There are bentonite reserves in Biharand in Jammu and Kashmir, too, but not of good quality. Bentonite is used extensively in drilling fluids and foundries. Rajasthan bentonite is generally used in foundries due to its poor quality.

The 200 mesh size powder of bentonite is sold at a price ranging from Rs 500 to Rs 750 per tonne. There have been no major change in prices in the last few years.Of the total bentonite reserves in the state, only 33 million tonnes have so far been proved with the probable reserves being placed at 107 million tonnes.

In the state the mineral is sodium-based and occurs at a depth of eight metres from surface. The state's share in the value of production in the country is put at 30.02 per cent with Gujarat leading at 69.3 per cent.

Due to mechanised mining, the cost of production is low in Gujarat compared with Rajasthan where the mines are manually operated. The processing involves drying, grinding, sizing and at times use of additive too. The Gujarat bentonite meets the specifications of American Petroleum Institute (API) and Oil Company Material Association (OCMA) in Middle-east.

As against 27 in Gujarat, there is only one pulverising unit in Rajasthan. At one time RSMDC's pulverising plant at Barmer had proposed collaboration with ONGC to augment capacity but the move was given up later due to commercial reasons.

According to RSMDC general manager Ajay KAhluwalia, bentonite mining had a great future if taken on a large scale. The corporation should take on competition from the private operators. "We are certainly looking for some good reserves," he said.

The scope to do mining in the state is very good as reserves had been falling steadily in foreign countries. The mines in Redhill, Baulking, Weburn and Clophill in UK may soon be exhausted. Time has come for RSMDC to broadbase its mining operations if it has to survive in the long run.Its present policy of surviving on what is known as "opportunity cost" may prove to be fatal.