Cemex has started talks to buy India's Mangalam Cement Ltd, reports the Economic Times.  The deal may cost the Mexican company around 2 billion rupees ($1=INR45.45) to INR3 billion, said the paper.  The two companies have been in talks for the last few weeks although Mangalam's managing director KC Jain was unavailable for comment. Cemex has revived its attempt to buy Mangalam for the second time in less than two years. Mangalam has two cement making units in Rajasthan with a combined capacity of 1.2Mta cement.