As of June, Ambuja Cements reported limestone reserves of eight billion tonnes, while UltraTech disclosed reserves of ten billion tonnes. Despite UltraTech's cautious approach to limestone auction bids in the last year, Ambuja Cements has bolstered its reserves by participating in various state auctions, accumulating nearly one billion tonnes.

With the Adani Group as new promoters, Ambuja Cements has aggressively built its limestone reserves, similar to UltraTech’s approach. In FY24, Ambuja Cements secured 587 million tonnes of limestone reserves through auctions and added another 275 million tonnes in the first quarter of FY25. The eight billion tonnes figure does not include the 83 million tonnes won in a recent auction from July to September.

Recent acquisitions have also enhanced Ambuja Cements' limestone holdings. The 2023 acquisition of Sanghi Industries added one billion tonnes to its reserves, and a recent deal to acquire Orient Cement has introduced additional limestone mines in Rajasthan.

Limestone is a crucial raw material in cement production, necessitating that cement units are located near limestone sources. With the top four cement manufacturers planning significant capacity expansions, access to limestone reserves is vital.

Ravleen Sethi, associate director at CareEdge, noted, “Cement companies are pursuing two strategies on limestone: securing supply for planned expansions and preparing for lease expiries and increased costs under the MMDR Act.” Many leases are set to expire from 2030 onwards, which could lead to cost increases and access challenges.

Sethi further explained that lease expirations and new bidding could heighten competition, potentially forcing companies to seek alternative deposits at higher auction premiums and freight costs. In a worst-case scenario, a plant might need to shut down temporarily or permanently if it loses its limestone lease to a new competitor.

In FY24, Ambuja Cements emerged as the top bidder in limestone auctions, with Nuvoco Vistas Corp and JK Cement also actively participating in FY25.