Every day, thousands of tonnes of coal roll out of Odisha’s mines on the backs of heavy trucks, and every day, the roads beneath those trucks pay the price. Surfaces buckle, potholes multiply, and repair crews return again and again to stretches that were resurfaced only months earlier. It is a familiar cycle across India’s coal belt, and one that researchers at NIT Rourkela’s Department of Mining Engineering believe they can finally break, not with a tougher road design, but with the very waste those mines produce.
The team, led by Professor K. Umamaheshwar Rao along with Dr Manoj Kumar Mishra and research scholar Dr Subhasrita Chodhury, has developed and patented a high-strength composite built from coal mine parting, the rock and non-coal material stripped away during extraction, combined with fly ash and a binding agent. The material has now secured Patent No. 597749 under Application No. 202331070306, and pilot-scale field trials are being planned to test how it holds up on real roads over time.
The scale of the problem the innovation is aimed at is considerable. India’s opencast mines, which account for the vast majority of the country’s coal output, generate enormous volumes of overburden and parting material that typically has nowhere useful to go and is simply dumped, straining land and water resources in mining districts. Fly ash from thermal power stations presents a similar story on an even larger canvas: for decades, the country produced far more ash than it could put to use, and it was only after the Ministry of Environment, Forest and Climate Change made fly ash utilisation mandatory near thermal plants, starting with a 1999 notification and reinforced through subsequent amendments, that road builders were required to start incorporating it into embankments under Indian Roads Congress guidelines. Even so, the country was for years producing roughly 90 million tonnes of fly ash a year from thermal plants while using only about 18 million tonnes of it, mostly for road embankments and mine backfilling. That gap has narrowed since, with thermal stations required to bear ash-transport costs within 300 km of road projects and supplying more than 12.9 million tonnes to highway construction in 2019-20 alone, a figure expected to cross 20 million tonnes as more plants come on board.
What makes the NIT Rourkela approach distinct is that it does not rely on fly ash alone, historically used mainly to raise embankments rather than to bear heavy structural loads, but pairs it with coal mine parting material, which carries silica, alumina and clay minerals that lend it compressive strength and stiffness of its own. By testing different ratios of parting material, fly ash and binder, the researchers arrived at a formulation intended specifically for the kind of punishment mining-region roads take on: constant heavy axle loads, repeated truck movement and the wear that follows. Rao has described the technology as directly targeted at coal-mining regions, where existing roads are exposed to exactly this kind of stress and deteriorate faster than roads carrying ordinary traffic.
For NIT Rourkela and for Odisha’s mining economy more broadly, the appeal goes beyond road durability alone. Mishra has framed the composite as a circular-economy solution, converting two waste streams generated at enormous volume, mining overburden and thermal ash, into a single material with genuine engineering and economic value, rather than treating both as disposal problems to be managed separately. If the pilot trials confirm the material’s performance under real traffic and weather conditions, the technology could offer mining regions a way to build infrastructure using the very waste their industries already produce in abundance, cutting both the cost of importing conventional road material and the burden of storing waste that currently serves no purpose.