Bentonite is a soft clay made mostly of the mineral montmorillonite, formed when volcanic ash weathers over millions of years. It can absorb many times its weight in water and swell, which makes it useful in drilling, foundries, pet litter and civil engineering.
In Gujarat, the Indian Bureau of Mines names Kachchh (Kutch) and Bhavnagar districts as the main producing areas. Kutch has deposits spread across the western and central parts of the district, with mines and processing units near the coast and the ports.
Sodium and calcium bentonite
Bentonite comes in two broad types. Sodium bentonite swells strongly and forms a thick gel in water. Calcium bentonite swells much less, but has good bonding and absorbent properties.
Much Indian bentonite is calcium or mixed bentonite. Processors often treat it with soda ash to raise its swelling, which is called activation. Our article on activated bentonite explains how that works and what to ask for.
Resources and production
The Indian Minerals Yearbook 2022, published in March 2024, puts India's bentonite resources at 583 million tonnes, as assessed on 1 April 2015. About 25%, or 144 million tonnes, are in Gujarat, and most of the rest are in Rajasthan.
Bentonite is a minor mineral under Indian mining law, so producers report output to the state, not the national bureau. National production figures are therefore patchy, and you should treat any published total with care.
How it is processed
Raw bentonite is mined from open pits, then dried in the sun or in dryers. Processors may activate it with soda ash, then grind and sieve it to the size the customer needs. Some make granules for cat litter, and some blend it with polymers for drilling or civil grades. Drying matters more than many buyers expect. Clay shipped too wet adds freight weight and can cake, while clay dried too hard can lose some of its swelling.
The processing step, not the mine alone, decides the grade you receive. Two units buying from the same pit can ship very different products. That is why an audit of the processing plant matters, as set out in what a factory audit should contain.
Where it goes
- Drilling fluids for oil, gas and water wells, and for horizontal directional drilling.
- Foundry sand binding, where it holds moulds together.
- Iron ore pelletising, where it binds fine ore into pellets.
- Cat litter, where it clumps and absorbs.
- Civil works, such as piling, diaphragm walls and clay liners.
- Bleaching earth for edible oil refining, after acid activation.
Next step
We find and audit mines and processing plants, check samples, and have lots tested before loading. To match a Kutch bentonite grade to your use, book a free sourcing review.