Canada estimates that gold mine waste alone holds an untapped metal value of nearly US$10 billion.
In the Mojave Desert, a major mining company has identified lithium deposits in concentrations higher than those found in many new development projects across the U.S.
Additionally, research indicates that coal ash deposits in the U.S. contain REEs worth approximately US$8.4 billion.
India, too, has vast reserves of fly ash, red mud, mine overburden, and tailings that hold significant potential for critical mineral recovery.
Fly Ash: A Hidden Resource for REEs
India generates around 245 million tonnes of fly ash annually from thermal power plants, a figure expected to triple by 2030.
Traditionally considered waste, fly ash contains REEs essential for industries such as defense, renewable energy, and high-tech manufacturing.
Recent breakthroughs in extraction technologies are driving new opportunities. A U.S.-based company has developed an eco-friendly process using ionic liquids to extract REEs from coal fly ash with minimal waste.
In India, a premier research institute has successfully produced REE-rich iron hydroxide from fly ash, attracting interest from power companies and policymakers.
Red Mud: A Byproduct with Untapped Value
Red mud, a byproduct of the bauxite refining process, contains iron, titanium, vanadium, and REEs. India generates about 9 million tonnes of red mud annually, most of which remains unused.
The Council of Scientific and Industrial Research (CSIR) has initiated research collaborations with top metallurgical institutes and leading aluminum producers to develop commercial methods for extracting valuable minerals from red mud.
Mine Overburden: A Source of Nickel and Cobalt
Indiaโs mine overburden, consisting of low-grade ore and waste rock, is another overlooked resource. Chromite mining in Odishaโs Sukinda region generates substantial overburden containing nickel and cobalt, two essential minerals for battery production.
In 2024, Indiaโs chromite production stood at 4.1 million tonnes, with significant untapped potential for secondary resource recovery.
Tailings and Metal Slag: Potential for Secondary Mining
Globally, an estimated 16 billion tonnes of tailings are generated annually, adding to a stockpile of nearly 282 billion tonnes. Many older tailings contain economically viable amounts of copper, cobalt, nickel, and lithium.
In India, efforts are underway to explore mineral recovery from gold mine tailings at Kolar Gold Fields in Karnataka.
Metal slag, a byproduct of refining metals like copper, zinc, and lead, is another potential source of critical minerals.
A lead-zinc producer in Rajasthan has successfully recovered cobalt from its smelting residues and is exploring further opportunities in metal recovery.
Challenges and Opportunities in Mine Waste Recovery
Despite its promise, several challenges remain in extracting critical minerals from mine waste. Technical hurdles include low mineral concentrations, the presence of impurities, and the need for advanced processing techniques such as bioleaching and hydrometallurgy.
High energy costs and environmental concerns, including hazardous waste generation, also pose significant obstacles.
However, the benefits outweigh the challenges. Reprocessing mine waste reduces land degradation, mitigates environmental risks, and creates employment opportunities.
Successful international projects demonstrate that mineral recovery from tailings can revive mining regions, enhance community relations, and drive economic growth.
