Swiss major Holcim-managed Ambuja Cements today said it has picked up 60 per cent stake in processed fly ash maker Dirk India for Rs 16.51 crore. "With this acquisition,Dirk India and Dirk Pozzocrete have become subsidiaries of the company," Ambuja Cements said in a communique to the Bombay Stock Exchange (BSE). Dirk Pozzocrete is the subsidiary of the Maharashtra- based firm. The stake was bought from the promoters of Dirk India,Ambuja Cements said,adding that the firm has 2,500 tonnes per day processed fly ash manufacturing capacity. "During the financial year 2010-11,the company (Dirk) generated sales revenue of Rs 55.40 crore and earned EBITDA of Rs 6.8 crore," Ambuja said. In 2001,Dirk India had obtained a 30-year contract for the exclusive recycling of all Pulverised Fuel Ash from Nashik Thermal Power Station of the Maharashtra State Electricity Board.